Splicing modulator antibody-drug conjugates and methods of use

Abstract

Linker-drug compounds and antibody-drug conjugates that bind to human oncology targets are disclosed. The linker-drug compounds and antibody-drug conjugates comprise a splicing modulator drug moiety. The disclosure further relates to methods and compositions for use in the treatment of neoplastic disorders by administering the antibody-drug conjugates provided herein. In an embodiment, the splicing modulator comprises a pladienolide or a pladienolide derivative.

Description

SPLICING MODULATOR ANTIBODY-DRUG CONJUGATES AND METHODS OF USE

[01] The present disclosure claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 679,672, filed June 1, 2018; U.S. Provisional Patent Application No. 62 / 679,631, filed June 1, 2018; and U.S. Provisional Patent Application No. 62 / 779,324, filed December 13, 2018. All of the aforementioned applications are incorporated herein by reference in their entirety.

[02] The present disclosure relates to antibody-drug conjugates (ADCs) comprising a splicing modulator and an antibody or antigen binding fragment thereof that binds a human oncology antigen target. The disclosure further relates to methods and compositions useful in the treatment or diagnosis of cancers that express a target antigen and / or are amenable to treatment by disruption of RNA splicing, as well as methods of making those compositions.

[03] The majority of protein-coding genes in the human genome are composed of multiple exons (coding regions) that are separated by introns (non-coding regions). Gene expression results in a single precursor messenger RNA (pre-mRNA). The intron sequences are subsequently removed from the pre-mRNA by a process called splicing, which results in the mature messenger RNA (mRNA). By including different combinations of exons, alternative splicing gives rise to mRNAs encoding distinct protein isoforms.

[04] RNA splicing is catalyzed by the spliceosome, a dynamic multiprotein-RNA complex composed of five small nuclear RNAs (snRNAs U1, U2, U4, U5, and U6) and associated proteins. The spliceosome assembles on pre-mRNAs to establish a dynamic cascade of multiple RNA and protein interactions that catalyze excision of the introns and ligation of exons (Matera and Wang (2014) Nat Rev Mol Cell Biol. 15(2):108-21). Accumulating evidence has linked human diseases to dysregulation in RNA splicing that impact many genes (Scotti and Swanson (2016) Nat Rev Genet. 17(1):19-32).

[05] The spliceosome is an important target in cancer biology. Several studies have now documented significant alterations in the splicing profile of cancer cells, as well as in the splicing factors themselves (Agrawal et al. (2018) Curr Opin Genet Dev. 48:67- 74). Alternative splicing can lead to differential exon inclusion / exclusion, intron retention, or usage of cryptic splice sites (Seiler et al. (2018) Cell Rep. 23(1):282-296). Altogether, these events account for functional changes that may contribute to tumorigenesis or resistance to therapy (Siegfried and Karni (2018) Curr Opin Genet Dev. 48:16-21).

[06] Certain natural products can bind the SF3b spliceosome complex. These small molecules modulate splicing by promoting intron retention and / or exon skipping (Teng et al. (2017) Nat Commun. 8:15522). A significant portion of the resulting transcripts contain premature stop codons triggering nonsense mediated mRNA decay (NMD). Furthermore, because canonical splicing is impaired, canonical transcripts are considerably reduced, which can negatively impact cell function and viability. For this reason, splicing modulators have become a promising class of drugs for the treatment of cancer (Puthenveetil et al. (2016) Bioconjugate Chem. 27:1880-8).

[07] The proto-oncogene human epidermal growth factor receptor 2 (HER2) encodes a transmembrane tyrosine kinase receptor that belongs to the human epidermal growth factor receptor (EGFR) family (King et al. (1985) Science 229:974-6). Overexpression of HER2 enables constitutive activation of growth factor signaling pathways, such as the PI3K-AKT-mTOR pathway, and thereby serves as an oncogenic driver in several types of cancers, including approximately 20% of invasive breast carcinomas (Slamon et al. (1989) Science 244.707-12; Gajria and Chandarlapaty (2011) Expert Rev Anticancer Ther. 11:263-75). Given that HER2 amplification mediates the transformed phenotype, and because HER2 expression is largely restricted to malignant cells, HER2 is a promising antigen for targeting certain cancers and / or delivering novel cancer treatments (Parakh et al. (2017) Cancer Treat Rev. 59:1-21). Additional antigens for targeted delivery of cancer therapies include, but are not limited to, CD138 (also referred to as syndecan-1) and ephrin type-A receptor 2 (EPHA2).

[08] CD138 is a cell surface heparan sulfate proteoglycan that is essential for maintaining cell morphology and interaction with the surrounding microenvironment (Akl et al. (2015) Oncotarget 6(30):28693-715; Szatmari et al. (2015) Dis Markers 2015:796052). In general, the loss of CD138 expression in carcinoma cells reduces cell adhesion to the extracellular matrix and enhances cell motility and invasion (Teng et al. (2012) Matrix Biol. 31:3-16). Increased stromal CD138 expression also alters fibronectin production and extracellular matrix organization (Yang et al. (2011) Am J Pathol. 178:325-35). Additionally, increased expression of CD138 in stromal fibroblasts is associated with angiogenesis and cancer progression (Maeda et al. (2006) Oncogene 25:1408-12). CD138 expression increases during B cell development and its presence is a hallmark of plasma cells (Ribatti (2017) Immunol Lett. 188:64-7). CD138 expression is maintained in multiple myeloma, a malignancy of plasma cells. CD138 is therefore an attractive antigen for the targeted treatment of several cancers and other hematological malignancies (Sherbenou et al. (2015) Blood Rev. 29(2):81-91; Wijdenes et al. (1996) Br J Haematol. 94(2):318-23).

[09] EPHA2 is a transmembrane glycoprotein that is abundantly overexpressed in several malignant cancer-derived cell lines and in advanced forms of cancer (Wykosky and Debinski (2008) Mol Cancer Ref. 6(12):1795-1806). For instance, EPHA2 is strongly overexpressed in approximately 61% of GBM patient tumors (Wykosky et al. (2008) Clin Cancer Res. 14:199-208), 76% of ovarian cancers (Thaker et al. (2004) Clin Cancer Res. 10:5145-50), and 85% of prostate adenocarcinomas (Zeng et al. (2003) Am J Pathol. 163:2271-6). The EPHA2 protein is highly overexpressed with regard to percentage of patient tumors and percentage of cells within a tumor, and is a plasma membrane-localized receptor that can internalize on ligand binding (Walker-Daniels et al. (2002) Mol Cancer Res. 1:79-87). Moreover, expression of EPHA2 is associated with poor prognosis, increased metastasis, and decreased survival. Thus, due to its expression pattern, localization, and functional importance in the outcome of cancer patients, EPHA2 is another attractive antigen for the targeted delivery of novel anti- cancer therapies.

[10] In various embodiments, the present disclosure provides, in part, novel compounds with biological activity against neoplastic cells. The compounds may slow, inhibit, and / or reverse tumor growth in mammals, and may be useful for treating human cancer patients. In various embodiments, the disclosure provides novel antibody-drug conjugates employing the novel compounds or other functional splice inhibitor molecules.

[11] The present disclosure more specifically relates, in various embodiments, to antibody-drug conjugate (ADC) compounds that are capable of binding and killing neoplastic cells. In various embodiments, the ADC compounds disclosed herein comprise a linker that attaches a splicing modulator to a full-length antibody or an antigen binding fragment. In various embodiments, the ADC compounds are also capable of internalizing into a target cell after binding.

[12] In various embodiments, ADC compounds may be represented by Formula (1): Ab-(L-D), (I) wherein Ab is an antibody or an antigen binding fragment thereof which targets a neoplastic cell or another oncology-related target; D is a splicing modulator: L is a linker which covalently attaches Ab to D; and pis an integer from 1 to 15.

[13] In various embodiments, ADC compounds may be represented by Formula (I): Ab-(L-D), (I) wherein Ab is an antibody or an antigen binding fragment thereof which targets a neoplastic cell: (I), or a pharmaceutically acceptable Ris chosen from absent, hydrogen, C+-Ce alkyl groups, C+-Cg alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Cs-Ce heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C1-Cs alkyl) groups; and R¢, RS, and RE are each independently chosen from hydrogen, hydroxyl groups, - O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Ce alkyl groups; R® and R? are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R'7, -0-C(=0)-NR®R8, C4-Cg alkyl groups, and -NR6R18; R'5 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'": R17 is chosen from hydrogen, C1-Ce alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Cgt wherein R', R% R4, R%, R®, R, R8, RS, R'8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C4-Ce alkyl groups, -O-(C+-Cs alkyl) groups, -NR'SR1®, C5-Cg cycloalkyl groups, C1-Ce alkylhydroxy groups, C1-Ce alkylalkoxy groups, benzyl groups, and Ca-Ceg heterocyclyl groups, wherein at least one of R® and R” is hydrogen; and wherein L is a linker which covalently attaches Ab to D; and pis an integer from 1 to 15.

[14] In some embodiments, the antibody or antigen binding fragment is capable of internalization into a target cell. In some embodiments, the linker covalently attaches to L-D has a structure of Formula (II-A): 1I-A), or a pharmaceutically acceptable Ron nk Nu? Rs NE Ren wherein Z’ is chosen from Ri Ry Ry Ron QIN Re NE Ry cand Ri : and wherein all other variables are as defined for Formula (II).

[15] In various other embodiments, ADC compounds may be represented by of Formula (1): wherein Ab is an antibody or an antigen binding fragment thereof which targets a neoplastic cell: D is a splicing modulator of Formula (IV): (IV), or a pharmaceutically R'is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, -O-C(=0)-(C4-Ce alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C1-Cs alkyl) groups; and R¢4, RS, and Re are each independently chosen from hydrogen, hydroxyl groups, - O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Ce alkyl groups; R® and R? are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R'7, -0-C(=0)-NRSR'8, C,-Cg alkyl groups, and -NR'SR18: R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'""; and R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein R', R% R4, R%, R®, R, R8, RS, R'8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C4-Ce alkyl groups, -O-(C+-Cs alkyl) groups, -NR'SR1®, C5-Cq cycloalkyl groups, C1-Ce alkylhydroxy groups, C1-Ce alkylalkoxy groups, benzyl groups, and Ca-Cg heterocyclyl groups, wherein at least one of R® and R” is hydrogen; and wherein L is a linker which covalently attaches Ab to D; and pis an integer from 1 to 15.

[16] In some embodiments, the antibody or antigen binding fragment is capable of internalization into a target cell. In some embodiments, the linker covalently attaches to the splicing modulator (“L-D”), and L-D has a structure of Formula (IV-A): (IV-A), or a pharmaceutically [171 In various other embodiments, ADC compounds may be represented by Formula 0: Ab-(L-D), (I) wherein Ab is an antibody or an antigen binding fragment thereof which targets a neoplastic cell: (VI), or a pharmaceutically acceptable salt thereof, wherein: R' and R® are each independently chosen from hydrogen, C1-Ce alkyl groups, C1-Ce alkylalkoxy groups, C-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Ce alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Cs-Ce heterocyclyl groups, -O-C(=0)-(C1-Cs alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Ce alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C1-Cs alkyl) groups; R¢4, RS, and Re are each independently chosen from hydrogen, hydroxyl groups, - O-(C4-Ce alkyl) groups, -O-C(=0)-(C4-Cs alkyl) groups, and C-Ce alkyl groups; R® and R? are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R'7, -0-C(=0)-NRSR'8, C4-Cg alkyl groups, -NR'*R'®, and a linker; R10 is chosen from hydrogen, C1-Ce alkyl groups, -C(=0)-(C1-Cs alkyl) groups, and -CDa; R'® and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-0O-R'"; R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; and ais1,2,3,4,56,7,8, 9, or10; wherein R', R?, R4, R®, R®, R7, R¢, R?, R'0, R35, R', and R'7 are each independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C1-Cs alkyl groups, -O-(C1-Ce alkyl) groups, -NR'*R'8, Cs-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Cs-Ce heterocyclyl groups; wherein at least one of R® and R? is hydrogen; and wherein R' and R® cannot both be absent: and wherein L is a linker which covalently attaches Ab to D; and pis an integer from 1 to 15.

[18] In some embodiments, the antibody or antigen binding fragment is capable of internalization into a target cell. In some embodiments, the linker covalently attaches to the splicing modulator (“L-D”), and L-D has a structure of Formula (VI-A): 0 Ronin Ra Rg Neg Rio x Re oT o 1 1 3 R, R hi - PS PRS PN SANA 0 OH Rg “Rs ) (VI-A), or a pharmaceutically acceptable salt thereof.

[19] In various other embodiments, ADC compounds may be represented by Formula on: wherein Ab is an antibody or an antigen binding fragment thereof which targets a neoplastic cell: D is a splicing modulator of Formula (VIII): (VIII), or a pharmaceutically acceptable salt thereof, R'is chosen from absent, hydrogen, C+-Ce alkyl groups, C+-Ce alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Cs-Cs heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDa; R? is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R* is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, -O-C(=0)- (C1-Cs alkyl) groups, and C4-Cs alkyl groups: and R10 is chosen from 3 to 10 membered carbocycles and 3 to 10 membered heterocycles, each of which is substituted with 0 to 3 R#, wherein each R? is independently chosen from halogens, C+-Cs alkyl groups, -O-(C-Ce)alkyl groups, C+-Cs alkylalkoxy groups, C4-Ce alkylhydroxy groups, -S(=0)w-(4 to 7 membered heterocycles), 4 to 7 membered carbocycles, and 4 to 7 membered heterocycles; RS and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-O-R'": and R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein R', R%, R4, R', R$, R'8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C+-Ce alkyl groups, -O-(C+-Cs alkyl) groups, -NR'$R'®, Ca-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Cs alkylalkoxy groups, benzyl groups, and Ci-Cg heterocyclyl groups; and wherein each R# is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, -NR13R18, C+-Cs alkyl groups, -(C=0)-(C1-Cs alkyl) groups, -(C=0)-(C1-Ce alkyl)-(Ca-C10 heterocyclyl groups), -S(=O)w-(Ca-Cs heterocyclyl) groups, and C4-Cs alkylcarboxylic acid groups, each of which is substituted with 0, 1, or 2 groups independently chosen from halogens, hydroxyl groups, -NR"*R"6, and C+-Cs alkyl groups; and and wherein L is a linker which covalently attaches Ab to D; and pis an integer from 1 to 15.

[20] In some embodiments, the antibody or antigen binding fragment is capable of internalization into a target cell. In some embodiments, the linker covalently attaches to and L-D has a structure of Formula (VIII-A): ‘lI-A), or a pharmaceutically acceptable salt thereof. the splicing modulator comprises a modulator of the SF3b complex. In some embodiments, the splicing modulator comprises a pladienolide or a pladienolide derivative. In some embodiments, the splicing modulator comprises pladienclide D or a pladienolide D derivative. In some embodiments, the pladienolide D or derivative comprises D2, D1, D4, D8, D10, D11 (E7107), D20, D21, D22, D12, or D25. In some embodiments, the pladienolide D or derivative comprises D2. In some embodiments, the pladienolide D or derivative comprises D1. In some embodiments, the pladienolide D or derivative comprises D4. In some embodiments, the pladienolide D or derivative comprises D12.

[22] In some embodiments, the pladienolide D or derivative is a zwitterionic pladienolide D or derivative. In some embodiments, the zwitterionic pladienolide D or derivative comprises D22 or D25.

[23] In some other embodiments, the splicing modulator comprises pladienolide B or a pladienolide B derivative. In some embodiments, the pladienolide B or derivative comprises D9, D18, D19, or D13. In some embodiments, the splicing modulator comprises an aryl pladienclide. In some embodiments, the aryl pladienolide comprises D15, D14, D16, D17, D286, or D33. In some embodiments, the aryl pladienolide comprises D15. In some embodiments, the aryl pladienolide is a zwitterionic aryl pladienolide. In some embodiments, the zwitterionic aryl pladienolide comprises D33.

[24] In some embodiments, the splicing modulator comprises D1:

[56] In some embodime es D32; (D32). [571 In some emboc 33:

[58] In some emboc 34: (D34).

[59] In some embodime smprises D35: (D35).

[60] In some embodime smprises one of the drug moieties listed in Table 7. In some embodiments, the splicing modulator comprises D1, D2, D3, D4, D4’, D5, D8, D7, D8, D9, D10, D11, D12, D183, D14, D15, D186, D17, D18, D19, D20, D21, D22, D23, D24, D25, D26, D27, D28, D29, D30, D31, D32, D33, D34, and / or D35.

[61] In some embodiments, a splicing modulator is disclosed, as well as its use as a therapeutic alone or as part of an ADC. In some embodiments, the splicing modulator comprises D4, D4’, D12, D15, D8, D9, D10, D13, D18, D19, D20, D21, D22, D25, or D33.

[62] In some embodiments, the splicing modulator comprises D4 and the linker comprises MC-Val-Cit-pABC. In some embodiments, the splicing modulator comprises D4 and the linker comprises MC-B-glucuronide. In some embodiments, the splicing modulator comprises D12 and the linker comprises MC-Val-Cit-pABC. In some embodiments, the splicing modulator comprises D12 and the linker comprises MC-B- glucuronide. In some embodiments, the splicing modulator comprises D15 and the linker comprises MC-Val-Ala-pAB.

[63] In various embodiments, the linker used in an ADC disclosed herein is stable outside a cell, such that the ADC remains intact when present in extracellular conditions, but is capable of being cleaved upon internalization into a cell, e.g., a tumor or cancer cell. In some embodiments, the splicing modulator is cleaved from the antibody or antigen binding fragment when the ADC enters a cell that expresses an antigen targeted by the antibody or antigen binding fragment of the ADC. In some embodiments, the linker is a cleavable linker.

[64] In some embodiments, the linker comprises a cleavable peptide moiety. In some embodiments, the cleavable peptide moiety is cleavable by an enzyme. In some embodiments, the cleavable peptide moiety or linker comprises an amino acid unit. In some embodiments, the amino acid unit comprises valine-citrulline (“Val-Cit” or “VC”). In some other embodiments, the amino acid unit comprises valine-alanine (“Val-Ala” or “VA”). In some other embodiments, the amino acid unit comprises glutamic acid-valine- citrulline (“Glu-Val-Cit’ or “EVC”). In some other embodiments, the amino acid unit comprises alanine-alanine-asparagine (“Ala-Ala-Asn” or “AAN").

[65] In some embodiments, the linker comprises a cleavable glucuronide moiety. In some embodiments, the cleavable glucuronide moiety is cleavable by an enzyme. In some embodiments, the cleavable glucuronide moiety is cleavable by a glucuronidase. In some embodiments, the cleavable glucuronide moiety is cleavable by B- glucuronidase.

[66] In some embodiments, the linker comprises at least one spacer unit. In some embodiments, the spacer unit or linker comprises a polyethylene glycol (PEG) moiety. In some embodiments, the PEG moiety comprises -(PEG).~ and mis an integer from 1 to 10. In some embodiments, mis 2. In some other embodiments, the spacer unit or linker comprises an alkyl moiety. In some embodiments, the alkyl moiety comprises - (CH2)r and n is an integer from 1 to 10. In some embodiments, nis 2. In some embodiments, nis 5. In some embodiments, nis 6. [671 In some embodiments, the spacer unit attaches to the antibody or antigen binding fragment via a maleimide (Mal) moiety (“Mal-spacer unit’). In some embodiments, the Mal-spacer unit is reactive with a cysteine residue on the antibody or antigen binding fragment. In some embodiments, the Mal-spacer unit is joined to the antibody or antigen binding fragment via a cysteine residue on the antibody or antigen binding fragment.

[68] In some embodiments, the linker comprises the Mal-spacer unit and a cleavable peptide moiety. In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the cleavable peptide moiety or amino acid unit comprises Val-Cit. In some embodiments, the cleavable peptide moiety or amino acid unit comprises Val-Ala. In some embodiments, the cleavable peptide moiety or amino acid unit comprises Glu-Val-Cit. In some embodiments, the cleavable peptide moiety or amino acid unit comprises Ala-Ala-Asn. In some embodiments, the Mal-spacer unit comprises an alkyl moiety. In some embodiments, the Mal-spacer unit comprises a PEG moiety. In some embodiments, the Mal-spacer unit comprises a maleimidocaproy! (MC). In some embodiments, the Mal-spacer unit attaches the antibody or antigen binding fragment to the cleavable moiety in the linker. In some embodiments, the cleavable moiety in the linker comprises a cleavable peptide moiety. In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the cleavable peptide moiety or amino acid unit comprises Val-Cit, Val-Ala, Glu-Val-Cit, or Ala-Ala-Asn. In some embodiments, the linker comprises MC-Val-Cit. In some embodiments, the linker comprises MC-Val-Ala. In some embodiments, the linker comprises MC-Glu-Val-Cit. In some embodiments, the linker comprises MC-Ala-Ala- Asn. In some embodiments, the Mal-spacer unit comprises an alkyl moiety. In some embodiments, the Mal-spacer unit comprises a PEG moiety. In some embodiments, the Mal-spacer unit comprises a maleimidocaproyl (MC).

[69] In some embodiments, the cleavable moiety in the linker is directly joined to the splicing modulator, or a spacer unit attaches the cleavable moiety in the linker to the splicing modulator. In some embodiments, cleavage of the conjugate releases the splicing modulator from the antibody or antigen binding fragment and linker. In some embodiments, the spacer unit attaching the cleavable moiety in the linker to the splicing modulator is self-immolative.

[70] In some embodiments, the spacer unit attaching the cleavable moiety in the linker to the splicing modulator comprises a p-aminobenzyloxycarbonyl (PABC). In some embodiments, the pABC attaches the cleavable moiety in the linker to the splicing modulator. In some embodiments, the cleavable moiety in the linker comprises a cleavable peptide moiety. In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the cleavable peptide moiety or amino acid unit comprises Val-Cit, Val-Ala, Glu-Val-Cit, or Ala-Ala-Asn. In some embodiments, the linker comprises Val-Cit-pABC. In some other embodiments, the linker comprises Val-Ala-pABC. In some embodiments, the linker comprises Glu-Val- Cit-pABC. In some embodiments, the linker comprises Ala-Ala-Asn-pABC.

[71] In some embodiments, the spacer unit attaching the cleavable moiety in the linker to the splicing modulator comprises a p-aminobenzyl (pAB). In some embodiments, the pAB attaches the cleavable moiety in the linker to the splicing modulator. In some embodiments, the cleavable moiety in the linker comprises a cleavable peptide moiety. In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the cleavable peptide moiety or amino acid unit comprises Val-Cit, Val-Ala, Glu-Val-Cit, or Ala-Ala-Asn. In some embodiments, the linker comprises Val-Cit-pAB. In some other embodiments, the linker comprises Val-Ala-pAB. In some other embodiments, the linker comprises Glu-Val-Cit- PAB. In some other embodiments, the linker comprises Ala-Ala-Asn-pAB.

[72] In various embodiments, the linker is a non-cleavable linker. In some embodiments, the splicing modulator of the ADC is released by degradation of the antibody or antigen binding fragment. In some embodiments, the linker remains covalently associated with at least one amino acid of the antibody and drug upon internalization by and degradation within the target cell.

[73] In some embodiments, the linker is a non-cleavable linker comprising at least one spacer unit. In some embodiments, the spacer unit or linker comprises a polyethylene glycol (PEG) moiety. In some embodiments, the PEG moiety comprises - (PEG) and mis an integer from 1 to 10. In some embodiments, mis 2. In some other embodiments, the spacer unit or linker comprises an alkyl moiety. In some embodiments, the alkyl moiety comprises -(CHz),- or -(CHz2)-O-(CHz)» and nis an integer from 1 to 10. In some embodiments, nis 2. In some embodiments, nis 5. In some embodiments, nis 6.

[74] In some embodiments, the spacer unit in a non-cleavable linker attaches to the antibody or antigen binding fragment via a maleimide (Mal) moiety (“Mal-spacer unit”). In some embodiments, the Mal-spacer unit is reactive with a cysteine residue on the antibody or antigen binding fragment. In some embodiments, the Mal-spacer unit is joined to the antibody or antigen binding fragment via a cysteine residue on the antibody or antigen binding fragment. In some embodiments, the Mal-spacer unit comprises an alkyl moiety. In some embodiments, the Mal-spacer unit comprises a PEG moiety. In some embodiments, the linker or Mal-spacer unit comprises a maleimidocaproyl (MC). In some embodiments, the linker or Mal-spacer unit comprises a maleimidocaproyl (MC) and at least one additional spacer unit. In some embodiments, the linker or Mal-spacer unit comprises MC-(PEG)2. In some embodiments, the linker or Mal-spacer unit comprises MC-(PEG). and at least one additional spacer unit. In some embodiments, the linker or Mal-spacer unit comprises Mal-Hex. In some embodiments, the linker or Mal-spacer unit comprises Mal-Hex and at least one additional spacer unit. In some embodiments, the linker or Mal-spacer unit comprises Mal-Et. In some embodiments, the linker or Mal-spacer unit comprises Mal-Et and at least one additional spacer unit. In some embodiments, the linker or Mal-spacer unit comprises Mal-Et-O-Et. In some embodiments, the linker or Mal-spacer unit comprises Mal-Et-O-Et and at least one additional spacer unit. In some embodiments, the Mal-spacer unit attaches the antibody or antigen binding fragment to the splicing modulator.

[75] In various embodiments, ADC compounds may be represented by Formula (1): Ab-(L-D), (I) wherein Ab is an antibody or an antigen binding fragment thereof which targets a neoplastic cell or another oncology-related target such as a cancer antigen (e.g., any of the antibody or binding domain sequences disclosed herein); D is any small molecule suitable for treating a cancer (e.g., a splicing modulator, e.g., any of the splicing modulators disclosed herein); L is a linker which covalently attaches Ab to D (e.g., any of the linkers disclosed herein); and p is an integer from 1 to 15.

[76] In some embodiments, Ab is selected from any of the antibody or binding domain sequences disclosed herein. In some embodiments, Ab is an antibody or binding domain sequence which targets HER2 and / or a HER2-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets CD 138 and / or a CD138-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets EPHA2 and / or an EPHA2- expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets MSLN and / or a MSLN-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets FOLH1 and / or a FOLH1-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets CDH6 and / or a CDH6-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets CEACAMS and / or a CEACAMS-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets CFC1B and / or a CFC1B-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets ENPP3 and / or an ENPP3-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets FOLR1 and / or a FOLR1-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets HAVCR1 and / or a HAVCR1-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets KIT and / or a KIT-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets MET and / or a MET-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets MUC 16 and / or a MUC16- expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets SLC39A6 and / or a SLC39A6-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets SLC44A4 and / or a SLC44A4-expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets STEAP1 and / or a STEAP1- expressing neoplastic cell. In some embodiments, Ab is an antibody or binding domain sequence which targets another cancer antigen. [771 In some embodiments, D is a splicing modulator. In some embodiments, D is selected from any of the splicing modulators disclosed herein. In some embodiments, D is a splicing modulator selected from D2, D1, D4, D8, D10, D11 (E7107), D20, D21, D22, D12, D25, D9, D18, D19, D13, D15, D14, D16, D17, D26, and D33, or any derivative thereof. In some embodiments, D is a splicing modulator selected from D4, D12, D15, D8, D9, D10, D13, D18, D18, D20, D21, D22, D25, and D33, or any derivative thereof. In some embodiments, D is a splicing modulator comprising D2 or any derivative thereof. In some embodiments, D is a splicing modulator comprising D1 or any derivative thereof.

[78] In some embodiments, L is selected from any of the linkers disclosed herein, or any combination of linker components disclosed herein. In some embodiments, L is a linker comprising MC-Val-Cit-pABC, Mal-(PEG)>-CO, MC-Val-Ala-pAB, MC-Val-Ala- PABC, MC-Val-Cit-pAB, Mal-Hex, Mal-Et, or Mal-Et-O-Et. In some embodiments, the linker may also comprise one or more additional spacer units. In some embodiments, L is an ADL1, ADL2, ADLS5, ADLS, ADL7, ADL10, ADL12, ADL13, ADL14, ADL15, ADL21, ADL22, or ADL23 linker. In some embodiments, L is an ADL1, ADL2, ADL5, ADLS6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker. In some embodiments, L is an ADL12, ADL14, or ADL15 linker. In some embodiments, the ADL1, ADL2, ADL5, ADL6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker may also comprise one or more additional spacer units. In some embodiments, L is an ADL1 linker and may optionally comprise one or more additional spacer units. In some embodiments, L is an ADL2 linker and may optionally comprise one or more additional spacer units. In some embodiments, L is an ADLS linker and may optionally comprise one or more additional spacer units. In some embodiments, L is an ADL6 linker and may optionally comprise one or more additional spacer units. In some embodiments, L is an ADL? linker and may optionally comprise one or more additional spacer units. In some embodiments, L is an ADL12 linker and may optionally comprise one or more additional spacer units. In some embodiments, L is an ADL14 linker and may optionally comprise one or more additional spacer units. In some embodiments, L is an ADL15 linker and may optionally comprise one or more additional spacer units. In various embodiments of the ADCs described herein, p is from 1 to 10. In various embodiments, p is from 2 to 8. In various embodiments, p is from 4 to 8. In some embodiments, pis 4. In some embodiments, pis 8.

[79] In some embodiments, L-D of Formula (I) is ADL1-D1. In some embodiments, L- D of Formula (I) is ADL6-D1. In some embodiments, L-D of Formula (I) is ADL5-D2. In some embodiments, L-D of Formula (I) is ADL1-D18. In some embodiments, L-D of Formula (I) is ADL5-D19. In some embodiments, L-D of Formula (I) is ADL14-D1. In some embodiments, L-D of Formula (I) is ADL12-D1. In some embodiments, L-D of Formula (I) is ADL15-D1. In some embodiments, L-D of Formula (I) is ADL12-D20. In some embodiments, L-D of Formula (I) is ADL10-D1. In some embodiments, L-D of Formula (I) is ADL12-D2. In some embodiments, L-D of Formula (I) is ADL15-D2. In some embodiments, L-D of Formula (I) is ADL12-D21. In some embodiments, L-D of Formula (I) is ADL6-D9. In some embodiments, L-D of Formula (I) is ADL1-D4. In some embodiments, L-D of Formula (I) is ADL1-D3. In some embodiments, L-D of Formula (1) is ADL1-D12. In some embodiments, L-D of Formula (I) is ADL1-D7. In some embodiments, L-D of Formula (I) is ADL1-D6. In some embodiments, L-D of Formula (I) is ADL1-D5. In some embodiments, L-D of Formula (I) is ADL22-D4. In some embodiments, L-D of Formula (I) is ADL5-D10. In some embodiments, L-D of Formula (I) is ADL5-D11. In some embodiments, L-D of Formula (1) is ADL1-D13. In some embodiments, L-D of Formula (I) is ADL1-D8. In some embodiments, L-D of Formula (I) is ADL1-D22. In some embodiments, L-D of Formula (1) is ADL5-D25. In some embodiments, L-D of Formula (I) is ADL12-D22. In some embodiments, L-D of Formula (1) is ADL5-D15. In some embodiments, L-D of Formula (1) is ADL1-D14. In some embodiments, L-D of Formula (I) is ADL5-D26. In some embodiments, L-D of Formula (I) is ADL1-D16. In some embodiments, L-D of Formula (1) is ADL5-D17. In some embodiments, L-D of Formula (I) is ADL1-D33. In some embodiments, L-D of Formula (I) is ADL1-D28. In some embodiments, L-D of Formula (I) is ADL1-D31. In some embodiments, L-D of Formula (I) is ADL1-D29. In some embodiments, L-D of Formula (I) is ADL1-D35. In some embodiments, L-D of Formula (1) is ADL5-D32. In some embodiments, L-D of Formula (I) is ADL5-D27. In some embodiments, L-D of Formula (1) is ADL12-D35. In some embodiments, L-D of Formula (I) is ADL12-D28. In some embodiments, L-D of Formula (I) is ADL1-D23. In some embodiments, L-D of Formula (1) is ADL1-D24.

[80] In some embodiments, a pool of ADCs is provided whereby random conjugation occurs, and the average p in the pool is between about 2 and about 8. In some embodiments, a pool of ADCs is provided whereby random conjugation occurs, and the average p in the pool is between about 4 and about 8. In some embodiments, a pool of ADCs is provided whereby random conjugation occurs, and the average p in the pool is about 4. In some embodiments, a pool of ADCs is provided whereby random conjugation occurs, and the average p in the pool is about 8. Compositions (e.g., pharmaceutical compositions) comprising multiple copies of any of the described ADCs, wherein the average drug loading (average p) of the ADCs in the composition is from about 3.5 to about 5.5 (e.g., about 4), or from about 7 to about 9 (e.g., about 8) are provided herein.

[81] In some embodiments, the antibody or antigen binding fragment (Ab) of the ADC targets a neoplastic cell derived from a hematological malignancy or a solid tumor. In some embodiments, the antibody or antigen binding fragment targets a neoplastic cell derived from a hematological malignancy. In some embodiments, the hematological malignancy is selected from a B-cell malignancy, a leukemia (e.g., acute myeloid leukemia), a lymphoma, and a myeloma (e.g., multiple myeloma). In some embodiments, the hematological malignancy is selected from acute myeloid leukemia and multiple myeloma. In some embodiments, the antibody or antigen binding fragment targets a neoplastic cell derived from a solid tumor. In some embodiments, the solid tumor is selected from breast cancer (e.g., HER2-positive breast cancer), gastric cancer (e.g., gastric adenocarcinoma), prostate cancer, ovarian cancer, lung cancer (e.g., lung adenocarcinoma), uterine cancer (e.g., uterine serous endometrial carcinoma), salivary duct carcinoma, melanoma, colon cancer, cervical cancer, pancreatic cancer, kidney cancer, colorectal cancer, and esophageal cancer. In some embodiments, the solid tumor is selected from HER2-positive breast cancer, gastric adenocarcinoma, prostate cancer, and osteosarcoma.

[82] In various embodiments, the antibody or antigen binding fragment (Ab) of the ADC is an anti-HER2 antibody or an antigen binding fragment thereof. In some embodiments, the antibody or antigen binding fragment binds to HER2 and targets HER2-expressing neoplastic cells (i.e., the ADC targets HER2-expressing neoplastic cells). In some embodiments, the antibody or antigen binding fragment of the ADC is an internalizing anti-HER2 antibody or internalizing antigen binding fragment thereof.

[83] In some embodiments, the anti-HER2 antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDRS3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDRS3). In some embodiments, the anti-HER2 antibody or antigen binding fragment is an internalizing antibody or internalizing antigen binding fragment. In some embodiments, the anti-HER2 antibody or antigen binding fragment comprises human framework sequences. In some embodiments, the anti-HER2 antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:20. In some embodiments, the anti-HER2 antibody or antigen binding fragment comprises a human IgG heavy chain constant region. In some embodiments, the anti- HER2 antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region. In some embodiments, the anti-HER2 antibody or antigen binding fragment comprises a human Ig kappa or lambda light chain constant region. In some embodiments, the anti-HER2 antibody or antigen binding competes for binding and / or binds the same epitope as an antibody comprising a heavy chain variable domain of SEQ ID NO:19 and a light chain variable domain of SEQ ID NO:20.

[84] In various embodiments, the antibody or antigen binding fragment (Ab) of the ADC is an anti-CD138 antibody or an antigen binding fragment thereof. In some embodiments, the antibody or antigen binding fragment binds to CD138 and targets CD138-expressing neoplastic cells (i.e., the ADC targets CD138-expressing neoplastic cells). In some embodiments, the antibody or antigen binding fragment of the ADC is an internalizing anti-CD138 antibody or internalizing antigen binding fragment thereof.

[85] In some embodiments, the anti-CD138 antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR2), and SEQ ID NO:9 (HCDRS3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDRS3). In some embodiments, the anti-CD138 antibody or antigen binding fragment is an internalizing antibody or internalizing antigen binding fragment. In some embodiments, the anti-CD138 antibody or antigen binding fragment comprises human framework sequences. In some embodiments, the anti-CD138 antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:22. In some embodiments, the anti-CD138 antibody or antigen binding fragment comprises a murine IgG2a heavy chain constant region. In some embodiments, the anti-CD138 antibody or antigen binding fragment comprises a murine Ig kappa light chain constant region. In some embodiments, the anti-CD138 antibody or antigen binding fragment comprises a human IgG heavy chain constant region. In some embodiments, the anti-CD138 antibody or antigen binding fragment comprises a human 1gG2a heavy chain constant region. In some embodiments, the anti-CD138 antibody or antigen binding fragment comprises a human Ig kappa or lambda light chain constant region. In some embodiments, the anti-CD138 antibody or antigen binding competes for binding and / or binds the same epitope as an antibody comprising a heavy chain variable domain of SEQ ID NO:21 and a light chain variable domain of SEQ ID NO:22.

[86] In various embodiments, the antibody or antigen binding fragment (Ab) of the ADC is an anti-EPHA2 antibody or an antigen binding fragment thereof. In some embodiments, the antibody or antigen binding fragment binds to EPHA2 and targets EPHA2-expressing neoplastic cells (i.e., the ADC targets EPHA2-expressing neoplastic cells). In some embodiments, the antibody or antigen binding fragment of the ADC is an internalizing anti-EPHA2 antibody or internalizing antigen binding fragment thereof. [871 In some embodiments, the anti-EPHA2 antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR?2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDR3). In some embodiments, the anti-EPHA2 antibody or antigen binding fragment is an internalizing antibody or internalizing antigen binding fragment. In some embodiments, the anti-EPHA2 antibody or antigen binding fragment comprises human framework sequences. In some embodiments, the anti-EPHA2 antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:24. In some embodiments, the anti-EPHA2 antibody or antigen binding fragment comprises a human IgG heavy chain constant region. In some embodiments, the anti-EPHA2 antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region. In some embodiments, the anti-EPHA2 antibody or antigen binding fragment comprises a human Ig kappa or lambda light chain constant region. In some embodiments, the anti-EPHA2 antibody or antigen binding competes for binding and / or binds the same epitope as an antibody comprising a heavy chain variable domain of SEQ ID NO:23 and a light chain variable domain of SEQ ID NO:24.

[88] Also provided herein, in various embodiments, are compounds comprising a linker-drug defined by the generic formula: L-D, wherein L = a linker moiety, and D = a drug moiety (e.g., a splicing modulator drug moiety). In various embodiments, the linker-drug (L-D) compounds disclosed herein may attach to an antibody or antigen binding fragment and / or are suitable for use in the ADCs disclosed herein, e.g., in ADCs of Formula (I).

[89] In various embodiments, the linker-drug (L-D) compounds disclosed herein comprise a linker-drug structure according to Formula (Ill). In various embodiments, the compound of Formula (11): (Ill), or a pharmaceutically acceptable R'is chosen from absent, hydrogen, C+-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Cs-Ce heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDs; R2 is absent or a linker; R? is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; and R*, R, and R® are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R"7, -0-C(=0)-NRSR18, C4-Cg alkyl groups, -NR'R'¢, and a linker; R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'"; R17 is chosen from hydrogen, C1-Cs alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; and Rony 5 % Ren on% SN ~ ¥ ~~ Ro~N Rs ll) Re~N N ! | Rene J from Ry Ry Ry Ry 32, R®, R4 RS, RS, R7, R&R, R8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR$R8, C5-Cs cycloalkyl groups, C+-Cs alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein at least one of R® and R? is hydrogen; and wherein if R2 is a linker, then neither R® or R” is a linker, and if R® or R7 is a linker, then R2 is absent.

[90] In various other embodiments, the linker-drug (L-D) compounds disclosed herein comprise a linker-drug structure according to Formula (V). In various embodiments, the present disclosure provides a linker-drug (L-D) compound of Formula (V): (V), or a pharmaceutically R'is chosen from absent, hydrogen, C+-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Cs-Ce heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDs; R2 is absent or a linker; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C+-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; and R¢4, RS, and RE are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R” are each independently chosen from hydrogen, -O-R"", -O-C(=0)-R", -0-C(=0)-NRSR18, C4-Cg alkyl groups, -NR'R'¢, and a linker; R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-0O-R'": and R'7 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Csg heterocyclyl groups: wherein R, R2, R?, R4, R%, R®, R7, R®, R'5, R'®, and R'? are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR*R8, C4-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Ca-Cs heterocyclyl groups; wherein at least one of R® and R7 is hydrogen; and wherein if R? is a linker, then neither R® or R7 is a linker, and if R® or R7 is a linker, then R2 is absent.

[91] In various other embodiments, the linker-drug (L-D) compounds disclosed herein comprise a linker-drug structure according to Formula (VII). In various embodiments, the present disclosure provides a linker-drug (L-D) compound of Formula (VII): (VII), or a pharmaceutically acceptable R' and R® are each independently chosen from absent, hydrogen, C4-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, -O-C(=0)-(C+-Cs alkyl) groups, and -CDa; R2? is absent or a linker; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Ce alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C1-Cs alkyl) groups; R¢, RS, and RE are each independently chosen from hydrogen, hydroxyl groups, - O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Ce alkyl groups; R® and R? are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R'7, -0-C(=0)-NRSR'8, C,-Cs alkyl groups, -NR'R'¢, and a linker; Ris chosen from hydrogen, C1-Cs alkyl groups, -C(=0)-(C1-Cs alkyl) groups, and -CDs; R'5 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'": R17 is chosen from hydrogen, C1-Ce alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and C;-Csg heterocyclyl groups: and ais1,2,3,4,56,7,8, 9, or10; wherein R", R?, R3, R% RS, R®, R7, R8, R®, R™®, R™, R®, and R'” are each independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C1-Cs alkyl groups, -O-(C1-Ce alkyl) groups, -NR'5R'8, Cs-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, Ci-Ce alkylalkoxy groups, benzyl groups, and Cs-Ce heterocyclyl groups; wherein at least one of R® and R is hydrogen; wherein if R? is a linker, then neither R® or R7 is a linker, and if R® or R7 is a linker, then R? is absent; and wherein R! and R® cannot both be absent.

[92] In various other embodiments, the linker-drug (L-D) compounds disclosed herein comprise a linker-drug structure according to Formula (IX). In various embodiments, the a linker-drug (L-D) compound of Formula (IX): (IX), or a pharmaceutically acceptable salt thereof, wherein: sent, hydrogen, C+-Ce alkyl groups, C+-Ce alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Cs-Ce heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDs; R2?is a linker; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C+-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R* is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, -O-C(=0)- (C+-Cs alkyl) groups, and C4-Cg alkyl groups; R10 is chosen from 3 to 10 membered carbocycles and 3 to 10 membered heterocycles, each of which is substituted with 0 to 3 R#, wherein each R? is independently chosen from halogens, C+-Cs alkyl groups, -O-(C1-Ce)alkyl groups, C-Cs alkylalkoxy groups, Ci-Ce alkylhydroxy groups, -S(=O)w~(4 to 7 membered heterocycles), 4 to 7 membered carbocycles, and 4 to 7 membered heterocycles; RS and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-O-R'": and R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein R', R2, R%, R4, RR", R"8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C+-Ce alkyl groups, -O-(C+-Cs alkyl) groups, -NR'5R"8, C3-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Cs alkylalkoxy groups, benzyl groups, and Ci-Cg heterocyclyl groups; and wherein each Re is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, -NR'5R'8, C4-Ce alkyl groups, -(C=0)-(C1-Ce alkyl) groups, -(C=0)-(C1-Cs alkyl)-(Cs-C1o heterocyclyl)groups, and C+-Cs alkylcarboxylic acid groups, each of which is substituted with 0, 1, or 2 groups independently chosen from halogens, hydroxyl groups, -NR'$R8, and C+-Cs alkyl groups; and wis 0, 1, or2.

[93] Also, in various embodiments, provided herein are therapeutic uses for the described ADC compounds and compositions, e.g., in treating a neoplastic disorder, e.g., a cancer. In certain aspects, the present disclosure provides methods of treating a neoplastic disorder, e.g., a cancer that expresses an antigen targeted by the antibody or antigen binding fragment of the ADC, such as HER2, CD138, EPHA2, MSLN, FOLH1, CDH8, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A8, SLC44A4, or STEAP1.

[94] In certain aspects, the present disclosure provides methods of treating a subject having or suspected of having a neoplastic disorder by administering to the subject a therapeutically effective amount and / or regimen of any one of the described ADCs or compositions. In some embodiments, the neoplastic disorder is a hematological malignancy or a solid tumor. In some embodiments, the neoplastic disorder is a hematological malignancy. In some embodiments, the hematological malignancy is selected from a B-cell malignancy, a leukemia, a lymphoma, and a myeloma. In some embodiments, the hematological malignancy is selected from acute myeloid leukemia and multiple myeloma. In some embodiments, the neoplastic disorder is a solid tumor. In some embodiments, the solid tumor is selected from breast cancer (e.g., HER2- positive breast cancer), gastric cancer (e.g., gastric adenocarcinoma), prostate cancer, ovarian cancer, lung cancer (e.g., lung adenocarcinoma), uterine cancer (e.g., uterine serous endometrial carcinoma), salivary duct carcinoma, melanoma, colon cancer, cervical cancer, pancreatic cancer, kidney cancer, colorectal cancer, and esophageal cancer. In some embodiments, the solid tumor is selected from HER2-positive breast cancer, gastric adenocarcinoma, prostate cancer, and osteosarcoma.

[95] In some embodiments, treatment with the antibody-drug conjugate or composition induces bystander killing of neoplastic cells which do not express a target antigen but are adjacent to neoplastic cells which express a target antigen. In some embodiments, the subject has one or more neoplastic cells which express a target antigen.

[96] In some embodiments, the target antigen is HER2. In some embodiments, the one or more neoplastic cells are derived from a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer (e.g., lung adenocarcinoma), uterine cancer (e.g., uterine serous endometrial carcinoma), osteosarcoma, or salivary duct carcinoma. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-HER?2 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non- responsive, or poorly responsive to treatment with a splicing modulator when administered alone. [971 In some embodiments, the target antigen is CD138. In some embodiments, the one or more neoplastic cells are derived from a CD138-expressing multiple myeloma. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-CD138 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[98] In some embodiments, the target antigen is EPHA2. In some embodiments, the one or more neoplastic cells are derived from an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-EPHA2 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[99] In some embodiments, the target antigen is MSLN. In some embodiments, the one or more neoplastic cells are derived from a MSLN-expressing ovarian cancer, cervical cancer, pancreatic cancer, or lung cancer (e.g., lung adenocarcinoma). In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-MSLN antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non- responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[100] In some embodiments, the target antigen is FOLH1. In some embodiments, the one or more neoplastic cells are derived from a FOLH1-expressing prostate cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-FOLH1 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[101] In some embodiments, the target antigen is CDHB. In some embodiments, the one or more neoplastic cells are derived from a CDH6-expressing kidney cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-CDH6 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non- responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[102] In some embodiments, the target antigen is CEACAMS. In some embodiments, the one or more neoplastic cells are derived from a CEACAMS-expressing colorectal cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-CEACAMS antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[103] In some embodiments, the target antigen is CFC1B. In some embodiments, the one or more neoplastic cells are derived from a CFC1B-expressing pancreatic cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-CFC1B antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[104] In some embodiments, the target antigen is ENPP3. In some embodiments, the one or more neoplastic cells are derived from an ENPP3-expressing kidney cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-ENPP3 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[105] In some embodiments, the target antigen is FOLR1. In some embodiments, the one or more neoplastic cells are derived from a FOLR1-expressing ovarian cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-FOLR1 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[106] In some embodiments, the target antigen is HAVCR1. In some embodiments, the one or more neoplastic cells are derived from a HAVCR1-expressing kidney cancer or esophageal cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-HAVCR1 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[107] In some embodiments, the target antigen is KIT. In some embodiments, the one or more neoplastic cells are derived from a KIT-expressing kidney cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-KIT antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[108] In some embodiments, the target antigen is MET. In some embodiments, the one or more neoplastic cells are derived from a MET-expressing kidney cancer or esophageal cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-MET antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[109] In some embodiments, the target antigen is MUC16. In some embodiments, the one or more neoplastic cells are derived from a MUC16-expressing ovarian cancer, cervical cancer, or breast cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-MUC16 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[110] In some embodiments, the target antigen is SLC39A6. In some embodiments, the one or more neoplastic cells are derived from a SLC39A6-expressing breast cancer or prostate cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-SLC39A8 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[111] In some embodiments, the target antigen is SLC44A4. In some embodiments, the one or more neoplastic cells are derived from a SLC44A4-expressing prostate cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-SLC44A4 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[112] In some embodiments, the target antigen is STEAP1. In some embodiments, the one or more neoplastic cells are derived from a STEAP1-expressing prostate cancer. In some embodiments, the subject is non-responsive or poorly responsive to treatment with (a) an anti-STEAP1 antibody when administered alone and / or (b) a splicing modulator when administered alone. In some embodiments, the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

[113] In certain other aspects, the present disclosure provides methods of reducing or inhibiting growth of a tumor in a subject having or suspected of having a neoplastic disorder by administering to the subject a therapeutically effective amount and / or regimen of any one of the described ADCs or compositions.

[114] In some embodiments, treatment with the antibody-drug conjugate or composition induces bystander killing of neoplastic tumor cells which do not express a target antigen but are adjacent to neoplastic tumor cells which express a target antigen. In some embodiments, the tumor comprises one or more neoplastic cells which express a target antigen.

[115] In some embodiments, the target antigen is HER2. In some embodiments, the one or more neoplastic cells are derived from a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer (e.g., lung adenocarcinoma), uterine cancer (e.g., uterine serous endometrial carcinoma), osteosarcoma, or salivary duct carcinoma. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti- HER2 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[116] In some embodiments, the target antigen is CD138. In some embodiments, the one or more neoplastic cells are derived from a CD138-expressing multiple myeloma. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti- CD138 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[117] In some embodiments, the target antigen is EPHA2. In some embodiments, the one or more neoplastic cells are derived from an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-EPHA2 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[118] In some embodiments, the target antigen is MSLN. In some embodiments, the one or more neoplastic cells are derived from a MSLN-expressing ovarian cancer, cervical cancer, pancreatic cancer, or lung cancer (e.g., lung adenocarcinoma). In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti- MSLN antibody when administered alone and / or (b) a splicing modulator when administered alone.

[119] In some embodiments, the target antigen is FOLH1. In some embodiments, the one or more neoplastic cells are derived from a FOLH1-expressing prostate cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti- FOLH1 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[120] In some embodiments, the target antigen is CDHB. In some embodiments, the one or more neoplastic cells are derived from a CDH6-expressing kidney cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti- CDH6 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[121] In some embodiments, the target antigen is CEACAMS. In some embodiments, the one or more neoplastic cells are derived from a CEACAMS5-expressing colorectal cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-CEACAMS antibody when administered alone and / or (b) a splicing modulator when administered alone.

[122] In some embodiments, the target antigen is CFC1B. In some embodiments, the one or more neoplastic cells are derived from a CFC1B-expressing pancreatic cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti- CFC1B antibody when administered alone and / or (b) a splicing modulator when administered alone.

[123] In some embodiments, the target antigen is ENPP3. In some embodiments, the one or more neoplastic cells are derived from an ENPP3-expressing kidney cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti- ENPP3 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[124] In some embodiments, the target antigen is FOLR1. In some embodiments, the one or more neoplastic cells are derived from a FOLR1-expressing ovarian cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti- FOLR1 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[125] In some embodiments, the target antigen is HAVCR1. In some embodiments, the one or more neoplastic cells are derived from a HAVCR1-expressing kidney cancer or esophageal cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-HAVCR1 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[126] In some embodiments, the target antigen is KIT. In some embodiments, the one or more neoplastic cells are derived from a KIT-expressing kidney cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-KIT antibody when administered alone and / or (b) a splicing modulator when administered alone.

[127] In some embodiments, the target antigen is MET. In some embodiments, the one or more neoplastic cells are derived from a MET-expressing kidney cancer or esophageal cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-MET antibody when administered alone and / or (b) a splicing modulator when administered alone.

[128] In some embodiments, the target antigen is MUC16. In some embodiments, the one or more neoplastic cells are derived from a MUC16-expressing ovarian cancer, cervical cancer, or breast cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-MUC16 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[129] In some embodiments, the target antigen is SLC39A6. In some embodiments, the one or more neoplastic cells are derived from a SLC39A6-expressing breast cancer or prostate cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-SLC39A6 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[130] In some embodiments, the target antigen is SLC44A4. In some embodiments, the one or more neoplastic cells are derived from a SLC44A4-expressing prostate cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-SLC44A4 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[131] In some embodiments, the target antigen is STEAP1. In some embodiments, the one or more neoplastic cells are derived from a STEAP1-expressing prostate cancer. In some embodiments, the tumor is resistant or refractory to treatment with (a) an anti-STEAP1 antibody when administered alone and / or (b) a splicing modulator when administered alone.

[132] In still other aspects, the present disclosure provides methods of determining whether a subject having or suspected of having a neoplastic disorder will be responsive to treatment with any one of the described ADCs or compositions by providing a biological sample from the subject and contacting the biological sample with the ADC or composition. In some embodiments, the biological sample is a tumor sample. In some embodiments, the tumor sample is a tumor biopsy or blood sample. In some embodiments, the blood sample is selected from blood, a blood fraction, or a cell obtained from the blood or blood fraction. In some embodiments, the subject has one or more neoplastic cells which express a target antigen. In some embodiments, the target antigen is HER2. In some embodiments, the one or more neoplastic cells are derived from a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer (e.g., lung adenocarcinoma), uterine cancer (e.g., uterine serous endometrial carcinoma), osteosarcoma, or salivary duct carcinoma. In some embodiments, the target antigen is CD138. In some embodiments, the one or more neoplastic cells are derived from a CD138-expressing multiple myeloma. In some embodiments, the target antigen is EPHA2. In some embodiments, the one or more neoplastic cells are derived from an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer. In some embodiments, the target antigen is MSLN. In some embodiments, the one or more neoplastic cells are derived from a MSLN-expressing ovarian cancer, cervical cancer, pancreatic cancer, or lung cancer (e.g., lung adenocarcinoma). In some embodiments, the target antigen is FOLH1. In some embodiments, the one or more neoplastic cells are derived from a FOLH1-expressing prostate cancer. In some embodiments, the target antigen is CDH6. In some embodiments, the one or more neoplastic cells are derived from a CDH6- expressing kidney cancer. In some embodiments, the target antigen is CEACAMS. In some embodiments, the one or more neoplastic cells are derived from a CEACAMS5- expressing colorectal cancer. In some embodiments, the target antigen is CFC1B. In some embodiments, the one or more neoplastic cells are derived from a CFC1B- expressing pancreatic cancer. In some embodiments, the target antigen is ENPP3. In some embodiments, the one or more neoplastic cells are derived from an ENPP3- expressing kidney cancer. In some embodiments, the target antigen is FOLR1. In some embodiments, the one or more neoplastic cells are derived from a FOLR1- expressing ovarian cancer. In some embodiments, the target antigen is HAVCR1. In some embodiments, the one or more neoplastic cells are derived from a HAVCR1- expressing kidney cancer or esophageal cancer. In some embodiments, the target antigen is KIT. In some embodiments, the one or more neoplastic cells are derived from a KIT-expressing kidney cancer. In some embodiments, the target antigen is MET. In some embodiments, the one or more neoplastic cells are derived from a MET- expressing kidney cancer or esophageal cancer. In some embodiments, the target antigen is MUC186. In some embodiments, the one or more neoplastic cells are derived from a MUC16-expressing ovarian cancer, cervical cancer, or breast cancer. In some embodiments, the target antigen is SLC39A6. In some embodiments, the one or more neoplastic cells are derived from a SLC39A6-expressing breast cancer or prostate cancer. In some embodiments, the target antigen is SLC44A4. In some embodiments, the one or more neoplastic cells are derived from a SLC44A4-expressing prostate cancer. In some embodiments, the target antigen is STEAP1. In some embodiments, the one or more neoplastic cells are derived from a STEAP1-expressing prostate cancer.

[133] Further provided herein, in various embodiments, are pharmaceutical compositions comprising an ADC and a pharmaceutically acceptable diluent, carrier, and / or excipient. Methods of producing the described ADC compounds and compositions are also disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[134] FIG. 1 shows dose response of exemplary payload compounds in a competitive binding assay. Nuclear extracts from 293F cells overexpressing wild type flag-tagged SF3B1 were immunoprecipitated with an anti-SF3B1 antibody and scintillation proximity assay (SPA) bead cocktail. Binding reactions contained the antibody-bead mixture and increasing concentrations of compound, followed by competition with an *H-labelled pladienolide B (PB) probe. The y-axis represents the percent change (% response) of specific binding relative to the DMSO control (0%). Data are represented as mean + standard deviation (SD).

[135] FIG. 2 shows modulation of splicing by exemplary payload compounds in an in vitro splicing assay. Nuclear extracts from Hela S3 cells were incubated with Ad2.2 pre-mRNA and increasing concentrations of compound, followed by quantification of splicing modulation via RT-PCR. The Ad2.2 sequence is derived from the adenoviral Ad2 pre-mRNA substrate with modifications around the branch point sequence. The y- axis represents the percent change (% response) of splicing relative to the DMSO control (0%). Data are represented as mean + SD.

[136] FIG. 3 shows viability dose response of exemplary payload compounds in HER2-amplified breast cancer cells (HCC1954). Cells were incubated with compound for 144 hours (6 days) and viability was read in CellTiter-Glo® reagent. Data are represented as mean + SD.

[137] FIG. 4 shows the results of a cell binding assay. Binding of exemplary HER2- ADCs to JIMT1 cells was assessed by flow cytometry. Mean fluorescence intensity values were measured to determine binding of conjugates, followed by PE-labelled secondary. Data are represented as mean + SD.

[138] FIG. 5A shows viability dose response of exemplary HER2-ADCs in HER2- amplified breast cancer cells (HCC1954). FIG. 5B shows viability dose response of exemplary HER2-ADCs in HER2-amplified gastric cancer cells (N87). FIG. 5C shows viability dose response of exemplary HER2-ADCs in HER2-amplified breast cancer cells (SKBR3). Cells were incubated with conjugates for 144 hours (6 days) and viability was read in CellTiter-Glo® reagent. Data are represented as mean + SD.

[139] FIG. 6 shows viability dose response of exemplary HER2-ADCs in non-HER2 expressing breast cancer cells (MCF7). Cells were incubated with conjugates for 144 hours (6 days) and viability was read in CellTiter-Glo® reagent. Data are represented as mean + SD.

[140] FIG. 7 shows the results of a SLC25A19 splicing assay in HER2-amplified breast cancer cells (HCC1954). Cells were incubated with conjugates for 24 hours and splicing of SLC25A 19 transcript was measured in a real time qPCR reaction with a specific Tagman primer-probe set. The y-axis represents the percent (%) response relative to the DMSO control (0%). Data are represented as mean + SD.

[141] FIG. 8 shows the results of a bystander killing assay. H1568 cells overexpressing HER2 (target-positive) or H1568 cells tagged with luciferase (target- negative) plated either alone or incubated together in co-culture for 144 hours (6 days) were treated with exemplary HER2-ADCs. Plates were read with OneGlo® reagent. The y-axis represents the percent (%) response relative to the PBS control (100%). Data are represented as mean + SD.

[142] FIG. 9 shows tumor growth kinetics for each group of HCC1954-implanted CB17-SCID mice treated with a single intravenous dose of an exemplary HER2-ADC or corresponding dose-matched payload (6-10 animals per group). Tumor volumes were measured twice weekly after treatment. Data are represented as mean + standard error of the mean (SEM).

[143] FIG. 10 shows viability dose response of exemplary CD138-ADCs in a CD138- expressing multiple myeloma cell line. MOLP8 cells were incubated with conjugates for 144 hours (6 days) and viability was read in CellTiter-Glo® reagent. Data are represented as mean + SD.

[144] FIG. 11 shows viability dose response of exemplary EPH2A-ADCs in an EPHA2- expressing prostate cancer cell line. PC3 cells were incubated with conjugates for 144 hours (6 days) and viability was read in CellTiter-Glo® reagent. Data are represented as mean + SD.

[145] FIG. 12A and FIG. 12B show the results of an in vitro stability assay for an exemplary anti-HER2 ADC, AB185-ADL1-D1. The y-axis represents concentration of total antibody (FIG. 12A) and conjugated (intact) payload (FIG. 12B); the x-axis represents time as measured in hours at 37°C.

[146] FIG. 13 shows plasma concentrations of an exemplary ant-HER2 ADC, AB185- ADL1-D1, following a single intravenous dose in CD17-SCID N87 tumor-bearing mice.

[147] FIG. 14 shows a schematic diagram of an exemplary RNA sequencing and protein ligandome experiment.

[148] FIG. 15 shows a schematic diagram of an exemplary T-cell priming experiment.

[149] FIG. 16 shows the results of a FACS analysis. Monocytes were isolated from peripheral blood mononuclear cells (PBMC) and were induced to differentiate into dendritic cells (DC) through culturing in a cytokine cocktail. FACS was performed to validate the maturation of DC from monocytes.

[150] FIG. 17A-D show the results of an ELISpot assay. FIG. 17A shows ELISpot plates indicating Neoantigen 1 priming of CD8+ T-cell activation. Stimulation of CD8+ T-cells was monitored by secretion of IFNy. FIG. 17B shows quantification of IFNy spots (spot number) in Neoantigen 1 ELISpot plates (FIG. 17A). FIG. 17C shows ELISpot plates indicating Neoantigen 3 priming of CD8+ T-cell activation. Stimulation of CD8+ T-cells was monitored by secretion of IFNy. FIG. 17D shows quantification of IFNy spots (fold change) in Neoantigen 3 ELISpot plates (FIG. 17C).

[151] FIG. 18 shows a plot comparing splicing potency (IC50 qPCR) against cellular potency (GI50 CTG) for exemplary anti-HER2 ADCs in HCC1954 breast cancer cells. Values shown are sized by cell lethality and shaded by depth of alternative splicing response.

[162] FIG. 19 shows a plot comparing splicing potency (IC50 gPCR) against cellular potency (GI50 CTG) for exemplary anti-HER2 ADCs in N87 gastric cancer cells. Values shown are sized by cell lethality and shaded by depth of alternative splicing response.

[153] FIG. 20 shows a plot comparing potency and lethality of exemplary anti-HER2 ADCs (in HCC1954 breast cancer cells) against stability and permeability of corresponding payloads. Values shown are sized by payload stability and shaded by payload permeability.

[154] FIG. 21 shows tumor growth kinetics for each group of N87-implanted CB17- SCID mice treated intravenously with vehicle or 10 mg / kg trastuzumab, TDM1, or an exemplary HER2-ADC Q7D for 2 cycles (N=8 per group). Data are represented as mean = standard error of the mean (SEM) (mm?3).

[155] FIG. 22 shows body weight change for each group of N87-implanted CB17-SCID mice treated intravenously with vehicle or 10 mg / kg trastuzumab, TDM1, or an exemplary HER2-ADC Q7D for 2 cycles (N=8 per group). Data are represented as mean + standard error of the mean (SEM) (%).

[166] FIG. 23 shows tumor growth kinetics (left) and body weight change (right) for each group of N87-implanted CB17-SCID mice treated intravenously with vehicle or 10 mg / kg trastuzumab, TDM1, or an exemplary HER2-ADC Q7D for 2 cycles (N=8 per group). Data are represented as mean + SEM (tumor volume, mm?) or mean + SEM (body weight, %).

[157] FIG. 24A-24D show pharmacodynamics (PD) modulation of mRNA junctions in N87-implanted CB17-SCID mice treated intravenously with vehicle or 10 mg / kg trastuzumab, TDM1, or an exemplary HER2-ADC Q7D for 2 cycles. RT-qPCR of FBXWS5 (mature mRNA transcript) was monitored and is shown in FIG. 24A and FIG. 24C. RT-gPCR of TAOK1 (neojunction transcript) was monitored and is shown in FIG. 24B and FIG. 24D. Animals (N=4 per group) were collected at either 48 hours (FIG. 24A and FIG. 24B) or at the times indicated (FIG. 24C and FIG. 24D). Tumors were isolated for RNA extraction and RT-qPCR.

[158] FIG. 25 shows a schematic diagram of an exemplary target indication analysis.

[169] FIG. 26 shows an exemplary bioconjugation scheme for preparation of ADCs using splicing modulators. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[160] The disclosed compositions and methods may be understood more readily by reference to the following detailed description taken in connection with the accompanying figures, which form a part of this disclosure.

[161] Throughout this text, the descriptions refer to compositions and methods of using the compositions. Where the disclosure describes or claims a feature or embodiment associated with a composition, such a feature or embodiment is equally applicable to the methods of using the composition. Likewise, where the disclosure describes or claims a feature or embodiment associated with a method of using a composition, such a feature or embodiment is equally applicable to the composition.

[162] When a range of values is expressed, it includes embodiments using any particular value within the range. Further, reference to values stated in ranges includes each and every value within that range. All ranges are inclusive of their endpoints and combinable. When values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. Reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. The use of “or” will mean “and / or” unless the specific context of its use dictates otherwise. All references cited herein are incorporated by reference for any purpose. Where a reference and the specification conflict, the specification will control.

[163] Itis to be appreciated that certain features of the disclosed compositions and methods, which are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosed compositions and methods that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Definitions

[164] Various terms relating to aspects of the description are used throughout the specification and claims. Such terms are to be given their ordinary meaning in the art unless otherwise indicated. Other specifically defined terms are to be construed in a manner consistent with the definitions provided herein.

[165] As used herein, the singular forms “a,” “an,” and “the” include plural forms unless the context clearly dictates otherwise.

[166] The terms "about" or "approximately" in the context of numerical values and ranges refers to values or ranges that approximate or are close to the recited values or ranges such that the embodiment may perform as intended, such as having a desired amount of nucleic acids or polypeptides in a reaction mixture, as is apparent to the skilled person from the teachings contained herein. In some embodiments, about means plus or minus 10% of a numerical amount.

[167] The terms “antibody-drug conjugate,” “antibody conjugate,” “conjugate,” “‘immunoconjugate,” and “ADC” are used interchangeably, and refer to one or more therapeutic compounds (e.g., a splicing modulator) that is linked to one or more antibodies or antigen binding fragments and is defined by the generic formula: Ab-(L-D), (Formula I), wherein Ab = an antibody or antigen binding fragment, L = a linker moiety, D = a drug moiety (e.g., a splicing modulator drug moiety), and p = the number of drug moieties per antibody or antigen binding fragment. An ADC comprising a splicing modulator drug moiety may also be referred to herein more specifically as a “splicing modulator-loaded antibody” or a “SMLA.” In ADCs comprising a splicing modulator drug moiety, “p” refers to the number of splicing modulator compounds linked to the antibody or antigen binding fragment. In some embodiments, the linker L can include a cleavable moiety between the antibody or antigen binding fragment and the therapeutic compound. In some embodiments, the linker L can include a cleavable moiety that can be attached to either or both the antibody or antigen binding fragment and therapeutic compound by spacer unit(s). In some embodiments, when a spacer unit attaches the cleavable moiety to the therapeutic compound, it is a self-immolative spacer unit. In other embodiments, the linker L does not include a cleavable moiety, and is a non- cleavable linker. In some embodiments, the linker L can include at least one spacer unit that can directly attach to the antibody or antigen binding fragment and to the therapeutic compound. Exemplary cleavable and non-cleavable linkers are described and exemplified herein.

[168] The term "antibody" is used in the broadest sense to refer to an immunoglobulin molecule that recognizes and specifically binds to a target, such as a protein, polypeptide, carbohydrate, polynucleotide, lipid, or combinations of the foregoing through at least one antigen recognition site within the variable region of the immunoglobulin molecule. The heavy chain of an antibody is composed of a heavy chain variable domain (Vx) and a heavy chain constant region (Cu). The light chain is composed of a light chain variable domain (VL) and a light chain constant domain (Cy). For the purposes of this application, the mature heavy chain and light chain variable domains each comprise three complementarity determining regions (CDR1, CDR2 and CDR3) within four framework regions (FR1, FR2, FR3, and FR4) arranged from N- terminus to C-terminus: FR1, CDR1, FR2, CDR2, FR3, CDRS, and FR4. An "antibody" can be naturally occurring or man-made, such as monoclonal antibodies produced by conventional hybridoma technology. The term “antibody” includes full-length monoclonal antibodies and full-length polyclonal antibodies, as well as antibody fragments such as Fab, Fab’, F(ab’)z, Fv, and single chain antibodies. An antibody can be any one of the five major classes of immunoglobulins: IgA, 1gD, IgE, IgG, and IgM, or subclasses thereof (e.g., isotypes 1gG1, 1gG2, 19G3, IgG4). The term further encompasses human antibodies, chimeric antibodies, humanized antibodies and any modified immunoglobulin molecule containing an antigen recognition site, so long as it demonstrates the desired biological activity (e.g., binds the target antigen, internalizes within a target-antigen expressing cell).

[169] The term "monoclonal antibody," as used herein, refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic epitope. In contrast, conventional (polyclonal) antibody preparations typically include a multitude of antibodies directed against (or specific for) different epitopes. The modifier “monoclonal” indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies, and is not to be construed as requiring production of the antibody by any particular method. For example, the monoclonal antibodies to be used in accordance with the present disclosure may be made by the hybridoma method first described by Kohler et al. (1975) Nature 256.495, or may be made by recombinant DNA methods (see, e.g., U.S. Pat. No. 4,816,567). Monoclonal antibodies may also be isolated from phage antibody libraries using the techniques described in Clackson et al. (1991) Nature 352:624-8, and Marks et al. (1991) J Mol Biol. 222:581-97, for example.

[170] The monoclonal antibodies described herein specifically include "chimeric" antibodies, in which a portion of the heavy and / or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they specifically bind the target antigen and / or exhibit the desired biological activity.

[171] The term “human antibody,” as used herein, refers an antibody produced by a human or an antibody having an amino acid sequence of an antibody produced by a human.

[172] The term “chimeric antibody,” as used herein, refers to antibodies wherein the amino acid sequence of the immunoglobulin molecule is derived from two or more species. In some instances, the variable regions of both heavy and light chains correspond to the variable regions of antibodies derived from one species with the desired specificity, affinity, and activity while the constant regions are homologous to antibodies derived from another species (e.g., human) to minimize an immune response in the latter species.

[173] As used herein, the term "humanized antibody" refers to forms of antibodies that contain sequences from non-human (e.g., murine) antibodies as well as human antibodies. Such antibodies are chimeric antibodies which contain minimal sequence derived from non-human immunoglobulin. In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the hypervariable loops correspond to those of a non-human immunoglobulin and all or substantially all of the framework (FR) regions are those of a human immunoglobulin sequence. The humanized antibody optionally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin. The humanized antibody can be further modified by the substitution of residues, either in the Fv framework region and / or within the replaced non-human residues to refine and optimize antibody specificity, affinity, and / or activity.

[174] The term "antigen binding fragment" or "antigen binding portion" of an antibody, as used herein, refers to one or more fragments of an antibody or protein that retain the ability to specifically bind to an antigen (e.g., HER2, CD138, EPHA2, MSLN, FOLH1, CDH8, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A8, SLC44A4, STEAP1). Antigen binding fragments may also retain the ability to internalize into an antigen-expressing cell. In some embodiments, antigen binding fragments also retain immune effector activity. It has been shown that fragments of a full-length antibody can perform the antigen binding function of a full-length antibody. Examples of binding fragments encompassed within the term "antigen binding fragment" or "antigen binding portion" of an antibody include (i) a Fab fragment, a monovalent fragment consisting of the Vi, Vu, Ci, and C1 domains; (ii) a F(ab')2 fragment, a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) a Fd fragment consisting of the Vy and Cw1 domains; (iv) a Fv fragment consisting of the Vi. and Vy domains of a single arm of an antibody; (v) a dAb fragment, which comprises a single variable domain, e.g., a Vy domain (see, e.g., Ward et al. (1989) Nature 341:544- 6; and Intl. Pub. No. WO 1990 / 005144); and (vi) an isolated complementarity determining region (CDR). Furthermore, although the two domains of the Fv fragment, Vi and Vu, are coded for by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the Vi and Vi regions pair to form monovalent molecules (known as single chain Fv (scFv)). See, e.g., Bird et al. (1988) Science 242:423-6; and Huston et al. (1988) Proc Natl Acad Sci. USA 85:5879-83. Such single chain antibodies are also intended to be encompassed within the term "antigen binding fragment" or “antigen binding portion" of an antibody, and are known in the art as an exemplary type of binding fragment that can internalize into cells upon binding (see, e.g., Zhu et al. (2010) 9:2131-41; He et al. (2010) J Nucl Med. 51:427-32; and Fitting et al. (2015) MAbs 7:390-402). In certain embodiments, scFv molecules may be incorporated into a fusion protein. Other forms of single chain antibodies, such as diabodies are also encompassed. Diabodies are bivalent, bispecific antibodies in which Vi and Vi. domains are expressed on a single polypeptide chain, but using a linker that is too short to allow for pairing between the two domains on the same chain, thereby forcing the domains to pair with complementary domains of another chain and creating two antigen binding sites (see e.g., Holliger et al. (1993) Proc Natl Acad Sci. USA 90:6444-8; and Poljak et al. (1994) Structure 2:1121-3). Antigen binding fragments are obtained using conventional techniques known to those of skill in the art, and the binding fragments are screened for utility (e.g., binding affinity, internalization) in the same manner as are intact antibodies. Antigen binding fragments may be prepared by cleavage of the intact protein, e.g., by protease or chemical cleavage.

[175] ‘“Internalizing” as used herein in reference to an antibody or antigen binding fragment refers to an antibody or antigen binding fragment that is capable of being taken through the cell’s lipid bilayer membrane to an internal compartment (i.e., “‘internalized”) upon binding to the cell, preferably into a degradative compartment in the cell. For example, an internalizing anti-HER2 antibody is one that is capable of being taken into the cell after binding to HER2 on the cell membrane. In some embodiments, the antibody or antigen binding fragment used in the ADCs disclosed herein targets a cell surface antigen (e.g., HER2) and is an internalizing antibody or internalizing antigen binding fragment (i.e., the ADC transfers through the cellular membrane after antigen binding). In some embodiments, the internalizing antibody or antigen binding fragment binds a receptor on the cell surface. An internalizing antibody or internalizing antigen binding fragment that targets a receptor on the cell membrane may induce receptor- mediated endocytosis. In some embodiments, the internalizing antibody or internalizing antigen binding fragment is taken into the cell via receptor-mediated endocytosis.

[176] “Non-internalizing” as used herein in reference to an antibody or antigen binding fragment refers to an antibody or antigen binding fragment that remains at the cell surface upon binding to the cell. In some embodiments, the antibody or antigen binding fragment used in the ADCs disclosed herein targets a cell surface antigen and is a non- internalizing antibody or non-internalizing antigen binding fragment (i.e., the ADC remains at the cell surface and does not transfer through the cellular membrane after antigen binding). In some embodiments, the non-internalizing antibody or antigen binding fragment binds a non-internalizing receptor or other cell surface antigen. Exemplary non-internalizing cell surface antigens include but are not limited to CA125 and CEA, and antibodies that bind to non-internalizing antigen targets are also known in the art (see, e.g., Bast et al. (1981) J Clin Invest. 68(5):1331-7; Scholler and Urban (2007) Biomark Med. 1(4):513-23; and Boudousq et al. (2013) PLoS One 8(7):e69613).

[177] The term “human epidermal growth factor receptor 2,” “HER2,” or “HER2 / NEU,” as used herein, refers to any native form of human HER2. The term encompasses full- length HER2 (e.g., UniProt Reference Sequence: P04626; SEQ ID NO:31), as well as any form of human HER2 that may result from cellular processing. The term also encompasses functional variants or fragments of human HERZ, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human HER?2 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). HER2 can be isolated from human, or may be produced recombinantly or by synthetic methods.

[178] The term “anti-HER2 antibody” or “antibody that binds to HER2” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to HER2, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to HER2. U.S. Pat. No. 5,821,337 provides and is incorporated herein by reference for exemplary HER2-binding sequences, including exemplary anti-HER2 antibody sequences. In some embodiments, the anti-HER2 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment. Trastuzumab (U.S. Pat. No. 5,821,337; Molina et al. (2001) Cancer Res. 61(12):4744-9) is an exemplary anti-human HER2 antibody.

[179] The term “syndecan-1,” “SDC1,” or “CD138,” as used herein, refers to any native form of human CD138. The term encompasses full-length CD138 (e.g., UniProt Reference Sequence: P18827; SEQ ID NO:32), as well as any form of human CD138 that may result from cellular processing. The term also encompasses functional variants or fragments of human CD 138, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human CD138 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). CD138 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[180] The term "anti-CD138 antibody” or “antibody that binds to CD138" refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to CD138, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to CD138. In some embodiments, the anti-CD138 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment. B-B4 (Tassone et al. (2004) Blood 104:3688-96) is an exemplary anti-human CD138 antibody.

[181] The term “ephrin type-A receptor 2” or "EPHA2,” as used herein, refers to any native form of human EPHA2. The term encompasses full-length EPHA2 (e.g., UniProt Reference Sequence: P29317; SEQ ID NO:33), as well as any form of human EPHA2 that may result from cellular processing. The term also encompasses functional variants or fragments of human EPHA2, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human EPHA2 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). EPHA2 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[182] The term "anti-EPHA2 antibody" or “antibody that binds to EPHA2” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to EPHA2, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to EPHA2. WO 2007 / 030642 provides and is incorporated herein by reference for exemplary EPHA2-binding sequences, including exemplary anti- EPHAZ2 antibody sequences. In some embodiments, the anti-EPHA2 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment. 1C1 (WO 2007 / 030642; Jackson et al. (2008) Cancer Res. 68(22): 9367-74) is an exemplary anti-human EPHAZ2 antibody.

[183] The term “mesothelin” or “MSLN,” as used herein, refers to any native form of human MSLN. The term encompasses full-length MSLN (e.g., UniProt Reference Sequence: Q13421; SEQ ID NO:43), as well as any form of human MSLN that may result from cellular processing. The term also encompasses functional variants or fragments of human MSLN, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human MSLN (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). MSLN can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[184] The term "anti-MSLN antibody" or “antibody that binds to MSLN" refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to MSLN, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to MSLN. WO 2011 / 074621 provides and is incorporated herein by reference for exemplary MSLN-binding sequences, including exemplary anti- MSLN antibody sequences. In some embodiments, the anti-MSLN antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment. 11-25, IC14-30, IC7-4, IC17-35 and 2-9 are exemplary anti-human MSLN antibodies.

[185] The term “glutamate carboxypeptidase 2” or “FOLH1,” as used herein, refers to any native form of human FOLH1. The term encompasses full-length FOLH1 (e.g., UniProt Reference Sequence: Q04609; SEQ ID NO:44), as well as any form of human FOLH1 that may result from cellular processing. The term also encompasses functional variants or fragments of human FOLH1, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human FOLH1 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). FOLH1 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[186] The term "anti-FOLH1 antibody" or “antibody that binds to FOLH1" refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to FOLH1, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to FOLH1. WO 2019 / 012260 and WO 2017 / 212250 provide and are incorporated herein by reference for exemplary FOLH1-binding sequences, including exemplary anti-FOLH1 antibody sequences. In some embodiments, the anti- FOLH1 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment. J591 (deimmunized) is an exemplary anti-human FOLH1 antibody.

[187] The term “cadherin-6" or “CDH8,” as used herein, refers to any native form of human CDH6. The term encompasses full-length CDH6 (e.g., UniProt Reference Sequence: P55285; SEQ ID NO:45), as well as any form of human CDH6 that may result from cellular processing. The term also encompasses functional variants or fragments of human CDHB8, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human CDH (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). CDH6 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[188] The term "anti-CDH®6 antibody" or “antibody that binds to CDH" refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to CDH6, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to CDH6. WO 2018 / 185618 provides and is incorporated herein by reference for exemplary CDH6-binding sequences, including exemplary anti- CDHB6 antibody sequences. In some embodiments, the anti-CDH6 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[189] The term “carcinoembryonic antigen-related cell adhesion molecule 5” or “CEACAMS,” as used herein, refers to any native form of human CEACAMS. The term encompasses full-length CEACAMS (e.g., UniProt Reference Sequence: P06731; SEQ ID NO:48), as well as any form of human CEACAMS that may result from cellular processing. The term also encompasses functional variants or fragments of human CEACAMS, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human CEACAMS (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild- type protein only). CEACAMS can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[190] The term "anti-CEACAMS antibody" or “antibody that binds to CEACAMS5” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to CEACAMS, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to CEACAMS. US 2015 / 0125386 provides and is incorporated herein by reference for exemplary CEACAMS5-binding sequences, including exemplary anti-CEACAMS antibody sequences. In some embodiments, the anti-CEACAMS antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment. hMN14 is an exemplary anti-human CEACAMS antibody.

[191] The term “cryptic family protein 1B” or “CFC1B,” as used herein, refers to any native form of human CFC1B. The term encompasses full-length CFC1B (e.g., UniProt Reference Sequence: POCG36: SEQ ID NO:47), as well as any form of human CFC1B that may result from cellular processing. The term also encompasses functional variants or fragments of human CFC1B, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human CFC1B (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). CFC1B can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[192] The term "anti-CFC1B antibody" or “antibody that binds to CFC1B” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to CFC1B, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to CFC1B. WO 2002 / 088170 provides and is incorporated herein by reference for exemplary CFC1B-binding sequences, including exemplary anti- CFC1B antibody sequences. In some embodiments, the anti-CFC1B antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[193] The term “ectonucleotide pyrophosphatase / phosphodiesterase family member 3” or “ENPP3,” as used herein, refers to any native form of human ENPP3. The term encompasses full-length ENPP3 (e.g., UniProt Reference Sequence: 014638; SEQ ID NO:48), as well as any form of human ENPP3 that may result from cellular processing. The term also encompasses functional variants or fragments of human ENPP3, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human ENPP3 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). ENPP3 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[194] The term "anti-ENPP3 antibody" or “antibody that binds to ENPP3” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to ENPP3, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to ENPP3. Donate et al. ((2016) Clin Cancer Res. 22(8):1989-99) provides and is incorporated herein by reference for exemplary ENPP3- binding sequences, including exemplary anti-ENPP3 antibody sequences. In some embodiments, the anti-ENPP3 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[195] The term “folate receptor alpha” or “FOLR1,” as used herein, refers to any native form of human FOLR1. The term encompasses full-length FOLR1 (e.g., UniProt Reference Sequence: P15328; SEQ ID NO:49), as well as any form of human FOLR1 that may result from cellular processing. The term also encompasses functional variants or fragments of human FOLR1, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human FOLR1 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). FOLR1 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[196] The term "anti-FOLR1 antibody" or “antibody that binds to FOLR1" refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to FOLR1, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to FOLR1. WO 2005 / 080431 and Coney et al. ((1991) Cancer Res. 51(22):6125-32) provide and are incorporated herein by reference for exemplary FOLR1-binding sequences, including exemplary anti-FOLR1 antibody sequences. In some embodiments, the anti-FOLR1 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment. Farletuzumab and MOv19 are exemplary anti-human FOLR1 antibodies.

[197] The term “hepatitis A virus cellular receptor 1” or “HAVCR1,” as used herein, refers to any native form of human HAVCR1. The term encompasses full-length HAVCR1 (e.g., UniProt Reference Sequence: Q96D42; SEQ ID NO:50), as well as any form of human HAVCR1 that may result from cellular processing. The term also encompasses functional variants or fragments of human HAVCR1, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human HAVCR1 (i.e, variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). HAVCR1 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[198] The term "anti-HAVCR1 antibody" or “antibody that binds to HAVCR1" refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to HAVCR1, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to HAVCR1. Thomas et al. ((2016) Mol Cancer Ther. 15(12):2946-54) provides and is incorporated herein by reference for exemplary HAVCR1-binding sequences, including exemplary anti-HAVCR1 antibody sequences. In some embodiments, the anti-HAVCR1 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[199] The term “mast / stem cell growth factor receptor Kit” or “KIT,” as used herein, refers to any native form of human KIT. The term encompasses full-length KIT (e.g., UniProt Reference Sequence: P10721; SEQ ID NO:51), as well as any form of human KIT that may result from cellular processing. The term also encompasses functional variants or fragments of human KIT, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human KIT (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). KIT can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[200] The term "anti-KIT antibody” or “antibody that binds to KIT” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to KIT, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to KIT. Shi et al. (2016) Proc Natl Acad Sci USA 113(33):E4784-93) and Abrams et al. ((2018) Clin Cancer Res. 24(17):4297-308) provide and are incorporated herein by reference for exemplary KIT-binding sequences, including exemplary anti-KIT antibody sequences. In some embodiments, the anti-KIT antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[201] The term “hepatocyte growth factor receptor’ or “MET,” as used herein, refers to any native form of human MET. The term encompasses full-length MET (e.g., UniProt Reference Sequence: P08581; SEQ ID NO:52), as well as any form of human MET that may result from cellular processing. The term also encompasses functional variants or fragments of human MET, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human MET (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). MET can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[202] The term "anti-MET antibody" or “antibody that binds to MET" refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to MET, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to MET. Yang et al. ((2019) Acta Pharmacol Sin.) provides and is incorporated herein by reference for exemplary MET-binding sequences, including exemplary anti-MET antibody sequences. In some embodiments, the anti- MET antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[203] The term “mucin-16" or “MUC16,” as used herein, refers to any native form of human MUC16. The term encompasses full-length MUC16 (e.g., UniProt Reference Sequence: Q8WXI7; SEQ ID NO:53), as well as any form of human MUC16 that may result from cellular processing. The term also encompasses functional variants or fragments of human MUC 18, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human MUC16 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). MUC186 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[204] The term "anti-MUC16 antibody" or “antibody that binds to MUC186” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to MUC16, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to MUC16. Liu et al. (2016) Ann Oncol. 27(11):2124-30) provides and is incorporated herein by reference for exemplary MUC 16-binding sequences, including exemplary anti-MUC16 antibody sequences. In some embodiments, the anti-MUC 16 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[205] The term “zinc transporter ZIP6” or “SLC39A8,” as used herein, refers to any native form of human SLC39A6. The term encompasses full-length SLC39A6 (e.g., UniProt Reference Sequence:Q13433; SEQ ID NO:54), as well as any form of human SLC39A6 that may result from cellular processing. The term also encompasses functional variants or fragments of human SLC39A8, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human SLC39A6 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). SLC39A6 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[206] The term "anti-SLC39A6 antibody" or “antibody that binds to SLC39A6" refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to SLC39A6, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to SLC39A6. Sussman et al. (2014) Mol Cancer Ther. 13(12):2991-3000) provides and is incorporated herein by reference for exemplary SLC39A6-binding sequences, including exemplary anti-SLC39A6 antibody sequences. In some embodiments, the anti-SLC39A8 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[207] The term “choline transporter-like protein 4” or “SLC44A4,” as used herein, refers to any native form of human SLC44A4. The term encompasses full-length SLC44A4 (e.g., UniProt Reference Sequence: Q53GD3; SEQ ID NO:55), as well as any form of human SLC44A4 that may result from cellular processing. The term also encompasses functional variants or fragments of human SLC44A4, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human SLC44A4 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). SLC44A4 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[208] The term "anti-SLC44A4 antibody" or “antibody that binds to SLC44A4” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to SLC44A4, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to SLC44A4. Mattie et al. (2016) Mol Cancer Ther. 15(11):2679-87) provides and is incorporated herein by reference for exemplary SLC44A4-binding sequences, including exemplary anti-SLC44A4 antibody sequences. In some embodiments, the anti-SLC44A4 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[209] The term “metalloreductase STEAP1” or “STEAP1,” as used herein, refers to any native form of human STEAP1. The term encompasses full-length STEAP1 (e.g., UniProt Reference Sequence: QOUHES; SEQ ID NO:56), as well as any form of human STEAP1 that may result from cellular processing. The term also encompasses functional variants or fragments of human STEAP1, including but not limited to splice variants, allelic variants, and isoforms that retain one or more biologic functions of human STEAP1 (i.e., variants and fragments are encompassed unless the context indicates that the term is used to refer to the wild-type protein only). STEAP1 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[210] The term "anti-STEAP1 antibody" or “antibody that binds to STEAP1” refers to any form of antibody or fragment thereof that binds, e.g., specifically binds, to STEAP1, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they bind, e.g., specifically bind, to STEAP1. WO 2008 / 052187 provides and is incorporated herein by reference for exemplary STEAP1-binding sequences, including exemplary anti-STEAP1 antibody sequences. In some embodiments, the anti-STEAP1 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment.

[211] As used herein, the term "specific," “specifically binds," and "binds specifically" refers to a binding reaction between an antibody or antigen binding fragment (e.g., an anti-HER2 antibody) and a target antigen (e.g., HER2) in a heterogeneous population of proteins and other biologics. Antibodies can be tested for specificity of binding by comparing binding to an appropriate antigen to binding to an irrelevant antigen or antigen mixture under a given set of conditions. If the antibody binds to the appropriate antigen with at least 2, 5, 7, and preferably 10 or more times more affinity than to the irrelevant antigen or antigen mixture, then it is considered to be specific. A “specific antibody” or a “target-specific antibody” is one that only binds the target antigen (e.g., HER2), but does not bind (or exhibits minimal binding) to other antigens. In certain embodiments, an antibody or antigen binding fragment that specifically binds a target antigen (e.g., HER2) has a Kp of less than 1x10 M, less than 1x107 M, less than 1x10® M, less than 1x10 M, less than 1x10 M, less than 1x10" M, less than 1x10-'2 M, or less than 1x10" M. In certain embodiments, the Kp is 1 pM to 500 pM. In some embodiments, the Kp is between 500 pM to 1 uM, 1 uM to 100 nM, or 100 mM to 10 nM.

[212] The term “epitope” refers to the portion of an antigen capable of being recognized and specifically bound by an antibody. When the antigen is a polypeptide, epitopes can be formed from contiguous amino acids or noncontiguous amino acids juxtaposed by tertiary folding of the polypeptide. The epitope bound by an antibody may be identified using any epitope mapping technique known in the art, including X-ray crystallography for epitope identification by direct visualization of the antigen-antibody complex, as well as monitoring the binding of the antibody to fragments or mutated variations of the antigen, or monitoring solvent accessibility of different parts of the antibody and the antigen. Exemplary strategies used to map antibody epitopes include, but are not limited to, array-based oligo-peptide scanning, limited proteolysis, site- directed mutagenesis, high-throughput mutagenesis mapping, hydrogen-deuterium exchange, and mass spectrometry (see, e.g., Gershoni et al. (2007) 21:145-56; and Hager-Braun and Tomer (2005) Expert Rev Proteomics 2:745-56).

[213] Competitive binding and epitope binning can also be used to determine antibodies sharing identical or overlapping epitopes. Competitive binding can be evaluated using a cross-blocking assay, such as the assay described in “Antibodies, A Laboratory Manual,” Cold Spring Harbor Laboratory, Harlow and Lane (1% edition 1988, 2m edition 2014). In some embodiments, competitive binding is identified when a test antibody or binding protein reduces binding of a reference antibody or binding protein to a target antigen such as HER2 (e.g., a binding protein comprising CDRs and / or variable domains selected from those identified in Tables 2-4), by at least about 50% in the cross-blocking assay (e.g., 50%, 60%, 70%, 80%, 90%, 95%, 99%, 99.5%, or more, or any percentage in between), and / or vice versa. In some embodiments, competitive binding can be due to shared or similar (e.g., partially overlapping) epitopes, or due to steric hindrance where antibodies or binding proteins bind at nearby epitopes (see, e.g., Tzartos, Methods in Molecular Biology (Morris, ed. (1998) vol. 66, pp. 55-66)). In some embodiments, competitive binding can be used to sort groups of binding proteins that share similar epitopes. For example, binding proteins that compete for binding can be “binned” as a group of binding proteins that have overlapping or nearby epitopes, while those that do not compete are placed in a separate group of binding proteins that do not have overlapping or nearby epitopes.

[214] The term "kon" or "ka" refers to the on-rate constant for association of an antibody to the antigen to form the antibody / antigen complex. The rate can be determined using standard assays, such as a surface plasmon resonance, biolayer inferometry, or ELISA assay.

[215] The term "kor" or "Kd" refers to the off-rate constant for dissociation of an antibody from the antibody / antigen complex. The rate can be determined using standard assays, such as a surface plasmon resonance, biolayer inferometry, or ELISA assay.

[216] The term "Kp" refers to the equilibrium dissociation constant of a particular antibody-antigen interaction. Ko is calculated by ka / ks. The rate can be determined using standard assays, such as a surface plasmon resonance, biolayer inferometry, or ELISA assay.

[217] The term “p” or “drug loading” or “drug:antibody ratio” or “drug-to-antibody ratio” or “DAR” refers to the number of drug moieties per antibody or antigen binding fragment, i.e., drug loading, or the number of -L-D moieties per antibody or antigen binding fragment (Ab) in ADCs of Formula (I). In ADCs comprising a splicing modulator drug moiety, “p” refers to the number of splicing modulator compounds linked to the antibody or antigen binding fragment. For example, if two splicing modulator compounds (e.g., two compounds each having the structure of D1) are linked to an antibody or antigen binding fragment, p = 2. In compositions comprising multiple copies of ADCs of Formula (1), “average p” refers to the average number of -L-D moieties per antibody or antigen binding fragment, also referred to as “average drug loading.”

[218] A “linker” or “linker moiety” is used herein to refer to any chemical moiety that is capable of covalently joining a compound, usually a drug moiety such as a splicing modulator drug moiety, to another moiety such as an antibody or antigen binding fragment. Linkers can be susceptible to or substantially resistant to acid-induced cleavage, peptidase-induced cleavage, light-based cleavage, esterase-induced cleavage, and / or disulfide bond cleavage, at conditions under which the compound or the antibody remains active.

[219] The term “agent” is used herein to refer to a chemical compound, a mixture of chemical compounds, a biological macromolecule, or an extract made from biological materials. The term “therapeutic agent” or “drug” refers to an agent that is capable of modulating a biological process and / or has biological activity. The splicing modulator compounds described herein are exemplary therapeutic agents.

[220] The term "chemotherapeutic agent” or “anti-cancer agent” is used herein to refer to all agents that are effective in treating cancer regardless of mechanism of action. Inhibition of metastasis or angiogenesis is frequently a property of a chemotherapeutic agent. Chemotherapeutic agents include antibodies, biological molecules, and small molecules, and encompass the splicing modulator compounds described herein. A chemotherapeutic agent may be a cytotoxic or cytostatic agent. The term “cytostatic agent” refers to an agent that inhibits or suppresses cell growth and / or multiplication of cells. The term "cytotoxic agent" refers to a substance that causes cell death primarily by interfering with a cell's expression activity and / or functioning.

[221] As used herein, the terms “splicing modulator,” “spliceosome modulator,” or “splice modulator” refer to compounds that have anti-cancer activity by interacting with components of the spliceosome. In some embodiments, a splicing modulator alters the rate or form of splicing in a target cell. Splicing modulators that function as inhibitory agents, for example, are capable of decreasing uncontrolled cellular proliferation. In some embodiments, the splicing modulators may act by binding to the SF3b spliceosome complex. Such modulators may be natural compounds or synthetic compounds. Non-limiting examples of splicing modulators and categories of such modulators include pladienoclide (e.g., pladienoclide D or pladienolide B), pladienoclide derivatives (e.g., pladienclide D or pladienoclide B derivatives), herboxidiene, herboxidiene derivatives, spliceostatin, spliceostatin derivatives, sudemycin, or sudemycin derivatives. As used herein, the terms “derivative” and "analog" when referring to a splicing modulator, or the like, means any such compound that retains essentially the same, similar, or enhanced biological function or activity as the original compound but has an altered chemical or biological structure. In some embodiments, the splicing modulator is a pladienolide or pladienolide derivative.

[222] As used herein, a “pladienclide derivative” refers to a compound which is structurally related to a member of the family of natural products known as the pladienolides and which retains one or more biological functions of the starting compound. Pladienolides were first identified in the bacteria Streptomyces platensis (Mizui et al. (2004) J Antibiot. 57:188-96) as being potently cytotoxic and resulting in cell cycle arrest in the G1 and G2 / M phases of the cell cycle (e.g., Bonnal et al. (2012) Nat Rev Drug Dis 11:847-59). There are seven naturally occurring pladienolides, pladienolide A-G (Mizui et al. (2004) J Antibiot. 57:188-96; Sakai et al. (2004) J Antibiotics 57:180-7). U.S. Pat. Nos. 7,884,128 and 7,816,401 describe exemplary methods of synthesizing pladienoclide B and D and are each incorporated herein by reference for such methods. Synthesis of pladienclide B and D may also be performed using the exemplary methods described in Kanada et al. ((2007) Angew Chem Int Ed. 46:4350-5). Kanada et al. and Intl. Pub. No. WO 2003 / 099813 describe exemplary methods for synthesizing E7107 (D11) (Compound 45 of WO 2003 / 099813) from Pladienolide D (11107D of WO 2003 / 099813). A corresponding U.S. Pat. No. is 7,550,503 to Kotake et al. Each of these references is incorporated herein for the described synthesis methods.

[223] As used herein, a “splicing modulator drug moiety” refers to the component of an ADC or composition that provides the structure of a splicing modulator compound, e.g., the splicing modulator (D) component in an ADC of Formula (I), or in a composition comprising -L-D.

[224] As used herein, a “spliceosome” refers to a ribonucleoprotein complex that removes introns from one or more RNA segments, such as pre-mRNA segments.

[225] The term "homolog" refers to a molecule which exhibits homology to another molecule, by for example, having sequences of chemical residues that are the same or similar at corresponding positions.

[226] The term "inhibit" or “inhibition of," as used herein, means to reduce by a measurable amount, and can include but does not require complete prevention or inhibition.

[227] The term “target-negative,” “target antigen-negative,” or “antigen-negative” refers to the absence of target antigen expression by a cell or tissue. The term “target- positive,” “target antigen-positive,” or “antigen-positive” refers to the presence of target antigen expression. For example, a cell or a cell line that does not express a target antigen may be described as target-negative, whereas a cell or cell line that expresses a target antigen may be described as target-positive.

[228] The term “bystander killing” or “bystander effect” refers to the killing of target- negative cells in the presence of target-positive cells, wherein killing of target-negative cells is not observed in the absence of target-positive cells. Cell-to-cell contact, or at least proximity between target-positive and target-negative cells, enables bystander killing. This type of killing is distinguishable from “off-target killing,” which refers to the indiscriminate killing of target-negative cells. “Off-target killing” may be observed in the absence of target-positive cells.

[229] The terms “neoplastic disorder” and “cancer” are used herein interchangeably to refer to the presence of cells possessing characteristics typical of cancer-causing cells, such as uncontrolled proliferation, immortality, metastatic potential, rapid growth and proliferation rate, and / or certain morphological features. Often, cancer cells can be in the form of a tumor or mass, but such cells may exist alone within a subject, or may circulate in the blood stream as independent cells, such as leukemic or lymphoma cells. The terms “neoplastic disorder” and "cancer" includes all types of cancers and cancer metastases, including hematological malignancy, solid tumors, sarcomas, carcinomas and other solid and non-solid tumor cancers. Hematological malignancies may include B-cell malignancies, cancers of the blood (leukemias), cancers of plasma cells (myelomas, e.g., multiple myeloma), or cancers of the lymph nodes (lymphomas). Exemplary B-cell malignancies include chronic lymphocytic leukemia (CLL), follicular lymphoma, mantle cell lymphoma, and diffuse large B-cell lymphoma. Leukemias may include acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), chronic myelomonocytic leukemia (CMML), acute monocytic leukemia (AMolL), etc. Lymphomas may include Hodgkin's lymphoma and non-Hodgkin's lymphoma. Other hematologic malignancies may include myelodysplasia syndrome (MDS). Solid tumors may include carcinomas such as adenocarcinoma, e.g., breast cancer, pancreatic cancer, prostate cancer, colon or colorectal cancer, lung cancer, gastric cancer, cervical cancer, endometrial cancer, ovarian cancer, cholangiocarcinoma, glioma, melanoma, etc

[230] The terms “tumor” and “neoplasm” refer to any mass of tissue that results from excessive cell growth or proliferation, either benign or malignant, including precancerous lesions.

[231] The terms “tumor cell’ and “neoplastic cell” are used interchangeably and refer to individual cells or the total population of cells derived from a tumor or neoplasm, including both non-tumorigenic cells and cancer stem cells. As used herein, the term “tumor cell” will be modified by the term “non-tumorigenic” when referring solely to those tumor cells lacking the capacity to renew and differentiate to distinguish those tumor cells from cancer stem cells.

[232] The terms “subject” and “patient” are used interchangeably herein to refer to any animal, such as any mammal, including but not limited to, humans, non-human primates, rodents, and the like. In some embodiments, the mammal is a mouse. In some embodiments, the mammal is a human. In some embodiments, the subject is a mouse. In some embodiments, the subject is a human.

[233] The term “co-administration” or administration “in combination with” one or more therapeutic agents includes concurrent administration and consecutive administration in any order.

[234] A “pharmaceutical composition” refers to a preparation which is in such form as to permit administration and subsequently provide the intended biological activity of the active ingredient(s) and / or to achieve a therapeutic effect, and which contains no additional components which are unacceptably toxic to a subject to which the formulation would be administered. The pharmaceutical composition may be sterile.

[235] A "pharmaceutical excipient’ comprises a material such as an adjuvant, a carrier, pH-adjusting and buffering agents, tonicity adjusting agents, wetting agents, preservative, and the like.

[236] "Pharmaceutically acceptable” means approved or approvable by a regulatory agency of the Federal or a state government, or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia, for use in animals, and more particularly in humans

[237] A "pharmaceutically acceptable salt’ is a salt that retains the desired biological activity of the parent compound and does not impart undesired toxicological effects. Examples of such salts are: (a) acid addition salts formed with inorganic acids, for example, hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, nitric acid and the like; and salts formed with organic acids, for example, acetic acid, oxalic acid, tartaric acid, succinic acid, maleic acid, fumaric acid, gluconic acid, citric acid, malic acid, ascorbic acid, benzoic acid, tannic acid, palmitic acid, alginic acid, polyglutamic acid, naphthalenesulfonic acid, methanesulfonic acid, p-toluenesulfonic acid, naphthalenedisulfonic acid, polygalacturonic acid, and the like; and (b) salts formed from elemental anions such as chlorine, bromine, and iodine. See, e.g., Haynes et al. "Commentary: Occurrence of Pharmaceutically Acceptable Anions and Cations in the Cambridge Structural Database," J Pharmaceutical Sciences, vol. 94, no. 10 (2005), and Berge et al. "Pharmaceutical Salts,” J Pharmaceutical Sciences, vol. 66, no. 1 (1977), which are incorporated by reference herein.

[238] The term “effective amount,” as used herein, refers to the amount of a compound, ADC, or composition described herein (e.g., a splicing modulator or an ADC) that is sufficient to perform a specifically stated purpose, for example to produce a therapeutic effect after administration, such as a reduction in tumor growth rate or tumor volume, a reduction in a symptom of cancer, or some other indicia of treatment efficacy. An effective amount can be determined in a routine manner in relation to the stated purpose. The term “therapeutically effective amount” refers to an amount of a compound, an ADC, or composition described herein effective for detectable killing, reduction, and / or inhibition of the growth or spread of tumor cells, the size or number of tumors, and / or other measure of the level, stage, progression and / or severity of the cancer. The therapeutically effective amount can vary depending upon the intended application (in vitro or in vivo), or the subject and disease condition being treated, e.g., the weight and age of the subject, the severity of the disease condition, the manner of administration and the like, which can readily be determined by one of ordinary skill in the art. The term also applies to a dose that will induce a particular response in target cells, e.g., inhibition of cell growth. The specific dose may vary depending on, for example, the particular pharmaceutical composition, the subject and their age and existing health conditions or risk for health conditions, the dosing regimen to be followed, the severity of the disease, whether it is administered in combination with other agents, timing of administration, the tissue to which it is administered, and the physical delivery system in which it is carried. In the case of cancer, a therapeutically effective amount of ADC can reduce the number of cancer cells, reduce tumor size, inhibit (e.g., slow or stop) tumor metastasis, inhibit (e.g., slow or stop) tumor growth, and / or relieve one or more symptoms.

[239] A "prophylactically effective amount” refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired prophylactic result. Typically, since a prophylactic dose is used in subjects prior to or at an earlier stage of disease, the prophylactically effective amount will be less than the therapeutically effective amount.

[240] As used herein, "to treat” or "therapeutic" and grammatically related terms, refer to any improvement of any consequence of disease, such as prolonged survival, less morbidity, and / or a lessening of side effects which result from an alternative therapeutic modality. As is readily appreciated in the art, full eradication of disease is encompassed but not required for a treatment act. “Treatment” or “treat,” as used herein, refers to the administration of a described ADC or composition to a subject, e.g., a patient. The treatment can be to cure, heal, alleviate, relieve, alter, remedy, ameliorate, palliate, improve or affect the disorder, the symptoms of the disorder or the predisposition toward the disorder, e.g., a cancer. In some embodiments, in addition to treating a subject with a condition, a composition disclosed herein can also be provided prophylactically to prevent or reduce the likelihood of developing that condition.

[241] In some embodiments, a labeled ADC is used. Suitable "labels" include radionuclides, enzymes, substrates, cofactors, inhibitors, fluorescent moieties, chemiluminescent moieties, magnetic particles, and the like.

[242] By "protein," as used herein, is meant at least two covalently attached amino acids. The term encompasses polypeptides, oligopeptides, and peptides. In some embodiments, the two or more covalently attached amino acids are attached by a peptide bond. The protein may be made up of naturally occurring amino acids and peptide bonds, for example when the protein is made recombinantly using expression systems and host cells. Alternatively, the protein may include synthetic amino acids (e.g., homophenylalanine, citrulline, ornithine, and norleucine), or peptidomimetic structures, i.e., "peptide or protein analogs,” such as peptoids. Peptoids are an exemplary class of peptidomimetics whose side chains are appended to the nitrogen atom of the peptide backbone, rather than to the a-carbons (as they are in amino acids), and have different hydrogen bonding and conformational characteristics in comparison to peptides (see, e.g., Simon et al. (1992) Proc Natl Acad Sci. USA 89:9367). As such, peptoids can be resistant to proteolysis or other physiological or storage conditions, and effective at permeating cell membranes. Such synthetic amino acids may be incorporated in particular when the antibody is synthesized in vitro by conventional methods well known in the art. In addition, any combination of peptidomimetic, synthetic and naturally occurring residues / structures can be used. "Amino acid" also includes imino acid residues, such as proline and hydroxyproline. The amino acid "R group" or "side chain” may be in either the (L)- or the (S)-configuration. In a specific embodiment, the amino acids are in the (L)- or (S)-configuration.

[243] A "recombinant protein" is a protein made using recombinant techniques using any techniques and methods known in the art, i.e., through the expression of a recombinant nucleic acid. Methods and techniques for the production of recombinant proteins are well known in the art.

[244] An "isolated" protein is unaccompanied by at least some of the material with which it is normally associated in its natural state, for example constituting at least about 5%, or at least about 50% by weight of the total protein in a given sample. tis understood that the isolated protein may constitute from 5% to 99.9% by weight of the total protein content depending on the circumstances. For example, the protein may be made at a significantly higher concentration through the use of an inducible promoter or high expression promoter, such that the protein is made at increased concentration levels. The definition includes the production of an antibody in a wide variety of organisms and / or host cells that are known in the art.

[245] For amino acid sequences, sequence identity and / or similarity may be determined using standard techniques known in the art, including, but not limited to, the local sequence identity algorithm of Smith and Waterman (1981) Adv Appl Math. 2:482, the sequence identity alignment algorithm of Needleman and Wunsch (1970) J Mol Biol. 48:443, the search for similarity method of Pearson and Lipman (1988) Proc Nat Acad Sci. USA 85:2444, computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group, 575 Science Drive, Madison, Wis.), the Best Fit sequence program described by Devereux et al. (1984) Nucl Acid Res. 12:387-95, preferably using the default settings, or by inspection. Preferably, percent identity is calculated by FastDB based upon the following parameters: mismatch penalty of 1; gap penalty of 1; gap size penalty of 0.33; and joining penalty of 30 ("Current Methods in Sequence Comparison and Analysis," Macromolecule Sequencing and Synthesis, Selected Methods and Applications, pp. 127-149 (1988), Alan R. Liss, Inc).

[246] An example of a useful algorithm is PILEUP. PILEUP creates a multiple sequence alignment from a group of related sequences using progressive, pairwise alignments. It can also plot a tree showing the clustering relationships used to create the alignment. PILEUP uses a simplification of the progressive alignment method of Feng & Doolittle (1987) J Mol Evol. 35:351-60; the method is similar to that described by Higgins and Sharp (1989) CABIOS 5:151-3. Useful PILEUP parameters including a default gap weight of 3.00, a default gap length weight of 0.10, and weighted end gaps.

[247] Another example of a useful algorithm is the BLAST algorithm, described in: Altschul et al. (1990) J Mol Biol. 215:403-10; Altschul et al. (1997) Nucl Acid Res. 25:3389-402; and Karin et al. (1993) Proc Natl Acad Sci. USA 90:5873-87. A particularly useful BLAST program is the WU-BLAST-2 program which was obtained from Altschul et al. (1996) Methods in Enzymology 266:460-80. WU-BLAST-2 uses several search parameters, most of which are set to the default values. The adjustable parameters are set with the following values: overlap span=|, overlap fraction=0.125, word threshold (T)=Il. The HSP S and HSP S2 parameters are dynamic values and are established by the program itself depending upon the composition of the particular sequence and composition of the particular database against which the sequence of interest is being searched; however, the values may be adjusted to increase sensitivity.

[248] An additional useful algorithm is gapped BLAST as reported by Altschul et al. (1997) Nucl Acid Res. 25:3389-402. Gapped BLAST uses BLOSUM-62 substitution scores; threshold T parameter set to 9; the two-hit method to trigger ungapped extensions, charges gap lengths of k a cost of 10+k; Xu set to 16, and Xg set to 40 for database search stage and to 67 for the output stage of the algorithms. Gapped alignments are triggered by a score corresponding to about 22 bits.

[249] Generally, the amino acid homology, similarity, or identity between proteins disclosed herein and variants thereof, including variants of target antigens (such as HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A6, SLC44A4, or STEAP1) and variants of antibody variable domains (including individual variant CDRs), are at least 80% to the sequences depicted herein, e.g., homologies or identities of at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, almost 100%, or 100%.

[250] In a similar manner, "percent (%) nucleic acid sequence identity” with respect to the nucleic acid sequence of the antibodies and other proteins identified herein is defined as the percentage of nucleotide residues in a candidate sequence that are identical with the nucleotide residues in the coding sequence of the antigen binding protein. A specific method utilizes the BLASTN module of WU-BLAST-2 set to the default parameters, with overlap span and overlap fraction set to 1 and 0.125, respectively.

[251] While the site or region for introducing an amino acid sequence variation is predetermined, the mutation per se need not be predetermined. For example, in order to optimize the performance of a mutation at a given site, random mutagenesis may be conducted at the target codon or region and the expressed antigen binding protein CDR variants screened for the optimal combination of desired activity. Techniques for making substitution mutations at predetermined sites in DNA having a known sequence are well known, for example, MI3 primer mutagenesis and PCR mutagenesis

[252] "Alkyl" or "alkyl group,” as used herein, means a straight-chain, branched, or cyclic hydrocarbon chain that is completely saturated. In certain embodiments, alkyl groups may contain 1-8 carbon atoms (“Cs-Csalkyl"). In certain embodiments, alkyl groups may contain 1-6 carbon atoms ("C4-Csalkyl"). In certain embodiments, alkyl groups contain 1-3 carbon atoms. In still other embodiments, alkyl groups contain 2-3 carbon atoms, and in yet other embodiments alkyl groups contain 1-2 carbon atoms.

[253] “Alkylalkoxy," as used herein, means an alkyl group substituted with an alkoxy group. "Alkoxy", as used herein, refers to an alkyl group, as previously defined, attached to the principal carbon chain through an oxygen ("alkoxy") atom.

[254] "Alkylamino," as used herein, means an alkyl group substituted with an amino group. "Amino," as used herein, refers to -NHz, -NH(alkyl), or -N(alkyl)(alkyl).

[255] "Alkylhydroxy,” as used herein, means an alkyl group substituted with an amino group. "Hydroxy" or "hydroxyl," as used herein, refers to =OH.

[256] "Alkylene" refers to a divalent radical of an alkyl group. For example, -CHa-, - CH2CHz-, -CH2CH2CHz-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, and - CH2CH2CH2CH2CH2CH.- refer to methylene, ethylene, n-propylene, n-butylene, n- pentylene, and n-hexylene, respectively.

[257] "Carbocycle," as used herein, includes both aromatic (e.g., aryl) and non- aromatic (e.g., cycloalkyl) groups. In certain embodiments, carbocycle groups contain 3-10 carbon atoms (“3 to 10 membered carbocycle”). In certain embodiments, carbocycle groups contain 3-8 carbon atoms (“3 to 8 membered carbocycle”). In certain embodiments, carbocycle groups contain 3-6 carbon atoms (“3 to 6 membered carbocycle”). In certain embodiments, carbocycle groups contain 3-5 carbon atoms (“3 to 5 membered carbocycle”).

[258] "Halogen" refers to a radical of any halogen, e.g., -F, -Cl, -Br, or -I.

[259] The terms "heterocycle", "heterocyclyl", and "heterocyclic" as used herein, mean a monocyclic heterocycle, a bicyclic heterocycle, or a tricyclic heterocycle containing at least one heteroatom in the ring.

[260] The monocyclic heterocycle is a 3-, 4-, 5-, 6-, 7, or 8-membered ring containing at least one heteroatom independently chosen from O, N, and S. In some embodiments, the heterocycle is a 3- or 4-membered ring containing one heteroatom chosen from O, N and S. In some embodiments, the heterocycle is a 5-membered ring containing zero or one double bond and one, two or three heteroatoms chosen from O, N and S. In some embodiments, the heterocycle is a 6-, 7-, or 8-membered ring containing zero, one or two double bonds and one, two or three heteroatoms chosen from O, N and S. Representative examples of monocyclic heterocycle include, but are not limited to, azetidinyl, azepanyl, aziridinyl, diazepanyl, 1 ,3-dioxanyl, 1,3-dioxolanyl, dihydropyranyl (including 3,4-dihydro-2H-pyran-6-yl), 1,3-dithiolanyl, 1,3-dithianyl, imidazolinyl, imidazolidinyl, isothiazolinyl, isothiazolidinyl, isoxazolinyl, isoxazolidinyl, morpholinyl, oxadiazolinyl, oxadiazolidinyl, oxazolinyl, oxazolidinyl, piperazinyl, piperidinyl, pyranyl, pyrazolinyl, pyrazolidinyl, pyrrolinyl, pyrrolidinyl, tetrahydrofuranyl, tetrahydropyranyl (including tetrahydro-2H-pyran-4-yl), tetrahydrothienyl, thiadiazolinyl, thiadiazolidinyl, thiazolinyl, thiazolidinyl, thiomorpholinyl, 1,1-dioxidothiomorpholinyl (thiomorpholine sulfone), thiopyranyl, and trithianyl.

[261] The bicyclic heterocycles of the present disclosure may include a monocyclic heterocycle fused to an aryl group, or a monocyclic heterocycle fused to a monocyclic cycloalkyl, or a monocyclic heterocycle fused to a monocyclic cycloalkenyl, or a monocyclic heterocycle fused to a monocyclic heterocycle having a total of 5 to 12 ring atoms. Examples of bicyclic heterocycles include, but are not limited to, 3,4-dihydro-2H- pyranyl, 1,3-benzodioxolyl, 1,3-benzodithiolyl, 2,3-dihydro-1,4-benzodioxinyl, 2,3- dihydro-1-benzofuranyl, 2,3-dihydro-1-benzothienyl, 2,3-dihydro-1H-indolyl, and 1,2,3,4- tetrahydroquinolinyl.

[262] The terms "heterocycle", "heterocyclyl", and "heterocyclic" encompass heteroaryls. "Heteroaryl" refers to a cyclic moiety having one or more closed rings, with one or more heteroatoms (oxygen, nitrogen or sulfur) in at least one of the rings, wherein at least one of the rings is aromatic, and wherein the ring or rings may independently be fused, and / or bridged. Examples include without limitation phenyl, thiophenyl, triazolyl, pyridinyl, pyrimidinyl, pyridazinyl, and pyrazinyl.

[263] As described herein, compounds of the disclosure may contain “optionally substituted” moieties. In general, the term “substituted,” whether preceded by the term “optionally” or not, means that one or more hydrogens of the designated moiety are replaced with a suitable substituent. Unless otherwise indicated, an “optionally substituted” group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent chosen from a specified group, the substituent may be either the same or different at each position. Combinations of substituents envisioned under this disclosure are preferably those that result in the formation of stable or chemically feasible compounds.

[264] One skilled in the art will be understand that “substitution” or “substituted with” or “absent” includes the implicit proviso that such substitution or absence is in accordance with permitted valence of the substituted atom and the substituent, and that the substitution or absence results in a stable compound, e.g., which does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc. For purposes of this disclosure, the heteroatoms such as nitrogen may have hydrogen substituents, and / or any permissible substituents of organic compounds described herein which satisfy the valences of the heteroatoms.

[265] "Stable" refers to compounds that are not substantially altered chemically and / or physically when subjected to conditions to allow for their production, detection, and, in certain embodiments, their recovery, purification, and use for one or more of the purposes disclosed herein. In some embodiments, a stable compound or chemically feasible compound is one that is not substantially altered when kept at a temperature of 40 °C or less, in the absence of moisture or other chemically reactive conditions, for at least a week. In some embodiments, the compounds disclosed herein are stable.

[266] Enantiomers taught herein may include “enantiomerically pure" isomers that comprise substantially a single enantiomer, for example, greater than or equal to 90%, 92%, 95%, 98%, or 99%, or equal to 100% of a single enantiomer, at a particular asymmetric center or centers. An "asymmetric center” or "chiral center" refers to a tetrahedral carbon atom that comprises four different substituents.

[267] The compounds described herein may also contain unnatural proportions of atomic isotopes at one or more of the atoms that constitute such compounds. For example, the compounds may be radiolabeled with radioactive isotopes, such as, for example, deuterium (2H), tritium (*H), carbon-13 ('*C), or carbon-14 (4C). All isotopic variations of the compounds disclosed herein, whether radioactive or not, are intended to be encompassed within the scope of the present disclosure. In addition, all tautomeric forms of the compounds described herein are intended to be within the scope of the claimed disclosure. Antibody-Drug Conjugates

[268] The antibody-drug conjugate (ADC) compounds of the present disclosure include those with anti-cancer activity. In particular, the ADC compounds include an antibody or antigen binding fragment (including an antigen binding fragment thereof) conjugated (i.e., covalently attached by a linker) to a drug moiety (e.g., a splicing modulator), wherein the drug moiety when not conjugated to an antibody or antigen binding fragment has a cytotoxic or cytostatic effect. In various embodiments, the drug moiety when not conjugated to an antibody or antigen binding fragment is capable of binding to and / or interacting with the SF3b spliceosome complex. In various embodiments, the drug moiety when not conjugated to an antibody or antigen binding fragment is capable of modulating in vitro and / or in vivo RNA splicing. By targeting RNA splicing, in various embodiments, the drug moieties and ADCs disclosed herein are potent antiproliferative agents. In various embodiments, the drug moieties and ADCs disclosed herein can target both actively dividing and quiescent cells.

[269] In various embodiments, the present disclosure is based, at least in part, on the discovery that certain biologically active splicing modulators may provide improved properties when used in ADCs. While a splicing modulator may show desirably improved features (e.g., robust SF3b spliceosome complex binding, potent modulation of RNA splicing) when used on its own, in various embodiments, the splicing modulator may exhibit fewer of the same desirably improved features when conjugated to an antibody or antigen binding fragment. Thus, the development and production of an ADC for use as a human therapeutic agent, e.g., as an oncologic agent, may require more than the identification of an antibody capable of binding to a desired target or targets and attaching to a drug used on its own to treat cancer. Linking the antibody to the drug may have significant effects on the activity of one or both of the antibody and the drug, effects which will vary depending on the type of linker and / or drug chosen. In some embodiments, therefore, the components of the ADC are selected to (i) retain one or more therapeutic properties exhibited by the antibody and drug moieties in isolation, (ii) maintain the specific binding properties of the antibody or antigen binding fragment; (iii) optimize drug loading and drug-to-antibody ratios; (iv) allow delivery, e.g., intracellular delivery, of the drug moiety via stable attachment to the antibody or antigen binding fragment; (v) retain ADC stability as an intact conjugate until transport or delivery to a target site; (vi) minimize aggregation of the ADC prior to or after administration; (vii) allow for the therapeutic effect, e.g., cytotoxic effect, of the drug moiety after cleavage or other release mechanism in the cellular environment; (viii) exhibit in vivo anti-cancer treatment efficacy comparable to or superior to that of the antibody and drug moieties in isolation; (ix) minimize off-target killing by the drug moiety; and / or (x) exhibit desirable pharmacokinetic and pharmacodynamics properties, formulatability, and toxicologic / immunologic profiles. Each of these properties may be needed to identify an improved ADC for therapeutic use (Ab et al. (2015) Mol Cancer Ther. 14:1605-13).

[270] In various embodiments, the ADCs disclosed herein exhibit unexpectedly favorable properties in some or each of the categories listed above. For instance, in some embodiments, the ADC constructs disclosed herein exhibit surprisingly favorable drug loading, aggregation, and / or stability profiles, and / or preserve antibody binding function, drug activity, and / or improved bystander killing, while reducing off-target killing, as compared to ADCs comprising an alternate linker and / or drug moiety (e.g., an alternate splicing modulator). In some embodiments, ADC constructs disclosed herein demonstrate superior stability, activity, potency, or other effect (measured in vivo or in vitro) as compared to ADCs using an alternate linker and / or drug moiety (e.g., an alternate splicing modulator). In some embodiments, the ADC constructs disclosed herein exhibit in vivo treatment efficacy when administered as a single dose. In some embodiments, the ADC constructs disclosed herein are surprisingly stable as compared to ADCs using an alternate linker and / or drug moiety (e.g., an alternate splicing modulator).

[271] The ADC compounds of the present disclosure may selectively deliver an effective dose of a cytotoxic or cytostatic agent to cancer cells or to tumor tissue. It has been discovered that the disclosed ADCs have potent cytotoxic and / or cytostatic activity against cells expressing the respective target antigen (e.g., HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A8, SLC44A4, STEAP1). In some embodiments, the cytotoxic and / or cytostatic activity of the ADC is dependent on target antigen expression in a cell. In some embodiments, the disclosed ADCs are particularly effective at killing cancer cells expressing a target antigen while minimizing off-target killing. In some embodiments, the disclosed ADCs do not exhibit a cytotoxic and / or cytostatic effect on cancer cells that do not express a target antigen.

[272] Exemplary HER2-expressing cancers include but are not limited to breast cancer, gastric cancer, bladder cancer, urothelial cell carcinoma, esophageal cancer, lung cancer (e.g., lung adenocarcinoma), uterine cancer (e.g., uterine serous endometrial carcinoma), salivary duct carcinoma, cervical cancer, endometrial cancer, and ovarian cancer (English et al. (2013) Mol Diagn Ther. 17:85-99).

[273] Exemplary CD138-expressing cancers include but are not limited to intrathoracic cancer (e.g., lung cancer, mesothelioma), skin cancer (e.g., basal cell carcinoma, squamous cell carcinoma), head and neck cancer (e.g., laryngeal, hypopharynx, nasopharyngeal), breast cancer, urogenital cancer (e.g., cervical cancer, ovarian cancer, endometrial cancer, prostate cancer, bladder cancer, urothelial cancer), hematological malignancies (e.g., myeloma such as multiple myeloma, B-cell malignancies, Hodgkin's lymphoma), and thyroid cancer (Szatmari et al. (2015) Dis Markers 2015:796052).

[274] Exemplary EPHA2-expressing cancers include breast cancer, brain cancer, ovarian cancer, bladder cancer, pancreatic cancer, esophageal cancer, lung cancer, prostate cancer, melanoma, esophageal cancer, and gastric cancer (Tandon et al. (2011) Expert Opin Ther Targets 15(1):31-51).

[275] In some embodiments, cleavage of an ADC releases the splicing modulator from the antibody or antigen binding fragment and linker. In some embodiments, the linker and / or splicing modulator is designed to facilitate bystander killing (the killing of neighboring cells). In some embodiments, the linker and / or splicing modulator is designed to facilitate bystander killing through cleavage after cellular internalization and diffusion of the linker-drug moiety and / or the drug moiety alone to neighboring cells. In some embodiments, the linker promotes cellular internalization. In some embodiments, the linker is designed to minimize cleavage in the extracellular environment and thereby reduce toxicity to off-target tissue (e.g., non-cancerous tissue), while preserving ADC binding to target tissue and bystander killing of cancerous tissue that does not express an antigen targeted by the antibody or antigen binding fragment of an ADC, but surrounds target cancer tissue expressing that antigen. In some embodiments, the drug moiety, or the catabolite of the drug moiety produced by cleavage of an ADC, is designed to facilitate uptake by target cells or by neighboring cells (i.e., cell permeable). Such drug moieties and catabolites may be referred to herein as “bystander active,” whereas drug moieties or catabolites with reduced cell permeability may be referred to as “bystander inactive.”

[276] In some embodiments, the disclosed ADCs also demonstrate bystander killing activity, but low off-target cytotoxicity. Without being bound by theory, the bystander killing activity of an ADC may be particularly beneficial where its penetration into a solid tumor is limited and / or target antigen expression among tumor cells is heterogeneous. In some embodiments, an ADC comprising a cleavable linker is particularly effective at bystander killing and / or demonstrates improved bystander killing activity, relative to comparable treatment with an ADC comprising a non-cleavable linker. In some embodiments, the ADCs disclosed herein exhibit improved solubility and target cell penetrance over the drug moieties on their own. In some embodiments, the ADCs disclosed herein exhibit improved cytotoxicity over that of the drug moiety on its own. In some embodiments, ADCs disclosed herein use drug moieties that exhibit lower cytotoxicity, when evaluated as a stand-alone drug, yet are surprisingly better than ADCs comprising other drug moieties which have higher cytotoxicity when evaluated as a stand-alone drug. In some embodiments, cleavage and release of the splicing modulator improves cytotoxicity of the ADC, relative to comparable treatment with an ADC comprising a non-cleavable linker. In other embodiments, cleavage and release of the splicing modulator is not required for an ADC to possess a desirable biological activity. In some embodiments, an ADC comprising a non-cleavable linker having increased spacer length (e.g., ADL12) provides the same or similar cytotoxicity relative to comparable treatment with an ADC comprising a cleavable linker (e.g., ADL1, ADL5) and surprisingly superior cytotoxicity relative to comparable treatment with an ADC comprising a shorter non-cleavable linker. In some embodiments, an ADC comprising a non-cleavable linker having increased spacer length without a carbonyl group (e.g., ADL12) provides the same or similar cytotoxicity relative to comparable treatment with an ADC comprising a cleavable linker (e.g., ADL1, ADL5) and surprisingly superior cytotoxicity relative to comparable treatment with an ADC comprising a non-cleavable linker having the same or similar spacer length with a carbonyl group (e.g., ADL10). In some embodiments, the removal of a carbonyl group from a non-cleavable MC linker (e.g., ADL12) can result in a greater than 50-fold, greater than 75-fold, greater than 100- fold, greater than 150-fold, or greater than 200-fold increase in cytotoxicity, relative to comparable treatment with an ADC comprising an unmodified non-cleavable MC linker (e.g., ADL10). In some embodiments, the removal of a carbonyl group from a non- cleavable MC linker (e.g., ADL12) and increased spacer length (e.g., the addition of at least one spacer unit) can result in a greater than 50-fold, greater than 75-fold, greater than 100-fold, greater than 150-fold, or greater than 200-fold increase in cytotoxicity, relative to comparable treatment with an ADC comprising an unmodified non-cleavable MC linker (e.g., ADL10).

[277] Provided herein are ADC compounds comprising an antibody or antigen binding fragment thereof (Ab) which targets a tumor cell, a splicing modulator drug moiety (D), and a linker moiety (L) that covalently attaches Ab to D. In certain aspects, the antibody or antigen binding fragment is able to bind to a tumor-associated antigen (e.g., HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A6, SLC44A4, STEAP1) with high specificity and high affinity. In certain embodiments, the antibody or antigen binding fragment is internalized into a target cell upon binding, e.g., into a degradative compartment in the cell. In various embodiments, ADCs that internalize upon binding to a target cell, undergo degradation, and release the splicing modulator drug moiety to kill cancer cells may be used. The splicing modulator drug moiety may be released from the antibody and / or the linker moiety of the ADC by enzymatic action, hydrolysis, oxidation, or any other mechanism

[278] An exemplary ADC has Formula (1): Ab-(L-D), [0} wherein Ab = an antibody or antigen binding fragment, L = a linker moiety, D = a splicing modulator drug moiety, and p = the number of splicing modulator drug moieties per antibody or antigen binding fragment.

[279] In certain preferred embodiments, the drug-targeting moiety for use in the described ADCs and compositions is an antibody or antigen binding fragment. Other exemplary drug-targeting moieties for use in the described ADCs and compositions are also provided and described herein. In some embodiments, a drug-targeting moiety can be any one of a variety of cell-binding agents and non-antibody scaffolds. In some embodiments, the drug-targeting moiety is a cell-binding agent. As used herein, the term “cell-binding agent” refers to any agent that is capable of binding to an animal (e.g., human) cell and delivering a drug moiety (e.g., a splicing modulator drug moiety as disclosed herein). The term encompasses the exemplary antibodies and antigen binding fragments disclosed herein (e.g., monoclonal antibodies and fragments thereof such as Fabs and scFVs). The term further encompasses exemplary cell-binding agents such as DARPIns, duobodies, bicyclic peptides, nanobodies, centyrins, MSH (melanocyte-stimulating hormone), receptor-Fc fusion molecules, T-cell receptor structures, steroid hormones such as androgens and estrogens, growth factors, colony- stimulating factors such as EGF, and other non-antibody scaffolds. In various embodiments, non-antibody scaffolds can broadly fall into two structural classes, namely domain-sized compounds (approximately 6-20 kDa) and constrained peptides (approximately 2-4 kDa). Exemplary domain-sized scaffolds include but are not limited to affibodies, affilins, anticalins, atrimers, DARPins, FN3 scaffolds (e.g., adnectins and centyrins), fynomers, Kunitz domains, pronectins, O-bodies, and receptor-Fc fusion proteins, whereas exemplary constrained peptides include avimers, bicyclic peptides, and Cys-knots. In some embodiments, the drug-targeting moiety used in the described ADCs and compositions is selected from an affibody, an affilin, an anticalin, an atrimer, a DARPIn, a FN3 scaffold such as an adnectin or a centyrin, a fynomer, a Kunitz domain, a pronectin, an O-body, an avimer, a bicyclic peptide, and a Cys-knot. In some embodiments, the drug-targeting moiety used in the described ADCs and compositions is a receptor-Fc fusion protein, e.g., a HER2-Fc chimeric fusion protein. Non-antibody scaffolds are reviewed, e.g., in Vazquez-Lombardi et al. (2015) Drug Dis Today 20(10):1271-83. Antibodies

[280] The antibody or antigen binding fragment (Ab) of Formula (1) includes within its scope any antibody or antigen binding fragment that specifically binds to a target antigen on a cancer cell. The antibody or antigen binding fragment may bind to a target antigen with a dissociation constant (Ko) of <1 mM, <100 nM or £10 nM, or any amount in between, as measured by, e.g., BlAcore® analysis. In certain embodiments, the Kp is 1 pM to 500 pM. In some embodiments, the Ko is between 500 pM to 1 uM, 1 uM to 100 nM, or 100 mM to 10 nM.

[281] In some embodiments, the antibody or antigen binding fragment is a four-chain antibody (also referred to as an immunoglobulin or a full-length or intact antibody), comprising two heavy chains and two light chains. In some embodiments, the antibody or antigen binding fragment is a two-chain half body (one light chain and one heavy chain), or an antigen binding fragment of an immunoglobulin. In some embodiments, the antibody or antigen binding fragment is an antigen binding fragment of an immunoglobulin that retains the ability to bind a target cancer antigen and / or provide a function of an immunoglobulin.

[282] In some embodiments, the antibody or antigen binding fragment is an antibody or antigen binding fragment thereof. In some embodiments, the antibody or antigen binding fragment is an internalizing antibody or internalizing antigen binding fragment thereof. In some embodiments, the internalizing antibody or internalizing antigen binding fragment thereof binds to a target cancer antigen expressed on the surface of a cell and enters the cell upon binding. In some embodiments, the splicing modulator drug moiety of the ADC is released from the antibody or antigen binding fragment of the ADC after the ADC enters and is present in a cell expressing the target cancer antigen (i.e., after the ADC has been internalized), e.g., by cleavage, by degradation of the antibody or antigen binding fragment, or by any other suitable release mechanism.

[283] Amino acid sequences of exemplary antibodies of the present disclosure are set forth in Tables 2-4. Table 1. Antibodies Table 2. Amino acid sequences of mAb variable regions Table 5. Exemplary target antigen amino acid sequences Antigen SEQID NO | Amino acid sequence HER2 / NEU | 31 MELAALCRWGLLLALLPPGAASTQVCTGT DMKLRLPASPETHLDM LRHLYQGCQVVQGNLELTYLPTNASLSFLQDIQEVQGYVLIAHNQ VRQVPLQRLRIVRGTQLFEDNYALAVLDNGDPLNNTTPVTGASPG GLRELQLRSLTEILKGGVLIQRNPQLCYQDT ILWKDIFHKNNQLA LTLIDTNRSRACHPCSPMCKGSRCWGESSEDCQSLTRTVCAGGCA RCKGPLPTDCCHEQCAAGCTGPKHSDCLACLHFNHSGICELHCPA LVTYNTDTFESMPNPEGRYTFGASCVTACPYNYLSTDVGSCTLVC PLHNQEVTAEDGTQRCEKCSKPCARVCYGLGMEHLREVRAVTSAN IQEFAGCKKIFGSLAFLPESFDGDPASNTAPLQPEQLQVFETLEE ITGYLYISAWPDSLPDLSVFQNLQVIRGRILENGAYSLTLQGLGI SWLGLRSLRELGSGLALIHHNTHLCFVHT VPWDQLFRNPEQALLE TANRPEDECVGEGLACHQLCARGHCWGPGPTQCVNCSQFLRGQEC VEECRVLQGLPREYVNARHCLPCHPECQPQNGSVTCFGPEADQCY ACAHYKDPPFCVARCPSGVKPDLSYMPIWKEFPDEEGACQPCPINC THSCVDLDDKGCPAEQRASPLTSIISAVVGILLVVVLGVVFGILI KRRQQKIRKYTMRRLLQETELVEPLTPSGAMPNQAQMRILKETEL RKVKVLGSGAFGTVYKGIWIPDGENVKIPVAIKVLRENTSPKANK EILDEAYVMAGVGSPYVSRLLGICLTSTVQLVTQLMPYGCLLDHV RENRGRLGSQDLLNWCMQIAKGMSYLEDVRLVHRDLARRNVLVKS PNHVKITDFGLARLLDIDETEYHADGGKVPIKWMALESILRRRET HQSDVWSYGVTVWELMT FGAKPY DGIPAREI PDLLEKGERLPQPP ICTIDVYMIMVKCWMIDSECRPRFRELVSEFSRMARDPQRFVVIQ NEDLGPASPLDST FYRSLLEDDDMGDLVDAEEYLVPQQGFFCPDP APGAGGMVHHRHRSSSTRSGGGDLTLGLEPSEEEAPRSPLAPSEG AGSDVFDGDLGMGAAKGLQSLPTHEDPSPLQRY SEDPTVPLPSETD GYVAPLTCSPQPEYVNQPDVRPQPPSPREGPLPAARPAGATLERP KTLSPGKNGVVKDVFAFGGAVENPEYLTPQGGAAPQPHPPPAFSP AFDNLYYWDQDPPERGAPPSTFKGT PTAENPEYLGLDVEY

[284] In various embodiments, an ADC disclosed herein may comprise any set of heavy and light chain variable domains listed in the tables above, or the set of six CDR sequences from the heavy and light chain set, e.g., by transplanting the six CDRs into a chosen human donor antibody framework. In various embodiments, an ADC disclosed herein may comprise amino acid sequences that are homologous to the sequences listed in the tables above, so long as the ADC retains the ability to bind to its target cancer antigen (e.g., with a Kp of less than 1x10 M) and retains one or more functional properties of the ADCs disclosed herein (e.g., ability to internalize, modulate RNA splicing, inhibit cell growth, etc.).

[285] In some embodiments, the ADC further comprises human heavy and light chain constant domains or fragments thereof. For instance, the ADC may comprise a human 19G heavy chain constant domain (such as an IgG1) and a human kappa or lambda light chain constant domain. In various embodiments, the antibody or antigen binding fragment of the described ADCs comprises a human immunoglobulin G subtype 1 (IgG1) heavy chain constant domain with a human Ig kappa light chain constant domain.

[286] In various other embodiments, the target cancer antigen for an ADC is human epidermal growth factor receptor 2 (HER2).

[287] In various embodiments, the anti-HER2 antibody or antigen binding fragment thereof comprises three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) consisting of SEQ ID NO:1, heavy chain CDR2 (HCDR2) consisting of SEQ ID NO:2, heavy chain CDR3 (HCDR3) consisting of SEQ ID NO:3; light chain CDR1 (LCDR1) consisting of SEQ ID NO:4, light chain CDR2 (LCDR2) consisting of SEQ ID NO:5, and light chain CDR3 (LCDRS3) consisting of SEQ ID NO:6, as defined by the Kabat numbering system.

[288] In various embodiments, the anti-HER2 antibody or antigen binding fragment thereof comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising the amino acid sequence of SEQ ID NO:20. In some embodiments, the anti-HER2 antibody or antigen binding fragment thereof comprises the heavy chain variable region amino acid sequence of SEQ ID NO:19 and the light chain variable region amino acid sequence of SEQ ID NO:20, or sequences that are at least 95% identical to the disclosed sequences. In some embodiments, the anti-HER2 antibody or antigen binding fragment thereof has a heavy chain variable region amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:19 and / or a light chain variable region amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO: 20.

[289] In various embodiments, the anti-HER2 antibody or antigen binding fragment thereof is an internalizing antibody or internalizing antigen binding fragment. In various embodiments, the anti-HER2 antibody comprises a human IgG1 heavy chain constant domain and a human Ig kappa light chain constant domain.

[290] In various embodiments, the anti-HER2 antibody comprises the heavy chain amino acid sequence of SEQ ID NO:19 or a sequence that is at least 95% identical to SEQ ID NO:19, and the light chain amino acid sequence of SEQ ID NO:20 or a sequence that is at least 95% identical to SEQ ID NO:20. In particular embodiments, the anti-HER2 antibody comprises the heavy chain amino acid sequence of SEQ ID NO:19 and the light chain amino acid sequence of SEQ ID NO:20, or sequences that are at least 95% identical to the disclosed sequences. In some embodiments, the anti- HER2 antibody has a heavy chain amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:19 and a light chain amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:20. In various embodiments, the anti-HER2 antibody is trastuzumab, or an antigen binding fragment thereof.

[291] In various embodiments, the anti-HER2 antibody or antigen binding fragment thereof comprises the three heavy chain CDRs and three light chain CDRs of trastuzumab or wherein the CDRs include no more than one, two, three, four, five, or six amino acid additions, deletions or substitutions of HCDR1 (SEQ ID NO:1), HCDR2 (SEQ ID NO:2), HCDR3 (SEQ ID NO:3); LCDR1 (SEQ ID NO:4), LCDR2 (SEQ ID NO:5), and LCDR3 (SEQ ID NO:6).

[292] In various other embodiments, the target cancer antigen for an ADC is human syndecan-1 (CD138).

[293] In various embodiments, the anti-CD138 antibody or antigen binding fragment thereof comprises three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) consisting of SEQ ID NO:7, heavy chain CDR2 (HCDR2) consisting of SEQ ID NO:8, heavy chain CDR3 (HCDRS3) consisting of SEQ ID NO:9; light chain CDR1 (LCDR) consisting of SEQ ID NO:10, light chain CDR2 (LCDR2) consisting of SEQ ID NO:11, and light chain CDR3 (LCDR3) consisting of SEQ ID NO:12, as defined by the Kabat numbering system.

[294] In various embodiments, the anti-CD138 antibody or antigen binding fragment thereof comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising the amino acid sequence of SEQ ID NO:22. In some embodiments, the anti-CD138 antibody or antigen binding fragment thereof comprises the heavy chain variable region amino acid sequence of SEQ ID NO:21 and the light chain variable region amino acid sequence of SEQ ID NO:22, or sequences that are at least 95% identical to the disclosed sequences. In some embodiments, the anti-CD138 antibody or antigen binding fragment thereof has a heavy chain variable region amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:21 and / or a light chain variable region amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:22.

[295] In various embodiments, the anti-CD138 antibody or antigen binding fragment thereof is an internalizing antibody or internalizing antigen binding fragment. In various embodiments, the anti-CD138 antibody comprises a murine IgG2a heavy chain constant domain and a murine Ig kappa light chain constant domain. In various embodiments, the anti-CD138 antibody comprises a human 1gG2a heavy chain constant domain and a human Ig kappa light chain constant domain.

[296] In various embodiments, the anti-CD138 antibody comprises the heavy chain amino acid sequence of SEQ ID NO:21 or a sequence that is at least 95% identical to SEQ ID NO:21, and the light chain amino acid sequence of SEQ ID NO:22 or a sequence that is at least 95% identical to SEQ ID NO:22. In particular embodiments, the anti-CD138 antibody comprises the heavy chain amino acid sequence of SEQ ID NO:21 and the light chain amino acid sequence of SEQ ID NO:22, or sequences that are at least 95% identical to the disclosed sequences. In some embodiments, the anti- CD138 antibody has a heavy chain amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:21 and a light chain amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:22. In various embodiments, the anti-CD138 antibody is B-B4, or an antigen binding fragment thereof.

[297] In various embodiments, the anti-CD138 antibody or antigen binding fragment thereof comprises the three heavy chain CDRs and three light chain CDRs of B-B4 or wherein the CDRs include no more than one, two, three, four, five, or six amino acid additions, deletions or substitutions of HCDR1 (SEQ ID NO:7), HCDR2 (SEQ ID NO:8), HCDRS3 (SEQ ID NO:9); LCDR1 (SEQ ID NO:10), LCDR2 (SEQ ID NO:11), and LCDR3 (SEQ ID NO:12).

[298] In various other embodiments, the target cancer antigen for an ADC is human ephrin type-A receptor 2 (EPHA2).

[299] In various embodiments, the anti-EPHA2 antibody or antigen binding fragment thereof comprises three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) consisting of SEQ ID NO:13, heavy chain CDR2 (HCDR2) consisting of SEQ ID NO:14, heavy chain CDR3 (HCDR3) consisting of SEQ ID NO:15; light chain CDR1 (LCDR1) consisting of SEQ ID NO:18, light chain CDR2 (LCDR2) consisting of SEQ ID NO:17, and light chain CDR3 (LCDR3) consisting of SEQ ID NO: 18, as defined by the Kabat numbering system.

[300] In various embodiments, the anti-EPHA2 antibody or antigen binding fragment thereof comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO:24. In some embodiments, the anti-EPHA2 antibody or antigen binding fragment thereof comprises the heavy chain variable region amino acid sequence of SEQ ID NO:23 and the light chain variable region amino acid sequence of SEQ ID NO:24, or sequences that are at least 95% identical to the disclosed sequences. In some embodiments, the anti-EPHA2 antibody or antigen binding fragment thereof has a heavy chain variable region amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:23 and / or a light chain variable region amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:24.

[301] In various embodiments, the anti-EPHA2 antibody or antigen binding fragment thereof is an internalizing antibody or internalizing antigen binding fragment. In various embodiments, the anti-EPHA2 antibody comprises a human IgG1 heavy chain constant domain and a human Ig kappa light chain constant domain.

[302] In various embodiments, the anti-EPHA2 antibody comprises the heavy chain amino acid sequence of SEQ ID NO:23 or a sequence that is at least 95% identical to SEQ ID NO:23, and the light chain amino acid sequence of SEQ ID NO:24 or a sequence that is at least 95% identical to SEQ ID NO:24. In particular embodiments, the anti-EPHA2 antibody comprises the heavy chain amino acid sequence of SEQ ID NO:23 and the light chain amino acid sequence of SEQ ID NO:24, or sequences that are at least 95% identical to the disclosed sequences. In some embodiments, the anti- EPHAZ2 antibody has a heavy chain amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:23 and a light chain amino acid sequence that is at least 96%, at least 97%, at least 98%, or at least 99% identical to SEQ ID NO:24. In some embodiments, the anti-EPHA2 antibody comprises a heavy chain encoded by the nucleotide sequence of SEQ ID NO:23; and a light chain encoded by the nucleotide sequence of SEQ ID NO:24. In various embodiments, the anti-EPHA2 antibody is 1C1, or an antigen binding fragment thereof.

[303] In various embodiments, the anti-EPHA2 antibody or antigen binding fragment thereof comprises the three heavy chain CDRs and three light chain CDRs of 1C1 or wherein the CDRs include no more than one, two, three, four, five, or six amino acid additions, deletions or substitutions of HCDR1 (SEQ ID NO:13), HCDR2 (SEQ ID NO:14), HCDR3 (SEQ ID NO: 15); LCDR1 (SEQ ID NC:16), LCDR2 (SEQ ID NO:17), and LCDR3 (SEQ ID NO: 18).

[304] In various embodiments, amino acid substitutions are of single residues. Insertions usually will be on the order of from about 1 to about 20 amino acid residues, although considerably larger insertions may be tolerated as long as biological function is retained (e.g., binding to a target antigen). Deletions usually range from about 1 to about 20 amino acid residues, although in some cases deletions may be much larger. Substitutions, deletions, insertions, or any combination thereof may be used to arrive at a final derivative or variant. Generally, these changes are done on a few amino acids to minimize the alteration of the molecule, particularly the immunogenicity and specificity of the antigen binding protein. However, larger changes may be tolerated in certain circumstances. Conservative substitutions are generally made in accordance with the following chart depicted as Table 6. Table 6 Original Residue Exemplary Substitutions Ala Ser Gly Pro His Asn, Gin lle Leu, Val Leu lle, Val Lys Arg, Gin, Glu Met Leu, lle Phe Met, Leu, Tyr Ser Thr Thr Ser Trp Tyr Tyr Trp, Phe Val lle, Leu

[305] Substantial changes in function or immunological identity are made by selecting substitutions that are less conservative than those shown in Table 6. For example, substitutions may be made which more significantly affect: the structure of the polypeptide backbone in the area of the alteration, for example the alpha-helical or beta- sheet structure; the charge or hydrophobicity of the molecule at the target site; or the bulk of the side chain. The substitutions which in general may produce the greatest changes in the polypeptide's properties are those in which (a) a hydrophilic residue, e.g., seryl or threonyl, is substituted for (or by) a hydrophobic residue, e.g., leucyl, isoleucyl, phenylalanyl, valyl or alanyl; (b) a cysteine or proline is substituted for (or by) any other residue; (c) a residue having an electropositive side chain, e.g., lysyl, arginyl, or histidyl, is substituted for (or by) an electronegative residue, e.g., glutamyl or aspartyl; or (d) a residue having a bulky side chain, e.g., phenylalanine, is substituted for (or by) one not having a side chain, e.g., glycine.

[306] In various embodiments where variant antibody sequences are used in an ADC, the variants typically exhibit the same qualitative biological activity and will elicit the same immune response, although variants may also be selected to modify the characteristics of the antigen binding proteins as needed. Alternatively, the variant may be designed such that the biological activity of the antigen binding protein is altered. For example, glycosylation sites may be altered or removed.

[307] Various antibodies may be used with the ADCs used herein to target cancer cells. As shown below, the linker-payloads in the ADCs disclosed herein are surprisingly effective with different tumor antigen-targeting antibodies. Suitable antigens expressed on tumor cells but not healthy cells, or expressed on tumor cells at a higher level than on healthy cells, are known in the art, as are antibodies directed against them. These antibodies may be used with the linkers and splicing modulator payloads disclosed herein. In some embodiments, the antibody or antigen binding fragment targets HER2, and the HER2-targeting antibody or antigen binding fragment is trastuzumab. In some embodiments, the antibody or antigen binding fragment targets CD138, and the CD138-targeting antibody or antigen binding fragment is B-B4. In some embodiments, the antibody or antigen binding fragment targets EPHA2, and the EPHAZ2-targeting antibody or antigen binding fragment is 1C1. In some embodiments, while the disclosed linkers and splicing modulator payloads are surprisingly effective with several different tumor-targeting antibodies, HER2-targeting antibodies such as trastuzumab, CD138-targeting antibodies such as B-B4, and EPHA2-targeting antibodies such as 1C1 provided particularly improved drug:antibody ratio, aggregation level, stability (i.e., in vitro and in vivo stability), tumor targeting (i.e., cytotoxicity, potency), and / or treatment efficacy. Improved treatment efficacy can be measured in vitro or in vivo, and may include reduced tumor growth rate and / or reduced tumor volume.

[308] In certain embodiments, alternate antibodies to the same targets or antibodies to different antigen targets are used and provide at least some of the favorable functional properties described above (e.g., improved stability, improved tumor targeting, improved treatment efficacy, etc.). In some embodiments, some or all of these favorable functional properties are observed when the disclosed linkers and splicing modulator payloads are conjugated to an alternate HER2-, CD138-, or EPHA2-targeting antibody or antigen binding fragment. In some other embodiments, some or all of these favorable functional properties are observed when the disclosed linkers and splicing modulator payloads are conjugated to a HER2-targeting antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment targets HER2. In some embodiments, the HER2-targeting antibody or antigen binding fragment is trastuzumab. In some other embodiments, some or all of these favorable functional properties are observed when the disclosed linkers and splicing modulator payloads are conjugated to a CD138-targeting antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment targets CD138. In some embodiments, the CD138-targeting antibody or antigen binding fragment is B-B4. In some other embodiments, some or all of these favorable functional properties are observed when the disclosed linkers and splicing modulator payloads are conjugated to an EPHA2-targeting antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment targets EPHA2. In some embodiments, the EPHA2-targeting antibody or antigen binding fragment is 1C1. Linkers

[309] In various embodiments, the linker in an ADC is stable extracellularly in a sufficient manner to be therapeutically effective. In some embodiments, the linker is stable outside a cell, such that the ADC remains intact when present in extracellular conditions (e.g., prior to transport or delivery into a cell). The term “intact,” used in the context of an ADC, means that the antibody or antigen binding fragment remains attached to the drug moiety (e.g., the splicing modulator). As used herein, “stable,” in the context of a linker or ADC comprising a linker, means that no more than 20%, no more than about 15%, no more than about 10%, no more than about 5%, no more than about 3%, or no more than about 1% of the linkers (or any percentage in between) in a sample of ADC are cleaved (or in the case of an overall ADC are otherwise not intact) when the ADC is present in extracellular conditions. In some embodiments, the linkers and / or ADCs disclosed herein are surprisingly stable compared to alternate linkers and / or ADCs with alternate linkers and / or splicing modulator payloads. In some embodiments, the ADCs disclosed herein can remain intact for more than about 48 hours, more than 60 hours, more than about 72 hours, more than about 84 hours, or more than about 96 hours.

[310] Whether a linker is stable extracellularly can be determined, for example, by including an ADC in plasma for a predetermined time period (e.g., 2, 4, 6, 8, 16, 24, 48, or 72 hours) and then quantifying the amount of free drug moiety present in the plasma. Stability may allow the ADC time to localize to target tumor cells and prevent the premature release of the drug moiety, which could lower the therapeutic index of the ADC by indiscriminately damaging both normal and tumor tissues. In some embodiments, the linker is stable outside of a target cell and releases the drug moiety from the ADC once inside of the cell, such that the drug can bind to its target (e.g., to the SF3b spliceosome complex). Thus, an effective linker will: (i) maintain the specific binding properties of the antibody or antigen binding fragment; (ii) allow delivery, e.g., intracellular delivery, of the drug moiety via stable attachment to the antibody or antigen binding fragment; (iii) remain stable and intact until the ADC has been transported or delivered to its target site; and (iv) allow for the therapeutic effect, e.g., cytotoxic effect, of the drug moiety after cleavage or alternate release mechanism.

[311] Linkers may impact the physico-chemical properties of an ADC. As many cytotoxic agents are hydrophobic in nature, linking them to the antibody with an additional hydrophobic moiety may lead to aggregation. ADC aggregates are insoluble and often limit achievable drug loading onto the antibody, which can negatively affect the potency of the ADC. Protein aggregates of biologics, in general, have also been linked to increased immunogenicity. As shown below, linkers disclosed herein result in ADCs with low aggregation levels and desirable levels of drug loading.

[312] A linker may be "cleavable" or "non-cleavable” (Ducry and Stump (2010) Bioconjugate Chem. 21:5-13). Cleavable linkers are designed to release the drug moiety (e.g., the splicing modulator) when subjected to certain environment factors, e.g., when internalized into the target cell, whereas non-cleavable linkers generally rely on the degradation of the antibody or antigen binding fragment itself.

[313] In some embodiments, the linker is a non-cleavable linker. In some embodiments, the splicing modulator drug moiety of the ADC is released by degradation of the antibody or antigen binding fragment. Non-cleavable linkers tend to remain covalently associated with at least one amino acid of the antibody and the drug upon internalization by and degradation within the target cell. Numerous exemplary non- cleavable linkers are described herein, and others are known in the art. Exemplary non- cleavable linkers may comprise thioether, cyclohexyl, N-succinimidyl 4-(N- maleimidomethyl) cyclohexane-1 carboxylate (SMCC), or N-hydroxysuccinimide (NHS), one or more polyethylene glycol (PEG) moieties, e.g., 1, 2, 3, 4, 5, or 6 PEG moieties, or one or more alkyl moieties.

[314] In some embodiments, the linker is a cleavable linker. A cleavable linker refers to any linker that comprises a cleavable moiety. As used herein, the term “cleavable moiety” refers to any chemical bond that can be cleaved. Suitable cleavable chemical bonds are well known in the art and include, but are not limited to, acid labile bonds, protease / peptidase labile bonds, photolabile bonds, disulfide bonds, and esterase labile bonds. Linkers comprising a cleavable moiety can allow for the release of the splicing modulator drug moiety from the ADC via cleavage at a particular site in the linker.

[315] In some embodiments, the linker is cleavable under intracellular conditions, such that cleavage of the linker sufficiently releases the splicing modulator drug moiety from the antibody or antigen binding fragment in the intracellular environment to activate the drug and / or render the drug therapeutically effective. In some embodiments, the splicing modulator drug moiety is not cleaved from the antibody or antigen binding fragment until the ADC enters a cell that expresses an antigen specific for the antibody or antigen binding fragment of the ADC, and the splicing modulator drug moiety is cleaved from the antibody or antigen binding fragment upon entering the cell. In some embodiments, the linker comprises a cleavable moiety that is positioned such that no part of the linker or the antibody or antigen binding fragment remains bound to the splicing modulator drug moiety upon cleavage. Exemplary cleavable linkers include acid labile linkers, protease / peptidase-sensitive linkers, photolabile linkers, dimethyl-, disulfide-, or sulfonamide-containing linkers.

[316] In some embodiments, the linker is a pH-sensitive linker, and is sensitive to hydrolysis at certain pH values. Typically, the pH-sensitive linker is cleavable under acidic conditions. This cleavage strategy generally takes advantage of the lower pH in the endosomal (pH ~ 5-8) and lysosomal (pH ~ 4.8) intracellular compartments, as compared to the cytosol (pH ~ 7.4), to trigger hydrolysis of an acid labile group in the linker, such as a hydrazone (Jain et al. (2015) Pharm Res 32:3526-40). In some embodiments, the linker is an acid labile and / or hydrolyzable linker. For example, an acid labile linker that is hydrolyzable in the lysosome, and contains an acid labile group (e.g., a hydrazone, a semicarbazone, a thiosemicarbazone, a cis-aconitic amide, an orthoester, an acetal, a ketal, or the like) can be used. See, e.g., U.S. Pat. Nos. 5,122,368; 5,824,805; 5,622,929; Dubowchik and Walker (1999) Pharm Therapeutics 83:67-123; Neville et al. (1989) Biol Chem. 264:14653-61. Such linkers are relatively stable under neutral pH conditions, such as those in the blood, but are unstable at below pH 5.5 or 5.0, the approximate pH of the lysosome. In certain embodiments, the hydrolyzable linker is a thioether linker (such as, e.g., a thioether attached to the therapeutic agent via an acylhydrazone bond) (see, e.g., U.S. Pat. No. 5,622,929).

[317] In some embodiments, the linker is cleavable under reducing conditions. In some embodiments, the linker is cleavable in the presence of a reducing agent, such as glutathione or dithiothreitol. In some embodiments, the linker is a cleavable disulfide linker or a cleavable sulfonamide linker.

[318] In some embodiments, the linker is a cleavable disulfide linker. A variety of disulfide linkers are known in the art, including, for example, those that can be formed using SATA (N-succinimidyl-5-acetylthioacetate), SPDP (N-succinimidyl-3-(2- pyridyldithio)propionate), SPDB (N-succinimidyl-3-(2-pyridyldithio)butyrate) and SMPT (N-succinimidyloxycarbonyl-alpha-methyl-alpha-(2-pyridyl-dithio)toluene), SPDB and SMPT. See, e.g., Thorpe et al. (1987) Cancer Res. 47:5924-31; Wawrzynczak et al., In Immunoconjugates: Antibody Conjugates in Radioimagery and Therapy of Cancer (C. W. Vogel ed., Oxford U. Press, 1987). See also U.S. Pat. No. 4,880,935. Disulfide linkers are typically used to exploit the abundance of intracellular thiols, which can facilitate the cleavage of their disulfide bonds. The intracellular concentrations of the most abundance intracellular thiol, reduced glutathione, are generally in the range of 1- 10 nM, which is about 1,000-fold higher than that of the most abundant low-molecular thiol in the blood (i.e., cysteine) at about 5 uM (Goldmacher et al., In Cancer Drug Discovery and Development: Antibody-Drug Conjugates and Immunotoxins (G. L. Phillips ed., Springer, 2013)). The intracellular enzymes of the protein disulfide isomerase family may also contribute to the intracellular cleavage of a disulfide linker. As used herein, a cleavable disulfide linker refers to any linker that comprises a cleavable disulfide moiety. The term “cleavable disulfide moiety” refers to a disulfide bond that can be cleaved and / or reduced, e.g., by a thiol or enzyme.

[319] In some embodiments, the linker is a cleavable sulfonamide linker. As used herein, a cleavable sulfonamide linker refers to any linker that comprises a cleavable sulfonamide moiety. The term “cleavable sulfonamide moiety” refers to a sulfonamide group, i.e., sulfonyl group connected to an amine group, wherein the sulfur-nitrogen bond can be cleaved.

[320] In some embodiments, the linker may be a dendritic type linker for covalent attachment of more than one drug moiety to an antibody or antigen binding fragment through a branching, multifunctional linker moiety. See, e.g., Sun et al. (2002) Bioorg Med Chem Lett. 12:2213-5; Sun et al. (2003) Bioorg Med Chem. 11:1761-8. Dendritic linkers can increase the molar ratio of drug to antibody, i.e., drug loading, which is related to the potency of the ADC. Thus, where an antibody or antigen binding fragment bears only one reactive cysteine thiol group, for example, a multitude of splicing modulator drug moieties may be attached through a dendritic linker. In some embodiments, the linker moiety or linker-drug moiety may be attached to the antibody or antigen binding fragment via reduced disulfide bridging chemistry or limited lysine utilization technology. See, e.g., Intl. Publ. Nos. WO 2013 / 173391 and WO 2013 / 173393.

[321] In some embodiments, the linker is cleavable by a cleaving agent, e.g., an enzyme, that is present in the intracellular environment (e.g., within a lysosome or endosome or caveola). The linker can be, e.g., a peptide linker that is cleaved by an intracellular peptidase or protease enzyme, including, but not limited to, a lysosomal or endosomal protease.

[322] In some embodiments, the linker is a cleavable peptide linker. As used herein, a cleavable peptide linker refers to any linker that comprises a cleavable peptide moiety. The term “cleavable peptide moiety” refers to any chemical bond linking amino acids (natural or synthetic amino acid derivatives) that can be cleaved by an agent that is present in the intracellular environment. For instance, a linker may comprise a valine- alanine (Val-Ala) sequence, or a valine-citrulline (Val-Cit) sequence that is cleavable by a peptidase such as cathepsin, e.g., cathepsin B. In some embodiments, a linker may comprise a glutamic acid-valine-citrulline (Glu-Val-Cit) sequence. In some embodiments, the linker is an enzyme-cleavable linker and a cleavable peptide moiety in the linker is cleavable by the enzyme. In some embodiments, the cleavable peptide moiety is cleavable by a lysosomal enzyme, e.g., cathepsin. In some embodiments, the linker is a cathepsin-cleavable linker. In some embodiments, the cleavable peptide moiety in the linker is cleavable by a lysosomal cysteine cathepsin, such as cathepsin B, C,F,H, KL OSV, X orW. Insome embodiments, the cleavable peptide moiety is cleavable by cathepsin B. An exemplary dipeptide that may be cleaved by cathepsin B is valine-citrulline (Val-Cit) (Dubowchik et al. (2002) Bioconjugate Chem. 13:855-69).

[323] In some embodiments, the linker or the cleavable peptide moiety in the linker comprises an amino acid unit. In some embodiments, the amino acid unit allows for cleavage of the linker by a protease, thereby facilitating release of the splicing modulator drug moiety from the ADC upon exposure to one or more intracellular proteases, such as one or more lysosomal enzymes (Doronina et al. (2003) Nat Biotechnol. 21:778-84; Dubowchik and Walker (1999) Pharm Therapeutics 83:67-123). Exemplary amino acid units include, but are not limited to, dipeptides, tripeptides, tetrapeptides, and pentapeptides. Exemplary dipeptides include, but are not limited to, valine-alanine (Val-Ala), valine-citrulline (Val-Cit), alanine-asparagine (Ala-Asn), alanine-phenylalanine (Ala-Phe), phenylalanine-lysine (Phe-Lys), alanine-lysine (Ala- Lys), alanine-valine (Ala-Val), valine-lysine (Val-Lys), lysine-lysine (Lys-Lys), phenylalanine-citrulline (Phe-Cit), leucine-citrulline (Leu-Cit), isoleucine-citrulline (lle- Cit), tryptophan-citrulline (Trp-Cit), and phenylalanine-alanine (Phe-Ala). Exemplary tripeptides include, but are not limited to, alanine-alanine-asparagine (Ala-Ala-Asn), glycine-valine-citrulline (Gly-Val-Cit), glycine-glycine-glycine (Gly-Gly-Gly), phenylalanine-phenylalanine-lysine (Phe-Phe-Lys), glutamic acid-valine-citrulline (Glu- Val-Cit) (see, e.g., Anami et al. (2018) Nat Comm. 2:2512, which is incorporated herein by reference for exemplary linkers comprising Glu-Val-Cit), and glycine-phenylalanine- lysine (Gly-Phe-Lys). Other exemplary amino acid units include, but are not limited to, Gly-Phe-Gly-Gly (SEQ ID NO:34), Gly-Phe-Leu-Gly (SEQ ID NO:35), Ala-Leu-Ala-Leu (SEQ ID NO:36), Phe-Ne-tosyl-Arg, and Phe-Ne-Nitro-Arg, as described in, e.g., U.S. Pat. No. 6,214,345. In some embodiments, the amino acid unit in the linker comprises Val-Ala. In some embodiments, the amino acid unit in the linker comprises Val-Cit. In some embodiments, the amino acid unit in the linker comprises Glu-Val-Cit. An amino acid unit may comprise amino acid residues that occur naturally and / or minor amino acids and / or non-naturally occurring amino acid analogs, such as citrulline. Amino acid units can be designed and optimized for enzymatic cleavage by a particular enzyme, for example, a tumor-associated protease, a lysosomal protease such as cathepsin B, C, D, or S, or a plasmin protease.

[324] In some embodiments, the linker is a cleavable B-glucuronide linker. As used herein, a cleavable B-glucuronide linker refers to any linker that comprises a cleavable B-glucuronide moiety. An exemplary cleavable B-glucuronide linker comprises the structure:

[325] The term “cleave sosidic bond that can be cleaved by an agent having B-glucuronidase activity. In some embodiments, the linker comprises a glycosidic bond that can be cleaved by a B-glucuronidase. A B- glucuronidase is a UDP-glucuronosyl transferase that catalyzes the hydrolysis of the glycosidic bond of glucuronides with B-configuration.

[326] In some embodiments, an ADC disclosed herein comprises a cleavable B- glucuronide moiety in the linker that is cleavable by the enzyme. In some embodiments, the cleavable B-glucuronide moiety in the linker is cleavable by a lysosomal enzyme, e.g., a B-glucuronidase. In some embodiments, the linker is a B-glucuronidase- cleavable linker. In some embodiments, the cleavable B-glucuronide moiety in the linker allows for cleavage of the linker by a B-glucuronidase after internalization of the ADC, thereby facilitating release of the drug moiety from the ADC in the cellular environment.

[327] In some embodiments, the linker in any of the ADCs disclosed herein may comprise at least one spacer unit joining the antibody or antigen binding fragment to the drug moiety (e.g., the splicing modulator drug moiety). In some embodiments, a spacer unit between the antibody or antigen binding fragment and cleavable moiety, when present, joins a cleavage site (e.g., a cleavable peptide moiety) in the linker to the antibody or antigen binding fragment. In some embodiments, a spacer unit between the drug moiety and cleavable moiety, when present, joins a cleavage site (e.g., a cleavable peptide moiety) in the linker to the drug moiety. In some embodiments, no cleavage site is present, and the spacer unit is used to link the antibody or antigen binding fragment to the drug moiety.

[328] In some embodiments, the linker, and / or spacer unit in the linker, is substantially hydrophilic. A hydrophilic linker may be used to reduce the extent to which the drug may be pumped out of resistant cancer cells through multiple drug resistance (MDR) or functionally similar transporters. In some embodiments, a hydrophilic linker may include one or more polyethylene glycol (PEG) moieties, e.g., 1, 2, 3, 4, 5, or 6 PEG moieties. In some embodiments, the linker comprises 2 PEG moieties.

[329] In some embodiments, the spacer unit in the linker comprises one or more PEG moieties. In some embodiments, the spacer unit comprises one or more -(PEG)-, and mis an integer from 1 to 10 (i.e, mmaybe 1,2, 3,4,5,6,7, 8, 9, or 10). In some embodiments, m ranges from 1 to 10; from 2 to 8; from 2 to 6; from 2 to 5; from 2 to 4; or from 2 to 3. In some embodiments, mis 2. In some embodiments, the spacer unit comprises (PEG)2, (PEG)s, (PEG)s, (PEG)s, (PEG)s, (PEG), (PEG)s, (PEG)s, Or (PEG)10. In some embodiments, the spacer unit comprises (PEG)a2.

[330] In some embodiments, the spacer unit in the linker comprises an alkyl moiety. In some embodiments, the spacer unit comprises one or more -(CHz)-, and n is an integer from 1 to 10 (i.e., nmay be 1, 2, 3,4, 5,6, 7, 8, 9, or 10). In some embodiments, n ranges from 1 to 10; from 2 to 8; from 2 to 6; from 2 to 5; from 2 to 4; or from 2to 3. In some embodiments, nis 2. In some embodiments, nis 5. In some embodiments, n is 6. In some embodiments, the spacer unit comprises (CHz)z, (CHz)s, (CHz)4, (CH2)s, (CHz)s, (CHz)7, (CH2)s, (CHz2)e, or (CH2)10. In some embodiments, the spacer unit comprises (CHz)2 (‘Et’). In some embodiments, the spacer unit comprises (CHz)s (“Hex”). In some embodiments, the spacer unit comprises (CHz)2-O-(CHz)z (“Et-O-Et’).

[331] A spacer unit may be used, for example, to link the antibody or antigen binding fragment to the drug moiety, either directly or indirectly. In some embodiments, the spacer unit links the antibody or antigen binding fragment to the splicing modulator drug moiety directly. In some embodiments, the antibody or antigen binding fragment and the splicing modulator drug moiety are attached via a spacer unit comprising one or more PEG moieties (e.g., (PEG)2), or one or more alkyl moieties (e.g., (CHz)z, (CHz)s, or (CH2)2-0O-(CHz)2). In some embodiments, the spacer unit links the antibody or antigen binding fragment to the splicing modulator drug moiety indirectly. In some embodiments, the spacer unit links the antibody or antigen binding fragment to the splicing modulator drug moiety indirectly through a cleavable moiety (e.g., a cleavable peptide or a cleavable B-glucuronide) and / or an attachment moiety to join the spacer unit to the antibody or antigen binding fragment, e.g., a maleimide moiety.

[332] The spacer unit, in various embodiments, attaches to the antibody or antigen binding fragment (i.e., the antibody or antigen binding fragment) via a maleimide (Mal) moiety.

[333] A spacer unit that attaches to the antibody or antigen binding fragment via a Mal is referred to herein as a “Mal-spacer unit.” The term “Mal” or “maleimide moiety,” as used herein, means a compound that contains a maleimide group and that is reactive with a sulfhydryl group, e.g., a sulfhydryl group of a cysteine residue on the antibody or antigen binding fragment. Other functional groups that are reactive with sulfhydryl groups (thiols) include, but are not limited to, iodoacetamide, bromoacetamide, vinyl pyridine, disulfide, pyridyl disulfide, isocyanate, and isothiocyanate. In some embodiments, the Mal-spacer unit is reactive with a cysteine residue on the antibody or antigen binding fragment. In some embodiments, the Mal-spacer unit is joined to the antibody or antigen binding fragment via the cysteine residue. In some embodiments, the Mal-spacer unit comprises a PEG moiety. In some embodiments, the Mal-spacer unit comprises an alkyl moiety.

[334] In certain embodiments, the linker comprises the Mal-spacer unit and a cleavable peptide moiety. In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the amino acid unit comprises Val-Cit. In some embodiments, the amino acid unit comprises Val-Ala. In some embodiments, the amino acid unit comprises Glu-Val-Cit. In some embodiments, the linker comprises the Mal-spacer unit and Val-Cit. In some embodiments, the linker comprises the Mal-spacer unit and Val-Ala. In some embodiments, the linker comprises the Mal-spacer unit and Val-Cit, wherein the Mal-spacer unit comprises a maleimidocaproyl (MC). In some embodiments, the linker comprises the Mal-spacer unit and Val-Ala, wherein the Mal-spacer unit comprises a maleimidocaproyl (MC). In some embodiments, the linker comprises the Mal-spacer unit and a cleavable B- glucuronide moiety.

[335] In some embodiments, the linker comprises the structure: Mal-spacer unit. In some embodiments, the Mal-spacer unit comprises a maleimidocaproyl (MC). In some embodiments, the linker comprises the structure: MC. In some embodiments, the linker comprises the structure: Mal-(CHz)z (‘Mal-Et"). In some embodiments, the linker comprises the structure: Mal-(CHz)e (“Mal-Hex"). In some embodiments, the linker comprises the structure: Mal-(CHz)2-O-(CHz)2 (‘Mal-Et-O-Et"). In some embodiments, the linker comprises the structure: Mal-(PEG).. In some embodiments, the linker comprises the structure: Mal-(PEG)2-CO.

[336] In various embodiments, the Mal-spacer unit attaches the antibody or antigen binding fragment to a cleavable peptide moiety. In some embodiments, the linker comprises Mal-spacer unit-peptide. In some embodiments, the linker comprises the structure: Mal-spacer unit-Val-Cit. In some embodiments, the Mal-spacer unit comprises a maleimidocaproyl (MC). In some embodiments, the linker comprises the structure: MC-Val-Cit.

[337] In some embodiments, the linker comprises the structure: Mal-spacer unit-Val- Ala. In some embodiments, the Mal-spacer unit comprises a maleimidocaproyl (MC). In some embodiments, the linker comprises the structure: MC-Val-Ala.

[338] In various embodiments, the Mal-spacer unit attaches the antibody or antigen binding fragment to a cleavable B-glucuronide moiety. In some embodiments, the linker comprises Mal-spacer unit-B-glucuronide. In some embodiments, the linker comprises MC-B-glucuronide.

[339] In various embodiments, the cleavable moiety in the linker is joined directly to the splicing modulator drug moiety. In other embodiments, a spacer unit is used to attach the cleavable moiety in the linker to the splicing modulator drug moiety. In various embodiments, the splicing modulator is attached to the cleavable moiety in the linker by a spacer unit.

[340] A spacer unit may be "self-immolative" or "non-self<immolative.” A "non-self- immolative" spacer unit is one in which part or all of the spacer unit remains bound to the splicing modulator drug moiety upon cleavage of the linker. Examples of non-self- immolative spacer units include, but are not limited to, a glycine spacer unit and a glycine-glycine spacer unit. Non-self-immolative spacer units may eventually degrade over time but do not readily release a linked native drug moiety entirely under cellular conditions. A "self-immolative” spacer unit allows for release of the native drug moiety under intracellular conditions. A “native drug” or “native drug moiety” is one where no part of the spacer unit or other chemical modification remains after cleavage / degradation of the spacer unit.

[341] Self-immolation chemistry is known in the art and could be readily selected for the disclosed ADCs. In various embodiments, the spacer unit attaching the cleavable moiety in the linker to the splicing modulator drug moiety is self-immolative, and undergoes self-immolation concurrently with or shortly before / after cleavage of the cleavable moiety under intracellular conditions. In some embodiments, the splicing modulator is attached to the cleavable moiety in the linker by a self-immolative spacer unit. In certain embodiments, the splicing modulator is attached to the cleavable moiety in the linker by a self-immolative spacer unit, the cleavable moiety comprises Val-Cit, and a maleimidocaproyl (MC) joins the cleavable moiety to the antibody or antigen binding fragment. In certain embodiments, the splicing modulator is attached to the cleavable moiety in the linker by a self-immolative spacer unit, the cleavable moiety comprises Val-Ala, and a maleimidocaproyl (MC) joins the cleavable moiety to the antibody or antigen binding fragment. In certain embodiments, the splicing modulator is attached to the cleavable moiety in the linker by a self-immolative spacer unit, the cleavable moiety comprises Glu-Val-Cit, and a maleimidocaproyl (MC) joins the cleavable moiety to the antibody or antigen binding fragment. In certain embodiments, the splicing modulator is joined to the antibody or antigen binding fragment via a Mal- spacer unit (e.g., MC) in the linker joined to a Val-Cit cleavable moiety and a pABC or PAB self-immolative spacer unit. In certain other embodiments, the splicing modulator is joined to the antibody or antigen binding fragment via a Mal-spacer unit (e.g., MC) in the linker joined to a Val-Ala cleavable moiety and a pABC or pAB self-immolative spacer unit. In certain other embodiments, the splicing modulator is joined to the antibody or antigen binding fragment via a Mal-spacer unit (e.g., MC) in the linker joined to a Glu-Val-Cit cleavable moiety and a pABC or pAB self-immolative spacer unit.

[342] In certain embodiments, the self-immolative spacer unit in the linker comprises a p-aminobenzyl unit. In some embodiments, a p-aminobenzy! alcohol (PABOH) is attached to an amino acid unit or other cleavable moiety in the linker via an amide bond, and a carbamate, methylcarbamate, or carbonate is made between the pABOH and the drug moiety (Hamann et al. (2005) Expert Opin Ther Patents 15:1087-103). In some embodiments, the self-immolative spacer unit is or comprises p- aminobenzyloxycarbonyl (pPABC). Without being bound by theory, it is thought that the self-immolation of pABC involves a spontaneous 1,6-elimination reaction (Jain et al. (2015) Pharm Res. 32:3526-40).

[343] In various embodiments, the structure of the p-aminobenzyloxycarbonyl (pPABC) used in the disclosed ADCs is sh¢

[344] In various embodiments, the self-immolative spacer unit attaches the cleavable moiety in the linker to the splicing modulator. In some embodiments, the self-immolative spacer unit is pABC. In some embodiments, the pABC attaches the cleavable moiety in the linker to the splicing modulator. In some embodiments, the pABC undergoes self- immolation upon cleavage of the cleavable moiety, and the splicing modulator is released from the ADC in its native, active form.

[345] In some embodiments, an anti-HER2 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Cit-pABC. In other embodiments, an anti-HER2 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Ala-pABC.

[346] In some embodiments, an anti-CD138 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Cit-pABC. In other embodiments, an anti-CD138 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Ala-pABC.

[347] In some embodiments, an anti-EPHA2 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Cit-pABC. In other embodiments, an anti-EPHA2 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Ala-pABC.

[348] In some embodiments, the pABC undergoes self-immolation upon cleavage of a cleavable peptide moiety in the linker. In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the linker comprises amino acid unit-pABC. In some embodiments, the amino acid unit is Val-Cit. In some embodiments, the linker comprises Val-Cit-pABC. In some embodiments, the amino acid unit is Val-Ala. In some embodiments, the linker comprises Val-Ala-pABC. In some embodiments, the amino acid unit is Glu-Val-Cit. In some embodiments, the linker comprises Glu-Val-Cit-pABC. In some embodiments, the amino acid unit is Ala- Ala-Asn. In some embodiments, the linker comprises Ala-Ala-Asn-pABC.

[349] In some embodiments, the pABC undergoes self-immolation upon cleavage of a cleavable B-glucuronide moiety in the linker. In some embodiments, the linker comprises R-glucuronide-pABC.

[350] In certain embodiments, the self-immolative spacer unit in the linker comprises a p-aminobenzyl unit. In some embodiments, the self-immolative spacer unit in the linker comprises a p-aminobenzyl (pAB). In some embodiments, the self-immolation of pAB involves a spontaneous 1,6-elimination reaction.

[351] In various embodiments, the structure of the p-aminobenzyl (PAB) used in the disclosed ADCs is shown

[352] In various embodiments, the self-immolative spacer unit attaches the cleavable moiety in the linker to the splicing modulator. In some embodiments, the self-immolative spacer unit is pAB. In some embodiments, the pAB attaches the cleavable moiety in the linker to the splicing modulator. In some embodiments, the pAB undergoes self- immolation upon cleavage of the cleavable moiety, and the splicing modulator is released from the ADC in its native, active form.

[353] In some embodiments, an anti-HER2 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Cit-pAB. In other embodiments, an anti-HER2 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Ala-pAB.

[354] In some embodiments, an anti-CD138 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Cit-pAB. In other embodiments, an anti-CD138 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Ala-pAB.

[355] In some embodiments, an anti-EPHA2 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Cit-pAB. In other embodiments, an anti-EPHA2 antibody or antigen binding fragment is joined to the splicing modulator by a linker comprising MC-Val-Ala-pAB.

[356] In some embodiments, the pAB undergoes self-immolation upon cleavage of a cleavable peptide moiety in the linker. In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the linker comprises amino acid unit-pAB. In some embodiments, the amino acid unit is Val-Cit. In some embodiments, the linker comprises Val-Cit-pAB. In some embodiments, the amino acid unit is Val-Ala. In some embodiments, the linker comprises Val-Ala-pAB. In some embodiments, the amino acid unit is Glu-Val-Cit. In some embodiments, the linker comprises Glu-Val-Cit-pAB. In some embodiments, the amino acid unit is Ala-Ala-Asn. In some embodiments, the linker comprises Ala-Ala-Asn-pAB.

[357] In some embodiments, the pAB undergoes self-immolation upon cleavage of a cleavable B-glucuronide moiety in the linker. In some embodiments, the linker comprises B-glucuronide-pAB.

[358] In some other embodiments, the splicing modulator is attached to the cleavable moiety in the linker by a non-self-immolative spacer unit. In certain embodiments, the splicing modulator is attached to the cleavable moiety in the linker by a non-self- immolative spacer unit, the cleavable moiety comprises Val-Cit, and a maleimidocaproy! (MC) joins the cleavable moiety to the antibody or antigen binding fragment. In certain embodiments, the splicing modulator is attached to the cleavable moiety in the linker by a non-self-immolative spacer unit, the cleavable moiety comprises Val-Ala, and a maleimidocaproyl (MC) joins the cleavable moiety to the antibody or antigen binding fragment.

[359] In various aspects, the antibody or antigen binding fragment of the ADC is conjugated to the splicing modulator drug moiety via a linker, wherein the linker comprises a Mal-spacer unit (e.g., MC), a cleavable amino acid unit, and a pABC. In some embodiments, the spacer unit comprises an alkyl moiety. In some embodiments, the Mal-spacer unit comprises a maleimidocaproyl (MC). In some embodiments, the linker comprises Mal-spacer unit-amino acid unit-pABC. In some embodiments, the linker comprises MC-amino acid unit-pABC. In some embodiments, the linker comprises MC-Val-Cit-pABC. In some embodiments, the linker comprises MC-Val-Ala- PABC. In some embodiments, the linker comprises MC-Glu-Val-Cit-pABC. In some embodiments, the linker comprises MC-Ala-Ala-Asn-pABC.

[360] In various other aspects, the antibody or antigen binding fragment of the ADC is conjugated to the splicing modulator drug moiety via a linker, wherein the linker comprises a Mal-spacer unit (e.g., MC), a cleavable amino acid unit, and a pAB. In some embodiments, the spacer unit comprises an alkyl moiety. In some embodiments, the Mal-spacer unit comprises a maleimidocaproyl (MC). In some embodiments, the linker comprises Mal-spacer unit-amino acid unit-pAB. In some embodiments, the linker comprises MC-amino acid unit-pAB. In some embodiments, the linker comprises MC- Val-Cit-pAB. In some embodiments, the linker comprises MC-Val-Ala-pAB. In some embodiments, the linker comprises MC-Glu-Val-Cit-pAB. In some embodiments, the linker comprises MC-Ala-Ala-Asn-pAB.

[361] In various other aspects, the antibody or antigen binding fragment of the ADC is conjugated to the splicing modulator drug moiety via a linker, wherein the linker comprises a Mal-spacer unit (e.g., MC), a cleavable B-glucuronide, and a pABC. In some embodiments, the linker comprises Mal-spacer unit-g-glucuronide-pABC. In some embodiments, the linker comprises MC-B-glucuronide-pABC.

[362] In still other aspects, the antibody or antigen binding fragment of the ADC is conjugated to the splicing modulator drug moiety via a linker, wherein the linker comprises a Mal-spacer unit (e.g., MC), a cleavable B-glucuronide, and a pAB. In some embodiments, the linker comprises Mal-spacer unit-B-glucuronide-pAB. In some embodiments, the linker comprises MC-B-glucuronide-pAB.

[363] In various embodiments, the ADC compound has Formula (1): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; D is a splicing modulator; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

[364] In some embodiments, the antibody or antigen binding fragment (Ab) of the ADC is conjugated to the splicing modulator drug moiety via a linker, wherein the linker is any of the linkers disclosed or incorporated by reference herein, or comprises one or more components of any of the linkers disclosed or incorporated by reference herein.

[365] In some embodiments, the linker comprises a cleavable moiety that is positioned such that no part of the linker or the antibody or antigen binding fragment remains bound to the splicing modulator after cleavage. In some embodiments, the cleavable moiety is a cleavable peptide moiety, e.g., an amino acid unit such as Val-Cit or Val-Ala. In some embodiments, the amino acid unit or linker comprises Val-Cit. In some embodiments, the amino acid unit or linker comprises Val-Ala. In some embodiments, the amino acid unit or linker comprises Glu-Val-Cit.

[366] In some embodiments, the linker comprises at least one spacer unit joining the antibody or antigen binding fragment to the cleavable moiety. In some embodiments, the linker comprises at least one spacer unit joining the antibody or antigen binding fragment to the drug moiety. In some embodiments, the spacer unit or linker comprises at least one alkyl moiety.

[367] In some embodiments, a spacer unit in the linker attaches to the antibody or antigen binding fragment via a Mal moiety (“Mal-spacer unit’). In some embodiments, the Mal-spacer unit comprises at least one alkyl moiety. In some embodiments, the linker comprises a maleimidocaproyl (MC). In some embodiments, the linker comprises Mal-(CHz)z (“Mal-Et). In some embodiments, the linker comprises Mal-(CHz)s (“Mal- Hex"). In some embodiments, the linker comprises Mal-(CHz)2-O-(CHz)2 (‘Mal-Et-O-Et’). In some embodiments, the linker comprises Mal-(PEG)2-CO. In some embodiments, the Mal-spacer unit attaches the antibody or antigen binding fragment to the drug moiety.

[368] In some embodiments, the Mal-spacer unit or linker comprises Mal-(PEG)2, Mal- (PEG), Mal-(PEG)4, Mal-(PEG)s, Mal-(PEG)s, Mal-(PEG)7, or Mal-(PEG)s. In some embodiments, the Mal-spacer unit or linker comprises Mal-(PEG).. In some embodiments, the Mal-spacer unit or linker comprises Mal-(PEG).-CO, Mal-(PEG)s-CO, Mal-(PEG)4-CO, Mal-(PEG)s-CO, Mal-(PEG)e-CO, Mal-(PEG)7-CO, or Mal-(PEG)s.CO. In some embodiments, the Mal-spacer unit or linker comprises Mal-(PEG).-CO. In some embodiments, the Mal-spacer unit or linker comprises Mal-(PEG).-CO and at least one additional spacer unit. In some embodiments, the Mal-(PEG)2-CO attaches the antibody or antigen binding fragment to the drug moiety. In some embodiments, linker comprises or consists of Mal-(PEG)2-CO. An example of a “Mal-(PEG)2-CO” linker is also referred to herein as “ADL2” or an “ADL2” linker.

[369] In some embodiments, the Mal-spacer unit or linker comprises MC. In some embodiments, the Mal-spacer unit or linker comprises MC and at least one additional spacer unit. In some embodiments, the MC attaches the antibody or antigen binding fragment to the drug moiety. In some embodiments, the linker comprises or consists of MC. An example of an “MC” linker is also referred to herein as “ADL10” or an “ADL10” linker.

[370] In some embodiments, the Mal-spacer unit or linker comprises Mal-(CHz)s (“Mal- Hex"). In some embodiments, the Mal-spacer unit or linker comprises Mal-Hex and at least one additional spacer unit. In some embodiments, the Mal-Hex attaches the antibody or antigen binding fragment to the drug moiety. In some embodiments, the linker comprises Mal-Hex. An example of a “Mal-Hex” linker is also referred to herein as “ADL12” or an “ADL12" linker.

[371] In some embodiments, the Mal-spacer unit or linker comprises Mal-(CHz)z (“Mal- Et’). In some embodiments, the Mal-spacer unit or linker comprises Mal-Et and at least one additional spacer unit. In some embodiments, the Mal-Et attaches the antibody or antigen binding fragment to the drug moiety. In some embodiments, the linker comprises Mal-Et. An example of a “Mal-Et” linker is also referred to herein as “ADL14” or an “ADL14” linker.

[372] In some embodiments, the Mal-spacer unit or linker comprises Mal-(CHz)2-O- (CH2)2 (“Mal-Et-O-Et"). In some embodiments, the Mal-spacer unit or linker comprises Mal-Et-O-Et and at least one additional spacer unit. In some embodiments, the Mal-Et- O-Et attaches the antibody or antigen binding fragment to the drug moiety. In some embodiments, the linker comprises Mal-Et-O-Et. An example of a “Mal-Et-O-Et” linker is also referred to herein as “ADL15” or an “ADL15” linker.

[373] In some other embodiments, the Mal-spacer unit attaches the antibody or antigen binding fragment to the cleavable moiety in the linker. In some embodiments, the cleavable moiety in the linker is a cleavable peptide moiety, e.g., an amino acid unit. In some embodiments, the cleavable peptide moiety is Val-Cit or Val-Ala. In some embodiments, the Mal-spacer unit or linker comprises MC. In some embodiments, the linker comprises MC-Val-Cit. In some embodiments, the linker comprises MC-Val-Ala. In some embodiments, the linker comprises MC-Glu-Val-Cit. In some embodiments, the linker comprises MC-Ala-Ala-Asn.

[374] In some embodiments, a spacer unit attaches the cleavable moiety in the linker to the splicing modulator. In some embodiments, the spacer unit that attaches the cleavable moiety to the splicing modulator is self-immolative.

[375] In some embodiments, the spacer unit comprises pABC. In some embodiments, the pABC attaches the cleavable moiety to the splicing modulator. In some embodiments, the cleavable moiety is a cleavable peptide moiety, e.g., an amino acid unit. In some embodiments, the linker comprises amino acid unit-pABC.

[376] In some embodiments, the linker comprises Val-Cit-pABC. In some embodiments, the linker comprises Val-Cit-pABC and a MC Mal-spacer unit joining the linker to the antibody or antigen binding fragment. In some embodiments, the linker comprises MC-Val-Cit-pABC. In some embodiments, the linker comprises MC-Val-Cit- PABC and at least one additional spacer unit. An example of an MC-Val-Cit-pABC linker is also referred to herein as “ADL1” or an “ADL1” linker.

[377] In some embodiments, the linker comprises Val-Ala-pABC. In some embodiments, the linker comprises Val-Ala-pABC and a MC Mal-spacer unit joining the linker to the antibody or antigen binding fragment. In some embodiments, the linker comprises MC-Val-Ala-pABC. In some embodiments, the linker comprises MC-Val-Ala- PABC and at least one additional spacer unit. An example of an MC-Val-Ala-pABC linker is also referred to herein as “ADL8” or an “ADLS" linker.

[378] In some embodiments, the linker comprises Glu-Val-Cit-pABC. In some embodiments, the linker comprises Glu-Val-Cit-pABC and a MC Mal-spacer unit joining the linker to the antibody or antigen binding fragment. In some embodiments, the linker comprises MC-Glu-Val-Cit-pABC. In some embodiments, the linker comprises MC-Glu- Val-Cit-pABC and at least one additional spacer unit. An example of an MC-Glu-Val- Cit-pABC linker is also referred to herein as “ADL23" or an “"ADL23" linker.

[379] In some embodiments, the linker comprises Ala-Ala-Asn-pABC. In some embodiments, the linker comprises Ala-Ala-Asn-pABC and a MC Mal-spacer unit joining the linker to the antibody or antigen binding fragment. In some embodiments, the linker comprises MC-Ala-Ala-Asn-pABC. In some embodiments, the linker comprises MC-Ala- Ala-Asn-pABC and at least one additional spacer unit. An example of an MC-Ala-Ala- Asn-pABC linker is also referred to herein as “ADL21”" or an “ADL21" linker.

[380] In some other embodiments, the spacer unit comprises pAB. In some embodiments, the pAB attaches the cleavable moiety to the splicing modulator. In some embodiments, the cleavable moiety is a cleavable peptide moiety, e.g., an amino acid unit. In some embodiments, the linker comprises amino acid unit-pAB.

[381] In some embodiments, the linker comprises Val-Ala-pAB. In some embodiments, the linker comprises Val-Ala-pAB and an MC Mal-spacer unit joining the linker to the antibody or antigen binding fragment. In some embodiments, the linker comprises MC-Val-Ala-pAB. In some embodiments, the linker comprises MC-Val-Ala- PAB and at least one additional spacer unit. An example of an MC-Val-Ala-pAB linker is also referred to herein as “ADL5” or an “ADL5” linker.

[382] In some embodiments, the linker comprises Val-Cit-pAB. In some embodiments, the linker comprises Val-Cit-pAB and an MC Mal-spacer unit joining the linker to the antibody or antigen binding fragment. In some embodiments, the linker comprises MC- Val-Cit-pAB. In some embodiments, the linker comprises MC-Val-Cit-pAB and at least one additional spacer unit. An example of an MC-Val-Cit-pAB linker is also referred to herein as “ADL7” or an “ADL?” linker.

[383] In some embodiments, the linker comprises -glucuronide-pABC. In some embodiments, the linker comprises B-glucuronide-pABC and an MC Mal-spacer unit joining the linker to the antibody or antigen binding fragment. In some embodiments, the linker comprises MC-B-glucuronide-pABC. In some embodiments, the linker comprises MC-B-glucuronide-pABC and at least one additional spacer unit. An example of an MC-B-glucuronide-pABC is also referred to herein as “ADL13" or an “ADL13” linker.

[384] In some embodiments, the linker comprises B-glucuronide-pAB. In some embodiments, the linker comprises B-glucuronide-pAB and an MC Mal-spacer unit joining the linker to the antibody or antigen binding fragment. In some embodiments, the linker comprises MC-B-glucuronide-pAB.

[385] In some embodiments, the antibody or antigen binding fragment is conjugated to the splicing modulator drug moiety via an ADL1, ADL2, ADLS, ADL6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker. It has been discovered, in various embodiments, that ADCs comprising an ADL1, ADL2, ADL5, ADL8, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker and a splicing modulator drug moiety disclosed herein demonstrate desirable properties for a therapeutic ADC. In various embodiments, these properties include, but are not limited to, effective levels of drug loading, low aggregation levels, stability under storage conditions or when in circulation in the body (e.g., serum stability), retained affinity for target-expressing cells comparable to unconjugated antibody, potent cytotoxicity against target-expressing cells, low levels of off-target cell killing, high levels of bystander killing, and / or effective in vivo anti- cancer activity, all as compared to ADCs using other linker-payloads. For instance, in various embodiments, ADCs comprising an ADL1, ADL2, ADL5, ADL6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker and a splicing modulator drug moiety disclosed herein exhibit an increased ability to inhibit growth and / or proliferation in target-expressing cells, as compared to ADCs using other linker-payloads (e.g., an ADL10 linker and a splicing modulator drug moiety). In various embodiments, ADCs comprising an ADL1, ADL2, ADLS5, ADL6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker and a splicing modulator drug moiety disclosed herein exhibit surprisingly increased in vivo stability (e.g., plasma stability), as compared to other splicing modulator-based ADCs (e.g., a thailanstatin A-based ADC, for example, as reported in Puthenveetil et al. Bioconjugate Chem. (2016) 27:1880-8).

[386] In some embodiments, the good or superior functional properties provided by the particular combination of an ADL1, ADL2, ADLS5, ADL6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker and a splicing modulator drug moiety disclosed herein may be observed with the linker-payload conjugated to, e.g., an anti-HER2 antibody such as trastuzumab; an anti-CD138 antibody such as B-B4; or an anti-EPHA2 antibody such as 1C1.

[387] In some embodiments, the ADC comprises ADL1-splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell. In some embodiments, the ADC comprises ADL2-splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell. In some embodiments, the ADC comprises ADL5-splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell. In some embodiments, the ADC comprises ADL6-splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell. In some embodiments, the ADC comprises ADL7-splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell. In some embodiments, the ADC comprises ADL12-splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell. In some embodiments, the ADC comprises ADL13- splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell. In some embodiments, the ADC comprises ADL14-splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell. In some embodiments, the ADC comprises ADL15-splicing modulator and an antibody or antigen binding fragment comprising an antibody or an antigen binding fragment thereof that retains the ability to target and internalize in a neoplastic cell.

[388] In some embodiments, the ADC comprises ADL1-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL2-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL5-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL8-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL7-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL12-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL13-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL14-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL15-splicing modulator and an antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell.

[389] In some embodiments, the antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell is an internalizing antibody or internalizing antigen binding fragment. In some embodiments, the antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell comprises three heavy chain complementarity determining regions (HCDRs) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDR3); and three light chain complementarity determining regions (LCDRs) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDR®).

[390] In some embodiments, the ADC has Formula (1): Ab-(L-D), (1) wherein: (i) Ab is an anti-HER2 antibody or antigen binding fragment thereof comprising three heavy chain complementarity determining regions (HCDRs) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDR3); and three light chain complementarity determining regions (LCDRs) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR), and SEQ ID NO:6 (LCDR3); (ii) D is a splicing modulator: (iii) L is a linker comprising ADL1, ADL2, ADLS5, ADL6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15: and (iv) pis an integer from 1 to 15.

[391] In some embodiments, the antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:20. In some embodiments, the antibody or antigen binding fragment thereof that targets a HER2-expressing neoplastic cell comprises a human IgG1 heavy chain constant domain and a human Ig kappa light chain constant domain. In some embodiments, the antibody is trastuzumab. In some embodiments, p is an integer from 1 to 10, from 2 to 8, or from 4 to 8. In some embodiments, pis 4. In some embodiments, pis 8.

[392] In some embodiments, the ADC comprises ADL1-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell. In some embodiments, the ADC comprises ADL2-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell. In some embodiments, the ADC comprises ADL5-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell. In some embodiments, the ADC comprises ADL8-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell. In some embodiments, the ADC comprises ADL7-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell. In some embodiments, the ADC comprises ADL12-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell. In some embodiments, the ADC comprises ADL13-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell. In some embodiments, the ADC comprises ADL 14-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell. In some embodiments, the ADC comprises ADL15-splicing modulator and an antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell.

[393] In some embodiments, the antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell is an internalizing antibody or internalizing antigen binding fragment. In some embodiments, the antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell comprises three heavy chain complementarity determining regions (HCDRs) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR2), and SEQ ID NO:9 (HCDR3); and three light chain complementarity determining regions (LCDRs) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDR®).

[394] In some embodiments, the ADC has Formula (1): Ab-(L-D), (1) wherein: (i) Ab is an anti-CD138 antibody or antigen binding fragment thereof comprising three heavy chain complementarity determining regions (HCDRs) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR2), and SEQ ID NO:9 (HCDRS3); and three light chain complementarity determining regions (LCDRs) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO: 12 (LCDR3); (ii) D is a splicing modulator; (iii) L is a linker comprising ADL1, ADL2, ADLS5, ADL8, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15: and (iv) pis an integer from 1 to 15.

[395] In some embodiments, the antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:22. In some embodiments, the antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell comprises a murine IgG2a heavy chain constant domain and a murine Ig kappa light chain constant domain. In some embodiments, the antibody or antigen binding fragment thereof that targets a CD138-expressing neoplastic cell comprises a human 1gG2a heavy chain constant domain and a human Ig kappa light chain constant domain. In some embodiments, the antibody is B-B4. In some embodiments, p is an integer from 1 to 10, from 2 to 8, or from 4 to 8. In some embodiments, p is 4. In some embodiments, pis 8.

[396] In some embodiments, the ADC comprises ADL1-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL2-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell. In some embodiments, the ADC comprises ADLS-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL6-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL7-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL 12-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL 13-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL14-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell. In some embodiments, the ADC comprises ADL15-splicing modulator and an antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell.

[397] In some embodiments, the antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell is an internalizing antibody or internalizing antigen binding fragment. In some embodiments, the antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell comprises three heavy chain complementarity determining regions (HCDRs) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR?2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDRs) comprising amino acid sequences of SEQ ID NO:16 (LCDR 1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDRS3).

[398] In some embodiments, the ADC has Formula (I): Ab-(L-D), (1) wherein: (i) Ab is an anti-EPHA2 antibody or antigen binding fragment thereof comprising three heavy chain complementarity determining regions (HCDRs) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDRs) comprising amino acid sequences of SEQ ID NO:16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDR3); (ii) D is a splicing modulator; (iii) L is a linker comprising ADL1, ADL2, ADLS5, ADL8, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15; and (iv) pis an integer from 1 to 15.

[399] In some embodiments, the antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:24. In some embodiments, the antibody or antigen binding fragment thereof that targets an EPHA2-expressing neoplastic cell comprises a human IgG1 heavy chain constant domain and a human Ig kappa light chain constant domain. In some embodiments, the antibody is 1C1. In some embodiments, p is an integer from 1 to 10, from 2 to 8, or from 4 to 8. In some embodiments, pis 4. In some embodiments, pis 8. Drug Moieties

[400] The drug moiety (D) of the ADCs described herein can be any chemotherapeutic agent. Useful classes of chemotherapeutic agents include, for example, modulators of RNA splicing. In certain preferred embodiments, the drug moiety is a splicing modulator. Exemplary splicing modulator compounds are described and exemplified herein.

[401] In various embodiments, the drug moiety is a splicing modulator compound of (I), or a pharmaceutically acceptable R'is chosen from absent, hydrogen, C+-Ce alkyl groups, C+-Ce alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Cs-Cs heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDa; R? is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; and R*, R, and R® are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R"7, -0-C(=0)-NRSR'8, C4-Cg alkyl groups, and -NR'SR18: R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'"; R17 is chosen from hydrogen, C1-Cs alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; and Roni No” Ov "re Ry from Ry Ry Ry Ry 3, R%, R% R8, R7, R8, RS, R'8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR$R8, C5-Cs cycloalkyl groups, C+-Cs alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Cs-Cs heterocyclyl groups, wherein at least one of R® and R? is hydrogen.

[402] In some embodiments, R' is chosen from hydrogen, C4-C4 alkyl groups, C+-C4 alkylcarboxylic acid groups, and Ca-Cs cycloalkyl groups. In some embodiments, R* is hydrogen. In some embodiments, R'is a C1-C4 alkyl group. In some embodiments, R' is methyl. In some embodiments, R' is ethyl. In some embodiments, Ris a C1-C4 alkylcarboxylic acid group. In some embodiments, R' is -CH2CH2CH2CO2H. In some embodiments, R' is a Ca-Cs cycloalkyl group. In some embodiments, R' is cycloheptyl.

[403] In some embodiments, R? is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs4 alkylalkoxy groups, C1-C4 alkylcarboxylic acid groups, and C1-Cs alkylhydroxy groups. In some embodiments, R? is chosen from hydrogen and C+-Cs alkylcarboxylic acid groups. In some embodiments, R? is hydrogen. In some embodiments, R® is a C1-Cs4 alkylcarboxylic acid group. In some embodiments, R® is -CH2CH.CO2H.

[404] In some embodiments, R* is chosen from hydrogen, hydroxyl groups, -O-(C1-C4 alkyl) groups, -O-C(=0)-(C+-C4 alkyl) groups, and C+-Cq alkyl groups. In some embodiments, R* is hydrogen. In some embodiments, R* is hydroxyl. In some embodiments, R* is a -O-(C-C4 alkyl) group. In some embodiments, R* is -OCHa. In some embodiments, R* is -OCHzCHa. In some embodiments, R* is a -O-C(=0)-(C1-Cs4 alkyl) group. In some embodiments, R* is -O-C(=0)-CHa. In some embodiments, R* is - 0O-C(=0)-CH2CHa. In some embodiments, R* is a C1-Cs alkyl group. In some embodiments, R4 is methyl. In some embodiments, R* is ethyl.

[405] In some embodiments, R® is chosen from hydrogen, hydroxyl groups, -O-(C1-C4 alkyl) groups, and C+-Cs alkyl groups. In some embodiments, RS is hydrogen. In some embodiments, R® is hydroxyl. In some embodiments, R? is a -O-(C+-C4 alkyl) group. In some embodiments, RS is a C1-Cs alkyl group.

[406] In some embodiments, R® is hydrogen. In some embodiments, R” is hydrogen. In some embodiments, R¢ is hydrogen and R7 is -O-R'7. In some embodiments, R® is hydrogen and R is -OR?, wherein R'7 is chosen from hydrogen and C'-C* alkyl groups. In some embodiments, R¢ is hydrogen and R7 is -O-R'7, wherein R'7 is hydrogen. In some embodiments, R® is -O-R'7 and R7 is hydrogen. In some embodiments, RS is -O- R' and R is hydrogen, wherein R” is chosen from hydrogen and C'-C* alkyl groups. In some embodiments, R¢ is -O-R'” and R” is hydrogen, wherein R'7 is hydrogen. In some embodiments, R® is hydrogen and R” is -NR'R®. In some embodiments, R® is hydrogen and R is -NR'*R'¢, wherein RS is H and R'® is chosen from hydrogen, R7, - C(=0)-R", and -C(=0)-O-R"". In some embodiments, R® is hydrogen and R” is - NR™R', wherein R' is H and R'® is chosen from hydrogen, R'?, -C(=0)-R"7, and - C(=0)-0-R", and wherein R'” is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, and Cs-Cs heterocyclyl groups. In some embodiments, R® is -O-R"". In some embodiments, R® is -O-C(=0)-R"". In some embodiments, R® is C1-Ce alkyl. In some embodiments, R® is C1-Cs4 alkyl. In some embodiments, R® is C1 alkyl. In some embodiments, R® is -NR'SR'¢, In some embodiments, R” is -O-R'7. In some embodiments, R7 is -O-C(=0)-R'". In some embodiments, R7 is C4-Ce alkyl. In some embodiments, R7 is C1-C4 alkyl. In some embodiments, R” is C1 alkyl. In some embodiments, R7 is -NR1SR18,

[407] In some embodiments, R® is chosen from hydrogen, hydroxyl groups, -O-(C+4-C4 alkyl) groups, and (C1-Cq4 alkyl). In some embodiments, R® is hydrogen. In some embodiments, R® is a hydroxyl group. In some embodiments, R® is an -O-(C1-Cs alkyl) group. In some embodiments, R8 is an -O-(C1 alkyl) group.

[408] In some embodiments, R'® is hydrogen. In some embodiments, R'is R'. In some embodiments, R'® is -C(=0)-R"". In some embodiments, R is -C(=0)-O-R"7.

[409] In some embodiments, R'® is hydrogen. In some embodiments, R'is R'. In some embodiments, R'® is -C(=0)-R'". In some embodiments, R'® is -C(=0)-O-R"7.

[410] In some embodiments, R'? is chosen from hydrogen, C1-Cq alkyl groups, Cs-Cs cycloalkyl groups, and Ca-Cs heterocyclyl groups. In some embodiments, R'7 is hydrogen. In some embodiments, Ris a C-Cq alkyl group. In some embodiments, R'is a C+ alkyl group. In some embodiments, R'7 is a Cs-Cs cycloalkyl group. In some embodiments, R'7 is a Ca cycloalkyl group. In some embodiments, R'7 is a C4 cycloalkyl group. In some embodiments, R'7 is a Cs cycloalkyl group. In some embodiments, R' is a Cg cycloalkyl group. In some embodiments, R'is a Ca-Cs heterocyclyl group. In some embodiments, R'is a Ca heterocyclyl group. In some embodiments, R'is a C4 heterocyclyl group. In some embodiments, R'7 is a Cs heterocyclyl group. In some embodiments, R'7 is a Cs heterocyclyl group. In some embodiments, R'7 is a C7 heterocyclyl group. In some er a Cg heterocyclyl group. embodiments, embodiments, Z is n some embodime n some embodiments, Z is n some embodime! embodiments, the ympound of Formula (ll) attaches shown in Formula (lI-A): wherein Z’ is chosen from Ran QIN Rapin Ry cand Ri : and wherein all other variables are as defined for Formula (II).

[413] In various other embodiments, the drug moiety is a splicing modulator compound (IV), or a pharmaceutically R'is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C+-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, -O-C(=0)-(C1-Ce alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C4-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; and R¢4, RS, and RE are each independently chosen from hydrogen, hydroxyl groups, - O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Ce alkyl groups; R® and R? are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R7, -0-C(=0)-NR'R'8, C4-Cg alkyl groups, and -NR'$R1S; R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-0O-R'": and R'7 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Csg heterocyclyl groups: wherein RY, R%, R¢, R%, R%, R7, R8, RS, R'¢, and R'7 are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR'SR8, Ca-Cs cycloalkyl groups, C1-Ce alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Ca-Cs heterocyclyl groups, wherein at least one of R® and R is hydrogen.

[414] In some embodiments, R' is chosen from hydrogen, C+-C4 alkyl groups, C+-Cs alkylcarboxylic acid groups, and Ca-Cg cycloalkyl groups. In some embodiments, R' is hydrogen. In some embodiments, R'is a C1-Cq alkyl group. In some embodiments, R' is methyl. In some embodiments, R'is ethyl. In some embodiments, R'is a C+-C4 alkylcarboxylic acid group. In some embodiments, R* is -CH2CH2CH2COH. In some embodiments, R' is a Ca-Cs cycloalkyl group. In some embodiments, R! is cycloheptyl.

[415] In some embodiments, R? is chosen from hydrogen, C4-C4 alkyl groups, C1-Cs alkylalkoxy groups, C4-C4 alkylcarboxylic acid groups, and C4-C4 alkylhydroxy groups. In some embodiments, R* is chosen from hydrogen and C+-Cs alkylcarboxylic acid groups. In some embodiments, R?® is hydrogen. In some embodiments, R®is a C4-Cs alkylcarboxylic acid group. In some embodiments, R® is -CH2CH2CO2H.

[416] In some embodiments, R* is chosen from hydrogen, hydroxyl groups, -O-(C1-C4 alkyl) groups, -O-C(=0)-(C+-Ca alkyl) groups, and C+-Cq alkyl groups. In some embodiments, R* is hydrogen. In some embodiments, R* is hydroxyl. In some embodiments, R* is a -O-(C-C4 alkyl) group. In some embodiments, R* is -OCHa. In some embodiments, R* is -OCH2CHa. In some embodiments, R* is a -O-C(=0)-(C1-Cs4 alkyl) group. In some embodiments, R* is -O-C(=0)-CHa. In some embodiments, R* is - 0O-C(=0)-CHzCHa. In some embodiments, R* is a C1-Cs alkyl group. In some embodiments, R* is methyl. In some embodiments, R* is ethyl.

[417] In some embodiments, R® is chosen from hydrogen, hydroxyl groups, -O-(C1-C4 alkyl) groups, and C+-Cs alkyl groups. In some embodiments, RS is hydrogen. In some embodiments, R® is hydroxyl. In some embodiments, R? is a -O-(C+-C4 alkyl) group. In some embodiments, RS is a C1-Cs alkyl group.

[418] In some embodiments, R® is hydrogen. In some embodiments, R” is hydrogen. In some embodiments, R¢ is hydrogen and R7 is -O-R'7. In some embodiments, R® is hydrogen and R is -OR?, wherein R'7 is chosen from hydrogen and C'-C* alkyl groups. In some embodiments, R¢ is hydrogen and R7 is -O-R'7, wherein R'7 is hydrogen. In some embodiments, R® is -O-R'7 and R7 is hydrogen. In some embodiments, R® is -O- R' and R is hydrogen, wherein R” is chosen from hydrogen and C'-C* alkyl groups. In some embodiments, R¢ is -O-R'” and R” is hydrogen, wherein R'7 is hydrogen. In some embodiments, R® is hydrogen and R” is -NR'R®. In some embodiments, R® is hydrogen and R is -NR'*R'¢, wherein RS is H and R'® is chosen from hydrogen, R7, - C(=0)-R"7, and -C(=0)-O-R'". In some embodiments, R® is hydrogen and R is - NR'R', wherein R'® is H and R'® is chosen from hydrogen, R', -C(=0)-R"7, and - C(=0)-O-R", and wherein R'” is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, and Cs-Cs heterocyclyl groups. In some embodiments, R® is -O-R"7. In some embodiments, R¢ is -O-C(=0)-R"". In some embodiments, R® is C1-Ce alkyl. In some embodiments, R® is C1-Cq alkyl. In some embodiments, R® is C+ alkyl. In some embodiments, R¢ is -NR'SR1€,

[419] In some embodiments, R7 is -O-R". In some embodiments, R is -O-C(=0)-R"". In some embodiments, R7 is C1-Ce alkyl. In some embodiments, R is C4-Cs4 alkyl. In some embodiments, R7 is C+ alkyl. In some embodiments, R” is -NR1*R,

[420] In some embodiments, R® is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, and (C+-Cq alkyl). In some embodiments, R® is hydrogen. In some embodiments, R® is a hydroxyl group. In some embodiments, R8 is an -O-(C+-Cs alkyl) group. In some embodiments, R8 is an -O-(C4 alkyl) group.

[421] In some embodiments, R'¢ is hydrogen. In some embodiments, R'is R'7. In some embodiments, R'3 is -C(=0)-R'”. In some embodiments, R* is -C(=0)-O-R"".

[422] In some embodiments, R'® is hydrogen. In some embodiments, R'¢ is R'7. In some embodiments, R'® is -C(=0)-R'". In some embodiments, R'® is -C(=0)-O-R"7.

[423] In some embodiments, R'7 is chosen from hydrogen, C1-Cq alkyl groups, Cs-Cs cycloalkyl groups, and Ca-Cs heterocyclyl groups. In some embodiments, R'7 is hydrogen. In some embodiments, Ris a C-Cq alkyl group. In some embodiments, R'is a C+ alkyl group. In some embodiments, R'” is a Cs-Cs cycloalkyl group. In some embodiments, R'7 is a Cs cycloalkyl group. In some embodiments, Ris a C4 cycloalkyl group. In some embodiments, R'7 is a Cs cycloalkyl group. In some embodiments, R'’ is a Cs cycloalkyl group. In some embodiments, R' is a C3-Cs heterocyclyl group. In some embodiments, R'7 is a Ca heterocyclyl group. In some embodiments, R'is a C4 heterocyclyl group. In some embodiments, R'7 is a Cs heterocyclyl group. In some embodiments, R'7 is a Ce heterocyclyl group. In some embodiments, R'7 is a C7 heterocyclyl group. In some embodiments, R'7 is a Cg heterocyclyl group.

[424] In some embodiments, the splicing modulator compound of Formula (IV) attaches to the linker L, e.g., in an ADC of Formula (1), as shown in Formula (IV-A): (IV-A). a splicing modulator compound (VI), or a pharmaceutically acceptable R' and R® are each independently chosen from hydrogen, C4-Ce alkyl groups, C1-Ce alkylalkoxy groups, Ci-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C4-Ce alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Cs-Cs heterocyclyl groups, -O-C(=0)-(C+-Cs alkyl) groups, and -CDs3; R? is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R*, R, and R® are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R"7, -0-C(=0)-NRSR'8, C4-Cg alkyl groups, -NR'*R'®, and a linker; Ris chosen from hydrogen, C1-Cs alkyl groups, -C(=0)-(C1-Cs alkyl) groups, and -CDa; R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'"; R17 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Cg heterocyclyl groups; and ais1,2,3,4,56,7,8, 9, or10; wherein RY, R%, R4, R%, R%, R7, R8, R?, R'%, R'8, R'¢, and R'7 are each independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C1-Cs alkyl groups, -O-(C+-Ce alkyl) groups, -NR*R®, C5-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Ce alkylalkoxy groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein at least one of R® and R? is hydrogen; and wherein R! and R® cannot both be absent.

[426] In some embodiments, R' is chosen from hydrogen, C+-C4 alkyl groups, C+-Cs alkylcarboxylic acid groups, and Cs-Cs cycloalkyl groups. In some embodiments, R' is hydrogen. In some embodiments, R'is a C1-C4 alkyl group. In some embodiments, R' is methyl. In some embodiments, R! is ethyl. In some embodiments, R* is a C1-C4 alkylcarboxylic acid group. In some embodiments, R' is -CH2CH2CH2CO2H. In some embodiments, R' is a C3-Cs cycloalkyl group. In some embodiments, R! is cycloheptyl.

[427] In some embodiments, R? is chosen from hydrogen, C4-C4 alkyl groups, C1-C4 alkylalkoxy groups, C1-Cq alkylcarboxylic acid groups, and C+-Cq alkylhydroxy groups. In some embodiments, R? is chosen from hydrogen and C+-Cs alkylcarboxylic acid groups. In some embodiments, R?® is hydrogen. In some embodiments, R® is a C1-Cs alkylcarboxylic acid group. In some embodiments, R® is -CH2CH2CO2H.

[428] In some embodiments, R* is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, -O-C(=0)-(C1-C4 alkyl) groups, and C+-C4 alkyl groups. In some embodiments, R* is hydrogen. In some embodiments, R* is hydroxyl. In some embodiments, R* is a -O-(C1-Cq alkyl) group. In some embodiments, R* is -OCHa. In some embodiments, R* is -OCH2CHa. In some embodiments, R* is a -O-C(=0)-(C+-C4 alkyl) group. In some embodiments, R* is -O-C(=0)-CHa. In some embodiments, R* is - O-C(=0)-CH2CHa. In some embodiments, R* is a C1-C4 alkyl group. In some embodiments, R4 is methyl. In some embodiments, R* is ethyl.

[429] In some embodiments, R® is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, and C+-C4 alkyl groups. In some embodiments, R® is hydrogen. In some embodiments, RS is hydroxyl. In some embodiments, R® is a -O-(C1-C4 alkyl) group. In some embodiments, RS is a C1-C. alkyl group.

[430] In some embodiments, R® is chosen from absent, hydrogen, C+-C, alkyl groups, - (C=0)-(C+-C4 alkyl) groups, and -CDs. In some embodiments, R® is absent. In some embodiments, R? is hydrogen. In some embodiments, R¢ is a C+-C4 alkyl group. In some embodiments, the C-C4 alkyl group is methyl. In some embodiments, the C1-C4 alkyl group is ethyl. In some embodiments, R? is a -(C=0)-(C1-C. alkyl) group. In some embodiments, the -(C=0)-(C1-C4 alkyl) group is -(C=0O)-methyl. In some embodiments, R® is -CDs.

[431] In some embodiments, R'® is chosen from hydrogen, C1-C4 alkyl groups, -(C=0)- (C4-Cs alkyl) groups, and -CDs. In some embodiments, R'® is hydrogen. In some embodiments, R' is a C4-C4 alkyl group. In some embodiments, the C1-C4 alkyl group is methyl. In some embodiments, the C4-Ca4 alkyl group is ethyl. In some embodiments, R'is a -(C=0)-(C1-C4 alkyl) group. In some embodiments, the -(C=0)-(C1-C4 alkyl) group is -(C=0)-methyl. In some embodiments, R'° is -CDs.

[432] In some embodiments, R® is hydrogen. In some embodiments, R” is hydrogen. In some embodiments, R¢ is hydrogen and R7 is -O-R'7. In some embodiments, R® is hydrogen and R is -OR?, wherein R'7 is chosen from hydrogen and C'-C* alkyl groups. In some embodiments, R¢ is hydrogen and R7 is -O-R'7, wherein R'7 is hydrogen. In some embodiments, R® is -O-R'7 and R7 is hydrogen. In some embodiments, R® is -O- R'7 and R7 is hydrogen, wherein R'? is chosen from hydrogen and C'-C* alkyl groups. In some embodiments, R® is -O-R'? and R7 is hydrogen, wherein R'7 is hydrogen. In some embodiments, R® is hydrogen and R” is -NR'¢R 8. In some embodiments, R® is hydrogen and R is -NR'*R'¢, wherein RS is H and R'® is chosen from hydrogen, R7, - C(=0)-R", and -C(=0)-O-R"". In some embodiments, R® is hydrogen and R” is - NR™R', wherein R' is H and R'® is chosen from hydrogen, R'?, -C(=0)-R"7, and - C(=0)-0-R", and wherein R'” is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, and Cs-Cs heterocyclyl groups. In some embodiments, R® is -O-R"". In some embodiments, R¢ is -O-C(=0)-R". In some embodiments, R® is C+-Ce alkyl. In some embodiments, R® is C1-Cs4 alkyl. In some embodiments, R® is C1 alkyl. In some embodiments, R® is -NR'SR1®,

[433] In some embodiments, R? is -O-R'. In some embodiments, R7 is -O-C(=0)-R. In some embodiments, R” is C1-Ce alkyl. In some embodiments, R? is C4-Cs alkyl. In some embodiments, R” is C1 alkyl. In some embodiments, R” is -NRR®,

[434] In some embodiments, RE is chosen from hydrogen, hydroxyl groups, -O-(C1-C4 alkyl) groups, and (C1-Cs alkyl). In some embodiments, R® is hydrogen. In some embodiments, Re is a hydroxyl group. In some embodiments, R8 is an -O-(C1-C4 alkyl) group. In some embodiments, R8 is an -O-(C+ alkyl) group.

[435] In some embodiments, R'S is hydrogen. In some embodiments, R'® is R'7. In some embodiments, R'® is -C(=0)-R"”. In some embodiments, RS is -C(=0)-O-R"7.

[436] In some embodiments, R'® is hydrogen. In some embodiments, R'® is R'7. In some embodiments, R18 is -C(=0)-R'?. In some embodiments, R'® is -C(=0)-O-R"".

[437] In some embodiments, R'7 is chosen from hydrogen, C1-Cq alkyl groups, Cs-Cs cycloalkyl groups, and Ca-Cs heterocyclyl groups. In some embodiments, R'7 is hydrogen. In some embodiments, Ris a C-Cq alkyl group. In some embodiments, R'is a C+ alkyl group. In some embodiments, R'” is a Cs-Cs cycloalkyl group. In some embodiments, R'7 is a Cs cycloalkyl group. In some embodiments, Ris a C4 cycloalkyl group. In some embodiments, R'7 is a Cs cycloalkyl group. In some embodiments, R" is a Cs cycloalkyl group. In some embodiments, R'is a C3-Cs heterocyclyl group. In some embodiments, R'7 is a Ca heterocyclyl group. In some embodiments, R'is a C4 heterocyclyl group. In some embodiments, R'7 is a Cs heterocyclyl group. In some embodiments, R'7 is a Ce heterocyclyl group. In some embodiments, R'7 is a C7 heterocyclyl group. In some embodiments, R'7 is a Cg heterocyclyl group.

[438] In some embodiments, ais 1,2, 3,4, 5,6, 7, 8,9, or 10. In some embodiments, ais 1,2, 3,4,5 or6. In some embodiments, ais 1,2, 3,4, or 5. In some embodiments, ais 1, 2, 3, or 4. In some embodiments, ais 1, 2, or 3. In some embodiments, ais 1 or 2. In some embodiments, ais 1. In some embodiments, a is 2. In some embodiments, a is 3. In some embodiments, ais 4. In some embodiments, a is 5. In some embodiments, ais 8. In some embodiments, ais 7. In some embodiments, a is 8. In some embodiments, ais 9. In some embodiments, ais 10.

[439] In some embodiments, the splicing modulator compound of Formula (VI) as shown in Formula (VI-A): A). is a splicing modulator compound of Formula (VIII): (VIII), or a pharmaceutically acceptable salt thereof, R'is chosen from absent, hydrogen, C+-Ce alkyl groups, C+-Ce alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Cs-Cs heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDa; R? is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R* is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, -O-C(=0)- (C1-Cs alkyl) groups, and C4-Cs alkyl groups: and R10 is chosen from 3 to 10 membered carbocycles and 3 to 10 membered heterocycles, each of which is substituted with 0 to 3 R#, wherein each R? is independently chosen from halogens, C+-Cs alkyl groups, -O-(C-Ce)alkyl groups, C+-Cs alkylalkoxy groups, C4-Ce alkylhydroxy groups, -S(=0)w-(4 to 7 membered heterocycles), 4 to 7 membered carbocycles, and 4 to 7 membered heterocycles; RS and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-O-R'": and R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein R', R%, R4, R', R$, R'8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C+-Ce alkyl groups, -O-(C+-Cs alkyl) groups, -NR'$R'®, Ca-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Cs alkylalkoxy groups, benzyl groups, and Ci-Cg heterocyclyl groups; and wherein each R# is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, -NR13R18, C+-Cs alkyl groups, -(C=0)-(C1-Cs alkyl) groups, -(C=0)-(C1-Cs alkyl)-(Cs-C10 heterocyclyl groups), and C+-Ce alkylcarboxylic acid groups, each of which is substituted with 0, 1, or 2 groups independently chosen from halogens, hydroxyl groups, -NR'R8, and C+-Cs alkyl groups; and wis 0, 1, or2.

[441] In some embodiments, R' is chosen from absent, hydrogen, C+-C4 alkyl groups, C4-Cs alkylcarboxylic acid groups, and Ca-Cs cycloalkyl groups. In some embodiments, R'is hydrogen. In some embodiments, R'is a C4-Cs alkyl group. In some embodiments, R is methyl. In some embodiments, R' is ethyl. In some embodiments, R'is a C1-C4 alkylcarboxylic acid group. In some embodiments, R! is -CH2CH2CH2CO2H. In some embodiments, R' is a Cs-Cs cycloalkyl group. In some embodiments, R' is cycloheptyl.

[442] In some embodiments, R? is chosen from hydrogen, C+-Ca alkyl groups, C1-Cs alkylalkoxy groups, C+-Cs alkylcarboxylic acid groups, and C1-Cs alkylhydroxy groups. In some embodiments, R? is chosen from hydrogen and C+-Cs alkylcarboxylic acid groups. In some embodiments, R?® is hydrogen. In some embodiments, R®is a C1-Cs alkylcarboxylic acid group. In some embodiments, R® is -CH2CHzCO:H.

[443] In some embodiments, R* is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, -O-C(=0)-(C1-C4 alkyl) groups, and C+-C4 alkyl groups. In some embodiments, R* is hydrogen. In some embodiments, R* is hydroxyl. In some embodiments, R* is a -O-(C-C4 alkyl) group. In some embodiments, R* is -OCHa. In some embodiments, R* is -OCH2CHa. In some embodiments, R* is a -O-C(=0)-(C+-Cs alkyl) group. In some embodiments, R* is -O-C(=0)-CHa. In some embodiments, R* is - O-C(=0)-CH2CHa. In some embodiments, R* is a C1-Cs alkyl group. In some embodiments, R4 is methyl. In some embodiments, R* is ethyl.

[444] In some embodiments, R'® is chosen from 6 to 9 membered carbocycles and 6 to 9 membered heterocycles, each of which is substituted with 0 to 2 R?, wherein each R# is independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C4-Cs alkyl groups, -(C=0)-(C1-Cs alkyl) groups, -(C=0)-(C+-Cs alkyl)-(3 to 10 membered heterocycle) groups, and C+-Ce alkylcarboxylic acid groups.

[445] In some embodiments, the carbocycle is a phenyl substituted with 0 to 2 Ra, wherein each Re is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C+-Cs alkyl groups, -(C=0)-(C+-Cs alkyl) groups, - (C=0)-(C+-Cs alkyl)-(3 to 10 membered heterocycle) groups, and C1-Ce alkylcarboxylic acid groups. In some embodiments, the phenyl is substituted with 2 R?, wherein each Re is independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C1-Cs alkyl groups, -(C=0)-(C+-Cg alkyl) groups, -(C=0)-(C1-Ce alkyl)-(3 to 10 membered heterocy C1-Ce alkylcarboxylic acid groups. In some embodiments, the phenyl

[446] In some embodim¢ ycle is a 9 membered heterocycle substituted with 0 to 2 R?, wherein each R? is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Cs alkyl groups, -(C=0)- (C1-Cs alkyl) groups, -(C=0)-(C1-Ce alkyl)-(3 to 10 membered heterocycle) groups, and C4-Ce alkylcarboxylic acid groups. In some embodiments, the 9 membered heterocycle

[447] In some embodiments, R? is chosen from halogens, 3 to 10 membered carbocycles, and 3 to 10 membered heterocycles, wherein each R? is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -(C=0)-(C1-Cs alkyl) groups, -(C=0)-(C+-Cs alkyl)-(3 to 10 membered heterocycle) groups, and C+-Cs alkylcarboxylic acid groups. In some embodiments, Ra ~ Now N= =N Q \ CLA | | & No NY I | SN ralogens, embodiments, R' is hydrogen. In some embodiments, R'is R'. In some embodiments, R'® is -C(=0)-R"". In some embodiments, R is -C(=0)-O-R"7.

[449] In some embodiments, R'® is hydrogen. In some embodiments, R'is R'. In some embodiments, R'® is -C(=0)-R'". In some embodiments, R'® is -C(=0)-O-R"7.

[450] In some embodiments, R'7 is chosen from hydrogen, C1-Cq alkyl groups, Cs-Cs cycloalkyl groups, and Ca-Cs heterocyclyl groups. In some embodiments, R'7 is hydrogen. In some embodiments, Ris a C-Cq alkyl group. In some embodiments, R17 is a C4 alkyl group. In some embodiments, R'7 is a C3-Cs cycloalkyl group. In some embodiments, R'7 is a Cs cycloalkyl group. In some embodiments, R7 is a C4 cycloalkyl group. In some embodiments, R'7 is a Cs cycloalkyl group. In some embodiments, R' is a Cs cycloalkyl group. In some embodiments, R' is a C3-Cs heterocyclyl group. In some embodiments, R'7 is a Ca heterocyclyl group. In some embodiments, R'is a C4 heterocyclyl group. In some embodiments, R'7 is a Cs heterocyclyl group. In some embodiments, R'7 is a Ce heterocyclyl group. In some embodiments, R'7 is a C7 heterocyclyl group. In some embodiments, R'7 is a Ce heterocyclyl group.

[451] In some embodiments, the splicing modulator compound of Formula (VIII) in ADC of Formula (1), as shown in Formula (VIII-A): A). the drug moiety is a splicing modulator selected from D2 and D1.

[453] In various embodiments, the drug moiety is D2. In various embodiments, the structure of the D2 drug below:

[454] In various embodiments, the linker in the ADCs (e.g., ADCs of Formula (1)) described herein covalently attaches to the D2 drug moiety via an amine on the piperazine group. In various embodiments, the drug moiety is a derivative of D2. In various embodiments, the D2 derivative retains at least one biological function or activity as D2 (e.g., SF3b complex binding, in vitro splicing activity, cytotoxicity) but has an altered chemical structure.

[455] In various embodiments, the drug moiety is D1 or a pharmaceutically acceptable salt thereof. In various embodiments, the structure of the D1 drug moiety used in the disclosed ADCs is shown below:

[456] In various embodiments, the linker in the ADCs (e.g., ADCs of Formula (1)) described herein covalently attaches to the D1 drug moiety via an amine on the piperazine group. In various embodiments, the drug moiety is a derivative of D1. In various embodiments, the D1 derivative retains at least one biological function or activity as D1 (e.g., SF3b complex binding, in vitro splicing activity, cytotoxicity) but has an altered chemical structure.

[457] In some embor D1: 1).

[458] In some embor D2: (D2).

[459] In some embodir 3 D3:

[460] In some embodir 3 D4: (D34).

[492] In some embo smprises D35: (D35).

[493] An exemplary Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; Dis D2; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

[494] In some embodiments, the antibody or antigen binding fragment targets a cell expressing HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A8, SLC44A4, and / or STEAP1.

[495] In some embodiments, the antibody or antigen binding fragment targets a HER2- expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR?2), and SEQ ID NO:3 (HCDR3); and three light chain complementarity determining regions (LCDR 1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDRS3). In some embodiments, the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:20. In some embodiments, the antibody or antigen binding fragment comprises a human 1gG1 heavy chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a human |g kappa light chain constant region.

[496] In some other embodiments, the antibody or antigen binding fragment targets a CD138-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-CD138 antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR2), and SEQ ID NO:9 (HCDRB3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDR3). In some embodiments, the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:22. In some embodiments, the antibody or antigen binding fragment comprises a murine 19G2a heavy chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a murine Ig kappa light chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a human IgG2a heavy chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

[497] In some other embodiments, the antibody or antigen binding fragment targets an EPHA2-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-EPHA2 antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDR3). In some embodiments, the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:24. In some embodiments, the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

[498] In some other embodiments, the antibody or antigen binding fragment targets a MSLN-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-MSLN antibody or antigen binding fragment.

[499] In some other embodiments, the antibody or antigen binding fragment targets a FOLH1-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-FOLH1 antibody or antigen binding fragment.

[500] In some other embodiments, the antibody or antigen binding fragment targets a CDH8-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-CDH®6 antibody or antigen binding fragment.

[501] In some other embodiments, the antibody or antigen binding fragment targets a CEACAMS-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-CEACAMS antibody or antigen binding fragment.

[502] In some other embodiments, the antibody or antigen binding fragment targets a CFC1B-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-CFC1B antibody or antigen binding fragment.

[503] In some other embodiments, the antibody or antigen binding fragment targets an ENPP3-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-ENPP3 antibody or antigen binding fragment.

[504] In some other embodiments, the antibody or antigen binding fragment targets a FOLR1-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-FOLR1 antibody or antigen binding fragment.

[505] In some other embodiments, the antibody or antigen binding fragment targets a HAVCR1-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-HAVCR1 antibody or antigen binding fragment.

[506] In some other embodiments, the antibody or antigen binding fragment targets a KIT-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-KIT antibody or antigen binding fragment.

[507] In some other embodiments, the antibody or antigen binding fragment targets a MET-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-MET antibody or antigen binding fragment.

[508] In some other embodiments, the antibody or antigen binding fragment targets a MUC16-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-MUC 16 antibody or antigen binding fragment.

[509] In some other embodiments, the antibody or antigen binding fragment targets a SLC39A6-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-SLC39A6 antibody or antigen binding fragment.

[510] In some other embodiments, the antibody or antigen binding fragment targets a SLC44A4-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-SLC44A4 antibody or antigen binding fragment.

[511] In some other embodiments, the antibody or antigen binding fragment targets a STEAP1-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-STEAP1 antibody or antigen binding fragment.

[512] In some embodiments, L is selected from any of the linkers disclosed herein, or any combination of linker components disclosed herein. In some embodiments, L is a linker comprising MC-Val-Cit-pABC, Mal-(PEG)2-CO, MC-Val-Ala-pAB, MC-Val-Ala- PABC, MC-Val-Cit-pAB, Mal-Hex, Mal-Et, or Mal-Et-O-Et. In some embodiments, the linker may also comprise one or more additional spacer units. In some embodiments, L is an ADL1, ADL2, ADL5, ADL6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker. In some embodiments, L is an ADL12, ADL14, or ADL15 linker. In some embodiments, the ADL1, ADL2, ADLS, ADL6, ADL7, ADL12, ADL13, ADL14, ADL21, ADL23, or ADL15 linker may also comprise one or more additional spacer units.

[513] Another exemplary ADC has Formula (1): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; Dis D1; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

[514] In some embodiments, the antibody or antigen binding fragment targets a cell expressing HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC18, SLC39A6, SLC44A4, and / or STEAP1.

[515] In some embodiments, the antibody or antigen binding fragment targets a HER2- expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR?2), and SEQ ID NO:3 (HCDR3); and three light chain complementarity determining regions (LCDR 1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDRS3). In some embodiments, the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:20. In some embodiments, the antibody or antigen binding fragment comprises a human 1gG1 heavy chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a human |g kappa light chain constant region.

[516] In some other embodiments, the antibody or antigen binding fragment targets a CD138-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-CD138 antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR2), and SEQ ID NO:9 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDR3). In some embodiments, the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:22. In some embodiments, the antibody or antigen binding fragment comprises a murine 1gG2a heavy chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a murine Ig kappa light chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a human IgG2a heavy chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

[517] In some other embodiments, the antibody or antigen binding fragment targets an EPHA2-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-EPHA2 antibody or antigen binding fragment. In some embodiments, the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDR3). In some embodiments, the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:24. In some embodiments, the antibody or antigen binding fragment comprises a human |gG1 heavy chain constant region. In some embodiments, the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

[518] In some other embodiments, the antibody or antigen binding fragment targets a MSLN-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-MSLN antibody or antigen binding fragment.

[519] In some other embodiments, the antibody or antigen binding fragment targets a FOLH1-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-FOLH1 antibody or antigen binding fragment.

[520] In some other embodiments, the antibody or antigen binding fragment targets a CDH8-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-CDH®6 antibody or antigen binding fragment.

[521] In some other embodiments, the antibody or antigen binding fragment targets a CEACAMS-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-CEACAMS antibody or antigen binding fragment.

[522] In some other embodiments, the antibody or antigen binding fragment targets a CFC1B-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-CFC1B antibody or antigen binding fragment.

[523] In some other embodiments, the antibody or antigen binding fragment targets an ENPP3-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-ENPP3 antibody or antigen binding fragment.

[524] In some other embodiments, the antibody or antigen binding fragment targets a FOLR1-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-FOLR1 antibody or antigen binding fragment.

[525] In some other embodiments, the antibody or antigen binding fragment targets a HAVCR1-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-HAVCR1 antibody or antigen binding fragment.

[526] In some other embodiments, the antibody or antigen binding fragment targets a KIT-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-KIT antibody or antigen binding fragment.

[527] In some other embodiments, the antibody or antigen binding fragment targets a MET-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-MET antibody or antigen binding fragment.

[528] In some other embodiments, the antibody or antigen binding fragment targets a MUC16-expressing cell. In some embodiments, the antibody or antigen binding fragment is an anti-MUC 16 antibody or antigen binding fragment.

[529] In some other embodiments, the antibody or antigen binding fragment targets a SLC39A6-expressing cell. In some embodiments, the antibody or antigen bi...

Claims

CLAIMS 1. An antibody-drug conjugate of Formula (I): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; D is a splicing modulator: L is a linker which covalently attaches Ab to D; and pis an integer from 1 to 15.

2. The antibody-drug conjugate of claim 1, wherein the antibody or antigen binding fragment targets a neoplastic cell derived from a hematological malignancy or a solid tumor.

3. The antibody-drug conjugate of claim 1 or claim 2, wherein the antibody or antigen binding fragment targets a neoplastic cell derived from a hematological malignancy.

4. The antibody-drug conjugate of claim 3, wherein the hematological malignancy is selected from a B-cell malignancy, a leukemia, a lymphoma, and a myeloma.

5. The antibody-drug conjugate of claim 3 or claim 4, wherein the hematological malignancy is selected from acute myeloid leukemia and multiple myeloma.

6. The antibody-drug conjugate of claim 1 or claim 2, wherein the antibody or antigen binding fragment targets a neoplastic cell derived from a solid tumor. % The antibody-drug conjugate of claim 8, wherein the solid tumor is selected from breast cancer, gastric cancer, prostate cancer, ovarian cancer, lung cancer, uterine cancer, salivary duct carcinoma, melanoma, colon cancer, cervical cancer, pancreatic cancer, kidney cancer, colorectal cancer, and esophageal cancer.

8. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a HER2-expressing cell.

9. The antibody-drug conjugate of claim 8, wherein the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment.

10. The antibody-drug conjugate of claim 8 or claim 9, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDRS3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDR3).

11. The antibody-drug conjugate of any one of claims 8 to 10, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

20.

12. The antibody-drug conjugate of any one of claims 8 to 11, wherein the antibody or antigen binding fragment comprises a human 1gG1 heavy chain constant region.

13. The antibody-drug conjugate of any one of claims 8 to 12, wherein the antibody or antigen binding fragment comprises a human |g kappa light chain constant region.

14. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a CD138-expressing cell.

15. The antibody-drug conjugate of claim 14, wherein the antibody or antigen binding fragment is an anti-CD138 antibody or antigen binding fragment.

16. The antibody-drug conjugate of claim 14 or claim 15, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR2), and SEQ ID NO:9 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDR3).

17. The antibody-drug conjugate of any one of claims 14 to 16, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

22.

18. The antibody-drug conjugate of any one of claims 14 to 17, wherein the antibody or antigen binding fragment comprises a human 1gG2a heavy chain constant region.

19. The antibody-drug conjugate of any one of claims 14 to 18, wherein the antibody or antigen binding fragment comprises a human |g kappa light chain constant region.

20. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets an EPHA2-expressing cell.

21. The antibody-drug conjugate of claim 20, wherein the antibody or antigen binding fragment is an anti-EPHAZ2 antibody or antigen binding fragment.

22. The antibody-drug conjugate of claim 20 or claim 21, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDRS3).

23. The antibody-drug conjugate of any one of claims 20 to 22, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

24.

24. The antibody-drug conjugate of any one of claims 20 to 23, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

25. The antibody-drug conjugate of any one of claims 20 to 24, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

26. The antibody-drug conjugate of any one of claims 1 to 25, wherein the linker is a cleavable linker.

27. The antibody-drug conjugate of claim 26, wherein the linker comprises a cleavable peptide moiety.

28. The antibody-drug conjugate of claim 27, wherein the cleavable peptide moiety is cleavable by an enzyme.

29. The antibody-drug conjugate of any one of claims 26 to 28, wherein the cleavable peptide moiety or linker comprises an amino acid unit.

30. The antibody-drug conjugate of claim 29, wherein the amino acid unit comprises valine-citrulline (Val-Cit).

31. The antibody-drug conjugate of claim 29, wherein the amino acid unit comprises valine-alanine (Val-Ala).

32. The antibody-drug conjugate of claim 26, wherein the linker comprises a cleavable glucuronide moiety.

33. The antibody-drug conjugate of claim 32, wherein the cleavable glucuronide moiety is cleavable by an enzyme.

34. The antibody-drug conjugate of claim 32 or claim 33, wherein the cleavable glucuronide moiety is cleavable by a glucuronidase.

35. The antibody-drug conjugate of any one of claims 32 to 34, wherein the cleavable glucuronide moiety is cleavable by B-glucuronidase.

36. The antibody-drug conjugate of any one of claims 1 to 35, wherein the linker comprises at least one spacer unit.

37. The antibody-drug conjugate of claim 36, wherein the spacer unit or linker comprises a polyethylene glycol (PEG) moiety.

38. The antibody-drug conjugate of claim 37, wherein the PEG moiety comprises - (PEG) and mis an integer from 1 to 10.

39. The antibody-drug conjugate of claim 38, wherein mis 2.

40. The antibody-drug conjugate of claim 36, wherein the spacer unit or linker comprises an alkyl moiety.

41. The antibody-drug conjugate of claim 40, wherein the alkyl moiety comprises -(CH2)s~ and nis an integer from 1 to 10.

42. The antibody-drug conjugate of claim 41, wherein nis 2.

43. The antibody-drug conjugate of claim 41, wherein nis 5.

44. The antibody-drug conjugate of claim 41, wherein n is 6.

45. The antibody-drug conjugate of any one of claims 36 to 44, wherein the spacer unit attaches to the antibody or antigen binding fragment via a maleimide (Mal) moiety (“Mal-spacer unit”).

46. The antibody-drug conjugate of claim 45, wherein the Mal-spacer unit is reactive with a cysteine residue on the antibody or antigen binding fragment.

47. The antibody-drug conjugate of claim 45 or claim 46, wherein the Mal-spacer unit is joined to the antibody or antigen binding fragment via a cysteine residue on the antibody or antigen binding fragment.

48. The antibody-drug conjugate of any one of claims 45 to 47, wherein the linker comprises the Mal-spacer unit and a cleavable peptide moiety.

49. The antibody-drug conjugate of claim 48, wherein the cleavable peptide moiety comprises an amino acid unit.

50. The antibody-drug conjugate of claim 48 or claim 49, wherein the cleavable peptide moiety or amino acid unit comprises Val-Cit.

51. The antibody-drug conjugate of claim 48 or claim 49, wherein the cleavable peptide moiety or amino acid unit comprises Val-Ala.

52. The antibody-drug conjugate of any one of claims 45 to 51, wherein the Mal- spacer unit comprises an alkyl moiety.

53. The antibody-drug conjugate of any one of claims 45 to 51, wherein the Mal- spacer unit comprises a PEG moiety.

54. The antibody-drug conjugate of any one of claims 45 to 52, wherein the Mal- spacer unit comprises a maleimidocaproyl (MC).

55. The antibody-drug conjugate of any one of claims 45 to 54, wherein the Mal- spacer unit attaches the antibody or antigen binding fragment to the cleavable moiety in the linker.

56. The antibody-drug conjugate of claim 55, wherein the cleavable moiety in the linker comprises a cleavable peptide moiety.

57. The antibody-drug conjugate of claim 56, wherein the cleavable peptide moiety comprises an amino acid unit.

58. The antibody-drug conjugate of claim 56 or claim 57, wherein the cleavable peptide moiety or amino acid unit comprises Val-Cit, Val-Ala, Glu-Val-Cit, or Ala-Ala- Asn.

59. The antibody-drug conjugate of any one of claims 55 to 58, wherein the linker comprises MC-Val-Cit.

80. The antibody-drug conjugate of any one of claims 55 to 58, wherein the linker comprises MC-Val-Ala.

61. The antibody-drug conjugate of any one of claims 55 to 60, wherein the Mal- spacer unit comprises an alkyl moiety.

62. The antibody-drug conjugate of any one of claims 55 to 60, wherein the Mal- spacer unit comprises a PEG moiety.

83. The antibody-drug conjugate of any one of claims 55 to 61, wherein the Mal- spacer unit comprises a maleimidocaproyl (MC).

64. The antibody-drug conjugate of any one of claims 36 to 63, wherein the cleavable moiety in the linker is directly joined to the splicing modulator, or wherein a spacer unit attaches the cleavable moiety in the linker to the splicing modulator.

65. The antibody-drug conjugate of claim 64, wherein cleavage of the conjugate releases the splicing modulator from the antibody or antigen binding fragment and linker.

66. The antibody-drug conjugate of claim 64 or claim 65, wherein the spacer unit attaching the cleavable moiety in the linker to the splicing modulator is self-immolative.

67. The antibody-drug conjugate of any one of claims 64 to 66, wherein the spacer unit attaching the cleavable moiety in the linker to the splicing modulator comprises a p- aminobenzyloxycarbonyl (pABC).

68. The antibody-drug conjugate of claim 67, wherein the pABC attaches the cleavable moiety in the linker to the splicing modulator.

69. The antibody-drug conjugate of claim 67 or claim 68, wherein the cleavable moiety in the linker comprises a cleavable peptide moiety.

70. The antibody-drug conjugate of claim 69, wherein the cleavable peptide moiety comprises an amino acid unit.

71. The antibody-drug conjugate of claim 69 or claim 70, wherein the cleavable peptide moiety or amino acid unit comprises Val-Cit, Val-Ala, Glu-Val-Cit, or Ala-Ala- Asn.

72. The antibody-drug conjugate of any one of claims 67 to 71, wherein the linker comprises Val-Cit-pABC.

73. The antibody-drug conjugate of any one of claims 87 to 71, wherein the linker comprises Val-Ala-pABC.

74. The antibody-drug conjugate of any one of claims 64 to 66, wherein the spacer unit attaching the cleavable moiety in the linker to the splicing modulator comprises a p- aminobenzyl (pAB).

75. The antibody-drug conjugate of claim 74, wherein the pAB attaches the cleavable moiety in the linker to the splicing modulator.

76. The antibody-drug conjugate of claim 74 or claim 75, wherein the cleavable moiety in the linker comprises a cleavable peptide moiety.

77. The antibody-drug conjugate of claim 76, wherein the cleavable peptide moiety comprises an amino acid unit.

78. The antibody-drug conjugate of claim 76 or claim 77, wherein the cleavable peptide moiety or amino acid unit comprises Val-Cit, Val-Ala, Glu-Val-Cit, or Ala-Ala- Asn.

79. The antibody-drug conjugate of any one of claims 74 to 78, wherein the linker comprises Val-Cit-pAB.

80. The antibody-drug conjugate of any one of claims 74 to 78, wherein the linker comprises Val-Ala-pAB.

81. The antibody-drug conjugate of any one of claims 1 to 25, wherein the linker is a non-cleavable linker.

82. The antibody-drug conjugate of claim 81, wherein the linker comprises at least one spacer unit.

83. The antibody-drug conjugate of claim 81 or claim 82, wherein the spacer unit or linker comprises a polyethylene glycol (PEG) moiety.

84. The antibody-drug conjugate of claim 83, wherein the PEG moiety comprises - (PEG) and mis an integer from 1 to 10.

85. The antibody-drug conjugate of claim 84, wherein mis 2.

86. The antibody-drug conjugate of claim 81 or claim 82, wherein the spacer unit or linker comprises an alkyl moiety.

87. The antibody-drug conjugate of claim 86, wherein the alkyl moiety comprises -(CH2)s~ and nis an integer from 1 to 10.

88. The antibody-drug conjugate of claim 87, wherein nis 2.

89. The antibody-drug conjugate of claim 87, wherein nis 5.

90. The antibody-drug conjugate of claim 87, wherein nis 6.

91. The antibody-drug conjugate of any one of claims 81 to 90, wherein the spacer unit attaches to the antibody or antigen binding fragment via a maleimide (Mal) moiety (“Mal-spacer unit”).

92. The antibody-drug conjugate of claim 91, wherein the Mal-spacer unit is reactive with a cysteine residue on the antibody or antigen binding fragment.

93. The antibody-drug conjugate of claim 91 or claim 92, wherein the Mal-spacer unit is joined to the antibody or antigen binding fragment via a cysteine residue on the antibody or antigen binding fragment.

94. The antibody-drug conjugate of any one of claims 91 to 93, wherein the Mal- spacer unit comprises an alkyl moiety.

95. The antibody-drug conjugate of any one of claims 91 to 93, wherein the Mal- spacer unit comprises a PEG moiety.

96. The antibody-drug conjugate of any one of claims 91 to 95, wherein the linker or Mal-spacer unit comprises a maleimidocaproyl (MC).

97. The antibody-drug conjugate of claim 96, wherein the linker or Mal-spacer unit comprises a maleimidocaproyl (MC) and at least one additional spacer unit.

98. The antibody-drug conjugate of any one of claims 91 to 95, wherein the linker or Mal-spacer unit comprises MC-(PEG)2.

99. The antibody-drug conjugate of claim 98, wherein the linker or Mal-spacer unit comprises MC-(PEG). and at least one additional spacer unit.

100. The antibody-drug conjugate of any one of claims 91 to 95, wherein the linker or Mal-spacer unit comprises Mal-Hex.

101. The antibody-drug conjugate of claim 100, wherein the linker or Mal-spacer unit comprises Mal-Hex and at least one additional spacer unit.

102. The antibody-drug conjugate of any one of claims 91 to 95, wherein the linker or Mal-spacer unit comprises Mal-Et.

103. The antibody-drug conjugate of claim 102, wherein the linker or Mal-spacer unit comprises Mal-Et and at least one additional spacer unit.

104. The antibody-drug conjugate of any one of claims 91 to 95, wherein the linker or Mal-spacer unit comprises Mal-Et-O-Et.

105. The antibody-drug conjugate of claim 104, wherein the linker or Mal-spacer unit comprises Mal-Et-O-Et and at least one additional spacer unit.

106. The antibody-drug conjugate of any one of claims 91 to 105, wherein the Mal- spacer unit attaches the antibody or antigen binding fragment to the splicing modulator.

107. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing modulator comprises a splicing modulator of Formula (1): (II), or a pharmaceutically acceptable R'is chosen from absent, hydrogen, C+-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Ce heterocyclyl groups, -O-C(=0)- (C4-Cs alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; and R*, R, and R® are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R"7, -0-C(=0)-NRSR'8, C,-Cg alkyl groups, and -NR'SR18: R'® and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-0O-R'"; R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; and Ronn No” Ga "Or ey from Ry Ry Ry Ry , and R3, R4 RS R® R7, R? R'S, R' and R'7 are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR*R8, C4-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Ca-Cs heterocyclyl groups, wherein at least one of R® and R is hydrogen.

108. The antibody-drug conjugate of claim 107, wherein the linker covalently attaches structure of Formula (I-A): (11-A), or a pharmaceutically acceptable Ronn ~N._~ Rs % Rago Ren Qn from Ri Ry Ri Ri and her variables are as defined for Formula (lI). ns 1 to 108, wherein the splicing (IV), or a pharmaceutically R'is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, -O-C(=0)-(C1-Ce alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C+-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; and R*, R, and R® are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R"7, -0-C(=0)-NRSR'8, C,-Cg alkyl groups, and -NR'SR18: R'® and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-0-R'": and R17 is chosen from hydrogen, C1-Cs alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein RY, R%, R¢, RS, R%, R7, R8, RS, R18, and R'7 are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR$R8, C4-Cs cycloalkyl groups, C4-Cs alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Cs-Cs heterocyclyl groups, wherein at least one of R® and R? is hydrogen.

110. The antibody-drug conjugate of claim 109, wherein the linker covalently attaches of Formula (IV-A): (IV-A), or a pharmaceutically 111. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing VI), or a pharmaceutically acceptable R! and R® are each independently chosen from hydrogen, C1-Ce alkyl groups, C1-Ce alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C1-Ce alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Ce heterocyclyl groups, -O-C(=0)-(C+-Cs alkyl) groups, and -CDs3; R? is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R¢4, RS, and RE are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R” are each independently chosen from hydrogen, -O-R"", -O-C(=0)-R", -0-C(=0)-NRSR18, C4-Cg alkyl groups, -NR'R'¢, and a linker; Ris chosen from hydrogen, C1-Cs alkyl groups, -C(=0)-(C1-Cs alkyl) groups, and -CDg; R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'"; R17 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Csg heterocyclyl groups: and ais1,2,3,4,56,7,8, 9 0r10; wherein RY, R?, R4, R%, R%, R7, R8, R?, R'%, R'8, R'¢, and R'7 are each independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C1-Cs alkyl groups, -O-(C1-Ces alkyl) groups, -NR SR 8, C3-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Ce alkylalkoxy groups, benzyl groups, and Cs-Ce heterocyclyl groups; wherein at least one of R® and R7 is hydrogen; and wherein R' and R® cannot both be absent 112. The antibody-drug conjugate of claim 111, wherein the linker covalently attaches structure of Formula (VI-A): (VI-A), or a pharmaceutically 113. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing Formula (VIII): * a pharmaceutically acceptable salt thereof, R'is chosen from absent, hydrogen, C+-Ce alkyl groups, C+-Ce alkylalkoxy groups, C4-Cg alkylamino groups, C+-Cg alkylcarboxylic acid groups, C4-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Cs-Ceg heterocyclyl groups, -O-C(=0)- (C4-Cs alkyl) groups, and -CDa; R3 is chosen from hydrogen, C1-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R* is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, -O-C(=0)- (C1-Cs alkyl) groups, and C4-Cs alkyl groups: and R'is chosen from 3 to 10 membered carbocycles and 3 to 10 membered heterocycles, each of which is substituted with 0 to 3 R?, wherein each R? is independently chosen from halogens, C+-Ce alkyl groups, -O-(C1-Cg)alky! groups, C1-Ces alkylalkoxy groups, C+-Ce alkylhydroxy groups, -S(=O)w-(4 to 7 membered heterocycles), 4 to 7 membered carbocycles, and 4 to 7 membered heterocycles; R'5 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'""; and R17 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Csg heterocyclyl groups: wherein RY, R3, R4, R'°, R', R'8, and R'7 are each independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C+-Cs alkyl groups, -O-(C+-Cs alkyl) groups, -NR'5R8, C3-Cs cycloalkyl groups, C1-Ce alkylhydroxy groups, C1-Cs alkylalkoxy groups, benzyl groups, and Ci-Cg heterocyclyl groups; and wherein each R? is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, -NR'®R1®, C+-Ce alkyl groups, -(C=0)-(C1-Ce alkyl) groups, -(C=0)-(C4-Cs alkyl)-(Ca-C1o heterocyclyl) groups, -S(=0)w-(Ca-Cs heterocyclyl groups), and C+-Ce alkylcarboxylic acid groups, each of which is substituted with 0, 1, or 2 groups independently chosen from halogens, hydroxyl groups, -NR'*R¢, and C4-Ca alkyl groups; and wis 0, 1, or2.

114. The antibody-drug conjugate of claim 113, wherein the linker covalently attaches and L-D has a structure of Formula (VIII-A): ««...-A), or a pharmaceutically acceptable salt thereof.

115. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing modulator comprises a modulator of the SF3b complex.

116. The antibody-drug conjugate of claim 115, wherein the splicing modulator comprises a pladienolide or a pladienolide derivative.

117. The antibody-drug conjugate of claim 115 or claim 116, wherein the splicing modulator comprises pladienolide D or a pladienolide D derivative.

118. The antibody-drug conjugate of claim 117, wherein the pladienolide D or derivative comprises D2, D1, D4, D8, D10, D11 (E7107), D20, D21, D22, D12, or D25.

119. The antibody-drug conjugate of claim 117 or claim 118, wherein the pladienclide D or derivative comprises D2.

120. The antibody-drug conjugate of claim 117 or claim 118, wherein the pladienclide D or derivative comprises D1.

121. The antibody-drug conjugate of claim 117 or claim 118, wherein the pladienclide D or derivative is a zwitterionic pladienolide D or derivative.

122. The antibody-drug conjugate of claim 121, wherein the zwitterionic pladienolide D or derivative comprises D22 or D25.

123. The antibody-drug conjugate of claim 115 or claim 116, wherein the splicing modulator comprises pladienolide B or a pladienoclide B derivative.

124. The antibody-drug conjugate of claim 123, wherein the pladienoclide B or derivative comprises D9, D18, D19, or D13.

125. The antibody-drug conjugate of claim 115 or claim 116, wherein the splicing modulator comprises an aryl pladienolide.

126. The antibody-drug conjugate of claim 125, wherein the aryl pladienolide comprises D15, D14, D16, D17, D286, or D33.

127. The antibody-drug conjugate of claim 125 or claim 126, wherein the aryl pladienolide is a zwitterionic aryl pladienolide.

128. The antibody-drug conjugate of claim 127, wherein the zwitterionic aryl pladienolide comprises D33.

129. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing modulator comprises (D2).

130. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing modulator comprises 131. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing modulator comprises D4, D12, D15, D8, D9, D10, D13, D18, D19, D20, D21, D22, D25, or D33.

132. The antibody-drug conjugate of any one of claims 1 to 131, wherein p is from 1 to 10.

133. The antibody-drug conjugate of any one of claims 1 to 132, wherein p is from 2 to 8.

134. The antibody-drug conjugate of any one of claims 1 to 133, wherein p is from 4 to 8 135. The antibody-drug conjugate of any one of claims 1 to 134, wherein pis 4.

136. The antibody-drug conjugate of any one of claims 1 to 134, wherein pis 8.

137. An antibody-drug conjugate of Formula (1): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; Dis D2; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

138. The antibody-drug conjugate of claim 137, wherein the antibody or antigen binding fragment targets a HER2-expressing cell.

139. The antibody-drug conjugate of claim 138, wherein the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment.

140. The antibody-drug conjugate of claim 138 or claim 139, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR?2), and SEQ ID NO:3 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDRS3).

141. The antibody-drug conjugate of any one of claims 138 to 140, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:18, and a light chain variable region comprising an amino acid sequence of SEQ ID NOC:

20.

142. The antibody-drug conjugate of any one of claims 138 to 141, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

143. The antibody-drug conjugate of any one of claims 138 to 142, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

144. The antibody-drug conjugate of claim 137, wherein the antibody or antigen binding fragment targets a CD138-expressing cell.

145. The antibody-drug conjugate of claim 144, wherein the antibody or antigen binding fragment is an anti-CD138 antibody or antigen binding fragment.

146. The antibody-drug conjugate of claim 144 or claim 145, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR?2), and SEQ ID NO:9 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDR3).

147. The antibody-drug conjugate of any one of claims 144 to 146, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

22.

148. The antibody-drug conjugate of any one of claims 144 to 147, wherein the antibody or antigen binding fragment comprises a human IgG2a heavy chain constant region.

149. The antibody-drug conjugate of any one of claims 144 to 148, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

150. The antibody-drug conjugate of claim 137, wherein the antibody or antigen binding fragment targets an EPHA2-expressing cell.

151. The antibody-drug conjugate of claim 150, wherein the antibody or antigen binding fragment is an anti-EPHA2 antibody or antigen binding fragment.

152. The antibody-drug conjugate of claim 150 or claim 151, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDR3).

153. The antibody-drug conjugate of any one of claims 150 to 152, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

24.

154. The antibody-drug conjugate of any one of claims 150 to 153, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

155. The antibody-drug conjugate of any one of claims 150 to 154, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

156. An antibody-drug conjugate of Formula (1): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; Dis D1; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

157. The antibody-drug conjugate of claim 156, wherein the antibody or antigen binding fragment targets a HER2-expressing cell.

158. The antibody-drug conjugate of claim 157, wherein the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment.

159. The antibody-drug conjugate of claim 157 or claim 158, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDR3).

160. The antibody-drug conjugate of any one of claims 157 to 159, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:18, and a light chain variable region comprising an amino acid sequence of SEQ ID NOC:

20.

161. The antibody-drug conjugate of any one of claims 157 to 160, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

162. The antibody-drug conjugate of any one of claims 157 to 161, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

163. The antibody-drug conjugate of claim 156, wherein the antibody or antigen binding fragment targets a CD138-expressing cell.

164. The antibody-drug conjugate of claim 163, wherein the antibody or antigen binding fragment is an anti-CD138 antibody or antigen binding fragment.

165. The antibody-drug conjugate of claim 163 or claim 164, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR?2), and SEQ ID NO:9 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDR3).

166. The antibody-drug conjugate of any one of claims 163 to 165, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

22.

167. The antibody-drug conjugate of any one of claims 163 to 166, wherein the antibody or antigen binding fragment comprises a human IgG2a heavy chain constant region.

168. The antibody-drug conjugate of any one of claims 163 to 167, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

169. The antibody-drug conjugate of claim 156, wherein the antibody or antigen binding fragment targets an EPHA2-expressing cell.

170. The antibody-drug conjugate of claim 169, wherein the antibody or antigen binding fragment is an anti-EPHA2 antibody or antigen binding fragment.

171. The antibody-drug conjugate of claim 169 or claim 170, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR?2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO: 18 (LCDR3).

172. The antibody-drug conjugate of any one of claims 169 to 171, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

24.

173. The antibody-drug conjugate of any one of claims 169 to 172, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

174. The antibody-drug conjugate of any one of claims 169 to 173, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

175. An antibody-drug conjugate of Formula (1): Ab-(L-D), (I) wherein Ab is an anti-HER2 antibody or antigen binding fragment comprising three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDR3); Dis D2, D1, D4, D12, or D15; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

176. The antibody-drug conjugate of claim 175, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

20.

177. An antibody-drug conjugate of Formula (1): Ab-(L-D), (I) wherein Ab is an anti-CD138 antibody or antigen binding fragment comprising three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR2), and SEQ ID NO:9 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDRS3) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDR3): Dis D2, D1, D4, D12, or D15:; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

178. The antibody-drug conjugate of claim 177, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

22.

179. An antibody-drug conjugate of Formula (1): Ab-(L-D), (I) wherein Ab is an anti-EPHA2 antibody or antigen binding fragment comprising three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDR3); Dis D2, D1, D4, D12, or D15; L is a linker that covalently attaches Ab to D; and p is an integer from 1 to 15.

180. The antibody-drug conjugate of claim 179, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

24.

181. The antibody-drug conjugate of any one of claims 156 to 180, wherein the linker is a cleavable linker.

182. The antibody-drug conjugate of claim 181, wherein the cleavable linker comprises MC-Val-Cit-pABC.

183. The antibody-drug conjugate of claim 181, wherein the cleavable linker comprises MC-Val-Ala-pABC.

184. The antibody-drug conjugate of claim 181, wherein the cleavable linker comprises MC-Val-Ala-pAB.

185. The antibody-drug conjugate of any one of claims 156 to 180, wherein the linker is a non-cleavable linker.

186. The antibody-drug conjugate of claim 185, wherein the non-cleavable linker comprises Mal-Hex.

187. The antibody-drug conjugate of claim 185, wherein the non-cleavable linker comprises Mal-Et.

188. The antibody-drug conjugate of claim 185, wherein the non-cleavable linker comprises Mal-Et-O-Et.

189. The antibody-drug conjugate of any one of claims 156 to 188, wherein p is from 1to 10.

190. The antibody-drug conjugate of any one of claims 156 to 189, wherein p is from 21t0 8.

191. The antibody-drug conjugate of any one of claims 156 to 190, wherein p is from 4108.

192. The antibody-drug conjugate of any one of claims 156 to 191, wherein pis 4.

193. The antibody-drug conjugate of any one of claims 156 to 191, wherein pis 8.

194. A composition comprising multiple copies of the antibody-drug conjugate of any one of claims 1 to 193, wherein the average p of the antibody-drug conjugates in the composition is from about 3.5 to about 5.

5.

195. The composition of claim 194, wherein the average p of the antibody-drug conjugates in the composition is about 4.

196. A composition comprising multiple copies of the antibody-drug conjugate of any one of claims 1 to 193, wherein the average p of the antibody-drug conjugates in the composition is from about 7 to about 9.

197. The composition of claim 196, wherein the average p of the antibody-drug conjugates in the composition is about 8.

198. A method of treating a subject having or suspected of having a neoplastic disorder, comprising administering to the subject a therapeutically effective amount of the antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197.

199. The method of claim 198, wherein the neoplastic disorder is a hematological malignancy or a solid tumor.

200. The method of claim 198 or claim 199, wherein the neoplastic disorder is a hematological malignancy.

201. The method of claim 199 or claim 200, wherein the hematological malignancy is selected from acute myeloid leukemia and multiple myeloma.

202. The method of claim 198 or claim 199, wherein the neoplastic disorder is a solid tumor.

203. The method of claim 199 or claim 202, wherein the solid tumor is selected from breast cancer, gastric cancer, prostate cancer, ovarian cancer, lung cancer, uterine cancer, salivary duct carcinoma, melanoma, colon cancer, cervical cancer, pancreatic cancer, kidney cancer, colorectal cancer, and esophageal cancer.

204. The method of any one of claims 198 to 203, wherein treatment with the antibody-drug conjugate or composition induces bystander killing of neoplastic cells which do not express a target antigen but are adjacent to neoplastic cells which express a target antigen.

205. The method of any one of claims 198 to 204, wherein the subject has one or more neoplastic cells which express a target antigen.

206. The method of claim 205, wherein the target antigen is HER2.

207. The method of claim 206, wherein the one or more neoplastic cells are derived from a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer, uterine cancer, osteosarcoma, or salivary duct carcinoma.

208. The method of claim 207, wherein the lung cancer is lung adenocarcinoma and / or the uterine cancer is uterine serous endometrial carcinoma.

209. The method of any one of claims 206 to 208, wherein the subject is non- responsive or poorly responsive to treatment with (a) an anti-HER2 antibody when administered alone and / or (b) a splicing modulator when administered alone.

210. The method of any one of claims 206 to 209, wherein the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

211. The method of claim 205, wherein the target antigen is CD138.

212. The method of claim 211, wherein the one or more neoplastic cells are derived from a CD138-expressing multiple myeloma.

213. The method of claim 211 or claim 212, wherein the subject is non-responsive or poorly responsive to treatment with (a) an anti-CD138 antibody when administered alone and / or (b) a splicing modulator when administered alone.

214. The method of any one of claims 211 to 213, wherein the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

215. The method of claim 205, wherein the target antigen is EPHA2.

216. The method of claim 215, wherein the one or more neoplastic cells are derived from an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer.

217. The method of claim 215 or claim 216, wherein the subject is non-responsive or poorly responsive to treatment with (a) an anti-EPHA2 antibody when administered alone and / or (b) a splicing modulator when administered alone.

218. The method of any one of claims 215 to 217, wherein the subject is intolerant, non-responsive, or poorly responsive to treatment with a splicing modulator when administered alone.

219. A method of reducing or inhibiting growth of a tumor in a subject having or suspected of having a neoplastic disorder, comprising administering to the subject a therapeutically effective amount of the antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197.

220. The method of claim 219, wherein treatment with the antibody-drug conjugate or composition induces bystander killing of neoplastic tumor cells which do not express a target antigen but are adjacent to neoplastic tumor cells which express a target antigen.

221. The method of claim 219 or claim 220, wherein the tumor comprises one or more neoplastic cells which express a target antigen.

222. The method of claim 221, wherein the target antigen is HER2.

223. The method of claim 222, wherein the one or more neoplastic cells are derived from a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer, uterine cancer, osteosarcoma, or salivary duct carcinoma.

224. The method of claim 223, wherein the lung cancer is lung adenocarcinoma and / or the uterine cancer is uterine serous endometrial carcinoma.

225. The method of any one of claims 222 to 224, wherein the tumor is resistant or refractory to treatment with (a) an anti-HER2 antibody when administered alone and / or (b) a splicing modulator when administered alone.

226. The method of claim 221, wherein the target antigen is CD138.

227. The method of claim 226, wherein the one or more neoplastic cells are derived from a CD138-expressing multiple myeloma.

228. The method of claim 226 or claim 227, wherein the tumor is resistant or refractory to treatment with (a) an anti-CD138 antibody when administered alone and / or (b) a splicing modulator when administered alone.

229. The method of claim 221, wherein the target antigen is EPHA2.

230. The method of claim 229, wherein the one or more neoplastic cells are derived from an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer.

231. The method of claim 229 or claim 230, wherein the tumor is resistant or refractory to treatment with (a) an anti-EPHA2 antibody when administered alone and / or (b) a splicing modulator when administered alone.

232. A method of determining whether a subject having or suspected of having a neoplastic disorder will be responsive to treatment with the antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197, comprising providing a biological sample from the subject and contacting the biological sample with the antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197.

233. The method of claim 232, wherein the biological sample is a tumor sample.

234. The method of claim 233, wherein the tumor sample is a tumor biopsy or blood sample.

235. The method of claim 234, wherein the blood sample is selected from blood, a blood fraction, or a cell obtained from the blood or blood fraction.

236. The method of any one of claims 232 to 235, wherein the subject has one or more neoplastic cells which express a target antigen.

237. The method of claim 236, wherein the target antigen is HER2.

238. The method of claim 237, wherein the one or more neoplastic cells are derived from a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer, uterine cancer, osteosarcoma, or salivary duct carcinoma.

239. The method of claim 238, wherein the lung cancer is lung adenocarcinoma and / or the uterine cancer is uterine serous endometrial carcinoma.

240. The method of claim 236, wherein the target antigen is CD138.

241. The method of claim 240, wherein the one or more neoplastic cells are derived from a CD138-expressing multiple myeloma.

242. The method of claim 236, wherein the target antigen is EPHA2.

243. The method of claim 242, wherein the one or more neoplastic cells are derived from an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer.

244. An antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197 for use in the treatment of a neoplastic disorder.

245. The antibody-drug conjugate for use of claim 244, wherein the neoplastic disorder is characterized by having one or more neoplastic cells which express a target antigen.

246. The antibody-drug conjugate for use of claim 245, wherein the target antigen is HER2.

247. The antibody-drug conjugate for use of claim 246, wherein the neoplastic disorder is a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer, uterine cancer, osteosarcoma, or salivary duct carcinoma.

248. The antibody-drug conjugate of claim 247, wherein the lung cancer is lung adenocarcinoma and / or the uterine cancer is uterine serous endometrial carcinoma.

249. The antibody-drug conjugate for use of claim 245, wherein the target antigen is CD138.

250. The antibody-drug conjugate for use of claim 249, wherein the neoplastic disorder is a CD138-expressing multiple myeloma.

251. The antibody-drug conjugate for use of claim 245, wherein the target antigen is EPHA2.

252. The antibody-drug conjugate for use of claim 251, wherein the neoplastic disorder is an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer.

253. Use of an antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197 in the treatment of a neoplastic disorder.

254. The use of claim 253, wherein the neoplastic disorder is characterized by having one or more neoplastic cells which express a target antigen.

255. The use of claim 254, wherein the target antigen is HER2.

256. The use of claim 255, wherein the neoplastic disorder is a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer, uterine cancer, osteosarcoma, or salivary duct carcinoma.

257. The use of claim 256, wherein the lung cancer is lung adenocarcinoma and / or the uterine cancer is uterine serous endometrial carcinoma.

258. The use of claim 254, wherein the target antigen is CD138.

259. The use of claim 258, wherein the neoplastic disorder is a CD138-expressing multiple myeloma.

260. The use of claim 254, wherein the target antigen is EPHA2.

261. The use of claim 260, wherein the neoplastic disorder is an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer.

262. Use of an antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197 in a method of manufacturing a medicament for the treatment of a neoplastic disorder.

263. The use of claim 262, wherein the neoplastic disorder is characterized by having one or more neoplastic cells which express a target antigen.

264. The use of claim 263, wherein the target antigen is HER2.

265. The use of claim 264, wherein the neoplastic disorder is a HER2-expressing breast cancer, ovarian cancer, gastric cancer, lung cancer, uterine cancer, osteosarcoma, or salivary duct carcinoma.

266. The use of claim 265, wherein the lung cancer is lung adenocarcinoma and / or the uterine cancer is uterine serous endometrial carcinoma.

267. The use of claim 263, wherein the target antigen is CD138.

268. The use of claim 267, wherein the neoplastic disorder is a CD138-expressing multiple myeloma.

269. The use of claim 263, wherein the target antigen is EPHA2.

270. The use of claim 269, wherein the neoplastic disorder is an EPHA2-expressing breast cancer, prostate cancer, ovarian cancer, lung cancer, melanoma, colon cancer, or esophageal cancer.

271. A pharmaceutical composition comprising the antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197, and a pharmaceutically acceptable carrier.

272. A method of producing the antibody-drug conjugate of any one of claims 1 to 193, comprising reacting an antibody or antigen binding fragment with a linker joined to a splicing modulator under conditions that allow conjugation.

273. A compound of Formula (11): (Il), or a pharmaceutically acceptable R'is chosen from absent, hydrogen, C+-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Ce heterocyclyl groups, -O-C(=0)- (C4-Cs alkyl) groups, and -CDs; R2 is absent or a linker; R3 is chosen from hydrogen, C1-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C1-Cs alkyl) groups; and R¢, RS, and RE are each independently chosen from hydrogen, hydroxyl groups, - O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Ce alkyl groups; R® and R? are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R7, -0-C(=0)-NR'R18, C4-Cg alkyl groups, -NR'5R'¢, and a linker; R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'": R17 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Csg heterocyclyl groups: Ros nk Rs NE Repay Renn Ro~N._J I; from Ri Ry Ry Ry 32, R® R4 RS, RS, R7, RE R'™, R® and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR$R8, C4-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Ca-Cs heterocyclyl groups; wherein at least one of R® and R? is hydrogen; and wherein if R? is a linker, then neither R® or R” is a linker, and if R® or R is a linker, then R2 is absent. (V), or a pharmaceutically R'is chosen from absent, hydrogen, C+-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Cs-Ce heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDs; R2 is absent or a linker; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C+-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C4-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; and R¢4, RS, and RE are each independently chosen from hydrogen, hydroxyl groups, - O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Ce alkyl groups; R® and R? are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R7, -0-C(=0)-NR'R18, C4-Cg alkyl groups, -NR'5R'¢, and a linker; R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-0O-R'": and R'7 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Csg heterocyclyl groups: wherein R, R2, R?, R4, R%, R®, R7, R®, R'5, R'®, and R'? are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR'SR8, Ca-Cs cycloalkyl groups, C1-Ce alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Ca-Cs heterocyclyl groups; wherein at least one of R® and R7 is hydrogen; and wherein if R? is a linker, then neither R® or R7 is a linker, and if R® or R7 is a linker, then R2 is absent. (VII), or a pharmaceutically acceptable salt thereof, wherein: R' and R? are each independently chosen from absent, hydrogen, C+-Ce alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Ca-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, -O-C(=0)-(C+-Cs alkyl) groups, and -CDa; R2 is absent or a linker: R3 is chosen from hydrogen, C1-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, C3-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R*, R, and R® are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R"7, -0-C(=0)-NRSR'8, C4-Cg alkyl groups, -NR'*R'®, and a linker; R10 is chosen from hydrogen, C1-Ce alkyl groups, -C(=0)-(C1-Cs alkyl) groups, and -CDa; RS and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-0O-R'"; R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; and ais1,2,3,4,56,7,8, 9, or10; wherein RY, R2, R?, R4, R%, R®, R7, R¢, R®, R'%, R$, R'8, and R'” are each independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C1-Cs alkyl groups, -O-(C+-Ce alkyl) groups, -NR*R®, C5-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Ce alkylalkoxy groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein at least one of R® and R” is hydrogen; wherein if R2 is a linker, then neither R® or R7 is a linker, and if R® or R7 is a linker, then R2 is absent; and wherein R! and R® cannot both be absent. X): r a pharmaceutically acceptable salt thereof, wherein: hydrogen, C+-Ce alkyl groups, C1-Ce alkylalkoxy groups, C4-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Cs-Cs heterocyclyl groups, -O-C(=0)- (C1-Cs alkyl) groups, and -CDa; R2?is a linker; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Ce alkylcarboxylic acid groups, C1-Ce alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C1-Cs alkyl) groups; R* is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, -O-C(=0)- (C+-Cs alkyl) groups, and C1-Cs alkyl groups; R10 is chosen from 3 to 10 membered carbocycles and 3 to 10 membered heterocycles, each of which is substituted with 0 to 3 R?, wherein each R? is independently chosen from halogens, C-Cg alkyl groups, -O-(C4-Ce)alkyl groups, C4-Cs alkylalkoxy groups, Ci-Ce alkylhydroxy groups, -S(=O)w~(4 to 7 membered heterocycles), 4 to 7 membered carbocycles, and 4 to 7 membered heterocycles; R'® and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-0-R'"; and R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein R', R2, R%, R4, RR", R"8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C+-Ce alkyl groups, -O-(C+-Cs alkyl) groups, -NR'5R"8, C3-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Cs alkylalkoxy groups, benzyl groups, and Ci-Cg heterocyclyl groups; and wherein each Re is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, -NR'®R®, C1-Ce alkyl groups, -(C=0)-(C+-Ce alkyl) groups, -(C=0)-(C+-Cs alkyl)-( Ca-C10 heterocyclyl) groups, -S(=0)w-(C3-Cs heterocyclyl groups, and C1-Ce alkylcarboxylic acid groups, each of which is substituted with 0, 1, or 2 groups independently chosen from halogens, hydroxyl groups, -NR15R'8, and C4-Cs alkyl groups. compound of formula (D4), and pharmaceutically acceptable salts 278. A pharmaceutical composition comprising the compound of claim 277, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula (D8), and pharmaceutically acceptable 280. A pharmaceutical composition comprising the compound of claim 279, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula id pharmaceutically acceptable salts 282. A pharmaceutical composition comprising the compound of claim 281, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula and pharmaceutically acceptable salts 284. A pharmaceutical composition comprising the compound of claim 283, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. nd pharmaceutically 286. A pharmaceutical composition comprising the compound of claim 285, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula , and pharmaceutically acceptable salts 288. A pharmaceutical composition comprising the compound of claim 287, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula 19), and pharmaceutically acceptable 290. A pharmaceutical composition comprising the compound of claim 289, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula , and pharmaceutically acceptable salts 292. A pharmaceutical composition comprising the compound of claim 291, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula , and pharmaceutically acceptable salts 294. A pharmaceutical composition comprising the compound of claim 293, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula ind pharmaceutically acceptable salts 296. A pharmaceutical composition comprising the compound of claim 295, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. of formula , and pharmaceutically acceptable salts 298. A pharmaceutical composition comprising the compound of claim 297, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

299. A compound chosen from a compound of formula (D33), and pharmaceutically acceptable salts thereof.

300. A pharmaceutical composition comprising the compound of claim 299, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

301. A method of treating a subject having or suspected of having a neoplastic disorder, comprising administering to the subject a therapeutically effective amount of the compound or pharmaceutical composition of any one of claims 273 to 300.

302. A method of reducing or inhibiting growth of a tumor in a subject having or suspected of having a neoplastic disorder, comprising administering to the subject a therapeutically effective amount of the compound or pharmaceutical composition of any one of claims 273 to 300.

303. A method of inducing at least one neoantigen, comprising contacting a neoplastic cell with an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193, or the composition of any one of claims 194 to 197, thereby inducing production of at least one neoantigen.

304. The method of claim 303, wherein the at least one neoantigen comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

305. The method of claim 304, wherein the at least one neoantigen comprises an amino acid sequence of SEQ ID NO:

37.

306. The method of claim 304, wherein the at least one neoantigen comprises an amino acid sequence of SEQ ID NO:

39.

307. The method of claim 304, wherein the at least one neoantigen comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

308. The method of any one of claims 303 to 307, wherein the neoplastic cell is present in an in vitro cell culture.

309. The method of claim 308, wherein the neoplastic cell is obtained from a subject.

310. The method of any one of claims 303 to 307, wherein the neoplastic cell is present in a subject.

311. The method of any one of claims 303 to 310, wherein the neoplastic cell is derived from a hematological malignancy or a solid tumor.

312. The method of claim 311, wherein the hematological malignancy is selected from a B-cell malignancy, a leukemia, a lymphoma, and a myeloma.

313. The method of claim 311 or claim 312, wherein the hematological malignancy is selected from acute myeloid leukemia and multiple myeloma.

314. The method of claim 311, wherein the solid tumor is selected from breast cancer, gastric cancer, prostate cancer, ovarian cancer, lung cancer, uterine cancer, salivary duct carcinoma, melanoma, colon cancer, cervical cancer, pancreatic cancer, kidney cancer, colorectal cancer, and esophageal cancer.

315. A method of inducing at least one neoantigen and / or a T-cell response in a subject having or suspected of having a neoplastic disorder, comprising administering to the subject an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193, or the composition of any one of claims 194 to 197.

316. A method of treating a subject having or suspected of having a neoplastic disorder, comprising administering to the subject an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193, or the composition of any one of claims 194 to 197, wherein administration of the splicing modulator, antibody-drug conjugate, or composition induces at least one neoantigen and / or a T-cell response.

317. The method of claim 315 or claim 316, wherein the at least one neoantigen comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

318. The method of claim 317, wherein the at least one neoantigen comprises an amino acid sequence of SEQ ID NO:

37.

319. The method of claim 317, wherein the at least one neoantigen comprises an amino acid sequence of SEQ ID NO:

39.

320. The method of claim 317, wherein the at least one neoantigen comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

321. The method of any one of claims 315 to 320, wherein the administered amount of the splicing modulator, antibody-drug conjugate, or composition is reduced due to induction of at least one neoantigen and / or a T-cell response, as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition.

322. The method of any one of claims 315 to 321, wherein the administered amount of the splicing modulator, antibody-drug conjugate, or composition is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition.

323. The method of any one of claims 315 to 322, wherein the splicing modulator, antibody-drug conjugate, or composition is administered at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90% less frequently, as compared to a standard dosing regimen of the splicing modulator, antibody-drug conjugate, or composition.

324. The method of any one of claims 315 to 323, wherein the administered amount and / or dosage of the splicing modulator, antibody-drug conjugate, or composition results in lower systemic toxicity and / or improved tolerance.

325. The method of any one of claims 315 to 324, further comprising administering at least one additional therapy.

326. The method of claim 325, wherein the administered amount of the splicing modulator, antibody-drug conjugate, composition, and / or the at least one additional therapy is reduced due to induction of at least one neoantigen and / or a T-cell response, as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, composition, and / or the at least one additional therapy.

327. The method of claim 325 or claim 326, wherein the administered amount of the splicing modulator, antibody-drug conjugate, composition, and / or the at least one additional therapy is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the splicing modulator, antibody- drug conjugate, composition, and / or the at least one additional therapy.

328. The method of any one of claims 325 to 327, wherein the splicing modulator, antibody-drug conjugate, composition, and / or the at least one additional therapy is administered at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90% less frequently, as compared to a standard dosing regimen of the splicing modulator, antibody-drug conjugate, composition, and / or the at least one additional therapy.

329. The method of any one of claims 325 to 328, wherein the administered amount and / or dosage of the splicing modulator, antibody-drug conjugate, composition, and / or the at least one additional therapy results in lower systemic toxicity and / or improved tolerance.

330. The method of any one of claims 325 to 329, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is initiated before administration of the at least one additional therapy.

331. The method of any one of claims 325 to 329, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is initiated after administration of the at least one additional therapy.

332. The method of any one of claims 325 to 329, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is initiated concurrently with administration of the at least one additional therapy.

333. The method of any one of claims 315 to 332, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is repeated at least once after initial administration.

334. The method of claim 333, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced as compared to the amount used for initial administration.

335. The method of claim 333 or claim 334, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition.

336. The method of any one of claims 333 to 335, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition.

337. The method of any one of claims 325 to 336, wherein administration of the at least one additional therapy is repeated at least once after initial administration.

338. The method of claim 337, wherein the amount of the at least one additional therapy used for repeated administration is reduced as compared to the amount used for initial administration.

339. The method of claim 337 or claim 338, wherein the amount of the at least one additional therapy used for repeated administration is reduced as compared to a standard dosage of the at least one additional therapy.

340. The method of any one of claims 337 to 339, wherein the amount of the at least one additional therapy used for repeated administration is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the at least one additional therapy.

341. The method of any one of claims 337 to 340, wherein repeated administration of the splicing modulator, antibody-drug conjugate, or composition is concurrent with repeated administration of the at least one additional therapy.

342. The method of any one of claims 337 to 340, wherein repeated administration of the splicing modulator, antibody-drug conjugate, or composition is sequential or staggered with repeated administration of the at least one additional therapy.

343. The method of any one of claims 325 to 342, wherein the at least one additional therapy comprises administering a checkpoint inhibitor.

344. The method of claim 343, wherein the subject is intolerant, non-responsive, or poorly responsive to the checkpoint inhibitor when administered alone.

345. The method of claim 343 or claim 344, wherein the checkpoint inhibitor targets CTLA4, PD1, PDL1, OX40, CD40, GITR, LAG3, TIM3, and / or KIR.

346. The method of any one of claims 343 to 345, wherein the checkpoint inhibitor targets CTLA4, OX40, CD40, and / or GITR.

347. The method of any one of claims 343 to 346, wherein the checkpoint inhibitor comprises a cytotoxic T-lymphocyte-associated antigen 4 pathway (CTLA4) inhibitor.

348. The method of claim 347, wherein the CTLA4 inhibitor is an anti-CTLA4 antibody.

349. The method of claim 348, wherein the anti-CTLA4 antibody is ipilimumab.

350. The method of any one of claims 343 to 346, wherein the checkpoint inhibitor comprises a programmed death-1 pathway (PD1) inhibitor.

351. The method of claim 350, wherein the PD1 inhibitor is an anti-PD1 antibody.

352. The method of claim 351, wherein the anti-PD1 antibody is nivolumab.

353. The method of claim 350, wherein the PD1 inhibitor is an anti-PDL1 antibody.

354. The method of claim 353, wherein the anti-PDL1 antibody is atezolizumab.

355. The method of any one of claims 343 to 346, wherein the checkpoint inhibitor comprises a CTLA4 inhibitor and a PD1 inhibitor.

356. The method of claim 355, wherein the CTLA4 inhibitor is an anti-CTLA4 antibody.

357. The method of claim 356, wherein the anti-CTLA4 antibody is ipilimumab.

358. The method of claim 355, wherein the PD1 inhibitor is an anti-PD1 antibody.

359. The method of claim 358, wherein the anti-PD1 antibody is nivolumab.

360. The method of claim 355, wherein the PD1 inhibitor is an anti-PDL1 antibody.

361. The method of claim 360, wherein the anti-PDL1 antibody is atezolizumab.

362. The method of any one of claims 325 to 342, wherein the at least one additional therapy comprises administering a neoantigen vaccine.

363. The method of claim 362, wherein the splicing modulator, antibody-drug conjugate, or composition is administered before administration of the neoantigen vaccine.

364. The method of claim 362, wherein the splicing modulator, antibody-drug conjugate, or composition is administered after administration of the neoantigen vaccine.

365. The method of claim 362, wherein the splicing modulator, antibody-drug conjugate, or composition is administered concurrently with administration of the neoantigen vaccine.

366. The method of any one of claims 362 to 365, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is repeated at least once after initial administration.

367. The method of claim 366, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced as compared to the amount used for initial administration.

368. The method of any one of claims 362 to 367, wherein the neoantigen vaccine comprises at least one neoantigen peptide.

369. The method of claim 368, wherein the at least one neoantigen peptide ranges from about 10 to about 50 or about 10 to about 35 amino acids in length.

370. The method of claim 368 or claim 369, wherein the at least one neoantigen peptide ranges from about 15 to about 25 amino acids in length.

371. The method of any one of claims 368 to 370, wherein the at least one neoantigen peptide comprises one or more than one neoantigen sequence.

372. The method of claim 371, wherein the neoantigen sequence is a neoantigen sequence specific to the subject.

373. The method of claim 371, wherein the neoantigen sequence is a universal neoantigen sequence.

374. The method of any one of claims 371 to 373, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

375. The method of claim 374, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

37.

376. The method of claim 374, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

39.

377. The method of claim 374, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

378. The method of any one of claims 371 to 373, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

379. The method of claim 378, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

66.

380. The method of claim 378, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

381. The method of any one of claims 374 to 380, wherein the neoantigen sequence and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

382. The method of any one of claims 374 to 381, wherein the neoantigen sequence and / or antigenic portion is a personalized neoantigen vaccine for the subject.

383. The method of claim 382, wherein the neoantigen sequence and / or antigenic portion has been identified by sequencing at least one neoantigen induced in the subject by administering an effective amount of the splicing modulator, antibody-drug conjugate, or composition.

384. The method of claim 382 or claim 383, wherein the neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in the subject.

385. The method of any one of claims 374 to 381, wherein the neoantigen sequence and / or antigenic portion is a universal neoantigen vaccine.

386. The method of claim 385, wherein the neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 45% of subjects in a population of subjects suffering from the neoplastic disorder.

387. The method of claim 385 or claim 386, wherein the neoantigen sequence and / or antigenic portion is capable of eliciting a T-cell response against a tumor present in at least 1%, at least 5%, or at least 10% of a population of subjects suffering from the neoplastic disorder.

388. The method of any one of claims 385 to 387, wherein the at least one neoantigen peptide comprises a neoantigen sequence induced by contacting a neoplastic cell with an effective amount of the splicing modulator, antibody-drug conjugate, or composition.

389. The method of any one of claims 362 to 367, wherein the neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable carrier.

390. The method of claim 389, wherein the at least one neoantigen peptide is linked to the pharmaceutically acceptable carrier.

391. The method of claim 389 or claim 390, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

392. The method of any one of claims 389 to 391, wherein the neoantigen peptide and the pharmaceutically acceptable carrier are covalently attached via a linker.

393. The method of any one of claims 389 to 391, wherein the neoantigen peptide and the pharmaceutically acceptable carrier are expressed as a fusion protein.

394. The method of any one of claims 362 to 367, wherein the neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable diluent.

395. The method of any one of claims 362 to 367, wherein the neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable adjuvant.

396. The method of claim 388, wherein the neoplastic cell is present in an in vitro cell culture.

397. The method of claim 396, wherein the neoplastic cell is obtained from the subject.

398. The method of claim 388, wherein the neoplastic cell is present in the subject.

399. The method of any one of claims 362 to 367, wherein the neoantigen vaccine comprises at least one neoantigen mRNA.

400. The method of claim 399, wherein the at least one necantigen mRNA encodes one or more than one neoantigen sequence.

401. The method of claim 400, wherein the necantigen sequence is a necantigen sequence specific to the subject.

402. The method of claim 400, wherein the necantigen sequence is a universal neoantigen sequence.

403. The method of any one of claims 400 to 402, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

404. The method of claim 403, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

37.

405. The method of claim 403, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

39.

406. The method of claim 403, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

407. The method of any one of claims 400 to 402, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

408. The method of claim 407, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

66.

409. The method of claim 407, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

410. The method of any one of claims 403 to 409, wherein the neoantigen sequence and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

411. The method of any one of claims 403 to 410, wherein the neoantigen sequence and / or antigenic portion is a personalized neoantigen vaccine for the subject.

412. The method of claim 411, wherein the necantigen sequence and / or antigenic portion has been identified by sequencing at least one neoantigen induced in the subject by administering an effective amount of the splicing modulator, antibody-drug conjugate, or composition.

413. The method of claim 411 or claim 412, wherein the neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in the subject.

414. The method of any one of claims 403 to 410, wherein the neoantigen sequence and / or antigenic portion is a universal neoantigen vaccine. 415, The method of claim 414, wherein the neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 45% of subjects in a population of subjects suffering from the neoplastic disorder.

416. The method of claim 414 or claim 415, wherein the neoantigen sequence and / or antigenic portion is capable of eliciting a T-cell response against a tumor present in at least 1%, at least 5%, or at least 10% of a population of subjects suffering from the neoplastic disorder.

417. The method of any one of claims 414 to 416, wherein the at least one neoantigen mRNA encodes a neoantigen sequence induced by contacting a neoplastic cell with an effective amount of the splicing modulator, antibody-drug conjugate, or composition.

418. The method of any one of claims 362 to 367, wherein the neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable carrier.

419. The method of claim 418, wherein the at least one necantigen mRNA is linked to the pharmaceutically acceptable carrier.

420. The method of claim 418 or claim 419, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

421. The method of any one of claims 362 to 367, wherein the neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable diluent.

422. The method of any one of claims 362 to 367, wherein the neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable adjuvant.

423. The method of any one of claims 399 to 422, wherein the neoantigen mRNA is encapsulated by an encapsulating agent.

424. The method of claim 423, wherein the encapsulating agent is a liposome. 425, The method of claim 423, wherein the encapsulating agent is a nanoparticle.

426. The method of claim 417, wherein the neoplastic cell is present in an in vitro cell culture.

427. The method of claim 426, wherein the neoplastic cell is obtained from the subject.

428. The method of claim 417, wherein the neoplastic cell is present in the subject.

429. The method of any one of claims 325 to 342, wherein the at least one additional therapy comprises administering a cytokine or cytokine analog.

430. The method of claim 429, wherein the subject is intolerant, non-responsive, or poorly responsive to the cytokine or cytokine analog when administered alone.

431. The method of claim 429 or claim 430, wherein the cytokine or cytokine analog comprises a T-cell enhancer.

432. The method of any one of claims 429 to 431, wherein the cytokine or cytokine analog comprises IL-2, IL-10, IL-12, IL-15, IFNy, and / or TNFa.

433. The method of any one of claims 325 to 342, wherein the at least one additional therapy comprises administering engineered tumor-targeting T-cells.

434. The method of any one of claims 315 to 433, further comprising detecting one or more neoantigens and / or a T-cell response in the subject after administration of the splicing modulator, antibody-drug conjugate, or composition. 435, The method of claim 434, further comprising continuing administration of the splicing modulator, antibody-drug conjugate, or composition if one or more neoantigens and / or a T-cell response is detected.

436. The method of claim 434 or claim 435, further comprising continuing administration of the splicing modulator, antibody-drug conjugate, or composition less frequently and / or at a reduced dosage if one or more neoantigens and / or a T-cell response is detected.

437. The method of any one of claims 434 to 436, wherein detecting one or more neoantigens and / or a T-cell response in the subject indicates efficacy of treatment with the splicing modulator, antibody-drug conjugate, or composition.

438. The method of any one of claims 315 to 437, wherein the subject has a non- synonymous mutational burden of about 150 mutations or less.

439. The method of any one of claims 315 to 438, wherein the subject has a non- synonymous mutational burden of about 100 mutations or less.

440. The method of any one of claims 315 to 439, wherein the subject has a non- synonymous mutational burden of about 50 mutations or less.

441. The method of any one of claims 315 to 440, wherein the neoplastic disorder is a hematological malignancy or a solid tumor.

442. The method of claim 441, wherein the hematological malignancy is selected from a B-cell malignancy, a leukemia, a lymphoma, and a myeloma.

443. The method of claim 441 or claim 442, wherein the hematological malignancy is selected from acute myeloid leukemia and multiple myeloma.

444. The method of claim 441, wherein the solid tumor is selected from breast cancer, gastric cancer, prostate cancer, ovarian cancer, lung cancer, uterine cancer, salivary duct carcinoma, melanoma, colon cancer, cervical cancer, pancreatic cancer, kidney cancer, colorectal cancer, and esophageal cancer.

445. A method of treating a subject having or suspected of having a neoplastic disorder, comprising: (a) administering to the subject an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193, or the composition of any one of claims 194 to 197, wherein administration of the splicing modulator, antibody- drug conjugate, or composition induces at least one neoantigen and / or a T-cell response; (b) detecting one or more neoantigens and / or a T-cell response in the subject after administration of the splicing modulator, antibody-drug conjugate, or composition; and (©) continuing administration of the splicing modulator, antibody-drug conjugate, or composition if one or more neoantigens and / or a T-cell response is detected.

446. The method of claim 445, wherein detecting one or more neoantigens and / or a T-cell response in the subject indicates efficacy of treatment with the splicing modulator, antibody-drug conjugate, or composition.

447. The method of claim 445 or claim 446, wherein the one or more neoantigens comprise an amino acid sequence of any one of SEQ ID NOs: 37-65.

448. The method of claim 447, wherein the one or more neoantigens comprise an amino acid sequence of SEQ ID NO:

37.

449. The method of claim 447, wherein the one or more neoantigens comprise an amino acid sequence of SEQ ID NO:

39.

450. The method of claim 447, wherein the one or more neoantigens comprise an amino acid sequence of any one of SEQ ID NOs: 46-49. 451, A method of treating a subject having or suspected of having a neoplastic disorder, comprising administering to the subject an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193, or the composition of any one of claims 194 to 197; and at least one additional therapy. 452, The method of claim 451, wherein the at least one additional therapy comprises at least one, at least two, at least three, at least four, or at least five additional therapies.

453. The method of claim 451 or claim 452, wherein administration of the splicing modulator, antibody-drug conjugate, or composition induces at least one neoantigen and / or a T-cell response. 454, The method of any one of claims 451 to 453, wherein the administered amount of the splicing modulator, antibody-drug conjugate, or composition and / or the at least one additional therapy is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition and / or the at least one additional therapy.

455. The method of any one of claims 451 to 454, wherein the splicing modulator, antibody-drug conjugate, or composition and / or the at least one additional therapy is administered at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 80% less frequently, as compared to a standard dosing regimen of the splicing modulator, antibody-drug conjugate, or composition and / or the at least one additional therapy.

456. The method of any one of claims 451 to 455, wherein the administered amount and / or dosage of the splicing modulator, antibody-drug conjugate, or composition and / or the at least one additional therapy results in lower systemic toxicity and / or improved tolerance.

457. The method of any one of claims 451 to 456, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is initiated before administration of the at least one additional therapy.

458. The method of any one of claims 451 to 456, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is initiated after administration of the at least one additional therapy.

459. The method of any one of claims 451 to 456, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is initiated concurrently with administration of the at least one additional therapy.

460. The method of any one of claims 451 to 460, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is repeated at least once after initial administration.

461. The method of claim 460, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced as compared to the amount used for initial administration.

462. The method of claim 460 or claim 461, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition.

463. The method of any one of claims 460 to 462, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition.

464. The method of any one of claims 451 to 463, wherein administration of the at least one additional therapy is repeated at least once after initial administration.

465. The method of claim 464, wherein the amount of the at least one additional therapy used for repeated administration is reduced as compared to the amount used for initial administration.

466. The method of claim 464 or claim 465, wherein the amount of the at least one additional therapy used for repeated administration is reduced as compared to a standard dosage of the at least one additional therapy.

467. The method of any one of claims 464 to 466, wherein the amount of the at least one additional therapy used for repeated administration is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the at least one additional therapy.

468. The method of any one of claims 464 to 467, wherein repeated administration of the splicing modulator, antibody-drug conjugate, or composition is concurrent with repeated administration of the at least one additional therapy.

469. The method of any one of claims 464 to 467, wherein repeated administration of the splicing modulator, antibody-drug conjugate, or composition is sequential or staggered with repeated administration of the at least one additional therapy.

470. The method of any one of claims 451 to 469, wherein the at least one additional therapy comprises administering a checkpoint inhibitor.

471. The method of claim 470, wherein the subject is intolerant, non-responsive, or poorly responsive to the checkpoint inhibitor when administered alone.

472. The method of claim 470 or claim 471, wherein the checkpoint inhibitor targets CTLA4, PD1, PDL1, OX40, CD40, GITR, LAG3, TIM3, and / or KIR.

473. The method of any one of claims 470 to 472, wherein the checkpoint inhibitor targets CTLA4, OX40, CD40, and / or GITR.

474. The method of any one of claims 470 to 473, wherein the checkpoint inhibitor comprises a cytotoxic T-lymphocyte-associated antigen 4 pathway (CTLA4) inhibitor.

475. The method of claim 474, wherein the CTLA4 inhibitor is an anti-CTLA4 antibody.

476. The method of claim 475, wherein the anti-CTLA4 antibody is ipilimumab.

477. The method of any one of claims 470 to 473, wherein the checkpoint inhibitor comprises a programmed death-1 pathway (PD1) inhibitor.

478. The method of claim 477, wherein the PD1 inhibitor is an anti-PD1 antibody.

479. The method of claim 478, wherein the anti-PD1 antibody is nivolumab.

480. The method of claim 477, wherein the PD1 inhibitor is an anti-PDL1 antibody.

481. The method of claim 480, wherein the anti-PDL1 antibody is atezolizumab.

482. The method of any one of claims 470 to 473, wherein the checkpoint inhibitor comprises a CTLA4 inhibitor and a PD1 inhibitor.

483. The method of claim 482, wherein the CTLA4 inhibitor is an anti-CTLA4 antibody.

484. The method of claim 483, wherein the anti-CTLA4 antibody is ipilimumab. 485, The method of claim 482, wherein the PD1 inhibitor is an anti-PD1 antibody.

486. The method of claim 485, wherein the anti-PD1 antibody is nivolumab.

487. The method of claim 482, wherein the PD1 inhibitor is an anti-PDL1 antibody.

488. The method of claim 487, wherein the anti-PDL1 antibody is atezolizumab.

489. The method of any one of claims 451 to 469, wherein the at least one additional therapy comprises administering a neoantigen vaccine.

490. The method of claim 489, wherein the splicing modulator, antibody-drug conjugate, or composition is administered before administration of the neoantigen vaccine.

491. The method of claim 489, wherein the splicing modulator, antibody-drug conjugate, or composition is administered after administration of the neoantigen vaccine.

492. The method of claim 489, wherein the splicing modulator, antibody-drug conjugate, or composition is administered concurrently with administration of the neoantigen vaccine.

493. The method of any one of claims 489 to 492, wherein administration of the splicing modulator, antibody-drug conjugate, or composition is repeated at least once after initial administration.

494. The method of claim 493, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced as compared to the amount used for initial administration.

495. The method of any one of claims 489 to 494, wherein the neoantigen vaccine comprises at least one neoantigen peptide.

496. The method of claim 495, wherein the at least one neoantigen peptide ranges from about 10 to about 50 or about 10 to about 35 amino acids in length.

497. The method of claim 495 or claim 496, wherein the at least one neoantigen peptide ranges from about 15 to about 25 amino acids in length.

498. The method of any one of claims 495 to 497, wherein the at least one neoantigen peptide comprises one or more than one neoantigen sequence.

499. The method of claim 498, wherein the necantigen sequence is a necantigen sequence specific to the subject.

500. The method of claim 498, wherein the neoantigen sequence is a universal neoantigen sequence.

501. The method of any one of claims 498 to 500, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

502. The method of claim 501, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

37.

503. The method of claim 501, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

39.

504. The method of claim 501, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

505. The method of any one of claims 498 to 500, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

506. The method of claim 505, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

66.

507. The method of claim 505, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

508. The method of any one of claims 501 to 507, wherein the neoantigen sequence and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

508. The method of any one of claims 501 to 508, wherein the neoantigen sequence and / or antigenic portion is a personalized neoantigen vaccine for the subject.

510. The method of claim 509, wherein the neoantigen sequence and / or antigenic portion has been identified by sequencing at least one neoantigen induced in the subject by administering an effective amount of the splicing modulator, antibody-drug conjugate, or composition.

511. The method of claim 509 or claim 510, wherein the neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in the subject.

512. The method of any one of claims 501 to 508, wherein the neoantigen sequence and / or antigenic portion is a universal neoantigen vaccine.

513. The method of claim 512, wherein the neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 45% of subjects in a population of subjects suffering from the neoplastic disorder.

514. The method of claim 512 or claim 513, wherein the neoantigen sequence and / or antigenic portion is capable of eliciting a T-cell response against a tumor present in at least 1%, at least 5%, or at least 10% of a population of subjects suffering from the neoplastic disorder.

515. The method of any one of claims 512 to 514, wherein the at least one neoantigen peptide comprises a neoantigen sequence induced by contacting a neoplastic cell with an effective amount of the splicing modulator, antibody-drug conjugate, or composition.

516. The method of any one of claims 489 to 494, wherein the neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable carrier.

517. The method of claim 516, wherein the at least one neoantigen peptide is linked to the pharmaceutically acceptable carrier.

518. The method of claim 516 or claim 517, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

519. The method of any one of claims 516 to 518, wherein the neoantigen peptide and the pharmaceutically acceptable carrier are covalently attached via a linker.

520. The method of any one of claims 516 to 518, wherein the neoantigen peptide and the pharmaceutically acceptable carrier are expressed as a fusion protein.

521. The method of any one of claims 489 to 494, wherein the neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable diluent.

522. The method of any one of claims 489 to 494, wherein the neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable adjuvant.

523. The method of claim 515, wherein the neoplastic cell is present in an in vitro cell culture.

524. The method of claim 523, wherein the neoplastic cell is obtained from the subject.

525. The method of claim 515, wherein the neoplastic cell is present in the subject.

526. The method of any one of claims 489 to 494, wherein the neoantigen vaccine comprises at least one neoantigen mRNA.

527. The method of claim 526, wherein the at least one neoantigen mRNA encodes one or more than one neoantigen sequence.

528. The method of claim 527, wherein the neoantigen sequence is a neoantigen sequence specific to the subject.

529. The method of claim 527, wherein the neoantigen sequence is a universal neoantigen sequence.

530. The method of any one of claims 527 to 529, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

531. The method of claim 530, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

37.

532. The method of claim 530, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

39.

533. The method of claim 530, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

534. The method of any one of claims 527 to 529, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

535. The method of claim 534, wherein the neoantigen sequence comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

66.

536. The method of claim 534, wherein the neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

537. The method of any one of claims 530 to 536, wherein the neoantigen sequence and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

538. The method of any one of claims 530 to 537, wherein the neoantigen sequence and / or antigenic portion is a personalized neoantigen vaccine for the subject.

539. The method of claim 538, wherein the neoantigen sequence and / or antigenic portion has been identified by sequencing at least one neoantigen induced in the subject by administering an effective amount of the splicing modulator, antibody-drug conjugate, or composition.

540. The method of claim 538 or claim 539, wherein the neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in the subject.

541. The method of any one of claims 530 to 537, wherein the neoantigen sequence and / or antigenic portion is a universal neoantigen vaccine.

542. The method of claim 541, wherein the neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 45% of subjects in a population of subjects suffering from the neoplastic disorder.

543. The method of claim 541 or claim 542, wherein the neoantigen sequence and / or antigenic portion is capable of eliciting a T-cell response against a tumor present in at least 1%, at least 5%, or at least 10% of a population of subjects suffering from the neoplastic disorder.

544. The method of any one of claims 541 to 543, wherein the at least one neoantigen MRNA encodes a neoantigen sequence induced by contacting a neoplastic cell with an effective amount of the splicing modulator, antibody-drug conjugate, or composition.

545. The method of any one of claims 489 to 494, wherein the neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable carrier.

546. The method of claim 545, wherein the at least one neoantigen mRNA is linked to the pharmaceutically acceptable carrier.

547. The method of claim 545 or claim 546, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

548. The method of any one of claims 489 to 494, wherein the neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable diluent.

549. The method of any one of claims 489 to 494, wherein the neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable adjuvant.

550. The method of any one of claims 526 to 549, wherein the neoantigen mRNA is encapsulated by an encapsulating agent.

551. The method of claim 550, wherein the encapsulating agent is a liposome.

552. The method of claim 550, wherein the encapsulating agent is a nanoparticle.

553. The method of claim 544, wherein the neoplastic cell is present in an in vitro cell culture.

554. The method of claim 553, wherein the neoplastic cell is obtained from the subject.

555. The method of claim 544, wherein the neoplastic cell is present in the subject.

556. The method of any one of claims 451 to 469, wherein the at least one additional therapy comprises administering a cytokine or cytokine analog.

557. The method of claim 556, wherein the subject is intolerant, non-responsive, or poorly responsive to the cytokine or cytokine analog when administered alone.

558. The method of claim 556 or claim 557, wherein the cytokine or cytokine analog comprises a T-cell enhancer.

559. The method of any one of claims 556 to 558, wherein the cytokine or cytokine analog comprises IL-2, IL-10, IL-12, IL-15, IFNy, and / or TNFa.

560. The method of any one of claims 451 to 469, wherein the at least one additional therapy comprises administering engineered tumor-targeting T-cells.

561. The method of any one of claims 451 to 560, wherein the subject has a non- synonymous mutational burden of about 150 mutations or less.

562. The method of any one of claims 451 to 561, wherein the subject has a non- synonymous mutational burden of about 100 mutations or less.

563. The method of any one of claims 451 to 562, wherein the subject has a non- synonymous mutational burden of about 50 mutations or less.

564. The method of any one of claims 451 to 563, wherein the neoplastic disorder is a hematological malignancy or a solid tumor.

565. The method of claim 564, wherein the hematological malignancy is selected from a B-cell malignancy, a leukemia, a lymphoma, and a myeloma.

566. The method of claim 564 or claim 565, wherein the hematological malignancy is selected from acute myeloid leukemia and multiple myeloma.

567. The method of claim 564, wherein the solid tumor is selected from breast cancer, gastric cancer, prostate cancer, ovarian cancer, lung cancer, uterine cancer, salivary duct carcinoma, melanoma, colon cancer, cervical cancer, pancreatic cancer, kidney cancer, colorectal cancer, and esophageal cancer.

568. A method of identifying at least one neoantigen, comprising: (a) contacting a neoplastic cell with an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193, or the composition of any one of claims 194 to 197; (b) detecting at least one alternatively-spliced mRNA transcript after contacting the neoplastic cell with the splicing modulator, antibody-drug conjugate, or composition; (©) predicting translation of the at least one alternatively-spliced mRNA transcript into at least one peptide; and (d) comparing the at least one peptide to a reference proteome, wherein at least one neoantigen is identified if the at least one peptide does not match any peptides in the reference proteome.

569. The method of claim 568, wherein detecting at least one alternatively-spliced mRNA transcript comprises RNAseq.

570. The method of claim 568 or claim 569, wherein predicting translation of the at least one alternatively-spliced mRNA transcript comprises quantifying the change in percent spliced in (dPSI) value for the at least one transcript.

571. The method of any one of claims 568 to 570, wherein predicting translation of the at least one alternatively-spliced mRNA transcript comprises RiboSeq and / or ribosomal profiling.

572. The method of any one of claims 568 to 571, wherein the method further comprises evaluating the at least one peptide for predicted major histocompatibility complex (MHC) binding.

573. The method of claim 572, wherein predicted MHC binding is determined by measuring raw affinity predicted binding strength of the at least one peptide.

574. The method of claim 573, wherein a raw affinity predicted binding strength of about 500 nM or higher indicates MHC binding.

575. The method of claim 572, wherein predicted MHC binding is determined by identifying a distribution of predicted binding strengths for a series of random peptides; and comparing predicted binding strength of the at least one peptide to the distribution.

576. The method of claim 575, wherein a predicted binding strength in the top 2.0% of the distribution indicates weak MHC binding.

577. The method of claim 575, wherein a predicted binding strength in the top 0.5% of the distribution indicates strong MHC binding.

578. The method of any one of claims 568 to 577, wherein the neoplastic cell is present in an in vitro cell culture.

579. The method of claim 578, wherein the neoplastic cell is obtained from the subject.

580. The method of any one of claims 568 to 577, wherein the neoplastic cell is present in the subject.

581. The method of any one of claims 568 to 580, further comprising contacting one or more additional neoplastic cells to identify at least one universal neoantigen.

582. A method of identifying at least one neoantigen, comprising: (a) contacting a neoplastic cell with an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193, or the composition of any one of claims 194 to 197; (b) detecting at least one peptide comprising a potential neoantigen sequence after contacting the neoplastic cell with the splicing modulator, antibody-drug conjugate, or composition; and © comparing the at least one peptide to a reference proteome, wherein at least one neoantigen is identified if the at least one peptide does not match any peptides in the reference proteome.

583. The method of claim 582, wherein the method further comprises evaluating the at least one peptide for predicted major histocompatibility complex (MHC) binding.

584. The method of claim 583, wherein predicted MHC binding is determined by measuring raw affinity predicted binding strength of the at least one peptide.

585. The method of claim 584, wherein a raw affinity predicted binding strength of about 500 nM or higher indicates MHC binding.

586. The method of claim 583, wherein predicted MHC binding is determined by identifying a distribution of predicted binding strengths for a series of random peptides; and comparing predicted binding strength of the at least one peptide to the distribution.

587. The method of claim 586, wherein a predicted binding strength in the top 2.0% of the distribution indicates weak MHC binding.

588. The method of claim 586, wherein a predicted binding strength in the top 0.5% of the distribution indicates strong MHC binding.

589. The method of any one of claims 582 to 588, wherein the neoplastic cell is present in an in vitro cell culture.

590. The method of claim 589, wherein the neoplastic cell is obtained from the subject.

591. The method of any one of claims 582 to 588, wherein the neoplastic cell is present in the subject.

592. The method of any one of claims 582 to 591, further comprising contacting one or more additional neoplastic cells to identify at least one universal neoantigen.

593. A method of making a neoantigen vaccine, comprising: (a) identifying at least one neoantigen using the method of any one of claims 568 to 592; and (b) formulating the at least one neoantigen together with a pharmaceutically acceptable carrier, diluent, or adjuvant.

594. The method of claim 593, wherein the at least one neoantigen comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

595. The method of claim 594, wherein the at least one neoantigen comprises an amino acid sequence of SEQ ID NO:

37.

596. The method of claim 594, wherein the at least one neoantigen comprises an amino acid sequence of SEQ ID NO:

39.

597. The method of claim 594, wherein the at least one neoantigen comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

598. The method of claim 593, wherein the at least one neoantigen comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

599. The method of claim 598, wherein the at least one neoantigen comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

66.

600. The method of claim 598, wherein the at least one neoantigen comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

601. The method of any one of claims 593 to 600, wherein the at least one neoantigen and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

602. The method of any one of claims 593 to 601, wherein the at least one neoantigen and / or antigenic portion is linked to the pharmaceutically acceptable carrier.

603. The method of any one of claims 593 to 602, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

604. A method of treating a subject having or suspected of having a neoplastic disorder, comprising: (a) administering to the subject an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193, or the composition of any one of claims 194 to 197; (b) detecting one or more neoantigens in the subject after administration of the splicing modulator, antibody-drug conjugate, or composition; ©) comparing the one or more neoantigens to a panel of universal neoantigens; and (d) administering to the subject a universal neoantigen vaccine comprising at least one universal neoantigen present in the subject.

605. The method of claim 604, wherein the universal neoantigen vaccine is administered alone or in combination with at least one additional therapy.

606. The method of claim 605, wherein the at least one additional therapy comprises at least one, at least two, at least three, at least four, or at least five additional therapies.

607. The method of claim 605 or claim 606, wherein the at least one additional therapy comprises repeated administration of the splicing modulator, antibody-drug conjugate, or composition.

608. The method of claim 607, wherein repeated administration of the splicing modulator, antibody-drug conjugate, or composition is initiated before administration of the universal neoantigen vaccine.

609. The method of claim 607, wherein repeated of the splicing modulator, antibody- drug conjugate, or composition is initiated after administration of the universal neoantigen vaccine.

610. The method of claim 607, wherein repeated administration of the splicing modulator, antibody-drug conjugate, or composition is initiated concurrently with administration of the universal neoantigen vaccine.

611. The method of any one of claims 607 to 610, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced as compared to the amount used for initial administration.

612. The method of any one of claims 607 to 611, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition.

613. The method of any one of claims 607 to 612, wherein the amount of the splicing modulator, antibody-drug conjugate, or composition used for repeated administration is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the splicing modulator, antibody-drug conjugate, or composition.

614. The method of any one of claims 605 to 613, wherein the at least one additional therapy comprises administering a checkpoint inhibitor.

615. The method of claim 614, wherein administration of the checkpoint inhibitor is initiated before administration of the universal neoantigen vaccine and / or repeated administration of the splicing modulator, antibody-drug conjugate, or composition.

616. The method of claim 614, wherein administration of the checkpoint inhibitor is initiated after administration of the universal neoantigen vaccine and / or repeated of the splicing modulator, antibody-drug conjugate, or composition.

617. The method of claim 614, wherein administration of the checkpoint inhibitor is initiated concurrently with administration of the universal neoantigen vaccine and / or repeated administration of the splicing modulator, antibody-drug conjugate, or composition.

618. The method of any one of claims 614 to 617, wherein administration of the checkpoint inhibitor is repeated at least once after initial administration.

619. The method of claim 618, wherein the amount of the checkpoint inhibitor used for repeated administration is reduced as compared to the amount used for initial administration.

620. The method of claim 618 or claim 619, wherein the amount of the checkpoint inhibitor used for repeated administration is reduced as compared to a standard dosage of the checkpoint inhibitor.

621. The method of any one of claims 618 to 620, wherein the amount of the checkpoint inhibitor used for repeated administration is reduced by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 75%, or 90%, as compared to a standard dosage of the checkpoint inhibitor.

622. The method of any one of claims 614 to 621, wherein the subject is intolerant, non-responsive, or poorly responsive to the checkpoint inhibitor when administered alone.

623. The method of any one of claims 614 to 622, wherein the checkpoint inhibitor targets CTLA4, PD1, PDL1, OX40, CD40, GITR, LAG3, TIM3, and / or KIR.

624. The method of any one of claims 614 to 623, wherein the checkpoint inhibitor targets CTLA4, OX40, CD40, and / or GITR.

625. The method of any one of claims 614 to 624, wherein the checkpoint inhibitor comprises a cytotoxic T-lymphocyte-associated antigen 4 pathway (CTLA4) inhibitor.

626. The method of claim 625, wherein the CTLA4 inhibitor is an anti-CTLA4 antibody.

627. The method of claim 626, wherein the anti-CTLA4 antibody is ipilimumab.

628. The method of any one of claims 614 to 624, wherein the checkpoint inhibitor comprises a programmed death-1 pathway (PD1) inhibitor.

629. The method of claim 628, wherein the PD1 inhibitor is an anti-PD1 antibody.

630. The method of claim 629, wherein the anti-PD1 antibody is nivolumab.

631. The method of claim 628, wherein the PD1 inhibitor is an anti-PDL1 antibody.

632. The method of claim 631, wherein the anti-PDL1 antibody is atezolizumab.

633. The method of any one of claims 614 to 624, wherein the checkpoint inhibitor comprises a CTLA4 inhibitor and a PD1 inhibitor.

634. The method of claim 633, wherein the CTLA4 inhibitor is an anti-CTLA4 antibody.

635. The method of claim 634, wherein the anti-CTLA4 antibody is ipilimumab.

636. The method of claim 633, wherein the PD1 inhibitor is an anti-PD1 antibody.

637. The method of claim 636, wherein the anti-PD1 antibody is nivolumab.

638. The method of claim 633, wherein the PD1 inhibitor is an anti-PDL1 antibody.

639. The method of claim 638, wherein the anti-PDL1 antibody is atezolizumab.

640. The method of any one of claims 604 to 639, wherein the universal neoantigen vaccine comprises at least one neoantigen peptide.

641. The method of claim 640, wherein the at least one neoantigen peptide ranges from about 10 to about 50 or about 10 to about 35 amino acids in length.

642. The method of claim 640 or claim 641, wherein the at least one neoantigen peptide ranges from about 15 to about 25 amino acids in length.

643. The method of any one of claims 640 to 642, wherein the at least one neoantigen peptide comprises one or more than one universal neoantigen sequence.

644. The method of claim 643, wherein the universal neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

645. The method of claim 644, wherein the universal neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

37.

646. The method of claim 644, wherein the universal neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

39.

647. The method of claim 644, wherein the universal neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

648. The method of claim 643, wherein the universal neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

649. The method of claim 648, wherein the universal neoantigen sequence comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

66.

650. The method of claim 648, wherein the universal neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

651. The method of any one of claims 643 to 650, wherein the universal neoantigen sequence and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

652. The method of any one of claims 643 to 651, wherein the universal neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 45% of subjects in a population of subjects suffering from the neoplastic disorder.

653. The method of any one of claims 643 to 652, wherein the universal neoantigen sequence and / or antigenic portion is capable of eliciting a T-cell response against a tumor present in at least 1%, at least 5%, or at least 10% of a population of subjects suffering from the neoplastic disorder.

654. The method of any one of claims 604 to 639, wherein the universal neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable carrier.

655. The method of claim 654, wherein the at least one necantigen peptide is linked to the pharmaceutically acceptable carrier.

656. The method of claim 654 or claim 655, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

657. The method of any one of claims 654 to 656, wherein the neoantigen peptide and the pharmaceutically acceptable carrier are covalently attached via a linker.

658. The method of any one of claims 654 to 656, wherein the neoantigen peptide and the pharmaceutically acceptable carrier are expressed as a fusion protein.

659. The method of any one of claims 604 to 639, wherein the universal neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable diluent.

660. The method of any one of claims 604 to 639, wherein the universal neoantigen vaccine comprises at least one neoantigen peptide and a pharmaceutically acceptable adjuvant.

661. The method of any one of claims 604 to 639, wherein the universal neoantigen vaccine comprises at least one neoantigen mRNA.

662. The method of claim 661, wherein the at least one necantigen mRNA encodes one or more than one universal neoantigen sequence.

663. The method of claim 662, wherein the universal neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

664. The method of claim 663, wherein the universal neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

37.

665. The method of claim 663, wherein the universal neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

39.

666. The method of claim 663, wherein the universal neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

667. The method of claim 662, wherein the universal neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

668. The method of claim 667, wherein the universal neoantigen sequence comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

66.

669. The method of claim 667, wherein the universal neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

670. The method of any one of claims 662 to 669, wherein the universal neoantigen sequence and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

671. The method of any one of claims 662 to 670, wherein the universal neoantigen sequence and / or antigenic portion is capable of binding to at least one HLA allele expressed in at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 45% of subjects in a population of subjects suffering from the neoplastic disorder.

672. The method of any one of claims 662 to 671, wherein the universal neoantigen sequence and / or antigenic portion is capable of eliciting a T-cell response against a tumor present in at least 1%, at least 5%, or at least 10% of a population of subjects suffering from the neoplastic disorder.

673. The method of any one of claims 604 to 639, wherein the universal neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable carrier.

674. The method of claim 673, wherein the at least one neoantigen mRNA is linked to the pharmaceutically acceptable carrier.

675. The method of claim 673 or claim 674, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

676. The method of any one of claims 604 to 639, wherein the universal neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable diluent.

877. The method of any one of claims 604 to 639, wherein the universal neoantigen vaccine comprises at least one neoantigen mRNA and a pharmaceutically acceptable adjuvant.

678. The method of any one of claims 661 to 677, wherein the neoantigen mRNA is encapsulated by an encapsulating agent.

679. The method of claim 678, wherein the encapsulating agent is a liposome.

680. The method of claim 678, wherein the encapsulating agent is a nanoparticle.

681. The method of any one of claims 604 to 680, wherein the subject has a non- synonymous mutational burden of about 150 mutations or less.

682. The method of any one of claims 604 to 681, wherein the subject has a non- synonymous mutational burden of about 100 mutations or less.

683. The method of any one of claims 604 to 682, wherein the subject has a non- synonymous mutational burden of about 50 mutations or less.

684. The method of any one of claims 604 to 683, wherein the neoplastic disorder is a hematological malignancy or a solid tumor.

685. The method of claim 684, wherein the hematological malignancy is selected from a B-cell malignancy, a leukemia, a lymphoma, and a myeloma.

686. The method of claim 684 or claim 685, wherein the hematological malignancy is selected from acute myeloid leukemia and multiple myeloma.

687. The method of claim 684, wherein the solid tumor is selected from breast cancer, gastric cancer, prostate cancer, ovarian cancer, lung cancer, uterine cancer, salivary duct carcinoma, melanoma, colon cancer, cervical cancer, pancreatic cancer, kidney cancer, colorectal cancer, and esophageal cancer.

688. The method of any one of claims 303 to 687, wherein the antibody-drug conjugate comprises an antibody-drug conjugate of Formula (1): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; Dis D2, D1, D4, D12, or D15:; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

689. The method of claim 688, wherein the antibody or antigen binding fragment targets a HER2-expressing cell.

690. The method of claim 689, wherein the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment.

691. The method of claim 689 or claim 890, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR?2), and SEQ ID NO:3 (HCDRS); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDR®).

692. The method of any one of claims 689 to 691, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

20.

693. The method of claim 688, wherein the antibody or antigen binding fragment targets a CD138-expressing cell.

694. The method of claim 693, wherein the antibody or antigen binding fragment is an anti-CD138 antibody or antigen binding fragment.

695. The method of claim 693 or claim 694, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:7 (HCDR1), SEQ ID NO:8 (HCDR2), and SEQ ID NO:9 (HCDRS3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:10 (LCDR1), SEQ ID NO:11 (LCDR2), and SEQ ID NO:12 (LCDR3).

696. The method of any one of claims 693 to 695, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:21, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

22.

697. The method of claim 688, wherein the antibody or antigen binding fragment targets an EPHA2-expressing cell.

698. The method of claim 697, wherein the antibody or antigen binding fragment is an anti-EPHA2 antibody or antigen binding fragment.

699. The method of claim 697 or claim 698, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:13 (HCDR1), SEQ ID NO:14 (HCDR2), and SEQ ID NO:15 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:16 (LCDR1), SEQ ID NO:17 (LCDR2), and SEQ ID NO:18 (LCDR3).

700. The method of any one of claims 697 to 699, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:23, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

24.

701. The method of any one of claims 688 to 700, wherein the linker is a cleavable linker.

702. The method of claim 701, wherein the cleavable linker comprises MC-Val-Cit- pABC.

703. The method of claim 701, wherein the cleavable linker comprises MC-Val-Ala- PABC.

704. The method of claim 701, wherein the cleavable linker comprises MC-Val-Ala- PAB.

705. The method of any one of claims 688 to 700, wherein the linker is a non- cleavable linker.

706. The method of claim 705, wherein the non-cleavable linker comprises Mal-Hex.

707. The method of claim 705, wherein the non-cleavable linker comprises Mal-Et.

708. The method of claim 705, wherein the non-cleavable linker comprises Mal-Et-O- Et.

708. The method of any one of claims 688 to 708, wherein the splicing modulator comprises D2: (D2).

710. The method of claim 709, wherein the splicing modulator comprises D2 and the linker comprises MC-Val-Ala-pAB.

711. The method of any one of claims 688 to 708, wherein the splicing modulator comprises D1: (D1).

712. The method of claim 711, wherein the splicing modulator comprises D1 and the linker comprises MC-Val-Cit-pABC.

713. The method of any one of claims 688 to 708, wherein the splicing modulator comprises a splicing modulator of Formula (II): (II), or a pharmaceutically acceptable R'is chosen from absent, hydrogen, C+-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Ce heterocyclyl groups, -O-C(=0)- (C4-Cs alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; and R*, R, and R® are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R"7, -0-C(=0)-NRSR'8, C,-Cg alkyl groups, and -NR'SR18: R'® and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-0O-R'"; R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; and Ronn No” Ga "Or ey from Ry Ry Ry Ry , and R3, R4 RS R® R7, R? R'S, R' and R'7 are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C1-Ce alkyl groups, -O-(C1-Cs alkyl) groups, -NR*R8, C4-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C+-Ce alkylalkoxy groups, benzyl groups, and Ca-Cs heterocyclyl groups, wherein at least one of R® and R is hydrogen.

714. The method of any one of claims 688 to 708, wherein the splicing modulator (IV), or a pharmaceutically R'is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, -O-C(=0)-(C4-Ce alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C1-Cs alkyl) groups; and R¢4, RS, and Re are each independently chosen from hydrogen, hydroxyl groups, - O-(C4-Ce alkyl) groups, -O-C(=0)-(C4-Cs alkyl) groups, and C-Ce alkyl groups; R® and R? are each independently chosen from hydrogen, -O-R'7, -O-C(=0)-R'7, -0-C(=0)-NRSR'8, C,-Cg alkyl groups, and -NR'SR18: RS and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R'7, and -C(=0)-O-R'": and R'is chosen from hydrogen, C1-Ce alkyl groups, Ca-Cs cycloalkyl groups, benzyl groups, and Cs-Cs heterocyclyl groups; wherein R', R% R4, R%, R®, R, R8, RS, R'8, and R'” are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C4-Ce alkyl groups, -O-(C+-Cs alkyl) groups, -NR'SR1®, C5-Cq cycloalkyl groups, C1-Ce alkylhydroxy groups, C1-Ce alkylalkoxy groups, benzyl groups, and Ca-Cg heterocyclyl groups, wherein at least one of R® and R? is hydrogen.

715. The method of any one of claims 688 to 708, wherein the splicing modulator (VI), or a pharmaceutically acceptable R! and R® are each independently chosen from hydrogen, C1-Ce alkyl groups, C1-Ce alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C1-Ce alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Ce heterocyclyl groups, -O-C(=0)-(C+-Cs alkyl) groups, and -CDs3; R? is chosen from hydrogen, C+-Cs alkyl groups, C1-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C+-Cs alkylcarboxylic acid groups, C+-Cs alkylhydroxy groups, Cs-Ce cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R¢4, RS, and RE are each independently chosen from hydrogen, hydroxyl groups, - 0O-(C4-Ce alkyl) groups, -O-C(=0)-(C1-Ce alkyl) groups, and C+-Cg alkyl groups: R® and R” are each independently chosen from hydrogen, -O-R"", -O-C(=0)-R", -0-C(=0)-NRSR18, C4-Cg alkyl groups, -NR'R'¢, and a linker; Ris chosen from hydrogen, C1-Cs alkyl groups, -C(=0)-(C1-Cs alkyl) groups, and -CDg; R15 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'"; R17 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Csg heterocyclyl groups: and ais1,2,3,4,56,7,8, 9 0r10; wherein RY, R?, R4, R%, R%, R7, R8, R?, R'%, R'8, R'¢, and R'7 are each independently substituted with O to 3 groups independently chosen from halogens, hydroxyl groups, C1-Cs alkyl groups, -O-(C1-Ces alkyl) groups, -NR SR 8, C3-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Ce alkylalkoxy groups, benzyl groups, and Cs-Ce heterocyclyl groups; wherein at least one of R® and R7 is hydrogen; and wherein R' and R® cannot both be absent 716. The method of any one of claims 688 to 708, wherein the splicing modulator Formula (VIII): or a pharmaceutically acceptable salt thereof, R'is chosen from absent, hydrogen, C+-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Ce heterocyclyl groups, -O-C(=0)- (C4-Cs alkyl) groups, and -CDs; R3 is chosen from hydrogen, C1-Cs alkyl groups, C+-Cs alkylalkoxy groups, C1-Cs alkylamino groups, C1-Cs alkylcarboxylic acid groups, C1-Cs alkylhydroxy groups, Cs-Cs cycloalkyl groups, benzyl groups, Ca-Cs heterocyclyl groups, and -O-C(=0)-(C+-Cs alkyl) groups; R* is chosen from hydrogen, hydroxyl groups, -O-(C1-Cs alkyl) groups, -O-C(=0)- (C1-Cs alkyl) groups, and C4-Cs alkyl groups: and R'is chosen from 3 to 10 membered carbocycles and 3 to 10 membered heterocycles, each of which is substituted with 0 to 3 R?, wherein each R? is independently chosen from halogens, C+-Ce alkyl groups, -O-(C1-Cg)alky! groups, C1-Ces alkylalkoxy groups, C+-Ce alkylhydroxy groups, -S(=O)w-(4 to 7 membered heterocycles), 4 to 7 membered carbocycles, and 4 to 7 membered heterocycles; R'5 and R'® are each independently chosen from hydrogen, R'?, -C(=0)-R"7, and -C(=0)-O-R'""; and R17 is chosen from hydrogen, C1-Cs alkyl groups, Cs-Cs cycloalkyl groups, benzyl groups, and Cs-Csg heterocyclyl groups: wherein RY, R3, R4, R'°, R', R'8, and R'7 are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, C+-Ce alkyl groups, -O-(C+-Cs alkyl) groups, -NR'$R'®, Ca-Cs cycloalkyl groups, C1-Cs alkylhydroxy groups, C1-Cs alkylalkoxy groups, benzyl groups, and Ci-Cg heterocyclyl groups; and wherein each R? is independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl groups, -NR'®R1®, C+-Ce alkyl groups, -(C=0)-(C1-Ce alkyl) groups, -(C=0)-(C1-Cs alkyl)-( Cs-C10 heterocyclyl) groups, -S(=0)w-(C3-Cs heterocyclyl groups), and C+-Ce alkylcarboxylic acid groups, each of which is substituted with 0, 1, or 2 groups independently chosen from halogens, hydroxyl groups, -NR'*R¢, and C4-Ca alkyl groups; and wis 0, 1, or2.

717. The method of any one of claims 688 to 708, wherein the splicing modulator comprises a modulator of the SF3b complex.

718. The method of claim 717, wherein the splicing modulator comprises a pladienolide or a pladienolide derivative.

719. The method of claim 717 or claim 718, wherein the splicing modulator comprises pladienolide D or a pladienolide D derivative.

720. The method of claim 719, wherein the pladienclide D or derivative comprises D2, D1, D4, D8, D10, D11 (E7107), D20, D21, D22, D12, or D25.

721. The method of claim 719 or claim 720, wherein the pladienolide D or derivative comprises D2.

722. The method of claim 719 or claim 720, wherein the pladienclide D or derivative comprises D1.

723. The method of claim 719 or claim 720, wherein the pladienolide D or derivative is a zwitterionic pladienolide D or derivative.

724. The method of claim 723, wherein the zwitterionic pladienolide D or derivative comprises D22 or D25.

725. The method of claim 717 or claim 718, wherein the splicing modulator comprises pladienolide B or a pladienolide B derivative.

726. The method of claim 725, wherein the pladienolide B or derivative comprises D9, D18, D19, or D13.

727. The method of claim 717 or claim 718, wherein the splicing modulator comprises an aryl pladienolide.

728. The method of claim 727, wherein the aryl pladienolide comprises D15, D14, D16, D17, D26, or D33.

729. The method of claim 727 or claim 728, wherein the aryl pladienolide is a zwitterionic aryl pladienolide.

730. The method of claim 729, wherein the zwitterionic aryl pladienolide comprises D313.

731. The method of any one of claims 688 to 708, wherein the splicing modulator comprises D4, D12, D15, D8, D9, D10, D13, D18, D19, D20, D21, D22, D25, or D33.

732. The method of any one of claims 688 to 731, wherein p is from 2 to 8.

733. The method of any one of claims 688 to 732, wherein p is from 4 to 8.

734. The method of any one of claims 688 to 733, wherein pis 4 or 8.

735. A neoantigen vaccine comprising at least one neoantigen peptide, wherein the at least one neoantigen peptide comprises a modified or novel neoantigen sequence induced by contacting a neoplastic cell with an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197.

736. The neoantigen vaccine of claim 735, wherein the at least one neoantigen peptide ranges from about 10 to about 50 or about 10 to about 35 amino acids in length.

737. The neoantigen vaccine of claim 735 or claim 736, wherein the at least one neoantigen peptide ranges from about 15 to about 25 amino acids in length.

738. The neoantigen vaccine of any one of claims 735 to 737, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

739. The neoantigen vaccine of claim 738, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

37.

740. The neoantigen vaccine of claim 738, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

39.

741. The neoantigen vaccine of claim 738, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

742. The neoantigen vaccine of any one of claims 735 to 737, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

743. The neoantigen vaccine of claim 742, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

686.

744. The neoantigen vaccine of claim 742, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

745. The neoantigen vaccine of any one of claims 735 to 744, wherein the modified or novel neoantigen sequence and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

746. The neoantigen vaccine of any one of claims 735 to 745, further comprising a pharmaceutically acceptable carrier.

747. The neoantigen vaccine of claim 746, wherein the at least one neoantigen peptide is linked to the pharmaceutically acceptable carrier.

748. The neoantigen vaccine of claim 746 or claim 747, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

749. The neoantigen vaccine of any one of claims 746 to 748, wherein the necantigen peptide and the pharmaceutically acceptable carrier are covalently attached via a linker.

750. The neoantigen vaccine of any one of claims 746 to 748, wherein the necantigen peptide and the pharmaceutically acceptable carrier are expressed as a fusion protein.

751. The neoantigen vaccine of any one of claims 735 to 745, further comprising a pharmaceutically acceptable diluent.

752. The neoantigen vaccine of any one of claims 735 to 745, further comprising a pharmaceutically acceptable adjuvant.

753. The neoantigen vaccine of any one of claims 735 to 752, wherein the neoplastic cell is present in an in vitro cell culture.

754. The neoantigen vaccine of claim 753, wherein the neoplastic cell is obtained from a subject.

755. The neoantigen vaccine of any one of claims 735 to 752, wherein the neoplastic cell is present in a subject.

756. A neoantigen vaccine comprising at least one neoantigen mRNA, wherein the at least one neoantigen MRNA encodes a modified or novel neoantigen sequence induced by contacting a neoplastic cell with an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 1 to 193 or the composition of any one of claims 194 to 197.

757. The neoantigen vaccine of claim 756, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 37-65.

758. The neoantigen vaccine of claim 757, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

37.

759. The neoantigen vaccine of claim 757, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of SEQ ID NO:

39.

760. The neoantigen vaccine of claim 757, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 46-49.

761. The neoantigen vaccine of claim 756, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 66-93, or an antigenic portion of any one of SEQ ID NOs: 66-93.

762. The neoantigen vaccine of claim 761, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of SEQ ID NO: 66, or an antigenic portion of SEQ ID NO:

68.

763. The neoantigen vaccine of claim 761, wherein the modified or novel neoantigen sequence comprises an amino acid sequence of any one of SEQ ID NOs: 74-77, or an antigenic portion of any one of SEQ ID NOs: 74-77.

764. The neoantigen vaccine of any one of claims 756 to 763, wherein the modified or novel neoantigen sequence and / or antigenic portion ranges from about 10 to about 50, about 10 to about 35, about 15 to about 25, or about 10 to about 20 amino acids in length.

765. The neoantigen vaccine of any one of claims 756 to 764, further comprising a pharmaceutically acceptable carrier.

766. The neoantigen vaccine of claim 765, wherein the at least one neoantigen mRNA is linked to the pharmaceutically acceptable carrier.

767. The neoantigen vaccine of claim 765 or claim 766, wherein the pharmaceutically acceptable carrier is selected from a peptide, a serum albumin, a keyhole limpet hemocyanin, an immunoglobulin, a thyroglobulin, an ovalbumin, a toxoid or an attenuated toxoid derivative, a cytokine, and a chemokine.

768. The neoantigen vaccine of any one of claims 756 to 764, further comprising a pharmaceutically acceptable diluent.

769. The neoantigen vaccine of any one of claims 756 to 764, further comprising a pharmaceutically acceptable adjuvant.

770. The neoantigen vaccine of any one of claims 756 to 769, wherein the neoantigen mRNA is encapsulated by an encapsulating agent.

771. The neoantigen vaccine of claim 770, wherein the encapsulating agent is a liposome.

772. The neoantigen vaccine of claim 770, wherein the encapsulating agent is a nanoparticle.

773. The neoantigen vaccine of any one of claims 756 to 772, wherein the neoplastic cell is present in an in vitro cell culture.

774. The neoantigen vaccine of claim 773, wherein the neoplastic cell is obtained from a subject.

775. The neoantigen vaccine of any one of claims 756 to 772, wherein the neoplastic cell is present in a subject.

776. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a MSLN-expressing cell.

777. The antibody-drug conjugate of claim 776, wherein the antibody or antigen binding fragment is an anti-MSLN antibody or antigen binding fragment.

778. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a FOLH1-expressing cell.

779. The antibody-drug conjugate of claim 778, wherein the antibody or antigen binding fragment is an anti-FOLH1 antibody or antigen binding fragment.

780. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a CDH6-expressing cell.

781. The antibody-drug conjugate of claim 780, wherein the antibody or antigen binding fragment is an anti-CDH6 antibody or antigen binding fragment.

782. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a CEACAMS-expressing cell.

783. The antibody-drug conjugate of claim 782, wherein the antibody or antigen binding fragment is an anti-CEACAMS antibody or antigen binding fragment.

784. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a CFC1B-expressing cell.

785. The antibody-drug conjugate of claim 784, wherein the antibody or antigen binding fragment is an anti-CFC1B antibody or antigen binding fragment.

786. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets an ENPP3-expressing cell.

787. The antibody-drug conjugate of claim 786, wherein the antibody or antigen binding fragment is an anti-ENPP3 antibody or antigen binding fragment.

788. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a FOLR1-expressing cell.

789. The antibody-drug conjugate of claim 788, wherein the antibody or antigen binding fragment is an anti-FOLR1 antibody or antigen binding fragment.

790. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a HAVCR1-expressing cell.

791. The antibody-drug conjugate of claim 790, wherein the antibody or antigen binding fragment is an anti-HAVCR1 antibody or antigen binding fragment.

792. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a KIT-expressing cell.

793. The antibody-drug conjugate of claim 792, wherein the antibody or antigen binding fragment is an anti-KIT antibody or antigen binding fragment.

794. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a MET-expressing cell.

795. The antibody-drug conjugate of claim 794, wherein the antibody or antigen binding fragment is an anti-MET antibody or antigen binding fragment.

796. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a MUC16-expressing cell.

797. The antibody-drug conjugate of claim 796, wherein the antibody or antigen binding fragment is an anti-MUC16 antibody or antigen binding fragment.

798. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a SLC39A6-expressing cell.

799. The antibody-drug conjugate of claim 798, wherein the antibody or antigen binding fragment is an anti-SLC39A6 antibody or antigen binding fragment.

800. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a SLC44A4-expressing cell.

801. The antibody-drug conjugate of claim 800, wherein the antibody or antigen binding fragment is an anti-SLC44A4 antibody or antigen binding fragment.

802. The antibody-drug conjugate of any one of claims 1 to 7, wherein the antibody or antigen binding fragment targets a STEAP1-expressing cell.

803. The antibody-drug conjugate of claim 802, wherein the antibody or antigen binding fragment is an anti-STEAP1 antibody or antigen binding fragment.

804. The antibody-drug conjugate of claim 29, wherein the amino acid unit comprises glutamine-valine-citrulline (Glu-Val-Cit).

805. The antibody-drug conjugate of claim 29, wherein the amino acid unit comprises alanine-alanine-asparagine (Ala-Ala-Asn).

806. The antibody-drug conjugate of claim 48 or claim 49, wherein the cleavable peptide moiety or amino acid unit comprises Glu-Val-Cit.

807. The antibody-drug conjugate of claim 48 or claim 49, wherein the cleavable peptide moiety or amino acid unit comprises Ala-Ala-Asn.

808. The antibody-drug conjugate of any one of claims 55 to 58, wherein the linker comprises MC-Glu-Val-Cit.

809. The antibody-drug conjugate of any one of claims 55 to 58, wherein the linker comprises MC-Ala-Ala-Asn.

810. The antibody-drug conjugate of any one of claims 67 to 71, wherein the linker comprises Glu-Val-Cit-pABC.

811. The antibody-drug conjugate of any one of claims 67 to 71, wherein the linker comprises Ala-Ala-Asn-pABC.

812. The antibody-drug conjugate of any one of claims 74 to 78, wherein the linker comprises Glu-Val-Cit-pAB.

813. The antibody-drug conjugate of any one of claims 74 to 78, wherein the linker comprises Ala-Ala-Asn-pAB.

814. The antibody-drug conjugate of claim 117 or claim 118, wherein the pladienolide D or derivative comprises D4.

815. The antibody-drug conjugate of claim 117 or claim 118, wherein the pladienolide D or derivative comprises D12.

816. The antibody-drug conjugate of claim 125 or claim 126, wherein the aryl pladienolide comprises D15.

817. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing modulator comprises D4:

818. The antibody-drug conjugate of claim 817, wherein the splicing modulator comprises D4 and the linker comprises MC-Val-Cit-pABC.

819. The antibody-drug conjugate of claim 817, wherein the splicing modulator comprises D4 and the linker comprises MC-B-glucuronide.

820. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing modulator comprises D12:

821. The antibody-drug conjugate of 820, wherein the splicing modulator comprises D12 and the linker comprises MC-Val-Cit-pABC.

822. The antibody-drug conjugate of claim 820, wherein the splicing modulator comprises D12 and the linker comprises MC-B-glucuronide.

823. The antibody-drug conjugate of any one of claims 1 to 106, wherein the splicing modulator comprises D15:

824. The antibody-drug conjugate of 823, wherein the splicing modulator comprises D15 and the linker comprises MC-Val-Ala-pAB.

825. The antibody-drug conjugate of claim 137, wherein the antibody or antigen binding fragment targets a cell expressing HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A6, SLC44A4, and / or STEAP1.

826. The antibody-drug conjugate of claim 156, wherein the antibody or antigen binding fragment targets a cell expressing HER2, CD138, EPHA2, MSLN, FOLH1, CDH8, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A8, SLC44A4, and / or STEAP1.

827. An antibody-drug conjugate of Formula (I): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; Dis D4; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

828. The antibody-drug conjugate of claim 827, wherein the antibody or antigen binding fragment targets a HER2-expressing cell.

829. The antibody-drug conjugate of claim 828, wherein the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment.

830. The antibody-drug conjugate of claim 828 or claim 829, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDRS3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDR3).

831. The antibody-drug conjugate of any one of claims 828 to 830, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

20.

832. The antibody-drug conjugate of any one of claims 828 to 831, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

833. The antibody-drug conjugate of any one of claims 828 to 832, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

834. The antibody-drug conjugate of claim 827, wherein the antibody or antigen binding fragment targets a cell expressing HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A6, SLC44A4, and / or STEAP1.

835. An antibody-drug conjugate of Formula (I): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; Dis D12; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

836. The antibody-drug conjugate of claim 835, wherein the antibody or antigen binding fragment targets a HER2-expressing cell.

837. The antibody-drug conjugate of claim 838, wherein the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment.

838. The antibody-drug conjugate of claim 836 or claim 837, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDRS3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDR3).

839. The antibody-drug conjugate of any one of claims 836 to 838, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

20.

840. The antibody-drug conjugate of any one of claims 836 to 839, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

841. The antibody-drug conjugate of any one of claims 836 to 840, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

842. The antibody-drug conjugate of claim 835, wherein the antibody or antigen binding fragment targets a cell expressing HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A6, SLC44A4, and / or STEAP1.

843. An antibody-drug conjugate of Formula (I): Ab-(L-D), (I) wherein Ab is an antibody or antigen binding fragment which targets a neoplastic cell; Dis D15; L is a linker that covalently attaches Ab to D; and pis an integer from 1 to 15.

844. The antibody-drug conjugate of claim 843, wherein the antibody or antigen binding fragment targets a HER2-expressing cell.

845. The antibody-drug conjugate of claim 844, wherein the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment.

846. The antibody-drug conjugate of claim 844 or claim 845, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDRS3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDR3).

847. The antibody-drug conjugate of any one of claims 844 to 846, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:19, and a light chain variable region comprising an amino acid sequence of SEQ ID NO:

20.

848. The antibody-drug conjugate of any one of claims 844 to 847, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

849. The antibody-drug conjugate of any one of claims 844 to 848, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

850. The antibody-drug conjugate of claim 843, wherein the antibody or antigen binding fragment targets a cell expressing HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A6, SLC44A4, and / or STEAP1.

851. The antibody-drug conjugate of any one of claims 827 to 850, wherein the linker is a cleavable linker.

852. The antibody-drug conjugate of claim 851, wherein the cleavable linker comprises MC-Val-Cit-pABC.

853. The antibody-drug conjugate of claim 851, wherein the cleavable linker comprises MC-Val-Ala-pABC.

854. The antibody-drug conjugate of claim 851, wherein the cleavable linker comprises MC-Val-Ala-pAB.

855. The antibody-drug conjugate of claim 851, wherein the cleavable linker comprises MC-Glu-Val-Cit-pABC.

856. The antibody-drug conjugate of claim 851, wherein the cleavable linker comprises MC-Ala-Ala-Asn-pABC.

857. The antibody-drug conjugate of claim 851, wherein the cleavable linker comprises MC-B-glucuronide.

858. The antibody-drug conjugate of any one of claims 827 to 850, wherein the linker is a non-cleavable linker.

859. The antibody-drug conjugate of claim 858, wherein the non-cleavable linker comprises Mal-Hex.

860. The antibody-drug conjugate of claim 858, wherein the non-cleavable linker comprises Mal-Et.

861. The antibody-drug conjugate of claim 858, wherein the non-cleavable linker comprises Mal-Et-O-Et.

862. The antibody-drug conjugate of any one of claims 827 to 861, wherein p is from 1to 10.

863. The antibody-drug conjugate of any one of claims 827 to 862, wherein p is from 21t0 8.

864. The antibody-drug conjugate of any one of claims 827 to 863, wherein p is from 4108.

865. The antibody-drug conjugate of any one of claims 827 to 864, wherein pis 4.

866. The antibody-drug conjugate of any one of claims 827 to 864, wherein p is 8.

867. The antibody-drug conjugate of claim 181, wherein the cleavable linker comprises MC-Glu-Val-Cit-pABC.

868. The antibody-drug conjugate of claim 181, wherein the cleavable linker comprises MC-Ala-Ala-Asn-pABC.

869. A composition comprising multiple copies of the antibody-drug conjugate of any one of claims 776 to 868, wherein the average p of the antibody-drug conjugates in the composition is from about 3.5 to about 5.

5.

870. A composition comprising multiple copies of the antibody-drug conjugate of any one of claims 776 to 868, wherein the average p of the antibody-drug conjugates in the composition is from about 7 to about 9.

871. A method of treating a subject having or suspected of having a neoplastic disorder, comprising administering to the subject a therapeutically effective amount of the antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870.

872. A method of reducing or inhibiting growth of a tumor in a subject having or suspected of having a neoplastic disorder, comprising administering to the subject a therapeutically effective amount of the antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870.

873. A method of determining whether a subject having or suspected of having a neoplastic disorder will be responsive to treatment with the antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870, comprising providing a biological sample from the subject and contacting the biological sample with the antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870.

874. An antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870 for use in the treatment of a neoplastic disorder.

875. Use of an antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870 in the treatment of a neoplastic disorder.

876. Use of an antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870 in a method of manufacturing a medicament for the treatment of a neoplastic disorder.

877. A pharmaceutical composition comprising the antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870, and a pharmaceutically acceptable carrier.

878. A method of producing the antibody-drug conjugate of any one of claims 776 to 868, comprising reacting an antibody or antigen binding fragment with a linker joined to a splicing modulator under conditions that allow conjugation.

879. The method of any one of claims 303 to 687, wherein the antibody-drug conjugate comprises an antibody-drug conjugate of any one of claims 776 to 868.

880. The method of claim 688, wherein the antibody or antigen binding fragment targets a cell expressing HER2, CD138, EPHA2, MSLN, FOLH1, CDH6, CEACAMS, CFC1B, ENPP3, FOLR1, HAVCR1, KIT, MET, MUC16, SLC39A6, SLC44A4, and / or STEAP1.

881. The method of claim 701, wherein the cleavable linker comprises MC-Glu-Val- Cit-pABC.

882. The method of claim 701, wherein the cleavable linker comprises MC-Ala-Ala- Asn-pABC.

883. The method of claim 701, wherein the cleavable linker comprises MC-B- glucuronide.

884. The method of any one of claims 688 to 708, wherein the splicing modulator comprises D4:

885. The method of claim 884, wherein the splicing modulator comprises D4 and the linker comprises MC-Val-Cit-pABC.

886. The method of claim 884, wherein the splicing modulator comprises D4 and the linker comprises MC-B-glucuronide.

887. The method of any one of claims 688 to 708, wherein the splicing modulator comprises D12:

888. The method of claim 887, wherein the splicing modulator comprises D12 and the linker comprises MC-Val-Cit-pABC.

889. The method of claim 887, wherein the splicing modulator comprises D12 and the linker comprises MC-B-glucuronide.

890. The method of any one of claims 688 to 708, wherein the splicing modulator comprises D15: (D15).

891. The method of claim 890, wherein the splicing modulator comprises D15 and the linker comprises MC-Val-Ala-pAB.

892. The method of claim 719 or claim 720, wherein the pladienclide D or derivative comprises D4.

893. The method of claim 719 or claim 720, wherein the pladienolide D or derivative comprises D12.

894. The method of claim 727 or claim 728, wherein the aryl pladienclide comprises D115.

895. A neoantigen vaccine comprising at least one neoantigen peptide, wherein the at least one neoantigen peptide comprises a modified or novel neoantigen sequence induced by contacting a neoplastic cell with an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870.

896. A neoantigen vaccine comprising at least one neoantigen mRNA, wherein the at least one neoantigen MRNA encodes a modified or novel neoantigen sequence induced by contacting a neoplastic cell with an effective amount of a splicing modulator, the antibody-drug conjugate of any one of claims 776 to 868 or the composition of claim 869 or claim 870. (Ab-ADL1-D1), wherein Ab is an antibody or antigen binding fragment covalently bound to a maleimide group of ADL1-D1 through the sulfur atom of a thiol group on the antibody or antigen binding fragment. (Ab-ADL1-D4), wherein Ab is an antibody or antigen binding fragment covalently bound to a maleimide group of ADL1-D4 through the sulfur atom of a thiol group on the antibody or antigen binding fragment. (Ab-ADL1-D12), wherein Ab is an antibody or antigen binding fragment covalently bound to a maleimide group of ADL1-D12 through the sulfur atom of a thiol group on the antibody or antigen binding fragment. Ab-ADL5-D2), to a maleimide group of ADL5-D2 through the sulfur atom of a thiol group on the antibody or antigen binding fragment. (Ab-ADL5-D15), wherein Ab is an antibody or antigen binding fragment covalently bound to a maleimide group of ADL5-D15 through the sulfur atom of a thiol group on the antibody or antigen binding fragment.

902. An antibody-drug conjugate having the structure (Ab-ADL13-D4), wherein Ab is an antibody or antigen binding fragment covalently bound to a maleimide group of ADL13-D4 through the sulfur atom of a thiol group on the antibody or antigen binding fragment.

903. The antibody-drug conjugate of any one of claims 897 to 902, wherein the antibody or antigen binding fragment targets a HER2-expressing cell.

904. The antibody-drug conjugate of claim 903, wherein the antibody or antigen binding fragment is an anti-HER2 antibody or antigen binding fragment.

905. The antibody-drug conjugate of claim 903 or claim 904, wherein the antibody or antigen binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO:1 (HCDR1), SEQ ID NO:2 (HCDR2), and SEQ ID NO:3 (HCDRS3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO:4 (LCDR1), SEQ ID NO:5 (LCDR2), and SEQ ID NO:6 (LCDRS3).

906. The antibody-drug conjugate of any one of claims 903 to 905, wherein the antibody or antigen binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:18, and a light chain variable region comprising an amino acid sequence of SEQ ID NOC:

20.

907. The antibody-drug conjugate of any one of claims 903 to 906, wherein the antibody or antigen binding fragment comprises a human IgG1 heavy chain constant region.

908. The antibody-drug conjugate of any one of claims 903 to 907, wherein the antibody or antigen binding fragment comprises a human Ig kappa light chain constant region.

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