Engineered trop2 / nectin4 dual binding antibodies and uses thereof

Abstract

Described herein are anti-Trop2 / Nectin-4 dual binding antibodies and dual binding fragments thereof. Specific binding properties were demonstrated as monoclonal bivalent IgG antibodies and as immune-engager antibodies. An immune cell engager including the dual binding antibodies facilitated T cell activation and cytotoxicity toward tumor cells. The engineered anti-Trop2 / Nectin-4 dual antibodies may be used as part of a therapeutic approach to treat solid cancers and hemopoietic malignancies.

Description

ENGINEERED TROP2 / NECTIN4 DUAL BINDING ANTIBODIES AND USES THEREOFSEQUENCE LISTING STATEMENT

[0001] The instant application contains a Sequence Listing which has been submitted electronically in XML file format and is hereby incorporated by reference in its entirety. Said XML copy, created on May 27, 2025, is named P-637541 -PC_SL.xml and is 8843,500 bytes in size.BACKGROUND

[0002] Trop2 (Trophoblast cell-surface antigen 2) is a 36 kDa transmembrane glycoprotein encoded by tumor-associated calcium signal transducer 2 (TACSTD2) gene located in chromosome 1p32.

[0003] Since the discovery of Trop2 in the placenta, accumulating evidence suggests that T rop2 may play a role in tumor development as being involved in several growth-stimulatory signaling pathways. Trop2 is upregulated in a variety of malignant tumors and participates in several oncogenic signaling pathways that lead to tumor development, invasion, and metastasis. In addition, overexpression of Trop2 correlates with poor prognosis in various solid tumors. Multiple studies have demonstrated overexpression of Trop2 in various tumor types, including triple-negative breast cancers (TNBC), non-small cell lung cancers (NSCLC) and others.

[0004] T rop2 is considered an attractive prognostic marker and a therapeutic target for the treatment of solid tumors. While there are numerous different anti-Trop2 antibodies in clinical trials, most are ADCs (antibody-drug conjugates). For example, the anti-Trop2 ADC Trodelvy® (Sacituzumab Govitecan) has been approved to treat metastatic or locally unresectable triple-negative breast cancer and hormone receptor (HR) positive / Her2 negative breast cancer.

[0005] Nectin-4 (Nectin cell adhesion molecule 4), also known as poliovirus receptor- like (PVRL4), is a type I transmembrane polypeptide member of the Nectin family. Nectin-4 is involved in cell adhesion through homophilic / heterophilic interplay. In addition, Nectin-4 was also found to play a role in enhancing cell motility and viability.

[0006] Nectin-4 is a 66 kDa protein, possessing a three-domain structure as follows: (1) theextracellular-domain, consisting of three conserved Ig-like loops (V-C-C domain; one IgV, and two IgC loops), (2) one transmembrane-domain, and (3) the cytoplasmic-domain containing an afadin-binding motif.

[0007] Nectin-4 was found to be overexpressed in several tumor types, including breast, lung, urothelial, colorectal, pancreatic, and ovarian cancer. In addition, the upregulation of Nectin-4 is an independent biomarker for overall survival in numerous cancer types.

[0008] Nectin-4 is a validated target for anti-cancer therapies, and the use of anti-Nectin-4 antibodies is proving to be promising. There are currently a wide variety of therapeutic antibodies in clinical trials, mostly ADCs, wherein one ADC-based treatment was approved for the treatment of patients with urothelial carcinoma- PADCEV® (Enfortumab Vedotin).

[0009] Trop2 and Nectin-4 are well-known Tumor-Associated Antigens (TAAs) with demonstrated effectiveness as immune-oncology targets in various indications, however, the diversity in antigen expression across tumor cells often limits the efficacy of these therapies. Therefore, their combined targeting could potentially enhance therapeutic efficacy.

[0010] Solid tumors represent a significant clinical challenge, characterized by their complexity and heterogeneity. Antibody-drug conjugates (ADCs), such as Trodelvy® (targeting Trop2) and Padcev® (targeting Nectin4), have shown promise in targeting tumor cells and delivering cytotoxic payloads directly to cancerous tissues. However, the diversity in antigen expression across tumor cells often limits the efficacy of these therapies.

[0011] Combining both targets has several advantages: it increases therapeutic efficacy by therapeutically targeting two different tumor-associated antigens expressed over the surface of the same cell; it therapeutically targets two different tumor associated antigens expressed over the surface of different cells; it addresses intra-tumoral heterogenicity targeting cells that express either Trop2 or Nectin-4, or both antigens together Trop2 and Nectin-4; it broadens the pool of potentially suitable patient populations, as Trop2 and Nectin-4 have only partial overlapping expression profile in some cancer patients; it broadens the pool of potentially suitable patient population, and increases the relevant indications as Trop2 and Nectin-4 have only partial overlapping expression profile in some cancer indications.

[0012] Additionally, targeting both antigens helps prevent tumor immune escape mechanisms, where tumor cells might downregulate one TAA to evade immune clearance.This dual-targeting strategy enables medical personnel to address a wider biological diversity among cancer patients and mitigate reduced efficacy due to antigenic drifting or antigen loss of a tumor, e.g., loss or reduction of antibody binding due to mutations of one or more amino acids (AAs) within the antigenic epitopes. This phenomenon poses a significant clinical concern, as it may result in lack of response to the targeted therapy, disease recurrence, and limited treatment options (Khoury et al., Mechanisms of Resistance to Antibody-Drug Conjugates. Int. J. Mol. Sci. 2023, 24, 9674. https: / / doi.org / 10.3390 / ijms24119674).

[0013] Trop2 / Nectin4 dual binding antibody technology addresses the issue of tumor diversity and heterogeneity and could allow targeting a large biologically diverse pool of cancer patients. Use of aTrop2 / Nectin4 dual binding antibody could also rescue and prevent reduced efficacy in case of antigenic drifting or antigen loss.

[0014] It has been suggested that combination therapies targeting Nectin-4 and Trop2 have an advantage over the single TAA targeting approach, as the administration of Sacituzumab Govitecan (Trodelvy®) and Enfortumab Vedotin (Padcev®) as a combination therapy, yielded 70% Objective Response Rates (ORR) in small phase 1 studies for the treatment of metastatic urothelial cancer resistant to platinum and immunotherapy. However, this combination treatment suffers from therapeutic and safety challenges. Firstly, the overlapping toxicities associated with ADCs can exacerbate adverse events, making it difficult to manage patient safety. Both Sacituzumab and Enfortumab are linked to significant side effects, such as neutropenia, fatigue, and peripheral neuropathy, which can be amplified when used together. Secondly, the risk of developing resistance mechanisms to two cytotoxic payloads increases with such combination therapies. Thirdly, pharmacokinetic interactions between the two ADCs can affect drug metabolism and clearance, potentially leading to suboptimal drug concentrations in the bloodstream. This can impact the overall effectiveness of the treatment and complicate dose optimization. Lastly, combination therapy may impose logistical challenges in clinical settings. Coordinating the administration schedules, monitoring for specific adverse events, providing treatment to address adverse events, and consulting on dose adjustment, delay or discontinuation based on individual patient responses require meticulous planning and resources.

[0015] Dual binding antibodies described herein provide advantages over the use of individual agents. Engaging two tumor associated antigens, e.g., Trop2 and Nectin-4, in asingle antibody unit increases efficacy. Targeting two TAAs, e.g., Trop2 and Nectin-4, with overlapping expression profiles on tumor cells, strengthens the attack on cancer cells. Dual binding antibodies reduce the probability of cells to escape by downregulation of TAAs and mitigates against resistance that stems from the heterogeneous expression of a single TAA. In addition, these dual binding antibodies broaden the target patient population and the span of relevant indications to include indications expressing either one of the TAAs or both, e.g., Trop2 and Nectin-4.

[0016] Dual binding antibodies disclosed herein also provide unique advantages for multibody format wherein a symmetrical IgG construct is produced, not as a bispecific construct, but as symmetrical IgG, where each arm is capable of targeting two different TAAs, retaining the full IgG’s bivalent avidity for each target. Thus, these dual binding antibodies, when in an IgG format, are uniquely suited to overcome target expression heterogeneity, since both arms can bind both targets. Moreover, maintaining the IgG format enables improved developability profile compared to a bispecific format.

[0017] Specifically, dual-binding antibodies (multibodies), being a standard, symmetrical IgG antibodies, are easier and less costly to produce due to their uniform structure, unlike the complex engineering required for chimeric bispecific antibodies. This simpler structure often results in higher yields and easier purification processes. Additionally, multibodies are generally more stable than chimeric bispecific antibodies, which might have issues with stability at their fusion points and mismatched heavy / light chains. Symmetrical IgG antibodies, such as multibodies, typically exhibit more predictable and favorable pharmacokinetic profiles, including longer half-lives and better biodistribution. Their simpler, more natural structure also tends to result in lower immunogenicity compared to chimeric bispecific antibodies, which may be recognized as foreign by the immune system. Using the same variable domain for both targets ensures homogeneous binding affinity and avidity, leading to more consistent therapeutic effects. Furthermore, multibodies avoid the risk of mispairing and incorrect assembly of heavy and light chains, a common issue with bispecific antibodies that can lead to lower yields and heterogeneous products. Overall, the simpler design, easier production, and purification processes, along with a lower risk of manufacturing issues and regulatory hurdles, make symmetrical IgG antibodies more cost- effective. These advantages make regular symmetrical IgG dual binder (multibody) a compelling choice in many therapeutic applications particularly when targeting two differenttargets is feasible and desirable.SUMMARY

[0018] In one aspect, described herein is an isolated Trop2 / Nectin-4 dual binding antibody comprising three heavy chain complementarity determining regions (CDRs) (HCDR1 , HCDR2, and HCDR3) and three light chain CDRs (LCDR1 , LCDR2, and LCDR3), wherein the amino acid sequences of HCDR1 , HCDR2 and HCDR3 comprise the amino acid sequences set forth in Table 3A and wherein the amino acid sequence of LCDR1 , LCDR2 and LCDR3 comprise the amino acid sequences set forth in Table 4A, and wherein the amino acid sequences for HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 are all selected from the same clone variant.

[0019] In a related aspect, an isolated Trop2 / Nectin-4 dual binding antibody comprises a heavy chain variable domain (VH) and a light chain variable domain (VL), said VH and VL comprising the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 regions, respectively, wherein the amino acid sequence of the VH and VL comprise the amino acid sequences set forth in Table 1 and Table 2, and wherein the amino acid sequences for VH and VL are selected from the same clone variant.

[0020] In another related aspect, an isolated Trop2 / Nectin-4 dual binding antibody disclosed herein, is in the form of an IgG, an Fv, an scFv, an Fab, a F(ab')2, a minibody, a diabody, a triabody, an immune-cell engager, a multi-specific antibody, or a multi-engager. In a further related aspect, an isolated Trop2 / N ectin-4 dual binding antibody is monovalent, bivalent, or multivalent. In another further related aspect, an isolated Trop2 / Nectin-4 dual binding antibody is multi-specific. In yet another further related aspect, an isolated Trop2 / Nectin-4 dual binding antibody, disclosed herein is formatted as an lgG1 , lgG2, lgG3, or lgG4.

[0021] In a related aspect, an isolated Trop2 / Nectin-4 dual binding antibody is unable to bind or has reduced binding to Fragment crystallizable gamma receptors (FcyRs), that mediate antibody-dependent cellular cytotoxicity (ADCC). In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody cannot trigger antibody-mediated effector functions, including but not limited to antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cellular toxicity (CDC). In a further related aspect of an isolated Trop2 / Nectin-4 dual bindingantibody, the antibody comprises a heavy chain comprising a mutation, wherein said mutation is a L234A L235A (LALA) mutation or a L234A L235A P329G (LAL PG) mutation.

[0022] In some aspects, an isolated Trop2 / Nectin-4 dual binding antibody or a dual binding fragment thereof cannot trigger antibody-mediated effector functions, including antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cellular toxicity (CDC).

[0023] In some embodiments, a dual binding antibody or a dual binding fragment thereof comprises a native Fc format.

[0024] In certain aspects, described herein are compositions comprising an isolated Trop2 / Nectin-4 dual binding antibody as disclosed and a pharmaceutically acceptable carrier.

[0025] In certain aspects, described herein are isolated polynucleotide constructs encoding a Trop2 / Nectin-4 dual binding antibody or binding fragments thereof. In a related aspect, an isolated polynucleotide construct encodes an isolated dual binding antibody, as disclosed herein. In another related aspect, an isolated polynucleotide construct encodes a Trop2 / Nectin-4 dual binding scFv antibody-binding fragment, wherein said polynucleotide encodes the VH and VL regions comprising the amino acid sequences as set forth in Table 1 and Table 2, and wherein the amino acid sequences for VH and VL are selected from the same clone variant. In yet another related aspect, an isolated polynucleotide construct encodes a Trop2 / Nectin-4 dual binding antibody, wherein said polynucleotide encodes the VH and VL regions comprising the amino acid sequences as set forth in Table 1 and Table 2, and wherein the amino acid sequences for VH and VL are selected from the same clone variant.

[0026] In another aspect, disclosed herein is an expression vector comprising the polynucleotide construct comprising a Trop2 / Nectin-4 dual binding antibody or a binding fragment thereof.

[0027] In still another aspect, disclosed here is a host cell comprising an expression vector comprising the polynucleotide construct comprising a Trop2 / Nectin-4 dual binding antibody or a binding fragment thereof.

[0028] In certain aspects, disclosed herein is a method of treating a subject suffering from a disease or condition, said method comprising administering to said subject a composition comprising an isolated Trop2 / Nectin-4 dual binding antibody as described herein. In arelated aspect, the disease or condition is cancer. In a further related aspect, a cancer comprises a solid tumor, a hematopoietic malignancy, or a metastatic cancer, or a combination thereof. In another further related aspect of a method of treating a subject in need, a solid tumor expresses Trop2 and Nectin-4 on its cell surface. In a further related other aspect, the tumor expresses Trop2 but not Nectin-4 on its cell surface. In yet another further related aspect, the tumor expresses Nectin-4 but not Trop2 on its cell surface.

[0029] In another aspect, there is provided an isolated Trop2 / Nectin-4 dual binding antibody, comprising three heavy chain complementarity determining regions (CDRs) (HCDR1 , HCDR2, and HCDR3) and three light chain CDRs (LCDR1 , LCDR2, and LCDR3), wherein the six CDRs are defined by a standard method selected from the group consisting of Chothia, Kabat, IMGT®, Paratome, and AbM, based on heavy chain variable domain (VH) and light chain variable domain (VL) amino acid sequences set forth in Table 1 and Table 2, respectively, wherein said VH comprises the three heavy chain CDRs and said VL comprises the three light chain CDRs, and wherein the amino acid sequences selected from Table 1 and Table 2 are from the same clone variant. In another related aspect, there is provided an isolated polynucleotide construct encoding a Trop2 / Nectin-4 dual binding antibody, wherein said polynucleotide encodes the CDRs as defined by such standard method.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The subject matter of engineered Trop2 / Nectin4 dual binding antibodies is particularly pointed out and distinctly claimed in the concluding portion of the specification. These dual binding antibodies, however, both as to their generation and method of use, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[0031] Fig. 1. Schematic representation of a dual binding antibody in the form of an IgG. Fig. 1 presents a schematic representation of a dual binding antibody in the form of an IgG, as embodied herein, that is designed to bind Trop2 and Nectin-4, wherein the binding to Trop2 and Nectin-4 within a Fv region is mutually exclusive. The binding is modulated by time, location, and target concentration. The dual binding IgG antibody can bind Trop2 with both arms; Nectin-4 with both arms; or Trop2 with one arm and Nectin-4 with a second arm.

[0032] Figs. 2A and 2B. Enriched populations from a yeast-displayed scFv library binding both Trop2 and Nectin-4. A yeast-displayed scFv library in advanced round of selections was analyzed for binding to (Fig. 2A) 1nM Trop2-His and (Fig. 2B) 1 nM Nectin- 4-His. Binding to His-tagged ligand was detected by Allophycocyanin (APC)-conjugated anti-His antibody and scFv expression was detected by FITC-conjugated anti-cMyc antibody. The X axis in each plot represents scFv expression and the Y axis represents binding signal. Lead Trop2 / Nectin-4 dual binder clones were isolated from this enriched population for further analysis.

[0033] Figs. 3A and 3B. Yeast-displayed control antibodies demonstrate specific binding to their respective antigens. The variable domain of a published anti-Trop2 antibody (Sacituzumab; Sacituzumab Trop2 variable domain: VH: Sequence 14 from patent US 9999668 and VL: Sequence 12 from patent US 9999668; Syed, Y. Y. “Sacituzumab Govitecan: First Approval” . Drugs 80, 1019-1025 (2020).) was used as a control and was evaluated as a yeast-displayed scFv for the binding of 1uM Nectin-4 or 1 nM Trop2 (Fig. 3A). Sacituzumab demonstrates strong, specific binding to its ligand T rop2 with no apparent binding to Nectin-4. The variable domain of a published anti-Nectin-4 antibody was used as a control (Enfortumab; Enfortumab Nectin4 variable domain: VH: taken from Sequence 7 from patent US 10894090 and VL: taken from Sequence 8 from patent US 10894090; Rosenberg, J. et al. “EV-101: A Phase I Study of Single-Agent Enfortumab Vedotin in Patients With Nectin-4-Positive Solid Tumors, Including Metastatic Urothelial Carcinoma." J. Clin. Oncol. Off. J. Am. Soc. Clin. Oncol. 38, 1041-1049 (2020)) and was evaluated as a yeast-displayed scFv for the binding of 5nM Nectin-4 or 1 uM Trop2 (Fig. 3B). Enfortumab demonstrates a strong, specific binding to its ligand Nectin-4 with no apparent binding to Trop2.

[0034] Figs. 4A and 4B. EC-50 binding assay of Trop2 / Nectin-4 variants. Isolated clones from an enriched yeast displayed scFv library were evaluated fortheir binding affinity to human Trop2 (hTrop2) and human Nectin-4 (hNectin-4) in an EC-50 binding assay. Tested clones were incubated with increasing concentrations of hTrop2-His (Fig. 4A) or Nectin-4-His (Fig. 4B). Binding to His-tagged ligand was detected by APC-conjugated anti- His antibody and scFv expression was detected by FITC-conjugated anti-cMyc antibody using flow cytometry. The X axis in each plot represents scFv expression and the Y axis represents binding signal.

[0035] Figs. 5A and 5B. Representative variant CID 1895 off target binding assay. Variant CID1895 antibodies formatted as scFv, were incubated with (Fig. 5A) 300nM hTROP1-Fc (Fig. 5A) and 500nM Nectin1-3-His mix (Fig. 5B). CID1895 scFv antibodies were screened after labeling using Cytoflex. A yeast displayed scFv representative clone (CID1895) was evaluated for specific binding properties. The tested clone was incubated with human Trop2 homolog protein, human Trop1-Fc protein, or with a mixture of human Nectin-4 homolog proteins, human Nectin1-His, human Nectin-2-His, and human Nectin-3- His. Binding to His-tagged ligand was detected by A PC-conjugated anti-His antibody, binding to Fc-tagged ligand was detected by PE-conjugated anti-Fc antibody, and scFv expression was detected by FITC-conjugated anti-cMyc antibody using flow cytometry. The X axis in each plot represents scFv expression and the Y axis represents binding signal.

[0036] Figs. 6A-6M. Representative Trop2 / Nectin-4 Dual binding antibody clones CID1895, CID2821, CID2822, and CID2040 in an IgG format, bind human Trop2 and cynomolgus Trop2 and human Nectin-4 and cynomolgus Nectin-4 with similar affinities. Representative Trop2 / Nectin-4 Dual binding antibody clones do not bind human paralogues of Trop2 and Nectin-4. Figs. 6A-6H present the binding kinetics of an IgG formatted representative Tro p2 / N ectin-4 dual binding antibody (clone Cl D1895), anti- Trop2 control antibody in lgG1 format (Sacituzumab), and anti-Nectin-4 control antibody in lgG1 format (Enfortumab) to human Trop2, cynomolgus Trop2, human Nectin-4 and cynomolgus Nectin-4. Binding was assessed using Surface Plasmon Resonance (SPR). T rop2 / Nectin-4 dual antibody Cl D1895 binds human T rop2 (Fig. 6A) and cynomolgus T rop2 (Fig. 6B) with similar binding kinetics, and human Nectin-4 (Fig. 6E) and cynomolgus Nectin-4 (Fig. 6F) with similar kinetics. Anti-Trop2 control antibody (Sacituzumab) shows similar-cross species binding affinities between human Trop2 and cynomolgus Trop2 (Figs. 6C-D). Anti-Nectin-4 control (Enfortumab) antibody shows similar-cross species binding between human Nectin-4 and cynomolgus Nectin-4 (Figs. 6G-H). Sensogram traces and calculated binding kinetics of a CM5 chip-bound tested antibodies and soluble tested antigens serving as analytes. Surface plasmon resonance (SPR) analysis was performed to calculate the kinetics of binding for clone BDG2.182 (CID2822 in hl gG 1 format) to human and cyno Trop2 and Nectin-4 (Fig. 6I against human Trop2 and Fig. 6J against cyno Trop2; Fig. 6K against human Nectin-4 and Fig. 6L against cyno Nectin-4) using Biacore S200. To assess non-specific binding, ELISA binding was performed to determine the binding ofclones BDG2.121 (CID2040 in the hlgG1 LALA format), BDG2.184 (CID2821 in the hlgG1 format), and BDG2.182 (CID2822 in the hlgG1 format) to recombinant human Trop2 paralogue, epithelial-specific cell adhesion molecule / Trop1 (EpCAM), and human Nectin-4 related paralogs, Nectin-1 , Nectin-2, and Nectin-3 (Fig. 6M). Control antibodies Sacituzumab and Enfortumab would show a similar lack of binding to Trop2 and Nectin-4 paralogs (Data not shown). All antibodies tested were formatted as hlgG1 antibodies.

[0037] Figs. 7A, 7B, and 7C. Trop2 / Nectin-4 dual antibody (CID1895) binds both human Nectin-4 and human Trop2 in a CD3-BiTE® (Multi-specific T cell Engager) format. Tested antibodies were produced as a BiTE® molecule consisting of two scFvs connected by a short peptide linker. The variable domains of CID1895, Sacituzumab, and Enfortumab were each constructed as a scFv and were each separately fused to a scFv comprising the variable domain of a published anti-CD3 antibody derived from an approved T-cell engager (pacanalotamab; Pacanalotamab anti-CD3 binding variable domain: VH and VL: Sequence 340 from US 10766969; Hipp, S. et al. A novel BCMA / CD3 bispecific T-cell engager for the treatment of multiple myeloma induces selective lysis in vitro and in vivo. Leukemia 31, 1743-1751 (2017)) in a BiTE® format. Binding was analyzed using an Enzyme-Linked Immunosorbent Assay (ELISA). Binding EC-50 of Cl D1895 in a BiTE format (BDB2.004) was compared to Sacituzumab and to Enfortumab controls in the same BiTE format (BDB2.010 and BDB2.017, respectively). While CID 1895, in a BiTE format (BDB2.004) shows binding to both human Trop2 and human Nectin-4, the control antibodies Sacituzumab (BDB2.010), and Enfortumab (BDB2.017) exhibit specific binding to either human Trop2 or to human Nectin-4, respectively (Figs. 7A-7B). Fig. 7C presents the tabulated results. 96 well plates were coated with human Trop2 or human Nectin-4 (50ng / well) and incubated with increasing concentrations of the tested antibodies. Binding assays were done in duplicate; error bars represent standard deviations. The key presented in Fig. 7B is for Fig. 7A as well.

[0038] Figs. 8A and 8B. Binding results of Control Antibodies in a CD3-BiTE® (MultiEngager) format. Tested antibodies were produced as a BiTE® molecule consisting of two scFvs connected by a short peptide linker. The variable domains of CID1895, Sacituzumab, and of a non-binding control (NBC; targets a targeting viral epitope of RSV, B21m anti RSV: VH: Sequence 49 from US 20060159695_A1 and VL: Sequence 51 from US 20060159695_A1; Canziani, G. A., Melero, J. A. & Lacy, E. R. Characterization ofneutralizing affinity-matured human respiratory syncytial virus F binding antibodies in the sub-picomolar affinity range. J. Mol. Recognit. JMR 25, 136-146 (2012)) antibody were each constructed as a scFv and were each separately fused to a scFv comprising of the variable domain of a published anti-CD3 antibody derived from an approved T-cell engager (pacanalotamab; Pacanalotamab anti-CD3 binding variable domain taken from: Sequence 340 from US 10766969) in a BiTE® format. CID1895 BiTE® (BDB2.004) demonstrates T cell activation following engagement to both Trop2 and Nectin-4 expressing cell lines, while the control antibody Sacituzumab BiTE (BDB2.010) showed T cell activation following engagement to Trop2 cells only. The NBC BiTE (BDB100.006) did not show T cells activation, as expected. Jurkat-NFAT-luciferase reporter cells were incubated with HEK293- Trop2 (Fig. 8A) or HEK293- Nectin-4 (Fig. 8B) cells at an effector-to-target ratio of 3:1. Cells were incubated with increasing concentrations of the tested antibodies for 24h. Luciferase levels were measured as an indication of T-cells NFAT activation.

[0039] Figs. 9A and 9B. BDB2.004 demonstrates T cell-directed specific killing to both Trop2 and Nectin-4 expressing cell lines. Tested antibodies were produced as a BiTE® molecule consisting of two scFvs connected by a short peptide linker. The variable domains of Cl D1895, Sacituzumab, and of a non-binding control (NBC) antibody were each constructed as a scFv and were each separately fused to a scFv comprising of the variable domain of a published anti-CD3 antibody derived from an approved T-cell engager (pacanalotamab) in a BiTE® format. hPBMCs were co-cultured with either (Fig. 9A) HEK293 Trop2 or (Fig. 9B) HEK293 Nectin-4 expressing cell lines for 48h in the presence of increasing concentrations of the tested antibodies. Cytotoxicity percentage was defined as Lactate dehydrogenase (LDH) secreted levels of treated samples relative to maximal LDH secretion.

[0040] Figs. 10A and 10B. BDB2.004 mediates high secretion level of IFN-y (IFN- gamma) upon killing of both Trop2 and Nectin-4 expressing cell lines. Tested antibodies were produced as a BiTE® molecule consisting of two scFvs connected by a short peptide linker. The variable domains of CID1895, Sacituzumab, and of a non-binding control (NBC) antibody were each constructed as a scFv and were each separately fused to a scFv comprising of the variable domain of a published anti-CD3 antibody derived from an approved T-cell engager (pacanalotamab) in a BiTE® format. hPBMCs were co-cultured with either (Fig. 10A) HEK293 Trop2 or (Fig. 10B) HEK293 Nectin-4 expressing cell linesfor 48h. The cells were treated with increasing concentrations of the tested antibodies. IFN- Y (IFN-gamma) concentration (pg / ml) was defined by ELISA assay as described in Examples.

[0041] Figs. 11A-11C. Representative Trop2 / Nectin-4 dual antibody (CID1895) binds both human Nectin-4 and human Trop2 in a DuoBody® format. Tested antibodies were produced as an IgG like T-cells engager in a DuoBody® (Genmab) format. The DuoBody® format consists of two arms, where one arm comprises the variable domain of a published anti-CD3 antibody derived from an approved T-cell engager (pacanalotamab) and the second arm comprises the variable domains of CID1895, or of Sacituzumab, or of Enfortumab, or of a non-binding control (NBC) antibody. Dual specificity binding of CID1895 in a DuoBody® format (BDB2.012) for human Trop2 (Fig. 11 A) and human Nectin-4 (Fig. 11B) was demonstrated using Enzyme-Linked Immunosorbent Assay (ELISA). Binding EC- 50 of CID1895-DuoBody® (BDB2.012) was compared to the Sacituzumab- DuoBody® (BDD2.014) and to Enfortumab-DuoBody® (BDD2.019) controls in the same DuoBody® format. While CID 1895- Duo Body® (BDB2.012) shows binding to both human Trop2 and human Nectin-4, Sacituzumab-DuoBody® (BDD2.014), and Enfortumab-DuoBody® (BDD2.019) controls exhibited specific binding to either human Trop2 or to human Nectin- 4, respectively. Tabulated data is presented in Fig. 11C. 96 well plates were coated with human Trop2 or human Nectin-4 (50ng / well) and incubated with increasing concentrations of the tested antibodies. Binding assays were done in duplicate; error bars represent standard deviations.

[0042] Figs. 12A-12C. Trop2 / Nectin-4 dual DuoBody® demonstrates T cell activation following specific engagement to both Trop2 & Nectin-4 expressing cell lines. Tested antibodies were produced as an IgG like T-cells engager in a DuoBody® format. The Duobody® format consists of two arms, where one arm comprises the variable domain of a published anti-CD3 antibody derived from an approved T-cell engager (pacanalotamab) and the second arm comprise of the variable domain of CID1895, or of Sacituzumab, or of Enfortumab, or of a non-binding control (NBC) antibody Jurkat-NFAT- luciferase reporter cells were incubated with target cells at an effector-to-target ratio of 3:1 in the presence of serially diluted DuoBody® of the tested antibodies. Cells were incubated for24h with (Fig. 12A) HEK293 Trop2, (Fig. 12B) HEK293 Nectin-4 or 48h with MCF7 (Fig. 12C). Luciferase levels were measured as indication for T-cells NFAT activation.

[0043] Figs. 13A and 13B. BDD2.012 demonstrates T cell-directed specific killing of both Trop2 and Nectin-4 expressing cell lines. hPBMCs were co-cultured with either (Fig. 13A) HEK293 Trop2 or (Fig. 13B) HEK293 Nectin-4 expressing cell lines for 48h. Cytotoxicity percentage was defined as LDH secreted levels of treated samples relative to maximal LDH secretion. NBC= non-binding control.

[0044] Figs. 14A and 14B. BDD2.012 mediates high secretion level of IFN-y (IFN- gamma) upon killing of both Trop2 and Nectin-4 expressing cell lines. hPBMCs were co-cultured with either (Fig. 14A) HEK293 Trop2 or (Fig. 14B) HEK293 Nectin-4 expressing cell lines for 48h. The cells were treated with various concentrations of the BDD2.012 and NBCxCD3. IFN-y (IFN-gamma) concentration (pg / ml) was defined by ELISA assay as described in Examples. NBC= non-binding control.

[0045] Figs. 15A-15D. Representative Trop2 / Nectin-4 dual binding antibodies BDG2.144 (CID2040; hlgG1), BDG2.182 (CID2822; hlgG1), and BDG2.201 (CID2822 in hlgG1 format with LALA) demonstrate superior antibody cell internalization characteristics in T47D breast cancer cells, compared to Sacituzumab and Enfortumab. T47D breast cancer cells expressing Trop2 and Nectin-4 were incubated with representative Trop2 / Nectin-4 dual binding antibodies and control antibodies precomplexed with Incucyte® Fabfluor-pH Antibody Labeling Reagent, and internalization of the antibodies into the cells was assessed. Tested antibodies included dual binding antibodies and mono-targeting control antibodies Sacituzumab and Enfortumab-. Imaging was captured at the indicated time points (X-axis) by the Incucyte® Live-Cell Analysis System (Sartorius, Germany) and internalization intensity and area (Y-axis) were assessed using the IncuCyte® software. Fig. 15A and Fig. 15C show analysis of antibodies’ internalization by area indicating total antibody internalized into the cell. Fig. 15B and Fig. 15D show analysis of antibody internalization by signal intensity, indicating the antibody’s internalization to the endocytic vesicles and lysosomes. NBC - non-binding control.

[0046] Figs. 16A-16B. Representative Trop2 / Nectin-4 dual antibodies BDG2.1 4 (CID2040; IgG ID), BDG2.182 (CID2822; IgG ID), and BDG2.201 (CID2822 in hlgG1 format with LALA) demonstrate a higher dose-dependent level of cell internalization in T47D breast cancer cells, compared to Sacituzumab and Enfortumab antibodies. T47D breast cancer cells were incubated for 24 hours at 37°C with increasing concentrations of representative labeled antibodies (ranging from 0.03 to 3 pg / ml). Prior toincubation with the cells, the tested antibodies were complexed with the Fabfluor-pH antibody labeling reagent at a molar ratio of 1 antibody:3 reagent. Antibody internalization was measured by calculating the fluorescence intensity per cell area over time using IncuCyte® live imaging and its designated software. NBC - non-binding control.

[0047] Figs. 17A and 17B. Representative Trop2 / Nectin-4 dual binding antibody BDG2.201 (CID2822 in hlgG1 format with LALA) demonstrate superior antibody cell internalization characteristics, compared to Sacituzumab and Enfortumab in SK-BR- 3 breast cancer cells. Fig. 17A shows analysis of antibody’s internalization by area indicating total antibody internalized into the cell. Fig. 17B shows analysis of antibody internalization by signal intensity, indicating the antibody’s internalization to the endocytic vesicles and lysosomes. Methodology of internalization levels and kinetics of dual binding antibodies into SK-BR-3 cells were as described for T47D cells in Figs. 15A-15D.

[0048] Fig. 18. Representative Trop2 / Nectin-4 Dual Binding Antibody BDG2.201 (CID2822 in hlgG1 format with LALA) demonstrated a higher dose-dependent level of cell internalization, compared to Sacituzumab and Enfortumab control antibodies in SK-BR-3 breast cancer cells. Dose-dependent internalization methodology of dual binding antibodies into SK-BR-3 cells as described for T47D cells in Figs. 16A-16B.DETAILED DESCRIPTION

[0049] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the engineered Trop2 / Nectin-4 dual binding antibodies disclosed herein, including a description of their heavy chain and light chain variable regions. However, it will be understood by those skilled in the art that preparation and use of Trop2 / Nectin-4 dual binding antibodies may, in certain cases, be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the disclosure presented herein.

[0050] As used herein, the terms “Trop2” and “Trop-2” may be used interchangeably having all the same meanings and qualities. Similarly, the terms “Nectin-4” and “Nectin4” may be used interchangeably, having all the same meanings and qualities.

[0051] In some embodiments, the present disclosure describes the making and uses of engineered antibodies, designed by leveraging Al and that would confer binding specificityto Trop2 and Nectin-4. In certain embodiments, the present disclosure describes the use of engineered Trop2 / Nectin-4 dual binding antibodies for treating cancers, including solid tumors, hematopoietic malignancies, and metastatic cancer. In some embodiments, the dual binding antibodies described here are used for treating solid cancer. In some embodiments, the dual binding antibodies described here are used for treating hematopoietic malignancies. In some embodiments, the dual binding antibodies described here are used for treating metastatic cancer. In some embodiments, the dual binding antibodies described here are used for treating unresectable cancer. In some embodiments, the dual binding antibodies described here may be used for treating cancer. In some embodiments, the dual binding antibodies described here may be used for treating a cancer that expresses Trop2 and Nectin-4 on its cell surface. In some embodiments, this may be advantageous in cancers expressing both Trop2 and Nectin-4 on their cell surface, e.g., bladder cancer or urothelial carcinoma, whereas the corresponding healthy tissue expresses minimal Trop2 and Nectin-4 on their surface. In some embodiments, the Trop2 / Nectin-4 dual binding antibodies are used for treating bladder cancer. In some embodiments, the Trop2 / Nectin-4 dual binding antibodies are used for treating urothelial carcinoma.

[0052] Antigen binding sequences are conventionally located within the heavy chain and light chain variable region sequences of an antibody. These heavy and light chain variable regions may, in certain instances, be manipulated to create new binding sites, for example to create antibodies or fragments thereof, that bind to a different antigen or an epitope of a different antigen thereof. In some embodiments, as described herein, manipulating the sequence of a heavy chain variable region or the sequence of a light chain variable region, or both, creates a new binding site for an epitope while maintaining antibody original functionality. In some embodiments, specific sites within the heavy and light chain variable regions are identified, wherein the presence of variant amino acids at these sites, in certain embodiments, creates an engineered dual binding antibody or fragment thereof. In some embodiments, the potential variant sites provide a unique platform from which to engineer dual binding antibodies or fragments thereof.

[0053] Disclosed herein are engineered Trop2 / Nectin-4 dual binding antibodies or fragments thereof. In some embodiments, these engineered Trop2 / Nectin-4 dual binding antibodies may be identified and selected from a library. These dual binding antibodies mayexist in various forms or having various domains including, without limitation, a complementarity determining region (CDR), a variable region (Fv), a VH domain, a VL domain, a single chain variable region (scFv), and a Fab fragment.

[0054] A skilled artisan would appreciate that for an isolated Trop2 / Nectin-4 dual binding antibody disclosed herein, comprising three heavy chain complementarity determining regions (CDRs) (HCDR1, HCDR2, and HCDR3) and three light chain CDRs (LCDR1 , LCDR2, and LCDR3), the six CDRs may in some embodiments, be defined by a standard method selected from the group consisting of Chothia, Kabat, IMGT®, Paratome, and AbM, in view of the amino acid sequences of the respective heavy chain variable domain (VH) and light chain variable domain (VL) amino acid sequences of these antibodies, as set forth in Table 1 and Table 2, respectively, wherein said VH comprises the three heavy chain CDRs and said VL comprises the three light chain CDRs, and wherein the amino acid sequences selected from Table 1 and Table 2 are from the same clone variant. In some embodiments, the six CDR sequences may be defined by methods known in the art, for example but not limited to Chothia, Kabat, IMGT®, Paratome, and AbM schemes of defining CDR sequences.

[0055] The annotation of CDRs by the IMGT® numbering scheme was developed by Lefranc et al. (2003) “IMGT unique numbering for immunoglobulin and T cell receptor variable domains and Ig superfamily V-like domains." Dev Comp Immunol. 27: 55-77. One skilled in the art would know how to use this approach, as applied with various tools, for example but not limited to, ANARCI (Dunbar and Deane (2016) “ANARCI: antigen receptor numbering and receptorclassification." Bioinformatics, Volume 32, Issue 2, Pages 298-300) and AbRSA (Li et al. (2019) “AbRSA: A robust tool for antibody numbering". Protein Sci. 2019 Aug;28(8): 1524- 1531). The skilled artisan would also know how to use the Kabat, Chothia, and or AbM numbering schemes as applied with various tools, as described in at least Wu TT, Kabat EA. (1970) “An analysis of the sequences of the variable regions of Bence Jones proteins and myeloma light chains and their implications for antibody complementarity." J Exp Med. 132(2) :211-50; Al-Lazikani B, Lesk AM, Chothia C. (1997) “Standard conformations for the canonical structures of immunoglobulins." J Mol Biol. ;273(4):927-48; and Abhinandan KR, and Martin AC. (2008) “Analysis and improvements to Kabat and structurally correct numbering of antibody variable domains." Mol Immunol. 2008 Aug;45(14):3832-9. In some embodiments, the CDRs are defined using the Paratome tooldescribed by Kunik V, Peters B, and Ofran Y. (2012) “Structural consensus among antibodies defines the antigen binding site." PLoS Comput Biol. ;8(2):e1002388.

[0056] In some embodiments, these engineered dual binding antibodies may be used in a therapeutic method for treating a subject suffering from an allergic or respiratory condition. In other embodiments, the dual binding antibodies described here may be used for treating cancer.Engineered Trop2 / Nectin-4 Dual Binding Antibodies

[0057] With the assistance of artificial intelligence (Al) technology, a library for dual specific human Trop2 (hTrop2) and human Nectin4 (hNectin4) antibodies was designed. The antibody sequences of interest bind to both Trop2 and Nectin-4, allowing a broad number of tumor indications to be targeted.

[0058] As used herein, in some embodiments the term “dual binding antibodies” and the like, is interchangeable with the term “multibodies” and refers to antibodies with more than one binding specificity within a single Fv domain. As used herein, the terms “Fv domain” and “Fv region” may in some embodiments, be used interchangeably having all the same meanings and qualities.

[0059] The dual binding antibodies disclosed herein can bind within a single Fv domain, to human Trop2 and to human Nectin-4. In some embodiments, the dual antibodies bind Trop2 and Nectin-4 in a mutual exclusive manner. In some embodiments, a fragment antigen-binding (Fab) of an anti-human Trop2 and Nectin-4 antibody comprises the Fab region for human Trop2 and for human Nectin-4. In some embodiments, the paratope for human Trop2 and the paratope for Nectin-4 are comprised within the same Fab.

[0060] In some embodiments, a dual binding antibody is in the form of immune cell engagers, Antibody Drug Conjugate (ADC), Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC), Antibody-Dependent Cellular Phagocytosis (ADCP), Complement Dependent Cytotoxicity (CDC), radiolabeled antibody, cytokine conjugated antibodies, protein conjugated antibodies, peptide conjugated antibodies, nucleic acid conjugated antibodies, small molecule conjugated antibodies, antibody-based delivery, direct neutralization or any combination thereof. In some embodiments, a dual binding antibody or a dual binding fragment thereof is in the form of an ADC.

[0061] Antibody-drug conjugates (ADCs) are a class of targeted cancer therapies thatcombine the specificity of antibodies with the potency of cytotoxic drugs. The antibody component of an ADC is designed to recognize and bind to specific antigens expressed on the surface of cancer cells, allowing for selective targeting of the cytotoxic drug. Advantageously, an ADC should possess high specificity and affinity for the tumor antigen, stable binding of the cytotoxic payload to the antibody, and efficient internalization into the cancer cell. High internalization rate is beneficial as once the ADC binds to the target antigen; it is internalized by the cancer cell. Inside the cell, the conjugated cytotoxic drug is typically released, where it exerts its mechanism of action, disrupting cellular processes, leading to the cancer cell death from within. Typically, efficient internalization may minimize off-target effects and enhance therapeutic efficacy.

[0062] In some embodiments, a dual binding antibody disclosed herein demonstrates characteristics beneficial for an ADC, including but not limited to, superior internalization capabilities into cancer cells compared to mono-targeting antibody drug conjugates (See Example 2). In some embodiments, the dual binding antibody in an ADC modality can overcome limitations of traditional ADCs and offer improved efficacy and / or reduced toxicity due to its specificity and targeting capability. In some embodiments, the dual binding antibody in an ADC format exhibits improved precision and therapeutic efficacy in treating solid tumors.

[0063] A skilled artisan would appreciate that a component drug of an ADC may encompass any cytotoxic drug that causes a change in a subject’s physiology when administered to the subject. At the cellular level, a drug component of an ADC may encompass any chemical substance used to treat, cure, prevent, or diagnose a disease, disorder, or aberrant biological condition, for example, but not limited to treating a cancer.

[0064] In some embodiments, the dual binding antibodies disclosed herein have several advantages as demonstrated and detailed in the Examples. In some embodiments, the dual binding antibody are in the form of an ADC and are characterized as having high specificity and affinity for the tumor antigens, stable binding of the cytotoxic payload to the antibody, and efficient internalization into the cancer cell, thereby minimizing off-target effects and enhancing therapeutic efficacy.

[0065] In some embodiments, the dual binding antibody is associated with a moiety that binds another target.

[0066] In some embodiments, a dual binding antibody comprises an antibody comprisingtwo binding specificities within a single variable domain (Fv domain). In certain embodiments, a dual binding antibody disclosed herein binds to Trop2 and Nectin-4. In the case of Trop2 / Nectin-4 dual binding antibodies or a dual binding fragment thereof, the binding to Trop2 and to Nectin-4 within a single Fv binding domain is mutually exclusive (Fig. 1). In some embodiments, the multibody disclosed herein functions as an "OR" gate (Fig. 1) and is capable of binding either Trop2 or Nectin-4, wherein the binding to Trop2 and Nectin-4 is mutually exclusive. In some embodiments, the binding target of a dual binding antibody is modulated by time, location, and target concentration. In some embodiments, a dual binding IgG or F(ab’)2 fragment antibody, can bind Trop2 with both arms; Nectin-4 with both arms; or Trop2 on one arm and Nectin-4 in the second arm.

[0067] As used throughout, in some embodiments the term “Trop2 / Nectin-4 dual binding antibody” may be used interchangeably with the terms “dual binding antibody”, “dual binding fragment thereof’, and “dual binding antibody fragment thereof’, and the like, having all the same meanings and qualities.

[0068] In some embodiments, the present disclosure provides an isolated Trop2 / Nectin- 4 dual binding antibody comprising three complementarity determining regions (CDRs) on a heavy chain (HCDR1, HCDR2, and HCDR3) and three CDRs on a light chain (LCDR1 , LCDR2, and LCDR3) (see e.g., Tables 3A, 3B, 3C, 4A, 4B, and 4C). In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises HCDR1 , HCDR2, and HCDR3 within a variable heavy chain sequence and LCDR1, LCDR2, and LCDR3 within a variable light chain sequence. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises the HCDR1 , HCDR2, and HCDR3, and the LCDR1 , LCDR2, and LCDR3 sequences as provided in Tables 3A, 3B, or 3C and Tables 4A, 4B, or 4C, wherein selection of the HCDR and LCDR regions is from the same clone set.

[0069] In some embodiments, the amino acid sequences for the heavy and light chain CDRs are defined according to the Chothia numbering scheme. In other embodiments, the CDRs are defined according to the Kabat numbering scheme. In other embodiments, the CDRs are defined according to the IMGT® numbering scheme. In other embodiments, the CDRs are defined according to the AbM numbering scheme. In another embodiment, the CDRs are defined according to Paratome. In another embodiment, the CDRs are defined according to any numbering scheme known in the art.

[0070] In some embodiments, the CDRs are Chothia defined CDRs as set forth in Table3A (Heavy chain CDRs) and Table 4A (Light chain CDRs) (See Example 1). In some embodiments, the CDRs are IMGT® defined CDRs as set forth in Table 3B (Heavy chain CDRs) and Table 4B (Light chain CDRs) (See Example 1). In some embodiments, the CDRs are Kabat defined CDRs as set forth in Table 3C (Heavy chain CDRs) and Table 4C (Light chain CDRs) (See Example 1).

[0071] An isolated Trop2 / Nectin-4 dual binding antibody comprising three heavy chain complementarity determining regions (CDRs) (HCDR1 , HCDR2, and HCDR3) and three light chain CDRs (LCDR1, LCDR2, and LCDR3), wherein the amino acid sequences of HCDR1, HCDR2 and HCDR3 comprise the amino acid sequences set forth in Table 3A and wherein the amino acid sequence of LCDR1, LCDR2 and LCDR3 comprise the amino acid sequences set forth in Table 4A, and wherein the amino acid sequences for HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 are all selected from the same clone variant.

[0072] A skilled artisan would appreciate that theTrop2 / Nectin-4 dual binding antibodies or dual binding fragments thereof disclosed herein bind Trop2 and Nectin-4 within the same Fv region.

[0073] The skilled artisan would appreciate that the heavy and light CDR regions comprised within an isolated Trop2 / Nectin-4 dual binding antibody are selected based on pairing of a HCDR set (HCDR1 , HCDR2, and HCDR3) with a LCDR set (LCDR1 , LCDR2, and LCDR3) based on clone names, as provided in Tables 3A, 3B, 3C, 4A, 4B, and 4C (e.g., HCDR1 , HCDR2, and HCDR3 of CID1445 in Table 3A with LCDR1 , LCDR2, and LCDR3 of CID1445 in Table 4A).

[0074] In certain embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises three complementarity determining regions (CDRs) on a heavy chain (HCDR1 , HCDR2, and HCDR3) and three CDRs on a light chain (LCDR1 , LCDR2, and LCDR3), wherein the HCDR1, HCDR2 and HCDR3 comprise the amino acid sequences set forth in Table 3A (SEQ ID NOs: 197-294, 790, 791 ; SEQ ID NOs: 295-392, 792, 793; and SEQ ID NOs: 393-490, 794, 795, respectively), and wherein the LCDR1, LCDR2 and LCDR3 comprise the amino acid sequences set forth in Table 4A (SEQ ID NOs: 491-588, 796, 797; SEQ ID NOs: 589-686, 798, 799; and SEQ ID NOs: 687-784, 800, 801, respectively), and wherein the amino acid sequences for HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are selected from the same clone variant.

[0075] In some embodiments, the HCDR1 comprises the amino acid sequence of SEQID NO: 216, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 314, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 412, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 510, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 608, the LCDR3 comprises the amino acid sequence of SEQ ID NO: 706.

[0076] In other embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 283, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 381 , the HCDR3 comprises the amino acid sequence of SEQ ID NO: 479, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 577, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 675, the LCDR3 comprises the amino acid sequence of SEQ ID NO: 773.

[0077] Yet, in other embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 790, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 792, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 794, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 796, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 798, the LCDR3 comprises the amino acid sequence of SEQ ID NO: 800.

[0078] In other embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 791 , the HCDR2 comprises the amino acid sequence of SEQ ID NO: 793, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 795, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 797, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 799, the LCDR3 comprises the amino acid sequence of SEQ ID NO: 801.

[0079] In some embodiments of an isolated Tro p2 / N ectin-4 dual binding antibody or dual binding fragment thereof, the antibody or fragment thereof comprises three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 814, SEQ ID NO: 815, SEQ ID NO: 816, SEQ ID NO: 817, SAS,and SEQ ID NO: 819, respectively;(c) SEQ ID NO: 820, SEQ ID NO: 821 , SEQ ID NO: 822, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(d) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(e) SEQ ID NO: 823, SEQ ID NO: 824, SEQ ID NO: 825, SEQ ID NO: 826, SAS, and SEQ ID NO: 828, respectively;(f) SEQ ID NO: 829, SEQ ID NO: 830, SEQ ID NO: 831 , SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(g) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively;(h) SEQ ID NO: 832; SEQ ID NO: 833; SEQ ID NO: 834, SEQ ID NO: 835, SAS, and SEQ ID NO: 837, respectively; or(i) SEQ ID NO: 838; SEQ ID NO: 839; SEQ ID NO: 840, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.

[0080] In some embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 791, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 793, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 795, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 797, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 799, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 801. In some embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 814, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 815, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 816, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 817, the LCDR2 comprises the amino acid sequence of SAS, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 819. In some embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 820, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 821 , the HCDR3 comprises the amino acid sequence of SEQ ID NO: 822, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 797, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 799, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 801.

[0081] In some embodiments, the HCDR1 comprises the amino acid sequence of SEQID NO: 216, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 314, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 412, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 510, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 608, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 706. In some embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 823, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 824, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 825, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 826, the LCDR2 comprises the amino acid sequence of SAS, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 828. In some embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 829, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 830, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 831 , the LCDR1 comprises the amino acid sequence of SEQ ID NO: 510, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 608, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 706.

[0082] In some embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 790, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 792, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 794, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 796, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 798, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 800. In some embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 832, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 833, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 834, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 835, the LCDR2 comprises the amino acid sequence of SAS, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 837. In some embodiments, the HCDR1 comprises the amino acid sequence of SEQ ID NO: 838, the HCDR2 comprises the amino acid sequence of SEQ ID NO: 839, the HCDR3 comprises the amino acid sequence of SEQ ID NO: 840, the LCDR1 comprises the amino acid sequence of SEQ ID NO: 796, the LCDR2 comprises the amino acid sequence of SEQ ID NO: 798, and the LCDR3 comprises the amino acid sequence of SEQ ID NO: 800.

[0083] In some embodiments of an isolated Tro p2 / N ectin-4 dual binding antibody ordual binding fragment thereof, the antibody or fragment thereof comprises three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(c) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.

[0084] In some embodiments, HCDR1 , HCDR2, and HCDR3 are comprised within a heavy chain variable region (VH). In some embodiments, LCDR1 , LCDR2, and LCDR3 are comprised within a light chain variable region (VL). In some embodiments, a dual binding antibody comprises a VH and a VL having the amino acid sequences set forth in Tables 1 and 2. The skilled artisan would appreciate that the VH and VL regions comprised within an isolated Trop2 / Nectin-4 dual binding antibody are selected based on pairing of a VH sequence with a VL sequence based on clone names, as provided in Tables 1 and 2 (e.g., VH of CID1445 in Table 1 with VL of CID1445 in Table 2).

[0085] In some embodiments, an isolated T rop2 / Nectin-4 dual binding antibody or a dual binding fragment thereof comprises a heavy chain variable domain (VH) and a light chain variable domain (VL), said VH and VL comprising the HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 regions, respectively, wherein the amino acid sequences of the VH and VL regions comprise the amino acid sequences set forth in Table 1 (SEQ ID NOs: 1-98, 786, 787) and Table 2 (SEQ ID NOs: 99-196, 788, 789), and wherein the amino acid sequences for VH and VL are selected from the same clone variant.

[0086] In some embodiments, the VH comprises the amino acid sequence of SEQ ID NO: 20 and the VL comprises the amino acid sequence of SEQ ID NO: 118. In another embodiment, the VH comprises the amino acid sequence of SEQ ID NO: 87 and the VL comprises the amino acid sequence of SEQ ID NO: 185. In other embodiments, the VH comprises the amino acid sequence of SEQ ID NO: 786 and the VL comprises the amino acid sequence of SEQ ID NO:788. Yet, in other embodiments, the VH comprises theamino acid sequence of SEQ I D NO: 787 and the VL comprises the amino acid sequence of SEQ ID NO: 789.

[0087] In some embodiments, the isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprises a heavy chain variable domain (VH) and a light chain variable domain (VL), the VH and VL comprising the HCDR1 , HCDR2, and HCDR3 regions and the LCDR1 , LCDR2, and LCDR3 regions, respectively, wherein the amino acid sequences of the VH and VL comprise(a) SEQ ID NOs: 787 and 789, respectively;(b) SEQ ID NOs: 20 and 118, respectively; or(c) SEQ ID NOs: 786 and 788, respectively.

[0088] In some embodiments, the isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprises a heavy chain variable domain (VH) and a light chain variable domain (VL), the VH and VL comprising the HCDR1 , HCDR2, and HCDR3 regions and the LCDR1, LCDR2, and LCDR3 regions, respectively, wherein the amino acid sequences of the VH and VL comprise SEQ ID NOs: 787 and 789, respectively. In some embodiments, the isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprises a heavy chain variable domain (VH) and a light chain variable domain (VL), the VH and VL comprising the HCDR1 , HCDR2, and HCDR3 regions and the LCDR1 , LCDR2, and LCDR3 regions, respectively, wherein the amino acid sequences of the VH and VL comprise SEQ ID NOs: 20 and 118, respectively. In some embodiments, the isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprises a heavy chain variable domain (VH) and a light chain variable domain (VL), the VH and VL comprising the HCDR1 , HCDR2, and HCDR3 regions and the LCDR1 , LCDR2, and LCDR3 regions, respectively, wherein the amino acid sequences of the VH and VL comprise SEQ ID NOs: 786 and 788, respectively.

[0089] In some embodiments, a dual binding Trop2 / N ectin-4 antibodies or dual binding fragments thereof comprise VH and VL sequences that are at least 90% (e.g., at least 90%, 95%, 96%, 97%, 98%, or 99%) identical to the VH and VL sequences set forth above and as disclosed in Tables 1 and 2. One skilled in the art would appreciate that percent sequence identity may be determined using any of a number of publicly available software application, for example but not limited to BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters.

[0090] In some embodiments, a dual binding Trop2 / N ectin-4 antibodies or dual binding fragments thereof comprises a heavy chain variable region (VH) and a light chain variable region (VL), wherein the amino acid sequences for the heavy chain variable region and the light chain variable region are set forth in any of the VH / VL sets presented for the antibodies of Tables 1 and 2, or comprise homologous sequences that are at least 90% (e.g., at least 90%, 95%, 96%, 97%, 98%, or 99%) identical to the VH and VL sequences set forth in Tables 1 and 2.

[0091] A skilled artisan would appreciate that the term “homology” and grammatical forms thereof, encompasses the degree of similarity, e.g., identity between two or more structures. The terms “homologous sequences” or “homologs” of said sequences and the like, encompass regions in macromolecules that have a similar order of amino acids or nucleotides. Percent sequence identity is a number that describes how similar the query sequence is to the target sequence; with respect to amino acid sequences percent sequence identity indicates how many amino acid residues in each sequence are identical and with respect to nucleotide sequences identity indicates how many nucleic acids in each sequence are identical.

[0092] A skilled artisan would appreciate that a dual binding Trop2 / Nectin-4 antibody or a dual binding fragment thereof encompasses in its broadest sense an antibody that specifically binds an antigenic determinant of Trop2 and of Nectin-4 within a single Fv region. In some embodiments, homologs of a dual binding Trop2 / Nectin-4 antibody or a dual binding fragment thereof bind Trop2 and of Nectin-4 within a single Fv region.

[0093] In certain embodiments, disclosed herein is an isolated Trop2 / Nectin-4 dual binding antibody or a dual binding fragment thereof, comprising a heavy chain variable domain (VH) and a light chain variable domain (VL) wherein the amino acid sequences of the VH and VL comprise(a) SEQ ID NOs: 787 and 789, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 787 and 789, respectively;(b) SEQ ID NOs: 20 and 118, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 20 and 118, respectively; or(c) SEQ ID NOs: 786 and 788, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 786 and 788, respectively; and wherein the dual binding antibody or the dual binding fragment thereof binds Trop2 andNectin-4 within the same Fv region.

[0094] In certain embodiments of an isolated Trop2 / N ectin-4 dual binding antibody or a dual binding fragment thereof comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), the VH and VL comprise SEQ ID NOs: 787 and 789, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 787 and 789, respectively; wherein the dual binding antibody or the dual binding fragment thereof binds Trop2 and Nectin-4 within the same Fv region. In some embodiments of an isolated Trop2 / Nectin-4 dual binding antibody or a dual binding fragment thereof comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), the VH and VL comprise SEQ ID NOs: 20 and 118, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 20 and 118, respectively; wherein the dual binding antibody or the dual binding fragment thereof binds Trop2 and Nectin-4 within the same Fv region. In certain embodiments of an isolated Trop2 / Nectin-4 dual binding antibody or a dual binding fragment thereof comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), the VH and VL comprise SEQ ID NOs: 786 and 788, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 786 and 788, respectively; wherein the dual binding antibody or the dual binding fragment thereof binds Trop2 and Nectin-4 within the same Fv region.

[0095] As used herein, the terms “heavy chain variable region” may be used interchangeable with the term “VH domain”, “VH region”, or “VH”, having all the same meanings and qualities. As used herein, the term “light chain variable region” may be used interchangeable with the term “VL domain”, “VL region”, or “VL”, having all the same meanings and qualities.

[0096] A skilled artisan would appreciate that a Trop2 / Nectin-4 dual binding antibody encompasses in its broadest sense an antibody that specifically binds an antigenic determinant of Trop2 and Nectin-4 with the same Fv region. The skilled artisan would appreciate that specificity for binding to Trop2 or Nectin-4 or both reflects that the binding is selective for the antigen(s) and can be discriminated from unwanted or nonspecific interactions. In certain embodiments, a Trop2 / Nectin-4 dual binding antibody comprises an antibody binding fragment.

[0097] In some embodiments, an antigenic determinant comprises a Trop2 or Nectin-4epitope. In certain embodiments, the term "epitope" includes a polypeptide determinant, capable of specific binding to an anti-Trop2 or anti-Nectin-4 binding domain. An epitope is a region of an antigen that is bound by an antibody or an antigen-binding fragment thereof. In some embodiments, the antigen-binding fragment of an antibody comprises a heavy chain variable region, a light chain variable region, or a combination thereof as described herein.

[0098] In certain embodiments, epitope determinants include chemically active surface groupings of molecules such as amino acids, sugar side chains, phosphoryl or sulfonyl, and may in certain embodiments have specific three-dimensional structural characteristics, and / or specific charge characteristics. In certain embodiments, the dual binding antibody is said to specifically bind an T rop2 or Nectin-4 epitope when it preferentially recognizes T rop2 or Nectin-4 in a complex mixture of proteins and / or macromolecules.

[0099] In some embodiments, a dual binding antibody is said to specifically bind an epitope when the equilibrium dissociation constant is < 10'5, 10'6, or 10'7M. In some embodiments, the equilibrium dissociation constant may be < 10'8M or 10'9M. In some further embodiments, the equilibrium dissociation constant may be < 10'10M, 10'11M, or 10'12M. In some embodiments, the equilibrium dissociation constant may be in the range of < 10’5M to 10'12M.[000100] An antibody binding domain can be a fragment of an antibody or a genetically engineered product of one or more fragments of the antibody, which fragment is involved in specifically binding with the antigen. By "specifically binding" is meant that the binding is selective for the antigen of interest, for example for Trop2 or Nectin-4 in embodiments described herein and can be discriminated from unwanted or nonspecific interactions. As used herein, the term “dual binding antibody” may in certain embodiments, encompass complete immunoglobulin structures, fragments thereof, or domains thereof.[000101] Examples of antibody binding domains include, without limitation, a complementarity determining region (CDR), a variable region (Fv), a VH domain, a light chain variable region (VL), a heavy chain, a light chain, a single chain variable region (scFv), and a Fab fragment. A skilled artisan would appreciate that an scFv is not actually a fragment of an antibody, but instead is a fusion polypeptide comprising the variable heavy chain (VH) and variable light chain (VL) regions of an immunoglobulin, connected by a short linker peptide of for example but not limited to ten to about 25 amino acids. The skilled artisan would also appreciate that the term “Fab” with regard to an antibody, generallyencompasses that portion of the antibody consisting of a single light chain (both variable and constant regions) bound to the variable region and first constant region of a single heavy chain by a disulfide bond.[000102] In some embodiments of an isolated Trop2 / Nectin-4 dual binding fragment formatted as an scFv, the scFv comprises a VH-linker-VL. In some embodiments of an isolated Trop2 / Nectin-4 dual binding fragment formatted as an scFv, the scFv comprises a VL-linker-VH. In some embodiments, the linker comprises a G4Slinker. In some embodiments the linker comprises a (G4S)s linker.[000103] In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof in the form of an scFv dual binding fragment thereof, comprises the amino acid sequence SEQ ID NO: 811; SEQ ID NO: 812; or SEQ ID NO: 813.[000104] In some embodiments, an antibody encompasses whole antibody molecules, including monoclonal, polyclonal and multispecific (e.g., bispecific, trispecific, etc.,) antibodies. In some embodiments, a Trop2 / Nectin-4 dual binding antibody or binding fragment thereof may be comprised within a multi-specific antibody able to bind additional antigens. Non-limiting examples of multi-specific antibodies include T cell and NK cell engagers, e.g., multi-specific T cell Engager (such as in the format of a BiTE®) formatted antibodies. In some embodiments, an dual binding antibody comprises an antibody fragment or fragments that retain binding specificity including, but not limited to, variable heavy chain (VH) fragments, variable light chain (VL) fragments, Fab fragments, F(ab')2 fragments, scFv fragments, Fv fragments, minibodies, diabodies, triabodies, and tetrabodies (see, e.g., Hudson and Souriau, Nature Med. 9: 129-134 (2003) (hereby incorporated by reference in their entirety)). Also encompassed are humanized, primatized, and chimeric antibodies.[000105] As used herein, in some embodiments, the term “Antibody” may be used interchangeably with the terms “dual binding antibody”, “Trop2 / Nectin-4 dual binding antibody”, “dual binding antibody binding fragment”, “antibody binding fragment”, “Ab”, and “Immunoglobulin” having all the same qualities and meanings. Similarly, as used herein, in some embodiments, the term “Antibody or fragments thereof’ may be used interchangeably with the term “Immunoglobulin or fragments thereof’ having all the same qualities and meanings. Thus, a skilled artisan would appreciate that in some embodiments, “an antibody or fragments thereof’, or “immunoglobulins or fragments thereof’ may encompass IgGimmunoglobulins or binding fragments thereof or structures comprising a binding fragment or fragments thereof, including but not limited to an IgG, an scFv fragment, an Fab fragment, an F(ab')2 fragment, Fv fragments, minibodies, diabodies, triabodies, and tetrabodies. A skilled artisan would appreciate that a dual binding antibody fragment, i.e. , a “dual binding fragment thereof’ maintains the ability to bind T rop2 and Nectin-4 within a single Fv.[000106] In some embodiments, the term "antibody" refers to intact molecules as well as functional fragments thereof, such as Fab, F(ab')2, and Fv that are capable of specifically interacting with a desired target as described herein, for example, binding to cancer cells. In some embodiments, the antibody fragments comprise:(1) Fab, the fragment which contains a monovalent antigen-binding fragment of an antibody molecule, which can be produced by digestion of whole antibody with the enzyme papain to yield an intact light chain and a portion of one heavy chain;(2) Fab', the fragment of an antibody molecule that can be obtained by treating whole antibody with pepsin, followed by reduction, to yield an intact light chain and a portion of the heavy chain; two Fab' fragments are obtained per antibody molecule;(3) (Fab')2, the fragment of the antibody that can be obtained by treating whole antibody with the enzyme pepsin without subsequent reduction; F(ab')2 is a dimer of two Fab' fragments held together by two disulfide bonds;(4) Fv, a genetically engineered fragment containing the variable region of the light chain and the variable region of the heavy chain expressed as two chains; and(5) Single chain antibody ("SCA"), a genetically engineered molecule containing the variable region of the light chain and the variable region of the heavy chain, linked by a suitable polypeptide linker as a genetically fused single chain molecule.[000107] A skilled artisan would appreciate that the term “monovalent’ may encompass the number of antigen binding sites. For example, but not limited to a Fab or Fv format, wherein the Trop2 / N ectin-4 dual binding antibody would be monovalent.[000108] In some embodiments, an isolated Trop2 / N ectin-4 dual binding antibody is monovalent and has two specificities. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody is bivalent and has two specificities. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody has at least two specificities.[000109] Methods of making these fragments are known in the art (see for example, Harlow and Lane, Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, New York,1988, incorporated herein by reference). In some embodiments, the isolated Trop2 / Nectin- 4 dual binding antibody or dual binding fragment thereof is in the form of an IgG, an Fv, an scFv, an Fab, a F(ab')2, a minibody, a diabody, a triabody, an immune-cell engager, a multispecific antibody, or a multi-engager; wherein optionally said IgG comprises an IgG 1 , lgG2, I gG3, or lgG4.[000110] As used herein “a bispecific antibody” is an antibody that has two distinct Fv binding domains, each composed of different monovalent antibody domain and each having one specificity, allowing it to bind separately to two different antigens. In some embodiments, a bispecific antibody may have two distinct Fv binding domains, each domain having one specificity, e.g., one arm binds Trop2 and the other arm binds Nectin-4. These binding domains can be configured using various formats, such as IgG, Fab, scFv, or VHH, etc.[000111] As used herein “a multi-specific antibody” is an antibody that consists of at least two distinct binding domains, wherein one binding arm comprises the dual binding antibody, and the other(s) binding arm is capable of binding at least one or more different target. In some embodiments, a multi-specific antibody comprises the dual-binding antibody in one domain fused to a different antibody in the second domain. In some embodiments, a multispecific antibody comprises more than two distinct binding domains, and each domain can bind more than one target, allowing the antibody to bind to more than two different targets. These binding domains can be configured using various antibody formats, such as Fab, scFv, VHH, IgG, etc.[000112] In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprises a multi-specific antibody. In some embodiments, the dual binding antibody is in a format of a symmetrical IgG.[000113] As used herein “an immune cell engager” refers to a bispecific or to a multi-specific antibody that comprises at least one Fv domain capable of binding an immune cell and at least another one Fv domain capable of binding to at least two different antigens expressed on target cells. In some embodiments, the immune cell engager facilitates target cell killing, although certain types, such as dendritic cell engagers, do not directly lead to target cell killing. Immune cell engagers can bind multiple immune cells and can target more than one antigen on the same target cell or on different target cells. Examples of immune cell engagers include, but are not limited to, those that bind T cells, NK cells, macrophages, dendritic cells, B cells, neutrophils, eosinophils, or basophils, etc.[000114] In some embodiments, a dual binding antibody disclosed herein comprises an immune cell engager having at least three binding specificities.[000115] In some embodiments, an immune cell engager comprises engineered antibodies comprising at least one Fv binding domain capable of binding a tumor-associated antigen and at least one Fv binding domain directed against an activating receptor in immune effector cells. In some embodiments, an immune cell engager comprises engineered antibodies comprising at least one Fv binding domain capable of binding one of two (two different) tumor-associated antigen and at least one Fv binding domain directed against an activating receptor in immune effector cells. In some embodiments, the tumor-associated antigen is Trop2. In some embodiments, the tumor-associated antigen is Nectin-4. In some embodiments, the two different tumor-associated antigens are Trop2 and Nectin-4.[000116] In some embodiments, a dual binding antibody disclosed herein is in the form of a multi-engager. In some embodiments, a dual binding antibody disclosed herein is in the form of a super engager.[000117] As used throughout the terms “arm” or “binding arm” may in some embodiments be interchangeable with the terms “Fv domain” or “Fv binding domain”, having all the same qualities and meanings.[000118] As used herein, a “T cell engager” refers to(a) a bispecific antibody that binds a single target expressed over T-cells with a single Fv domain and a second single target expressed over tumor cells with a second single Fv domain; or(b) a multi-specific antibody that binds more than one target and comprises one or more Fv domain(s) capable of binding one or more target(s) expressed on a T cell, and another Fv domain capable of binding to target cells. Typically, T cell engagers facilitate target cell killing. T cell engagers can also bind to other immune cells and may target more than one antigen on the same target cell or on different target cells.[000119] In some embodiment, a dual antibody disclosed herein is in the form of a T-cell engager having at least three specificities. In some embodiments, a Trop2 / Nectin-4 dual binding antibody is in the form of T-cell engager having three specificities. In some embodiments, a Trop2 / Nectin-4 dual binding antibody disclosed herein is an immune cell engager, for example but not limited to a T-cell engager.[000120] As used herein a “multi-engager” or “multi-cell engager” is an immune cell engager that can bind with one domain, one target expressed on an immune cell subtype within a single Fv domain, and another binding domain that can bind more than one target expressed on targeted cells within a single Fv domain. Multi-engagers are typically designed to target and deplete various types of cells. In some embodiments, a Trop2 / Nectin-4 dual binding antibody is a multi-engager. In some embodiments, a multi-engager has three specificities and comprises a dual binding antibody and a T cell immune engager targeting CD3 expressed on T cells.[000121] As used herein, a “super-engager” is an immune cell engager that can bind with one or more binding domain (Fv) more than one antigen target expressed on different immune cell subtypes, and another binding domain (Fv) that can bind more than one antigen target expressed on targeted cells within a single Fv domain. In one embodiment, a “superengager” is an immune cell engager that can bind with one binding domain (Fv) more than one antigen target expressed on different immune cell subtypes, and another binding domain (Fv) that can bind more than one antigen target expressed on targeted cells within a single Fv domain. In some cases, a super-engager facilitates target cell killing, although certain types, such as dendritic cell engagers, do not directly lead to target cell killing. Super engagers can bind multiple immune cell subtypes and can target more than one antigen on the same target cell or on different target cells. Examples of immune cell subtypes include, but are not limited to, T cells, NK cells, macrophages, dendritic cells, B cells, neutrophils, eosinophils, or basophils, etc. In some embodiments, a super-engager comprises at least four specificities and comprises a Trop2 / Nectin-4 dual antibody as disclosed herein and an immune cell engager having two binding specificities within a single Fv binding domain. In some embodiments, a Trop2 / Nectin-4 dual binding antibody is a super-engager.[000122] In some embodiments, described here are IgG-like T-cell engagers in a Duobody® format. Duobody® is described in: Labrijn, A. F. et al. Efficient generation of stable bispecific lgG1 by controlled Fab-arm exchange. Proc. Natl. Acad. Sci. II. S. A. 110, 5145-5150 (2013). In some embodiments, the dual binding antibody are formatted as a multi-specific antibody using the Duobody® technology. In such an embodiment, the dual binding antibody consists of two Fv domains, where one Fv domain comprises the variable domain, for example of a published anti-CD3 antibody derived from an approved T-cell engager (pacanalotamab), and the second Fv domain comprises the variable domain of a Tumor-Associated Antigen (TAA). In some embodiments, a multi-specific antibody is formatted using Genmab technology (Genmab, USA; Method of Duabody® production).[000123] In some embodiments, a Duobody® T-cell engager, is an IgG-like T-cell engager, comprising the Fv domain of the Trop2 / Nectin-4 dual binding antibody and the Fv domain of an anti-CD3 antibody.[000124] In some embodiments, the antibody fragments may be prepared by proteolytic hydrolysis of the antibody or by expression in E. coli or mammalian cells (e.g., Chinese hamster ovary cell culture or other protein expression systems) of DNA encoding the fragment.[000125] Antibody fragments can, in some embodiments, be obtained by pepsin or papain digestion of whole antibodies by conventional methods. For example, antibody fragments can be produced by enzymatic cleavage of antibodies with pepsin to provide a 5S fragment denoted F(ab')2. This fragment can be further cleaved using a thiol reducing agent, and optionally a blocking group for the sulfhydryl groups resulting from cleavage of disulfide linkages, to produce 3.5S Fab' monovalent fragments. Alternatively, an enzymatic cleavage using pepsin produces two monovalent Fab' fragments and an Fc fragment directly. These methods are described, for example, by Goldenberg, U.S. Pat. Nos. 4,036,945 and 4,331,647, and references contained therein, which patents are hereby incorporated by reference in their entirety. See Porter, R. R., Biochem. J., 73: 119-126, 1959. Other methods of cleaving antibodies, such as separation of heavy chains to form monovalent light-heavy chain fragments, further cleavage of fragments, or other enzymatic, chemical, or genetic techniques may also be used, so long as the fragments bind to the antigen that is recognized by the intact antibody.[000126] Fv fragments comprise an association of VH and VL chains. This association may be noncovalent, as described in Inbar et al., Proc. Nat. Acad. Sci. USA 69:2659-62, 1972. Alternatively, the variable chains can be linked by an intermolecular disulfide bond or crosslinked by chemicals such as glutaraldehyde. Preferably, the Fv fragments comprise VH and VL chains connected by a peptide linker. These single-chain antigen binding proteins (scFv) are prepared by constructing a structural gene comprising DNA sequences encoding the VH and VL domains connected by an oligonucleotide. The structural gene is inserted into an expression vector, which is subsequently introduced into a host cell such as E. coli. The recombinant host cells synthesize a single polypeptide chain with a linker peptide bridgingthe two V domains. Methods for producing scFv are described, for example, by Whitlow and Filpula, Methods, 2: 97-105, 1991 ; Bird et al., Science 242:423-426, 1988; Pack et al., Bio / Technology 11 :1271-77, 1993; and Ladner et al., U.S. Pat. No. 4,946,778, which is hereby incorporated by reference in its entirety.[000127] Another form of an antibody fragment is a peptide coding for a single complementarity-determining region (CDR). CDR peptides ("minimal recognition units") can be obtained by constructing genes encoding the CDR of an antibody of interest. Such genes are prepared, for example, by using the polymerase chain reaction to synthesize the variable region from RNA of antibody-producing cells. See, for example, Larrick and Fry, Methods, 2: 106-10, 1991.[000128] In some embodiments, the antibodies or fragments as described herein may comprise “humanized forms” of antibodies. In some embodiments, the term “humanized forms of antibodies” refers to non-human (e.g., murine) antibodies, which are chimeric molecules of immunoglobulins, immunoglobulin chains or fragments thereof (such as Fv, Fab, Fab', F(ab')2 or other antigen-binding subsequences of antibodies) which contain minimal sequence derived from non-human immunoglobulin. Humanized antibodies include human immunoglobulins (recipient antibody) in which residues form a complementary determining region (CDR) of the recipient are replaced by residues from a CDR of a non- human species (donor antibody) such as mouse, rat or rabbit having the desired specificity, affinity and capacity. In some instances, Fv framework residues of the human immunoglobulin are replaced by corresponding non-human residues. Humanized antibodies may also comprise residues which are found neither in the recipient antibody nor in the imported CDR or framework sequences. 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 CDR regions correspond to those of a non-human immunoglobulin and all or substantially all of the FR regions are those of a human immunoglobulin consensus sequence. The humanized antibody optimally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin [Jones et al., Nature, 321 :522-525 (1986); Riechmann et al., Nature, 332:323-329 (1988); and Presta, Curr. Op. Struct. Biol., 2:593-596 (1992)].[000129] Methods for humanizing non-human antibodies are well known in the art. Generally, a humanized antibody has one or more amino acid residues introduced into itfrom a source which is non-human. These non-human amino acid residues are often referred to as import residues, which are typically taken from an import variable domain. Humanization can be essentially performed following the method of Winter and co-workers [Jones et al., Nature, 321 :522-525 (1986); Riechmann et al., Nature 332:323-327 (1988); Verhoeyen et al., Science, 239:1534-1536 (1988)], by substituting rodent CDRs or CDR sequences for the corresponding sequences of a human antibody. Accordingly, such humanized antibodies are chimeric antibodies (U.S. Pat. No. 4,816,567), wherein substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non-human species. In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies.[000130] Human antibodies can also be produced using various techniques known in the art, including phage display libraries [Hoogenboom and Winter, J. Mol. Biol., 227:381 (1991); Marks et al., J. Mol. Biol., 222:581 (1991)]. The techniques of Cole et al. and Boerner et al. are also available for the preparation of human monoclonal antibodies (Cole et al., Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, p. 77 (1985) and Boerner et al., J. Immunol., 147(1):86-95 (1991)]. Similarly, human antibodies can be made by introducing of human immunoglobulin loci into transgenic animals, e.g., mice in which the endogenous immunoglobulin genes have been partially or completely inactivated. Upon challenge, human antibody production is observed, which closely resembles that seen in humans in all respects, including gene rearrangement, assembly, and antibody repertoire. This approach is described, for example, in U.S. Pat. Nos. 5,545,807; 5,545,806; 5,569,825; 5,625,126; 5,633,425; 5,661 ,016, and in the following scientific publications: Marks et al., Bio / Technology 10, 779-783 (1992); Lonberg et al., Nature 368 856-859 (1994); Morrison, Nature 368 812-13 (1994); Fishwild et al., Nature Biotechnology 14, 845-51 (1996); Neuberger, Nature Biotechnology 14, 826 (1996); Lonberg and Huszar, Intern. Rev. Immunol. 1365-93 (1995).[000131] A skilled artisan would recognize that a “Heavy chain variable region” or “VH” of an antibody encompasses the fragment of the heavy chain that contains three CDRs interposed between flanking stretches known as framework (FR) regions, which are more highly conserved than the CDRs, and form a scaffold to support the CDRs. In certain embodiments, the terms a “Heavy chain variable region” or a “VH” may be usedinterchangeably with “VH domain”.[000132] A skilled artisan would recognize that a “Light chain variable region” or “VL” with regard to an antibody encompasses the fragment of the light chain that contains three CDRs interposed between framework (FR) regions. In certain embodiments, the terms a “Light chain variable region” or a “VL” may be used interchangeably with “VL domain”.[000133] In certain embodiments, the dual binding antibody comprising a VH domain comprising HCDRs, as described herein, may be encoded by a nucleic acid construct. In certain embodiments, the dual binding antibody comprising a VL domain comprising LCDRs, as described herein, may be encoded by a nucleic acid construct. In certain embodiments, the dual binding antibody comprising a VH domain comprising HCDRs and a VL domain comprising LCDRs, as described herein, may be encoded by a nucleic acid construct.[000134] In certain embodiments, the dual binding antibody comprising a VH domain comprising HCDRs, may be produced by expressing a nucleic acid construct comprising a nucleic acid sequence encoding the HCDRs from a host cell and isolating the antibody. In certain embodiments, the dual binding antibody comprising a VL domain comprising LCDRs, may be produced by expressing a nucleic acid construct comprising a nucleic acid sequence encoding the LCDRs from a host cell and isolating the antibody. In certain embodiments, the dual binding antibody comprising a VH domain comprising HCDRs and a VL domain comprising HCDRs, as described herein, may be produced by expressing a nucleic acid construct comprising a nucleic acid sequence encoding the HCDRs and LCDRs from a host cell and isolating the antibody. In some embodiments, the nucleic acid sequence encodes a VH region and a VL region. In some embodiments, the nucleic acid encodes the VH and VL regions set forth in Tables 1 and 2, respectively.[000135] In certain embodiments, dual antibody binding regions, as described herein include a heavy chain and a light chain CDR set, respectively, interposed between a heavy chain and a light chain framework region (FR) set which provide support to the CDRs and define the spatial relationship of the CDRs relative to each other. As used herein, the term “CDR set’ refers to the three hypervariable regions of a heavy or light chain variable region. Proceeding from the N-terminus of a heavy or light chain polypeptide, these regions are denoted as “CDR1”, “CDR2”, and “CDR3”, respectively. An antigen binding site, therefore, includes six CDRs, comprising the CDR set from each of a heavy and a light chain variableregion. Crystallographic analysis of a number of antigen-antibody complexes has demonstrated that the amino acid residues of CDRs form extensive contact with a bound antigen, wherein the most extensive antigen contact is with the heavy chain CDR3. Thus, the CDR regions are primarily responsible for the specificity of an antigen binding site.[000136] As used herein, the term “FR set” refers to the four flanking amino acid sequences which frame the CDRs of a CDR set of a heavy or light chain variable region. Some FR residues may contact bound antigen; however, FRs are primarily responsible for folding the variable region into the antigen-binding site, particularly the FR residues directly adjacent to the CDRs. Within FRs, certain amino residues and certain structural features are very highly conserved. In this regard, all variable region sequences contain an internal disulfide loop of around 90 amino acid residues. When the variable regions fold into a binding-site, the CDRs are displayed as projecting loop motifs which form an antigen-binding surface. It is generally recognized that there are conserved structural regions of FRs, which influence the folded shape of the CDR loops into certain “canonical” structures — regardless of the precise CDR amino acid sequence. Further, certain FR residues are known to participate in non-covalent interdomain contacts which stabilize the interaction of the antibody heavy and light chains.[000137] In certain embodiments, the dual binding antibody comprising a VH domain comprising HCDRs may be administered in a method of treating a subject in need, wherein said subject suffers from a disease or condition, for example but not limited to a solid cancer, a hematopoietic malignancy, a cancer metastasis, an unresectable cancer, or any combination thereof. In some embodiments, the dual binding antibody comprising a VH domain comprising HCDRs may be administered in a method of treating a subject in need, wherein said subject suffers from a disease or condition comprising hematopoietic malignancies. In some embodiments, the dual binding antibody comprising a VH domain comprising HCDRs may be administered in a method of treating a subject in need, wherein said subject suffers from a disease or condition, comprising metastatic cancer. In some embodiments, the dual binding antibody comprising a VH domain comprising HCDRs may be administered in a method of treating a subject in need, wherein said subject suffers from a disease or condition comprising unresectable cancer. In certain embodiments, the dual binding antibody comprising a VL domain comprising LCDRs may be administered in a method of treating a subject in need, wherein said subject suffers from a disease or condition comprising for example but not limited to a solid cancer, a hematopoietic malignancy, acancer metastasis, or any combination thereof. In certain embodiments, the dual binding antibody comprising a VH domain comprising HCDRs and a VL domain comprising LCDRs, may be administered in a method of treating a subject in need, wherein said subject suffers from a disease or condition comprising for example but not limited to a solid cancer, a hematopoietic malignancy, a cancer metastasis, or any combination thereof.[000138] In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises an IgG, an Fv, an scFv, an Fab, a F(ab')2, a minibody, a diabody, a triabody, an immune-cell engager, a multi-specific antibody, a super-engager, a multi-engager, or a combination thereof. In some embodiments, an isolated Trop2 / N ectin-4 dual binding antibody comprises an IgG, an Fv, an scFv, an Fab, an F(ab')2, a minibody, a diabody, a triabody, a DuoBody®, a multi-specific immune cell engager, a multi-engager or a single domain antibody. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody is monovalent, bivalent, or multivalent. Valency refers to the number of antigen binding sites on the antibody. Non-limiting examples of antibodies and binding fragments thereof having different valences include a scFv, which is monovalent, an lgG1 , which is bivalent, and a triabody, which is trivalent (multivalent).[000139] In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody is multispecific. Multi-specific refers to the number of epitopes bound, i.e. , multi- may encompass binding to more than one antigen epitope. Thus, a bispecific antibody specifically recognizes and binds 2 epitopes, which may comprise binding two different antigens or comprise binding 2 different epitopes on the same antigen, wherein each binding site for each epitope is within a different Fv domain. Similarly, a multi-specific antibody specifically recognizes multiple epitopes. A dual binding antibody disclosed herein may be part of a multi-specific antibody construct, wherein the construct would at least bind a Trop2 epitope and a Nectin- 4 epitope in a mutual exclusive manner, wherein both binding sites are within the same Fv region. For example, but not limited to, when a Trop2 / Nectin-4 dual binding antibody is part of an immune cell engager that may additionally be targeted to a T cell and / or a NK cell, the antibody entity comprises a multi-specific antibody.[000140] A skilled artisan would recognize that a variable region (“Fv”) with regard to an antibody encompasses the smallest fragment of the antibody to bear the complete antigen binding site. An Fv fragment consists of the variable region of a single light chain (VL) bound to the variable region of a single heavy chain (VH). As used throughout, in someembodiments, the terms “Fv region” and “Fv domain” may be used interchangeably having all the same meanings and qualities.[000141] A skilled artisan would recognize that a “single-chain Fv antibody” or “scFv” with regard to an antibody encompasses an engineered antibody consisting of a VL domain and a VH domain connected to one another directly or via a peptide linker sequence. The skilled artisan would appreciate that a linker, in some embodiments, may comprise a linear amino acid sequence.[000142] In some embodiments, peptide linker sequences contain, for example, Gly, Asn, and or Ser residues, in various combinations. Other near neutral amino acids, such as Thr and Ala, may also be included in the linker sequence.[000143] Other amino acid sequences which may be usefully employed as linkers include those disclosed in Maratea et al., Gene 40:39 46 (1985); Murphy et al., Proc. Natl. Acad. Sci. USA 83:8258 8262 (1986); U.S. Pat. No. 4,935,233 and U.S. Pat. No. 4,751 ,180; Chaudhary et al., 1990, Proc. Natl. Acad. Sci. U.S.A. 87:1066-1070; Bird et al., 1988, Science 242:423-426, incorporated herein in their entirety.[000144] In some embodiments, coding sequences of VH and VL domains of the dual binding antibody or fragment thereof can be fused directly.[000145] A peptide linker, in certain embodiments, is designed to enable the correct interaction between two beta-sheets forming the variable region of the single chain antibody. Any suitable linkers can be used to make an indirect link, such as without limitation, peptide linker, polymer linker, and chemical linker. In certain embodiments, the covalent link is an indirect link through a peptide linker.[000146] In some embodiments, an antibody comprises a mutated immunoglobulin. In some embodiments, a mutated immunoglobulin is unable to bind to a fragment crystallizable gamma receptor (FcyR). In some embodiments, the isolated Trop2 / N ectin-4 dual binding antibody or dual binding fragment thereof is unable to bind to fragment crystallizable gamma receptors (FcyRs).ln some embodiments, the mutation is located in the fragment crystallizable (Fc) region of the heavy chain (HC). In some embodiments, a mutated immunoglobulin is unable to bind to a fragment crystallizable gamma receptor (FcyR). In some embodiments, the isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof is unable to bind to fragment crystallizable gamma receptors (FcyRs). In some embodiments, a mutated immunoglobulin has reduced binding to a fragmentcrystallizable gamma receptor (FcyR). In some embodiments, the isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof has reduced binding to fragment crystallizable gamma receptors (FcyRs).ln some embodiments, a mutated immunoglobulin is unable to bind or has reduced binding to a fragment crystallizable gamma receptor (FcyR). In some embodiments, the isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof is unable to bind or has reduced binding to fragment crystallizable gamma receptors (FcyRs). In some embodiments, the isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof is unable to bind or has reduced binding to fragment crystallizable gamma receptors (FcyRs), wherein the reduced binding is compared with the Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof lacking a mutation in the Fc region of the heavy chain.[000147] Some embodiments of mutated immunoglobulins comprising mutations in the HC include but are not limited to an IgG that does not bind antibody-dependent cellular cytotoxicity (ADCC) components. IgG comprising L234A / L235A (LALA) mutations or L234A / L235A / P329G (LALAPG) mutations cannot bind the Fey receptors (See, Xu D, Alegre ML, Varga SS, Rothermel AL, Collins AM, Pulito VL, et al. In vitro characterization of five humanized OKT3 effector function variant antibodies. Cell Immunol. (2000) 200:16-26. 10.1006 / cimm.2000.1617). In some embodiments, an antibody comprises a mutated immunoglobin, wherein the heavy chain (HC) comprises a mutation, said mutation comprising either an LALA or LALAPG mutation or any other single or multiple amino acid mutations known in the art that reduce or abrogate antibody binding to Fey receptors. In some embodiments, the dual antibody comprises an IgG comprising the L234A / L235A (LALA) mutations. In some embodiments, the dual antibody comprises an IgG comprising the L234A / L235A / P329G (LALAPG) mutations. The isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the antibody comprises a mutation in the heavy chain (HC), the mutation comprising a L234A L235A (LALA) mutation or a L234A L235A P329G (LALAPG) mutation.[000148] The mutations as numbered here are based on an EU numbering convention used for the constant region (See, Xu D, Alegre ML, Varga SS, Rothermel AL, Collins AM, Pulito VL, et al. In vitro characterization of five humanized OKT3 effector function variant antibodies. Cell Immunol. (2000) 200:16-26. 10.1006 / cimm.2000.1617).[000149] In some embodiments, a mutated IgG comprises an lgG1, wherein the Fc regionis engineered. In some embodiments, a mutated IgG comprises an lgG2, wherein the Fc region is engineered. In some embodiments, a mutated IgG comprises an lgG3, wherein the Fc region is engineered. In some embodiments, a mutated IgG comprises an lgG4, wherein the Fc region is engineered. In certain embodiments, mutations within an Fc region of an antibody abolishes immune effector functions of the antibody. In some embodiments, an isolated dual binding antibody comprises a Fc-mutated IgG, wherein said mutant IgG is unable to bind or has reduced binding to antibody-dependent cellular cytotoxicity components. In some embodiments, an isolated dual binding antibody comprises a Fc- mutated IgG, wherein said mutant IgG is unable to bind to antibody-dependent cellular cytotoxicity components. In some embodiments, an isolated dual binding antibody comprises a Fc-mutated IgG, wherein said mutant IgG has reduced binding to antibodydependent cellular cytotoxicity components.[000150] In some embodiments, a Trop2 / Nectin-4 dual binding antibody comprises a heavy chain comprising a mutation that reduces binding to Fey receptor(s). In some embodiments, a Trop2 / Nectin-4 dual binding antibody is unable to bind to antibody-dependent cellular cytotoxicity components. In some embodiments, a Trop2 / Nectin-4 dual binding antibody is unable to bind or has reduced binding to antibody-dependent cellular cytotoxicity components. In certain embodiments, a Trop2 / Nectin-4 dual binding antibody comprises a L234A L235A (LALA) mutation or a L234A L235A P329G (U\U\PG) mutation. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprises a mutation in the heavy chain (HC), the mutation comprising a L234A L235A (LALA) mutation or a L234A L235A P329G (LALAPG) mutation.[000151] In some aspects, an isolated Trop2 / Nectin-4 dual binding antibody or a dual binding fragment thereof cannot trigger antibody-mediated effector functions, including antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cellular toxicity (CDC).[000152] In some embodiments, a dual binding antibody or a dual binding fragment thereof comprises a native Fc format.[000153] In some embodiments, an isolated dual binding antibody comprises an IgG, wherein said IgG is lgG1 , lgG2, lgG3, or lgG4.[000154] In some embodiments, the dual binding antibody described herein comprises an IgG immunoglobulin. In some embodiments, the dual binding antibody described hereincomprises an lgG1 immunoglobulin, an lgG2 immunoglobulin, an lgG3 immunoglobulin, or an lgG4 immunoglobulin. In some embodiments, the dual binding antibody comprises an lgG1 immunoglobulin. In some embodiments, the dual binding antibody comprises an lgG2 immunoglobulin. In some embodiments, the dual binding antibody comprises an lgG3 immunoglobulin. In some embodiments, the dual binding antibody comprises an lgG4 immunoglobulin. In some embodiments, the dual binding antibody comprises an lgG1 immunoglobulin or an lgG4 immunoglobulin.[000155] In some embodiments, the dual binding antibody described herein comprises an Fab immunoglobulin fragment. In some embodiments, the dual binding antibody described herein comprises an F(ab')2 immunoglobulin fragment. In some embodiments, the dual binding antibody described herein comprises an Fv immunoglobulin construct. In some embodiments, the dual binding antibody described herein comprises a scFv immunoglobulin construct. In some embodiments, the dual binding antibody described herein comprises a minibody immunoglobulin construct comprising a pair of single-chain Fv fragments which are linked via CH3 domains.[000156] In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises a heavy chain (HC) and a light chain (LC) comprising the VH / VL regions. In some embodiments, an isolated Trop2 / N ectin-4 dual binding antibody comprises an HC and an LC, wherein the amino acid sequence of the HC and LC pair comprises SEQ ID NOs: 802 and 804, respectively; SEQ ID NOs: 803 and 804, respectively; SEQ ID NOs: 805 and 807, respectively; SEQ ID NOs: 806 and 807, respectively; SEQ ID NOs: 808 and 810, respectively; or SEQ ID NOs: 809 and 810, respectively. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises an HC and an LC, wherein the amino acid sequences of the HC and LC pair comprise SEQ ID NOs: 802 and 804, respectively. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises an HC and an LC, wherein the amino acid sequence of the HC and LC pair comprise SEQ ID NOs: 803 and 804, respectively. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises an HC and an LC, wherein the amino acid sequences of the HC and LC pair comprise SEQ ID NOs: 805 and 807, respectively. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises an HC and an LC, wherein the amino acid sequences of the HC and LC pair comprise SEQ ID NOs: 806 and 807, respectively. In some embodiments, an isolated Trop2 / N ectin-4 dual binding antibodycomprises an HC and an LC, wherein the amino acid sequences of the HC and LC pair comprise SEQ ID NOs: 808 and 810, respectively. In some embodiments, an isolated Trop2 / Nectin-4 dual binding antibody comprises an HC and an LC, wherein the amino acid sequences of the HC and LC pair comprise SEQ ID NOs: 809 and 810, respectively.[000157] In some embodiments, the dual binding antibody described herein comprises a diabody immunoglobulin construct. In some embodiments, a diabody immunoglobulin construct comprises a heavy chain variable (VH) and light chain variable (VL) regions connected by a small peptide linker. In some embodiments, a diabody immunoglobulin construct comprises single-chain (Fv)2 in which two scFv fragments are covalently linked to each other. In some embodiments, the dual binding antibody described herein comprises a diabody immunoglobulin construct comprising three scFv fragments covalently linked to each other. Diabodies have been shown in the art to have dissociation constants up to 40- fold lower than corresponding scFvs, meaning that they have a much higher affinity to their target. Consequently, use of a diabody in a method of use as described herein, could result in much lower dosing of a diabody or triabody, than an IgG comprising the same VH and VL domains. Similarly, in some embodiments, a dual binding antibody comprises a triabody.[000158] In some embodiments, the dual binding antibodies are immune cell engagers. In some embodiments, immune cell engagers are engineered antibodies with at least one arm binding a tumor-associated antigen and at least one arm directed against an activating receptor in immune effector cells.[000159] In some embodiments, a Trop2 / Nectin-4 dual binding antibody comprises a multispecific immune cell engager, for example, a multi-engager.[000160] Dual binding antibodies may be used in several different mechanisms of action. In some embodiments, a Trop2 / Nectin-4 dual binding antibody may be comprised as part of an immune cell engager, a radiolabeled antibody, a cytokine conjugated antibody, or an Antibody Drug Conjugate (ADC). In some embodiments, a Trop2 / N ectin-4 dual binding antibody may be used for Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC), Antibody-Dependent Cellular Phagocytosis (ADCP), Complement Dependent Cytotoxicity (CDC), antibody-based delivery, direct neutralization, or any combination thereof.[000161] In some embodiments, the dual binding antibody comprising a linker or linkers between binding components, for example but not limited to between a VH and a VL in an scFv, a minibody, a diabody, a triabody, or a tetrabody. In some embodiments, the dualbinding antibody does not comprise a linker or linkers between binding components, for example, but not limited to, between a VH and a VL in an scFv, a minibody, a diabody, a triabody, or a tetrabody. In some embodiments, a linker may comprise a single amino acid. In some embodiments, a linker comprises any known linker in the art.[000162] A skilled artisan would appreciate that the term "variant" encompasses a polypeptide differing from other recited polypeptide sequences, for example the clone Trop2 / Nectin-4 variants disclosed herein.[000163] A skilled artisan would appreciate that an "isolated Trop2 / N ectin-4 dual binding antibody", in certain embodiments, encompasses an antibody that (1) is free of at least some other proteins with which it would typically be found in nature or with which it would typically be found during synthesis thereof, (2) is essentially free of other non-identical binding antibodies from the same source, (3) may be expressed recombinantly by a cell, (4) has been separated from at least about 50 percent of polynucleotides, lipids, carbohydrates, or other materials with which it is associated in during synthesis, or (5) does not occur in nature, or (6) a combination thereof. Such an isolated antibody may be encoded by genomic DNA, cDNA, mRNA, or other RNA, or maybe of synthetic origin, or any combination thereof. In certain embodiments, the isolated antibody is substantially free from proteins or polypeptides or other contaminants that would interfere with its use (therapeutic, diagnostic, prophylactic, research or otherwise). As used throughout, the terms “dual antibody” and “dual binding antibody” may be used interchangeably having all the same meanings and qualities.Compositions of Use[000164] In some embodiments, disclosed herein are compositions for therapeutic use. In some embodiments, a composition described herein comprises a Trop2 / Nectin-4 dual binding antibody or a Trop2 / Nectin-4 binding fragment thereof, as disclosed herein and a pharmaceutically acceptable carrier.[000165] As used herein, the terms “composition” and pharmaceutical composition” may in some embodiments, be used interchangeably having all the same qualities and meanings. In some embodiments, disclosed herein is a pharmaceutical composition for the treatment of a condition or disease as described herein. For example, but not limited to, cancer and immune-oncology disorders. In some embodiments, a cancer may be a solid tumor or a hematopoietic malignancy, an unresectable cancer, or a metastatic cancer, or acombination thereof. In some embodiments, a cancer may comprise a solid cancer. In some embodiments, a cancer may be a hematopoietic malignancy. In some embodiments, a cancer may be a cancer metastasis. In some embodiments, a cancer comprises an unresectable cancer. In some embodiments, a cancer comprises any combination of a solid tumor or a hematopoietic malignancy, or a metastatic cancer, or an unresectable cancer. [000166] In some embodiments, described herein are pharmaceutical compositions comprising a Trop2 / Nectin-4 dual binding antibody or a Trop2 / Nectin-4 dual binding fragment thereof, as described herein in detail. Pharmaceutical compositions comprising a T rop2 / Nectin-4 dual binding antibody or fragment thereof comprise a therapeutic agent that may be administered to a subject in need. In some embodiments, described herein are pharmaceutical compositions comprising the dual binding antibody or fragment thereof comprising a therapeutic agent comprising an Fc-mutated IgG unable to bind or having reduced binding to antibody-dependent cellular cytotoxicity components. In some embodiments, described herein are pharmaceutical compositions comprising a dual binding antibody having therapeutic properties against cancers, for example solid tumors and or hematopoietic malignancies, unresectable cancers, or metastases, or any combination thereof. In some embodiments, pharmaceutical compositions comprising a dual binding antibody have therapeutic properties for treating immune-oncology disorders.[000167] In some embodiments, a pharmaceutical composition comprises an isolated Trop2 / Nectin-4 dual binding antibody, as described herein and a pharmaceutically acceptable carrier. By pharmaceutically acceptable is meant a material that is not biologically or otherwise undesirable, i.e., the material can be administered to a subject without causing any undesirable biological effects or interacting in a deleterious manner with any of the other components of the pharmaceutical composition in which it is contained. As would be well-known to one of ordinary skill in the art, the carrier is selected to minimize any degradation of the polypeptides disclosed herein and to minimize any adverse side effects in the subject. The pharmaceutical compositions may be prepared by methodology well known in the pharmaceutical art.[000168] In some embodiments, a pharmaceutical composition comprises a dual binding antibody comprising a VH and a VL amino acid sequence as set forth in Tables 1 and 2, respectively, wherein the VH and VL are selected from the same clone. In certain embodiments, a pharmaceutical composition comprises any of the isolated dual bindingantibodies disclosed herein, and a pharmaceutically acceptable carrier.[000169] In some embodiments, a pharmaceutical composition comprises a dual binding antibody having HCDR1 , HCDR2 and HCDR3 as set forth in Tables 3A, 3B, and 3C, and LCDR1 , LCDR2 and LCDR3 as set forth in Tables 4A, 4B, and 4C, and a pharmaceutically acceptable carrier, wherein the HCDRs and LCDRs are selected from the same clone.[000170] A skilled artisan would recognize that a Trop2 / N ectin-4 dual binding antibody, described herein, may comprise an active ingredient of a pharmaceutical composition and may be used interchangeably with the term “drug” or “agent” having all the same meanings and qualities.[000171] In some embodiments, described herein are compositions comprising the dual binding antibody which may be administered in a variety of therapeutic settings.[000172] Administration of the dual binding antibodies described herein, in pure form or in an appropriate pharmaceutical composition, can be conducted via any of the accepted modes of administration of agents for serving similar utilities. The pharmaceutical compositions can be prepared by combining a dual binding antibody or a dual binding antibody-containing composition with an appropriate physiologically acceptable carrier, diluent, or excipient, and may be formulated into preparations in solid, semi-solid, liquid or gaseous forms, such as tablets, capsules, powders, granules, ointments, solutions, suppositories, injections, inhalants, gels, microspheres, and aerosols. In addition, other pharmaceutically active ingredients and / or suitable excipients such as salts, buffers and stabilizers may, but need not, be present within the composition. Administration may be achieved by a variety of different routes, including oral, parenteral, nasal, intravenous, intradermal, subcutaneous, or topical. In some embodiments, modes of administration depend upon the nature of the condition to be treated or prevented. An amount that, following administration, reduces, inhibits, prevents, or delays the progression and / or metastasis of a cancer is considered effective.[000173] A skilled artisan would appreciate that the phrases "physiologically acceptable carrier", "pharmaceutically acceptable carrier", "physiologically acceptable excipient", and "pharmaceutically acceptable excipient", may be used interchangeably may encompass a carrier, excipient, or a diluent that does not cause significant irritation to an organism and does not abrogate the biological activity and properties of the administered active ingredient. [000174] A skilled artisan would appreciate that an "excipient" may encompass an inertsubstance added to a pharmaceutical composition to further facilitate administration of an active ingredient. In some embodiments, excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives, gelatin, vegetable oils and polyethylene glycols.[000175] Techniques for formulation and administration of drugs are found in "Remington’s Pharmaceutical Sciences", Mack Publishing Co., Easton, PA, latest edition, which is incorporated herein by reference.[000176] In some embodiments, a pharmaceutical composition described herein comprises a nucleotide sequence encoding a dual binding antibody. In some embodiments, a nucleotide sequence encoding a dual binding antibody disclosed herein, comprises a single linear nucleotide sequence. In some embodiments, a nucleotide sequence encoding a dual binding antibody disclosed herein, comprises two nucleotide sequences. In some embodiments, a nucleotide sequence encoding a dual binding antibody disclosed herein, comprises two nucleotide sequences present on the same vector. In some embodiments, a nucleotide sequence encoding a dual binding antibody disclosed herein, comprises two nucleotide sequences present on different vectors.[000177] In some embodiments, a method of treating a subject in need, comprises a step of administering a pharmaceutical composition comprising a dual binding antibody comprising a VH domain comprising the amino acid sequence set forth in Table 1 , a VL domain comprising the amino acid sequence set forth in Table 2, and a pharmaceutically accepted carrier, to a subject in need, wherein the method treats the disease or condition.[000178] In some embodiments, the dual binding antibody is used as an agent for the diagnosis and treatment of a disease including, but not limited to, cancer. In some embodiments, the dual binding antibody is used for the monitoring of treatment response to a therapeutic or for the prognosis of a patient with diseases including, but not limited to, cancer. In some embodiments, the dual binding antibody is used as an imaging agent, immunohistochemistry (IHC) reagent and the like.[000179] In some embodiments, the dual binding antibody or fragment thereof is used in a diagnostic or prognostic method.Nucleotide Sequences Encoding CDR, VH and VL domains, and Vectors and Host Cells Comprising these Nucleotide Sequences[000180] In certain embodiments, disclosed herein are isolated polynucleotides encoding a dual binding antibody or dual binding fragment thereof, wherein the antibody or fragment thereof comprises three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1, HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 are selected from Tables 3A, 3B, 3C, 4A, 4B, and 4C, and wherein the CDR sequence set comprises the sequences of a single clone variant, and wherein the antibody or binding fragment thereof binds both antigens within the same Fv region.[000181] In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise:(a) SEQ ID NO: 791, SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 814, SEQ ID NO: 815, SEQ ID NO: 816, SEQ ID NO: 817, SAS, and SEQ ID NO: 819, respectively;(c) SEQ ID NO: 820, SEQ ID NO: 821, SEQ ID NO: 822, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(d) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(e) SEQ ID NO: 823, SEQ ID NO: 824, SEQ ID NO: 825, SEQ ID NO: 826, SAS, and SEQ ID NO: 828, respectively;(f) SEQ ID NO: 829, SEQ ID NO: 830, SEQ ID NO: 831, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(g) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively;(h) SEQ ID NO: 832; SEQ ID NO: 833; SEQ ID NO: 834, SEQ ID NO: 835, SAS, and SEQ ID NO: 837, respectively; or(i) SEQ ID NO: 838; SEQ ID NO: 839; SEQ ID NO: 840, SEQ ID NO: 796, SEQ ID NO:798, and SEQ ID NO: 800, respectively.[000182] In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively. In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1, HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1, HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise SEQ ID NO: 814, SEQ ID NO: 815, SEQ ID NO: 816, SEQ ID NO: 817, SAS, and SEQ ID NO: 819, respectively. In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3 comprise SEQ ID NO: 820, SEQ ID NO: 821, SEQ ID NO: 822, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801, respectively. In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1, HCDR2, and HCDR3 and three light chain complementarity determining regions CDRs LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1, HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively. In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acidsequences of the HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise SEQ ID NO: 823, SEQ ID NO: 824, SEQ ID NO: 825, SEQ ID NO: 826, SAS, and SEQ ID NO: 828. In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1, HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise SEQ ID NO: 829, SEQ ID NO: 830, SEQ ID NO: 831, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;. In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1, HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1, HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively. In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise SEQ ID NO: 832; SEQ ID NO: 833; SEQ ID NO: 834, SEQ ID NO: 835, SAS, and SEQ ID NO: 837, respectively. In some embodiments, an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise SEQ ID NO: 838; SEQ ID NO: 839; SEQ ID NO: 840, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.[000183] In some embodiments disclosed herein is an isolated polynucleotide encoding a dual binding antibody or dual binding fragment thereof, wherein the antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1 ,HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1, HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise:(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(c) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.[000184] In some embodiments, the present disclosure provides isolated polynucleotide sequences encoding a heavy chain variable region of a Trop2 / N ectin-4 antibody, wherein the heavy chain variable region comprises the amino acid sequence set forth in Table 1. In another embodiment, the present disclosure also provides a vector comprising the above- mentioned polynucleotide sequences. In view of the amino acid sequences disclosed herein, one of ordinary skill in the art would readily construct a vector or plasmid to encode for the amino acid sequences. In another embodiment, the present disclosure also provides a host cell comprising the vector provided herein. Depending on the uses and experimental conditions, one of skill in the art would readily employ a suitable host cell to carry and / or express the above-mentioned polynucleotide sequences.[000185] In some embodiment, the present disclosure provides an isolated polynucleotide sequence encoding a light chain variable region of a Trop2 / N ectin-4 antibody, wherein the light chain variable region comprises the amino acid sequence set forth in Table 2. In other embodiments, the present disclosure also provides a vector comprising the above- mentioned polynucleotide sequences. In view of the amino acid sequences disclosed herein, one of ordinary skill in the art would readily construct a vector or plasmid to encode for the amino acid sequences. In another embodiment, the present disclosure also provides a host cell comprising the vector provided herein. Depending on the uses and experimental conditions, one of skill in the art would readily employ a suitable host cell to carry and / or express the above-mentioned polynucleotide sequences.[000186] In some embodiment, the present disclosure provides an isolated polynucleotide sequence encoding a dual binding Trop2 / Nectin-4 antibodies or dual binding fragments thereof comprising VH and VL sequences that are at least 90% (e.g., at least 90%, 95%,96%, 97%, 98%, or 99%) identical to the VH and VL sequences set forth above and as disclosed in Tables 1 and 2. One skilled in the art would appreciate that percent sequence identity may be determined using any of a number of publicly available software application, for example but not limited to BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters.[000187] In some embodiments of a polynucleotide encoding a dual binding Trop2 / Nectin- 4 antibodies or dual binding fragments thereof comprising a heavy chain variable region (VH) and a light chain variable region (VL), the amino acid sequences for the heavy chain variable region and the light chain variable region are set forth in any of the VH / VL sets presented for the antibodies of Tables 1 and 2, or comprise homologous sequences that are at least 90% (e.g., at least 90%, 95%, 96%, 97%, 98%, or 99%) identical to the VH and VL sequences set forth in Tables 1 and 2.[000188] In view of the sequences for the heavy chain variable regions and light chain variable regions disclosed herein, one of ordinary skill in the art would readily employ standard techniques known in the art to construct a Trop2 / Nectin-4 scFv. In some embodiments, the present disclosure provides an isolated polynucleotide sequence encoding a heavy chain variable region of a Tro p2 / N ectin-4 antibody and a light chain variable region of a Trop2 / Nectin-4 antibody, wherein the heavy chain variable region comprises the amino acid sequence set forth in Table 1 and the light chain variable region comprises the amino acid sequence set forth in Table 2.[000189] In certain embodiments, an isolated polynucleotide construct encodes the VH and VL regions of a Trop2 / N ectin-4 dual binding antibody, wherein the polynucleotide encodes the VH and VL regions comprising the amino acid sequences as set forth in Table 1 and Table 2, respectively, and wherein the amino acid sequences for VH and VL are selected from the same clone variant.[000190] In certain embodiments, an isolated polynucleotide construct encodes the VH and VL regions of a T rop2 / Nectin-4 dual binding antibody or a binding fragment thereof, wherein the polynucleotide encodes the VH and VL regions comprising the amino acid sequences comprising(a) SEQ ID NOs: 787 and 789, respectively;(b) SEQ ID NOs: 20 and 118, respectively; or(c) SEQ ID NOs: 786 and 788, respectively.[000191] In some embodiments, an isolated polynucleotide construct encodes the VH and VL regions of a T rop2 / Nectin-4 dual binding antibody or a binding fragment thereof , wherein the polynucleotide encodes the VH and VL regions comprising the amino acid sequences comprising SEQ ID NOs: 787 and 789, respectively. In some embodiments, an isolated polynucleotide construct encodes the VH and VL regions of a Trop2 / Nectin-4 dual binding antibody or a binding fragment thereof, wherein the polynucleotide encodes the VH and VL regions comprising the amino acid sequences comprising SEQ ID NOs: 20 and 118, respectively. In some embodiments, an isolated polynucleotide construct encodes the VH and VL regions of a Trop2 / Nectin-4 dual binding antibody or a binding fragment thereof, wherein the polynucleotide encodes the VH and VL regions comprising the amino acid sequences comprising SEQ ID NOs: 786 and 788, respectively.[000192] In some embodiments, an isolated polynucleotide construct encodes a Trop2 / Nectin-4 dual binding scFv antibody-binding fragment, the amino acid sequence of the scFv antibody-binding fragment comprising(a) SEQ ID NO: 811 ;(b) SEQ ID NO: 812; or(c) SEQ ID NO: 813.[000193] In some embodiments, an isolated polynucleotide construct encodes a Trop2 / Nectin-4 dual binding scFv antibody-binding fragment, the amino acid sequence of the scFv antibody-binding fragment comprising SEQ ID NO: 811. In some embodiments, an isolated polynucleotide construct encodes a Trop2 / Nectin-4 dual binding scFv antibodybinding fragment, the amino acid sequence of the scFv antibody-binding fragment comprising SEQ ID NO: 812. In some embodiments, an isolated polynucleotide construct encodes a Trop2 / Nectin-4 dual binding scFv antibody-binding fragment, the amino acid sequence of the scFv antibody-binding fragment comprising SEQ ID NO: 813.[000194] In some embodiments, an isolated polynucleotide construct encodes a Trop2 / Nectin-4 antibody or fragment thereof, wherein said antibody or fragment thereof is in the form of an IgG, an Fv, an scFv, an Fab, a F(ab')2, a minibody, a diabody, a triabody, an immune-cell engager, a multi-specific antibody, or a multi-engager; and wherein optionally said IgG comprises an lgG1 , lgG2, lgG3, or lgG4.[000195] In some embodiments, a vector comprises the polynucleotide sequence encoding the VH and VL regions of a Trop2 / Nectin-4 dual binding antibody. In some embodiments, ahost cell comprises a vector comprising the polynucleotide sequence encoding VH and VL regions of a Trop2 / Nectin-4 scFv.[000196] In another embodiment, the present disclosure provides a vector comprising the above-mentioned polynucleotide sequences. In view of the amino acid sequences disclosed herein, one of ordinary skill in the art would readily construct a vector or plasmid to encode for the amino acid sequences. In another embodiment, the present disclosure also provides a host cell comprising the vector provided herein. Depending on the uses and experimental conditions, one of skill in the art would readily employ a suitable host cell to carry and / or express the above-mentioned polynucleotide sequences.[000197] In view of the sequences for the heavy chain variable regions and light chain variable regions disclosed herein, one of ordinary skill in the art would readily employ standard techniques known in the art to construct a Trop2 / Nectin-4 dual binding scFv.[000198] In certain embodiments, the term "isolated polynucleotide" shall mean a polynucleotide of genomic, cDNA, or synthetic origin, or some combination thereof, which by virtue of its origin the isolated polynucleotide (1) is not associated with all or a portion of a polynucleotide in which the isolated polynucleotide is found in nature, (2) is linked to a polynucleotide to which it is not linked in nature, (3) does not occur in nature as part of a larger sequence, or (4) a combination thereof.Methods of Synthesizing an Engineered Trop2 / Nectin-4 Dual Binding Antibody[000199] In some embodiments, described herein is a method of producing a Trop2 / Nectin- 4 dual binding antibody comprising HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 domains, as described herein. In some embodiments, the amino acid sequences of the HCDR1, HCDR2, HCDR3 regions are set forth in Tables 3A, 3B, and 3C. In some embodiments, the amino acid sequences of the LCDR1, LCDR2, LCDR3 regions are set forth in Tables 4A, 4B, and 4C. In some embodiments, the skilled artisan would recognize to produce the HCDR sets and LCDR sets from the same clone variant.[000200] In some embodiments, described herein is a method of producing a Trop2 / Nectin- 4 dual binding antibody comprising a VH domain and a VL domain, as described herein. In some embodiments, the amino acid sequence of the VH domain is set forth in Table 1 and the amino acid sequence of the VL domain is set forth in Table 2, wherein the skilled artisan would recognize selecting VH and VL regions from the same clone variant.[000201] In some embodiments, a method of producing a Trop2 / Nectin-4 dual binding antibody comprises steps of culturing cells comprising a nucleic acid sequence encoding at least a VH and a VL of the dual binding antibody, wherein polypeptides comprising the VH and VL domains are expressed and isolated, and wherein said isolated VH and VL domains form a heterodimer. As disclosed herein, the isolated nucleic acid sequences encoding VH and VL domains may be comprised within vectors, wherein the same vector or different vectors are used. In some embodiments, each VH domain and VL domain may be expressed from a different host cell, wherein dimerization occurs following isolation or purification of the component VH and VL domains. In some embodiments VH and VL domains may be expressed from a same host cell, wherein dimerization occurs in culture or following isolation or purification of the component VH and VL domains. In some embodiments, a dual binding antibody may be produced as a scFv. In some embodiments, a dual binding antibody may be produced as an IgG. In some embodiments, a dual binding antibody may be produced part of a recombinant construct.[000202] In some embodiments, systems for cloning and expression of a polypeptide, e.g., an anti-Trop2 / Nectin-4 dual binding antibody or an anti-Trop2 / Nectin-4 dual binding fragment thereof, in a variety of different host cells are well known. Suitable host cells can include, without limitation, prokaryotic cells, fungal cells, yeast cells, or higher eukaryotic cells such as insect cells or mammalian cells.[000203] Suitable prokaryotic cells for this purpose include, without limitation, eubacteria, such as Gram-negative or Gram-positive organisms, for example, Enterobactehaceae such as Escherichia, e.g., E. coli, Enterobacter, Erwinia, Klebsiella, Proteus, Salmonella, e.g., Salmonella typhimurium, Serratia, e.g., Serratia marcescans, and Shigella, as well as Bacilli such as B. subtilis and B. licheniformis, Pseudomonas such as P. aeruginosa, and Streptomyces.[000204] The expression of antibodies and antigen-binding fragments thereof in prokaryotic cells such as E. coli is well established in the art. For a review, see for example Pluckthun, A. Bio / Technology 9: 545-551 (1991). Expression in eukaryotic cells in culture is also available to those skilled in the art as an option for production of antibodies or antigenbinding fragments thereof, see reviews, for example Ref, M. E. (1993) Curr. Opinion Biotech. 4: 573-576; Trill J. J. et al. (1995) Curr. Opinion Biotech 6: 553-560.[000205] Suitable fungal cells for this purpose include, without limitation, filamentous fungi and yeast. Illustrative examples of fungal cells include, Saccharomyces cerevisiae, common baker's yeast, Schizosaccharomyces pombe, Kluyveromyces hosts such as, eg., K. lactis, K. fragilis (ATCC 12,424), K. bulgaricus (ATCC 16,045), K. wickeramii (ATCC 24,178), K. waltii (ATCC 56,500), K. drosophilarum (ATCC 36,906), K. thermotolerans, and K. marxianus', yarrowia (EP 402,226); Pichia pastoris (EP 183,070); Candida; Trichoderma reesia (EP 244,234); Neurospora crassa., Schwanniomyces such as Schwa nniomyces occidentalis’, and filamentous fungi such as, e.g., Neurospora, Penicillium, Tolypocladium, and Aspergillus hosts such as A. nidulans and A. niger.[000206] Higher eukaryotic cells, in particular, those derived from multicellular organisms can be used for expression of glycosylated antibodies or fragments thereof, e.g., VH and VL domains, as provided herein. Suitable higher eukaryotic cells include, without limitation, invertebrate cells and insect cells, and vertebrate cells. Examples of invertebrate cells include plant and insect cells. Numerous baculoviral strains and variants and corresponding permissive insect host cells from hosts such as Spodoptera frugiperda (caterpillar), Aedes aegypti (mosquito), Aedes albopictus (mosquito), Drosophila melanogaster (fruiffly), and Bombyx mori have been identified. A variety of viral strains for transfection are publicly available, e.g., the K-1 variant of Autographa californica NPVand the Bm-5 strain of Bombyx mori NPV, and such viruses may be used as the virus herein as described herein, particularly for transfection of Spodoptera frugiperda cells. Plant cell cultures of cotton, corn, potato, soybean, petunia, tomato, and tobacco can also be utilized as hosts. Mammalian cell lines available in the art for expression of a heterologous polypeptide include but are not limited to Chinese hamster ovary (CHO) cells, HeLa cells, baby hamster kidney cells, NS0 mouse melanoma cells, YB2 / 0 rat myeloma cells, human embryonic kidney cells, human embryonic retina cells and many others. Non-limiting examples of vertebrate cells include mammalian host cell lines such as monkey kidney CV1 line transformed by SV40 (COS-7, ATCC CRL 1651); human embryonic kidney line (293 or 293 cells subcloned for growth in suspension culture, Graham et al., J. Gen Virol. 36:59 (1977)); baby hamster kidney cells (BHK, ATCC CCL 10); Chinese hamster ovary cells / -DHFR (CHO, llrlaub et al., Proc. Natl. Acad. Sci. USA 77:4216 (1980)); ExpiCHO-S(TM) cells (ThermoFisher Scientific cat. #A29133); mouse Sertoli cells (TM4, Mather, Biol. Reprod. 23:243-251 (1980)); monkey kidney cells (CV1 ATCC CCL 70); African green monkey kidney cells (VERO-76, ATCCCRK-1587); human cervical carcinoma cells (HELA, ATCC CCL 2); canine kidney cells (MDCK, ATCC CCL 34); buffalo rat liver cells (BRL 3A, ATCC CRL 1442); human lung cells (W138, ATCC CCL 75); human liver cells (Hep G2, HB 8065); mouse mammary tumor (MMT 060562, ATCC CCL51); TRI cells (Mather et al., Annals N.Y. Acad. Sci. 383:44-68 (1982)); MRC 5 cells; FS4 cells; and a human hepatoma line (Hep G2).[000207] A skilled artisan would appreciate that producing a dual binding antibody comprises synthesizing amino acid polypeptide components comprising VH domains, VL domains, or both. In some embodiments, said synthesis starts from a nucleic acid construct. The terms “producing” and “synthesizing” may in some embodiments, be used herein interchangeably having all the same qualities and meanings.[000208] In some embodiments, synthesizing a dual binding antibody comprises synthesizing an IgG heavy chain comprising a VH domain, synthesizing an IgG light chain comprising a VL domain, or both. In some embodiments, synthesizing a dual binding antibody comprises synthesizing both an IgG heavy chain comprising a VH domain and an IgG light chain comprising a VL domain. In some embodiments, synthesizing a dual binding antibody comprises synthesizing a Fab comprising a fragment of an IgG heavy chain comprising a VH domain and a fragment of an IgG light chain comprising a VL domain. In some embodiments, synthesizing a dual binding antibody comprises synthesizing an F(ab 2 comprising a fragment of an IgG heavy chain comprising a VH domain and a fragment of an IgG light chain comprising a VL domain. In some embodiments, synthesizing a dual binding antibody comprises synthesizing an Fv comprising a VH domain and a VL domain. In some embodiments, synthesizing a dual binding antibody comprises synthesizing a scFv comprising a VH domain and a VL domain. In some embodiments, synthesizing a dual binding antibody comprises synthesizing a minibody comprising a VH domain and a VL domain. In some embodiments, synthesizing a dual binding antibody comprises synthesizing a diabody comprising a VH domain and a VL domain. In some embodiments, synthesizing a dual binding antibody comprises synthesizing a triabody comprising a VH domain and a VL domain. In some embodiments, synthesizing a dual binding antibody comprises synthesizing a T cell or NK cell engager, wherein one arm of a IgG engager comprises a VH domain and a VL domain.[000209] In certain embodiments, the polypeptide expressed in the host cell can form a dimer and thus produce a dual binding antibody or the binding component thereof.[000210] In certain embodiments, the VH and VL domains may be comprised within longer polypeptide sequences, which may include for example but not limited to constant regions, hinge regions, linker regions, Fc regions, or disulfide binding regions, or any combination thereof. A constant domain is an immunoglobulin fold unit of the constant part of an immunoglobulin molecule, also referred to as a domain of the constant region (e.g., CH1 , CH2, CH3, CH4, Ck, Cl). In some embodiments, the longer polypeptide may comprise multiple copies of a VH domain, a VL domain, or both, for example but not limited to when the dual binding antibody comprises a diabody or a triabody.[000211 ] In certain embodiments, the VH and VL domains are generated by DNA synthesis and PCR, and translation of nucleotide sequences generated thereof. In certain embodiments, the generated sequences may be subcloned into an expression vector. In certain embodiments, the generated sequences may be subcloned into two expression vectors. In certain embodiments, said expression vector is a plasmid.[000212] In certain embodiments, transient expression is performed by co-transfecting the expression vector encoding the VH and VL domains or by transfecting an expression vector encoding both into a suitable cell. A skilled artisan would appreciate that there are a number of transfection methods and protocols that can be used for this purpose. In certain embodiments, transfection or co-transfection is executed using the PEI method.[000213] The expressed polypeptides comprising the VH and VL domains and / or the polypeptide complex can be collected using any suitable methods. The VH and VL domains and / or the polypeptide complex can be expressed intracellularly, in the periplasmic space or be secreted outside of the cell into the medium. If the polypeptides comprising VH and VL domains and / or the polypeptide complex is expressed intracellularly, the host cells containing the polypeptides comprising VH and VL domains and / or the polypeptide complex may be lysed and polypeptide and / or the polypeptide complex may be isolated from the lysate by removing the unwanted debris by centrifugation or ultrafiltration. If the polypeptides comprising VH and VL domains and / or the polypeptide complex is secreted into periplasmic space of E. coli, the cell paste may be thawed in the presence of agents such as sodium acetate (pH 3.5), EDTA, and phenylmethylsulfonylfluoride (PMSF) over about 30 min, and cell debris can be removed by centrifugation (Carter et al., BioTechnology 10:163-167 (1992)). If the polypeptides comprising VH and VL domains and / or the polypeptide complex is secreted into the medium, the supernatant of the cell culture may be collected andconcentrated using a commercially available protein concentration filter, for example, an Amincon or Millipore Pellicon ultrafiltration unit. A protease inhibitor and / or an antibiotic may be included in the collection and concentration steps to inhibit protein degradation and / or growth of contaminated microorganisms.[000214] The expressed polypeptides comprising VH and VL domains and / or the polypeptide complex can be further purified by a suitable method, such as without limitation, affinity chromatography, hydroxylapatite chromatography, size exclusion chromatography, gel electrophoresis, dialysis, ion exchange fractionation on an ion-exchange column, ethanol precipitation, reverse phase HPLC, chromatography on silica, chromatography on heparin sepharose, chromatography on an anion or cation exchange resin (such as a polyaspartic acid column), chromatofocusing, SDS-PAGE, and ammonium sulfate precipitation (see, for review, Bonner, P. L., Protein purification, published by Taylor & Francis, 2007; Janson, J. C., et al, Protein purification: principles, high resolution methods and applications, published by Wiley-VCH, 1998).[000215] In certain embodiments, the polypeptides comprising VH and VL domains and / or polypeptide dimer complexes can be purified by affinity chromatography. In certain embodiments, protein A chromatography or protein A / G (fusion protein of protein A and protein G) chromatography can be useful for purification of polypeptides and / or polypeptide complexes comprising a component derived from antibody CH2 domain and / or CH3 domain (Lindmark et al., J. Immunol. Meth. 62:1-13 (1983); Zettlit, K. A., Antibody Engineering, Part V, 531-535, 2010). In certain embodiments, a dual binding antibody disclosed herein does not bind to protein A. In certain embodiments, protein G chromatography can be useful for purification of polypeptides and / or polypeptide complexes comprising lgGy3 heavy chain (Guss et al., EMBO J. 5:1567 1575 (1986)). In certain embodiments, protein L chromatography can be useful for purification of polypeptides and / or polypeptide complexes comprising K light chain (Sudhir, P., Antigen engineering protocols, Chapter 26, published by Humana Press, 1995; Nilson, B. H. K. et al, J. Biol. Chem., 267, 2234-2239 (1992)). The matrix to which the affinity ligand is attached is most often agarose, but other matrices are available. Mechanically stable matrices such as controlled pore glass or poly(styrenedivinyl)benzene allow for faster flow rates and shorter processing times than can be achieved with agarose. Where the antibody comprises a CH3 domain, the Bakerbond ABX resin (J. T. Baker, Phillipsburg, N.J.) is useful for purification.[000216] Following any preliminary purification step(s), the mixture comprising the dual binding antibody and contaminants may be subjected to low pH hydrophobic interaction chromatography using an elution buffer at a pH between about 2.5-4.5, preferably performed at low salt concentrations (e.g., from about 0-0.25M salt).[000217] In certain embodiments, the polypeptides comprising VH and VL domains and / or polypeptide dimer complexes can be purified by affinity chromatography and size exclusion chromatography (SEC). A skilled artisan would appreciate that there are a number of methods and protocols suitable for this purpose. In certain embodiments, protein purification by affinity chromatography and SEC is performed using an AKTA pure instrument (GE Lifesciences). In certain embodiments, affinity capture of the dual binding antibody is achieved by passing the harvested supernatants over a column of CaptureSelect™ CH1- XL Affinity Matrix (Thermo Scientific). After washing column with PBS, the protein is eluted with 0.1M Glycine, pH 2.5, and immediately neutralized with 1 / 6 volume of 1 M Tris-HCI, pH 8.0. The affinity purified protein is then concentrated to 5-10mg / ml using Amicon 30kD concentrator (Merck Millipore) and subjected to SEC purification on a Superdex®200 column (GE Lifesciences) equilibrated with PBS. Protein fractions are then collected and analyzed using SDS-PAGE and HPLC-SEC.[000218] Binding to an epitope of the synthesized dual binding immunoglobulins may be analyzed using well known methods in the art, as described herein, including ELISA analysis, SPR analysis, DSF analysis, and cell-based binding assays.[000219] In some embodiments, a method of synthesizing a dual binding antibody comprising: a heavy chain variable region comprises the amino acid sequence set forth in Table 1 and a light chain variable region set forth in Table 2.[000220] As described herein and exemplified below, in some embodiments, that antibody synthesized comprises an IgG immunoglobulin. In some embodiments, the antibody synthesized comprises an lgG1 immunoglobulin, an lgG2 immunoglobulin, an lgG3 immunoglobulin, or an lgG4 immunoglobulin. In some embodiments, the antibody synthesized comprises an lgG1 immunoglobulin. In some embodiments, the antibody synthesized comprises an lgG2 immunoglobulin. In some embodiments, the antibody synthesized comprises an lgG3 immunoglobulin. In some embodiments, the antibody synthesized comprises an lgG4 immunoglobulin. In some embodiments, the antibodysynthesized comprises an lgG1 immunoglobulin or an lgG4 immunoglobulin.[000221] In some embodiments, the antibody synthesized comprises a Fab immunoglobulin fragment. In some embodiments, the antibody synthesized comprises an F(ab')2 immunoglobulin fragment. In some embodiments, the antibody synthesized comprises an Fv immunoglobulin construct. In some embodiments, the antibody synthesized comprises an scFv immunoglobulin construct. In some embodiments, the antibody synthesized comprises a T-cell or NK-cell engager immunoglobulin construct. In some embodiments, the antibody synthesized comprises a minibody immunoglobulin construct comprising a pair of single-chain Fv fragments which are linked via CH3 domains.[000222] In some embodiments, the antibody synthesized comprises a diabody immunoglobulin construct. In some embodiments, the antibody synthesized comprises a diabody immunoglobulin construct comprising three scFv fragments covalently linked to each other. In some embodiments, the antibody synthesized comprises a triabody.[000223] In some embodiments, the antibody synthesized comprises a Fc-mutated IgG that is unable to bind or has reduced binding to antibody-dependent cellular cytotoxicity components. In some embodiments, the antibody synthesized comprises a Fc-mutated I gG 1 that is unable to bind or has reduced binding to antibody-dependent cellular cytotoxicity components.Methods of Use[000224] In some embodiments, the Trop2 / Nectin-4 dual binding antibodies of the present disclosure can be used as immunotherapeutic agents, for example, for treating a subject in need. These dual binding antibodies can be administered to a subject directly, or by administering to the subject a nucleic acid sequence encoding polypeptide(s) comprising the VH and VL domains of the dual binding antibodies, such nucleic acid sequence may be carried by a vector.[000225] In certain embodiments, disclosed herein is a method of treating a subject suffering from a disease or condition, said method comprising administering to said subject a composition comprising an isolated Trop2 / Nectin-4 dual binding antibody as described herein. In certain embodiments, disclosed herein is a method of treating a subject suffering from a disease or condition, said method comprising administering to said subject an isolated Trop2 / Nectin-4 dual binding antibody as described herein.[000226] The exact amount of the present polypeptides or compositions thereof required toelicit the desired effects will vary from subject to subject, depending on the species, age, gender, weight, and general condition of the subject, the particular polypeptides, the route of administration, and whether other drugs are included in the regimen. Thus, it is not possible to specify an exact amount for every composition. However, an appropriate amount can be determined by one of ordinary skill in the art using routine experimentation. Dosages can vary, and the polypeptides can be administered in one or more (e.g., two or more, three or more, four or more, or five or more) doses daily, for one or more days. Guidance in selecting appropriate doses for antibodies can be readily found in the literature.[000227] In some embodiments of a methods of use of a Trop2 / Nectin-4 dual binding antibody described herein; a subject comprises a mammalian subject. In some embodiments, a subject comprises a human subject. In some embodiments, a subject suffers from cancer or a tumor.[000228] The dual binding antibodies described herein bind to both Trop2 and Nectin-4, allowing a broad number of tumor indications to be targeted. In some embodiments, the tumor type co-expresses Trop2 and Nectin4. In some embodiments, the tumor type can express both high Trop2 and high Nectin-4 levels. In some embodiments, the tumors may express high T rop2 and moderate levels of Nectin-4. In some embodiments, the tumors may express high T rop2 and low Nectin-4 levels. In some embodiments, the tumors may express high Trop2 but no Nectin-4. In some embodiments, the tumors may express moderate Trop2 and elevated levels of Nectin-4. In some embodiments, the tumors may express moderate Trop2 and moderate Nectin-4 levels. In some embodiments, the tumors may express moderate Trop2 but low levels of Nectin-4. In some embodiments, the tumors may express moderate T rop2 but no Nectin-4. In some embodiments, the tumors may express low T rop2 and elevated levels of Nectin-4. In some embodiments, the tumors may express low Trop2 and moderate Nectin-4 levels. In some embodiments, the tumors may express low Trop2 but low levels of Nectin-4. In some embodiments, the tumors may express lowTrop2 but no levels of Nectin-4. In some embodiments, the tumors may express no Trop2 and elevated levels of Nectin-4. In some embodiments, the tumors may express no Trop2 and moderate Nectin-4 levels. In some embodiments, the tumors may express no Trop2 but low levels of Nectin-4.[000229] Expression of both Trop2 and Nectin-4 can be quantified through using methods known in the art examining mRNA transcript levels, Proteomic analysis,Immunohistochemistry (IHC), Immunofluorescence Histology, Immunofluorescence Microscopy, Flow Cytometry, Laser Scanning Cytometry, Confocal Microscopy, Multiphoton Microscopy, Super- Resolution Microscopy (STED, PALM, STORM), Total Internal Reflection Fluorescence Microscopy (TIRF), In Vivo Imaging, Digital Spatial Profiling, Single-Cell Proteomics, Spatial Transcriptomics, Mass Cytometry (CyTOF), Barcode Sequencing (Bar-Seq), Spatially Resolved Transcriptomics, Quantitative PCR (qPCR) / Real-Time PCR, Reverse Transcription PCR (RT-PCR), Northern Blotting, RNA-Seq (RNA Sequencing), Microarray Analysis, Digital Droplet PCR (ddPCR), Nanostring nCounter, In Situ Hybridization (ISH), Single-cell RNA Sequencing (scRNA-seq), Western Blotting, Enzyme-Linked Immunosorbent Assay (ELISA), Mass Spectrometry (MS), Tandem Mass Tag (TMT) Labeling, Stable Isotope Labeling by / with Amino acids in Cell culture (SILAC), Protein Microarray, Surface Plasmon Resonance (SPR), ProximityProximity Ligation Assay (PLA), Bioluminescence Resonance Energy Transfer (BRET), Fluorescence Resonance Energy Transfer (FRET), Tandem Mass Tag (TMT) Labeling, Chromatin Immunoprecipitation (ChIP), Chromatin Immunoprecipitation Sequencing (ChlP-Seq), Ribosome Profiling, Single Molecule Real-Time (SMRT) Sequencing, NanoString Technologies, Droplet-Based Microfluidics, Cytometry by Time of Flight (CyTOF), Proximity Extension Assay (PEA), Capillary Electrophoresis, Bioinformatics Analysis of RNA-Seq Data, Gene Expression Omnibus (GEO) Data Mining, Pathway Enrichment Analysis, Proteomics Data Integration, or Machine Learning Models for Gene Expression Prediction, or a combination of these.[000230] In some embodiments, disclosed herein is a method of treating a subject suffering from a disease or condition comprises administering to the subject a composition comprising an isolated Trop2 / N ectin-4 dual binding antibody, as described herein. In some embodiments, disclosed herein is a method of treating a subject suffering from a disease or condition comprises administering to the subject an isolated Trop2 / Nectin-4 dual binding antibody, as described herein.[000231 ] In some embodiments, “treating a subject” refers to both therapeutic treatment and prophylactic or preventative measures, wherein the object is to prevent or lessen the targeted pathologic condition or disorder as described hereinabove. Thus, in one embodiment, treating may include directly affecting or curing, suppressing, inhibiting, preventing, reducing the severity of, delaying the onset of, reducing symptoms associatedwith the disease, disorder or condition, or a combination thereof. Thus, in one embodiment, “treating” refers inter alia to delaying progression, expediting remission, inducing remission, augmenting remission, speeding recovery, increasing efficacy of or decreasing resistance to alternative therapeutics, or a combination thereof. In one embodiment, “preventing” refers, inter alia, to delaying the onset of symptoms, preventing relapse to a disease, decreasing the number or frequency of relapse episodes, increasing latency between symptomatic episodes, or a combination thereof. In one embodiment, “suppressing” or “inhibiting”, refers inter alia to reducing the severity of symptoms, reducing the severity of an acute episode, reducing the number of symptoms, reducing the incidence of disease-related symptoms, reducing the latency of symptoms, ameliorating symptoms, reducing secondary symptoms, reducing secondary infections, prolonging patient survival, or a combination thereof.[000232] In some embodiments of a method of treating a disease or condition, the disease or condition is a cancer or an immune-oncology disorder. In some embodiments of treating a disease or condition, the disease or condition comprises cancer. In some embodiments, the cancer comprises a solid tumor, a hematopoietic malignancy, or an unresectable cancer, or a metastatic cancer, or a combination thereof. In some embodiments, the cancer comprises a solid tumor. In some embodiments, the cancer comprises a hematopoietic malignancy. In some embodiments, the cancer comprises an unresectable cancer. In some embodiments, the cancer comprises a metastatic cancer.[000233] In some embodiments of a method of treating a tumor, the tumor expresses Trop2 and Nectin-4 on its cell surface. In other embodiments, the tumor expresses Trop2 but not Nectin-4 on its cell surface. And in yet other embodiments, the tumor expresses Nectin-4 but not Trop2 on its cell surface.[000234] A skilled artisan would appreciate that expression of Trop2 and Nectin-4 mRNA correlates with the presence of these antigens on the cell surface of cancer cells.[000235] Variable levels of Trop2 and / or Nectin-4 expression can be found in cancers including but not limited to cancers of the lung cancer; breast including but not limited to triple-negative breast cancer (TNBC), hormone receptor positive breast cancer, and Hempositive breast cancer; gastrointestinal tract cancers for example cancer of the colon, rectum, or small intestine); esophageal cancer; brain cancer (including gliomas, meningiomas); kidney cancer (renal cell carcinoma); liver cancer (hepatocellularcarcinoma); reproductive tract (male and female, including testicular cancer, / seminal vesicle cancer, and cervical cancer, endometrial cancer, uterine cancer, ovarian cancer,), endocrine system cancer; myeloid system cancer; skin cancer; thymus cancer; thyroid cancer; pancreatic cancer; stomach cancer; tracheal cancer; nasopharyngeal cancer; laryngeal cancer; gallbladder cancer; anal cancer; spinal cord cancer; bladder cancer; urothelial cancer; ureter cancer; urethral cancer; prostate cancer; penile cancer; vaginal cancer; vulvar cancer; thyroid cancer; parathyroid cancer; adrenal gland cancer (adrenocortical carcinoma); pituitary gland tumors; pancreatic neuroendocrine tumors (PNETs); melanoma; basal cell carcinoma; squamous cell carcinoma; Merkel cell carcinoma; Kaposi sarcoma; myeloid cancers; acute myeloid leukemia (AML); chronic myeloid leukemia (CML); lymphoid cancers; Hodgkin lymphoma; non-Hodgkin lymphoma; multiple myeloma; acute lymphoblastic leukemia (ALL); chronic lymphocytic leukemia (CLL); musculoskeletal system related cancers; bone cancer (osteosarcoma; Ewing sarcoma, chondrosarcoma; soft tissue sarcomas (liposarcoma, rhabdomyosarcoma, leiomyosarcoma); lymphatic system related cancers; lymphangiosarcoma; thymoma; thymic carcinoma; head and neck cancers; for example but not limited to head and neck squamous cell carcinoma (HNSCC); oral cancer; oropharyngeal cancer; hypopharyngeal cancer; salivary gland cancer; retinoblastoma;; ocular melanoma; mesothelioma (cancer of the mesothelium, often linked to asbestos exposure);neuroendocrine tumors; gastrointestinal stromal tumors (GIST); hepatoblastoma; and cholang iocarcinoma (bile duct cancer).[000236] In some embodiments, the dual binding antibody described herein, is used to treat any of the above listed cancers. In some embodiments, the cancer expresses Trop2. In some embodiments, the cancer expresses Nectin-4. In some embodiments, the cancer expresses Trop2 and Nectin-4. In some embodiments, the expression of Trop2 or Nectin-4, or both, at the tumor cell surface changes over time.[000237] In some embodiments, administration of a Tro p2 / N ectin-4 dual binding antibody, as part of an immune cell engager, leads to killing, slowing, or stopping the growth of cancer cells as part of a cancer patient’s therapeutic treatment.[000238] In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein, may be used for antibody-based treatments harnessing different mechanisms of action. In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be usedas part of an immune cell engager. In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be used as part of an Antibody Drug Conjugated (ADC). In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be used as a full IgG with Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) activity. In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be used as a full IgG with Complement Dependent Cytotoxicity (CDC) activity. In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be used as a full IgG with Antibody-Dependent Cellular Phagocytosis (ADCP) activity. In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be used as a radiolabeled antibody. In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be used as a cytokine-conjugated antibody. In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be used as part of an antibody- based delivery. In some embodiments, a Trop2 / Nectin-4 dual binding antibody described herein may be used as an antibody for the direct neutralization of the target proteinsTrop2 and Nectin-4.[000239] In some embodiments, disclosed herein is a method of treating a disease or a condition in a subject, comprising the step of administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof as disclosed herein, wherein said antibody targets a cancer cell. In some embodiments, disclosed herein is a method of treating a disease or a condition in a subject, comprising the step of administering to the subject a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof as disclosed herein, wherein said antibody targets a cancer cell.[000240] In some embodiments of a method of treating a disease ora condition in a subject, the method comprises a step of administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1, HCDR2, and HCDR3 and three light chain (CDRs) LCDR1, LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2 and HCDR3 comprise the amino acid sequences set forth in Tables 3A, 3B, or 3C and wherein the amino acid sequence of LCDR1, LCDR2 and LCDR3 comprise the amino acid sequences set forth in Tables 4A, 4B, or 4C, and wherein the amino acid sequences for HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 are all selected from the same clone variant. In some embodiments of a method of treating a disease or a condition in a subject, the method comprises a step of administering to thesubject s composition comprising:(a) a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1, HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2 and HCDR3 comprise the amino acid sequences set forth in Tables 3A, 3B, or 3C and wherein the amino acid sequence of LCDR1 , LCDR2 and LCDR3 comprise the amino acid sequences set forth in Tables 4A, 4B, or 4C, and wherein the amino acid sequences for HCDR1 , HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are all selected from the same clone variant; or(b) a polynucleotide encoding a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2 and HCDR3 comprise the amino acid sequences set forth in Tables 3A, 3B, or 3C and wherein the amino acid sequence of LCDR1, LCDR2 and LCDR3 comprise the amino acid sequences set forth in Tables 4A, 4B, or 4C, and wherein the amino acid sequences for HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 are all selected from the same clone variant.[000241] In some embodiments, a method of treating a subject suffering from a disease or condition comprises administering to the subject a composition comprising a Trop2 / Nectin- 4 dual binding antibody or dual binding fragment thereof, said antibody or fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1, HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 comprise:(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 814, SEQ ID NO: 815, SEQ ID NO: 816, SEQ ID NO: 817, SAS, and SEQ ID NO: 819, respectively;(c) SEQ ID NO: 820, SEQ ID NO: 821 , SEQ ID NO: 822, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(d) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(e) SEQ ID NO: 823, SEQ ID NO: 824, SEQ ID NO: 825, SEQ ID NO: 826, SAS, and SEQ ID NO: 828, respectively;(f) SEQ ID NO: 829, SEQ ID NO: 830, SEQ ID NO: 831 , SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(g) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively;(h) SEQ ID NO: 832; SEQ ID NO: 833; SEQ ID NO: 834, SEQ ID NO: 835, SAS, and SEQ ID NO: 837, respectively; or(i) SEQ ID NO: 838; SEQ ID NO: 839; SEQ ID NO: 840, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.[000242] In some embodiments, a method of treating a subject suffering from a disease or condition comprises administering to the subject a composition comprising- a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, said antibody or fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 comprise:(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 814, SEQ ID NO: 815, SEQ ID NO: 816, SEQ ID NO: 817, SAS, and SEQ ID NO: 819, respectively;(c) SEQ ID NO: 820, SEQ ID NO: 821 , SEQ ID NO: 822, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(d) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(e) SEQ ID NO: 823, SEQ ID NO: 824, SEQ ID NO: 825, SEQ ID NO: 826, SAS, and SEQ ID NO: 828, respectively;(f) SEQ ID NO: 829, SEQ ID NO: 830, SEQ ID NO: 831 , SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(g) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796,SEQ ID NO: 798, and SEQ ID NO: 800, respectively;(h) SEQ ID NO: 832; SEQ ID NO: 833; SEQ ID NO: 834, SEQ ID NO: 835, SAS, and SEQ ID NO: 837, respectively; or(i) SEQ ID NO: 838; SEQ ID NO: 839; SEQ ID NO: 840, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively; or- a polynucleotide encoding a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, said antibody or fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1, HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 comprise:0) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(k) SEQ ID NO: 814, SEQ ID NO: 815, SEQ ID NO: 816, SEQ ID NO: 817, SAS, and SEQ ID NO: 819, respectively;(l) SEQ ID NO: 820, SEQ ID NO: 821 , SEQ ID NO: 822, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(m)SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(n) SEQ ID NO: 823, SEQ ID NO: 824, SEQ ID NO: 825, SEQ ID NO: 826, SAS, and SEQ ID NO: 828, respectively;(o) SEQ ID NO: 829, SEQ ID NO: 830, SEQ ID NO: 831 , SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively;(p) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively;(q) SEQ ID NO: 832; SEQ ID NO: 833; SEQ ID NO: 834, SEQ ID NO: 835, SAS, and SEQ ID NO: 837, respectively; or(r) SEQ ID NO: 838; SEQ ID NO: 839; SEQ ID NO: 840, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.[000243] In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 of the antibodyor fragment thereof comprise SEQ ID NO: 791, SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively. In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 of the antibody or fragment thereof comprise SEQ ID NO: 814, SEQ ID NO: 815, SEQ ID NO: 816, SEQ ID NO: 817, SAS, and SEQ ID NO: 819, respectively. In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 of the antibody or fragment thereof comprise SEQ ID NO: 820, SEQ ID NO: 821, SEQ ID NO: 822, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801, respectively. In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a T rop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 of the antibody or fragment thereof comprise SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively. In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 of the antibody or fragment thereof comprise SEQ ID NO: 823, SEQ ID NO: 824, SEQ ID NO: 825, SEQ ID NO: 826, SAS, and SEQ ID NO: 828, respectively. In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 of the antibody or fragment thereof comprise SEQ ID NO: 829, SEQ ID NO: 830, SEQ ID NO: 831, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively. In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a compositioncomprising a T rop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 of the antibody or fragment thereof comprise SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively. In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 of the antibody or fragment thereof comprise SEQ ID NO: 832; SEQ ID NO: 833; SEQ ID NO: 834, SEQ ID NO: 835, SAS, and SEQ ID NO: 837, respectively. In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 of the antibody or fragment thereof comprise SEQ ID NO: 838; SEQ ID NO: 839; SEQ ID NO: 840, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.[000244] In some embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 of the antibody or fragment thereof comprise(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801, respectively;(b) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(c) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.[000245] In certain embodiments of a method of treating a subject suffering from a disease or condition, the method comprises administering to the subject(i) a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, said antibody or fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, andLCDR3, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 comprise:(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(c) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively; or(ii) a polynucleotide encoding a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the antibody or fragment thereof comprises three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, and LCDR3, and wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 comprise:(d) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(e) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(f) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.[000246] In some embodiments of a method of treating a disease ora condition in a subject, the method comprises a step of administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein the amino acid sequences of the VH and VL regions comprise the amino acid sequences set forth in Table 1 (SEQ ID NOs: 1-98, 786, 787) and Table 2 (SEQ ID NOs: 99-196, 788, 789), and wherein the amino acid sequences for VH and VL are selected from the same clone variant.[000247] In some embodiments of a method of treating a disease ora condition in a subject, the method comprises a step of administering to the subject a composition comprising a Trop2 / Nectin-4 dual binding antibody or a dual binding fragment thereof, said antibody or fragment thereof comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein the amino acid sequences of the VH and VL regions comprise (a) SEQ ID NOs: 787 and 789, respectively;(b) SEQ ID NOs: 20 and 118, respectively; or(c) SEQ ID NOs: 786 and 788, respectively.[000248] In some embodiments of a method of treating a disease or condition in a subject, the method comprises a step of administering to the subject a composition comprising a dual binding Trop2 / Nectin-4 antibodies or dual binding fragments thereof comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein the VH and VL sequences are at least 90% (e.g., at least 90%, 95%, 96%, 97%, 98%, or 99%) identical to the VH and VL sequences set forth above and as disclosed in Tables 1 and 2. One skilled in the art would appreciate that percent sequence identity may be determined using any of a number of publicly available software application, for example but not limited to BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters.[000249] In some embodiments of a method of treating a disease or condition in a subject, the method comprises a step of administering to the subject a dual binding Trop2 / N ectin-4 antibodies or dual binding fragments thereof comprising a heavy chain variable region (VH) and a light chain variable region (VL), wherein the amino acid sequences for the heavy chain variable region and the light chain variable region are set forth in any of the VH / VL sets presented for the antibodies of Tables 1 and 2, or comprise homologous sequences that are at least 90% (e.g., at least 90%, 95%, 96%, 97%, 98%, or 99%) identical to the VH and VL sequences set forth in Tables 1 and 2.[000250] A skilled artisan would appreciate that in some embodiments of a method of treating a subject suffering from a disease or condition, the method may comprise administering a Trop2 / Nectin-4 dual binding antibody or a Trop2 / Nectin-4 dual binding fragment thereof, or may comprise administering a polynucleotide encoding the Trop2 / Nectin-4 dual binding antibody or the Trop2 / Nectin-4 dual binding fragment thereof. The polynucleotide may encode a dual binding antibody or dual binding fragment thereof, based on CDR sequences, VH / VL sequences, or the HC and LC sequences. Methods of making and using the polynucleotide include those known in the art.[000251] In some embodiments, a method of treating a disease or a condition in a subject in need comprises administering a Trop2 / Nectin-4 dual binding antibody or a Trop2 / Nectin- 4 dual binding fragment thereof, or a composition comprising a Trop2 / Nectin-4 dual binding antibody or a Trop2 / Nectin-4 dual binding fragment thereof. In some embodiments, amethod of treating a disease or a condition in a subject in need comprises administering a polynucleotide encoding a Trop2 / Nectin-4 dual binding antibody, a Trop2 / Nectin-4 dual binding fragment thereof, or a composition of either the Trop2 / Nectin-4 dual binding antibody or the Tro p2 / N ectin-4 dual binding fragment thereof.[000252] In some embodiments of a method of treating a disease ora condition in a subject, the method comprises a step of administering to the subject a composition comprising any Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof as disclosed herein. [000253] In some embodiments of a method of treatment, a Trop2 / Nectin-4 dual binding antibody comprises an IgG, an Fv, an scFv, an Fab, an F(ab')2, a minibody, a diabody, a triabody, a DuoBody®, a multi-specific antibody, an immune cell engager, T cell engager, or a single domain antibody. In some embodiments of a method of treatment, a Trop2 / Nectin-4 dual binding antibody is in the form of an IgG, an Fv, an scFv, an Fab, a F(ab')2, a minibody, a diabody, a triabody, an immune-cell engager, a multi-specific antibody, or a multi-engager.[000254] In some embodiments, an IgG can be of the subclass of lgG1 , lgG2, lgG3, or lgG4.[000255] In some embodiments a method comprises administering a composition comprising a Trop2 / Nectin-4 dual binding antibody or Trop2 / N ectin-4 dual binding fragment thereof. In some embodiments a method comprises administering a Trop2 / Nectin-4 dual binding antibody or Trop2 / Nectin-4 dual binding fragment thereof.[000256] In some embodiments, treatment of cancer comprises maintenance treatments. In some embodiments, maintenance treatments are administered to maintain the absence of a cancer or tumor. In some embodiments, maintenance treatments are administered to maintain lack of metastasis of a cancer or tumor. In some embodiments, maintenance treatments are administered to inhibit metastasis of a cancer or tumor. In some embodiments, maintenance treatments are administered to maintain lack of growth of a cancer or tumor. In some embodiments, maintenance treatments are administered to inhibit growth of a cancer or tumor. In some embodiments, treatment of cancer reduces the size of a tumor. In some embodiments, treatment of a cancer reduces the proliferation of the cancer.[000257] In some embodiments, a polynucleotide sequence encoding an engineered Trop2 / Nectin-4 dual binding antibody is used in a method of treating a subject with a diseaseor condition as described herein, wherein the polynucleotide encodes a Trop2 / Nectin-4 antibody comprising a heavy chain variable region and a light chain variable region as set forth in Tables 1 and 2, respectively.[000258] As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.[000259] Throughout this application, various embodiments may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the antibodies disclosed herein. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.[000260] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging / ranges between” a first indicate number and a second indicate number and “ranging / ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals there between.[000261] A skilled artisan would appreciate that the term “about’, may encompass a deviance of between 0.0001-5% from the indicated number or range of numbers. In some instances, the term “about”, may encompass a deviance of between 1 -10% from the indicated number or range of numbers. In some instances, the term “about’, encompasses a deviance of up to 25% from the indicated number or range of numbers.EXAMPLESExample 1: Production Trop2 / Nectin-4 Antibody and Binding Analysis[000262] Objective’. To generate unique, dual binding antibodies.[000263] Methods:[000264] Methods of Library Design[000265] Leveraging artificial intelligence (Al) technology, a library was designed for dual specific human Trop2 (hTrop2) and human Nectin4 (hNectin4) antibodies. Following screening and selection of the library to bind both hTrop2 and hNectin4, and affinity maturation campaigns, 100 unique Heavy chain (VH) - Light chain (VL) pair variable regions were identified, wherein the amino acid sequences of the Heavy chain and Light chain variable region pairs are presented in Tables 1 and 2 below.[000266] Method of Library Construction[000267] Single-chain variable fragment (ScFv) Libraries were constructed by overlapping extension PCR with degenerate oligonucleotides. PCR to introduce diversity was done using Phusion high fidelity DNA polymerase (New England Biolabs USA, Cat: M0530) according to manufacturer instructions in a 3-step reaction (98°C for 30 sec, 65°C for 20 sec, 72°C for 30 sec, 30 cycles). The PCR products were gel purified by gel purification kit and assembled (100ng from each) in equimolar ratios in a 3-step PCR reaction, as above, in the absence of primers. The assembled PCR product was reused as the template for PCR amplifying the full scFv library, as above, using forward and reverse primers adding vector sequences 5’ and 3’ to the scFv library to efficiently perform homologous recombination in yeast cells.[000268] Library transformation was conducted as published (Benatuil et al., (2010) An improved yeast transformation method for the generation of very large human antibody libraries. Protein Eng. Des. Sei. 23, 155-159). 400pl of a yeast suspension (EBY100, ATCC, USA) per 0.2cm cuvette (cell projects) was electroporated (BioRad, USA, GenePulser) with 4pg linearized vector (pCTcon3) and 12pg DNA insert (scFv Library) in a 1:3 vector to insert ratio (Chao, G. et al. Isolating and engineering human antibodies using yeast surface display. Nat. Protoc. 1 , 755-768 (2006)). The number of transformants of each library was determined to -1-5X109by serial dilutions of transformed cells (Benatuil et al. (2010) ibid) [000269] Methods of Screening and Selection using Yeast Surface display[000270] Yeast-displayed scFv libraries were grown in a SDCAA selective medium and induced for expression with 2% w / v galactose at 20 °C for 48 hours according to established protocols (Chao et al., (2006) ibid) The library was screened on BioRad S3e Fluorescence Activated Cell Sorter for high affinity binders of hTrop2 (Acrobiosystems, China) usingmouse anti-Myc-FITC (Santa Cruze, USA) and goat anti human Fc-APC (Jackson Immuno research, USA). Isolated clones from the final sort were sequenced by extraction of plasmid DNA from the yeast clones using a Zymoprep kit (Zymo Research, USA) and the DNA was sequenced. The chosen clones were incubated with either 1 nM recombinant human Trop2 (hTrop2)-His or 1nM recombinant human Nectin4 (hNectin4)-His for 1 hour at room temperature. Cells were washed and resuspended in ice-cold PBS 0.1 % BSA buffer containing a fluorescent labeled secondary antibody as described above for 20 min and analyzed using a flow cytometer. The values obtained were normalized to expression levels and to a positive control (an anti-Trop2 or anti-Nectin4 binding antibody; positive control antibodies comprising binding regions of Sacituzumab and Enfortumab, respectively).[000271] Sacituzumab and Enfortumab usedin the Examples[000272] For clarification, in the experiments below when Sacituzumab and Enfortumab were used, the naked antibody was used, i.e. , without the linker and drug payload. The Sacituzumab antibody portion is named hRS7 and the Enfortumab antibody is named AGS- 22.[000273] Sequences used for Sacituzumab: Sacituzumab Trop2 variable domain: VH: Sequence 14 from patent US 9999668 and VL: Sequence 12 from patent US 9999668. US 9999668 is incorporated herein in full.[000274] Sequences used for Enfortumab: Enfortumab Nectin4 variable domain: VH: taken from Sequence 7 from patent US 10894090 and VL: taken from Sequence 8 from patent US 10894090. US 10894090 is incorporated herein in full.[000275] Method of specificity assessment in yeast[000276] The selected clones were incubated with either 300nM recombinant human TROPI-Fc or 500nM of NECTIN1-His, NECTIN2-His and NECTIN3-His mix for 1 hour at room temperature. Cells were washed and resuspended in ice-cold PBS 0.1% BSA buffer containing a fluorescent labeled secondary antibody as described above for 20 min and analyzed using a flow cytometer. The values obtained were normalized to expression levels. [000277] Method of EC-50 in yeast[000278] The selected clones were incubated with a range of dilutions of 0-100nM recombinant human Trop2 (hTrop2)-His or a range of dilutions of 0-1000nM recombinant human Nectin4 (hNectin4)-His for 1 hour at room temperature. Cells were washed and resuspended in ice-cold PBS 0.1 % BSA buffer containing a fluorescent labeled secondaryantibody as described above for 20 min and analyzed using a flow cytometer. The values obtained were normalized to expression levels.[000279] Methods of determining EC50 binding by representative lgG1 formatted clones to human Trop2 (hTrop2) and human Nectin-4 (hNectin-4) by ELISA[000280] Multiwell plates (Thermo Scientific, 464718) were coated with 100ng / well Antibody I gG 1 clones (Abs), then washed and blocked with 3% skim milk in PBS with 0.05% Tween®. Post blocking, hT rop2-His tag or hNectin4-His tag was added to the wells in a concentration range of 0nM-100nM and incubated for 1 hour at room temperature (RT). The plates were washed and binding of either hTrop2-His tagged or hNectin4-His tagged to the dual Abs was detected using HRP-conjugated-anti-6x His antibody (Abeam, ab1187), was added. The reaction was developed and stopped using TMB (Southern-Biotech cat:0410-01) and stop solution (Southern-Biotech cat:0412-01) respectively and read at 450nm. As used throughout the Examples, the terms “IgG”, “lgG1”, “hlgG1” and “human lgG1”, and the like, may be used interchangeably having all the same meanings and qualities.[000281] Method of IgG production[000282] All the sequences that were identified in the selection stage of the Yeast-displayed scFv libraries, were produced using GeneScript antibody production services (Genscript NJ, USA), as human I gG1 with or without a silent Fc (LAU\ mutation); L234 and L235 of the heavy chain was mutated to alanine codons (L234A, L235A). The heavy chain contains a single point mutation in preparation to assembling it as part of a multispecific antibody, as previously described (Labrijn, A. F. et al. “Efficient generation of stable bispecific lgG1 by controlled Fab-arm exchange.” Proc. Natl. Acad. Sci. U. S. A. 110, 5145-5150 (2013)), wherein K409 of the heavy chain was mutated to arginine (R).[000283] Methods of Surface Plasmon Resonance (SPR) analysis[000284] Measurements of hlgG1 antibodies binding to human or cynomolgus monkey Trop2: The SPR analysis was done on Biacore S200 (Cytiva) on S CM5 (BR1000530, Cytiva) chip. The S CM5 chip was crosslinked with primary human antibody capture kit (29234600, Cytiva) to a target of 5000RU, after cross linking of the primary antibody, the tested antibodies were immobilized on the primary antibody to a target of 100RU. The hTrop2 (Aero) or cynoTrop2 (Aero) analyte was injected in PBS-T buffer at concentrations ranging from 400nM to 0.5nM in a series of two-fold dilutions, one concentration for each cycle. Subsequent to a cycle, the analyte and tested antibody were stripped from the chipand new tested antibody was loaded on the chip as described above. Kinetics and affinities were determined using 1: 1 binding model.[000285] Measurements of hlgG1 antibodies binding to human or cynomolgus monkey Nectin4: The SPR analysis was done on Biacore S200 (GE) on Protein A (29127555, Cytiva). The tested antibodies were immobilized on the primary antibody to a target of 100- 150RLI. The hNectin-4 (Aero) analyte was streamed in PBS-T pH 7.4 buffer at concentrations ranging from 600nM to 1.1nM in a series of two-fold dilutions, one concentration for each cycle. Subsequent to a cycle, the analyte and tested antibody were stripped from the chip and new tested antibody was loaded on the chip as described above. Kinetics and affinities were determined using 1:1 binding model.[000286] Method of ELISA binding to human paralogues TROP1, Nectin-1, Nectin-2, and Nectin-3[000287] ELISA plates (Greiner Bio-One Cat:655081) were coated with 50 ng / well of either recombinant human Tropl (EpCAM), human Nectin-1, human Nectin-2, or human Nectin-3 antigens then washed and blocked with 3% skim milk in PBS with 0.05% tween. Postblocking the tested antibodies were added to the wells at a concentration of 1000 nM and incubated for 1 hour at room temperature. The plates were washed and HRP-conjugated- goat anti-Flag secondary antibody (Jackson cat: 109-035-008) was added to detect bound antibody. The reaction was developed using TMB (Southern-Biotech cat:0410-01) and stop solution (Southern-Biotech cat:0412-01) and read at 450 nm on a spectrophotometer. Positive control antibodies that were used as controls for the tested antigens are: monoclonal anti Nectin-1 antibody (CK8) (Invitrogen Cat: 37-5900), anti-human Nectin-2 (CD112) (Biolegend Cat: 337410), anti-Nectin-3 / PVRL3 (CD113) (EMD Milipore), and monoclonal anti EpCAM (ALIA1) (Invitrogen Cat: MA1-46104).[000288] Method of BiTE® production[000289] Sequences that were identified in the selection stage of the Yeast-displayed scFv libraries, were produced as muti-specific antibodies using GeneScript antibody production services (Genscript NJ, USA). The multi-specific antibodies were produced as BiTE®, designed to target CD3 and tumor-specific antigens (Trop2 and or Nectin-4) simultaneously and promote the cytotoxicity of T cells. Each BiTE® consists of two single-chain variable fragments (scFvs) connected by a flexible linker and a FLAG tag (SEQ ID NO: 785) at the C-terminal end of the protein. The scFvs of the TAA arm were derived from sequences thatwere identified in the selection stage of the Yeast-displayed Trop2 / Nectin-4 dual binding scFv libraries described above, and the scFv of the immune arm was derived from the commercially available anti-CD3 pacanalotamab (Pacanalotamab anti-CD3 binding variable domain: VH and VL: Sequence 340 from US 10766969).[000290] Methods of determination of BiTE EC50 binding to human Trop2 and human Nectin-4 by ELISA[000291] Plates (Greiner Bio-One Cat:655081) were coated with 50ng / well hTrop2 or hNectin-4 antigen, then washed and blocked with 1.5% BSA in PBS with 0.05% tween. Post blocking the tested BiTE® was added to the wells in a concentration range of 0nM-30nM and incubated for 1 hour at room temperature (RT). The plates were washed and HRP- conjugated-goat anti-Flag secondary antibody (Jackson cat: 109-035-008), was added. The reaction was developed and stopped using TMB (Southern- Biotech cat:0410-01) and stop solution (Southern- Biotech cat:0412-01) respectively and read at 450nm.[000292] Methods of reporter assay Trop2 / nectin4 NFAT lucia - BiTE®[000293] Jurkat-LuciaTM NFAT effector cells were used to evaluate T cell activation by the Trop2 / Nectin-4xCD3 BiTE® in the presence of HEK293-Trop2 (acrobiosystems; CHEK- ATP036), HEK293-Nectin-4 (acrobiosystems; CHEK-ATP035). The target cells were seeded at 40,000 cells / well in a 96-well plate in 100pl of DM EM complete media and incubated at 37°C overnight in 5% CO2 incubator. The next day, BiTE®s were serially diluted in RPMI L-Glu medium supplemented with 10% FBS and 2mM HEPES. 120,000 cells / well Jurkat-LuciaTM NFAT effector cells were added to the target cell and incubated at 37°C in 5% CO2 incubator (E:T 3:1 ratios). After 24h, co-culture supernatant was mixed with the Quanti-Luc™ 4 Reagent (InvivoGen, #rep-qlc4lg1). The luminescence signal was measured on the Synergy LX multi-mode plate reader (BioTek). Analysis was performed using either Prism (GraphPad) or Excel (Microsoft).[000294] Methods of PBMCs killing assay- BiTE®[000295] Peripheral blood mononuclear cells (PBMCs; Cell Generation, Israel) were used to evaluate the cytotoxic effects mediated by BiTE®s in the presence of HEK293-Trop2 and HEK293-Nectin-4 target cells. The target cells were seeded at 30,000 cells / well in a 96-well plate in 100pl of DM EM complete media and incubated at 37°C overnight in 5% CO2 incubator. The next day, BiTE®s were prepared in RPMI 1640 medium supplemented with 10% FBS, 2mM HEPES, 1 % GlutaMAX supplement, 1 % Sodium-pyruvate and 1% non-essential AA, added to the wells containing the target cells. Subsequently, PBMCs were added to each well at E:T ratio of 10:1 (300,000 cells / well). Following 48h, supernatants were collected, and Cytotoxicity Detection Kit (LDH) (Roche, #11-644-793-001) was used to determine the level of cytotoxicity according to the manufacturer’s protocol. T cell activation was validated using Human IFN-y ELISA Kit (Invitrogen, #88-7316) according to the manufacturer’s protocol. T o analyze the results, the sample were read using the Synergy LX multi-mode plate reader (BioTek). The percentage of cell-mediated cytotoxicity was determined by the following formula: [((Effector cell+ Target cell mix- Effector cells ctrl)- Target cell control)) / (Max LDH control- Target cell ctrl)]*100). The maximum LDH release was from wells with target cells lysed using 2% Triton X-100. Analysis was performed using either Prism (GraphPad) or Excel (Microsoft).[000296] Method of Duo Body® production[000297] Sequences that were identified in the selection stage of the Yeast-displayed Trop2 / Nectin-4 scFv libraries, were produced as IgG-like antibodies using GeneScript antibody production services (Genscript NJ, USA). The IgG-like antibodies were produced as multispecific antibodies or multi-engagers in the controlled Fab-arm exchange (cFAE) method as described in Labrijn, A. F .et al. 2013. Tested antibodies were produced as an IgG like T-cells engager in a DuoBody® format. The Duobody® format consists of two arms, where one arm comprises the variable domain of a published anti-CD3 antibody derived from an approved T-cell engager (pacanalotamab) and the second arm comprises of the variable domains (VH and VL) of the antibodies listed in Table 1 and Table 2, respectively. Antibodies were produced as human I gG 1 with silent Fc (U\LA mutation; L234 and L235 of the heavy chain was mutated to alanine codons (L234A, L235A)).[000298] Methods of determination of DuoBody® EC-50 binding to human Trop2 and human Nectin-4 by ELISA[000299] Plates (Greiner Bio-One Cat:655081) were coated with 50ng / well hTrop2 or hNectin-4 antigen, then washed and blocked with 1.5% BSA in PBS with 0.05% tween. Post blocking the tested Duobodies as added to the wells in a concentration range of 0nM-30nM and incubated for 1 hour at room temperature (RT). The plates were washed and HRP- conjugated-goat anti- human Fc secondary antibody (Jackson cat: 109-035-008), was added. The reaction was developed and stopped using TMB (Southern-Biotech cat:0410- 01) and stop solution (Southern- Biotech cat:0412-01) respectively and read at 450nm.[000300] Methods of reporter assay Trop2 / Nectin4 NFAT lucia - DuoBod ^[000301] Jurkat-Lucia™ NFAT effector cells were used to evaluate T cell activation by the DuoBody® tested IgG like T-cell engager-Duobodies, in the presence of HEK293-Trop2 (acrobiosystems; CHEK-ATP036), HEK293-Nectin-4 (acrobiosystems; CHEK-ATP035) or MCF7 target cells (ATCC; HTB-22 ™). The target cells were seeded at 40,000 cells / well in a 96-well plate in 10OpI of DM EM complete media and incubated at 37°C overnight in 5% CO2 incubator. The next day, Duobodies were serially diluted in RPMI L-Glu medium supplemented with 10% FBS and 2mM HEPES. 120,000 cells / well Jurkat-Lucia™ NFAT effector cells were added to the target cell and incubated at 37°C in 5% CO2 incubator (E:T 3:1 ratios). After 24h and 48h (only for MCF7 cells), co-culture supernatant was mixed with the Quanti-Luc™ 4 Reagent (InvivoGen, #rep-qlc4lg1). The luminescence signal was measured on the Synergy LX multi-mode plate reader (BioTek). Analysis was performed using either Prism (GraphPad) or Excel (Microsoft).[000302] Methods of PBMCs killing assay- DuoBody®[000303] Peripheral blood mononuclear cells (PBMCs; Cell Generation, Israel) were used to evaluate the cytotoxic effects mediated by Duobodies in the presence of HEK293-Trop2 and HEK293-Nectin-4 target cells. The target cells were seeded at 30,000 cells / well in a 96- well plate in 100pl of DM EM complete media and incubated at 37°C overnight in 5% CO2 incubator. The next day, Duobodies were prepared in RPMI 1640 medium supplemented with 10% FBS, 2mM HEPES, 1% GlutaMAX supplement, 1 % Sodium-pyruvate and 1 % non-essential AA, added to the wells containing the target cells. Subsequently, PBMCs were added to each well at E:T ratio of 10:1 (300,000 cells / well). Following 48h, supernatants were collected, and Cytotoxicity Detection Kit (LDH) (Roche, #11-644-793-001) was used to determine the level of cytotoxicity according to the manufacturer’s protocol. T cell activation was validated using Human IFN-y ELISA Kit (Invitrogen, #88-7316) according to the manufacturer’s protocol.[000304] To analyze the results, the samples were read using the Synergy LX multi-mode plate reader (BioTek). The percentage of cell-mediated cytotoxicity was determined by the following formula: [((Effector cell+ Target cell mix- Effector cells ctrl)-Target cell control)) / (Max LDH control- Target cell ctrl)]*100. The maximum LDH release was from wells with target cells lysed using 2% Triton X-100. Analysis was performed using either Prism (GraphPad) or Excel (Microsoft).[000305] Table 8 tabulates the antibody binding regions and immunoglobulin structures used in the Examples.[000306] Table 8: Antibody Constructs[000307] Results:[000308] Screening And Selection of Dual Binding Antibodies[000309] Objective: Screen engineered dual binding antibodies to identify those with the highest and selective binding for Trop2 and Nectin-4.[000310] Results: Following screening and selection of the libraries to bind both Trop2 and Nectin-4, in the final round of selection an enriched population of yeast-displayed clones was identified.[000311] One Hundred (100) unique Heavy chain (VH) - Light chain (VL) pair variable regions were identified, wherein the amino acid sequences of the Heavy chain and Light chain variable region pairs are presented in Tables 1 and 2 below. Table 1 provides the amino acid sequences of the VH region for each clone and Table 2 provides the amino acid sequence of the VL region for each clone, wherein the VH and VL from the same clone are paired to form the scFv. [000312] As used herein, in some embodiments the term “variant’ and “clone” are used interchangeably having all the same meanings and qualities.[000313] Table 1 : Amino acid sequences of engineered Trop2 / Nectin-4 dual binding antibody Variable Heavy chain regions (VH).[000314] Table 2: Amino acid sequences of engineered Trop2 / Nectin-4 dual binding antibody Variable Light chain regions (VL).[000315] Representative scFv amino acid sequences are provided here for CID clone variants CID2822:DIQLTQSPSSLSASVGDRVSITCKASQDVSIAVAWYQQKPGKAPKLLIYSASYRNYGVPD RFSGSGSGTDFTLTISSLQPEDFAVYYCQQHYITPLTFGAGTKVEIKGGGGSGGGGSGGGGSQVQLQQSGSELKKPGASVKVSCKASDYTFKNYGMNWVKQAPGQGLKWMGKINL VTGETTYTDDFKGRFAFSLDTSVSTAYLQISSLKADDTAVYFCARGGFGSSYWYFDNW GQGSLVTVSS (VL-linker-VH; SEQ ID NO: 811); CID2040:DIQLTQSPSSLSASVGDRVSITCKASQDVSIAVAWYQQKPGKAPKLLIYSASYRNYGVPDRFSGSGSGTDFTLTISSLQPEDFAVYYCQQHYITPLTFGAGTKVEIKGGGGSGGGGSGG GGSQVQLQQSGSELKKPGASVKVSCKASDYTFKNYGMNWVKQAPGQGLKWMGKINT YTGKTYYTDDFKGRFAFSLDTSVSTAYLQISSLKADDTAVYFCARGGFGSSYWYFDNW GQGSLVTVSS (VL- linker- VH; SEQ ID NO: 812); and CID2821: DIQLTQSPSSLSASVGDRVSITCKASQDVSIAVAWYQQKPGKAPKLLIYSASYRYYGVPD RFSGSGSGTDFTLTISSLQPEDFAVYYCQQHYITPLTFGAGTKVEIKGGGGSGGGGSGG GGSQVQLQQSGSELKKPGASVKVSCKASDYTFKNYAMNWVKQAPGQGLKWMGRINTI TGEVTYTDDFKGRFAFSLDTSVSTAYLQISSLKADDTAVYFCARGGFGSSYWYFDGWG QGSLVTVSS (VL-linker-VH; SEQ ID NO: 813).[000316] The amino acid sequences of each VH and VL were next analyzed to determine the heavy chain and light chain CDR regions for each clone (HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, LCDR3, respectively). The amino acid sequences for the heavy and light chain CDRs are listed according to the Chothia numbering scheme in Table 3A (Heavy chain CDRs) and Table 4A (Light chain CDRs), which is based on analysis of canonical structures in antibodies (Chothia, C. & Lesk, A. M. Canonical structures for the hypervariable regions of immunoglobulins. J. Mol. Biol. 196, 901-917 (1987); Al-Lazikani, B., Lesk, A. M. & Chothia, C. Standard conformations for the canonical structures of immunoglobulins. J. Mol. Biol. 273, 927-948 (1997); Chothia, C. et al. Conformations of immunoglobulin hypervariable regions. Nature 342, 877-883 (1989)). The amino acid sequences for the heavy and light chain CDRs for representative clones are listed according to the IMGT numbering scheme in Table 3B (Heavy chain CDRs) and Table 4B (Light chain CDRs). The amino acid sequences for the heavy and light chain CDRs for representative clones are listed according to the Kabat numbering scheme in Table 3C (Heavy chain CDRs) and Table 4C (Light chain CDRs).[000317] Table 3A: Amino Acid Sequences of Heavy-chain CDR Regions for Antibody Clones[000318] Table 3B: Amino Acid Sequences of Heavy-chain CDR Regions for Representative Antibody Clones, as determined by IMGT[000319] Table 3C: Amino Acid Sequences of Heavy-chain CDR Regions for AntibodyClones, as determined by Kabat[000320] Table 4A: Amino Acid Sequences of Light-chain CDR Regions for Antibody Clone[000266] Table 4B: Amino Acid Sequences of Light-chain CDR Regions for Antibody Clone according to IMGT[000321] Table 4C: Amino Acid Sequences of Light-chain CDR Regions for AntibodyClone according to Kabat[000322] The dual binding antibody clones used include those in a human lgG1 format and those in a human lgG1 format with a modified Fc region. Table 5 below provides a guide for the format of representative dual binding antibody clones.[000323] Table 5A. Representative Dual Binding Antibodies & Formats Thereof.[000324] Table 5B. Heavy Chain (HC) and Light Chain (LC) Amino Acid Sequences of Representative Dual Binding Antibodies.[000325] The population of 98 unique Heavy chain (VH) - Light chain (VL) pair variable regions bind to Trop2 at 1 nM and Nectin-4 at 1 nM. (Fig. 2A and Fig. 2B, respectively). In parallel to the evaluation of the yeast-displayed libraries, an anti-Trop2 antibody (Sacituzumab) and an anti-Nectin-4 antibody (Enfortumab) were evaluated for binding their respective antigens as control (Fig. 3A and Fig. 3B, respectively). Sacituzumab demonstrated binding only to Trop2 and Enfortumab demonstrated binding only to Nectin- 4.[000326] The Trop2 and Nectin-4 EC50 values and the results of analysis for off-target binding are presented in Table 6.[000327] Table 6: Binding properties of 98 clone variants (scFv) measured usingyeast display methodology.**was not checked-collected from the same gate as tested variants.## Evaluated as a pool of all population.*Clear indicates that no binding was detected.[000328] Clones CID2821 and CID282 also demonstrated specific binding to Trop2 and Nectin-4 with no off-target non-specific binding similarly to the 98 tested clones shown in Table 6.[000329] Following screening and selection of the libraries to bind both Trop2 and Nectin- 4, binding EC-50 of single clones isolated from the enriched population of Trop2 / Nectin-4 dual binders was evaluated. Eleven (11) Yeast-displayed dual binders (clone variants: CID1892, CID1896, CID1891 , CID1893, CID1895, CID1889, CID1898, CID1897, CID1899,CID1900, and CID1452) were incubated with a range of dilutions of 0-100nM hTrop2-His to determine their apparent affinity in a flow-cytometry based binding assay (Fig. 4A). All clones demonstrated binding to Trop2 with an EC-50< 6.5nM (Table 7).[000330] These same clones were evaluated for their apparent EC-50 for Nectin-4-His in a range of dilutions of 0-1000nM hNectin-4-His (Fig. 4B). All clones demonstrated binding to Nectin-4 with an EC- 50 < 6.6nM (Table 7).[000331] Table 7: Representative Clone Variants (scFv) EC-50 binding parametersClear indicates that no binding was detected.[000332] The dual-binding clones that emerged from yeast display selections were evaluated for specificity over closely related paralogs. Trop2 is a paralog of epithelial- specific cell adhesion molecule Tropl (EpCAM), and Nectin-4 has three related paralogs (Nectinl , Nectin2 and Nectin3). All clones were shown to bind specifically to Trop2 andNectin-4, but not to any of their paralogues. Variant CID1895 lacking binding to Tropl and Nectin1-3 is presented as a representative clone in Figs. 5A and 5B, respectively.[000333] A summary of the analysis of 11 yeast-displayed dual binders dual binders (CID1892, CID1896, CID1891, CID1893, CID1895, CID1889, CID1898, CID1897, CID1899, CID1900, CID1452) is detailed in Table 7 above (Data for other clones is not shown).[000334] Biochemical Characterization of dual antibodies as full IgGs[000335] Objective’. To reformat the selected clones to a human lgG1 format (hlgG1) and analyze the hlgG1 antibodies for dual Trop2 and Nectin-4 binding. [000336] Results: Subsequent to characterization in the yeast surface display format, variants CID1895 and CID2822 were produced as human lgG1s with a silent Fc (LAU\ mutations as described above; See Table 5). The affinity of variants CID1895 and CID2822to human Trop2 and Nectin-4, and their cynomolgus orthologs was tested. The sequence identity between the extracellular domain of human Trop2 (Uniprot entry P09758) and its ortholog in Macaca fascicularis (Cynomolgus; “cyno”) is 98.4%. The sequence identity between the extracellular domain of human Nectin-4 and its ortholog in in Macaca fascicularis is 99.4%.[000337] Surface plasmon resonance (SPR) analysis was performed to calculate the kinetics of binding for variant CID1895 (Fig. 6A against human Trop2 and Fig. 6B against cyno Trop2; Fig. 6E against human Nectin-4 and Fig. 6F against cyno Nectin-4), anti-Trop2 Sacituzumab (Fig. 6C against human Trop2 and Fig. 6D against cyno Trop2) and anti- Nectin-4 benchmark Enfortumab (Fig. 6G against human Nectin-4 and Fig. 6H against cyno Nectin-4) in lgG1 formats, and for variant CID2822 (BDG2.182) in hlgG1 format (Fig. 6I against human Trop2 and Fig. 6J against cyno Trop2; Fig. 6K against human Nectin-4 and Fig. 6L against cyno Nectin-4), using Biacore S200. Antibodies were captured on either Protein A chip or S CM5 chip coated with anti-human capture antibody, to reach 100-200 Rll. Human / cyno Trop2 and Nectin-4 were used as analytes and injected in concentration range of 600-0.5 nM in multi-cycle strategy.[000338] Variant CID1895 presents a KD of 0.8nM to human Trop2 (Fig. 6A) and a KD of 0.25 nM to cyno Trop2 (Fig. 6B) and presents a KD of 22.4 nM to human Nectin-4 (Fig, 6E) and a KD of 19.8 nM to cyno Nectin-4 (Fig. 6F). Variant CID2822 has a KD of 3.1 nM to human Trop2 (Fig. 6I) and 1.8 nM to cyno Trop2 (Fig 6J) and a KD of 17.9 nM to human Nectin-4 (Fig. 6K) and 14.2 nM to cyno Nectin-4 (Fig. 6L). Similar results were observed for other dual binding antibody clones produced as IgG (Data not shown). Sacituzumab presents KD of 0.388 nM to human Trop2 (Fig. 6C) and 0.34 nM to cyno Trop2 (Fig. 6D). Enfortumab presents KD of 5.5 nM to human Nectin-4 (Fig. 6G) and 6 nM to cyno Nectin-4 (Fig. 6H).[000339] ELISA binding was performed to determine the binding of BDG2.121 (CID2040 in the hlgG1 LALA format), BDG2.184 (CID2821 in hlgG1 format), BDG2.182 (CID2822 in the hlgG1 format) to recombinant human Trop2 paralogue epithelial-specific cell adhesion molecule / Trop1 (EpCAM), and human Nectin-4 related paralogs Nectin-1 , Nectin-2 and Nectin-3.[000340] Results showed that CID2040 (BDG2.121), CID2821 (BDG2.184), and CID2822 (BDG2.182) all of which had been shown to bind to human Trop2 and human Nectin-4) didnot bind to human TR0P1 (EpCAM) or human Nectin-1, Nectin-2 or Nectin-3 when applied to ELISA plates at 1000 nM concentration although control antibodies (monoclonal anti Nectin-1 antibody (CK8), anti-human Nectin-2 (CD112), anti-Nectin-3 / PVRL3 (CD113), and monoclonal anti EpCAM (ALIA1)) did bind to these proteins under these conditions (Fig. 6M). This demonstrates that the binding of CID2040, CID2821 and CID2822 have specificity for Trop2 and Nectin-4 and do not bind non-specifically to other proteins in the same family. [000341 ] Biochemical Characterization of dual antibodies as multi-specific antibodies in BiTE® format[000342] Objective’. To reformat the selected clones as a multi-specific antibody in a BiTE® format (e.g., multi-engager), coupled to an anti-CD3 arm. Analyze the BiTE® molecules for dual Trop2 and Nectin-4 binding.[000343] Results: In order to demonstrate the potential of our sequences as immune engagers, multi-specific antibodies were constructed comprising two arms: one arm consists of a commercially available anti-CD3 binder, and the other arm consists of our dual binders of Trop2 / Nectin-4.[000344] Variant CID 1895 was constructed as a multi-specific antibody in a BiTE® format. A BiTE® molecule consists of two scFvs connected by a short peptide linker. One scFv is derived from an anti-CD3 binder (pacanalotamab; Pacanalotamab anti-CD3 binding variable domain: VH and VL: Sequence 340 from US 10766969), and the other is derived from variant CID 1895. The BiTE®s were produced with a FLAG tag at the c-terminal end of the protein for purification and detection.[000345] ELISA EC-50 analysis was performed to evaluate the dual binding of BiTE® BDB2.004 (CID1895 x CD3) to Trop2 and Nectin-4 and compared to the binding of Sacituzumab and Enfortumab in BiTE® formats (Figs. 7A - 7C). BDD2.004 binds human Trop2 with an EC- 50 of 0.9nM and Nectin-4 with an EC-50 of 1.12nM, as measured by ELISA. BDD2.010 (Sacituzumab x CD3 in BiTE® format) binds Trop2 with an EC-50 of 1.39nM. BDD2.017 (Enfortumab x CD3 in BiTE® format) binds Nectin-4 with an EC-50 of 0.48nM.[000346] Cell-based assay to demonstrate the functional activity of Trop2 / Nectin-4 dual binders as immune engagers in BiTE format[000347] Objective’. To evaluate T cell activation and cytotoxicity effect mediated by the BiTE molecules in a co-culture of T cells and TAA expressing cell lines.[000348] Results: Jurkat-Lucia™ NFAT effector cells were used to evaluate T cell activation by the Trop2 / Nectin-4xCD3 BiTE® in co-culture with HEK293-Trop2 or HEK293-Nectin-4. BDB2.004 (variant CID 1895 x CD3 in BiTE® format) mediated engagement and activation of Jurkat-Lucia™ reporter T-cell line in co-culture of both HEK293-Trop2 (Fig. 8A) and HEK293-Nectin-4 (Fig. 8B) in a dose-dependent manner, with an EC- 50 of 0.28nM over HEK293-Trop2 and EC- 50 of 0.19nM over HEK293-Nectin-4. BDB2.010 (Sacituzumab x CD3 in BiTE® format) mediated activation of the reporter cells only when co-cultured with HEK293-Trop2 cells. BDB2.004 and BDB2.010 showed similar E-max levels (-120,000 RLU), indicating that CID1895 mediated a similar level of T cell activation to Sacituzumab. BDB100.006 (non-binding-control xCD3 in BiTE® format) was used as negative control, and did not demonstrate activation of T cells in any of the co-culture assays.[000349] Peripheral blood mononuclear cells (PBMCs) were used to evaluate the immune cells cytotoxicity effects mediated by BiTE®s in co-culture with HEK293-Trop2 and HEK293- Nectin-4 target cells. The tested BiTE® molecules, comprised of one arm targeting CD3 and the other targeting Trop2 / Nectin-4, are evaluated for their ability to engage the T cell population present in PBMCs and promote their cytotoxic effect on the target cells. Viability of the target cells is measured by LDH, an intracellular enzyme which is released to the supernatant upon cell death, and T cell activation is validated by measuring the levels of Interferon-gamma (IFN-y) in the supernatant. BDB2.004 (variant CID 1895 x CD3 in BiTE® format) led to target cell death in a dose-dependent manner, when PBMCs were co-cultured with both HEK293-Trop2 (Fig. 9A) and HEK293-Nectin-4 (Fig. 9B) target cells. BDB100.006 (non-binding-control xCD3 in BiTE® format) was used as negative control, and did not demonstrate activation of T cells in any of the co-culture assays. The high IFN-y measured in the supernatants (Figs. 10A-10B) following incubation with BDB2.004 demonstrate additional validation for T cell activation. The lack of IFN-y release following incubation with the negative control BDB100.006 provides additional evidence that the observed killing facilitated by BDB2.004 is specifically due to the engagement and interaction between the T cells and the target cells, and not by non-specific T cell activation. [000350] Biochemical Characterization of dual antibodies as multi-specific antibodies in DuoBody® format[000351] Objective’. To reformat the selected clones as a multi-specific antibody in a DuoBody® format, coupled to an anti-CD3 arm. Analyze the IgG-like multi-specific antibodyfor dual Trop2 and Nectin-4 binding.[000352] Results: In order to demonstrate the potential of our sequences as immune engagers, IgG-like antibodies were constructed, produced in the cFAE method, comprised of two arms: one arm consists of a commercially available anti-CD3 binder, and the other arm consists of our dual binders of Trop2 / Nectin-4.[000353] Variant CID 1895 was constructed as a multi-specific antibody in an lgG1 DuoBody® format with a silent Fc (LALA mutation as described above). One arm is comprised of anti-CD3 binder (pacanalotamab), and the other is derived from variant CID 1895.[000354] ELISA EC- 50 analysis was performed to evaluate the dual binding of DuoBody® BDD2.012 (CID1895 x CD3) to Trop2 and Nectin-4 and compared to the binding of BDB2.014 (Sacituzumab x CD3 in Duo Body® format) and BDB2.019 (Enfortumab x CD3 in DuoBody® format) benchmarks (Figs. 10 A-11C). BDD2.012 binds human Trop2 with an EC-50 of 0.4nM and Nectin-4 with an EC- 50 of 1.41nM, as measured by ELISA. BDB2.014 (Sacituzumab x CD3 in DuoBody® format) binds Trop2 with an EC-50 of 0.49nM. BDB2.019 (Enfortumab x CD3 in DuoBody® format) binds Nectin-4 with an EC-50 of 0.53nM.[000355] Cell-based assay to demonstrate the functional activity of Trop2 / Nectin-4 dual binders as immune engagers in DuoBody® format[000356] Objective’. To evaluate T cell activation and cytotoxicity effect mediated by the hlgG-like multi-specific antibodies in a co-culture of T cells and TAA expressing cell lines.[000357] Results: Jurkat-Lucia™ NFAT effector cells were used to evaluate T cell activation by the Trop2 / Nectin-4xCD3 DuoBody® in co-culture with HEK293-Trop2, HEK293-Nectin-4 or MCF7 cell line, which expresses both targets. BDD2.012 (variant CID 1895 x CD3 in DuoBody® format) mediated engagement and activation of Jurkat-Lucia™ reporter T-cell line in co-culture of both HEK293-Trop2 (Fig. 12A), HEK293-Nectin-4 (Fig. 12B) and MCF7 (Fig. 12C) in a dose-dependent manner, with an EC-50 of 0.58nM over HEK293-Trop2, EC- 50 of 0.25nM over HEK293- Nectin-4 and EC-50 of 0.34nM over MCF7 cells. (See also the data in Table 6 for additional anti-Trop2 anti-Nectin-4 dual binding antibody clones) BDB2.014 (Sacituzumab x CD3 in DuoBody® format) mediated activation of the reporter cells only when co-cultured with T rop2 expressing cell lines. BDD2.015 (non-binding-control x CD3 in DuoBody® format) was used as negative control, and did not demonstrate activation of T cells in any of the co-culture assays.[000358] Peripheral blood mononuclear cells (PBMCs) were used to evaluate the immune cells cytotoxicity effects mediated by hlgG-like multi-specific antibodies in co-culture with HEK293-Trop2 and HEK293-Nectin-4 target cells. The tested DuoBody® molecules, comprised of one arm targeting CD3 and the other targeting Trop2 / Nectin-4, were evaluated for their ability to engage the T cell population present in PBMCs and promote their cytotoxic effect on the target cells. Viability of the target cells is measured by lactic acid dehydrogenase (LDH), an intracellular enzyme which is released to the supernatant upon cell death, and T cell activation is validated by measuring the levels of IFN-y in the supernatant. BDD2.012 (variant CID 1895 x CD3 in DuoBody® format) led to target cell death in a dose-dependent manner when PBMCs were co-cultured with both HEK293- Trop2 (Fig. 13A) and HEK293-Nectin-4 (Fig. 13B) target cells. BDD2.015 (non-binding- control x CD3 in DuoBody® format) was used as negative control and did not demonstrate activation of T cells in any of the co-culture assays. The high IFN-y measured in the supernatants (Figs. 14A and 14B) following incubation with BDD2.012 demonstrated additional validation for T cell activation. The lack of IFN-y release following incubation with the negative control BDD2.015 provides additional evidence that the observed killing facilitated by BDD2.012 is specifically due to the engagement and interaction between the T cells and the target cells, and not by non-specific T cell activation.[000359] Objective’. In the above experiments, the binding affinity was assessed in DuoBody® and BiTe® formats. In the following set of experiments, the affinity of the dual binding T rop2 / Nectin-4 antibodies was assessed. Antibody clones were formatted as h I gG 1 as elaborated in Table 9.[000360] The binding affinity of hlgG1 antibodies: BDG2.150, BDG2.182, BDG2.121, and BDG2.184 (clones CID-2054, CID-2822, CID-2040, and CID-2821 , respectively) was analyzed using an Enzyme-Linked Immunosorbent Assay (ELISA). The EC- 50 binding results are presented in Table 9 below.[000361] Table 9: EC-50 Binding affinity of representative dual antibodies (IgG formatted with LALA mutation) to hTrop2 and hNectin4, measured by ELISA assay.[000362] The results show that these dual binding antibodies have dual binding to Nectin4 and Trop2 with EC50 values of 2.1-3.7 nM and 0.63-0.98 nM, respectively, which is comparable to Enfortumab binding Nectin4 with an EC50 value of 1.2 nM, and Sacituzumab binding Trop2 at EC50 value of 0.8 nM.[000363] The binding kinetics of hlgG1 antibodies: BDG2.121 and BDG2.144 for antihuman and anti-cyno antibodies (clone CID 2040 with and without the Fc LALA mutations, respectively) was measured by SPR. Binding kinetics of CID 2040 to human T rop2 and cyno Trop2 are shown in Table 10. Binding kinetics of CID 2040 to human Nectin4 and cyno Nectin4 are shown in Table 11.[000364] Table 10: Binding kinetics of CID 2040 (hlgG1 format) to hTrop2 and cyno Trop2 as measured by SPR.* SPR values are for hlgG 1 with LALA mutation, similar results were obtained for CID 2040 without LALA mutation. ** SPR values are for hlgG1 format without LALA mutation.[000365] Table 11 : Binding kinetics of CID 2040 (hlgG1 format) to hNectin4 and cyno Nectin4.SPR values are for lgG1 with LALA mutation, similar results were obtained for CID 2040without LALA mutation.** SPR values are for lgG1 format without LALA mutation.[000366] The results show that clone 2040 in hlgG1 format, had a KD of 1.472 nM and 0.412 nM to human and cyno Trop2, respectively (Table 10); and KD of 11.3 nM and 11.5 nM to human and cyno Nectin-4, respectively (Table 11).Example 2: Trop2 / Nectin-4 Antibody and Internalization Assay[000367] Objective’. To evaluate the antigen-mediated antibody internalization capability of Trop2 / Nectin-4 dual binders into cells expressing Trop2 and Nectin-4 on their cell surface. In this way, the therapeutic potential of dual binding antibodies may be assessed.[000368] In this study, representative dual binding antibodies targeting Trop2 / Nectin4 were utilized to address the issue of tumor heterogeneity. The symmetrical hlgG multibodies (dual binding antibodies), designed with the assistance of antibody engineering platform, functions in an "OR" gate, capable of binding either Trop2 or Nectin4. This dual targeting strategy enables targeting tumor cells that express Trop2 and / or Nectin4 with enhancement of the therapeutic potential by leveraging improved internalization, e.g., in cells coexpressing both targets, while preserving the stability and developability properties of standard, well behaved IgGs. This approach aims to improve the precision and efficacy of ADCs in treating solid tumors.[000369] Representative variants were tested fortheir internalization capability in T47D and SK-BR-3 breast cancer cells: IgG ID#: BDG2.144 (CID 2040 in human lgG1 format), IgG ID#: BDG2.182 (CID 2822 in human lgG1 format), and IgG ID#: BDG2.201 (CID 2822 in human lgG1 L LA format). Enfortumab, Sacituzumab, and a human hlgG1 isotype nonbinding control (NBC) were used as reference and tested in an IgG format (for BDG2.144 and BDG2.182) or in an IgG LAL format (for BDG2.201).[000370] Methods:[000371] Antibody Internalization Assays for Live-Cell Analysis.[000372] The assay enables visualization and quantification of antibody internalization into the cells, as well as localization of the antibody within the cell. The assay was carried out according to the manufacturer instructions using Incucyte® Human Fabfluor-pH Orange Antibody Labeling Reagent (Sartorius, Germany; Cat# S4812).[000373] T47D breast cancer cells that express both Trop-2 and Nectin-4 (ATCC; Cat: HTB-133), were seeded at a concentration of 15,000 cells per well in a 96-well plate and incubated for24 hours at 37°C with 5% CO2 in RPMI-1640 medium (Gibco; Cat: 31870025). To pre-complex the tested antibodies with the labeling reagent (Fabfluor-pH-Ab complex), the tested antibodies were incubated for 15 minutes at 37°C with Incucyte® reagent at a 1 antibody:3 labeling reagent molar ratio. T47D cells were incubated with the tested antibodies pre-complexed with the labeling reagent at a final antibody concentration of 0.3 to 3 pg / ml as indicated. The multiwell-plate was then placed in the Incucyte® live-cell imaging system (Sartorius, Germany), and images were captured every 1.5 hours for 72 hours. Data analysis was conducted using the Incucyte® analysis software (Sartorius, Germany). The experiment was repeated as described using SK-BR-3 breast cancer (ATCC; Cat:HTB-30) cells to confirm the findings with T47D using 5,000 SK-BR-3 cells per well seeding density. [000374] The labeling reagent is pH dependent, at pH 7.0, the Fabfluor-pH-Ab complex has little or no fluorescence. When the labeled antibodies are internalized to cells, a fluorogenic signal is observed as the Fabfluor-pH-Ab complex is internalized and processed via acidic (pH 4.5-5.5) lysosomes and endosomes. When the labeled antibody is within the lysosome, the signal intensity increases.[000375] Internalization was measured by two parameters: the fluorescent area generated over time due to internalization of the labeled antibody into the cell; and by signal intensity, indicating localization of the labeled antibody in the endocytic vesicles and lysosomes. Parameter analysis was carried out according to the manufacturer’s recommendation.[000376] Resu / ts[000377] Representative Trop2 / Nectin-4 dual bindings antibodies BDG2.144 (CID2040) and BDG2.182 (CID2822), in hlgG1 format without LALA, and BDG2.201 (CID2822) in hlgG1 with LALA, exhibited higher levels of internalization intensity and kinetics in T47D cells (see top curves in Figs. 15A-15D compared to Sacituzumab and Enfortumab). Fig. 15A and Fig.15C show an analysis of antibody internalization by area indicating the level of antibody internalized. Fig. 15B and Fig. 15D show analysis of antibody internalization based on signal intensity, indicating the antibody’s localization in the endocytic vesicles and lysosomes. Imaging was captured at the indicated time points (X-axis) and the internalization by area (Y-axis in Fig. 15A and Fig. 15C) and internalization intensity (Y-axis in Fig. 15B and Fig. 15D) were assessed using the Incucyte® software. Fluorescent micrographs (not shown).[000378] In addition, the dose-dependent effect of the antibody concentration on the internalization level was examined as shown in Fig. 16A and Fig. 16B. For this purpose, T47D cells were incubated with the tested antibodies pre-complexed with the Fabfluor-pH labeling reagent as described above. Internalization of BDG2.144 (CID2040) and BDG2.182 (CID2822), in lgG1 format without LALA, BDG2.201 (CID2822) in lgG1 format with LALA, and the controls were tested at increasing concentrations of 0.03 to 3 pg / ml for 24 hours at 37°C using an Incucyte® system. Antibody internalization was measured by the integrated intensity per cell area over time. Analysis was carried out using the live imaging system described above.[000379] The dose-dependent effect on the internalization with the T47D breast cancer cell line is shown in Fig. 16A (for clones BDG2.144 (CID2040) and BDG2.182 (CID2822)) and Fig. 16B (for clone BDG2.201 (CID2822 with LALA)). The results indicate that the representative dual binding antibodies exhibited increased, dose-dependent levels of internalization compared to both Sacituzumab and Enfortumab mono-targeting antibodies. [000380] Representative results for the SK-BR-3 cell line showing antibody internalization and kinetics by signal area per cells area and signal intensity indicating the level of antibody internalized are shown in Fig. 17A and Fig. 17B for done BDG2.201, CID2822 with LALA. Results for the dose-dependent internalization for SK-BR-3 cells are shown in Fig. 18 for clone BDG2.201, CID2822 with LALA.[000381] These results show that the tested dual binding antibodies exhibited superior internalization characteristics as compared to monospecific antibody complexes and therefore can potentially be used to deliver cytotoxic drugs, e.g., in an ADC format, to cells expressing Trop2 / N ectin-4 on their cell surface, for increasing the therapeutic efficacy and / or reducing side-effect potential of the cytotoxic drug.[000382] These studies utilized T47D and SK-BR-3 breast cancer cells, but other cancerous tissues are known to co-express T rop2 and Nectin-4 on their cell surface, wherein the levels of Trop2 and Nectin-4 at the cell surface are greatly increased compared with healthy tissue. Thus, making any cancer tissue expressing either one or both antigens a therapeutic target for the antibodies disclosed herein.

Claims

CLAIMSWhat is claimed is:1 . An isolated Trop2 / N ectin-4 dual binding antibody or dual binding fragment thereof, said antibody or fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise:(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(c) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.

2. The isolated Tro p2 / N ectin-4 dual binding antibody or dual binding fragment thereof according to claim 1 , wherein the antibody or fragment thereof comprises a heavy chain variable domain (VH) and a light chain variable domain (VL), said VH and VL comprising the HCDR1 , HCDR2, and HCDR3 regions and the LCDR1 , LCDR2, and LCDR3 regions, respectively, and wherein the amino acid sequence of the VH and VL comprise:(a) SEQ ID NOs: 787 and 789, respectively;(b) SEQ ID NOs: 20 and 118, respectively; or(c) SEQ ID NOs: 786 and 788, respectively.

3. The isolated Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof according to claim 1 , wherein said antibody is in the form of an IgG, an Fv, an scFv, an Fab, a F(ab')2, a minibody, a diabody, or a triabody, wherein optionally said IgG comprises an lgG1, lgG2, lgG3, or lgG4.

4. The isolated Tro p2 / N ectin-4 dual binding antibody or dual binding fragment thereofaccording to claim 3, wherein when said antibody is in the form of an scFv dual binding fragment, the amino acid sequence of the scFv comprises:(a) SEQ ID NO: 811 ;(b) SEQ ID NO: 812; or(c) SEQ ID NO: 813.

5. The isolated Tro p2 / N ectin-4 dual binding antibody or dual binding fragment thereof according to claim 1 , wherein said antibody or fragment thereof is monovalent, bivalent, or multivalent.

6. The isolated Tro p2 / N ectin-4 dual binding antibody or dual binding fragment thereof according to claim 1 , wherein said antibody is a multi-specific antibody, an immunecell engager, a multi-engager, or a super-engager.

7. The isolated Tro p2 / N ectin-4 dual binding antibody or dual binding fragment thereof according to claim 1 , wherein said antibody is in the form of an antibody-drug- conjugate (ADC).

8. The isolated Tro p2 / N ectin-4 dual binding antibody or dual binding fragment thereof according to claim 1 , wherein the antibody or fragment thereof comprises (a) a mutation in the heavy chain (HC) and (b) has reduced binding or is unable to bind to fragment crystallizable gamma receptors (FcyRs), wherein reduced binding is compared with a Trop2 / N ectin-4 dual binding antibody or dual binding fragment thereof lacking the mutation in the heavy chain (HC) that affects FcyRs binding, and wherein optionally the mutation comprises a L234A L235A (LALA) mutation or a L234A L235A P329G (LALAPG) mutation.

9. The isolated Tro p2 / N ectin-4 dual binding antibody or dual binding fragment thereof according to claim 1 , wherein the antibody comprises a heavy chain (HC) and a light chain (LC), the amino acid sequences of said HC and LC pairs comprising:(a) SEQ ID NOs: 803 and 804, respectively;(b) SEQ ID NOs: 802 and 804, respectively;(c) SEQ ID NOs: 805 and 807, respectively;(d) SEQ ID NOs: 806 and 807, respectively;(e) SEQ ID NOs: 808 and 810, respectively; or(f) SEQ ID NOs: 809 and 810, respectively.

10. A composition comprising the isolated T rop2 / Nectin-4 dual binding antibody or dual binding fragment thereof according to claim 1 , and a pharmaceutically acceptable carrier.

11. An isolated polynucleotide encoding a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein said antibody or fragment thereof comprise three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain complementarity determining regions (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of the HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2, and LCDR3 comprise:(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(c) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.

12. The isolated polynucleotide according to claim 11 , the antibody or fragment thereof comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), said VH and VL comprising HCDR1 , HCDR2, and HCDR3 regions and LCDR1 , LCDR2 and LCDR3 regions, respectively, wherein the amino acid sequences of the VH and VL comprise:(a) SEQ ID NOs: 787 and 789, respectively;(b) SEQ ID NOs: 20 and 118, respectively; or(c) SEQ ID NOs: 786 and 788, respectively.

13. The isolated polynucleotide according to claim 11 , wherein said antibody orfragment thereof is in the form of an IgG, an Fv, an scFv, an Fab, a F(ab')2, a minibody, a diabody, or a triabody, and wherein optionally said IgG comprises an lgG1 , lgG2, lgG3, or lgG4.

14. The isolated polynucleotide according to claim 13 encoding an anti-Trop2 / Nectin-4 dual binding scFv, the amino acid sequence of the scFv comprising:(a) SEQ ID NO: 811 ;(b) SEQ ID NO: 812; or(c) SEQ ID NO: 813.

15. An expression vector comprising the polynucleotide according to claim 11 .

16. A host cell comprising the expression vector of claim 15.

17. A method of treating a subject suffering from a disease or condition, said method comprising administering to said subject(i) a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, said antibody or fragment thereof comprising three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, and LCDR3, wherein the amino acid sequences of HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 comprise:(a) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(b) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(c) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively; or(ii) a polynucleotide encoding a Trop2 / Nectin-4 dual binding antibody or dual binding fragment thereof, wherein the antibody or fragment thereof comprises three heavy chain complementarity determining regions (CDRs) HCDR1 , HCDR2, and HCDR3 and three light chain (CDRs) LCDR1 , LCDR2, and LCDR3, and wherein the amino acid sequencesof HCDR1 , HCDR2, HCDR3, LCDR1 , LCDR2 and LCDR3 comprise:(d) SEQ ID NO: 791 , SEQ ID NO: 793, SEQ ID NO: 795, SEQ ID NO: 797, SEQ ID NO: 799, and SEQ ID NO: 801 , respectively;(e) SEQ ID NO: 216, SEQ ID NO: 314, SEQ ID NO: 412, SEQ ID NO: 510, SEQ ID NO: 608, and SEQ ID NO: 706, respectively; or(f) SEQ ID NO: 790; SEQ ID NO: 792; SEQ ID NO: 794, SEQ ID NO: 796, SEQ ID NO: 798, and SEQ ID NO: 800, respectively.

18. The method of claim 17, wherein said disease or condition is cancer, wherein optionally the cancer comprises a solid tumor, a hematopoietic malignancy, a metastatic cancer, or an unresectable cancer, or a combination thereof.

19. The method of claim 18, wherein said solid tumor expresses T rop2 and Nectin-4 on its cell surface, expresses Trop2 but not Nectin-4 on its cell surface, or expresses Nectin-4 but not Trop2 on its cell surface.

20. An isolated T rop2 / Nectin-4 dual binding antibody or a dual binding fragment thereof, comprising a heavy chain variable domain (VH) and a light chain variable domain (VL) wherein the amino acid sequences of the VH and VL comprise:(a) SEQ ID NOs: 787 and 789, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 787 and 789, respectively;(b) SEQ I D NOs: 20 and 118, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 20 and 118, respectively; or(c) SEQ ID NOs: 786 and 788, respectively, or homologs thereof having at least 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NOs: 786 and 788, respectively; and wherein the dual binding antibody or the dual binding fragment thereof binds T rop2 and Nectin-4 within the same Fv region.

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