Anti-trop2 antibody-drug conjugates and methods of use

Abstract

Antibodies, antigen-binding fragments, and conjugates ( e.g. , antibody-drug conjugates) thereof that bind TROP2 are disclosed, as well as improved linkers for antibody-drug conjugates. The disclosure further relates to methods and compositions for use in the treatment of, e.g. , cancer by administering the compositions provided herein.

Description

ANTT-TROP2 ANTIBODY-DRUG CONJUGATES AND METHODS OF USE

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 569,028, filed on March 22, 2024, the contents of which are incorporated by reference in their entirety.

[0002] The present disclosure relates to anti-TROP2 antibodies and antigen-binding fragments thereof, as well as conjugates such as antibody-drug conjugates (ADCs), e.g., those comprising eribulin, and their use in the treatment and diagnosis of cancers that express TROP2 and / or are amenable to treatment by disrupting tubulin or by administering a composition disclosed herein.

[0003] Cancer is among the leading causes of morbidity and mortality worldwide, with approximately 14 million new cases and 8.2 million cancer-related deaths in 2012. The most common causes of cancer death are cancers of: lung (1.59 million deaths); liver (745,000 deaths); stomach (723,000 deaths); colorectal (694,000 deaths); breast (521,000 deaths); and esophagus (400,000 deaths). The number of new cancer cases is expected to rise by about 70% over the next two decades, to approximately 22 million new cancer cases per year. World Cancer Report 2014. The incidence rate and mortality of rare cancers, such as bile duct cancer (also known as cholangiocarcinoma) have also been increasing worldwide in the past few decades. Banales et al. (2020) Nat Rev Gastroenterol Hepatol. 17:557-88. Unlike with more common types of cancers, the relative lack of awareness, knowledge, and effective treatment options for rare cancers, e.g., cholangiocarcinoma, has meant that patient prognosis has not improved substantially in the past decade. For example, recent reports suggest that the 5-year survival rate for cholangiocarcinoma is only 7-20%. Thus, there is an unmet need for more effective therapies for patients who suffer from rare cancer types, such as cholangiocarcinoma.

[0004] TROP2 (also known as tumor-associated calcium signal transducer 2) is a transmembrane glycoprotein encoded by the TACSTD2 gene in humans. Researchers have demonstrated that TROP2 is overexpressed in a variety of epithelial carcinomas, including, but not limited to, cholangiocarcinoma, thus making it an attractive target for antibody-based cancer therapy. Furthermore, TROP2 expression has been shown to be associated with increased tumor aggressiveness, metastasis, and decreased patient survival. Cubas et al. (2010) Mol. Cancer. 9:253.

[0005] Recent studies have implicated TROP2 in multiple intracellular signaling pathways that regulate proliferation, survival, self-renewal, and invasion in cells. Shvartsur & Bonavida (2015) Genes & Cancer. 6(3-4):84-105. For example, through its role as a calcium signal transducer, it has been shown to result in the activation of the pro-oncogenic MAPK signaling pathway. Additionally, TROP2 may also play a role in deregulating stem cell functions through the Notch, Hedgehog, and Wnt / |3-catenin pathways. Goldenburg et al. (2018) Oncotarget. 9(48):28989-29006.

[0006] In addition to its role in pro-growth signaling pathways, TROP2 expression has been implicated in the epithelial-to-mesenchymal transition (EMT) process. EMT is a mechanism by which cells achieve phenotypic plasticity, and the process is closely associated with cancer metastasis andrecurrence. He et al. (2017). Mol Cancer. 16:63. EMT is thought to be a key process by which cancer cells gain motility and the ability to migrate and invade other sites in the body. Studies have demonstrated that TROP2 is associated with the epithelial phenotype in certain types of cancers, including lung cancer, breast cancer, prostate cancer, and squamous cell carcinoma. Moreover, within these cancer types, TROP2-expressing epithelial cells lose TROP2 expression upon transitioning to a mesenchymal (i.e., invasive) state. Remsik et al. (2018) Oncotarget. 39(11): 1411-18. It is believed that TROP2 may promote EMT by binding and promoting nuclear accumulation of P-catenin, thereby activating downstream pro-metastatic pathways. Zhao et al. (2019) Cancer Med. 8(3): 1135-1147. TROP2 has also been shown to promote EMT in certain cancers through additional pro-oncogenic signaling axes, such as PI3K-AKT. Li et al. (2017) Oncotarget. 8(29):47052-47063. Indeed, inhibition and / or ablation of TROP2 expression has been shown to prevent the development of metastatic properties in cell lines across a broad spectrum of cancers, including gastric cancer, gall bladder cancer, breast cancer, prostate cancer, hepatocellular carcinoma, pancreatic cancer, and cholangiocarcinoma. Without wishing to be bound by theory, it is believed that inhibition of TROP2, e.g., binding by an anti-TROP2 antibody, antigen-binding fragment, and / or ADC, may reduce or prevent EMT in cancer cells. The role of TROP2 expression in EMT (and its converse pathway, mesenchymal-to-epithelial transition, or MET) is an active field of study and more research will be needed to completely elucidate the role of TROP2 in EMT and / or MET.

[0007] Given the prevalence of TROP2 expression in various cancer types, its role in promoting metastasis, and its association with poor clinical outcome, TROP2 is an attractive target for tumor antigen-specific drug delivery approaches, e.g., an antibody-mediated approach. Antibodies conjugated with cytotoxic compounds such as chemotherapeutics have also been explored to enhance the cell-killing activity of antibody-based drug delivery to tumor cells. Nevertheless, the need remains to provide suitable antibodies and / or ADCs that offer a combination of efficient tumor targeting, on- target effects, and / or reduced off-target effects.

[0008] Eribulin is a synthetic compound of the macrocyclic compound halichondrin B, which has been previously shown to exert potent anti-cancer properties through its disruption of tubulin and microtubule dynamics. Towle et al. (2001) Cancer Res. 61(3): 1013-21. Tubulin makes up dynamic filamentous cytoskeletal proteins that are involved in a variety of cellular functions, including intracellular migration and transport, cell signaling, the maintenance of cell shape, and cell division. Due to their rapid cell division, cancer cells are generally more sensitive to compounds that bind to tubulin and disrupt its normal function, as compared to normal cells. For this reason, tubulin inhibitors and other microtubule-targeted agents have become a promising class of drugs for the treatment of cancer. Dumontet and Jordan (2010) Nat. Rev. DrugDiscov. 9:790-803. Halinchondrin B and eribulin in particular have demonstrated notable anti-cancer activities in vitro and in vivo. Tan et al. (2009) Clin Cancer Res. 15(12): 4213-4219; Vahdat et al. (2009) J. Clin. Oncol. 27(18): 2954-2961. Themesylate salt of eribulin (eribulin mesylate) is currently marketed under the trade name Halaven™ for the treatment of patients with refractory metastatic breast cancer.

[0009] While uses of eribulin have been reported in the art, including in the context of ADCs, there remains an unmet need to deliver eribulin in a targeted fashion to particular tissues, e.g., cancer tissues that express TROP2. Likewise, there remains a need in the art for improved antibodies that bind TROP2 with superior properties, e.g. , with respect to antigen-binding and / or the ability to effectively deliver payloads such as eribulin to a target cell or tissue expressing TROP2.SUMMARY OF THE INVENTION

[0010] In various embodiments, the present disclosure provides, in part, novel antibodies and antigenbinding fragments that are capable of specifically binding TROP2 and may be used alone or linked to one or more additional agents (e.g., as ADCs) and administered as part of pharmaceutical compositions. In some embodiments, the antibodies, antigen-binding fragments, and / or ADCs of the present disclosure may be used to slow, inhibit, and / or reverse tumor growth in mammals, and may be useful for treating human cancer patients.

[0011] The present disclosure more specifically relates, in various embodiments, to antibodies and antibody-drug conjugate compounds that are capable of binding and / or killing TROP2-expressing cells. In various embodiments, the compounds are also capable of internalizing into a target TROP2- expressing cell after binding. ADC compounds comprising a linker that attaches eribulin drug moiety to an antibody moiety are disclosed. An antibody moiety may be a full-length antibody or an antigenbinding fragment.

[0012] In various embodiments, the present disclosure provides an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment binds specifically to human TROP2, and wherein the antibody or antigen-binding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) and three light chain complementarity determining regions (LCDR1 , LCDR2, and LCDR3), wherein the HCDR1 comprises an amino acid sequence of SEQ ID NO: 18, the HCDR2 comprises an amino acid sequence selected from SEQ ID NO: 19 or 20, the HCDR3 comprises an amino acid sequence of SEQ ID NO: 21, the LCDR1 comprises an amino acid sequence selected from SEQ ID NO: 22 or 23, the LCDR2 comprises an amino acid sequence selected from SEQ ID NO: 24 or 25, and the LCDR3 comprises an amino acid sequence of SEQ ID NO: 26, as defined by the Kabat numbering system; or the HCDR1 comprises an amino acid sequence of SEQ ID NO: 27, the HCDR2 comprises an amino acid sequence of SEQ ID NO: 28, the HCDR3 comprises an amino acid sequence of SEQ ID NO: 29, the LCDR1 comprises an amino acid sequence of SEQ ID NO: 30, the LCDR2 comprises an amino acid sequence selected from SEQ ID NO: 31 or 32, and the LCDR3 comprises an amino acid sequence of SEQ ID NO: 33, as defined by the IMGT numbering system; or the HCDR1 comprises anamino acid sequence of SEQ ID NO: 1, the HCDR2 comprises an amino acid sequence selected from SEQ ID NO: 2 or 3, the HCDR3 comprises an amino acid sequence of SEQ ID NO: 4, the LCDR1 comprises an amino acid sequence selected from SEQ ID NO: 5, 6, 7, or 8, the LCDR2 comprises an amino acid sequence of SEQ ID NO: 9, and the LCDR3 comprises an amino acid sequence of SEQ ID NO: 10, as defined by the Kabat numbering system; or the HCDR1 comprises an amino acid sequence of SEQ ID NO: 11, the HCDR2 comprises an amino acid sequence of SEQ ID NO: 12, the HCDR3 comprises an amino acid sequence of SEQ ID NO: 13, the LCDR1 comprises an amino acid sequence selected from SEQ ID NO: 14 or 15, the LCDR2 comprises an amino acid sequence of SEQ ID NO: 16, and the LCDR3 comprises an amino acid sequence of SEQ ID NO: 17, as defined by the IMGT numbering system.

[0013] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 18 (HCDR1), SEQ ID NO: 20 (HCDR2), and SEQ ID NO: 21 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 22 (LCDR1), SEQ ID NO: 24 (LCDR2), and SEQ ID NO: 26 (LCDR3), as defined by the Kabat numbering system. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 18 (HCDR1), SEQ ID NO: 20 (HCDR2), and SEQ ID NO: 21 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 23 (LCDR1), SEQ ID NO: 24 (LCDR2), and SEQ ID NO: 26 (LCDR3), as defined by the Kabat numbering system. In some embodiments, the anti-TROP2 antibody or antigenbinding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 27 (HCDR1), SEQ ID NO: 28 (HCDR2), and SEQ ID NO: 29 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 30 (LCDR1), SEQ ID NO: 31 (LCDR2), and SEQ ID NO: 33 (LCDR3), as defined by the IMGT numbering system.

[0014] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 5 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 14 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system. In some embodiments, the anti-TROP2 antibody or antigenbinding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 11(HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system.

[0015] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence selected from SEQ ID NO: 67, 68,69, 70, or 177, and a light chain variable region comprising an amino acid sequence selected from SEQ ID NO: 71, 72, 167, 73, 74, 75, 76, 187, 77, or 78. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence selected from SEQ ID NO: 53, 54, 55, 56, 174, or 175, and a light chain variable region comprising an amino acid sequence selected from SEQ ID NO: 57, 58, 166, 59, 60, 61, 62, 63, 176, 64, 65, or 66.

[0016] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 72. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 76. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 73. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 77. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 72. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 76. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 73. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 77.

[0017] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable regioncomprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0018] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0019] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a human IgGl, IgG2, IgG3, or IgG4 heavy chain constant region.

[0020] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises an IgGl Fc domain or an IgGl Fc domain mutated to reduce binding to a Fey receptor (FcyR) as compared to an IgGl Fc-containing antibody with a wild-type IgGl Fc domain. In some embodiments, the mutated IgGl Fc domain comprises the mutations L234A, L235A, P238S, H268Q, and K274Q.

[0021] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a human Ig kappa light chain constant region.

[0022] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence selected from SEQ ID NO: 118, 119, 122, 123, 126, 127, or 381 and a light chain comprising an amino acid sequence selected from SEQ ID NO: 129, 130, 133, or 134. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence selected from SEQ ID NO: 96, 97, 100, 101, 104, 105, 179, 181, 183, or 380 and a light chain comprising an amino acid sequence selected from SEQ ID NO: 107, 110, 112, or 115.

[0023] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

[0024] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises part of a bispecific or multi-specific binding construct. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment is linked to a therapeutic agent or detectable agent.

[0025] In various embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof disclosed herein; D is a cytotoxic agent; L is a cleavable linker that covalently attaches Ab to D; and p is an integer from 1 to 8.

[0026] In some embodiments, the cytotoxic agent comprises eribulin or a salt thereof.

[0027] In some embodiments, p is from 2 to 8. In some embodiments, p is 2.

[0028] In some embodiments, the cleavable 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 cytotoxic agent upon cleavage.

[0029] In some embodiments, the cleavable 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 is cleavable by cathepsin. In some embodiments, the cleavable peptidemoiety is cleavable by cathepsin B. In some embodiments, the cleavable peptide moiety is cleavable by legumain.

[0030] In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the amino acid unit comprises valine-citrulline (Val-Cit). In some embodiments, the amino acid unit comprises valine-dimethylated lysine (Val-Lys(Me)2). In some embodiments, the amino acid unit comprises alanine-dimethylated lysine (Ala-Lys(Me)2). In some embodiments, the amino acid unit comprises valine-alanine (Vai- Ala). In some embodiments, the amino acid unit comprises asparagine (Asn). In some embodiments, the amino acid unit comprises aspartic acid (Asp). In some embodiments, the amino acid unit comprises methylated aspartic acid (Asp(OMe)).

[0031] In some embodiments, the cleavable linker attaches to the antibody or antigen-binding fragment via a maleimide (Mai or MAL) moiety. In some embodiments, the Mai moiety comprises a maleimidocaproyl (MC) moiety. In some embodiments, the Mai moiety comprises a dithiomaleimide (DTM) moiety. In some embodiments, the Mai moiety is reactive with a cysteine residue on the antibody or antigen-binding fragment. In some embodiments, the Mai moiety is joined to the antibody or antigen-binding fragment via a cysteine residue on the antibody or antigen-binding fragment.

[0032] In some embodiments, the cleavable linker comprises the Mai moiety and a cleavable peptide moiety. In some embodiments, the Mai moiety attaches the antibody or antigen-binding fragment to the cleavable peptide moiety in the linker. In some embodiments, the cleavable linker comprises Mal- Val-Cit. In some embodiments, the cleavable linker comprises Mal-Val-Lys(Me)2. In some embodiments, the amino acid unit comprises Mal-Ala-Lys(Me)2. In some embodiments, the cleavable linker comprises Mal-Val-Ala. In some embodiments, the cleavable linker comprises Mal-Asn. In some embodiments, the cleavable linker comprises Mal-Asp. In some embodiments, the cleavable linker comprises Mal-Asp(OMe).

[0033] In some embodiments, the cleavable linker comprises at least one spacer unit. In some embodiments, the spacer unit comprises a polyethylene glycol (PEG) moiety. In some embodiments, the PEG moiety comprises -(PEG)m- and m is an integer from 1 to 10. In some embodiments, m is 2. In some embodiments, m is 3. In some embodiments, m is 4.

[0034] In some embodiments, the spacer unit comprises an alkyl moiety. In some embodiments, the alkyl moiety comprises -(CH2)n- and n is an integer from 1 to 10. In some embodiments, n is 5.

[0035] In some embodiments, the spacer unit comprises “C2”

[0036] In some embodiments, the spacer unit comprises C2conjugated to a PEG moiety, wherein the PEG moiety comprises -(PEG)m- and m is an integer from 1 to 4. In some embodiments, m is 1. In some embodiments, m is 2. In some embodiments, m is 3.

[0037] In some embodiments, the spacer unit comprises “C2(PEG)2” as shown in the following chemical structure:

[0038] In some embodiments, the spacer unit attaches to the antibody or antigen-binding fragment via the maleimide (Mai) moiety ("Mal-spacer unit"). In some embodiments, the cleavable linker comprises the Mal-spacer unit and the cleavable peptide moiety. In some embodiments, the Mal- spacer unit attaches the antibody or antigen-binding fragment to the cleavable peptide moiety in the linker.

[0039] In some embodiments, the Mal-spacer unit comprises a PEG moiety. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)2-Val-Cit. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)3-Val-Cit. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)4- Val-Cit. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)2-Val-Lys(Me)2. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)2-Ala-Lys(Me)2. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)2-Val-Ala. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)2-Asn. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)2-Asp. In some embodiments, the Mal-spacer unit comprises Mal-(PEG)2-Asp(OMe).

[0040] In some embodiments, the Mal-spacer unit comprises a C2moiety.

[0041] In some embodiments, the Mal-spacer unit comprises C2conjugated to a PEG moiety, wherein the PEG moiety comprises -(PEG)m- and m is an integer from 0 to 4. In some embodiments, m is 2.

[0042] In some embodiments, the Mal-spacer unit comprises a C2(PEG)mmoiety. In some embodiments, the Mal-spacer unit comprises Mal-C2(PEG)m-Val-Cit. In some embodiments, the Mal- spacer unit comprises Mal-C2(PEG)m-Val-Lys(Me)2. In some embodiments, the Mal-spacer unit comprises Mal-C2(PEG)m-Ala-Lys(Me)2. In some embodiments, the Mal-spacer unit comprises Mal- C2(PEG)m-Val-Ala. In some embodiments, the Mal-spacer unit comprises Mal-C2(PEG)m-Asn. In some embodiments, the Mal-spacer unit comprises Mal-C2(PEG)m-Asp. In some embodiments, the Mal-spacer unit comprises Mal-C2(PEG)m-Asp(OMe). In some embodiments, m is an integer from 0 to 4. In some embodiments, m is 2.

[0043] In some embodiments, the cleavable moiety in the linker is directly joined to the cytotoxic agent.

[0044] In some embodiments, a spacer unit attaches the cleavable moiety in the linker to the cytotoxic agent. In some embodiments, cleavage of the conjugate releases the cytotoxic agent from the antibody and linker. In some embodiments, the spacer unit attaching the cleavable moiety in the linker to the cytotoxic agent is self-immolative. In some embodiments, the spacer unit attaching the cleavable moiety in the linker to the cytotoxic agent comprises a p-aminobenzyl (pAB). In some embodiments, the spacer unit attaching the cleavable moiety in the linker to the cytotoxic agent comprises a p- aminobenzyloxycarbonyl (pABC). In some embodiments, the pAB attaches the cleavable moiety inthe linker to the cytotoxic agent. In some embodiments, the cytotoxic agent is eribulin. In some embodiments, the pAB covalently attaches to eribulin via a C-35 amine. In some embodiments, the cleavable moiety comprises Val-Cit, Vai-Ala, Val-Lys(Me)2, Ala-Lys(Me)2, Asn, Asp, or Asp(OMe).

[0045] In some embodiments, the cleavable linker comprises Val-Cit-pABC. In some embodiments, the cleavable linker comprises Val-Ala-pABC. In some embodiments, the cleavable linker comprises Val-Lys(Me)2-pABC.

[0046] In some embodiments, the cleavable linker comprises DTM-Asn.

[0047] In some embodiments, the cleavable linker comprises Mal-(PEG)2-Val-Cit-pABC. In some embodiments, the cleavable linker comprises Mal-(PEG)3-Val-Cit-pABC. In some embodiments, the cleavable linker comprises Mal-(PEG)4-Val-Cit-pABC. In some embodiments, the cleavable linker comprises Mal-(PEG)2-Val-Lys(Me)2-pABC. In some embodiments, the cleavable linker comprises Mal-(PEG)2-Val-Ala-pABC. In some embodiments, the cleavable linker comprises Mal-C2(PEG)2- Val-Cit-pABC. In some embodiments, the cleavable linker comprises Mal-C2(PEG)2-Val-Lys(Me)2- pABC. In some embodiments, the cleavable linker comprises Mal-C2(PEG)2-Val-Ala-pABC. In some embodiments, the cleavable linker comprises Mal-C2(PEG)2-Ala-Lys(Me)2-pABC.

[0048] In some embodiments, the antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 5 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system. In some embodiments, the antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system. In some embodiments, the antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 14 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system. In some embodiments, the antibody or antigen-binding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system.

[0049] In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the antibody or antigen-binding fragment comprises a heavychain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0050] In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 96 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 179 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 96 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 179 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 104 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 183 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 104 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 183 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

[0051] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Val-Cit-pABC; and p is an integer from 1 to 8.

[0052] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Val-Cit-pABC; and p is an integer from 1 to 8.

[0053] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Val-Ala-pABC; and p is an integer from 1 to 8.

[0054] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I)wherein Ab is an internalizing anti-TR0P2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Val-Ala-pABC; and p is an integer from 1 to 8.

[0055] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Asn; and p is an integer from 1 to 8.

[0056] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Asn; and p is an integer from 1 to 8.

[0057] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprisingamino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Val-Cit-pABC, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

[0058] In some embodiments, m is 2.

[0059] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Val-Cit-pABC, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

[0060] In some embodiments, m is 2.

[0061] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Val-Ala-pABC, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

[0062] In some embodiments, m is 2.

[0063] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I)wherein Ab is an internalizing anti-TR0P2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Val-Ala-pABC, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

[0064] In some embodiments, m is 2.

[0065] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Asn, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

[0066] In some embodiments, m is 2.

[0067] In some embodiments, the present disclosure provides an antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an internalizing anti-TROP2 antibody or internalizing antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Asn, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

[0068] In some embodiments, m is 2.

[0069] In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0070] In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0071] In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 183 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 179 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 179 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 183 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

[0072] In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 104 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ IDNO: 96 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 104 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 96 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

[0073] In some embodiments, p is 2.

[0074] In some embodiments, p is determined by hydrophobic interaction chromatography-high performance liquid chromatography (HIC-HPLC). In some embodiments, p is determined by reversephase liquid chromatography-mass spectrometry (LC-MS).

[0075] In some embodiments, the cleavable linker covalently attaches to the cytotoxic agent via a C- 35 amine. In some embodiments, the cleavable linker covalently attaches to the antibody or antigenbinding fragment via a cysteine or a lysine.

[0076] In various embodiments, the present disclosure provides a composition comprising multiple copies of an antibody-drug conjugate disclosed herein. In some embodiments, the average p of the antibody-drug conjugates in the composition is about 1 to about 3. In some embodiments, the average p is about 2.

[0077] In various embodiments, the present disclosure provides a pharmaceutical composition comprising an antibody-drug conjugate disclosed herein and a pharmaceutically acceptable carrier.

[0078] In various embodiments, the present disclosure provides one or more nucleic acid(s) encoding an antibody or antigen-binding fragment disclosed herein. In some embodiments, the present disclosure provides a host cell comprising the one or more nucleic acids. In some embodiments, the present disclosure provides a method of producing an antibody or antigen-biding fragment disclosed herein, comprising culturing the host cell under conditions sufficient to produce the antibody or antigen-binding fragment.

[0079] In various embodiments, the present disclosure provides a method of producing an antibodydrug conjugate, comprising reacting an antibody or antigen-binding fragment disclosed herein with a cleavable linker joined to eribulin under conditions that allow conjugation.

[0080] In other embodiments, the present disclosure provides an antibody-drug conjugate of Formula (III): wherein:Ab is an antibody or antigen-binding fragment thereof;D is a cytotoxic agent;Y is a cleavable moiety;Z is absent or a spacer unit; and p is an integer from 1 to 8.

[0081] In some embodiments, the cytotoxic agent comprises eribulin or a salt thereof.

[0082] In some embodiments, p is from 2 to 8. In some embodiments, p is 2.

[0083] In some embodiments, the bond to the Ab is on a cysteine residue of the antibody or antigenbinding fragment. In some embodiments, the bond to the Ab is on a cysteine-80 residue on the light chain of the antibody or antigen-binding fragment. In some embodiments, the bond to the Ab is on a cysteine- 149 residue on the light chain of the antibody or antigen-binding fragment. In some embodiments, the bond to the Ab is on a cysteine- 118 residue on the heavy chain of the antibody or antigen-binding fragment. In some embodiments, the bond to the Ab is on a cysteine- 140 residue on the heavy chain of the antibody or antigen-binding fragment. In some embodiments, the bond to the Ab is on a cysteine-239 residue on the heavy chain of the antibody or antigen-binding fragment.

[0084] In some embodiments, the cleavable moiety comprises a cleavable peptide moiety. In some embodiments, the cleavable peptide moiety is cleavable by an enzyme. In some embodiments, the cleavable peptide moiety is cleavable by cathepsin or legumain. In some embodiments, the cleavable peptide moiety is cleavable by cathepsin B.

[0085] In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the amino acid unit comprises valine-citrulline (Val-Cit), valine-dimethylated lysine (Val-Lys(Me)2), alanine-dimethylated lysine (Ala-Lys(Me)2), valine-alanine (Vai- Ala), asparagine (Asn), aspartic acid (Asp), or methylated aspartic acid (Asp(OMe)). 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 Asn. In some embodiments, the amino acid unit comprises Asp.

[0086] In some embodiments, Z is absent, and the cleavable moiety is directly joined to the cytotoxic agent. In some embodiments, -Y-Z- comprises Asn. In some embodiments, -Y-Z- comprises Asp. In some embodiments, D comprises eribulin or a salt thereof.

[0087] In some embodiments, Z is a spacer unit which attaches the cleavable moiety to the cytotoxic agent.

[0088] In some embodiments, the spacer unit attaching the cleavable moiety to the cytotoxic agent is self-immolative. In some embodiments, the spacer unit attaching the cleavable moiety to the cytotoxic agent comprises a p-aminobenzyloxycarbonyl (pABC). In some embodiments, the cytotoxic agent is eribulin, and the pABC covalently attaches to eribulin via a C-35 amine.

[0089] In some embodiments, -Y-Z- comprises Val-Cit-pABC, Val-Ala-pABC, Val-Lys(Me)2-pABC, or Ala-Lys(Me)2-pABC. In some embodiments, -Y-Z- comprises Val-Cit-pABC. In someembodiments, -Y-Z- comprises Val-Ala-pABC. In some embodiments, D comprises eribulin or a salt thereof.

[0090] In some embodiments, Ab is an anti-TROP2 antibody or antigen-binding fragment disclosed herein.

[0091] In various embodiments, the present disclosure provides a composition comprising multiple copies of the antibody-drug conjugate of Formula (II) or Formula (III). In some embodiments, the average p of the antibody-drug conjugates in the composition is about 1 to about 3. In some embodiments, the average p is about 2.

[0092] In various embodiments, the present disclosure provides a compound of Formula (Ila):, wherein:D is a cytotoxic agent;Y is a cleavable moiety; andZ is absent or a spacer unit.

[0093] In some embodiments, the cytotoxic agent comprises eribulin or a salt thereof.

[0094] In some embodiments, the cleavable moiety comprises a cleavable peptide moiety. In some embodiments, the cleavable peptide moiety is cleavable by an enzyme. In some embodiments, the cleavable peptide moiety is cleavable by cathepsin or legumain. In some embodiments, the cleavable peptide moiety is cleavable by cathepsin B.

[0095] In some embodiments, the cleavable peptide moiety comprises an amino acid unit. In some embodiments, the amino acid unit comprises valine-citrulline (Val-Cit), valine-dimethylated lysine (Val-Lys(Me)2), alanine-dimethylated lysine (Ala-Lys(Me)2), valine-alanine (Vai- Ala), asparagine (Asn), aspartic acid (Asp), or methylated aspartic acid (Asp(OMe)). 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 Asn.

[0096] In some embodiments, Z is absent and the cleavable moiety is directly joined to the cytotoxic agent. In some embodiments, -Y-Z- comprises Asn. In some embodiments, -Y-Z- comprises Asp. In some embodiments, D comprises eribulin or a salt thereof.

[0097] In some embodiments, Z is a spacer unit which attaches the cleavable moiety to the cytotoxic agent. In some embodiments, the spacer unit attaching the cleavable moiety to the cytotoxic agent is self-immolative. In some embodiments, the spacer unit attaching the cleavable moiety to the cytotoxic agent comprises a p-aminobenzyloxycarbonyl (pABC). In some embodiments, the pABC covalently attaches to eribulin via a C-35 amine.

[0098] In some embodiments, -Y-Z- comprises Val-Cit-pABC, Val-Ala-pABC, or Val-Lys(Me)2- pABC, Ala-Lys(Me)2-pABC. In some embodiments, -Y-Z- comprises Val-Cit-pABC. In some embodiments, -Y-Z- comprises Val-Ala-pABC. In some embodiments, D comprises eribulin or a salt thereof.

[0099] In various embodiments, the present disclosure provides a method of preparing the antibodydrug conjugate of Formula (II). In some embodiments, the method comprises:- providing one or more compounds of Formula (Ila), wherein: D is the cytotoxic agent; Y is the cleavable moiety; and Z is absent or the spacer unit; and- conjugating the one or more compounds of Formula (Ila) to an antibody or antigen-binding fragment, to provide an antibody-drug conjugate of Formula (II):wherein Ab is the antibody or antigen-binding fragment.

[0100] In various embodiments, the present disclosure provides a method of preparing the antibodydrug conjugate of Formula (III). In some embodiments, the method comprises:- providing one or more compounds of Formula (Ila), wherein: D is the cytotoxic agent; Y is the cleavable moiety; and Z is absent or the spacer unit;- conjugating the one or more compounds of Formula (Ila) to an antibody or antigen-binding fragment, to provide an antibody-drug conjugate of Formula (II):wherein Ab is the antibody or antigen-binding fragment; and- hydrolyzing the succinimide ring in the compound of Formula (II), to provide the compound ofFormula (III)

[0101] In some embodiments, the step of hydrolyzing the succinimide ring in the compound of Formula (II) comprises a pH from about 7.4 to about 9.2. In some embodiments, the pH is from about 7.4 to about 8.5. In some embodiments, the pH is about 7.4.

[0102] In some embodiments, the step of hydrolyzing the succinimide ring in the compound of Formula (II) comprises a temperature of about 37 °C. In some embodiments, the step of hydrolyzing the succinimide ring in the compound of Formula (II) is completed in about 24 hours or less.

[0103] In various embodiments, the present disclosure provides a method of treating a patient having or at risk of having a cancer that expresses TROP2, comprising administering to the patient a therapeutically effective amount of an antibody or antigen-binding fragment disclosed herein. In various embodiments, the present disclosure provides a method of treating a patient having or at risk of having a cancer that expresses TROP2, comprising administering to the patient a therapeutically effective amount of an antibody-drug conjugate disclosed herein. In various embodiments, the present disclosure provides a method of treating a patient having or at risk of having a cancer that expresses TROP2, comprising administering to the patient a therapeutically effective amount of a composition disclosed herein. In various embodiments, the present disclosure provides a method of treating a patient having or at risk of having a cancer that expresses TROP2, comprising administering to the patient a therapeutically effective amount of a pharmaceutical composition disclosed herein. In some embodiments, the TROP2-expressing cancer is a cholangiocarcinoma, bladder cancer, breast cancer, cervical carcinoma, colorectal cancer, esophageal cancer, gastric cancer, glioma, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, or skin cancer. In some embodiments, the TROP2-expressing cancer is a cholangiocarcinoma, breast cancer, or NSCLC. In some embodiments, the patient is intolerant, non-responsive, or poorly responsive to treatment with eribulin when administered alone.

[0104] In various embodiments, the present disclosure provides a method of reducing or inhibiting growth of a TROP2 -expressing tumor, comprising administering a therapeutically effective amount of an antibody or antigen-binding fragment disclosed herein. In various embodiments, the present disclosure provides a method of reducing or inhibiting growth of a TROP2-expressing tumor, comprising administering a therapeutically effective amount of an antibody-drug conjugate disclosed herein. In various embodiments, the present disclosure provides a method of reducing or inhibiting growth of a TROP2 -expressing tumor, comprising administering a therapeutically effective amount of a composition disclosed herein. In various embodiments, the present disclosure provides a method of reducing or inhibiting growth of a TROP2-expressing tumor, comprising administering a therapeutically effective amount of a pharmaceutical composition disclosed herein. In someembodiments, the tumor is a TROP2-expressing cholangiocarcinoma, bladder cancer, breast cancer, esophageal cancer, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, or skin cancer. In some embodiments, the tumor is a cholangiocarcinoma.BRIEF DESCRIPTION OF THE DRAWINGS

[0105] FIG. 1 A shows FACS analysis of folate receptor alpha (FRA), HER2, and TROP2 expression on human breast cancer HCC1954 cell line. FIGs. IB and 1C show average tumor volume and body weight change after single-dose treatment with the indicated compound in a human breast cancer HCC-1954 xenograft model.

[0106] FIG. 2A shows average tumor volumes in NCI-H2110 NSCLC xenograft models upon single-dose treatment with anti-TROP2-162-46.2-SN-38 or anti-FRa-eribulin. FIGs. 2B and 2C show average tumor volumes and body weight for various doses of anti-TROP2-162-46.2-eribulin ADC compared to the unconjugated antibody or eribulin.

[0107] FIGs. 3A and 3B show average tumor volume and relative body weight normalized by day of treatment with a single dose of each compound at the indicated concentration in a WHIM5 TNBC PDx model.

[0108] FIGs. 4A and 4B show average tumor volume and weight in CTG-1258 or CTG-1388 upon single-dose treatment of the indicated compound.

[0109] FIG. 5 shows pre- and post-immunization blood samples from rabbits diluted and analyzed for human TROP2 reactivity by ELISA.

[0110] FIG. 6A shows analysis of overlapping epitopes on hTROP2-Fc for each indicated antibody pair. FIG. 6B shows groupings of antibodies with similar overlapping profiles. FIG. 6C shows analysis of overlapping epitopes on hTROP2-Fc for each indicated antibody pair. FIG. 6D shows grouping of antibodies with similar overlapping profiles.

[0111] FIG. 7 shows correlation between TROP2 affinity and IC50in BxPC3 cells.

[0112] FIG. 8 shows rabbit CDRs grafted onto the closest human germline frameworks. The frameworks (FR) and CDRs are shown above each clone as defined by Kabat (top) and IMGT (bottom). Residues that may impact antigen binding were retained in FRH2 and FRL1. Rabbit residues are in bold, humanized residues are underlined.

[0113] FIGs. 9A and 9B show in vitro cytotoxicity screening of humanized anti-TROP2 ADCs in a variety of cell types. FIG. 9C shows ADC IC50values and max killing (%) for the identified ADCs in AsPCl, BxPC3, and SNU-308 cells. Fig. 9D shows percent cytotoxicity at different ADC concentrations for AsPCl, BxPC3, and SNU-308 cells.

[0114] FIG. 10 shows internalization of anti-TROP2 antibodies using NCI-H2110 and MDA-MB- 231 cell lines.

[0115] FIG. 11 shows rabbit CDRs grafted onto the closest human germline frameworks. The FRs and CDRs are shown above each clone as defined by Kabat (top) and IMGT (bottom). Residues that may impact antigen binding were retained in FRH2 and FRL1. Rabbit residues are in bold, humanized residues are underlined.

[0116] FIG. 12A shows the ECso of 16K21 Hl-3 and Ll-3, 17124 Hl-3 and Ll-3, and 20E16 Hl-3 and Ll-2 for binding human TROP2-ECD as determined by ELISA. FIG. 12B shows the EC50of each indicated clone for binding to human TROP2-ECD as determined by ELISA.

[0117] FIG. 13 shows polyspecificity assessment of control versus anti-TROP2 antibodies. Insulin, ssDNA, dsDNA, cardiolipin, LPS, or KLH were coated on wells of a 96-well plate.

[0118] FIGs. 14A, 14B, 14C, 14D, 14E, 14F, and 14G show the thermal stability of chimeric (xi) and humanized (zu) anti-TROP2 antibodies analyzed by DSC.

[0119] FIG. 15 shows MAAS mutations.

[0120] FIG. 16A shows neutrophil differentiation over 14 days upon indicated cytokine treatment as monitored by FACS. FIG. 16B shows the percentage of viable CD66b+ cells after incubation for four days with various concentrations of anti-TROP2-ADCs with wild-type or mutant Fes in the presence or absence of Fc blocker as determined by FACS.

[0121] FIG. 17 shows immunogenicity of antibody clones predicted by Abzena’s iTope in silico immunogenicity assessment tool.

[0122] FIG. 18A shows a disulfide re-bridging strategy and the DTM-N-eribulin linker payload.FIG. 18B shows IC50values of the indicated ADC in various cell lines.

[0123] FIG. 19 shows linker-eribulin conjugates.

[0124] FIG. 20 shows percent growth inhibition of TROP2-expressing cells treated with anti- TROP2-ADCs in mono- and co-cultured in vitro bystander assay.

[0125] FIG. 21 shows the thermal stability of the indicated linkers over time. HIC = hydrophobic interaction chromatography.

[0126] FIGs. 22A, 22B, 22C, 22D, and 22E show mouse plasma stability of RESPECT-L linkers. FIG. 22 A shows the average DAR of immunocaptured samples as analyzed by LC-MS. FIG. 22B shows percent change in DAR of immunocaptured samples. FIGs. 22C and 22D show free payload (ng / mL or percentage in plasma) in the immunodepleted plasma samples as analyzed by LC-MS after organic extraction of the free payload. FIG. 22E shows the percentage of hydrolysis of the linker for each sample as determined by LC-MS.

[0127] FIG. 23 shows average tumor volume in NSCLC NCI-H2110 xenograft model treated with a single dose of the indicated compounds at 10 mg / kg.

[0128] FIG. 24 shows average tumor volume in NSCLC NCI-H2110 xenograft model treated with subcutaneous injection of a single dose of 16K21H1L1-Eribulin, 17I24H1L1-Eribulin, or IMMU-132 (7.5 mg / kg).

[0129] FIG. 25 shows the anti-tumor activity of 16K21HlLl-ADCs comparing RESPECT-L conjugation ((PEG)2-VCP-eribulin) and re-bridging conjugation (DTM-N-eribulin).

[0130] FIGs. 26A, 26B, 26C, and 26D show the in vivo anti-tumor activity of various RESPECT-L linkers. The anti-tumor activity of 16K21HlLl-ADCs with various PEG lengths (FIG. 26A), 16K21H1L1- and 17I24HlLl-ADCs with various cathepsin-cleavable linkers (FIGs. 26B and26C), and 16K21HlLl-ADCs with legumain-cleavable linkers (FIG. 26D) was evaluated inNSCLC NCI- H2110 xenograft model.

[0131] FIGs. 27A, 27B, 27C, 27D, 27E, 27F, and 27G show in vitro cytotoxicity of humanized monoclonal antibodies and linkers.

[0132] FIGs. 28A, 28B, 28C, and 28D show IC50values for various cell lines treated with the indicated ADCs.

[0133] FIG. 29 shows in vivo analysis of the indicated anti-TROP2-eribulin ADCs.

[0134] FIG. 30 shows an analysis of hydrolysis conditions for various maleimide-conjugated eribulin linkers.

[0135] FIG. 31A shows percent hydrolysis for antibody-drug conjugates comprising a (PEG)2spacer unit conjugated to various cleavable moieties and at various pH. FIG. 31B shows percent hydrolysis for antibody-drug conjugates comprising a C2(PEG)2spacer unit conjugated to various cleavable moieties and at various pH. FIG. 31C shows percent hydrolysis for antibody-drug conjugates comprising a C2spacer unit conjugated to various cleavable moieties and at various pH.

[0136] FIG. 32A shows percent hydrolysis for antibody-drug conjugates comprising a Val-Cit- pABC (VCP) cleavable moiety conjugated to various spacer units and at various pH. FIG. 32B shows percent hydrolysis for antibody-drug conjugates comprising an asparagine (N) cleavable moiety conjugated to various spacer units and at various pH.

[0137] FIGs. 33A shows ADC stability of ADCs comprising VCP and C2(PEG)1, C2(PEG)2, (PEG)2, or C2in buffer or plasma. FIG. 33B shows ADC stability of ADCs comprising N and C2(PEG)2, C2(PEG)1, (PEG)2, or C2in buffer or plasma. “% DAR” represents the percentage of intact ADC relative to the initial DAR at the start of the experiment.

[0138] FIG. 34 shows in vitro cytotoxicity of humanized monoclonal antibodies conjugated to various linkers.

[0139] FIG. 35A shows in vivo tumor volume results after treatment with ADCs comprising C2(PEG)2. FIG. 35B shows in vivo tumor volume results after treatment with ADCs comprising (PEG)2. FIG. 35C shows in vivo tumor volume results after treatment with ADCs comprising C2.DETAILED DESCRIPTION

[0140] 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.

[0141] Throughout this text, the descriptions refer to compositions and methods of using said 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 said 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.

[0142] 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.

[0143] It is 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 sub-combination.Definitions

[0144] 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.

[0145] As used herein, the singular forms “a,” “an,” and “the” include plural forms unless the context clearly dictates otherwise.

[0146] The terms “about” or “approximately” in the context of numerical values and ranges refer 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.

[0147] 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,” “cytotoxic agent,” “drug,” or “drug moiety” refers to an agent that is capable of modulating a biological process and / or has biological activity.

[0148] The terms “antibody-drug conjugate,” “antibody conjugate,” “immunoconjugate,” and “ADC” are used interchangeably, and refer to a compound or derivative thereof that is linked to an antibody (e.g., an anti-TROP2 antibody) and may be defined by the generic formula: Ab-(L-D)p(Formula (I)), wherein Ab = an antibody moiety (i.e., antibody or antigen-binding fragment), L = a linker moiety, D = a drug moiety, and p = the number of drug moieties per antibody moiety. In some embodiments, the linker L includes a cleavable moiety between the antibody or antigen-binding fragment and the therapeutic compound. In some embodiments, the linker L includes a cleavable moiety that can be attached to either or both the antibody or antigen-binding fragment and to the therapeutic compound, e.g., by spacer unit(s). Exemplary cleavable linkers are described and exemplified herein.

[0149] 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 (HC) of an antibody is composed of a heavy chain variable domain (VH) and a heavy chain constant region (CH). The light chain (LC) is composed of a light chain variable domain (VL) and a light chain constant domain (CL). As used herein, the terms “domain” and “region” maybe used interchangeably (e.g., the term “variable domain” may be used interchangeably with the term “variable region” and understood to refer to the same part of the antibody). 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; also referred to as “hypervariable regions”) within four framework regions (FR1, FR2, FR3, and FR4) arranged from N terminus to C terminus: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4. CDRs may be identified according to the Kabat and / or IMGT numbering systems. Kabat, Sequences of Proteins of Immunological Interest (National Institutes of Health, Bethesda, Md. (1987 and 1991); International ImMunoGeneTics Information System (IMGT®). 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')2, Fv, and single chain antibodies. An antibody can be any one of the five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, or subclasses thereof (e.g., isotypes IgGl, IgG2, IgG3, IgG4). An antibody of any of the aforementioned classes or subclasses can also comprise one of two functionally similar classes of light chains: IgK (also referred to herein as “Ig kappa” or “kappa”) and IgX (also referred to herein as “Ig lambda” or “lambda”). The term antibody 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.

[0150] 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.

[0151] 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.

[0152] The term “human antibody,” as used herein, refers to an antibody produced by a human or an antibody having an amino acid sequence of an antibody produced by a human.

[0153] 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 regions 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. The humanized antibody can also be further modified by the substitution of residues in the Fc domain to reduce its binding to various cell receptors, such as a Fey receptor (FcyR), and other immune molecules.

[0154] 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 particularmethod. 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, e.g., Clackson et al. (1991) Nature 352:624-8, and Marks et al. (1991) J. Mol. Biol. 222:581-97.

[0155] 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 an antibody 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 an antibody 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.

[0156] The term “antigen-binding fragment” or “antigen-binding portion” of an antibody, as used herein, refers to one or more fragments of an antibody that retain the ability to specifically bind to an antigen (e.g., TROP2). Antigen-binding fragments preferably 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 antigenbinding 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 VL, VH, CL, and Cm 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 VH and Cm domains; (iv) a Fv fragment consisting of the VL and VH domains of a single arm of an antibody; (v) a dAb fragment, which comprises a single variable domain, e.g. , a VH domain, see, e.g. , Ward et al. (1989) Nature 341 :544-6; and Winter et al., WO 90 / 05144; and (vi) an isolated complementarity determining region (CDR). Furthermore, although the two domains of the Fv fragment, VL and VH, 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 VL and VH 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 VH and VL 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, e.g. , by cleavage of the intact protein, e.g. , by protease or chemical cleavage.

[0157] The term “anti-TROP2 antibody” or “antibody that specifically binds TROP2” refers to any form of antibody or fragment thereof that specifically binds TROP2, and encompasses monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, and biologically functional antibody fragments so long as they specifically bind TROP2. Preferably the anti-TROP2 antibody used in the ADCs disclosed herein is an internalizing antibody or internalizing antibody fragment. 17124, 16K21, and 20E16 are exemplary internalizing anti-human TROP2 antibodies. Sacituzumab and datopotamab are also exemplary internalizing anti-human TROP2 antibodies. As used herein, the terms “specific,” “specifically binds,” and “binds specifically” refer to the selective binding of the antibody to the target antigen or epitope over alternative antigens or epitopes. 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 5 times, or preferably 7 or 10 times, more affinity than to an irrelevant antigen or antigen mixture, then it is considered to be specific, e.g., as measured by surface plasmon resonance, e.g., BIAcore® analysis. In one embodiment, a specific antibody is one that binds the TROP2 antigen, but does not bind (or exhibits minimal binding) to other antigens.

[0158] The term “cancer” refers to the physiological condition in mammals in which a population of cells is characterized by unregulated cell growth. Examples of cancers include, but are not limited to, carcinoma, lymphoma, blastoma, sarcoma, and leukemia. More particular examples of such cancers include squamous cell cancer, small cell lung cancer, non-small cell lung cancer, adenocarcinoma of the lung, squamous carcinoma of the lung, bile duct cancer (e.g., cholangiocarcinoma), esophageal cancer, nasopharyngeal cancer, cancer of the peritoneum, hepatocellular cancer (e.g., hepatocellular carcinoma), gastrointestinal cancer, pancreatic cancer, glioblastoma, cervical cancer, ovarian cancer, liver cancer, bladder cancer, hepatoma, breast cancer, osteosarcoma, skin cancer (e.g., melanoma), colon cancer, colorectal cancer, endometrial or uterine cancer, ovarian cancer, salivary gland carcinoma, kidney cancer, liver cancer, prostate cancer, vulval cancer, thyroid cancer, hepatic carcinoma, and various types of head and neck cancers.

[0159] The terms “cancer cell” and “tumor cell” refer to individual cells or the total population of cells derived from a tumor, 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 tothose tumor cells lacking the capacity to renew and differentiate to distinguish those tumor cells from cancer stem cells.

[0160] The term “chemotherapeutic agent” or “anti-cancer agent” is used herein to refer to a chemical compound that is effective in treating cancer regardless of mechanism of action. Inhibition of metastasis or angiogenesis is frequently a property of a chemotherapeutic agent. Non-limiting examples of chemotherapeutic agents include alkylating agents, for example, nitrogen mustards, ethyleneimine compounds, and alkyl sulphonates; antimetabolites, for example, folic acid, purine or pyrimidine antagonists; anti-mitotic agents, for example, anti-tubulin agents such as eribulin or eribulin mesylate (Halaven™) or derivatives thereof, vinca alkaloids, and auristatins; cytotoxic antibiotics; compounds that damage or interfere with DNA expression or replication, for example, DNA minor groove binders; and growth factor receptor antagonists. In addition, chemotherapeutic agents include antibodies, biological molecules, and small molecules. 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.

[0161] The term “co-administration” or administration “in combination with” one or more therapeutic agents includes concurrent and consecutive administration in any order.

[0162] The term “cytotoxic agent” refers to a substance that causes cell death primarily by interfering with a cell’s expression activity and / or functioning. Examples of cytotoxic agents include, but are not limited to, anti-mitotic agents, such as eribulin, auristatins (e.g., monomethyl auristatin E (MMAE), monomethyl auristatin F (MMAF)), maytansinoids (e.g., maytansine), dolastatins, duostatins, cryptophycins, vinca alkaloids (e.g., vincristine, vinblastine), taxanes, taxols, and colchicines; anthracyclines (e.g., daunorubicin, doxorubicin, dihydroxyanthracindione); cytotoxic antibiotics (e.g., mitomycins, actinomycins, duocarmycins (e.g., CC-1065), auromycins, duomycins, calicheamicins, endomycins, phenomycins); alkylating agents (e.g., cisplatin); intercalating agents (e.g., ethidium bromide); topoisomerase inhibitors (e.g., exactecan, irinotecan, etoposide, tenoposide); radioisotopes, such as At211, 1131, 1125, Y90, Rel86, Rel88, Sml53, Bi212 or 213, P32, and radioactive isotopes of lutetium (e.g., Lu 177); and toxins of bacterial, fungal, plant or animal origin (e.g., ricin (e.g., ricin A-chain), diphtheria toxin, Pseudomonas exotoxin A (e.g., PE40), endotoxin, mitogellin, combrestatin, restrictocin, gelonin, alpha-sarcin, abrin (e.g. , abrin A-chain), modeccin (e.g., modeccin A-chain), curicin, crotin, Sapaonaria officinalis inhibitor, glucocorticoid).

[0163] An “effective amount” of an ADC as disclosed herein is an amount 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 an ADC effective to treat a disease or disorder in a subject. 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. 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.

[0164] 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.

[0165] 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 (1st edition 1988, 2nd 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 TROP2 (e.g., a binding protein comprising CDRs and / or variable domains selected from those identified in Tables 2, 4, and 6), by at least about 50% in the crossblocking 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, e.g., those 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.

[0166] The term “eribulin,” as used herein, refers to a synthetic compound of halichondrin B. The term “eribulin drug moiety” refers to the component of an ADC that has the structure of eribulin, and is attached to the linker of the ADC, e.g., via its C-35 amine. The terms encompass salts thereof. Eribulin is a microtubule dynamics inhibitor, which is thought to bind tubulin and induce cell cycle arrest at the G2 / M phase by inhibiting mitotic spindle assembly. The term “eribulin mesylate” refersto the mesylate salt of eribulin, which is marketed under the trade name Halaven™. Compositions and methods of inhibiting tumor growth in patients comprising administering eribulin are disclosed in U.S. Patent No. 10,322,192, which is incorporated herein by reference in its entirety for all eribulin structures and methods of synthesizing those structures. The structure of eribulin is shown below:

[0167] “Fey receptor,” “Fc-gamma receptor,” or “FcyR” refers to a cell surface protein generally found on immune cells of various types, e.g., neutrophils. The binding of an Fc region of an antibody to a Fey receptor may induce different effector functions, for example antibody-dependent cellular cytotoxicity (ADCC) or antibody-dependent cellular phagocytosis (ADCP), which can have unwanted side effects, for example cell or tissue damage, effector cell activation, or cytokine release. The binding of an Fc region of an antibody to a Fey receptor on a neutrophil may induce cell damage, e.g., neutropenia, through non-antigen-mediated uptake of the antibody.

[0168] The term “homolog” in the context of an antibody or antigen-binding fragment refers to a protein sequence having amino acid residues that are the same or similar at corresponding positions. A homolog may refer to a similar sequence from a different species. Sequence homology, as used herein, refers to a sequence having amino acid residues that are the same or similar at corresponding positions in a reference sequence. Sequence homology may be described by percent identity with a reference sequence. Preferably, sequence homology may be determined by an algorithm such as PILEUP, BLAST, or gapped BLAST, described in further detail below for amino acid sequence identity.

[0169] The terms “IgGl Fc,” “IgGl Fc domain” or “IgGl Fc-containing antibody” as used herein refer to an antibody having at least an IgGl CH2 and CH3 domain, as identified by SEQ ID NO: 164 and SEQ ID NO: 165, respectively.

[0170] “Wild-type IgGl Fc domain” refers to a human IgGl Fc domain that comprises the amino acid sequence of SEQ ID NO: 163 or a fragment thereof.

[0171] 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.

[0172] “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, preferablyinto a degradative compartment in the cell. For example, an internalizing anti-TROP2 antibody is one that is capable of being taken into the cell after binding to TROP2 on the cell membrane.

[0173] The term “KD” refers to the equilibrium dissociation constant of a particular antibodyantigen interaction. KD is calculated by ka / kd. The rate can be determined using standard assays, such as a BIAcore® or ELISA assay.

[0174] 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 BIAcore® or ELISA assay.

[0175] The term “koff” 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 BIAcore® or ELISA assay.

[0176] A “linker” or “linker moiety” is any chemical moiety that is capable of covalently joining a compound, usually a drug moiety such as a chemotherapeutic agent, to another moiety such as an antibody moiety. 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. A “cleavable linker” is any linker that comprises a cleavable moiety and can thus be susceptible to cleavage. A cleavable moiety can be 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.

[0177] The termup” or “antibody: drug ratio” or “drug-to-antibody ratio” or “DAR” refers to the number of drug moieties per antibody moiety, i.e., drug loading, or the number of -L-D moieties per antibody or antigen-binding fragment (Ab) in ADCs of Formula (I). In compositions comprising multiple copies of ADCs of Formula (I), “p” refers to the average number of -L-D moieties per antibody or antigen-binding fragment, also referred to as average drug loading.

[0178] 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 ingredients) 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.

[0179] 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.

[0180] “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.

[0181] 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 morecovalently 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, e.g., 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.

[0182] 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.

[0183] 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 include a default gap weight of 3.00, a default gap length weight of 0.10, and weighted end gaps.

[0184] 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) Nucleic Acids 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 = 1, overlap fraction = 0.125, word threshold (T) = II. The HSP S and HSP S2 parameters are dynamic values and are established bythe 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.

[0185] An additional useful algorithm is gapped BLAST as reported by Altschul et al. (1993) Nucl. Acids 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.

[0186] Generally, proteins disclosed herein and variants thereof (e.g., variants that retain function of the original protein), including variants of TROP2, variants of tubulin sequences, and variants of antibody variable domains (including individual variant CDRs), have amino acid homology, similarity, or identity of at least 80%, and more typically homologies or identities of at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, and almost 100% or 100%.

[0187] 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 uses 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.

[0188] As used herein, the term “solvent” refers to any liquid in which the product is at least partially soluble (solubility of product > 1 g / L).

[0189] As used herein, the term “isomer” refers to compounds with identical molecular formula but distinct spatial arrangement of atoms or bonds. Isomers include stereoisomers, cis-trans isomers, atropisomers, and tautomers.

[0190] As used herein, the term “stereoisomer” refers to both enantiomers and diastereomers.

[0191] It will be appreciated that certain compounds of this invention may exist as separate stereoisomers or enantiomers and / or mixtures of those stereoisomers or enantiomers. As used in the chemical structures disclosed herein, a “wedge” “hash” bond to a stereogenic atomindicates a chiral center of known absolute stereochemistry (i.e., one stereoisomer). As used herein, a stereogenic atom that is notated with an (7?) or (5) indicates the stereochemical designation of the stereogenic atom under the Cahn-Ingold-Prelog convention. As used in the chemical structures disclosed herein, a(“straight”) bond to a stereogenic atom indicates where there is a mixture (e.g., a racemate or enrichment). As used herein, two(“straight”) bonds to a double-bonded carbon indicates that the double bond possesses the E / Z stereochemistry as drawn.

[0192] Certain compounds disclosed herein may exist as tautomers and both tautomeric forms are intended, even though only a single tautomeric structure is depicted.

[0193] 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.

[0194] The term “target-negative” or “target antigen-negative” refers to the absence of target antigen expression by a cell or tissue. The term “target-positive” or “target 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.

[0195] The term “tumor associated calcium signal transducer 2,” “Trop2,” or “TROP2” as used herein, refers to any native form of human TROP2. The term encompasses full-length TROP2 (e.g., NCBI Reference Sequence: NP 002344.2; SEQ ID NO: 161), as well as any form of human TROP2 that results from cellular processing. The term also encompasses naturally occurring variants of TROP2, including but not limited to allelic variants and isoforms. TROP2 can be isolated from a human, or may be produced recombinantly or by synthetic methods.

[0196] 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.

[0197] 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 are the byproducts of an alternative therapeutic modality. As is readily appreciated in the art, full eradication of disease is preferred but not a requirement for a treatment act. “Treatment” or “treat,” as used herein, refers to the administration of a described ADC 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.

[0198] As used herein, “valine-citrulline-pABC,” “Val-Cit-pABC,” and “VCP,” are used interchangeably. As used herein, “valine-alanine-pABC,” “Val-Ala-pABC,” and “VAP” are used interchangeably.

[0199] Should the name of a compound conflict with the structure of the compound anywhere in the present application, the structure supersedes the name and is intended to be controlling.Anti-TROP2 Antibodies and Antigen-Binding Fragments

[0200] The present disclosure provides antibodies that specifically bind to TROP2 and may be used alone, e.g., formulated as therapeutic or diagnostic antibody compositions, e.g., for use in treating or detecting TROP-2 expressing cancers. The antibodies may be provided packaged or prepared for therapeutic use as antibodies, antigen-binding fragments thereof, or as portions of ADCs. Antibodies include, but are not limited to, those listed in Table 1, as well as antibodies comprising CDRs and / or variable domains from the listed antibodies.

[0201] The antibodies disclosed herein may bind to TROP2 with an affinity of ≤ 1 μM, ≤ 100 nM or ≤ 10 nM, or any amount in between, as measured by, e.g., BIAcore® analysis. In certain embodiments, the binding affinity is 1 pM to 500 pM. In some embodiments, the binding affinity is between 500 pM to 1 nM, or 1 nM to 10 nM.

[0202] In some embodiments, the antibodies are four-chain antibodies (also referred to as an immunoglobulin), comprising two heavy chains and two light chains. In some embodiments, the antibodies are two-chain half bodies (one light chain and one heavy chain), or antigen-binding fragments of an immunoglobulin.

[0203] Any antibody or antigen-binding fragment described herein may comprise part of a bispecific or multi-specific binding construct, e.g., a construct that can bind to at least one different antigen or additional epitope on TROP2.

[0204] In some embodiments, the antibodies are internalizing antibodies or internalizing antigenbinding fragments thereof. In some embodiments, the internalizing antibodies bind to TROP2 expressed on the surface of a cell and enter the cell upon or after binding. In some embodiments, the drug moiety of the ADC is released from the antibody moiety of the ADC after the ADC enters and is present in a cell expressing TROP2 (i.e., after the ADC has been internalized).

[0205] The antibodies disclosed herein that specifically bind a TROP2 protein may comprise three heavy chain CDRs (HCDR1, HCDR2, and HCDR3) having amino acid sequences selected from the HC CDRs listed in Table 2, infra, as defined by the Kabat numbering system, and three light chain CDRs (LCDR1, LCDR2, and LCDR3) having amino acid sequences selected from the LC CDRs listed in Table 2, infra, as defined by the Kabat numbering system. In some embodiments, the antibodies comprise three heavy chain CDRs (HCDR1, HCDR2, and HCDR3) having amino acid sequences selected from the HC CDRs listed in Table 4, infra, as defined by the IMGT numbering system, and three light chain CDRs (LCDR1, LCDR2, and LCDR3) having amino acid sequences selected from the LC CDRs listed in Table 4, infra, as defined by the IMGT numbering system.

[0206] In some embodiments, an antibody disclosed herein comprises a VH domain having an amino acid sequence selected from SEQ ID NOs: 53 to 56, 67 to 70, 79 to 83, 168, 174, 175, and 177 listed in Table 6, infra. In some embodiments, the antibody comprises a VL domain having an amino acid sequence selected from SEQ ID NOs: 57 to 66, 71 to 78, 84 to 93, 166, 167, 176, and 187 listed in Table 6, infra.

[0207] In some embodiments, an antigen-binding fragment disclosed herein retains TROP2 binding. In some embodiments, the antigen-binding fragment retains TROP2 binding by comprising three heavy chain CDRs (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences selected from the HC CDRs listed in Table 2, infra, as defined by the Kabat numbering system, and three light chain CDRs (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences selected from the LC CDRs listed in Table 2, infra, as defined by the Kabat numbering system. In some embodiments, the antigen-binding fragment comprises three heavy chain CDRs (HCDR1, HCDR2, and HCDR3)comprising amino acid sequences selected from the HC CDRs listed in Table 4, infra, as defined by the IMGT numbering system, and three light chain CDRs (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences selected from the LC CDRs listed in Table 4, infra, as defined by the IMGT numbering system. In some embodiments, the antigen-binding fragments disclosed herein may retain TROP2 binding by comprising a VH domain comprising an amino acid sequence selected from SEQ ID NOs: 53 to 56, 67 to 70, 79 to 83, 168, 174, 175, and 177 listed in Table 6, infra, and a VL domain comprising an amino acid sequence selected from SEQ ID NOs: 57 to 66, 71 to 78, 84 to 93, 166, 167, 176, and 187 listed in Table 6, infra.

[0208] In some embodiments, the antibodies disclosed herein may comprise an IgG constant domain, e.g., an IgGl domain or an IgGl domain that has been modified to reduce binding to an Fc receptor, e.g., an Fey receptor (FcyR) as compared to a wild-type constant domain-containing (e.g., a wild-type IgGl-containing) antibody. Reduced binding to an Fc receptor, e.g., to an FcyR, can be measured as a comparison to the binding of the wild-type antibody without the modification to the same receptor. Reduced binding may be by at least about 10-fold, and preferably at least about 100- fold as compared to the antibody containing the wild-type constant domain. Reduced binding may be measured using any assay known in the art. For example, reduced binding may be measured using a fluorescence resonance energy transfer (FRET) assay.

[0209] In some embodiments, an antibody disclosed herein may comprise an IgGl comprising the mutations L234A, L235A, P238S, H268Q, and / or K274Q (e.g., comprising all of those mutations) according to the EU numbering. See, e.g., Wang et al. (2017) Protein Cell 9(l):63-73; Vafa et al. (2014) Methods 1; 65(1): 114-26; Tam et al. (2017) Antibodies 1; 6(3):12. Without being bound by theory, these mutations may reduce binding of the antibody to a Fey receptor (FcyR), which may reduce non-antigen mediated uptake of antibodies or ADCs by immune cells, such as neutrophils, thus reducing neutropenia. Reduced neutropenia may be measured using any assay known in the art. For example, reduced neutropenia may be measured using a flow cytometry assay, as illustrated in the Examples provided herein.

[0210] In some embodiments, an antibody that specifically binds a TROP2 protein comprises a heavy chain having an amino acid sequence selected from SEQ ID NOs: 94 to 105, 116 to 127, 136 to 150, 171 to 173, 178 to 186, 380, and 381 listed in Table 8, infra. In some embodiments, an antibody that specifically binds a TROP2 protein comprises a light chain having an amino acid sequence selected from SEQ ID NOs: 106 to 115, 128 to 135, 151 to 160, 169, 170, 188, and 189 listed in Table 8, infra.

[0211] Amino acid and nucleic acid sequences of exemplary antibodies of the present disclosure are set forth in Tables 1-9.Table 1. Antibodies

[0212] In some embodiments, the antibodies listed in Table 1 are humanized by replacing the rabbitspecific framework regions with human-specific framework regions. In some embodiments, a variant of a humanized antibody comprises three heavy chain CDRs (HCDR1, HCDR2, and HCDR3) selected from the CDR sequences listed in Table 2, infra, according to the Kabat system. For example, a humanized variant of 16K21 may comprise three heavy chain CDRs, wherein the HCDR1 comprises SEQ ID NO: 1, the HCDR2 comprises SEQ ID NO: 2 or SEQ ID NO: 3, and the HCDR3 comprises SEQ ID NO: 4. In some embodiments, a variant of a humanized antibody comprises three light chain CDRs (LCDR1, LCDR2, and LCDR3) selected from the CDR sequences listed in Table 2, infra, according to the Kabat system. For example, a humanized variant of 16K21 may comprise threelight chain CDRs, wherein the LCDR1 comprises SEQ ID NO: 5, 6, 7, or 8, the LCDR2 comprises SEQ ID NO: 9, and the LCDR3 comprises SEQ ID NO: 10.

[0213] In some embodiments, a variant of a humanized antibody comprises three heavy chain CDRs (HCDR1, HCDR2, and HCDR3) selected from the CDR sequences listed in Table 4, infra, according to the IMGT system. For example, a humanized variant of 16K21 may comprise three heavy chain CDRs, wherein the HCDR1 comprises SEQ ID NO: 11, the HCDR2 comprises SEQ ID NO: 12, and the HCDR3 comprises SEQ ID NO: 13. In some embodiments, a variant of a humanized antibody comprises three light chain CDRs (LCDR1, LCDR2, and LCDR3) selected from the CDR sequences listed in Table 4, infra, according to the IMGT system. For example, a humanized variant of 16K21 may comprise three light chain CDRs, wherein the LCDR1 comprises SEQ ID NO: 14 or 15, the LCDR2 comprises SEQ ID NO: 16, and the LCDR3 comprises SEQ ID NO: 17.Table 2. Amino acid sequences of inAb Kabat CDRsTable 3. Nucleic acid sequences encoding mAb Kabat CDRsTable 4. Amino acid sequences of mAb IMGT CDRsTable 5. Nucleic acid sequences encoding mAb IMGT CDRsTable 6. Amino acid sequences of mAb variable regionsTable 7. Nucleic acid sequences encoding mAb variable regionsTable 8. Amino acid sequences of full-length mAb Ig chainsTable 9. Nucleic acid sequences of full-length mAb Ig chains

[0214] In some embodiments, the sequences of the heavy chain variable domains, light chain variable domains, full-length heavy chains, and full-length light chains may be “mixed and matched” to create variants of the anti-TROP2 antibodies, e.g., 16K21, 17124, or 20E16. Such “mixed and matched” anti-TROP2 antibodies can be tested using binding assays known in the art (e.g., ELISAs and other assays described in the Examples). For example, an amino acid sequence corresponding to a heavy chain variable domain from a particular set of heavy chain variable domains listed above in Table 6 for a specific antibody may be replaced with another amino acid sequence corresponding to a heavy chain variable domain option from the table. For example, the amino acid sequence of SEQ ID NO: 53 may be replaced with the amino acid sequence of SEQ ID NO: 54 to create a variant of 16K21. Similarly, the amino acid sequence of SEQ ID NO: 57 may be replaced with the amino acid sequence of SEQ ID NO: 62 to create another variant of 16K21 that comprises a RESPECT-L site. The same applies to the mixing and matching of light chain variable domains, full-length heavychains, and full-length light chains. In various embodiments, the antibodies disclosed herein may comprise any set of heavy and light chain variable domains listed in the tables above (e.g., 16K21 heavy and light chain variable domains, 17124 heavy and light chain variable domains, or 20E16 heavy and light chain variable domains), or the set of six CDR sequences from the heavy and light chain set (e.g., three 16K21 heavy chain CDRs and three 16K21 light chain CDRs, three 17124 heavy chain CDRs and three 17124 light chain CDRs, or three 20E16 heavy chain CDRs and three 20E16 light chain CDRs). In some embodiments, the antibodies further comprise human heavy and light chain constant domains or fragments thereof. In various embodiments, the antibodies may comprise any set of full-length heavy chain and full-length light chain sequences listed in the tables above (e.g., 16K21 full-length heavy and light chains, 17124 full-length heavy and light chains, or 20E16 full- length heavy and light chains). In some embodiments, the antibodies may comprise a human IgG heavy chain constant domain and a human kappa light chain constant domain. In some embodiments, the antibodies may comprise a human IgGl, IgG2, IgG3, or IgG4 heavy chain constant domain. In various embodiments, an antibody of the present invention comprises a human immunoglobulin G subtype 1 (IgGl) heavy chain constant domain with a human Ig kappa light chain constant domain. In some embodiments, the constant domain is a modified version of a human constant domain, e.g., comprising one or more of L234A, L235A, P238S, H268Q, and / or K274Q modifications of a human IgGl heavy chain constant domain.

[0215] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 18, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 20, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 21; light chain CDR1 (LCDR1) comprising SEQ ID NO: 22, light chain CDR2 (LCDR2) comprising SEQ ID NO: 24, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 26, as defined by the Kabat numbering system.

[0216] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 18, HCDR2 comprising SEQ ID NO: 20, HCDR3 comprising SEQ ID NO: 21; LCDR1 comprising SEQ ID NO: 23, LCDR2 comprising SEQ ID NO: 24, and LCDR3 comprising SEQ ID NO: 26, as defined by the Kabat numbering system.

[0217] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 27, HCDR2 comprising SEQ ID NO: 28, HCDR3 comprising SEQ ID NO: 29; LCDR1 comprising SEQ ID NO: 30, LCDR2 comprising SEQ ID NO: 31, and LCDR3 comprising SEQ ID NO: 33, as defined by the IMGT numbering system.

[0218] In other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 1, HCDR2 comprising SEQ ID NO: 3, HCDR3 comprising SEQ ID NO: 4; LCDR1comprising SEQ ID NO: 5, LCDR2 comprising SEQ ID NO: 9, and LCDR3 comprising SEQ ID NO: 10, as defined by the Kabat numbering system.

[0219] In other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 1, HCDR2 comprising SEQ ID NO: 3, HCDR3 comprising SEQ ID NO: 4; LCDR1 comprising SEQ ID NO: 8, LCDR2 comprising SEQ ID NO: 9, and LCDR3 comprising SEQ ID NO: 10, as defined by the Kabat numbering system.

[0220] In other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 11, HCDR2 comprising SEQ ID NO: 12, HCDR3 comprising SEQ ID NO: 13; LCDR1 comprising SEQ ID NO: 14, LCDR2 comprising SEQ ID NO: 16, and LCDR3 comprising SEQ ID NO: 17, as defined by the IMGT numbering system.

[0221] In other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 11 , HCDR2 comprising SEQ ID NO: 12, HCDR3 comprising SEQ ID NO: 13; LCDR1 comprising SEQ ID NO: 15, LCDR2 comprising SEQ ID NO: 16, and LCDR3 comprising SEQ ID NO: 17, as defined by the IMGT numbering system.

[0222] In yet other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 34, HCDR2 comprising SEQ ID NO: 37, HCDR3 comprising SEQ ID NO: 38; LCDR1 comprising SEQ ID NO: 39, LCDR2 comprising SEQ ID NO: 41, and LCDR3 comprising SEQ ID NO: 43, as defined by the Kabat numbering system.

[0223] In yet other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three fight chain CDRs as follows: HCDR1 comprising SEQ ID NO: 34, HCDR2 comprising SEQ ID NO: 37, HCDR3 comprising SEQ ID NO: 38; LCDR1 comprising SEQ ID NO: 40, LCDR2 comprising SEQ ID NO: 42, and LCDR3 comprising SEQ ID NO: 43, as defined by the Kabat numbering system.

[0224] In yet other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 44, HCDR2 comprising SEQ ID NO: 46, HCDR3 comprising SEQ ID NO: 47; LCDR1 comprising SEQ ID NO: 50, LCDR2 comprising SEQ ID NO: 51, and LCDR3 comprising SEQ ID NO: 52, as defined by the IMGT numbering system.

[0225] In yet other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 44, HCDR2 comprising SEQ ID NO: 46, HCDR3 comprising SEQ ID NO: 48; LCDR1 comprising SEQ ID NO: 50, LCDR2 comprising SEQ ID NO: 51, and LCDR3 comprising SEQ ID NO: 52, as defined by the IMGT numbering system.

[0226] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO:69, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 72; or a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 76; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 73; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 77; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 72; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO:70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 76; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 73; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 77; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 177, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 72; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 177, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 76; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 177, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 73; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 177, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 77.

[0227] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region amino acid sequence that is at least 95% identical to the above-mentioned heavy chain variable region amino acid sequences and a light chain variable region amino acid sequence that is at least 95% identical to the above-mentioned light chain variable region amino acid sequences. In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof comprises 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: 69 or 70 and 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: 72, 73, 76, or 77.

[0228] In other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 58; or a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63; or a heavy chain variableregion comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61 ; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61 ; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61 ; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region amino acid sequence that is at least 95% identical to the above-mentioned heavy chain variable region amino acid sequences and a light chain variable region amino acid sequence that is at least 95% identical to the above-mentioned light chain variable region amino acid sequences. In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof comprises 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: 55, 56, or 175 and 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: 58, 61, 63, or 66.

[0229] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0230] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63.

[0231] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0232] In yet other embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 80, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 85; or a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 80, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 90; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 80, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 88; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 80, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 93; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 82, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 85; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 82, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 90; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 82, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 88; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 82, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 93. In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region amino acid sequence that is at least 95% identical to the above-mentioned heavy chain variable region amino acid sequences and a light chain variable region amino acid sequence that is at least 95% identical to the above-mentioned light chain variable region amino acid sequences. In some embodiments, an anti- TROP2 antibody or antigen-binding fragment thereof comprises 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: 80 or 82 and 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: 85, 88, 90, or 93.

[0233] In various embodiments, any of the anti-TROP2 antibodies disclosed herein may comprise a human IgGl Fc domain. In some embodiments, an anti-TROP2 antibody comprises a human IgGl Fc domain that is modified to reduce binding to a FcyR as compared to an IgGl Fc-containing antibody with a wild-type IgGl Fc domain. In some embodiments, the anti-TROP2 antibodies comprise a mutated human IgGl Fc domain that comprises one or more (e.g., all of) L234A, L235A, P238S, H268Q, and K274Q modifications to a human IgGl heavy chain constant domain.

[0234] In various embodiments, the anti-TROP2 antibodies comprise a human Ig kappa light chain constant region. In various embodiments, the anti-TROP2 antibodies comprise a human Ig lambda light chain constant region.

[0235] In some embodiments, an anti-TROP2 antibody provided herein comprises a heavy chain comprising an amino acid sequence selected from SEQ ID NO: 118, 119, 122, 123, 126, 127, 184, 185, 186, or 381, and a light chain comprising an amino acid sequence selected from SEQ ID NO: 129, 130, 133, or 134.

[0236] In some embodiments, an anti-TROP2 antibody provided herein comprises a heavy chain comprising an amino acid sequence selected from SEQ ID NO: 96, 97, 100, 101, 104, 105, 179, 181, 183, or 380, and a light chain comprising an amino acid sequence selected from SEQ ID NO: 107, 110, 112, or 115.

[0237] In some embodiments, an anti-TROP2 antibody provided herein comprises a heavy chain comprising an amino acid sequence selected from SEQ ID NO: 137, 139, 142, 144, 147, or 149, and a light chain comprising an amino acid sequence selected from SEQ ID NO: 152, 155, 157, or 160.

[0238] In some embodiments, an anti-TROP2 antibody comprises the heavy chain amino acid sequence of SEQ ID NO: 126 and the light chain amino acid sequence of SEQ ID NO: 129; or the heavy chain amino acid sequence of SEQ ID NO: 122 and the light chain amino acid sequence of SEQ ID NO: 133; or the heavy chain amino acid sequence of SEQ ID NO: 126 and the light chain amino acid sequence of SEQ ID NO: 130; or the heavy chain amino acid sequence of SEQ ID NO:122 and the light chain amino acid sequence of SEQ ID NO: 134; or the heavy chain amino acid sequence of SEQ ID NO: 127 and the light chain amino acid sequence of SEQ ID NO: 129; or the heavy chain amino acid sequence of SEQ ID NO: 123 and the light chain amino acid sequence of SEQ ID NO: 133; or the heavy chain amino acid sequence of SEQ ID NO: 127 and the light chain amino acid sequence of SEQ ID NO: 130; or the heavy chain amino acid sequence of SEQ ID NO:123 and the light chain amino acid sequence of SEQ ID NO: 134; or the heavy chain amino acid sequence of SEQ ID NO: 186 and the light chain amino acid sequence of SEQ ID NO: 129; or the heavy chain amino acid sequence of SEQ ID NO: 185 and the light chain amino acid sequence of SEQ ID NO: 133; or the heavy chain amino acid sequence of SEQ ID NO: 186 and the light chain amino acid sequence of SEQ ID NO: 130; or the heavy chain amino acid sequence of SEQ ID NO: 185 and the light chain amino acid sequence of SEQ ID NO: 134; or the heavy chain amino acid sequence of SEQ ID NO: 381 and the light chain amino acid sequence of SEQ ID NO: 129; or the heavy chain amino acid sequence of SEQ ID NO: 381 and the light chain amino acid sequence of SEQ ID NO: 133; or the heavy chain amino acid sequence of SEQ ID NO: 381 and the light chain amino acid sequence of SEQ ID NO: 130; or the heavy chain amino acid sequence of SEQ ID NO: 381 and the light chain amino acid sequence of SEQ ID NO: 134. In some embodiments, an anti- TROP2 antibody comprises a heavy chain amino acid sequence that is at least 95% identical to one of the above-mentioned heavy chain amino acid sequences and a light chain amino acid sequence that isat least 95% identical to one of the above-mentioned light chain amino acid sequences. In some embodiments, an anti-TROP2 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: 126,127, 186, or 381 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: 129 or 130. In some embodiments, an anti-TROP2 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: 122,123, 185, or 381 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: 133 or 134.

[0239] In some embodiments, an anti-TROP2 antibody comprises the heavy chain amino acid sequence of SEQ ID NO: 104 and the light chain amino acid sequence of SEQ ID NO: 107; or the heavy chain amino acid sequence of SEQ ID NO: 104 and the light chain amino acid sequence of SEQ ID NO: 110; or the heavy chain amino acid sequence of SEQ ID NO: 105 and the light chain amino acid sequence of SEQ ID NO: 107; or the heavy chain amino acid sequence of SEQ ID NO: 105 and the light chain amino acid sequence of SEQ ID NO: 110; or the heavy chain amino acid sequence of SEQ ID NO: 183 and the light chain amino acid sequence of SEQ ID NO: 107; or the heavy chain amino acid sequence of SEQ ID NO: 183 and the light chain amino acid sequence of SEQ ID NO: 110; or the heavy chain amino acid sequence of SEQ ID NO: 380 and the light chain amino acid sequence of SEQ ID NO: 107; or the heavy chain amino acid sequence of SEQ ID NO: 380 and the light chain amino acid sequence of SEQ ID NO: 110; or the heavy chain amino acid sequence of SEQ ID NO: 100 and the light chain amino acid sequence of SEQ ID NO: 112; or the heavy chain amino acid sequence of SEQ ID NO: 100 and the light chain amino acid sequence of SEQ ID NO: 115; or the heavy chain amino acid sequence of SEQ ID NO: 101 and the light chain amino acid sequence of SEQ ID NO: 112; or the heavy chain amino acid sequence of SEQ ID NO: 101 and the light chain amino acid sequence of SEQ ID NO: 115; or the heavy chain amino acid sequence of SEQ ID NO: 181 and the light chain amino acid sequence of SEQ ID NO: 112; or the heavy chain amino acid sequence of SEQ ID NO: 181 and the light chain amino acid sequence of SEQ ID NO: 115; or the heavy chain amino acid sequence of SEQ ID NO: 96 and the light chain amino acid sequence of SEQ ID NO: 112; or the heavy chain amino acid sequence of SEQ ID NO: 96 and the light chain amino acid sequence of SEQ ID NO: 115; or the heavy chain amino acid sequence of SEQ ID NO: 97 and the light chain amino acid sequence of SEQ ID NO: 112; or the heavy chain amino acid sequence of SEQ ID NO: 97 and the light chain amino acid sequence of SEQ ID NO: 115; or the heavy chain amino acid sequence of SEQ ID NO: 179 and the light chain amino acid sequence of SEQ ID NO: 112; or the heavy chain amino acid sequence of SEQ ID NO: 179 and the light chain amino acid sequence of SEQ ID NO: 115; or the heavy chain amino acid sequence of SEQ ID NO: 380 and the light chain amino acid sequence of SEQ ID NO: 112; or the heavy chain amino acid sequence of SEQ ID NO: 380 and the light chain amino acid sequence of SEQ ID NO: 115. In some embodiments, an anti-TROP2 antibody comprises a heavy chain amino acid sequence that is at least95% identical to one of the above-mentioned heavy chain amino acid sequences and a light chain amino acid sequence that is at least 95% identical to one of the above-mentioned light chain amino acid sequences. In some embodiments, an anti-TROP2 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: 104, 105, 183, or 380 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: 107 or 110. In some embodiments, an anti-TROP2 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: 100, 101, 181, or 380 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: 112 or 115.

[0240] In some embodiments, the anti-TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti-TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti- TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti-TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 181 and the light chain amino acid sequence of SEQ ID NO: 110. In some embodiments, the anti-TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 183 and the light chain amino acid sequence of SEQ ID NO: 110. In some embodiments, the anti-TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 380 and the light chain amino acid sequence of SEQ ID NO: 110.

[0241] In some embodiments, the anti-TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 100 and a light chain amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti-TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 96 and a light chain amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti- TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 100 and the light chain amino acid sequence of SEQ ID NO: 110. In some embodiments, the anti-TROP2 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 96 and the light chain amino acid sequence of SEQ ID NO: 110.

[0242] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 1, HCDR2 comprising SEQ ID NO: 3, HCDR3 comprising SEQ ID NO: 4; LCDR1 comprising SEQ ID NO: 8, LCDR2 comprising SEQ ID NO: 9, and LCDR3 comprising SEQ ID NO: 10, as defined by the Kabat numbering system. In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 11, HCDR2 comprising SEQ ID NO: 12, HCDR3 comprising SEQ ID NO: 13; LCDR1 comprising SEQ ID NO: 15, LCDR2 comprising SEQ ID NO: 16, and LCDR3 comprising SEQ ID NO: 17, as defined by the IMGT numbering system. Insome embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61 ; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115 ; a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115; or a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115.

[0243] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 1, HCDR2 comprising SEQ ID NO: 3, HCDR3 comprising SEQ ID NO: 4; LCDR1 comprising SEQ ID NO: 8, LCDR2 comprising SEQ ID NO: 9, and LCDR3 comprising SEQ ID NO: 10, as defined by the Rabat numbering system. In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof provided herein comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 11, HCDR2 comprising SEQ ID NO: 12, HCDR3 comprising SEQ ID NO: 13; LCDR1 comprising SEQ ID NO: 15, LCDR2 comprising SEQ ID NO: 16, and LCDR3 comprising SEQ ID NO: 17, as defined by the IMGT numbering system. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61 ; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment comprises a heavy chain amino acid sequence of SEQ ID NO: 100 and a light chain amino acid sequence of SEQ ID NO: 115.

[0244] In some embodiments, the disclosed anti-TROP2 antibodies demonstrate an increased safety profile due to substitution of residues in the Fc domain. In some embodiments, the disclosed anti- TROP2 antibodies comprise an IgGl Fc domain that has been mutated to reduce binding to a Fey receptor (FcyR) as compared to an IgGl Fc-containing antibody with a wild-type IgGl Fc domain. These substitutions reduce the ability of the antibody to bind to various cell receptors, such as a Fey receptor (FcyR), and other immune molecules, as compared to an anti-TROP2 antibody without these substitutions. Without being bound by theory, the reduced binding of an antibody to a FcyR may reduce non-antigen mediated uptake by neutrophils, thereby reducing neutropenia in a treated subject.

[0245] In some embodiments, the disclosed anti-TROP2 antibodies demonstrate superior properties (e.g., improved stability {e.g., shelf and / or serum stability), formulatability, antigen-binding specificity (e.g., epitope and / or affinity), safety profile, in vivo anti-tumor activity) compared to other TROP2 antibodies. In some embodiments, the disclosed anti-TROP2 antibodies demonstrate superiorantigen-binding specificity compared to other TROP2 antibodies. In some embodiments, the disclosed anti-TROP2 antibodies demonstrate superior site-specific linker-payload conjugation compared to other TR0P2 antibodies. In some embodiments, the disclosed anti-TROP2 antibodies demonstrate a superior safety profile in vivo compared to other TR0P2 antibodies.

[0246] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof that comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system, demonstrates superior properties (e.g., improved stability (e.g., shelf and / or serum stability), formulatability, antigen-binding specificity (e.g., epitope and / or affinity), safety profile, in vivo anti-tumor activity, antigen-binding specificity, site-specific linker-payload conjugation, safety profile in vivo) compared to other TROP2 antibodies.

[0247] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof that comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system, demonstrates superior properties (e.g., improved stability (e.g., shelf and / or serum stability), formulatability, antigen-binding specificity (e.g., epitope and / or affinity), safety profile, in vivo anti-tumor activity, antigen-binding specificity, site-specific linkerpayload conjugation, safety profile in vivo) compared to other TROP2 antibodies.

[0248] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof that comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175 and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66 demonstrates superior properties (e.g., improved stability (e.g., shelf and / or serum stability), formulatability, antigen-binding specificity (e.g., epitope and / or affinity), safety profile, in vivo anti-tumor activity, antigen-binding specificity, site-specific linker-payload conjugation, safety profile in vivo) compared to other TROP2 antibodies.

[0249] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof that comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55 and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66 demonstrates superior properties (e.g., improved stability (e.g., shelf and / or serum stability), formulatability, antigen-binding specificity (e.g., epitope and / or affinity), safety profile, in vivo anti-tumor activity, antigen-binding specificity, site-specific linker-payload conjugation, safety profile in vivo) compared to other TROP2 antibodies.

[0250] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof that comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 115 demonstrates superior properties (e.g.,improved stability (e.g., shelf and / or serum stability), formulatability, antigen-binding specificity (e.g., epitope and / or affinity), safety profile, in vivo anti-tumor activity, antigen-binding specificity, site-specific linker-payload conjugation, safety profile in vivo) compared to other TR0P2 antibodies.

[0251] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof that comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 115 demonstrates superior properties (e.g., improved stability (e.g, shelf and / or serum stability), formulatability, antigen-binding specificity (e.g., epitope and / or affinity), safety profile, in vivo anti-tumor activity, antigen-binding specificity, site-specific linker-payload conjugation, safety profile in vivo) compared to other TROP2 antibodies.

[0252] In some embodiments, an anti-TROP2 antibody or antigen-binding fragment thereof that comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 115 demonstrates superior properties (e.g., improved stability (e.g., shelf and / or serum stability), formulatability, antigen-binding specificity (e.g., epitope and / or affinity), safety profile, in vivo anti-tumor activity, antigen-binding specificity, site-specific linker-payload conjugation, safety profile in vivo) compared to other TROP2 antibodies.

[0253] In any of the antibodies discussed above, the heavy chain amino acid sequence may lack the C-terminal lysine.

[0254] In various embodiments, amino acid substitutions may be made while retaining the binding affinity and / or specificity of an antibody disclosed herein and / or to provide one or more additional beneficial property, e.g., by making one or more changes in framework, constant domain, and / or CDR sequences. In some embodiments, the substitutions are of single residues. For instance, in some embodiments, the anti-TROP2 antibodies comprise a human IgGl Fc domain that comprises amino acid substitutions to reduce binding to a FcyR as compared to an IgGl Fc-containing antibody with a wild-type IgGl Fc domain. In some embodiments, the anti-TROP2 antibodies comprise a mutated human IgGl Fc domain that comprises one or more of the substitutions selected from N297Q, N297A, L234G / L235G, L234A / L235A, L234A / L235A / D265S, L234A / L235A / P329G, L234A / L235A / P238S / H268Q / K274Q, L235G / G236R, G236R / L328R, and / or L234S / L235T / G236R. In some embodiments, the anti-TROP2 antibodies comprise a mutated human IgGl Fc domain that comprises the substitutions L234A, L235A, P238S, H268Q, and K274Q. 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 TROP2). 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 10.Table 10. Exemplary Conservative Amino Acid Substitutions

[0255] Substantial changes in function or immunological identity are made by selecting substitutions that are less conservative than those shown in Table 10. 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 are expected to 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.

[0256] 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. For example, the anti-TROP2 antibodies provided herein may comprise a human IgGl Fc domain that is mutated to reduce binding to a FcyR as compared to an IgGl Fc-containing antibody with a wild-type IgGl Fc domain. 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, as discussed herein.

[0257] Various anti-TROP2 antibodies may be used with the ADCs disclosed herein to target cancer cells. As shown below, the linker-toxins in the ADCs disclosed herein are surprisingly effective withthe anti-TR0P2 antibodies also disclosed herein. These antibodies may be used with the linkers and toxin (e.g., eribulin) disclosed herein. In some embodiments, the TROP2-targeting antibody moiety is 17124 or a variant disclosed herein. In other embodiments, the TROP2-targeting antibody moiety is 16K21 or a variant disclosed herein. In yet other embodiments, the TROP2 -targeting antibody moiety is 20E16 or a variant disclosed herein. In some embodiments, while the disclosed linkers and toxin (eribulin) are surprisingly effective with several different TROP2-targeting antibodies, the TROP2 targeting antibody moieties such as 16K21 or a variant disclosed herein provided particularly improved antibody / ADC stability, manufacturability, tumor targeting, treatment efficacy, and reduced off-target killing. Improved treatment efficacy can be measured in vitro or in vivo, and may include reduced tumor growth rate and / or reduced tumor volume.Linkers

[0258] In various embodiments, the anti-TROP2 antibodies and antigen-binding fragments disclosed herein may be joined to a drug moiety (e.g., a cytotoxic payload) by a linker to create an antibodydrug conjugate (ADC).

[0259] In some 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 moiety remains attached to the drug moiety (e.g., eribulin). 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 when evaluated over a set period of time. In some embodiments, the linkers in ADCs disclosed herein are chosen to remain stable 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.

[0260] 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, or 24 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, 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 moiety can bind to its target (e.g., to microtubules). Thus, an effective linker will: (i) maintain the specific binding properties of the antibody moiety; (ii) allow delivery, e.g., intracellular delivery, of the drug moiety via stable attachment to the antibody moiety;(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.

[0261] Linkers may impact the physico-chemical properties of an ADC. As many cytotoxic agents are hydrophobic in nature, Unking 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 biologies, 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. In various embodiments, a linker is conjugated to the antibody or antigen-binding fragment through a cysteine. In various embodiments, a linker is conjugated to the antibody or antigen-binding fragment through a lysine. Suitable methods for conjugating linkers of the present disclosure to an antibody include the technologies for directed attachment to a lysine on a heavy chain of an antibody and to a cysteine on the light chain of an antibody, e.g., as disclosed in PCT applications WO 2017 / 213267, WO 2017 / 106643, and WO 2016 / 205618, all of which are herein incorporated by reference in their entireties.

[0262] In some embodiments, the linker is a cleavable linker. Cleavable linkers are designed to release the drug when subjected to certain environmental factors, e.g., when internalized into the target cell. 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 drug moiety from the ADC via cleavage at a particular site in the linker.

[0263] In some embodiments, the linker is cleavable under intracellular conditions, such that cleavage of the linker sufficiently releases the drug moiety from the antibody moiety in the intracellular environment to activate the drug and / or render the drug therapeutically effective. In some embodiments, the drug moiety is not cleaved from the antibody moiety until the ADC enters a cell that expresses an antigen specific for the antibody moiety of the ADC, and the drug moiety is cleaved from the antibody moiety 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 moiety remains bound to the drug moiety upon cleavage. Exemplary cleavable linkers include acid labile linkers, protease / peptidase-sensitive linkers, photolabile linkers, dimethyl-, disulfide-, or sulfonamide- containing linkers.

[0264] 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 caveolea). 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. In some embodiments, the linker is acleavable 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. In some embodiments, a cleavable peptide linker is more stably conjugated to an antibody disclosed herein compared to an acid labile linker.

[0265] 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 or legumain (also known as asparaginyl endopeptidase or vacuolar processing enzyme). In some embodiments, the linker is a cathepsin- cleavable linker. In some embodiments, the linker is a legumain-cleavable linker. In some embodiments, the linker is a plasmin-cleavable tinker. In some embodiments, the cleavable peptide moiety in the tinker is cleavable by a lysosomal cysteine cathepsin, such as cathepsin B, C, F, H, K, L, O, S, V, X, or W. In some 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. Another exemplary dipeptide that may be cleaved by cathepsin B is valine-alanine (Val-Ala). Fu and Ho (2002) Antib. Ther. 1 (2):33-43. In some embodiments, a dipeptide that may be cleaved by cathepsin B comprises at least one methyl group, e.g., two methyl groups. An exemplary dipeptide comprising two methyl groups that may be cleaved by cathepsin B is valine-dimethylated lysine (Val-Lys(Me)2). Another exemplary dipeptide comprising two methyl groups that may be cleaved by cathepsin B is alanine-dimethylated lysine (Ala-Lys(Me)2).

[0266] In some embodiments, the cleavable peptide moiety in the linker is cleavable by a lysosomal cysteine endopeptidase, such as legumain. An exemplary monopeptide that may be cleaved by legumain is asparagine (Asn). Another exemplary monopeptide that may be cleaved by legumain is aspartic acid (Asp). In some embodiments, a cleavable monopeptide that is cleaved by legumain comprises a methyl group, e.g., methylated aspartic acid (Asp(OMe)).

[0267] In some embodiments, a cleavable peptide moiety cleavable by legumain may be referred to as “DTM-N” (dithiomaleimide-Asn) and have the structure as shown below:

[0268] In some embodiments, the cleavable peptide moiety in the linker is cleavable by a serine protease, such as plasmin. In some embodiments, a peptide that may be cleaved by plasmin may comprise phenylalanine-lysine (Phe-Lys).

[0269] 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 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, monopeptides, dipeptides, tripeptides, tetrapeptides, and pentapeptides. Exemplary monopeptides include, but are not limited to, asparagine (Asn) and aspartic acid (Asp). Exemplary dipeptides include, but are not limited to, valine-citrulline (Val-Cit), alanine-asparagine (Ala-Asn), alanine-phenylalanine (Ala-Phe), phenylalanine-lysine (Phe-Lys), alanine-lysine (Ala-Lys), alanine-valine (Ala-Vai), valine-alanine (Vai- Ala), valine-lysine (Val-Lys), lysine-lysine (Lys-Lys), phenylalanine-citrulline (Phe-Cit), leucine-citrulline (Leu-Cit), isoleucinecitrulline (Ile-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), glutamic acid-valine -citrulline, glycine-glycine-glycine (Gly-Gly-Gly), phenylalanine-phenylalanine-lysine (Phe-Phe-Lys), alanine-phenylalanine-lysine (Ala-Phe-Lys), and glycine-phenylalanine-lysine (Gly-Phe-Lys). Exemplary tetrapeptides include, but are not limited to, glycine-glycine-phenylalanine-glycine (Gly-Gly-Phe-Gly). Other exemplary amino acid units include, but are not limited to, Gly-Phe-Leu-Gly, Ala-Leu-Ala-Leu, Phe-N9-tosyl-Arg, and Phe-N9-Nitro-Arg, as described in, e.g., U.S. Pat. No. 6,214,345. In some embodiments, an amino acid unit comprises amino acid residues comprising at least one methyl group, e.g., a monomethyl or dimethyl group. Exemplary amino acid units that comprise amino acid residues comprising at least one methyl group include, but are not limited to, methylated aspartic acid (Asp(OMe)), alanine-dimethylated lysine (Ala-Lys(Me)2), and valine-dimethylated lysine (Val-Lys(Me)2). In some embodiments, the amino acid unit in the linker comprises Val-Cit. In some embodiments, the amino acid unit in the linker comprises Val-Ala. An amino acid unit may comprise amino acid residues that occur naturally and / or minor amino acids and / or non-naturally occurring amino acids, 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 legumain.

[0270] In some embodiments, the linker in an ADC disclosed herein may comprise an antibody attachment moiety. An antibody attachment moiety may be used, for example, to link the antibody moiety to the linker, which in turn may link to the drug moiety, e.g., indirectly through a cleavable moiety (e.g., a cleavable peptide).

[0271] In some embodiments, the linker comprises an antibody attachment moiety comprising a maleimide moiety (Mai). The term “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 moiety. Other functional groups that are reactive with sulfhydryl groups (thiols) and may therefore be used in place of a Mai include, but are not limited to,iodoacetamide, bromoacetamide, vinyl pyridine, disulfide, pyridyl disulfide, isocyanate, and isothiocyanate.

[0272] In some embodiments, the linker attaches to the antibody or antigen-binding fragment via a Mai moiety. In some embodiments, the Mai moiety is reactive with a cysteine residue on the antibody or antigen-binding fragment. In some embodiments, the Mai moiety is joined to the antibody or antigen-binding fragment via the cysteine residue.

[0273] In some embodiments, the Mai moiety comprises at least one, e.g., two or more, sulfidereactive groups. In some embodiments, the Mai moiety is reactive with two adjacent reduced cysteine residues on the antibody or antigen-binding fragment. In some embodiments, the Mai moiety is joined to the antibody or antigen-binding fragment via two cysteine residues.

[0274] In some embodiments, the Mai moiety comprises a maleimidocaproyl (MC) moiety. In some embodiments, the linker attaches to the antibody or antigen-binding fragment via an MC moiety. In some embodiments, the MC moiety is reactive with a cysteine residue on the antibody or antigenbinding fragment. In some embodiments, the MC moiety is joined to the antibody or antigen-binding fragment via the cysteine residue.

[0275] In some embodiments, the Mai moiety comprises a dithiomaleimide (DTM). In some embodiments, the linker attaches to the antibody or antigen-binding fragment via a DTM moiety. In some embodiments, the DTM moiety is reactive with a cysteine residue on the antibody or antigenbinding fragment. In some embodiments, the DTM moiety is joined to the antibody or antigenbinding fragment via the cysteine residue.

[0276] In some embodiments, the linker comprises the Mai moiety and a cleavable peptide moiety. In some embodiments, the Mai moiety attaches the antibody moiety to the cleavable peptide moiety in the linker. 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-Lys(Me)2. In some embodiments, the amino acid unit comprises Val-Ala. In some embodiments, the amino acid unit comprises Asn. In some embodiments, the amino acid unit comprises Asp. In some embodiments, the amino acid unit comprises Asp(OMe). In some embodiments, the amino acid unit comprises Ala-Lys(Me)2. In some embodiments, the linker comprises Mal-Val-Cit. In some embodiments, the linker comprises Mal-Val-Lys(Me)2. In some embodiments, the linker comprises Mal-Val-Ala. In some embodiments, the linker comprises Mal- Asn. In some embodiments, the linker comprises Mal-Asp. In some embodiments, the linker comprises Mal-Asp(OMe). In some embodiments, the linker comprises Mal-Ala-Lys(Me)2.

[0277] In some embodiments, any of the linkers in ADCs disclosed herein may comprise at least one spacer unit joining the antibody moiety to the drug moiety. In some embodiments, the spacer unit joins a cleavage site (e.g., a cleavable peptide moiety) in the linker to the antibody moiety. In some embodiments, the spacer unit joins a cleavage site (e.g., a cleavable peptide moiety) in the linker to the drug moiety. In some embodiments, the linker, and / or spacer unit in the linker, is substantiallyhydrophilic. 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, the linker includes one or more polyethylene glycol (PEG) moieties, e.g., 1, 2, 3, or 4 PEG moieties.

[0278] In some embodiments, the spacer unit in the linker comprises one or more PEG moieties. In some embodiments, the spacer unit comprises -(PEG)m-, and m is an integer from 1 to 4. In some embodiments, m ranges from 1 to 4; or from 2 to 4. In some embodiments, m is 1. In some embodiments, m is 2. In some embodiments, m is 3. In some embodiments, m is 4. In some embodiments, the spacer unit comprises (PEG)1, (PEG)2, (PEG)3, or (PEG)4. In some embodiments, the spacer unit comprises (PEG)2.

[0279] In some embodiments, the spacer unit in the linker comprises an alkyl moiety. In some embodiments, the spacer unit comprises -(CH2)n-, and n is an integer from 1 to 10 (i.e., n may be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10). In some embodiments, n is an integer from 1 to 6. In some embodiments, n is 1, 2, 3, 4, 5, or 6. In some embodiments, the spacer unit comprises -CH2-CH2-.

[0280] In some embodiments, the spacer unit comprises(“C2”).

[0281] In some embodiments, the spacer unit comprises(C2) and -(PEG)m-, and m is an integer from 1 to 4. In some embodiments, the spacer unit comprisesconjugated to -(PEG)m-, and m is an integer from 1 to 4. In some embodiments, m ranges from 1 to 4; from 2 to 4; or from 1 to 3. In some embodiments, m is 1. In some embodiments, m is 2. In some embodiments, m is 3. In some embodiments, m is 4.

[0282] In some embodiments, the spacer unit comprises(C2) conjugated to (PEG)2.

[0283] In some embodiments, the spacer unit comprises(“C2(PEG)m”), wherein m is 0-3. In some embodiments, m is 0. In some embodiments, m is 1. In some embodiments, m is 2. In some embodiments, m is 3.

[0284] In some embodiments, the spacer unit comprises(“C2(PEG)2”).

[0285] In some embodiments, using a linker comprising a spacer unit comprising C2may provide benefits over other linkers when conjugated to any of a variety of different antibodies or antigen-binding fragments. In some embodiments, a linker comprising C2conjugated to -(PEG)m-, wherein m is an integer from 0 to 4 (e.g., (PEG)1, (PEG)2, or (PEG)3) demonstrates superior properties when conjugated to any of a variety of different antibodies or antigen-binding fragments. In some embodiments, the spacer unit comprising C2is or comprises C2(PEG)m, wherein m is 0-3. In some embodiments, using a linker comprising a spacer unit comprising C2(PEG)m, wherein m is 0-3, may provide benefits, as compared to alternative linkers not comprising a unit of C2(PEG)m, wherein m is 0-3, when conjugated to any of a variety of different antibodies or antigen-binding fragments. These benefits may include, e.g., improved conjugation stability, improved plasma stability, and / or in vivo anti-tumor activity compared to other linkers comprising alternative spacer units. In some embodiments, without being bound by theory, benefits of using a linker comprising C2(PEG)m, wherein m is 0-3, conjugated to eribulin may include improved conjugation stability, improved plasma stability, and / or in vivo anti-tumor activity. In some embodiments, a linker comprising C2(PEG)m, wherein m is 0-3, and VCP conjugated to eribulin demonstrates superior properties when conjugated to an anti-TROP2 antibody disclosed herein. In some embodiments, a linker comprising C2(PEG)m, wherein m is 0-3, and N conjugated to eribulin demonstrates superior properties when conjugated to an anti-TROP2 antibody disclosed herein. In some embodiments, m is 2. Exemplary evidence of the superior benefits of such antibody-drug conjugates is shown in Example 7.

[0286] A spacer unit may be used, for example, to link the antibody moiety to the drug moiety, either directly or indirectly. In some embodiments, the spacer unit links the antibody moiety to the drug moiety directly. In some embodiments, the antibody moiety and the drug moiety are attached via a spacer unit comprising one or more PEG moieties (e.g., (PEG)2, (PEG)3, or (PEG)4). In some embodiments, the spacer unit links the antibody moiety to the drug moiety indirectly. In some embodiments, the spacer unit links the antibody moiety to the drug moiety indirectly through a cleavable moiety (e.g., a cleavable peptide) and / or an antibody attachment moiety to join the spacer unit to the antibody moiety, e.g., a maleimide moiety or a carbobenzoxy-L-glutaminyl-glycine moiety.

[0287] In some embodiments, the spacer unit attaches to the antibody moiety (i.e., the antibody or antigen-binding fragment) via a maleimide moiety (Mai). A spacer unit that attaches to the antibody or antigen-binding fragment via a Mai is referred to herein as a “Mal-spacer unit.” In some embodiments, the Mal-spacer unit is reactive with a cysteine residue on the antibody or antigenbinding fragment. In some embodiments, the Mal-spacer unit is joined to the antibody or antigenbinding 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. In some embodiments, the Mal-spacer unit comprises C2. In some embodiments, the Mal-spacer unit comprises C2(PEG)1. In some embodiments, the Mal-spacer unit comprises C2(PEG)2. In some embodiments, the Mal-spacer unit comprises C2(PEG)3.

[0288] 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 someembodiments, the amino acid unit comprises Val-Cit. In some embodiments, the amino acid unit comprises Val-Lys(Me)2. In some embodiments, the amino acid unit comprises Ala-Lys(Me)2. In some embodiments, the amino acid unit comprises Vai-Ala. In some embodiments, the amino acid unit comprises Asn. In some embodiments, the amino acid unit comprises Asp. In some embodiments, the amino acid unit comprises Asp(OMe). In some embodiments, the linker comprises the Mal-spacer unit and an amino acid unit. In some embodiments, the linker comprises Mal-(PEG)mand an amino acid unit, wherein m is 2 to 4; or 2, 3, or 4. In some embodiments, the linker comprises Mal-(PEG)2- Val-Cit. In some embodiments, the linker comprises Mal-(PEG)3-Val-Cit. In some embodiments, the linker comprises Mal-(PEG)4-Val-Cit. In some embodiments, the linker comprises Mal-(PEG)2-Val- Lys(Me)2. In some embodiments, the linker comprises Mal-(PEG)2-Ala-Lys(Me)2. In some embodiments, the linker comprises Mal-(PEG)2-Val-Ala. In some embodiments, the linker comprises Mal-(PEG)2-Asn. In some embodiments, the linker comprises Mal-(PEG)2-Asp. In some embodiments, the linker comprises Mal-(PEG)2-Asp(OMe). In some embodiments, the linker comprises Mal-C2- Val-Cit. In some embodiments, the linker comprises Mal-C2-VCP. In some embodiments, the linker comprises Mal-C2(PEG)1-Val-Cit. In some embodiments, the linker comprises Mal-C2(PEG)1-Val-Lys(Me)2. In some embodiments, the linker comprises Mal-C2(PEG)1- Ala-Lys(Me)2. In some embodiments, the linker comprises Mal-C2(PEG)1-Val-Ala. In some embodiments, the linker comprises Mal-C2(PEG)1-Asn. In some embodiments, the linker comprises Mal-C2(PEG)1-Asp. In some embodiments, the linker comprises Mal-C2(PEG)1-Asp(OMe). In some embodiments, the linker comprises Mal-C2(PEG)2-Val-Cit. In some embodiments, the linker comprises Mal-C2(PEG)2-Val-Lys(Me)2. In some embodiments, the linker comprises Mal-C2(PEG)2- Ala-Lys(Me)2. In some embodiments, the linker comprises Mal-C2(PEG)2-Val-Ala. In some embodiments, the linker comprises Mal-C2(PEG)2-Asn. In some embodiments, the linker comprises Mal-C2(PEG)2-Asp. In some embodiments, the linker comprises Mal-C2(PEG)2-Asp(OMe). In some embodiments, the linker comprises Mal-C2(PEG)3-Val-Cit. In some embodiments, the linker comprises Mal-C2(PEG)3-Val-Lys(Me)2. In some embodiments, the linker comprises Mal-C2(PEG)3- Ala-Lys(Me)2. In some embodiments, the linker comprises Mal-C2(PEG)3-Val-Ala. In some embodiments, the linker comprises Mal-C2(PEG)3-Asn. In some embodiments, the linker comprises Mal-C2(PEG)3-Asp. In some embodiments, the linker comprises Mal-C2(PEG)3-Asp(OMe).

[0289] In various embodiments, the cleavable moiety in the linker is joined directly to the drug moiety and / or to the antibody moiety. In other embodiments, a spacer unit is used to attach the cleavable moiety in the linker to the drug moiety and / or to the antibody moiety. In various embodiments, the drug moiety is eribulin. In various embodiments, the eribulin is attached to the cleavable moiety in the linker by a spacer unit. In some embodiments, the eribulin is attached to the cleavable moiety in the linker by a self-immolative spacer unit. In some embodiments, the eribulin is attached to the cleavable moiety in the linker by a self-immolative spacer unit, the cleavable moiety comprises an amino acid unit, and a further spacer unit comprising PEG joins the cleavable moiety tothe antibody moiety. In some embodiments, the eribulin is attached to the cleavable moiety in the linker by a self-immolative spacer unit, the cleavable moiety comprises an amino acid unit, and a further spacer unit comprising C2(PEG)m, wherein m is 0 to 4 (e.g., C2(PEG)2), joins the cleavable moiety to the antibody moiety. In some embodiments, the eribulin is joined to an anti-TROP2 antibody via a Mal-spacer unit in the linker joined to a cleavable peptide moiety and a pAB or pABC self-immolative spacer unit.

[0290] 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 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 entirely under cellular conditions. A “self-immolative” spacer unit allows for release of the native drug moiety under intracellular conditions. A “native drug” is one where no part of the spacer unit or other chemical modification remains after cleavage / degradation of the spacer unit.

[0291] 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 drug moiety (e.g., eribulin) is self-immolative, and undergoes self-immolation concurrently with or shortly before / after cleavage of the cleavable moiety under intracellular conditions.

[0292] In certain embodiments, the self-immolative spacer unit in the linker comprises a p- aminobenzyl unit. In some embodiments, a p-aminobenzyl alcohol (pAB-OH) 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 pAB-OH 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-aminobenzyl (pAB). In some embodiments, the self-immolative spacer unit is or comprises p-aminobenzyloxycarbonyl (pABC). Without being bound by theory, it is thought that the self-immolation of pAB or pABC involves a spontaneous 1,6-elimination reaction. Jain et al. (2015) Pharm Res 32:3526-40.

[0293] In various embodiments, the structure of the p-aminobenzyl (pAB) used in the disclosed ADCs is shown below:

[0294] In various embodiments, the structure of the p-aminobenzyloxycarbonyl (pABC) used in the disclosed ADCs is shown below:

[0295] In various embodiments, a linker (e.g., one comprising a spacer, e.g., comprising a self- immolative spacer unit) attaches the cleavable moiety in the linker to the C-35 amine on eribulin. In some embodiments, the self-immolative spacer unit comprises pAB. In some embodiments, the pAB attaches the cleavable moiety in the linker to the C-35 amine on eribulin. In some embodiments, the pAB undergoes self-immolation upon cleavage of the cleavable moiety, and eribulin is released from the ADC in its native, active form.

[0296] In some embodiments, the self-immolative spacer unit comprises pABC. In some embodiments, the pABC attaches the cleavable moiety in the linker to the C-35 amine on eribulin. In some embodiments, the pABC undergoes self-immolation upon cleavage of the cleavable moiety, and eribulin is released from the ADC in its native, active form. 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 (VCP). In some embodiments, the amino acid unit is Val-Lys(Me)2. In some embodiments, the linker comprises Val-Lys(Me)2-pABC. In some embodiments, the amino acid unit is Ala-Lys(Me)2. In some embodiments, the linker comprises Ala- Lys(Me)2-pABC. In some embodiments, the amino acid unit is Val-Ala. In some embodiments, the linker comprises Val-Ala-pABC (VAP). In some embodiments, the amino acid unit is Asn. In some embodiments, the linker comprises Asn-pABC. In some embodiments, the amino acid unit is Asp. In some embodiments, the linker comprises Asp-pABC. In some embodiments, the amino acid unit is Asp(OMe). In some embodiments, the linker comprises Asp(OMe)-pABC.

[0297] In various aspects, the antibody moiety of the ADC is conjugated to the drug moiety via a linker, wherein the linker comprises a Mal-spacer unit, a cleavable amino acid unit, and a pAB or a pABC. In some embodiments, the spacer unit comprises a PEG moiety. In some embodiments, the spacer unit comprises an alkyl moiety. In some embodiments, the spacer unit comprises C2. In some embodiments, the spacer unit comprises C2(PEG)1. In some embodiments, the spacer unit comprises C2(PEG)2. In some embodiments, the spacer unit comprises C2(PEG)3. In some embodiments, the linker comprises Mal-(PEG)2-amino acid unit-pABC. In some embodiments, the linker comprises Mal-(PEG)2-Val-Cit-pABC. In some embodiments, the linker comprises Mal-(PEG)3-Val-Cit-pABC. In some embodiments, the linker comprises Mal-(PEG)4-Val-Cit-pABC. In some embodiments, the linker comprises Mal-(PEG)2-Val-Ala-pABC. In some embodiments, the linker comprises Mai-(PEG)2-Val-Lys(Me)2-pABC. In some embodiments, the linker comprises Mal-(PEG)2-Ala-Lys(Me)2- pABC. In some embodiments, the linker comprises Mal-C2(PEG)m-amino acid unit-pABC. In some embodiments, the linker comprises Mal-C2(PEG)m-Val-Cit-pABC. In some embodiments, the linker comprises Mal-C2(PEG)m-Val-Ala-pABC. In some embodiments, the linker comprises Mal- C2(PEG)2-Val-Lys(Me)m-pABC. In some embodiments, m is an integer from 0 to 4. In some embodiments, m is 2.

[0298] In various embodiments, the linker is designed to facilitate bystander killing (the killing of neighboring cells) 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 moiety of an ADC, but surrounds target cancer tissue expressing that antigen. In some embodiments, a linker comprising a maleimide moiety (Mai), a polyethylene glycol (PEG) moiety, valine-citrulline (Val-Cit or “VC”), and a pABC provides these functional features. In some embodiments, a linker comprising a maleimide moiety (Mai), a polyethylene glycol (PEG) moiety, valine-alanine (Val-Ala or “VA”), and a pABC provides these functional features. In some embodiments, a linker comprising a maleimide moiety (Mai), C2(PEG)m, valine-citrulline (Val-Cit or “VC”), and a pABC provides these functional features. In some embodiments, a linker comprising a maleimide moiety (Mai), C2(PEG)m, valine-alanine (Val-Ala or “VA”), and a pABC provides these functional features. In some embodiments, a linker comprising a maleimide moiety (Mai), C2(PEG)m, and Asn provides these functional features. In some embodiments, m is 0, 1, 2, or 3. In some embodiments, m is 2. In some embodiments, the drug moiety is eribulin.

[0299] In some embodiments, the antibody moiety is conjugated to the drug moiety via a linker comprising a maleimide moiety (Mai), a polyethylene glycol (PEG) moiety, and a cleavable amino acid moiety. In some embodiments, the antibody moiety is conjugated to the drug moiety via a linker comprising a maleimide moiety (Mai), a polyethylene glycol (PEG) moiety, a cleavable amino acid moiety, and a pABC.

[0300] In some embodiments, the antibody moiety is conjugated to the drug moiety via a linkerpayload conjugate of Formula (Ila):, wherein: D is the drug moiety (e.g., a cytotoxic agent, e.g., erihulin); Y is a cleavable moiety; and Z is absent or a spacer unit. In some embodiments, the drug moiety is eribulin. In some embodiments, Y comprises a cleavable amino acid moiety. In some embodiments, Y comprises Val-Cit. In some embodiments, Y comprises Vai-Ala. In some embodiments, Y comprises aspartic acid (Asp). In some embodiments, Y comprises asparagine (Asn). In some embodiments, Y comprises Val-Lys(Me)2. In some embodiments, Y comprises Ala- Lys(Me)2. In some embodiments, Y comprises Asp(OMe). In some embodiments, Z is absent. In some embodiments, Z comprises pAB. In some embodiments, Z comprises pABC.

[0301] In some embodiments, Y comprises Val-Cit and Z comprises pABC. In some embodiments, Y comprises Val-Ala and Z comprises pABC. In some embodiments, Y comprises Val-Lys(Me)2and Z comprises pABC. In some embodiments, Y comprises Ala-Lys(Me)2and Z comprises pABC. In some embodiments, Y comprises Asp and Z is absent. In some embodiments, Y comprises Asn and Z is absent. In some embodiments, Y comprises Asp(OMe) and Z is absent. In some embodiments, D comprises eribulin.

[0302] In some embodiments of linker-payload conjugates disclosed herein, the drug moiety is eribulin. The structures of exemplary linkers attached to eribulin that may be joined to TROP2 antibodies (e.g. , antibodies as disclosed herein) are provided in Table 11.

[0303] In some embodiments, the ADC comprises a cleavable linker and an internalizing anti- TROP2 antibody or internalizing antigen-binding fragment thereof as disclosed herein. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises three heavy chain complementarity determining regions (HCDRs) comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 5 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises three heavy chain complementarity determining regions (HCDRs) comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 14 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system. In some embodiments, the anti-TROP2antibody or antigen-binding fragment thereof comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system.

[0304] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 56, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 58. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 63. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0305] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 104 and a light chain comprising an amino acid sequence of SEQ ID NO: 107. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 104 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 105 and a light chain comprising an amino acid sequence of SEQ ID NO: 107. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 105 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 183 and a light chain comprising an amino acid sequence of SEQ ID NO: 107. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 183 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 107. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 110. In some embodiments, the anti- TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 112. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 101 and a light chain comprising an amino acid sequence of SEQ ID NO: 112. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 101 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 112. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 115. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 112. In some embodiments, theanti-TR0P2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

[0306] In some embodiments, the internalizing antibody is 16K21. In some embodiments, the 16K21 antibody comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 1, HCDR2 comprising SEQ ID NO: 3, HCDR3 comprising SEQ ID NO: 4; LCDR1 comprising SEQ ID NO: 8, LCDR2 comprising SEQ ID NO: 9, and LCDR3 comprising SEQ ID NO: 10, as defined by the Kabat numbering system; or three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 11, HCDR2 comprising SEQ ID NO: 12, HCDR3 comprising SEQ ID NO: 13; LCDR1 comprising SEQ ID NO: 15, LCDR2 comprising SEQ ID NO: 16, and LCDR3 comprising SEQ ID NO: 17, as defined by the IMGT numbering system. In some embodiments, the 16K21 antibody comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61 ; or a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66. In some embodiments, the 16K21 antibody comprises a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115. In some embodiments, p is from 1 to 8, or 2 to 8. In some embodiments, p is from 2 to 4. In some embodiments, p is 2.

[0307] In some embodiments, the internalizing antibody or internalizing antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 76. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 72. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 77. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 69, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 73. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 76. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 72. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence ofSEQ ID NO: 77. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 70, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 73.

[0308] In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 126 and a light chain comprising an amino acid sequence of SEQ ID NO: 129. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 122 and a light chain comprising an amino acid sequence of SEQ ID NO: 133. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 126 and a light chain comprising an amino acid sequence of SEQ ID NO: 130. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 122 and a light chain comprising an amino acid sequence of SEQ ID NO: 134. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 127 and a light chain comprising an amino acid sequence of SEQ ID NO: 129. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 123 and a light chain comprising an amino acid sequence of SEQ ID NO: 133. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 127 and a light chain comprising an amino acid sequence of SEQ ID NO: 130. In some embodiments, the anti-TROP2 antibody or antigen-binding fragment thereof comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 123 and a light chain comprising an amino acid sequence of SEQ ID NO: 134.

[0309] In some embodiments, the internalizing antibody is 16K21. In some embodiments, p is from 1 to 8, or 2 to 8. In some embodiments, p is from 2 to 4. In some embodiments, p is 2.Antibody-Drug Conjugates

[0310] In various embodiments, an anti-TROP2 antibody moiety (including an antigen-binding fragment thereof) disclosed herein may be conjugated (i.e., covalently attached, e.g., by a linker) to a drug moiety, wherein the drug moiety when not conjugated to an antibody moiety has a cytotoxic or cytostatic effect. In some embodiments, the drug moiety exhibits reduced or no cytotoxicity when bound in an antibody-drug conjugate but resumes cytotoxicity after cleavage from the linker and antibody moiety. In various embodiments, the drug moiety exhibits reduced or no bystander killing when bound in an antibody-drug conjugate (e.g., using a non-cleavable linker) but exhibits increased bystander killing after cleavage from an antibody-drug conjugate (e.g., an antibody-drug conjugate having a cleavable Val-Cit, Val-Ala, Asp, or Asn cleavable moiety).

[0311] 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 and unpredictable 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 moiety; (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 moiety; (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 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. Screening 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.

[0312] 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 TROP2. In some embodiments, the cytotoxic and / or cytostatic activity of the ADC is dependent on TROP2 expression level on a cell surface. In some embodiments, the disclosed ADCs are particularly effective at killing cancer cells expressing a high level of TROP2, as compared to cancer cells expressing the same antigen at a low level. Exemplary high TROP2-expressing cancers include but are not limited to bladder cancer, breast cancer, cervical carcinoma, cholangiocarcinoma, colorectal cancer, endometrial cancer, esophageal cancer, gastric cancer, glioma, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), ovarian cancer, pancreatic cancer, and skin cancer. In some embodiments, the disclosed ADCs are particularly effective at killing high TROP2-expressing cancers such as cholangiocarcinoma, breast cancer, or NSCLC.

[0313] 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, as compared to comparable treatment with an ADC comprising a non-cleavable linker.

[0314] In some embodiments, the disclosed ADCs also demonstrate an increased safety profile due to substitution of residues in the Fc domain of the anti-TROP2 antibody. In some embodiments, the disclosed ADCs comprise an anti-TROP2 antibody that comprises an IgGl Fc domain that has been mutated to reduce binding to a Fey receptor (FcyR) as compared to an IgGl Fc-containing antibody with a wild-type IgGl Fc domain. These substitutions reduce the ability of the ADC to bind to various cell receptors, such as a Fey receptor (FcyR), and other immune molecules, as compared to an ADC comprising an anti-TROP2 antibody without these substitutions. Without being bound by theory, the reduced binding of an ADC to a FcyR may reduce non-antigen mediated uptake by neutrophils, thereby reducing neutropenia in a treated subject.

[0315] In some embodiments, the disclosed ADCs demonstrate superior properties (e.g., antigenbinding specificity (e.g., epitope and / or affinity), site-specific linker-payload conjugation, tolerability, in vitro cytotoxicity, safety profile) compared to other TROP2 ADCs (e.g., DS- 1062a or IMMU-132). In some embodiments, the disclosed ADCs have superior antigen-binding specificity compared to other TROP2 ADCs (e.g., DS-1062a or IMMU-132). In some embodiments, the disclosed ADCs have superior site-specific linker-payload conjugation compared to other TROP2 ADCs (e.g., DS- 1062a or IMMU-132). In some embodiments, the disclosed ADCs have superior tolerability compared to other TROP2 ADCs (e.g., DS-1062a or IMMU-132). In some embodiments, the disclosed ADCs have superior in vitro cytotoxicity compared to other TROP2 ADCs (e.g., DS- 1062a or IMMU-132). In some embodiments, the disclosed ADCs have a superior safety profile (e.g., reduced Fey receptor interactions) compared to other TROP2 ADCs (e.g., DS-1062a or IMMU-132). In some embodiments, the disclosed ADCs have a superior property in more than one of the listed categories (e.g., all of them).

[0316] Provided herein are ADC compounds comprising an antibody or antigen-binding fragment thereof (Ab) which targets a tumor cell, a 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., TROP2) 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. Preferred ADCs are thus those that internalize upon binding to a target cell, undergo degradation, and release the drug moiety to kill cancer cells. The 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.

[0317] In various embodiments, an anti-TROP2 ADC disclosed herein is conjugated to eribulin via a linker comprising C2. In some embodiments, using a linker comprising a spacer unit comprising C2may provide benefits over other linkers when conjugated to an anti-TROP2 ADC disclosed herein. In some embodiments, the spacer unit comprising C2is or comprises C2(PEG)m, wherein m is 1-3 (e.g., C2(PEG)1, C2(PEG)2, or C2(PEG)3). In some embodiments, using a linker comprising a spacer unit comprising C2(PEG)m, wherein m is 1-3, may provide benefits, as compared to alternate linkers notcomprising a unit of C2(PEG)m, wherein m is 1-3, when conjugated to an anti-TROP2 ADC disclosed herein. These benefits may include, e.g., improved conjugation stability, improved plasma stability, and / or in vivo anti-tumor activity compared to other linkers comprising alternative spacer units. In some embodiments, without being bound by theory, benefits of using an anti-TROP2 ADC conjugated to eribulin via a linker comprising C2(PEG)m, wherein m is 1-3, may include improved conjugation stability, improved plasma stability, and / or in vivo anti-tumor activity. In some embodiments, an anti-TROP2 ADC conjugated to eribulin via a linker comprising C2(PEG)m, wherein m is 1-3, and VCP demonstrates superior properties compared to other anti-TROP2-eribulin ADCs. In some embodiments, an anti-TROP2 ADC conjugated to eribulin via a linker comprising C2(PEG)m, wherein m is 1-3, and N demonstrates superior properties compared to other anti-TROP2-eribulin ADCs. In some embodiments, m is 2. Exemplary evidence of the superior benefits of such antibodydrug conjugates is shown in Example 7.

[0318] An exemplary ADC has Formula (I):Ab-(L-D)p(I) wherein Ab is an antibody moiety (i.e., an antibody or antigen-binding fragment), L is a linker moiety, D is a drug moiety, and p is the number of drug moieties per antibody moiety.

[0319] In some embodiments, the antibody-drug conjugate comprises a conjugate of Formula (II):wherein: Ab is an antibody or antigen-binding fragment thereof; D is a drug moiety (e.g., a cytotoxic agent); Y is a cleavable moiety; Z is absent or a spacer unit; and p is an integer from 1 to 8.

[0320] In some embodiments, the drug moiety is eribulin. In some embodiments, Y comprises a cleavable amino acid moiety. In some embodiments, Y comprises Val-Cit. In some embodiments, Y comprises Vai-Ala. In some embodiments, Y comprises aspartic acid (Asp). In some embodiments, Y comprises asparagine (Asn). In some embodiments, Y comprises Val-Lys(Me)2. In some embodiments, Y comprises Ala-Lys(Me)2. In some embodiments, Y comprises Asp(OMe). In some embodiments, Z is absent. In some embodiments, Z comprises pAB. In some embodiments, Z comprises pABC.

[0321] In some embodiments, Y comprises Val-Cit and Z comprises pABC. In some embodiments, Y comprises Val-Ala and Z comprises pABC. In some embodiments, Y comprises Asp and Z is absent. In some embodiments, Y comprises Val-Lys(Me)2and Z comprises pABC. In some embodiments, Y comprises Ala-Lys(Me)2and Z comprises pABC. In some embodiments, Y comprises Asn and Z is absent. In some embodiments, Y comprises Asp(OMe) and Z is absent. In some embodiments, D comprises eribulin.

[0322] In some embodiments, the antibody-drug conjugate comprises a conjugate of Formula (III):, wherein: Ab is an antibody or antigen-binding fragment thereof; D is a drug moiety (e.g., a cytotoxic agent); Y is a cleavable moiety; Z is absent or a spacer unit; and p is an integer from 1 to 8.

[0323] In some embodiments, the drug moiety is eribulin. In some embodiments, Y comprises a cleavable amino acid moiety. In some embodiments, Y comprises Val-Cit. In some embodiments, Y comprises Val-Ala. In some embodiments, Y comprises aspartic acid (Asp). In some embodiments, Y comprises asparagine (Asn). In some embodiments, Y comprises valine-dimethylated lysine (Val- Lys(Me)2). In some embodiments, Y comprises alanine-dimethylated lysine (Ala-Lys(Me)2). In some embodiments, Y comprises methylated aspartic acid (Asp(OMe)). In some embodiments, Z is absent. In some embodiments, Z comprises pAB. In some embodiments, Z comprises pABC.

[0324] In some embodiments, Y comprises Val-Cit and Z comprises pABC. In some embodiments, Y comprises Val-Ala and Z comprises pABC. In some embodiments, Y comprises Val-Lys(Me)2and Z comprises pABC. In some embodiments, Y comprises Ala-Lys(Me)2and Z comprises pABC. In some embodiments, Y comprises Asp and Z is absent. In some embodiments, Y comprises Asn and Z is absent. In some embodiments, Y comprises Asp(OMe) and Z is absent. In some embodiments, D comprises eribulin.

[0325] In some embodiments, the present disclosure describes methods of preparing an antibodydrug conjugate of Formula (II). In some embodiments, the method comprises:- providing one or more compounds of Formula (Ila)wherein: D is a cytotoxic agent; Y is a cleavable moiety; and Z is absent or a spacer unit; and- conjugating the one or more compounds of Formula (Ila) to an antibody or antigen-binding fragment, to provide an antibody-drug conjugate of Formula (II):wherein Ab is the antibody or antigen-binding fragment.

[0326] In some embodiments, the present disclosure describes methods of preparing an antibodydrug conjugate of Formula (III). In some embodiments, the method comprises:- providing one or more compounds of Formula (Ila), wherein: D is a cytotoxic agent; Y is a cleavable moiety; and Z is absent or a spacer unit;- conjugating the one or more compounds of Formula (Ila) to an antibody or antigen-binding fragment, to provide an antibody-drug conjugate of Formula (II):wherein Ab is the antibody or antigen-binding fragment; and- hydrolyzing the succinimide ring in the compound of Formula (II), to provide the compound of Formula (III)

[0327] In some embodiments, the step of hydrolyzing the succinimide ring in the compound of Formula (II) comprises a pH from about 7.4 to about 9.2. In some embodiments, the pH is about 7.4 to about 8.5. In some embodiments, the pH is about 7.4. In some embodiments, the step of hydrolyzing the succinimide ring in the compound of Formula (II) comprises a temperature of about 37 °C. In some embodiments, the step of hydrolyzing the succinimide ring in the compound of Formula (II) is completed in about 24 hours or less.Drug Moieties

[0328] The drug moiety (D) of the ADCs described herein can be any chemotherapeutic agent.Useful classes of chemotherapeutic agents include, for example, anti-tubulin agents, topoisomerase I inhibitor agents, or immunostimulatory agents. In certain embodiments, the drug moiety is an anti- tubulin agent. In some embodiments, the drug moiety for use in the ADCs disclosed herein is eribulin. In some embodiments, the drug moiety is a topoisomerase inhibitor agent.

[0329] In various embodiments, the drug moiety is eribulin. In these embodiments, the linker of the ADC is attached via the C-35 amine on eribulin.

[0330] In certain embodiments, an intermediate, such as a precursor of a linker disclosed above, is reacted with the drug moiety under appropriate conditions. In certain embodiments, reactive groups are used on the drug and / or the intermediate or linker. The product of the reaction between the drug and the intermediate, or the derivatized drug, is subsequently reacted with the antibody or antigenbinding fragment under appropriate conditions, e.g., according to the methods discussed below. Alternatively, the linker or intermediate may first be reacted with the antibody or a derivatized antibody, and then reacted with the drug or derivatized drug.

[0331] A number of different reactions are available for covalent attachment of drugs and / or linkers to the antibody moiety. This is often accomplished by reaction of one or more amino acid residues of the antibody molecule, including the amine groups of lysine, the free carboxylic acid groups of glutamic acid and aspartic acid, the sulfhydryl groups of cysteine, and the various moieties of the aromatic amino acids. For instance, non-specific covalent attachment may be undertaken using a carbodiimide reaction to link a carboxy (or amino) group on a compound to an amino (or carboxy) group on an antibody moiety. Additionally, bifunctional agents such as dialdehydes or imidoesters may also be used to link the amino group on a compound to an amino group on an antibody moiety. Also available for attachment of drugs to binding agents is the Schiff base reaction. This method involves the periodate oxidation of a drug that contains glycol or hydroxy groups, thus forming an aldehyde which is then reacted with the binding agent. Attachment occurs via formation of a Schiff base with amino groups of the binding agent. Isothiocyanates may also be used as coupling agents for covalently attaching drugs to binding agents. Other techniques are known to the skilled artisan and within the scope of the present disclosure.

[0332] To accomplish site-specific conjugation of linkers and / or drug moieties to an antibody or antigen-binding fragment thereof, in some embodiments, a microbial transglutaminase is used to conjugate the linker or an intermediate comprising an acyl donor substrate with the antibody or a derivatized antibody, e.g., at an engineered lysine residue as an acyl acceptor. In some embodiments, a linker comprising a thiol-reactive group is used to generate a conjugated antibody or antigenbinding fragment, e.g., by reacting with the antibody or antigen-binding fragment at a cysteine at amino acid position 80, 118, 140, 149, or 239.

[0333] Methods to accomplish site-specific conjugation of linkers and / or drug moieties to an antibody or antigen-binding fragment for the production of ADCs are known in the art and disclosed in PCT applications WO 2017 / 213267, WO 2017 / 106643, and WO 2016 / 205618, all herein incorporated by reference in their entirety.Drug Loading

[0334] Drug loading is represented by p, and is also referred to herein as the drug-to-antibody ratio (DAR). In some embodiments, drug loading may range from 1-20 (i.e., 1-20 copies of the linkerpayload conjugate attached to each antibody moiety), e.g., 1 to 8 drug moieties per antibody moiety.In some embodiments, p is an integer from 1 to 8. In some embodiments, p is an integer from 1 to 8, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2. In some embodiments, p is an integer from 2 to 8, 2 to 7, 2 to 6, 2 to 5, 2 to 4, or 2 to 3. In some embodiments, p is an integer from 1 to 2. In some embodiments, p is an integer from 2 to 3. In some embodiments, p is 1 , 2, 3, 4, 5, 6, 7, or 8. In some embodiments, p is 2. In some embodiments, drug loading may be expressed as an average loading in a population of antibodies, e.g., an average loading of about 1-8, e.g., about 2-4.

[0335] Drug loading may be limited by the number of attachment sites on the antibody moiety. In some embodiments, the linker moiety (L) of the ADC attaches to the antibody moiety through a chemically active group on one or more amino acid residues on the antibody moiety. For example, the linker may be attached to the antibody moiety via a free amino, imino, hydroxyl, thiol, or carboxyl group (e.g., to the N or C terminus, to the epsilon amino group of one or more lysine residues, to the free carboxylic acid group of one or more glutamic acid or aspartic acid residues, or to the sulfhydryl group of one or more cysteine residues). The site to which the linker is attached can be a natural residue in the amino acid sequence of the antibody moiety, or it can be introduced into the antibody moiety, e.g., by DNA recombinant technology (e.g., by introducing a cysteine or lysine residue into the amino acid sequence) or by protein biochemistry (e.g. , by reduction, pH adjustment, or hydrolysis). In some embodiments, the linker is attached to the antibody moiety via a cysteine residue. In some embodiments, the linker is attached to the antibody moiety via a lysine residue.

[0336] In some embodiments, the number of drug moieties that can be conjugated to an antibody moiety is limited by the number of free cysteine residues. For example, where the attachment is a cysteine thiol group, an antibody may have only one or a few cysteine thiol groups, or may have only one or a few sufficiently reactive thiol groups through which a linker may be attached. Generally, antibodies do not contain many free and reactive cysteine thiol groups that may be linked to a drug moiety. Indeed, most cysteine thiol residues in antibodies exist as disulfide bridges. Over-attachment of linker-toxin to an antibody may destabilize the antibody by reducing the cysteine residues available to form disulfide bridges. Therefore, an optimal drug:antibody ratio should increase potency of the ADC (by increasing the number of attached drug moieties per antibody) without destabilizing the antibody moiety. In some embodiments, an optimal ratio may be about 2.

[0337] In some embodiments, a linker attached to an antibody moiety through a Mai moiety may provide a ratio of about 2. In some embodiments, an ADC comprising Mal-(PEG)2-Val-Cit-pABC- eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has aratio of about 2. . In some embodiments, an ADC comprising Mal-C2-Val-Cit-pABC-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)1-Val-Cit-pABC-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)2- Val-Cit-pABC-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)3-Val-Cit-pABC-eribulin joinedto an anti-TR0P2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-(PEG)2- Vai- Ala-pABC-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)1-Val- Ala-pABC-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)2- Val-Ala-pABC-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)3-Val-Ala-pABC-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has aratio of about 2. In some embodiments, an ADC comprising Mal-(PEG)2-N-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal- C2-N-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)1-N-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)2-N-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has a ratio of about 2. In some embodiments, an ADC comprising Mal-C2(PEG)3-N-eribulin joined to an anti-TROP2 antibody as disclosed herein (e.g., 16K21) has aratio of about 2. In some embodiments, the anti-TROP2 antibody comprises three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 1, HCDR2 comprising SEQ ID NO: 3, HCDR3 comprising SEQ ID NO: 4; LCDR1 comprising SEQ ID NO: 8, LCDR2 comprising SEQ ID NO: 9, and LCDR3 comprising SEQ ID NO: 10, as defined by the Kabat numbering system; or three heavy chain CDRs and three light chain CDRs as follows: HCDR1 comprising SEQ ID NO: 11, HCDR2 comprising SEQ ID NO: 12, HCDR3 comprising SEQ ID NO: 13; LCDR1 comprising SEQ ID NO: 15, LCDR2 comprising SEQ ID NO: 16, and LCDR3 comprising SEQ ID NO: 17, as defined by the IMGT numbering system. In some embodiments, the anti-TROP2 antibody comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

[0338] In some embodiments, an antibody moiety is exposed to reducing conditions prior to conjugation in order to generate one or more free cysteine residues. An antibody may be reduced with a reducing agent such as dithiothreitol (DTT) or tris(2-carboxyethyl)phosphine (TCEP), under partial or total reducing conditions, to generate reactive cysteine thiol groups. Unpaired cysteines may be generated through partial reduction with limited molar equivalents of TCEP, which preferentially reduces the interchain disulfide bonds which link the light chain and heavy chain (one pair per H-L pairing) and the two heavy chains in the hinge region (two pairs per H-H pairing in the case of human IgGl) while leaving the intrachain disulfide bonds intact. Stefano et al. (2013) Methods Mol. Biol. 1045:145-71. In some embodiments, disulfide bonds within the antibodies are reduced electrochemically, e.g., by employing a working electrode that applies an alternating reducing and oxidizing voltage. This approach can allow for on-line coupling of disulfide bond reduction to ananalytical device (e.g. , an electrochemical detection device, an NMR spectrometer, or a mass spectrometer) or a chemical separation device (e.g., a liquid chromatograph (e.g., an HPLC) or an electrophoresis device (see, e.g., U.S. Publ. No. 20140069822)). In certain embodiments, an antibody is subjected to denaturing conditions to reveal reactive nucleophilic groups on amino acid residues, such as lysine or cysteine.

[0339] The drug loading of an ADC may be controlled in different ways, e.g., by: (i) limiting the molar excess of drug-linker intermediate or linker reagent relative to antibody; (ii) limiting the conjugation reaction time or temperature; (iii) partial or limiting reductive conditions for cysteine thiol modification; and / or (iv) engineering by recombinant techniques the amino acid sequence of the antibody such that the number and position of cysteine or lysine residues is modified for control of the number and / or position of linker-payload conjugate attachments.

[0340] In some embodiments, free cysteine residues are introduced into the amino acid sequence of the antibody moiety. For example, cysteine engineered antibodies can be prepared wherein one or more amino acids of a parent antibody are replaced with a cysteine amino acid. Any form of antibody may be so engineered, i.e., mutated. For example, a parent Fab antibody fragment may be engineered to form a cysteine engineered Fab referred to as a “ThioFab.” Similarly, a parent monoclonal antibody may be engineered to form a “ThioMab.” A single site mutation yields a single engineered cysteine residue in a ThioFab, whereas a single site mutation yields two engineered cysteine residues in a ThioMab, due to the dimeric nature of the IgG antibody. DNA encoding an amino acid sequence variant of the parent polypeptide can be prepared by a variety of methods known in the art (see, e.g. , the methods described in W02006 / 034488). These methods include, but are not limited to, preparation by site-directed (or oligonucleotide-mediated) mutagenesis, PCR mutagenesis, and cassette mutagenesis of an earlier prepared DNA encoding the polypeptide. Variants of recombinant antibodies may also be constructed by restriction fragment manipulation or by overlap extension PCR with synthetic oligonucleotides. ADCs of Formula (I) include, but are not limited to, antibodies that have 1, 2, 3, or 4 engineered cysteine amino acids. See, e.g., Lyon et al. (2012) Methods Enzymol. 502: 123-38. In some embodiments, one or more free cysteine residues are already present in an antibody moiety, without the use of engineering, in which case the existing free cysteine residues may be used to conjugate the antibody moiety to a drug moiety.

[0341] Where more than one nucleophilic group reacts with a drug-linker intermediate or a linker moiety reagent followed by drug moiety reagent, in a reaction mixture comprising multiple copies of the antibody moiety and linker moiety, then the resulting product can be a mixture of ADC compounds with a distribution of one or more drug moieties attached to each copy of the antibody moiety in the mixture. In some embodiments, the drug loading in a mixture of ADCs resulting from a conjugation reaction ranges from 1 to 8 drug moieties attached per antibody moiety. The average number of drug moieties per antibody moiety (i.e., the average drug loading, or average p) may be calculated by any conventional method known in the art, e.g., by mass spectrometry (e.g., reverse-phase LC-MS), and / or high-performance liquid chromatography (e.g., HIC-HPLC). In some embodiments, the average number of drug moieties per antibody moiety is determined by hydrophobic interaction chromatography-high performance liquid chromatography (HIC-HPLC). In some embodiments, the average number of drug moieties per antibody moiety is determined by reverse-phase liquid chromatography-mass spectrometry (LC-MS). In some embodiments, the average number of drug moieties per antibody moiety is from about 1 to about 8; from about 1 to about 6; from about 1 to about 3; or from about 1 to about 2. In some embodiments, the average number of drug moieties per antibody moiety is about 2.

[0342] Individual ADC compounds having particular DAR ratios, or “species,” may be identified in the mixture, e.g., by mass spectroscopy and separated, e.g., by ultra-performance liquid chromatography (UPLC) or HPLC, e.g., hydrophobic interaction chromatography (HIC-HPLC). In certain embodiments, a homogeneous or nearly homogenous ADC with a single loading value may be isolated from the conjugation mixture, e.g., by electrophoresis or chromatography.

[0343] The present disclosure includes methods of producing the described ADCs. Briefly, the ADCs comprise an antibody or antigen-binding fragment as the antibody moiety, a drug moiety, and a linker that joins the drug moiety and the antibody moiety. In some embodiments, the ADCs are prepared using a linker having reactive functionalities for covalently attaching to the drug moiety and to the antibody moiety. For example, in some embodiments, a cysteine thiol of an antibody moiety forms a bond with a reactive functional group of a linker or a drug-linker intermediate (e.g., a maleimide moiety) to make an ADC. In some embodiments, an engineered lysine residue of an antibody moiety forms a bond with an acyl donor substrate of a linker or a linker intermediate (e.g., a carbobenzoxy-L-glutaminyl-glycine moiety), the linker or linker intermediate comprising a reactive group that can be conjugated to a functional agent (e.g., a cleavable peptide comprising eribulin).

[0344] In some embodiments, an ADC is produced by contacting an antibody moiety with a linker and a drug moiety in a sequential manner, such that the antibody moiety is covalently linked to the linker first, and then the pre-formed antibody-linker intermediate reacts with the drug moiety. The antibody-linker intermediate may or may not be subjected to a purification step prior to contacting the drug moiety. In other embodiments, an ADC is produced by contacting an antibody moiety with a linker-payload conjugate pre-formed by reacting a linker with a drug moiety. The pre-formed linkerpayload conjugate may or may not be subjected to a purification step prior to contacting the antibody moiety. In other embodiments, the antibody moiety contacts the linker and the drug moiety in one reaction mixture, allowing simultaneous formation of the covalent bonds between the antibody moiety and the linker, and between the linker and the drug moiety. In some embodiments, an ADC is produced by reacting an antibody moiety with a linker-payload conjugate, e.g., Mal-(PEG)2-Val-Cit- pABC-eribulin, under conditions that allow conjugation. The conditions that allow conjugation may involve any biochemical methods known in the art for conjugating an ADC. These conditions include, but are not limited to, incubation at room temperature in a suitable buffer (e.g., 1 x DBPS, 0.1 M Tris-Glycine at pH 7.4, or 10% propylene glycol:90% 1 x DPBS). The conjugation conditions may or may not include the presence of an enzyme (e.g., transglutaminase).

[0345] The ADCs prepared according to the methods described above may be subjected to one or more purification steps. The purification step may involve any biochemical methods known in the art for purifying proteins, or any combination of methods thereof. These include, but are not limited to, tangential flow filtration (TFF), affinity chromatography, ion exchange chromatography, any charge or isoelectric point-based chromatography, mixed mode chromatography, e.g., CHT (ceramic hydroxyapatite), hydrophobic interaction chromatography, size exclusion chromatography, dialysis, filtration, selective precipitation, desalting chromatography, or any combination thereof.Therapeutic Uses

[0346] Disclosed herein are methods of using the disclosed antibodies and ADCs in treating a subject for a disorder, e.g., an oncologic disorder. Antibodies and / or ADCs may be administered alone or in combination with a second therapeutic agent, and may be administered in any pharmaceutically acceptable formulation, dosage, and dosing regimen. Treatment efficacy may be evaluated for toxicity as well as indicators of efficacy and adjusted accordingly. Efficacy measures include, but are not limited to, a cytostatic and / or cytotoxic effect observed in vitro or in vivo, reduced tumor volume, tumor growth inhibition, and / or prolonged survival.

[0347] Methods of determining whether an antibody or ADC exerts a cytostatic and / or cytotoxic effect on a cell are known. For example, the cytotoxic activity of an antibody or ADC can be measured by: exposing mammalian cells expressing a target protein of the antibody or ADC (e.g., TROP2) in a cell culture medium; culturing the cells for a period of time, e.g., from about 6 hours to about 5 days; and measuring cell viability. Cell-based in vitro assays may also be used to measure viability (proliferation), cytotoxicity, growth inhibition, and induction of apoptosis (caspase activation) of the antibody or ADC.

[0348] In some embodiments, to determine cytotoxicity, necrosis or apoptosis (programmed cell death) may be measured. Necrosis is typically accompanied by increased permeability of the plasma membrane, swelling of the cell, and rupture of the plasma membrane. Apoptosis is typically characterized by membrane blebbing, condensation of cytoplasm, and the activation of endogenous endonucleases. Determination of any of these effects on cancer cells indicates that an antibody or ADC is useful in the treatment of cancers.

[0349] Cell viability may be measured, e.g., by determining in a cell the uptake of a dye such as neutral red, trypan blue, Crystal Violet, or ALAMAR™ blue. See, e.g., Page et al. (1993) Inti. J. Oncology 3:473-6. In such an assay, the cells are incubated in media containing the dye, the cells are washed, and the remaining dye, reflecting cellular uptake of the dye, is measured spectrophotometrically. In certain embodiments, in vitro potency of prepared antibodies or ADCs is assessed using a Crystal Violet assay. Crystal Violet is a triaryhnethane dye that accumulates in thenucleus of viable cells. In this assay, cells are exposed to the antibodies or ADCs or control agents for a defined period of time, after which, cells are stained with crystal violet, washed copiously with water, then solubilized with 1% SDS and read spectrophotometrically. The protein-binding dye sulforhodamine B (SRB) can also be used to measure cytoxicity. Skehan et al. (1990) J. Natl. Cancer Inst. 82:1107-12.

[0350] Apoptosis can be quantitated, for example, by measuring DNA fragmentation. Commercial photometric methods for the quantitative in vitro determination of DNA fragmentation are available. Examples of such assays, including TUNEL (which detects incorporation of labeled nucleotides in fragmented DNA) and ELISA-based assays, are described in Biochemica (1999) No. 2, pp. 34-37 (Roche Molecular Biochemicals).

[0351] Apoptosis may also be determined by measuring morphological changes in a cell. For example, as with necrosis, loss of plasma membrane integrity can be determined by measuring uptake of certain dyes (e.g., a fluorescent dye such as acridine orange or ethidium bromide). A method for measuring apoptotic cell number has been described by Duke and Cohen, Current Protocols in Immunology (Coligan et al., eds. (1992) pp. 3.17.1-3.17.16). Cells also can be labeled with a DNA dye (e.g., acridine orange, ethidium bromide, or propidium iodide) and the cells observed for chromatin condensation and margination along the inner nuclear membrane. Other morphological changes that can be measured to determine apoptosis include, e.g., cytoplasmic condensation, increased membrane blebbing, and cellular shrinkage.

[0352] In some embodiments, the present disclosure provides a method of killing, inhibiting or modulating the growth of, or interfering with the metabolism of, a cancer cell or tissue by disrupting tubulin. The method may be used with any subject where disruption of tubulin provides a therapeutic benefit.

[0353] In various embodiments, the disclosed antibodies and / or ADCs may be administered to affect any cell or tissue that expresses TROP2, such as a TROP2-expressing cancer cell or tissue. An exemplary embodiment comprises a method of inhibiting TROP2 -mediated cell signaling or a method of killing a cell. The method may be used with any cell or tissue that expresses TROP2, such as a cancerous cell or a metastatic lesion. Non-limiting examples of TROP2-expressing cancers include cholangiocarcinoma (bile duct cancer), bladder cancer, breast cancer, esophageal cancer, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, and skin cancer. Non-limiting examples of TROP2- expressing cells include HuCCTl and SNU-308 human biliary tract cancer cells, BxPC3 human pancreatic adenocarcinoma cells, and cells comprising a recombinant nucleic acid encoding TROP2 or a portion thereof. Without being bound by theory, the anti-TROP2 antibodies and ADCs disclosed herein may be particularly effective at treating TROP2-expressing cancers by targeting TROP2 expressing cells for degradation or immune clearance, and / or by delivering a drug payload (e.g., eribulin) to cells. In some embodiments, an ADC may be used to deliver a drug payload (e.g.,eribulin) to cells at the initial stages of the epithelial-to-mesenchymal transition (EMT). Without being bound by theory, cancer cells in an epithelial state may express high levels of TROP2. High TROP2 expression in cells may promote proliferation, migration, and metastasis by modulating various cellular signaling pathways, e.g., the PI3K / Akt and / or Wnt / p-catenin pathways. Due to changes in these cellular signaling pathways, cells may progress from an epithelial to mesenchymal state with a concurrent loss of TROP2 expression. These cells may then become immune to treatment with anti-TROP2 antibodies and / or ADCs. In some embodiments, the anti-TROP2 antibodies and ADCs disclosed herein provide for therapeutic effects of binding to TROP2, as well as the cytotoxic effects of delivering payloads such as eribulin, to cells that have not yet begun to metastasize, thus inhibiting cancer cells at the early stage of their growth and development.

[0354] Exemplary methods disclosed herein include the steps of contacting a cell with an antibody and / or ADC as described herein (eg., by administering the antibody and / or ADC to a subject by a suitable route of administration), in an effective amount, e.g., an amount sufficient to kill the cell. The method can be used on cells in culture, e.g., in vitro, ex vivo, or in situ. For example, cells that express TROP2 (e.g., cells collected by biopsy of a tumor or metastatic lesion; cells from an established cancer cell line; or recombinant cells), can be cultured in vitro in culture medium and the contacting step can be affected by adding the antibody or ADC to the culture medium. The method will result in killing of cells expressing TROP2, including in particular tumor cells expressing TROP2.Alternatively, the antibody or ADC can be administered to a subject by any suitable administration route (e.g., intravenous, subcutaneous, or direct contact with a tumor tissue) to have an effect in vivo.

[0355] The in vivo effect of a disclosed antibody and / or ADC can be evaluated in a suitable animal model. For example, xenogenic cancer models can be used, wherein cancer explants or passaged xenograft tissues are introduced into immune compromised animals, such as nude or SCID mice. Klein et al. (1997) Nature Med. 3:402-8. Efficacy may be predicted using assays that measure inhibition of tumor formation, tumor regression or metastasis, and the like. In some embodiments, the anti-TROP2 antibodies and ADCs disclosed herein are more efficacious at inhibiting tumor growth compared to xenograft-bearing mice treated with alternate treatments.

[0356] In vivo assays that evaluate the promotion of apoptosis may also be used. In one embodiment, xenografts from tumor-bearing mice treated with an antibody or ADC disclosed herein are examined for the presence of apoptotic foci and compared to untreated control xenograft-bearing mice, or mice treated with alternate therapeutic compositions. The extent to which apoptotic foci are found in the tumors of the treated mice provides an indication of the therapeutic efficacy of a treatment.

[0357] In various embodiments, provided herein are methods of treating TROP2-expressing cancer. The antibodies and ADCs disclosed herein can be administered to a non-human mammal or human subject for therapeutic purposes. The therapeutic methods may entail administering to a mammal having a tumor, e.g., a tumor expressing TROP2, a biologically effective amount of an antibodydisclosed herein or an ADC comprising a selected chemotherapeutic agent (e.g., erihulin) linked to that antibody.

[0358] In some embodiments, a method of treating a patient having or at risk of having a cancer that expresses TROP2 is provided, comprising administering to the patient a therapeutically effective amount of an antibody and / or ADC of the present disclosure. In some embodiments, the patient is non-responsive or poorly responsive to treatment with a drug moiety (e.g., eribulin) when administered alone, and the patient is administered an antibody or ADC disclosed herein. In other embodiments, the patient is intolerant to treatment with a drug moiety (e.g., eribulin) when administered alone. For instance, to treat a cancer, a patient may require doses of eribulin that lead to systemic toxicity, which are overcome by targeted delivery of the antibodies and / or ADCs disclosed herein to a TROP2-expressing cancer, thereby reducing off-target killing.

[0359] Another exemplary embodiment is a method of reducing or inhibiting growth of a TROP2- expressing tumor, comprising administering a therapeutically effective amount of an antibody and / or ADC disclosed herein. In some embodiments, the treatment is sufficient to reduce or inhibit the growth of the patient's tumor, reduce the number or size of metastatic lesions, reduce tumor load, reduce primary tumor load, reduce invasiveness, prolong survival time, and / or maintain or improve the quality of life. In some embodiments, the tumor is resistant or refractory to treatment with a drug moiety (e.g., eribulin) when administered alone.

[0360] In various embodiments, the methods disclosed herein treat a cholangiocarcinoma, bladder cancer, breast cancer, esophageal cancer, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, or skin cancer.

[0361] Moreover, antibodies and / or ADCs of the present disclosure may be administered to a nonhuman mammal expressing TROP2 for veterinary purposes or as an animal model of human disease. Regarding the latter, such animal models may be usefill for evaluating the therapeutic efficacy of the disclosed antibodies and ADCs (e.g., testing of dosages and time courses of administration).

[0362] In some embodiments, the efficacy of an antibody or ADC may be evaluated by contacting a tumor sample from a subject with the antibody or ADC and evaluating tumor growth rate or volume. In some embodiments, when an antibody or ADC has been determined to be effective, it may be administered to the subject. In some embodiments, the efficacy of an antibody or ADC may be evaluated by contacting a subject with the antibody or ADC and monitoring tumor growth rate or volume.

[0363] The antibodies and ADCs disclosed herein may be administered at a suitable dosage to a patient in need thereof. Dosages and administration protocols for the treatment of cancers using the foregoing methods will vary with the method and the target cancer, and will generally depend on a number of other factors appreciated in the art.

[0364] In various embodiments, treatment involves single bolus or repeated administration of the ADC preparation via an acceptable route of administration.

[0365] The above therapeutic approaches can also be combined with any one of a wide variety of additional surgical, chemotherapy, or radiation therapy regimens.

[0366] Further provided herein are therapeutic uses of the disclosed antibodies and / or ADCs. An exemplary embodiment is the use of an antibody and / or ADC in the treatment of a TROP2 -expressing cancer, such as cholangiocarcinoma, bladder cancer, breast cancer, esophageal cancer, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, or skin cancer. Methods for identifying subjects having cancers that express TROP2 are known in the art and may be used to identify suitable patients for treatment with a disclosed ADC.

[0367] Another exemplary embodiment is the use of an ADC or an antibody or antigen-binding fragment as disclosed herein in the manufacture of a medicament for the treatment of a TROP2- expressing cancer, such as cholangiocarcinoma, bladder cancer, breast cancer, esophageal cancer, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, or skin cancer.Pharmaceutical compositions and formulations

[0368] An antibody or ADC used in the practice of the foregoing methods may be formulated into a pharmaceutical composition suitable for administration to a subject, e.g., a human subject. In some embodiments, the pharmaceutical composition comprises the antibody and / or ADC and a pharmaceutically acceptable carrier suitable for the desired delivery method. Suitable carriers include any material that, when combined with an antibody or ADC disclosed herein, allows that antibody or ADC to retain its anti-tumor function and is generally non-reactive with the patient's immune system. Pharmaceutically acceptable carriers may include any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like that are physiologically compatible. Examples of pharmaceutically acceptable carriers include one or more of water, saline, phosphate buffered saline, dextrose, glycerol, ethanol, mesylate salt, and the like, as well as combinations thereof. In many cases, it will be preferable to include isotonic agents, for example, sugars, polyalcohols such as mannitol, sorbitol, or sodium chloride in the pharmaceutical composition. Pharmaceutically acceptable carriers may further comprise minor amounts of auxiliary substances such as wetting or emulsifying agents, preservatives, or buffers, which enhance the shelf life or effectiveness of the ADC.

[0369] The pharmaceutical compositions described herein may be in a variety of forms. These include, for example, liquid, semi-solid, and solid dosage forms, such as liquid solutions (e.g., injectable and infusible solutions), dispersions or suspensions, tablets, pills, powders, liposomes, and suppositories. The preferred form depends on the intended mode of administration and therapeutic application.

[0370] Pharmaceutical compositions may be solubilized and administered via any route capable of delivering the pharmaceutical composition to the tumor site. Potentially effective routes of administration include, but are not limited to, intravenous, parenteral, intraperitoneal, intramuscular, intratumor, intradermal, intraorgan, orthotopic, and the like. In some embodiments, administration of an antibody-drug conjugate disclosed herein is intravenous. Pharmaceutical compositions can be lyophilized and stored as sterile powders, preferably under vacuum, and then reconstituted in bacteriostatic water (containing, for example, benzyl alcohol preservative) or in sterile water prior to injection. Administration can be either systemic or local. Pharmaceutical compositions may comprise an antibody and / or ADC or a pharmaceutically acceptable salt thereof, e.g., a mesylate salt.

[0371] In various embodiments, kits for use in the laboratory and the therapeutic applications described herein are within the scope of the present disclosure. Such kits may comprise an antibody or ADC disclosed herein and a carrier, package, or container. The carrier, package, or container may be compartmentalized to receive one or more containers such as vials, tubes, and the like, each of the containers) comprising one of the separate elements to be used in a method disclosed herein, and / or a label or insert comprising instructions for use, such as a use described herein. Kits may further comprise one or more other containers associated therewith that comprise materials desirable from a commercial and user standpoint, including buffers, diluents, filters, needles, syringes, carrier, package, container, vial and / or tube labels listing contents and / or instructions for use, and package inserts with instructions for use.

[0372] A label may be present on or with the container to indicate that the pharmaceutical composition is used for a specific therapy or non-therapeutic application, such as a prognostic, prophylactic, diagnostic, or laboratory application. A label may also indicate directions for either in vivo or in vitro use, such as those described herein. Directions and / or other information may also be included on an insert(s) or label(s), which is included with or on the kit. The label may be on or associated with the container. A label may be on a container when letters, numbers, or other characters forming the label are molded or etched into the container itself. A label may be associated with a container when it is present within a receptacle or carrier that also holds the container, e.g., as a package insert. The label may indicate that the pharmaceutical composition is used for diagnosing or treating a condition, such as a cancer as described herein.Exemplary Embodiments of the Disclosure

[0373] In various embodiments, the present disclosure provides novel antibody-drug conjugates capable of specifically binding TROP2.

[0374] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0375] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0376] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-(PEG)2-N, and a drug moiety comprising eribulin.

[0377] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0378] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)1-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0379] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)1-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0380] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)1-N, and a drug moiety comprising eribulin.

[0381] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0382] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0383] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2-N, and a drug moiety comprising eribulin.

[0384] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)2-N, and a drug moiety comprising eribulin.

[0385] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)3-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0386] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)3-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0387] In some embodiments, the antibody-drug conjugate comprises any anti-TROP2 antibody or antigen-binding fragment disclosed herein, a linker comprising Mal-C2(PEG)3-N, and a drug moiety comprising eribulin.

[0388] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0389] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0390] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0391] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0392] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0393] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0394] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and alight chain amino acid sequence of SEQ ID NO: 380, a linker comprising Mal-(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0395] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0396] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0397] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0398] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0399] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-(PEG)2-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0400] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-(PEG)2-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0401] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 380 and alight chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-(PEG)2-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0402] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-(PEG)2-N, and a drug moiety comprising eribulin.

[0403] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-(PEG)2-N, and a drug moiety comprising eribulin.

[0404] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-(PEG)2-N, and a drug moiety comprising eribulin.

[0405] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-(PEG)2-N, and a drug moiety comprising eribulin.

[0406] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-(PEG)2-N, and a drug moiety comprising eribulin.

[0407] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-(PEG)2-N, and a drug moiety comprising eribulin.

[0408] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 380, a linker comprising Mal-(PEG)2-N, and a drug moiety comprising eribulin.

[0409] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0410] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0411] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0412] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0413] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0414] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0415] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 380, a linker comprising Mal-C2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0416] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprisingSEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)1-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0417] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)1-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0418] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)1-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0419] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)1-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0420] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)1-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0421] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)1-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0422] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 380, a linker comprising Mal-C2(PEG)1-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0423] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1)comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0424] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0425] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0426] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)2-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0427] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)2-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0428] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)2-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0429] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 380, a linker comprising Mal-C2(PEG)3-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0430] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chainCDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)3-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0431] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)3-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0432] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)3-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0433] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)3-Val-Cit-pABC, and a drug moiety comprising eribulin.

[0434] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)3-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0435] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)3-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0436] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 380, a linker comprising Mal-C2(PEG)3-Val-Cit- pABC, and a drug moiety comprising eribulin.

[0437] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chainCDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)1-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0438] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)1-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0439] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)1-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0440] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)1-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0441] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)1-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0442] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)1-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0443] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)1-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0444] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chainCDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0445] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0446] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0447] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)2-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0448] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)2-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0449] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)2-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0450] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)2-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0451] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chainCDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)3-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0452] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)3-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0453] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)3-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0454] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)3-Val-Ala-pABC, and a drug moiety comprising eribulin.

[0455] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)3-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0456] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)3-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0457] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)3-Val-Ala- pABC, and a drug moiety comprising eribulin.

[0458] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chainCDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2-N, and a drug moiety comprising eribulin.

[0459] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2-N, and a drug moiety comprising eribulin.

[0460] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2-N, and a drug moiety comprising eribulin.

[0461] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2-N, and a drug moiety comprising eribulin.

[0462] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2-N, and a drug moiety comprising eribulin.

[0463] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2-N, and a drug moiety comprising eribulin.

[0464] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2-N, and a drug moiety comprising eribulin.

[0465] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)1-N, and a drug moiety comprising eribulin.

[0466] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)1-N, and a drug moiety comprising eribulin.

[0467] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)1-N, and a drug moiety comprising eribulin.

[0468] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)1-N, and a drug moiety comprising eribulin.

[0469] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)1-N, and a drug moiety comprising eribulin.

[0470] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)1-N, and a drug moiety comprising eribulin.

[0471] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)1-N, and a drug moiety comprising eribulin.

[0472] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)2-N, and a drug moiety comprising eribulin.

[0473] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprisingSEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)2-N, and a drug moiety comprising eribulin.

[0474] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)2-N, and a drug moiety comprising eribulin.

[0475] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)2-N, and a drug moiety comprising eribulin.

[0476] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)2-N, and a drug moiety comprising eribulin.

[0477] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)2-N, and a drug moiety comprising eribulin.

[0478] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)2-N, and a drug moiety comprising eribulin.

[0479] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-C2(PEG)3-N, and a drug moiety comprising eribulin.

[0480] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 11, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 12, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 13; light chain CDR1 (LCDR1) comprising SEQ ID NO: 15, light chain CDR2 (LCDR2) comprising SEQ ID NO: 16, andlight chain CDR3 (LCDR3) comprising SEQ ID NO: 17, as defined by the IMGT numbering system, a linker comprising Mal-C2(PEG)3-N, and a drug moiety comprising eribulin.

[0481] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 61, a linker comprising Mal-C2(PEG)3-N, and a drug moiety comprising eribulin.

[0482] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66, a linker comprising Mal-C2(PEG)3-N, and a drug moiety comprising eribulin.

[0483] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 181 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)3-N, and a drug moiety comprising eribulin.

[0484] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 179 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)3-N, and a drug moiety comprising eribulin.

[0485] In some embodiments, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment comprising a heavy chain amino acid sequence of SEQ ID NO: 380 and a light chain amino acid sequence of SEQ ID NO: 115, a linker comprising Mal-C2(PEG)3-N, and a drug moiety comprising eribulin.

[0486] In some embodiments of antibody-drug conjugates disclosed herein, the antibody-drug conjugate comprises an anti-TROP2 antibody or antigen-binding fragment thereof which comprises three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system, a linker comprising Mal-(PEG)2-Val-Cit- pABC, Mal-(PEG)2-Val-Ala-pABC, Mal-(PEG)2-N, Mal-C2-Val-Cit-pABC, Mal-C2(PEG)1-Val-Cit- pABC, Mal-C2(PEG)1-Val-Ala-pABC, Mal-C2(PEG)1-N, Mal-C2(PEG)2-Val-Cit-pABC, Mal- C2(PEG)2-Val-Ala-pABC, Mal-C2(PEG)2-N, Mal-C2(PEG)3-Val-Cit-pABC, Mal-C2(PEG)3-Val-Ala- pABC, Mal-C2(PEG)3-N, or Mal-C2-N, and a drug moiety comprising eribulin. Without being bound by theory, one or more of these antibody-drug conjugates may demonstrate superior properties over other ADCs, e.g., those using other antibodies and / or linkers, e.g., as compared to other ADCs disclosed herein (e.g., improved antigen-binding specificity (e.g., epitope and / or affinity), site-specific linker-payload conjugation, tolerability, in vitro cytotoxicity, safety profile). In some embodiments,without being bound by theory, benefits of using an antibody-drug conjugate comprising an anti- TR0P2 antibody or antigen-binding fragment thereof comprising three heavy chain CDRs and three light chain CDRs as follows: heavy chain CDR1 (HCDR1) comprising SEQ ID NO: 1, heavy chain CDR2 (HCDR2) comprising SEQ ID NO: 3, heavy chain CDR3 (HCDR3) comprising SEQ ID NO: 4; light chain CDR1 (LCDR1) comprising SEQ ID NO: 8, light chain CDR2 (LCDR2) comprising SEQ ID NO: 9, and light chain CDR3 (LCDR3) comprising SEQ ID NO: 10, as defined by the Kabat numbering system; a linker comprising Mal-(PEG)2-Val-Cit-pABC, Mal-(PEG)2-Val-Ala-pABC, Mal-(PEG)2-N, Mal-C2-Val-Cit-pABC, Mal-C2(PEG)1-Val-Cit-pABC, Mal-C2(PEG)1-Val-Ala- pABC, Mal-C2(PEG)1-N, Mal-C2(PEG)2-Val-Cit-pABC, Mal-C2(PEG)2-Val-Ala-pABC, Mal- C2(PEG)2-N, Mal-C2...

Claims

CLAIMS1. An anti-TR0P2 antibody or antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment binds specifically to human TR0P2, and wherein the antibody or antigenbinding fragment comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3), wherein(i) the HCDR1 comprises an amino acid sequence of SEQ ID NO: 1, the HCDR2 comprises an amino acid sequence selected from SEQ ID NO: 3, the HCDR3 comprises an amino acid sequence of SEQ ID NO: 4, the LCDR1 comprises an amino acid sequence selected from SEQ ID NO: 8, the LCDR2 comprises an amino acid sequence of SEQ ID NO: 9, and the LCDR3 comprises an amino acid sequence of SEQ ID NO: 10, as defined by the Kabat numbering system; or(ii) the HCDR1 comprises an amino acid sequence of SEQ ID NO: 11, the HCDR2 comprises an amino acid sequence of SEQ ID NO: 12, the HCDR3 comprises an amino acid sequence of SEQ ID NO: 13, the LCDR1 comprises an amino acid sequence selected from SEQ ID NO: 15, the LCDR2 comprises an amino acid sequence of SEQ ID NO: 16, and the LCDR3 comprises an amino acid sequence of SEQ ID NO: 17, as defined by the IMGT numbering system.

2. The anti-TROP2 antibody or antigen-binding fragment of claim 1, wherein the antibody or antigen-binding fragment comprises a heavy chain variable region comprising an amino acid sequence selected from SEQ ID NO: 55 or 175, and a light chain variable region comprising an amino acid sequence selected from SEQ ID NO: 61 or 66.

3. The anti-TROP2 antibody or antigen-binding fragment of claim 1 or claim 2, wherein the antibody or antigen-binding fragment comprises(i) a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66; or(ii) a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

4. The anti-TROP2 antibody or antigen-binding fragment of any one of claims 1 to 3, wherein the antibody or antigen-binding fragment comprises a human IgGl heavy chain constant region.

5. The anti-TROP2 antibody or antigen-binding fragment of any one of claims 1 to 4, wherein the antibody or antigen-binding fragment comprises an IgGl Fc domain or an IgGl Fc domain mutated to reduce binding to a Fey receptor (FcyR) as compared to an IgGl Fc-containing antibodywith a wild type IgGl Fc domain, optionally wherein the mutated IgGl Fc domain comprises one or more of the mutations L234A, L235A, P238S, H268Q, and K274Q.

6. The anti-TROP2 antibody or antigen-binding fragment of any one of claims 1 to 5, wherein the antibody or antigen-binding fragment comprises a human Ig kappa light chain constant region.

7. The anti-TROP2 antibody or antigen-binding fragment of any one of claims 1 to 6, wherein the antibody or antigen-binding fragment comprises(i) a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 115;(ii) a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 115; or(iii) a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

8. The anti-TROP2 antibody or antigen-binding fragment of any one of claims 1 to 7, wherein(a) the antibody or antigen-binding fragment comprises part of a bispecific or multi-specific binding construct; and / or(b) the antibody or antigen-binding fragment is linked to a therapeutic agent or detectable agent.

9. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is the anti-TROP2 antibody or antigen-binding fragment thereof of any one of claims 1 to 7;D is a cytotoxic agent;L is a cleavable linker that covalently attaches Ab to D; and p is an integer from 1 to 8.

10. The antibody-drug conjugate of claim 9, wherein the cytotoxic agent comprises an antitubulin agent, preferably wherein the anti-tubulin agent is eribulin or a salt thereof, preferably eribulin mesylate.

11. The antibody-drug conjugate of claim 9 or claim 10, wherein p is from 2 to 8, optionally wherein p is 2.

12. The antibody-drug conjugate of any one of claims 9 to 11 , wherein cleavage of the conjugate releases the cytotoxic agent from the antibody and linker.

13. The antibody-drug conjugate of any one of claims 9 to 12, wherein the cleavable linker comprises a cleavable peptide moiety.

14. The antibody-drug conjugate of claim 13, wherein the cleavable peptide moiety is cleavable by an enzyme; optionally wherein the cleavable peptide moiety is cleavable by cathepsin or legumain; optionally wherein the cleavable peptide moiety is cleavable by cathepsin B.

15. The antibody-drug conjugate of claim 13 or claim 14, wherein the cleavable peptide moiety comprises an amino acid unit.

16. The antibody-drug conjugate of claim 15, wherein the amino acid unit comprises valinecitrulline (Val-Cit), valine-dimethylated lysine (Val-Lys(Me)2), alanine-dimethylated lysine (Ala- Lys(Me)2), valine-alanine (Val-Ala), asparagine (Asn), aspartic acid (Asp), or methylated aspartic acid (Asp(OMe)).

17. The antibody-drug conjugate of claim 16, wherein the amino acid unit comprises valinecitrulline (Val-Cit), valine-alanine (Val-Ala), or asparagine (Asn).

18. The antibody-drug conjugate of any one of claims 9 to 17, wherein the cleavable linker attaches to the antibody or antigen-binding fragment via a maleimide (Mai) moiety, optionally wherein the Mai moiety comprises a maleimidocaproyl (MC) moiety or a dithiomaleimide (DTM) moiety.

19. The antibody-drug conjugate of claim 18, wherein the Mai moiety is reactive with a cysteine residue on the antibody or antigen-binding fragment.

20. The antibody-drug conjugate of claim 18 or claim 19, wherein the Mai moiety is joined to the antibody or antigen-binding fragment via a cysteine residue on the antibody or antigen-binding fragment.

21. The antibody-drug conjugate of any one of claims 18 to 20, wherein the cleavable linker comprises the Mai moiety and a cleavable peptide moiety.

22. The antibody-drug conjugate of claim 21, wherein the Mai moiety attaches the antibody or antigen-binding fragment to the cleavable peptide moiety in the linker.

23. The antibody-drug conjugate of any one of claims 18 to 22, wherein the cleavable linker comprises Mal-Val-Cit, Mal-Val-Lys(Me)2, Mal-Ala-Lys(Me)2, Mal-Val-Ala, Mal-Asn, Mal-Asp, or Mal-Asp(OMe).

24. The antibody-drug conjugate of any one of claims 9 to 21 , wherein the cleavable linker comprises at least one spacer unit, wherein the spacer unit attaches to the antibody or antigen-binding fragment via the maleimide (Mai) moiety ("Mal-spacer unit").

25. The antibody-drug conjugate of claim 24, wherein the Mal-spacer unit comprises a polyethylene glycol (PEG) moiety, wherein the PEG moiety comprises -(PEG)m- and m is an integer from 1 to 10.

26. The antibody-drug conjugate of claim 25, wherein m is 2, 3, or 4.

27. The antibody-drug conjugate of claim 24, wherein the Mal-spacer unit comprises an alkyl moiety, wherein the alkyl moiety comprises -(CH2)n- and n is an integer from 1 to 10, optionally wherein n is 5.

28. The antibody-drug conjugate of claim 24, wherein the Mal-spacer unit comprises C229. The antibody-drug conjugate of claim 24, wherein the Mal-spacer unit comprises C2(PEG)mwherein m is an integer from 0 to 4.

30. The antibody-drug conjugate of claim 29, wherein m is 1, 2, or 3.

31. The antibody-drug conjugate of claim 29 or claim 30, wherein the Mal-spacer unit comprisesC2(PEG)232. The antibody-drug conjugate of any one of claims 24 to 31, wherein the cleavable linker comprises the Mal-spacer unit and the cleavable peptide moiety.

33. The antibody-drug conjugate of claim 32, wherein the Mal-spacer unit attaches the antibody or antigen-binding fragment to the cleavable peptide moiety in the linker.

34. The antibody-drug conjugate of claim 32 or claim 33, wherein the Mal-spacer unit comprises Mal-(PEG)2-Val-Cit, Mal-(PEG)3-Val-Cit, Mal-(PEG)4-Val-Cit, Mal-(PEG)2-Val-Lys(Me)2,Mal- (PEG)2-Ala-Lys(Me)2, Mal-(PEG)2-Val-Ala, Mal-(PEG)2-Asn, Mal-(PEG)2-Asp, Mal-(PEG)2- Asp(OMe), Mal-C2(PEG)m-Val-Cit, Mal-C2(PEG)m-Val-Lys(Me)2, Mal-C2(PEG)m-Val-Ala(Me)2, Mal-C2(PEG)m-Val-Ala, Mal-C2(PEG)m-Asn, Mal-C2(PEG)m-Asp, or Mal-C2(PEG)m-Asp(OMe); wherein m is an integer from 0 to 4.

35. The antibody-drug conjugate of claim 34, wherein m is 2.

36. The antibody-drug conjugate of any one of claims 12 to 35, wherein the cleavable moiety in the linker is directly joined to the cytotoxic agent, or a spacer unit attaches the cleavable moiety in the linker to the cytotoxic agent.

37. The antibody-drug conjugate of claim 36, wherein the spacer unit attaching the cleavable moiety in the linker to the cytotoxic agent is self-immolative.

38. The antibody-drug conjugate of claim 36 or claim 37, wherein the spacer unit attaching the cleavable moiety in the linker to the cytotoxic agent comprises a p-aminobenzyloxycarbonyl (pABC).

39. The antibody-drug conjugate of claim 38, wherein the pABC attaches the cleavable moiety in the linker to the cytotoxic agent.

40. The antibody-drug conjugate of claim 39, wherein the cytotoxic agent is eribulin and the pABC covalently attaches to eribulin via a C-35 amine.

41. The antibody-drug conjugate of any one of claims 36 to 40, wherein the cleavable moiety comprises Val-Cit, Val-Ala, Val-Lys(Me)2, Ala-Lys(Me)2, Asn, Asp, or Asp(OMe).

42. The antibody-drug conjugate of claim 41 , wherein the cleavable linker comprises Val-Cit- pABC, Val-Ala-pABC, Val-Lys(Me)2-pABC, or Ala-Lys(Me)2-pABC.

43. The antibody-drug conjugate of claim 24, wherein the cleavable linker comprises DTM-Asn, Mal-(PEG)2-Val-Cit-pABC, Mal-(PEG)3-Val-Cit-pABC, Mal-(PEG)4-Val-Cit-pABC, Mal-(PEG)2-Val-Lys(Me)2-pABC, Mal-(PEG)2-Ala-Lys(Me)2-pABC, Mal-(PEG)2-Val-Ala-pABC, Mal-(PEG)2- Asn, Mal-(PEG)2-Asp, Mal-(PEG)2-Asp(OMe), Mal-C2(PEG)m-Val-Cit-pABC, Ma1-C2(PEG)m-Val- Lys(Me)2-pABC, Mal-C2(PEG)m-Val-Ala(Me)2-pABC, Mal-C2(PEG)m-Val-Ala-pABC, Mal- C2(PEG)m-Asn, Mal-C2(PEG)m-Asp, or Mal-C2(PEG)m-Asp(OMe); wherein m is an integer from O to 4.

44. The antibody-drug conjugate of claim 43, wherein the cleavable linker comprises Mal- (PEG)2-Val-Cit-pABC, Mal-(PEG)2-Val-Ala-pABC, Mal-(PEG)2-Asn, MaJ-C2(PEG)m-Val-Cit- pABC, Mal-C2(PEG)m-Val-Ala-pABC, or Mal-C2(PEG)m-Asn; wherein m is an integer from 1 to 3.

45. The antibody-drug conjugate of claim 43 or claim 44, wherein m is 2.

46. The antibody-drug conjugate of any one of claims 9 to 45, wherein the antibody or antigenbinding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system.

47. The antibody-drug conjugate of any one of claims 9 to 45, wherein the antibody or antigenbinding fragment comprises three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system.

48. The antibody-drug conjugate of claim 46 or claim 47, wherein the antibody or antigenbinding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

49. The antibody-drug conjugate of claim 46 or claim 47, wherein the antibody or antigenbinding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

50. The antibody-drug conjugate of claim 48, wherein the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

51. The antibody-drug conjugate of claim 49, wherein the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

52. The antibody-drug conjugate of claim 49, wherein the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

53. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Val-Cit-pABC; and p is an integer from 1 to 8.

54. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Val-Cit-pABC; and p is an integer from 1 to 8.

55. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)i-Val-Ala-pABC; and p is an integer from 1 to 8.

56. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Val-Ala-pABC; and p is an integer from 1 to 8.

57. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Asn; and p is an integer from 1 to 8.

58. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-(PEG)2-Asn; and p is an integer from 1 to 8.

59. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Val-Cit-pABC, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

60. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Val-Cit-pABC, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

61. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Val-Ala-pABC, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

62. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Val-Ala-pABC, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

63. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 3 (HCDR2), and SEQ ID NO: 4 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 8 (LCDR1), SEQ ID NO: 9 (LCDR2), and SEQ ID NO: 10 (LCDR3), as defined by the Kabat numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Asn, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

64. An antibody-drug conjugate of Formula (I):Ab-(L-D)p(I) wherein Ab is an anti-TROP2 antibody or antigen-binding fragment thereof comprising three HCDRs comprising amino acid sequences of SEQ ID NO: 11 (HCDR1), SEQ ID NO: 12 (HCDR2), and SEQ ID NO: 13 (HCDR3); and three LCDRs comprising amino acid sequences of SEQ ID NO: 15 (LCDR1), SEQ ID NO: 16 (LCDR2), and SEQ ID NO: 17 (LCDR3), as defined by the IMGT numbering system;D is eribulin;L is a cleavable linker comprising Mal-C2(PEG)m-Asn, wherein m is an integer from 0 to 4; and p is an integer from 1 to 8.

65. The antibody-drug conjugate of any one of claims 53 to 64, wherein m is 2.

66. The antibody-drug conjugate of any one of claims 53 to 65, wherein the antibody or antigenbinding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 175, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

67. The antibody-drug conjugate of any one of claims 53 to 65, wherein the antibody or antigenbinding fragment comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 55, and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 66.

68. The antibody-drug conjugate of claim 66, wherein the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 181 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

69. The antibody-drug conjugate of claim 66, wherein the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 380 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

70. The antibody-drug conjugate of claim 67, wherein the antibody or antigen-binding fragment comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 100 and a light chain comprising an amino acid sequence of SEQ ID NO: 115.

71. The antibody-drug conjugate of any one of claims 53 to 70, wherein p is 2.

72. The antibody-drug conjugate of any one of claims 9 to 71 , wherein p is determined by hydrophobic interaction chromatography-high performance liquid chromatography (HIC-HPLC) or reverse-phase liquid chromatography-mass spectrometry (LC-MS).

73. The antibody-drug conjugate of any one of claims 9 to 72, wherein the cytotoxic agent is eribulin and the cleavable linker covalently attaches to the eribulin via a C-35 amine.

74. The antibody-drug conjugate of any one of claims 9 and 53 to 73, wherein the cleavable linker covalently attaches to the antibody or antigen-binding fragment via a cysteine or a lysine.

75. A composition comprising multiple copies of the antibody-drug conjugate of any one of claims 9 to 74, wherein the average p of the antibody-drug conjugates in the composition is about 1 to about 3.

76. The composition of claim 75, wherein the average p is about 2.

77. One or more nucleic acid(s) encoding the antibody or antigen-binding fragment of any one of claims 1 to 7.

78. A host cell comprising the one or more nucleic acid(s) of claim 77.

79. A method of producing an antibody or antigen-biding fragment of any one of claims 1 to 7, comprising culturing the host cell of claim 78 under conditions sufficient to produce the antibody or antigen-binding fragment.

80. A method of producing the antibody-drug conjugate of any one of claims 9 to 74 or the composition of claim 75 or claim 76, comprising reacting an antibody or antigen-binding fragment of any one of claims 1 to 7 with a cleavable linker joined to eribulin under conditions that allow conjugation.

81. A compound of Formula (Ila):, wherein:D is a cytotoxic agent;Y is a cleavable moiety; andZ is absent or a spacer unit.

82. The compound of claim 81 , wherein the cytotoxic agent comprises eribulin or a salt thereof.

83. The compound of claim 81 or claim 82, wherein the cleavable moiety comprises a cleavable peptide moiety, optionally wherein the cleavable peptide moiety is cleavable by an enzyme; further optionally wherein the cleavable peptide moiety is cleavable by cathepsin or legumain, optionally wherein the cleavable peptide moiety is cleavable by cathepsin B.

84. The compound of claim 83, wherein the cleavable peptide moiety comprises an amino acid unit.

85. The compound of claim 84, wherein the amino acid unit comprises valine-citrulline (Val-Cit), valine-dimethylated lysine (Val-Lys(Me)2), alanine-dimethylated lysine (Ala-Lys(Me)2), valinealanine (Vai-Ala), asparagine (Asn), aspartic acid (Asp), or methylated aspartic acid (Asp(OMe)).

86. The compound of claim 85, wherein the amino acid unit comprises Val-Cit or Val-Ala.

87. The compound of claim 85, wherein the amino acid unit comprises Asn or Asp.

88. The compound of any one of claims 81 to 85 and 87, wherein Z is absent and the cleavable moiety is directly joined to the cytotoxic agent.

89. The compound of any one of claims 81 to 86, wherein Z is a spacer unit which attaches the cleavable moiety to the cytotoxic agent.

90. The compound of claim 89, wherein the spacer unit attaching the cleavable moiety to the cytotoxic agent is self-immolative.

91. The compound of claim 89 or claim 90, wherein the spacer unit attaching the cleavable moiety to the cytotoxic agent comprises a p-aminobenzyloxycarbonyl (pABC).

92. The compound of claim 91 , wherein the cytotoxic agent is eribulin, and the pABC covalently attaches to eribulin via a C-35 amine.

93. The compound of claim 91 or claim 92, wherein -Y-Z- comprises Val-Cit-pABC, Val-Ala- pABC, Val-Lys(Me)2-pABC, or Ala-Lys(Me)2-pABC.

94. The compound of any one of claims 81 to 85, wherein -Y-Z- comprises Val-Cit-pABC, Val- Ala-pABC, or Asn.

95. A pharmaceutical composition comprising the antibody or antigen-binding fragment of any one of claims 1 to 8, the antibody-drug conjugate of any one of claims 9 to 74, the composition of claim 75 or claim 76, or the compound of any one of claims 81 to 94; and a pharmaceutically acceptable carrier.

96. A method of treating a patient having or at risk of having a cancer that expresses TROP2, comprising administering to the patient a therapeutically effective amount of the antibody or antigenbinding fragment of any one of claims 1 to 8, the antibody-drug conjugate of any one of claims 9 to 74, the composition of claim 75 or claim 76, the compound of any one of claims 81 to 94, or the pharmaceutical composition of claim 95.

97. The method of claim 96, wherein the TROP2-expressing cancer is a cholangiocarcinoma, bladder cancer, breast cancer, cervical carcinoma, colorectal cancer, esophageal cancer, gastric cancer, glioma, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, or skin cancer; optionally wherein the TROP2-expressing cancer is a cholangiocarcinoma, breast cancer, or NSCLC.

98. A method of reducing or inhibiting growth of a TROP2-expressing tumor, comprising administering to the patient a therapeutically effective amount of the antibody or antigen-binding fragment of any one of claims 1 to 8, the antibody-drug conjugate of any one of claims 9 to 74, the composition of claim 75 or claim 76, the compound of any one of claims 81 to 94, or the pharmaceutical composition of claim 95.

99. The method of claim 98, wherein the tumor is a TROP2-expressing cholangiocarcinoma, bladder cancer, breast cancer, esophageal cancer, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, or skin cancer; optionally wherein the tumor is a cholangiocarcinoma.

100. Use of the antibody or antigen-binding fragment of any one of claims 1 to 8, the antibodydrug conjugate of any one of claims 9 to 75, the composition of claim 75 or claim 76, the compound of any one of claims 81 to 94, or the pharmaceutical composition of claim 95 in the manufacture of a medicament for the treatment of a TROP2-expressing cancer.

101. Use of an antibody or antigen-binding fragment of any one of claims 1 to 8, an antibody-drug conjugate of any one of claims 9 to 75, a composition of claim 75 or claim 76, a compound of any one of claims 81 to 95, or a pharmaceutical composition of claim 95 in the treatment of a TROP2- expressing cancer.

102. The use of claim 100 or claim 101, wherein the TROP2-expressing cancer is a cholangiocarcinoma, bladder cancer, breast cancer, esophageal cancer, hepatocellular carcinoma, nasopharyngeal cancer, non-small cell lung cancer (NSCLC), pancreatic cancer, endometrial cancer, ovarian cancer, or skin cancer; optionally wherein the TROP2-expressing cancer is a cholangiocarcinoma.