Antibodies to truncated CDCP1 and uses thereof

Abstract

The present disclosure provides an antibody or antigen-binding fragment thereof that specifically binds to truncated CDCP1, and a method of using the same. In some embodiments, the present disclosure is directed to a method of treating cancer in a subject, comprising administering to the subject an antibody or antigen-binding fragment thereof that specifically binds to truncated human CDCP1.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 63 / 170,338, filed April 2, 2021, the contents of which are incorporated herein by reference in their entirety.

[0002] References to sequence listings submitted electronically via EFS-WEB The contents of the Sequence Listing filed with this application as an electronically submitted ASCII text file (Name: 3338_242PC01_Seqlisting_ST25.txt, Size: 426,827 bytes, and Creation Date: March 31, 2022) are incorporated herein by reference in their entirety.

[0003] The present disclosure provides antibodies that specifically bind to truncated CDCP1 (e.g., human or mouse CDCP1), and antigen-binding fragments thereof, compositions comprising such antibodies, and methods of using such antibodies to prevent or treat diseases or conditions, including tumors (e.g., cancers with truncated CDCP1 present on the surface of cancer cells), in a subject. [Background technology]

[0004] CUB domain-containing protein 1 (CDCP1) CDCP1 is a 135kDa, heavily glycosylated, single-pass transmembrane protein of largely unknown function. See, e.g., Stephen, AG et al., Cancer Cell, 25(3):272-281 (2014); Papke, B. et al., Science, 355(6330):1158-1163 (2017). Overexpression of CDCP1 correlates with increased malignancy and poor prognosis in pancreatic, lung, colon, kidney, breast, and prostate cancers. See, for example, Martinko, AJ et al., eLife, 7:e31098 (2018); Uekita, T. et al., Cancer Science, 102 (11):1943-1948 (2011); Scherl-Mostager, M. et al., Oncogene, 20(32):4402-4408 (2001). CDCP1 has also been found to be upregulated in K-Ras-activated cancer cells and is crucial for their growth. See, for example, Uekita, T. et al., Cancer Science, 102 (11):1943-1948 (2011).

[0005] CDCP1 is likely proteolytically processed between the first and second CUB domains by serine proteases. See, for example, Casar, B. et al., Oncogene 33:255-268 (2014). Proteolysis, along with overexpression, is associated with CDCP1 activation. See, for example, He, Y. et al., Oncogene 35:468-478 (2016); Brown, TA et al., J. Biol. Chem. 279:14772-14783 (2004). There is strong evidence that both CDCP1 overexpression and proteolytic activation contribute to the loss of cell adhesion, increased migration, and poor prognosis / survival in cancer patients. See, for example, Uekita, T. et al., Cancer Science, 102 (11):1943-1948 (2011); Casar, B. et al., Oncogene 33:255-268 (2014).

[0006] Furthermore, truncated CDCP1 has been shown to be more abundant in aggressive cancers, see, e.g., Wright, HJ et al. Oncogene, 35:4762-4772 (2016), Adams, MN et al., Oncogene 34: 1375-1383 (2015), He, Y. et al., J. Biol. Chem., 285:26162-26173 (2010), while CDCP1 on normal tissues has been found to be primarily the full-length form. See, for example, Alvares, SM, et al., Biochim. Biophys. Acta - Gen. Subj., 1780: 486-496 (2008); McGovern, JA et al., Br. J. Dermatol., 168: 496-503 (2013); Wong, CH et al., Clin. Cancer Res., 15:2311-2322 (2009). Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an antibody that specifically binds to truncated human CDCP1 can be used for the diagnosis, prevention, or treatment of diseases in which truncated CDCP1 is overexpressed (e.g., K-Ras-driven tumors).Therefore, it is necessary to develop an antibody that specifically binds to truncated CDCP1 and can regulate the activity of truncated CDCP1. [Means for solving the problem]

[0008] One aspect of the present disclosure is directed to an isolated antibody or antigen-binding fragment thereof that specifically binds to truncated human complement C1r / C1s, Uegf, Bmp1 (CUB) domain-containing protein 1 (CDCP1), wherein the antibody or antigen-binding fragment thereof preferentially binds to truncated CDCP1.

[0009] In some embodiments, the antibodies or antigen-binding fragments thereof of the present disclosure do not bind to full-length human CDCP1 at detectable levels.

[0010] In some embodiments, the binding between the antibody or antigen-binding fragment thereof and truncated CDCP1 or full-length CDCP1 is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

[0011] In some embodiments, the truncated CDCP1 comprises a first cleavage domain and a second cleavage domain, wherein the first cleavage domain and the second cleavage domain are not linked.

[0012] In some embodiments, the truncated CDCP1 comprises a membrane-associated complex.

[0013] In some embodiments, the first truncated domain consists of the amino acid sequence set forth in SEQ ID NO: 63, 68, or 74.

[0014] In some embodiments, the second truncated domain consists of the amino acid sequence set forth in SEQ ID NO: 64, 70, or 77.

[0015] In some embodiments, the truncated CDCP1 is generated by truncating at residues K365, R368, and / or K369 of SEQ ID NO:273.

[0016] In some embodiments, the truncated CDCP1 is post-translationally modified, and the post-translational modifications include phosphorylation and N-linked glycosylation.

[0017] Some embodiments of the present disclosure relate to an isolated antibody or antigen-binding fragment thereof that specifically binds to truncated human CDCP1 and comprises a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises VL complementarity-determining region (CDR) 1, VL-CDR2, and VL-CDR3, and the VH comprises SEQ ID NOs: 1 (SVSSAVA), 2 (SASSLY), 268 (SX1X2X3X4X5), 269 (X6FSSX7SI), 270 (SIYPYSGSTX8), and 271 (X9X 10 X 12 SX 12 YSHTWWVSYGX 13 ) or 272(X 14 YWVX 15 FWYGHFSYYRPAL), X1 = glycine (G), serine (S), methionine (M), leucine (L), valine (V), or arginine (R); X2 = glutamine (Q), serine (S), glutamic acid (E), asparagine (N), lysine (K), proline (P), arginine (R), leucine (L), or histidine (H); X3 = arginine (R), serine (S), valine (V), tryptophan (W), leucine (L), lysine (K), methionine (M), glutamine (Q), or proline (P); X4 = proline (P), leucine (L), threonine (T), or serine (S); X5 = isoleucine (I), alanine (A), methionine (M), lysine (K), valine (V), leucine (L), phenylalanine (F); X6 = no amino acid, aspartic acid (D), or asparagine (N); X7 = serine (S) or tyrosine (Y); X8 = serine (S) or tyrosine (Y); X9 = glutamine (Q), arginine (R), or lysine (K); X 10 = serine (S), asparagine (N), threonine (T), glycine (G), alanine (A), or aspartic acid (D); X 11 = glutamine (Q) or histidine (H), X 12 = tyrosine (Y) or phenylalanine (F), X 13 = methionine (M), alanine (A), isoleucine (I), leucine (L), or valine (V); X 14 = threonine (T) or isoleucine (I), X 15 = glutamine (Q) or aspartic acid (D), The present invention relates to isolated antibodies or antigen-binding fragments thereof.

[0018] Some embodiments of the present disclosure relate to an isolated antibody or antigen-binding fragment thereof that specifically binds to truncated human CDCP1, and comprises a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises a VL complementarity-determining region (CDR) 1 sequence of SEQ ID NO: 1 (SVSSAVA), a VL-CDR2 sequence of SEQ ID NO: 2 (SASSLY), and a VL-CDR3 sequence of SEQ ID NO: 8 (TGQRPM), 23 (FMRPAF), 16 (TAQSPL), 11 (VELVPM), 12 (AGKRPL), or 14 (LGVRAA), respectively; and the VH comprises a VH-CDR 1 sequence of SEQ ID NO: 269 (X1FSSX2SI), a VH-CDR2 sequence of SEQ ID NO: 270 (SIYPYSGSTX3), and a VH-CDR3 sequence of SEQ ID NO: 271 (X4X5X6SX7YSHTWWVSYGX8) or SEQ ID NO: 272 (X9YWVX 10 FWYGHFSYYRPAL), X1 = no amino acid, aspartic acid (D), or asparagine (N); X2 = serine (S) or tyrosine (Y); X3 = serine (S) or tyrosine (Y); X4 = glutamine (Q), arginine (R), or lysine (K); X5 = serine (S), asparagine (N), threonine (T), glycine (G), alanine (A), or aspartic acid (D); X6 = glutamine (Q) or histidine (H); X7 = tyrosine (Y) or phenylalanine (F); X8 = methionine (M), alanine (A), isoleucine (I), leucine (L), or valine (V); X9 = threonine (T) or isoleucine (I); X 10 = glutamine (Q) or aspartic acid (D), The present invention relates to isolated antibodies or antigen-binding fragments thereof.

[0019] In some embodiments, an isolated antibody or antigen-binding fragment thereof of the present disclosure comprises a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises a VL complementarity-determining region (CDR) 1, a VL-CDR2, and a VL-CDR3, and the VH comprises a VH-CDR1, a VH-CDR2, and a VH-CDR3, wherein the VL-CDR3 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 3-25. In some embodiments, the VL-CDR2 comprises the amino acid sequence of SEQ ID NO: 2. In some embodiments, the VL-CDR1 comprises the amino acid sequence of SEQ ID NO: 1. In some embodiments, the VH-CDR1 comprises the amino acid sequence selected from the group consisting of SEQ ID NOs: 26-29, 109, and 111. In some embodiments, the VH-CDR2 comprises the amino acid sequence of SEQ ID NO: 30 or 31. In some embodiments, the VH-CDR3 comprises the amino acid sequence selected from the group consisting of SEQ ID NOs: 20, 32-47, and 105.

[0020] In some embodiments, VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 32.

[0021] In some embodiments, VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 33.

[0022] In some embodiments, VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 34.

[0023] In some embodiments, VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 35; or

[0024] In some embodiments, VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 36.

[0025] In some embodiments, an antibody or antigen-binding fragment thereof of the present disclosure comprises a VH comprising an amino acid sequence of at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 61, 65, 67, 69, 71, 73, 75, 79, 80, 81, 82, 83, 84, 85, 86, 87, 89, 91, 99, 103, 107, 123, and 133.

[0026] In some embodiments, an antibody or antigen-binding fragment thereof of the present disclosure comprises a VH comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 61, 65, 67, 69, 71, 73, 75, 79, 80, 81, 82, 83, 84, 85, 86, 87, 89, 91, 99, 103, 107, 123, and 133.

[0027] In some embodiments, an antibody or antigen-binding fragment thereof of the present disclosure comprises a VL comprising an amino acid sequence of at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 62, 76, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, and 132.

[0028] In some embodiments, an antibody or antigen-binding fragment thereof of the present disclosure comprises a VL comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 62, 76, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, and 132.

[0029] In some embodiments, an antibody or antigen-binding fragment thereof of the present disclosure comprises a VH and a VL, (a) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 61, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (b) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (c) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 67, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (d) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 69, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (e) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 71, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (f) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 73, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (g) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 75, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (h) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 79, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (i) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (j) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 83, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (k) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 85, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (l) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 87, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (m) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 89, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (n) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 91, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (o) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 94; (p) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 96; (q) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 98; (r) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 100; (s) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 102; (t) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 103, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 104; (u) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 106; (v) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 108; (w) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 110; (x) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 112; (y) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 114; (aa) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 116; (bb) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 118; (cc) the VH comprises the amino acid sequence set forth in SEQ ID NO: 65 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 120; (dd) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 122; (ee) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 123 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 124; (ff) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 126; (gg) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 128; (hh) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 130; (ii) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 132; (jj) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 133, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (kk) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 80, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (ll) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 81, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (mm) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 82, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (nn) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 84 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; or (oo) The VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 86, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62.

[0030] Some embodiments of the present disclosure provide an isolated antibody or antigen-binding fragment thereof that specifically binds to the same truncated human CDCP1 epitope as a reference antibody comprising a heavy chain variable region (VH) and a light chain variable region (VL), (a) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 61, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (b) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (c) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 67, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (d) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 69, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (e) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 71, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (f) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 73, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (g) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 75, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (h) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 79, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (i) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (j) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 83, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (k) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 85, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (l) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 87, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (m) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 89, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (n) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 91, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (o) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 94; (p) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 96; (q) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 98; (r) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 100; (s) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 102; (t) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 103, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 104; (u) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 106; (v) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 108; (w) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 110; (x) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 112; (y) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 114; (aa) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 116; (bb) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 118; (cc) the VH comprises the amino acid sequence set forth in SEQ ID NO: 65 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 120; (dd) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 122; (ee) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 123 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 124; (ff) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 126; (gg) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 128; (hh) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 130; (ii) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 132; or (jj) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 133, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (kk) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 80, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (ll) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 81, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (mm) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 82, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (nn) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 84 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; or (oo) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 86, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; The present invention relates to isolated antibodies or antigen-binding fragments thereof.

[0031] Some embodiments of the present disclosure provide an isolated antibody or antigen-binding fragment thereof that cross-competes with a reference antibody comprising a heavy chain variable region (VH) and a light chain variable region (VL) for binding to a truncated human CDCP1 epitope, the antibody or antigen-binding fragment thereof comprising: (a) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 61, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (b) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (c) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 67, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (d) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 69, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (e) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 71, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (f) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 73, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (g) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 75, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (h) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 79, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (i) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (j) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 83, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (k) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 85, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (l) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 87, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (m) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 89, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (n) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 91, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (o) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 94; (p) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 96; (q) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 98; (r) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 100; (s) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 102; (t) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 103, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 104; (u) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 106; (v) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 108; (w) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 110; (x) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 112; (y) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 114; (aa) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 116; (bb) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 118; (cc) the VH comprises the amino acid sequence set forth in SEQ ID NO: 65 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 120; (dd) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 122; (ee) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 123 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 124; (ff) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 126; (gg) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 128; (hh) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 130; (ii) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 132; or (jj) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 133, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (kk) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 80, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (ll) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 81, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (mm) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 82, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (nn) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 84 and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; or (oo) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 86, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; The present invention relates to isolated antibodies or antigen-binding fragments thereof.

[0032] In some aspects, the antibody or antigen-binding fragment thereof of the present disclosure: (a) the antibody inhibits tumor growth and / or metastasis; (b) the antibody reduces tumor volume; (c) the antibody increases progression-free survival; (d) the antibody increases overall survival; (e) the antibody promotes CDCP1 internalization and / or degradation; and (f) any combination of these The compound has one or more properties selected from the group consisting of:

[0033] In some embodiments, the antibody or antigen-binding fragment thereof of the present disclosure is at about 1 x 10 -4 K below M D It specifically binds to truncated human CDCP1 and D is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

[0034] In some embodiments, the antibody or antigen-binding fragment thereof of the present disclosure is at about 1 x 10 -4 On-rate (k on ) specifically binds to truncated human CDCP1 and k on The rate is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

[0035] In some embodiments, the antibody or antigen-binding fragment thereof of the present disclosure is at about 1 x 10 -4 Off-rate (k off ) specifically binds to truncated human CDCP1 and k off is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

[0036] In some embodiments, the antibodies or antigen-binding fragments thereof of the present disclosure bind to truncated cynomolgus CDCP1.

[0037] In some embodiments, the antibody or antigen-binding fragment thereof of the present disclosure is selected from the group consisting of IgG1, IgG2, IgG3, IgG4, or variants thereof.

[0038] In some embodiments, the antibody or antigen-binding fragment of the disclosure is an IgG1 antibody.

[0039] In some embodiments, the antibodies or antigen-binding fragments of the present disclosure have been modified to remove glycosylation sites, hi some embodiments, removal of glycosylation sites is achieved via substitution of asparagine (N) with aspartic acid (D) at the position corresponding to residue 31 of SEQ ID NO:61.

[0040] In some embodiments, an antibody or antigen-binding fragment of the present disclosure comprises a substitution of alanine (A), isoleucine (I), leucine (L), or valine (V) for methionine (M) at a position corresponding to residue 114 of SEQ ID NO: 61 or 65.

[0041] In some aspects, the antibodies of the present disclosure are human, humanized, chimeric, or antigen-binding fragments thereof.

[0042] In some aspects, the antibodies or antigen-binding fragments of the present disclosure are suitable for administration to a human subject.

[0043] In some aspects, the antibodies or antigen-binding fragments of the present disclosure are full-length antibodies.

[0044] In some embodiments, the antibodies or antigen-binding fragments of the present disclosure are antigen-binding fragments, such as Fab, Fab', F(ab')2, single-chain Fv (scFv), disulfide-linked Fv, IgNar, intrabody, IgGΔCH2, minibody, F(ab')3, tetrabody, triabody, diabody, single domain antibody, DVD-Ig, Fcab, mAb. 2 , (scFv)2, or scFv-Fc.

[0045] Some aspects of the present disclosure are directed to bispecific antibodies comprising the antibodies or antigen-binding fragments described herein.

[0046] Some aspects of the present disclosure are directed to multispecific antibodies, including bispecific antibodies or antibodies or antigen-binding fragments thereof described herein.

[0047] In some aspects, an antibody or antigen-binding fragment thereof, bispecific antibody, or multispecific antibody of the present disclosure further comprises a detectable label.

[0048] Some aspects of the present disclosure are directed to a polynucleotide or set of polynucleotides that encodes an antibody or antigen-binding fragment thereof, a bispecific antibody, or a multispecific antibody of the disclosure.

[0049] In some aspects, the polynucleotide comprises a nucleic acid molecule encoding the heavy chain variable region or heavy chain of an antibody or antigen-binding fragment thereof of the present disclosure.

[0050] In some embodiments, a nucleic acid molecule of the disclosure encodes a VH of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227.

[0051] In some aspects, the polynucleotide comprises a nucleic acid molecule encoding the light chain variable region or light chain of an antibody or antigen-binding fragment thereof of the present disclosure.

[0052] In some embodiments, the nucleic acid molecule encodes a VL of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

[0053] In some embodiments, a polynucleotide of the disclosure comprises a first nucleic acid molecule encoding a heavy chain variable region of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227, and a second nucleic acid molecule encoding a light chain variable region of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

[0054] In some embodiments, the mixture of polynucleotides of the present disclosure comprises a first polynucleotide comprising a nucleic acid molecule encoding a heavy chain variable region of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227, and a second polynucleotide comprising a nucleic acid molecule encoding a light chain variable region of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

[0055] In some aspects, the polynucleotides of the present disclosure comprise nucleic acid molecules encoding the heavy chain variable region or heavy chain of an antibody or antigen-binding fragment thereof disclosed herein, and the light chain variable region or light chain of an antibody or antigen-binding fragment thereof disclosed herein.

[0056] In some aspects, the vector comprises a polynucleotide disclosed herein.

[0057] In some embodiments, the host cell comprises (a) an antibody or antigen-binding fragment thereof, (b) a bispecific antibody, (c) a multispecific antibody, (d) a polynucleotide, (e) a vector, or (f) a first vector comprising a polynucleotide and a second vector comprising a polynucleotide, as disclosed herein.

[0058] In some embodiments, the host cell is selected from the group consisting of E. coli, Pseudomonas, Bacillus, Streptomyces, yeast, HPAC, PL5, PL45, HPNE, Expi293F human cells, C6 (rat glioma cell line), U2OS, Chem-1, CHO, YB / 20, NS0, PER-C6, HEK-293T, HEK293T-cCDCP1, NIH-3T3, HeLa, BHK, Hep G2, SP2 / 0, R1.1, BW, LM, COS1, COS7, BSC1, BSC40, BMT10 cells, PANC-1, Panc 03.27, Hs766T, CFPAC-1, CAPAN-1, Mia, and the like in tissue culture. Selected from the group consisting of PaCa-2, CAPAN-2, BXPC3, mouse Fc1245, mouse Fc1242, mouse Fc1245-cCDCP1, mouse PyMT, mouse P53, mouse 4T1, mouse EMT6, mouse TRAMP, mouse C2, mouse MC38, mouse CT26, plant cells, insect cells, and human cells.

[0059] In some embodiments, provided herein is an immunoconjugate comprising an antibody or antigen-binding fragment thereof, bispecific antibody, or multispecific antibody of the present disclosure and a therapeutic agent. In some embodiments, the therapeutic agent is selected from the group consisting of a cytotoxin, a non-cytotoxic drug, a radioactive agent, a second antibody, an enzyme, an anti-neoplastic agent, and any combination thereof.

[0060] Some embodiments of the present disclosure are directed to methods for producing an antibody or antigen-binding fragment thereof that binds to a truncated human CDCP1, the method comprising culturing a host cell disclosed herein to express the nucleic acid molecule and produce the antibody or antigen-binding fragment thereof. In some embodiments, the method further comprises isolating the antibody or antigen-binding fragment thereof from the culture.

[0061] In some embodiments, the isolated antibody or antigen-binding fragment thereof that specifically binds to truncated human CDCP1 is encoded by a polynucleotide disclosed herein or produced by a method disclosed herein.

[0062] Some aspects of the present disclosure are directed to pharmaceutical compositions comprising an antibody or antigen-binding fragment, bispecific antibody, multispecific antibody, polynucleotide, vector, or immunoconjugate of the present disclosure and a pharmaceutically acceptable excipient.

[0063] In some aspects, the pharmaceutical compositions disclosed herein are formulated for intravenous, intraperitoneal, intramuscular, intraarterial, intrathecal, intralymphatic, intralesional, intracapsular, intraorbital, intracardiac, intradermal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal, epidural, intrasternal, topical, epidermal, or mucosal administration.

[0064] Some aspects of the present disclosure are directed to methods of treating cancer in a subject in need thereof, comprising administering to the subject an antibody or antigen-binding fragment thereof, bispecific antibody, multispecific antibody, polynucleotide, vector, immunoconjugate, or pharmaceutical composition disclosed herein.

[0065] In some aspects, the antibodies or antigen-binding fragments thereof disclosed herein reduce or inhibit metastasis of cancer in a subject.

[0066] Some aspects of the present disclosure are directed to methods of reducing or inhibiting metastasis of cancer in a subject in need thereof, comprising administering to the subject an antibody or antigen-binding fragment thereof, bispecific antibody, multispecific antibody, polynucleotide, vector, immunoconjugate, or pharmaceutical composition disclosed herein.

[0067] In some embodiments, the subject is suffering from cancer.

[0068] In some embodiments, the cancer has a truncated CDCP1 present on the surface of the cancer cells.

[0069] In some embodiments, the cancer comprises a tumor.

[0070] In some embodiments, the cancer is small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC), squamous NSCLC, non-squamous NSCLC, glioma, gastrointestinal cancer, renal cancer, clear cell carcinoma, ovarian cancer, liver cancer, colorectal cancer, endometrial cancer, kidney cancer, renal cell carcinoma (RCC), prostate cancer, hormone-refractory prostate adenocarcinoma, thyroid cancer, neuroblastoma, pancreatic cancer, glioblastoma (glioblastoma polymorphism), cervical cancer, gastric cancer, bladder cancer, hepatocellular carcinoma (hepatocellular carcinoma), breast cancer, colon cancer, head and neck cancer (or cancer), head and neck squamous cell carcinoma (HNSCC), gastric cancer, germ cell tumors, pediatric meat cancer, or tumors, sinonasal natural killer, melanoma, metastatic malignant melanoma, cutaneous or intraocular malignant melanoma, mesothelioma, bone cancer, skin cancer, uterine cancer, cancer of the anal region, testicular cancer, cancer of the fallopian tubes, cancer of the endometrium, cancer of the cervix, cancer of the vagina, cancer of the vulva, cancer of the esophagus, cancer of the small intestine, cancer of the endocrine system, cancer of the parathyroid gland, cancer of the adrenal gland, soft tissue sarcoma, cancer of the urethra, cancer of the penis, solid tumors of childhood, cancer of the ureter, cancer of the renal pelvis, neoplasms of the central nervous system (CNS), primary CNS lymphoma, tumor angiogenesis, spinal axis tumors, brain cancer, brain stem glioma, pituitary adenoma, Kaposi's sarcoma, epidermoid carcinoma, squamous cell carcinoma , environmentally induced cancers including those induced by asbestos, virus-associated cancers or cancers of viral origin, tumors associated with or of viral origin with human papillomavirus (HPV), acute leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myeloid leukemia (CML), anaplastic AML, myeloblastic leukemia, myeloblastic leukemia, promyelocytic leukemia, myelomonocytic leukemia, monocytic leukemia, erythroleukemia, megakaryoblastic leukemia, solitary granulocytic sarcoma, chloroma, Hodgkin's lymphoma (HL), non-Hodgkin's lymphoma (NHL), B-cell lymphoma lymphoma, T-cell lymphoma, lymphoplasmacytic lymphoma, monocytoid B-cell lymphoma, mucosa-associated lymphoid tissue (MALT) lymphoma, anaplastic large cell lymphoma, adult T-cell lymphoma / leukemia, mantle cell lymphoma, angioimmunoblastic T-cell lymphoma, angiocentric lymphoma, intestinal T-cell lymphoma, primary mediastinal B-cell lymphoma, precursor T-lymphoblastic lymphoma, T-lymphoblastic, peripheral T-cell lymphoma, lymphoblastic lymphoma, post-transplant lymphoproliferative disorder, true histiocytic lymphoma, primary central nervous system lymphoma, primary effusion lymphoma, lymphoblastic lymphoma (LBL),Hematopoietic tumors of lymphoid lineage, acute lymphoblastic leukemia, diffuse large B-cell lymphoma, Burkitt's lymphoma, follicular lymphoma, diffuse histiocytic lymphoma (DHL), immunoblastic large cell lymphoma, precursor B-lymphoblastic lymphoma, cutaneous T-cell lymphoma (CTLC), lymphoplasmacytic lymphoma with Waldenstrom's macroglobulinemia (LPL), myeloma, IgG myeloma, light chain myeloma, non-secretory myeloma, smoldering myeloma (asymptomatic myeloma), solitary plasmacytoma, multiple myeloma, chronic lymphocytic leukemia (CLL), hairy cell lymphoma, and any combination of the above cancers.

[0071] Some aspects of the present disclosure are directed to methods of killing tumor cells in a subject in need thereof, comprising administering an antibody or antigen-binding fragment thereof, bispecific antibody, multispecific antibody, polynucleotide, vector, immunoconjugate, or pharmaceutical composition of the present disclosure.

[0072] In some embodiments, the tumor cells are metastatic.

[0073] In some aspects, the methods of the present disclosure further comprise administering to the subject an additional anti-cancer therapy.

[0074] In some embodiments, the additional anti-cancer therapy comprises chemotherapy, immunotherapy, surgery, radiation therapy, or any combination thereof.

[0075] In some embodiments, the additional anti-cancer therapy comprises a standard of care therapy.

[0076] In some embodiments, the additional anti-cancer therapy comprises a checkpoint inhibitor.

[0077] In some embodiments, the additional anti-cancer therapy is selected from the group consisting of inducible T-cell costimulatory factor (ICOS), CD137 (4-1BB), CD134 (OX40), NKG2A, CD27, CD96, glucocorticoid-induced TNFR-related protein (GITR), and herpesvirus entry mediator (HVEM), programmed death-1 (PD-1), programmed death-ligand-1 (PD-L1), CTLA-4, B- and T-lymphocyte attenuating factor (BTLA), T-cell immunoglobulin and mucin domain-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), adenosine The antibodies or antigen-binding fragments thereof specifically bind to a protein selected from A2a receptor (A2aR), killer cell lectin-like receptor G1 (KLRG-1), natural killer cell receptor 2B4 (CD244), CD160, T cell immunoreceptor with Ig and ITIM domains (TIGIT), and receptor for V-domain Ig suppressor of T cell activation (VISTA), KIR, TGFβ, IL-10, IL-8, B7-H4, Fas ligand, CXCR4, mesothelin, CEACAM-1, CD52, HER2, and any combination thereof.

[0078] In some embodiments, the anti-PD-1 antibody comprises nivolumab or pembrolizumab.

[0079] In some embodiments, the additional anti-cancer therapy comprises CAR-T cell therapy.

[0080] In some aspects, an antibody or antigen-binding fragment thereof, bispecific antibody, multispecific antibody, polynucleotide, vector, host cell, immunoconjugate, or pharmaceutical composition of the disclosure is administered intravenously, intraperitoneally, intramuscularly, intra-arterially, intrathecally, intralymphatically, intralesionally, intracapsular, intraorbital, intracardially, intradermally, transtracheally, subcutaneously, subcuticularly, intra-articularly, subcapsularly, subarachnoidally, intraspinally, epidurally, intrasternally, topically, epidermally, or mucosally.

[0081] In some embodiments, the subject is a human.

[0082] Some embodiments of the present disclosure are directed to methods for detecting truncated human CDCP1 in a sample, comprising contacting the sample with an antibody or antigen-binding fragment thereof, bispecific antibody, multispecific antibody, immunoconjugate, or pharmaceutical composition of the present disclosure.

[0083] In some embodiments, the sample is obtained from a human subject. In some embodiments, the sample is a cancer sample. In some embodiments, the sample is an in vitro sample.

[0084] Some aspects of the present disclosure are directed to a method for identifying a cancer drug candidate, comprising generating an antibody or antigen-binding fragment thereof that specifically binds to a truncated CDCP1 disclosed herein, wherein the antibody or antigen-binding fragment thereof preferentially binds to the truncated CDCP1.

[0085] In some embodiments, the truncated CDCP1 is produced by (a) culturing a host cell comprising a first polynucleotide encoding a first cleavage domain and a second polynucleotide encoding a second cleavage domain, and (b) isolating the truncated CDCP1.

[0086] Some embodiments of the present disclosure are directed to an isolated antigen that consists of, or consists essentially of, a proteolytically truncated CDCP1 protein. In some embodiments, the truncated CDCP1 is (i) SEQ ID NOs: 63 and 64, respectively; (ii) SEQ ID NOs: 68 and 70, respectively; or (iii) SEQ ID NOs: 74 and 77, respectively It is a complex of an N-terminal fragment of CDCP1 having the amino acid sequence described in and a C-terminal fragment of CDCP1.

[0087] Other features and advantages of the present disclosure will become apparent from the following detailed description and examples, which should not be construed as limiting. The contents of all cited references, including scientific literature, newspaper articles, GenBank entries, patents, and patent applications cited throughout this application, are expressly incorporated herein by reference. [Brief explanation of the drawings]

[0088] [Figure 1A] FIG. 1A shows a schematic diagram of the design of CDCP1(Px)-Fc, in which the PreScission protease-cleavable CDCP1 ectodomain is fused to a TEV-releasable Fc domain with a C-terminal Avi tag, according to Example 2. [Figure 1B] Figure 1B shows an image of an SDS-PAGE gel of the engineered CDCP1 antigen from Example 2. Note that the NTF is heavily glycosylated and therefore runs as a smeared high molecular weight band of approximately 60 kDa. [Figure 1C] Figure 1C shows SEC traces of CDCP1(R368 / K369A)-Fc, CDCP1(Px)-Fc treated with PreScission protease, and NTF (TEV released) from Example 2. Numbers indicate fractions corresponding to the lanes of the SDS-PAGE gel in Figure 1B. [Figure 1D] FIG. 1D shows a graphical representation of the results obtained by a BLI assay performed according to Example 2. [Figure 1E] FIG. 1E shows a schematic diagram of PreScission protease-cleavable CDCP1 whole protein with an N-terminal FLAG tag expressed on the surface of HEK293T cells according to Example 2. [Figure 1F] FIG. 1F shows the results of flow cytometry (top) and Western blot analysis (bottom) of HEK293T-wt, HEK293T-CDCP1(R368A / K369A), and HEK293T-CDCP1(Px) according to Example 2. [Figure 1G]FIG. 1G shows a schematic diagram of a mutant comprising an NTF fused to an Fc domain (NTF-Fc), generated according to Example 2. [Figure 1H] FIG. 1H shows a graphical representation of the results obtained by the BLI assay according to Example 2. [Figure 1I] FIG. 1I shows an image of an SDS-PAGE gel of thrombin protease-cleavable CDCP1-Fc (CDCP1(Tx)-Fc) according to Example 2. [Figure 1J] FIG. 1J shows a graphical representation of the results obtained by the BLI assay according to Example 2. [Figure 1K] FIG. 1K shows the SEC trace of CDCP1(Tx)-Fc treated or not with thrombin protease according to Example 2. [Figure 2A] FIG. 2A shows a schematic diagram of the IP-MS strategy used to identify endogenous proteolytic sites of CDCP1 on PDAC cells according to Example 3. [Figure 2B] Figure 2B shows an image of a Western blot (top) of PDAC cell lines expressing differential amounts of uncleaved and cleaved CDCP1 according to Example 3, and an IP-blot (bottom) of a pull-down experiment using IgG 4A06 according to Example 3. [Figure 2C] FIG. 2C shows a schematic diagram of the proteolytic sites of CDCP1 identified according to Example 3. [Figure 2D] FIG. 2D shows CDCP1 peptides identified by IP-MS of the PDAC cell line PL5 according to Example 3. [Figure 2E] FIG. 2E shows CDCP1 peptides identified by IP-MS of the PDAC cell line PL45 according to Example 3. [Figure 2F] FIG. 2F shows CDCP1 peptides identified by IP-MS of HPAC cell lines according to Example 3. [Figure 3A] FIG. 3A outlines the two-plasmid co-transfection strategy for generating truncated CDCP1 ectodomains according to Example 4. [Figure 3B] Figure 3B shows an image of an SDS-PAGE gel of the fl-CDCP1 and c-CDCP1 (cleavage 1, cleavage 2, cleavage 3) ectodomains from Example 4. Note that the NTFs are heavily glycosylated and run as smeared bands on the gel. [Figure 3C] FIG. 3C shows a graphical representation of the results obtained by the BLI assay according to Example 4. [Figure 3D] FIG. 3D shows a graphical representation of the results obtained by differential scanning fluorimetry (DSF) of the fl-CDCP1 and c-CDCP1 (cleavage 1, cleavage 2, cleavage 3) ectodomains according to Example 4. [Figure 3E] FIG. 3E shows the circular dichroism (CD) spectra of fl-CDCP1 and c-CDCP1 according to Example 4. [Figure 3F] FIG. 3F shows the SEC-SAXS P(r) plots of fl-CDCP1 and c-CDCP1 ectodomains according to Example 4. [Figure 3G] FIG. 3G shows SEC-MALS traces of fl-CDCP1 and c-CDCP1 ectodomains according to Example 4. [Figure 3H] FIG. 3H shows a schematic diagram of the two-plasmid co-transfection strategy for generating truncated CDCP1 ectodomain as an Fc fusion according to Example 4. [Figure 3I] FIG. 3I shows an image of an SDS-PAGE gel of fl-CDCP1-Fc and c-CDCP1-Fc (cleavage sites 1, 2, and 3) according to Example 4. [Figure 3J] FIG. 3J shows a graphical representation of the results obtained by the BLI assay according to Example 4. [Figure 3K] FIG. 3K shows the SEC traces of fl-CDCP1-Fc and c-CDCP1-Fc (cleavage sites 1, 2, and 3) according to Example 4. [Figure 3L] FIG. 3L shows SEC traces of fl-CDCP1 and c-CDCP1 without the Fc domain (cleavage sites 1, 2, and 3). [Figure 3M] FIG. 3M shows a graphical representation of the SAXS profiles of the uncleaved and cleaved CDCP1 ectodomain according to Example 4. [Figure 3N] FIG. 3N shows a graphical representation of the normalized Kratsky plot of the uncleaved and cleaved CDCP1 ectodomains according to Example 4. [Figure 4A] FIG. 4A shows a schematic diagram of the strategy for generating stably transduced HEK293T cell lines expressing uncleaved or truncated CDCP1 according to Example 5. [Figure 4B] FIG. 4B shows a graphical representation of the flow cytometry results of binding of IgG 4A06 to HEK293T fl-CDCP1 and HEK293T c-CDCP1 cell lines according to Example 5. [Figure 4C] FIG. 4C shows images of Western blots of CDCP1, CDCP1 phosphorylation, and phosphorylation of intracellular proteins associated with CDCP1 signaling according to Examples 5 and 6. [Figure 4D] Figure 4D shows a graphical representation of the results of a cell adhesion assay comparing HEK239T fl-CDCP1, HEK293T c-CDCP1, and HEK239T wild-type cells performed according to Example 6. Note: **p=0.0016, ****p<0.0001, ns=not significant p>0.05 (unpaired t-test). [Figure 4E] FIG. 4E shows a graphical representation of the results of a cell adhesion assay of HEK293T cells expressing fl-CDCP1 according to Example 6. [Figure 4F] Figure 4F shows a graphical representation of the results of a cell adhesion assay of HEK293T cells expressing c-CDCP1 mutants according to Example 6. Note: Individual data points are shown, and bars indicate means. **p=0.003, ****p<0.0001, ns=not significant, p>0.05. [Figure 4G]Figure 4G shows a graphical representation of the results of a cell proliferation assay, as measured by MTT, of HEK293T cells expressing HEK293T WT, fl-CDCP1, and c-CDCP1, according to Example 6. Data were collected in triplicate, and the mean and standard deviation are shown. [Figure 4H] Figure 4H shows a graphical representation of the results of a cell proliferation assay, measured by MTT, of HEK293T cells expressing the fl-CDCP1 mutant according to Example 6. Data were collected in triplicate, and the mean and standard deviation are shown. [Figure 4I] Figure 4I shows a graphical representation of the results of a cell proliferation assay, measured by MTT, of HEK293T cells expressing c-CDCP1 mutants according to Example 6. Data were collected in triplicate, and the mean and standard deviation are shown. [Figure 5A] Figures 5A-5H show schematics and results relating to the generation of an antibody specific for truncated CDCP1 and in vitro and in vivo studies of this antibody according to Examples 7 and 8. Figure 5A shows a schematic of the differential phage selection strategy for identifying truncated CDCP1-specific binders according to Example 7. [Figure 5B] FIG. 5B shows a graphical representation of the results obtained by the BLI assay according to Example 7. [Figure 5C] FIG. 5C shows a negative stain EM 3D reconstruction of the c-CDCP1 (cleavage 3) ectodomain bound to Fab CL03 and nanobody according to Example 7. [Figure 5D] FIG. 5D shows immunofluorescence images of Alexa Fluor-488 labeled IgG CL03 on HPAC, PL5, and HPNE cells according to Example 8. [Figure 5E] Figure 5E shows a graphical representation of flow cytometry results relating to a panel of PDAC cells according to Example 8. Note: n=3, data represent mean and standard deviation. [Figure 5F]Figure 5F shows a schematic diagram of an antibody drug conjugate (ADC) cell killing assay (top) and a graphical representation of the dose-dependent ADC-mediated cell killing assay (bottom), performed according to Example 8. Note: **p=0.004, ***p=0.0018, unpaired T-test. [Figure 5G] Figure 5G shows a schematic diagram of the bispecific T cell engager (BiTE)-mediated T cell activation assay (left), a graphical representation of the dose-dependent activation of NFAT-GFP reporter Jurkat cells (center), and a graphical representation of BiTE CL03 (1 nM) activation of NFAT-GFP reporter T cells (right), according to Example 8. ***p<0.001, unpaired T-test. [Figure 5H] Figure 5H shows a graphical representation of the results obtained by in vivo positron emission tomography (PET) imaging of 89Zr-labeled IgG CL03 in PDAC xenograft mice bearing HPAC or PL5 tumors according to Example 8. Note: *p=0.0487, unpaired T-test, n=5 mice per cohort. [Figure 5I] FIG. 5I shows an image of phage eluted from the fourth round of phage selection (identification of truncated CDCP1-specific Fab by phage selection) according to Example 7. [Figure 5J] FIG. 5J shows a graphical representation of the results obtained by the BLI assay according to Example 7. [Figure 5K] FIG. 5K shows an image of an SDS-PAGE gel of fl-CDCP1 ectodomain treated with 0.5 μg of plasmin according to Example 7. [Figure 5L] FIG. 5L shows a graphical representation of the results obtained by a BLI assay performed according to Example 7. [Figure 5M] FIG. 5M shows the SEC trace of CDCP1 treated with plasmin according to Example 7. [Figure 5N] FIG. 5N shows a graphical representation of flow cytometry results of HPAC cells treated with plasmin according to Example 8. [Figure 5O]FIG. 5O shows a graphical representation of flow cytometry results of PL5 cells treated with plasmin according to Example 8. [Figure 6A] FIG. 6A shows a schematic diagram of NTF-Fc immobilization on a streptavidin (SA) biosensor via a C-terminal biotinylated Avi-tag on the Fc domain according to Example 7 (left) and further shows a graphical representation of the results obtained by BLI assay (right). [Figure 6B] FIG. 6B shows an overview of the immobilization scheme (top) and a graphical representation of the results obtained by the BLI assay (bottom) according to Example 7. [Figure 6C] FIG. 6C shows an overview of the immobilization scheme (top) and a graphical representation of the multipoint BLI assay (middle and bottom) according to Example 7. [Figure 6D] FIG. 6D shows a schematic diagram of the immobilization scheme (left) and a graphical representation of the results obtained by the BLI assay (right), according to Example 7. [Figure 6E] FIG. 6E outlines a proposed model for the binding of CL03 to truncated CDCP1 according to Example 7. [Figure 7A] FIG. 7A shows a graphical representation of the results obtained with a BLI assay measuring the species cross-reactivity of IgG CL03 according to Example 9. [Figure 7B] FIG. 7B shows a graphical representation of the results obtained with a BLI assay measuring the species cross-reactivity of IgG CL03 according to Example 9. [Figure 8A] FIG. 8A shows a schematic diagram of the two cleavage sites of truncated mouse CDCP1 according to Example 9. [Figure 8B] FIG. 8B shows an image of an SDS-PAGE gel of mouse CDCP1 antigens: fl-CDCP1-Fc, c-CDCP1-Fc (cleavage 1), c-CDCP1-Fc (cleavage 2) according to Example 9. [Figure 8C] FIG. 8C shows SEC traces of mouse CDCP1 antigens: fl-CDCP1-Fc, c-CDCP1-Fc (cleavage 1), c-CDCP1-Fc (cleavage 2) according to Example 9. [Figure 8D] FIG. 8D shows a graphical representation of the results obtained by the BLI assay according to Example 9. [Figure 8E] Figure 8E shows the binding of IgG58 to Fc1245 c-CDCP1 and Fc1245 WT cells as measured by flow cytometry, according to Example 9. Note: n=3, error bars indicate standard deviation. [Figure 8F] Figure 8F shows dose-dependent activation (% Jurkat activation) of NFAT-GFP reporter Jurkat cells by IgG12 reformatted into BiTE in the presence of Jurkat cells alone, or Fc1245 c-CDCP1 or Fc1245 WT cells, according to Example 9. Note: n=2, error bars indicate standard deviation. [Figure 8G] Figure 8G shows that dose-dependent ADC-mediated cell killing by secondary antibodies conjugated to IgG12 and MMAF was observed in Fc1245 c-CDCP1 or Fc1245 WT cells, according to Example 9. Note: n = 2, error bars represent standard deviation, **p = 0.0037, unpaired T-test. [Figure 9A] 9A-9G show a schematic diagram and associated results of a study of murine truncated CDCP1-specific antibody IgG 58 according to Example 9. FIG. 9A shows a graphical representation of the results obtained by the BLI assay according to Example 9. [Figure 9B] Figure 9B shows a graphical representation of flow cytometry results from Example 9. Note: n=3, error bars indicate standard deviation. [Figure 9C] Figure 9C shows a graphical representation of dose-dependent activation of NFAT-GFP reporter Jurkat cells by Ab58 reformatted into BiTE, according to Example 9. Note: n=2, error bars indicate standard deviation, ***p=0.005, unpaired T-test. [Figure 9D] Figure 9D shows a graphical representation of the results of dose-dependent ADC-mediated cell killing according to Example 9. Note: n=2, error bars represent standard deviation, **p=0.002, unpaired T-test. [Figure 9E] FIG. 9E shows a representation of the results of in vivo positron emission tomography (PET) imaging of 89Zr-labeled IgG58 in syngeneic mice bearing Fc1245-cCDCP1 or Fc1245-WT tumors according to Example 9. [Figure 9F] Figure 9F shows the biodistribution of 89Zr-IgG58 and 89Zr-IgG12 in mice bearing subcutaneous Fc1245 c-CDCP1 tumors, according to Example 9. Note: Mice (n=5 per arm), and **p=0.003, ***p=0.0002, ****p<0.0001, unpaired T-test. [Figure 9G] Figure 9G shows an ADC toxicity assay in non-tumor-bearing mice dosed with either IgG12-monomethylauristatin F (MMAF) or IgG58-MMAF at 5, 10, or 15 mg / kg, according to Example 9. Note: Mice (n=5 per arm), Dose 1 (day 0), Dose 2 (day 7), Dose 3 (day 14), (p=0.0002, ANOVA), and Tukey's multiple comparisons test, 15 mg / kg dose (***p=0.0068) and 10 mg / kg dose (**p=0.0067). [Figure 10] FIG. 10 shows a table of in vitro binding affinities of Fab CL03 and IgG CL03 to uncleaved and cleaved CDCP1 according to Example 7. [Figure 11] FIG. 11 shows a table of binding affinities of mouse CDCP1 antibodies to cleaved and uncleaved forms of mCDCP1 measured according to Example 9. [Figure 12A] Figure 12A shows negative stain EM 3D reconstructions of truncated CDCP1 binding to 4A06 Fab. (Left) 2D class average of c-CDCP1(cleavage 3) + 4A06 Fab in the absence and presence of VHH single domain antibodies. (Right) Different views of the 3D negative stain EM maps of c-CDCP1(cleavage 3) + 4A06 Fab + VHH. The crystal structure of the Fab with the VHH domain was fitted to the 3D negative stain EM map. [Figure 12B]FIG. 12B shows an illustrative microscopic image showing negatively stained c-CDCP1 (cleavage 3)+CL03 Fab+VHH particles. [Figure 12C] FIG. 12C shows the Fourier shell correlation plot used to determine the 25 Å model resolution of c-CDCP1(cleavage 3)+CL03 Fab+VHH obtained with the 0.143 criterion. [Figure 12D] FIG. 12D shows an illustrative microscopic image showing negatively stained c-CDCP1 (cleavage 3)+4A06 Fab+VHH particles. [Figure 12E] FIG. 12E shows the Fourier shell correlation plot used to determine the 23 Å model resolution of c-CDCP1(cleavage 3)+4A06 Fab+VHH obtained with the 0.143 criterion. [Figure 13] 13 shows a diagrammatic representation of an ELISA assay assessing binding of CL03 to fl-CDCP1, c-CDCP1 cleavage site 1, c-CDCP1 cleavage site 2, c-CDCP1 cleavage site 3, His-TEV-CUB1, or His-CUB1 according to Example 7. Circles represent fl-CDCP1, squares represent c-CDCP1 cleavage site 1, up-pointing triangles represent c-CDCP1 cleavage site 2, down-pointing triangles represent c-CDCP1 cleavage site 3, diamonds represent His-TEV-CUB1, and bold circles represent His-CUB1. [Figure 14A] 14A shows a diagrammatic representation of a competition assay measuring the ability of CUB1 NTF to compete for binding with CL03 on CDCP1-positive cells according to Example 8. Circles represent 100 nM IgG CL03, squares represent 50 nM IgG CL03, and triangles represent 0 nM IgG CL03. [Figure 14B] FIG. 14B shows a diagrammatic representation of a competition assay measuring the ability of CUB1 NTF to compete for binding with CL03 on CDCP1-positive cells according to Example 8. [Figure 15A]Figure 15A shows a graphical representation of tumor volumes in Fc1245 c-CDCP1 tumor-bearing mice injected with either PBS (control) or a single injection of 400 uCi of 177Lu-labeled IgG58 (test) according to Example 10 (N=5 for both control and test groups). The arrow indicates the time point when all mice in the PBS (control) group were euthanized due to ulcerated tumors. The solid line indicates the two data points used for the unpaired t-test. ***p=0.0001, unpaired T-test. [Figure 15B] Figure 15B shows a graphical representation of the body weight of Fc1245 c-CDCP1 tumor-bearing mice injected with either PBS (control) or a single injection of 400 uCi of 177Lu-labeled IgG58 (test) according to Example 10 (N = 5 for both control and test groups). [Figure 15C] Figure 15C shows a graphical representation of the survival probability of Fc1245 c-CDCP1 tumor-bearing mice injected with either PBS (control) or a single injection of 400 uCi of 177Lu-labeled IgG58 (test) according to Example 10 (N = 5 for both control and test groups). [Figure 16A] FIG. 16A shows a graphical representation of the results obtained by a BLI assay measuring the binding affinity of each of the antibodies designated IgG87, IgG89, IgG94, IgG97, IgG101 (CL03 IgG H1-NtoD H3-MtoA), and IgG102 to c-CDCP1-Fc (cleavage 2) according to Example 7. [Figure 16B] FIG. 16B shows SEC traces of antibodies designated IgG87, IgG89, IgG94, IgG97, IgG101 (CL03 IgG H1-NtoD H3-MtoA), and IgG102 according to Example 7. DETAILED DESCRIPTION OF THE INVENTION

[0089] The present disclosure relates to antibodies and antigen-binding fragments thereof that specifically bind to truncated CDCP1 (human or mouse), and that preferentially bind to truncated CDCP1. In some embodiments, the antibodies and antigen-binding fragments thereof disclosed herein do not bind to full-length human CDCP1 at detectable levels.

[0090] Other aspects of the present disclosure relate to methods of treating a subject in need thereof, comprising administering to the subject an antibody, bispecific antibody, multispecific antibody, or antigen-binding fragment thereof that specifically binds to a truncated form of human CDCP1, wherein the antibody or antigen-binding fragment does not bind to full-length human CDCP1. In some aspects, the subject has cancer, and the antibody, bispecific antibody, multispecific antibody, or antigen-binding fragment thereof treats the cancer in the subject.

[0091] I. Terminology In order that the description herein may be more readily understood, certain terms are first defined. Further definitions are set forth throughout the detailed description.

[0092] It should be noted that the term "a" or "an" entity refers to one or more of that entity; for example, "a nucleotide sequence" is understood to refer to one or more nucleotide sequences. Thus, the terms "a" (or "an"), "one or more," and "at least one" can be used interchangeably herein.

[0093] Furthermore, when used herein, "and / or" shall be construed as a specific disclosure that each of the two specified features or components may or may not involve one another. Thus, when the term "and / or" is used herein in phrases such as "A and / or B," it is intended to include "A and B," "A or B," "A (alone)," and "B (alone)." Similarly, when the term "and / or" is used in phrases such as "A, B, and / or C," it is intended to encompass each of the following embodiments: A, B, and C; A, B, or C; A or C; A or B; B, or C; A and C; A and B; B, and C; A (alone); B (alone); and C (alone).

[0094] Where embodiments are described herein using the word "comprising," it is understood that similar embodiments separately described using the terms "consisting of" and / or "consisting essentially of" are also provided.

[0095] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. For example, see the Concise Dictionary of Biomedicine and Molecular Biology, Juo, Pei-Show, 2nd ed., 2002, CRC Press; The Dictionary of Cell and Molecular Biology, 3rd ed., 1999, Academic Press; and the Oxford Dictionary of Biochemistry And Molecular Biology, Revised, 2000, Oxford University Press, provide one of skill in the art with a general dictionary for many of the terms used in this disclosure.

[0096] Units, prefixes, and symbols are shown in the format accepted by the International System of Units (SI). Numerical ranges are inclusive of the numbers defining the range. Unless otherwise indicated, nucleotide sequences are written left to right in 5' to 3' orientation. Amino acid sequences are written left to right in amino to carboxy orientation. The headings provided herein are not limiting of the various aspects of the disclosure, which may be obtained by reference to the specification as a whole. Accordingly, the terms defined immediately below are more fully defined by reference to the specification as a whole.

[0097] The term "about" is used herein to mean approximately, roughly, around, around, or within a range thereof. When the term "about" is used in conjunction with a numerical range, the term modifies that range by extending the boundaries above and below the stated numerical values. In general, the term "about" can modify a numerical value above or below the stated value, for example, by 10 percent above or below (higher or lower).

[0098] As used herein, the term "CDCP1" or "CUB domain-containing protein 1" or "complement C1r / C1s, Uegf, Bmp1 (CUB) domain-containing protein 1" is a 135 kDa heavily glycosylated single-pass transmembrane protein.

[0099] As used herein, the term "truncated CDCP1" refers to (i) endogenous truncated CDCP1 on the surface of cells and tissues (e.g., cancer cells) generated by proteolysis with a protease, and (ii) recombinantly produced truncated CDCP1. In some embodiments, truncated CDCP1 (e.g., truncated human CDCP1) is generated from full-length CDCP1 (e.g., full-length human CDCP1) by proteolytic cleavage between the CUB1 ectodomain and the CUB2 ectodomain. In some embodiments, truncated CDCP1 comprises a membrane-associated complex. In some embodiments, the membrane-associated complex comprises a truncated CUB1 ectodomain associated with a membrane-retaining fragment of CDCP1. In some embodiments, the membrane-retaining fragment of CDCP1 comprises a truncated CUB2 ectodomain associated with a non-cleaved CUB3 domain, and the truncated CUB2 ectodomain is formed by cleavage between the CUB1 and CUB2 linkers. In some embodiments, the membrane-bound complex comprises an N-terminal fragment of the CUB1 ectodomain and a C-terminal fragment of the CUB2 / CUB3 ectodomain. In some embodiments, a protease (e.g., a carboxypeptidase) can trim the N- or C-terminal fragment of truncated CDCP1 (e.g., truncated human CDCP1).

[0100] In some embodiments, the truncated human CDCP1 is generated by truncating at residues K365, R368, and / or K369 of SEQ ID NO:273.

[0101] In some embodiments, the truncated CDCP1 comprises a first cleavage domain and a second cleavage domain, wherein the first cleavage domain and the second cleavage domain are not linked.

[0102] As used herein, the term "first truncated domain" refers to the CUB1 ectodomain of human CDCP1 consisting of the amino acid sequence set forth in SEQ ID NOs: 63, 68, and 74.

[0103] As used herein, the term "second truncated domain" refers to the CUB2 / CUB3 ectodomain, transmembrane domain (TM), and intracellular domain (ICD) of human CDCP1 consisting of the amino acid sequences set forth in SEQ ID NOs: 64, 70, and 77.

[0104] In some embodiments, the truncated CDCP1 (e.g., truncated human CDCP1) is produced by (a) culturing a host cell containing a first polynucleotide encoding a truncated CUB1 ectodomain and a second polynucleotide encoding a CUB2 / CUB3 ectodomain, and (b) isolating the truncated CDCP1 (e.g., truncated human CDCP1). In some embodiments, the second polynucleotide encoding the CUB2 / CUB3 ectodomain comprises a transmembrane domain (TM) and an intracellular domain (ICD).

[0105] The terms "CDCP1" and "truncated CDCP1" include any mutant or isoform of CDCP1 and truncated CDCP1 that is naturally expressed by cells, including, but not limited to, tumor cells. Thus, the antibodies described herein may cross-react with truncated CDCP1 from species other than human (e.g., cynomolgus monkey CDCP1). Alternatively, the antibodies may be specific for human truncated CDCP1 and do not exhibit any cross-reactivity with other species. CDCP1, truncated CDCP1, or any mutant and isoform thereof may be isolated from cells or tissues that naturally express them, or may be recombinantly produced using techniques well known in the art and / or described herein.

[0106] Human CUB domain-containing protein 1 (CDCP1) (UniProt identification number Q9H5V8-1, SEQ ID NO: 273) is an 836-amino acid type I single-pass transmembrane protein with three CUB1 domains in its ectodomain. The intracellular region contains multiple tyrosine phosphorylation motifs. Extracellular proteases cleave CDCP1 between the CUB1 and CUB2 domains, resulting in its activation, phosphorylation of intracellular tyrosine residues by Src, and initiation of downstream signaling pathways through Akt. Truncated CDCP1 can also form complexes with other important membrane proteins, such as integrins, to initiate complex-mediated signaling.

[0107] At least two additional isoforms of human CDCP1 have been identified. Isoform 2 (UniProt Identification Number Q9H5V8-2, SEQ ID NO: 274) consists of 649 amino acids. Isoform 3 (UniProt Identification Number Q9H5V8-3, SEQ ID NO: 275) consists of 343 amino acids. Human CDCP1 isoform 3 lacks amino acid residues 344-836 and has the following differences (NK to SE) at amino acid residues 342-343 compared to the amino acid sequence of human CDCP1 (UniProt Identification Number Q9H5V8-1, SEQ ID NO: 273):

[0108] The amino acid sequences of the three known human CDCP1 isoforms are shown below. (A) Human CDCP1 (SEQ ID NO: 273): [ka] (SEQ ID NO: 273)

[0109] The signal sequence of human CDCP1 corresponds to amino acids 1 to 29 (underlined). Thus, the mature isoform of human CDCP1 isoform 1 consists of amino acids 30 to 836.

[0110] The extracellular domain of mature human CDCP1 consists of amino acids 30 to 836 of SEQ ID NO: 273, and has the amino acid sequence: FEIALPRESNITVLIKLGTPTLLAKPCYIVI SKRHITMLSIKSGERIVFTFSCQSPENHFVIEIQKNIDCMSGPCPFGEVQLQPSTSLLPT LNRTFIWDVKAHKSIGLELQFSIPRLRQIGPGESCPDGVTHSISGRIDATVVRIGTFCSN GTVSRIKMQEGVKMALHLPWFHPRNVSGFSIANRSSIKRLCIIESVFEGEGSATLMSANY PEGFPEDELMTWQFVVPAHLRASVSFLNFNLSNCERKEERVEYYIPGSTTNPEVFKLEDK QPGNMAGNFNLSLQGCDQDAQSPGILRLQFQVLVQHPQNESNKIYVVDLSNERAMSLTIE PRPVKQSRKFVPGCFVCLESRTCSSNLTLTSGSKHKISFLCDDLTRLWMNVEKTISCTDH RYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSF SYLVASAIPSQDLYFGSFCPGGSIKQIQVKQNISVTLRTFAPSFQQEASRQGLTVSFIPY FKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFFKERSGVVCQ TGRAFMIIQEQRTRAEEIFSLDEDVLPKPSFHHHSFWVNISNCSPTSGKQLDLLFSVTLT PRTVDLTVILIAAVGGGVLLLSALGLIICCVKKKKKKTNKGPAVGIYNDNINTEMPRQPK KFQKGRKDNDSHVYAVIEDTMVYGHLLQDSSGSFLQPEVDTYRPFQGTMGVCPPSPPTIC SRAPTAKLATEEPPPPRSPPESESEPYTFSHPNGDVSSKDTDPLLNTQEPMEPAE (SEQ ID NO: 276) It has. (B) Human CDCP1 isoform 2 (UniProt identification number Q9H5V8-2, SEQ ID NO: 274): MQEGVKMALHLPWFHPRNVSGFSIANRSSIKRLCIIESVFEGEGSATLMSANY PEGFPEDELMTWQFVVPAHLRASVSFLNFNLSNCERKEERVEYYIPGSTTNPEVFKLEDK QPGNMAGNFNLSLQGCDQDAQSPGILRLQFQVLVQHPQNESNKIYVVDLSNERAMSLTIE PRPVKQSRKFVPGCFVCLESRTCSSNLTLTSGSKHKISFLCDDLLTRLWMNVEKTISCTDH RYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSF SYLVASAIPSQDLYFGSFCPGGSIKQIQVKQNISVTLRTFAPSFQQEASRQGLTVSFIPY FKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFKERSGVVCQ TGRAFMIIQEQRTRAEEIFSLDEDVLPKPSFHHHSFWVNISNCSPTSGKQLDLLFSVTLT PRTVDLTVILIAAVGGGVLLLSALGLIICCVKKKKKKTNKGPAVGIYNDNINTEMPRQPK KFQKGRKDNDSHVYAVIEDTMVYGHLLQDSSGSFLQPEVDTYRPFQGTMGVCPPSPPTIC SRAPTAKLATEEPPPRSPPESESEPYTFSHPNNGDVSSKDTDIPLLNTQEPMEPAE (SEQ ID NO: 274) (C) Human CDCP1 isoform 3 (UniProt identification number Q9H5V8-3, SEQ ID NO: 275): [ka] (SEQ ID NO: 275)

[0111] Amino acid sequence of c-CDCP1 cleavage site 1 N-terminal fragment (NTF) of the extracellular domain FEIALPRESNITVLIKLGTPTLLAKPCYIVISKRHITMLSIKSGERIVFTFSCQSPENHFVIEIQKNIDCMSGPCPFGEVQLQPSTSLLPTLNRTFIWDVKAHKSIGLELQFSIPRLRQIGPGESCPDGVTHSISGRIDATVVRIGTFCSNGTVSRIKMQEGVKMALHLPWFHPRNVSGFSIANRSSIKRLCIIESVFEGEGSATLMSANYPEGFPEDELMTWQFVVPAHLRASVSFLNFNLSNCERKEERVEYYIPGSTTNPEVFKLEDKQPGNMAGNFNLSLQGCDQDAQSPGILRLQFQVLVQHPQNESNKIYVVDLSNERAMSLTIEPRPVK (SEQ ID NO: 63)

[0112] Amino acid sequence of the c-CDCP1 cleavage site 1 C-terminal fragment (CTF) of the extracellular domain, including the transmembrane domain (TM) and intracellular domain (ICD) QSRKFVPGCFVCLESRTCSSNLTLTSGSKHKISFLCDLTRLWMNVEKTISCTDHRYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSFSYLV ASAIPSQDLYFGSFCPGGSIKQIQVKQNISVTLRTFAPSFQQEASRQGLTVSFIPYFKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFKERSGVVCQTGRA FMIIQEQRTRAEEIFSLDEDVLPKPSFHHHSFWVNISNCSPTSGKQLDLLFSVTLTPRTVDLTVILIAAVGGGVLLLSALGLIICCVKKKKKKTNKGPAVGIYNDNINTEMPRQPKKFQKGRKDNDSHVYAVIEDTMVYGHLLQDSSGSFLQPEVDTYRPFQGTMGVCPPSPPTICSRAPTAKLATEEPPPRSPPESESEPYTFSHPNNGDVSSKDTDIPLLNTQEPMEPAE (SEQ ID NO: 64)

[0113] Amino acid sequence of the c-CDCP1 cleavage site 1 C-terminal fragment (CTF) of the extracellular domain, without the transmembrane domain (TM) and intracellular domain (ICD) amino acid sequences QSRKFVPGCFVCLESRTCSSNLTLTSGSKHKISFLCDDLTRLWMNVEKTISCTDHRYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSFSYLVASAIPSQDLYFGSFCPGGSIKQIQVKQNISVTLRTFAPSFQQEASRQGLTVSFIPYFKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFFKERSGVVCQTGRAFMIIQEQRTRAEEIFSLDEDVLPKPSFHHHSFWVNISNCSPTSGKQLDLLFSVTLTPRTVDLT (SEQ ID NO: 66)

[0114] Amino acid sequence of the N-terminal fragment of c-CDCP1 cleavage site 2 of the extracellular domain FEIALPRESNITVLIKLGTPTLLAKPCYIVISKRHITMLSIKSGERIVFTFSCQSPENHFVIEIQKNIDCMSGPCPFGEVQLQPSTSLLPTLNRTFIWDVKAHKSIGLELQFSIPRLRQIGPGESCPDGVTHSISGRIDATVVRIGTFCSNGTVSRIKMQEGVKMALHLPWFHPRNVSGFSIANRSSIKRLCIIESVFEGEGSATLMSANYPEGFPEDELMTWQFVVPAHLRASVSFLNFNLSNCERKEERVEYYIPGSTTNPEVFKLEDKQPGNMAGNFNLSLQGCDQDAQSPGILRLQFQVLVQHPQNESNKIYVVDLSNERAMSLTIEPRPVKQSR (SEQ ID NO: 68)

[0115] Amino acid sequence of the c-CDCP1 cleavage site 2 C-terminal fragment of the extracellular domain, including the transmembrane domain (TM) and intracellular domain (ICD) KFVPGCFVCLESRTCSSNLTLTSGSKHKISFLCDLTRLWMNVEKTISCTDHRYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSFSYLVASA IPSQDLYFGSFCPGGSIKQIQVKQNISVTLRTFAPSFQQEASRQGLTVSFIPYFKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFKERSGVVCQTGRAFM IIQEQRTRAEEIFSLDEDVLPKPSFHHHSFWVNISNCSPTSGKQLDLLFSVTLTPRTVDLTVILIAAVGGGVLLLSALGLIICCVKKKKKKTNKGPAVGIYNDNINTEMPRQPKKFQKGRKDNDSHVYAVIEDTMVYGHLLQDSSGSFLQPEVDTYRPFQGTMGVCPPSPPTICSRAPTAKLATEEPPPRSPPESESEPYTFSHPNNGDVSSKDTDIPLLNTQEPMEPAE (SEQ ID NO: 70)

[0116] Amino acid sequence of the c-CDCP1 cleavage site 2 C-terminal fragment of the extracellular domain, without the transmembrane domain (TM) and intracellular domain (ICD) KFVPGCFVCLESRTCSSNLTLTSGSKHKISFLCDDLTRLWMNVEKTISCTDHRYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSFSYLVASAIPSQDLYFGSFCPGGSIKQIQVKQNISVTLRTFAPSFQQEASRQGLTVSFIPYFKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFFKERSGVVCQTGRAFMIIQEQRTRAEEIFSLDEDVLPKPSFHHHSFWVNISNCSPTSGKQLDLLFSVTLTPRTVDLT (SEQ ID NO: 72)

[0117] Amino acid sequence of the N-terminal fragment of c-CDCP1 cleavage site 3 of the extracellular domain FEIALPRESNITVLIKLGTPTLLAKPCYIVISKRHITMLSIKSGERIVFTFSCQSPENHFVIEIQKNIDCMSGPCPFGEVQLQPSTSLLPTLNRTFIWDVKAHKSIGLELQFSIPRLRQIGPGESCPDGVTHSISGRIDATVVRIGTFCSNGTVSRIKMQEGVKMALHLPWFHPRNVSGFSIANRSSIKRLCIIESVFEGEGSATLMSANYPEGFPEDELMTWQFVVPAHLRASVSFLNFNLSNCERKEERVEYYIPGSTTNPEVFKLEDKQPGNMAGNFNLSLQGCDQDAQSPGILRLQFQVLVQHPQNESNKIYVVDLSNERAMSLTIEPRPVKQSRK (SEQ ID NO: 74)

[0118] Amino acid sequence of the c-CDCP1 cleavage site 3 C-terminal fragment of the extracellular domain, including the transmembrane domain (TM) and intracellular domain (ICD) FVPGCFVCLESRTCSSNLTLTSGSKHKISFLCDLTRLWMNVEKTISCTDHRYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSFSYLVASA IPSQDLYFGSFCPGGSIKQIQVKQNISVTLRTFAPSFQQEASRQGLTVSFIPYFKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFKERSGVVCQTGRAFM IIQEQRTRAEEIFSLDEDVLPKPSFHHHSFWVNISNCSPTSGKQLDLLFSVTLTPRTVDLTVILIAAVGGGVLLLSALGLIICCVKKKKKKTNKGPAVGIYNDNINTEMPRQPKKFQKGRKDNDSHVYAVIEDTMVYGHLLQDSSGSFLQPEVDTYRPFQGTMGVCPPSPPTICSRAPTAKLATEEPPPRSPPESESEPYTFSHPNNGDVSSKDTDIPLLNTQEPMEPAE (SEQ ID NO: 77)

[0119] Amino acid sequence of the c-CDCP1 cleavage site 3 C-terminal fragment of the extracellular domain, without the transmembrane domain (TM) and intracellular domain (ICD) FVPGCFVCLESRTCSSNLTLTSGSKHKISFLCDDLTRLWMNVEKTISCTDHRYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSFSYLVASAIPSQDLYFGSFCPGGSIKQIQVKQNISVTLRTFAPSFQQEASRQGLTVSFIPYFKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFFKERSGVVCQTGRAFMIIQEQRTRAEEIFSLDEDVLPKPSFHHHSFWVNISNCSPTSGKQLDLLFSVTLTPRTVDLT (SEQ ID NO: 78)

[0120] Mouse CDCP1 has the following amino acid sequence (including the signal sequence) (UniProt identification number Q5U462-1, SEQ ID NO: 277): MAHSACGFSVALLGALLLGTARLLRGTEASEIALPQRSGVTVSIKLGNPALPVKICYIVM SRQHITELIIRPGERKSFTFSCSNPEKHFVLKIEKNIDCMSGPCPFGEVHLQPSTSELPI LNRTFIWDVRAHKSIGLELQFATPRLRQIGPGESCADGVTHSISGHIDATEVRIGTFCSN GTVSRIKMQEGVKMALHLPWFHRRNVSGFSIANRSSIKRLCIIESVFEGEGSATLMSANY PGGFPEDELMTWQFVVPAHLRASVSFLNFNVSNCERKEERVEYYIPGSTTNPEVFRLEDK QPGNMAGNFNLSLQGCDQDAQSPGILRLQFQVLVQRPQDESNKTYMVDLSRERTMSLTIE PRPVKHGRRFVPGCFVCLESRTCSTNVTLTAGSIHKISFLCDDLTRLWVNVEKTLSCLDH RYCYRQSFKLQVPDYILQLPVQLHDFSWKLLVPKDKLSLMLVPGQKLQQHTQERPCNTSF GYHVTSTTPGQDLYFGSFCSGGSIEKIQVKQNSSVTLRAYAPSFQQEVSKQGLIVSYTPY FKEEGIFTVTPDTKNKVYLRSPNWDRGLPALSSVSWNISVPSNQVACLTVLKERSGLACQ SGRAFMIIQEQQSRAEEIFSLEEEVLPKPSFHHHSFWVNISNCSPMNGKQLDLLFWVTLT PRTVDLAVVIGAAGGGALLLFALVLIICFVKKKKKVDKGPAVGIYNGNVNTQMPQTQKFP KGRKDNDSHVYAVIEDTMVYGHLLQDSGGSFIQPEVDTYRPFQGPMGDCPPTPPPLFSRT PTAKFTAEELAPSSPPESESEPYTFSHPNKGEIGVRETDIPLLHTQGPVETEE (SEQ ID NO: 277) Includes.

[0121] Cynomolgus monkey CDCP1 has the following amino acid sequence (including the signal sequence) (UniProt identification number A0A2K5VLK2-1, SEQ ID NO: 278): MAGLNCGVTIALLGVLLLGAARLPRAAEAFEIALPRESNITVLIKLGTPTLLAKPCYIVI SKRHTTMLSIKPGERILFTFSCQSPENHFVIEIQKNIDCMSGPCPFGEVQLQPSTSLLPT LNRTFIWDVKAHKSIGLELQFSIPLLRQIGPGESCPGGVTYSISGRIDATVVRIGTFCSN GTVSRIKMQEGVKMALHLPWFHPRNVSGFSIANRSSIKRLCIIESVFEGEGSATLMSANY PEGFPEDELMTWQFVIPAHLRASVSFLNFNLSNCERKEERVEYYIPGSTTNPEVFKLEDK QPGNMAGNFNLSLQGCDQDAQNPGILRLQFQVLVQHPQNESNKIYVVDLSNERATSLTIE PRPVKQSRKFVPGCFVCLESRTCSTNLTLTSGSKHKISFLCDNLTRLWMNVEKNISCTDH RYCQRKSYSLQVPSDILHLPVELHDFSWKLLVPKDRLSLVLVPAQKLQQHTHEKPCNTSF SYLVASAIPSQDLYFGSFCPGGSIEQIQVKQNISVTLRTFAPSFRQEASRQGLTVSFIPY FKEEGVFTVTPDTKSKVYLRTPNWDRGLPSLTSVSWNISVPRDQVACLTFKERTGVVCQ TGRAFMIIQEQRTRAEEIFSLDEDALPKPRFHHHSFWVNISNCSPASGKQLDLLFWVTLT PRTVDLTVILITVVGGGAVLLSALGLIICCVKKKKKKTNKGPAVGVYNGNINTEMPRQPK KFQKGRKDNDSHVYAVIEDTMVYGHLLQDSGGSFLQPEVDTYRPFQGTMGVCPPSPPTIC SRAPTAKLAAEELPPCSPPESESEPYTFSHPNNGDINSKETDIPLLNTQEPVEPAE (SEQ ID NO: 278) Includes.

[0122] The term "antibody," in some embodiments, refers to a protein comprising at least two heavy (H) chains and two light (L) chains interconnected by disulfide bonds. Each heavy chain is composed of a heavy chain variable region (abbreviated herein as VH) and a heavy chain constant region (abbreviated herein as CH). As used herein, the term "bispecific antibody" refers to an antibody comprising at least two antigen-binding domains, i.e., at least two paratopes. Thus, in some embodiments, a bispecific antibody comprises at least two heavy chain variable regions (VH1 and VH2) and at least two light chain variable regions (VL1 and VL2). In some embodiments, the at least two heavy chain variable regions are the same or different. In some embodiments, the at least two light chain variable regions are the same or different. As used herein, a "multispecific antibody" refers to an antibody comprising at least three antigen-binding domains, i.e., at least three paratopes.

[0123] In some antibodies, such as naturally occurring IgG antibodies, the heavy chain constant region consists of a hinge and three domains, CH1, CH2, and CH3. In some antibodies, such as naturally occurring IgG antibodies, each light chain consists of a light chain variable region (abbreviated herein as VL) and a light chain constant region. The light chain constant region consists of one domain (abbreviated herein as CL). The VH and VL regions are called complementarity-determining regions (CDRs), which can be further subdivided into regions of hypervariability interspersed with more conserved regions called framework regions (FRs). Each VH and VL is composed of three CDRs and four FRs, arranged from the amino terminus to the carboxy terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4. The variable regions of the heavy and light chains contain the binding domains that interact with antigens. The constant region of an antibody may mediate the binding of the immunoglobulin to host tissues or factors, such as various cells of the immune system (e.g., effector cells) and the first component (Clq) of the classical complement system. The heavy chain may or may not have a C-terminal lysine. Unless otherwise specified herein, amino acids in the variable region are numbered using the Kabat numbering system, and amino acids in the constant region are numbered using the EU system.

[0124] "IgG antibodies," e.g., human IgG1, IgG2, IgG3, and IgG4 antibodies, as used herein, in some embodiments, have the structure of a naturally occurring IgG antibody, i.e., they have the same number of heavy and light chains and disulfide bonds as a naturally occurring IgG antibody of the same subclass. For example, an anti-human or mouse truncated CDCP1 IgG1, IgG2, IgG3, or IgG4 antibody consists of two heavy chains (HC) and two light chains (LC), and the two HCs and LCs are linked by the same number and positions of disulfide bridges as occur in naturally occurring IgG1, IgG2, IgG3, and IgG4 antibodies, respectively (unless the antibody has been mutated to modify the disulfide bridges).

[0125] Antibodies usually bind to their cognate antigens. -5 ~10 -11 The dissociation constant (K D ) specifically binds with high affinity as reflected by approximately 10 -4 Any K greater than M D As used herein, an antibody that "specifically binds" to an antigen is one that binds to the antigen and a substantially identical antigen in a specific manner. -7 M or less, 10 -8 M or less, 5×10 -9 M or less, or 10 -8 M to 10 -10 K between M and below D An antibody that specifically binds to a truncated human CDCP1 is an antibody that binds to the given antigen with high affinity, meaning that it has high affinity, but does not bind to unrelated antigens with high affinity. An antigen is "substantially identical" to a given antigen if it shows a high degree of sequence identity to the given antigen, for example, if it shows at least 80%, at least 90%, at least 95%, at least 97%, or at least 99% sequence identity to the sequence of the given antigen. For example, an antibody that specifically binds to truncated human CDCP1 will, in some embodiments, be cross-reactive with CDCP1 antigens from a particular primate species (e.g., cynomolgus monkey CDCP1) but may not cross-react with CDCP1 antigens from other species or with antigens other than CDCP1.

[0126] As used herein, the phrase "preferentially binds" or grammatically similar terms refers to the fact that an antibody or antigen-binding fragment thereof specifically binds to a first antigen (e.g., truncated CDCP1) more readily than to a second antigen (e.g., full-length CDCP1). Thus, an antibody that "preferentially binds" to a given antigen (e.g., truncated CDCP1) will more likely bind to that antigen than to a related antigen (e.g., full-length CDCP1), even if such an antibody may cross-react with the related antigen. In some embodiments, an antibody that preferentially binds to a first antigen (e.g., truncated CDCP1) does not bind to a second antigen (e.g., full-length CDCP1) at a detectable level. In some embodiments, an antibody or antigen-binding fragment disclosed herein binds to truncated CDCP1 at least 10-fold, at least 100-fold, or at least 1000-fold more tightly than to full-length CDCP1. Exemplary methods used to detect binding between an antibody and an antigen can be, but are not limited to, phase ELISA, biolayer interferometry analysis using an Octet instrument (e.g., ForteBio), and surface plasmon resonance (SPR) analysis.

[0127] Immunoglobulins can be derived from any of the well-known isotypes, including, but not limited to, IgA, secretory IgA, IgG, and IgM. The IgG isotype is divided into subclasses in certain species: IgG1, IgG2, IgG3, and IgG4 in humans, and IgG1, IgG2a, IgG2b, and IgG3 in mice. In some embodiments, the anti-human truncated CDCP1 antibodies described herein are of the IgG1 subtype. Immunoglobulins, such as IgG1, exist in several allotypes that differ from each other by at most two or three amino acids. "Antibody" includes, by way of example, both naturally occurring and non-naturally occurring antibodies, monoclonal and polyclonal antibodies, chimeric and humanized antibodies, human and non-human antibodies, and completely synthetic antibodies.

[0128] As used herein, the term "antigen-binding fragment" of an antibody refers to one or more fragments of an antibody that retain the ability to specifically bind to an antigen (e.g., truncated human CDCP1). It has been shown that the antigen-binding function of an antibody can be performed by fragments of a full-length antibody. Examples of binding fragments encompassed by the term "antigen-binding fragment" of an antibody, for example, an anti-human or mouse truncated CDCP1 antibody described herein, include: (i) V L , V H (ii) a Fab fragment (a fragment derived from papain cleavage) or a similar monovalent fragment consisting of the CL, CL, and CH1 domains; (iii) a F(ab')2 fragment (a fragment derived from pepsin cleavage) or a similar bivalent fragment comprising two Fab fragments linked by a disulfide bridge in the hinge region; H and an Fd fragment consisting of the CH1 domain, (iv) a V of one arm of an antibody L and V H Fv fragment consisting of domains, (v) V H (vi) dAb fragments consisting of a domain (Ward et al., (1989) Nature 341:544-546), (vi) an isolated complementarity-determining region (CDR), and (vii) a combination of two or more isolated CDRs, optionally connected by a synthetic linker. Furthermore, although the two domains of an Fv fragment, VL and VH, are encoded by separate genes, they can be connected using recombinant methods with a synthetic linker, allowing the VL and VH domain pair to be produced as a single protein chain forming a monovalent molecule (known as a single-chain Fv (scFv); see, e.g., Bird et al. (1988) Science 242:423-426; and Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85:5879-5883). Such single-chain antibodies are also intended to be encompassed within the term "antigen-binding fragment" of an antibody. These antibody fragments are obtained using conventional techniques known to those with skill in the art, and the fragments are screened for utility in the same manner as are intact antibodies. Antigen-binding fragments can be produced by recombinant DNA techniques or by enzymatic or chemical cleavage of intact immunoglobulins.

[0129] A "bispecific" or "bifunctional antibody" is an artificial hybrid antibody having two different heavy / light chain pairs and two different binding sites. Bispecific antibodies can be produced by a variety of methods, including fusion of hybridomas or linking of Fab' fragments. See, e.g., Songsivilai & Lachmann, Clin. Exp. Immunol. 79:315-321 (1990); Kostelny et al., J. Immunol. 148:1547-1553 (1992).

[0130] The term "monoclonal antibody," as used herein, refers to an antibody derived from a population of substantially homogeneous antibodies, i.e., the individual antibodies within the population are substantially similar and bind to the same epitope (e.g., the antibodies exhibit a single binding specificity and affinity), except for possible variations that may arise during the production of the monoclonal antibody, although such variations will generally be present in minor amounts. The modifier "monoclonal" indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies and is not to be construed as requiring production of the antibody by any particular method. The term "human monoclonal antibody" refers to an antibody derived from a substantially homogeneous population of antibodies that exhibits a single binding specificity and has variable and, optionally, constant regions derived from human germline immunoglobulin sequences. In some embodiments, human monoclonal antibodies are produced by hybridomas comprising B cells obtained from a transgenic non-human animal, e.g., a transgenic mouse having a genome comprising a human heavy chain transgene and a light chain transgene fused to an immortalized cell.

[0131] As used herein, the term "recombinant human antibody" includes all human antibodies prepared, expressed, generated, or isolated by recombinant means, such as (a) antibodies isolated from animals (e.g., mice) that are transgenic or transchromosomal for human immunoglobulin genes or hybridomas prepared therefrom, (b) antibodies isolated from host cells transformed to express the antibody, e.g., from transfectomas, (c) antibodies isolated from recombinant, combinatorial human antibody libraries, and (d) antibodies prepared, expressed, generated, or isolated by any other means, including splicing of human immunoglobulin gene sequences into other DNA sequences. Such recombinant human antibodies utilize specific human germline immunoglobulin sequences and contain variable and constant regions encoded by germline genes, but include subsequent rearrangements and mutations that occur, for example, during antibody maturation. As is known in the art (see, e.g., Lonberg (2005) Nature Biotech. 23(9):1117-1125), variable regions contain antigen-binding domains encoded by various genes that rearrange to form antibodies specific to foreign antigens. In addition to rearrangement, variable regions can be further modified by multiple single amino acid changes (also called somatic mutation or hypermutation) to increase the affinity of the antibody for the foreign antigen. The constant regions further change in response to the antigen (i.e., isotype switching). Thus, rearranged and somatically mutated nucleic acid molecules encoding light and heavy chain immunoglobulin polypeptides in response to the antigen may not have sequence identity with the original nucleic acid molecule, but instead will be substantially identical or similar (i.e., have at least 80% identity).

[0132] A "human" antibody (HuMAb) refers to an antibody having variable regions in which both the framework and CDR regions are derived from human germline immunoglobulin sequences. Furthermore, if the antibody contains a constant region, the constant region is also derived from a human germline immunoglobulin sequence. The anti-human truncated CDCP1 antibodies described herein may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo). However, as used herein, the term "human antibody" is not intended to include antibodies in which CDR sequences derived from the germline of another mammalian species, such as a mouse, have been grafted onto human framework sequences. The terms "human" antibody and "fully human" antibody are used interchangeably.

[0133] A "humanized" antibody refers to an antibody in which some, most, or all of the amino acids outside the CDR domains of a non-human antibody have been replaced with corresponding amino acids from a human immunoglobulin. In some embodiments of humanized forms of antibodies, some, most, or all of the amino acids outside the CDR domains have been replaced with amino acids from a human immunoglobulin, while some, most, or all of the amino acids within one or more CDR regions remain unchanged. Small additions, deletions, insertions, or substitutions or modifications of amino acids are permissible as long as they do not abrogate the antibody's ability to bind to a specific antigen. A "humanized" antibody retains antigen specificity similar to that of the original antibody.

[0134] "Chimeric antibody" refers to an antibody whose variable region is derived from one species and whose constant region is derived from another species, such as an antibody whose variable region is derived from a mouse antibody and whose constant region is derived from a human antibody.

[0135] As used herein, "isotype" refers to the antibody class (e.g., IgG1, IgG2, IgG3, IgG4, IgM, IgA1, IgA2, IgD and IgE antibodies) encoded by heavy chain constant region genes.

[0136] "Allotype" refers to naturally occurring variants within a particular isotype group, which variants differ by two or three amino acids (see, e.g., Jefferis et al. (2009) mAbs 1:1). The anti-human or mouse truncated CDCP1 antibodies described herein can be of any allotype. Antibodies referred to herein as "IgG1f," "IgG1.1f," or "IgG1.3f" isotypes are IgG1, effectorless IgG1.1, and effectorless IgG1.3 antibodies, respectively, of allotype "f," i.e., 214R, 356E, and 358M according to the Kabat EU index.

[0137] The phrases "antibody that recognizes an antigen" and "antibody specific for an antigen" are used herein interchangeably with the term "antibody that specifically binds to an antigen."

[0138] An "isolated antibody," as used herein, is intended to refer to an antibody that is substantially free of other proteins and cellular material.

[0139] As used herein, an antibody that "binds to truncated CDCP1" refers to an antibody that has an EC of about 25 μg / mL or less, about 23 μg / mL or less, about 20 μg / mL or less, about 15 μg / mL or less, about 10 μg / mL or less, about 5 μg / mL or less, about 3 μg / mL or less, about 2 μg / mL or less, about 1 μg / mL or less, about 0.5 μg / mL or less, about 0.45 μg / mL or less, about 0.4 μg / mL or less, about 0.35 μg / mL or less, or about 0.3 μg / mL or less in a binding assay using, for example, HEK293T cells transfected with truncated human or mouse CDCP1-expressing tumor cells, as determined by art-recognized methods, e.g., a FACS-based binding assay as described herein. 50The term "antibody" is intended to refer to an antibody that interacts with truncated CDCP1 (e.g., human and mouse truncated CDCP1) at a binding affinity of about 200 nM or less, about 175 nM or less, about 160 nM or less, about 150 nM or less, about 125 nM or less, about 110 nM or less, or about 100 nM or less. About 80nM or less, about 75nM or less, about 60nM or less, about 50nM or less, about 40nM or less, about 35nM or less, about 30nM or less, about 25nM or less, about 20nM or less, about 15nM or less, About 10nM or less, about 9nM or less, about 8nM or less, about 7nM or less, about 6nM or less, about 5nM or less, about 4nM or less, about 3nM or less, about 2nM or less, about 1.9nM or less, about 1.8nM or less Bottom, about 1.7nM or less, about 1.6nM or less, about 1.5nM or less, about 1.4nM or less, about 1.3nM or less, about 1.2nM or less, about 1.1nM or less, about 1.0nM or less, about 0.9nM EC of less than or equal to about 0.8nM, less than or equal to about 0.7nM, less than or equal to about 0.6nM, less than or equal to about 0.5nM, less than or equal to about 0.4nM, less than or equal to about 0.3nM, less than or equal to about 0.2nM, or less than or equal to about 0.1nM 50 In certain embodiments, the anti-cleaved CDCP1 antibodies, or antigen-binding fragments thereof, e.g., as described herein, have an EC of less than about 10 nM. 50 In certain embodiments, the anti-cleaved CDCP1 antibodies, or antigen-binding fragments thereof, e.g., as described herein, have an EC of less than about 5 nM. 50 In certain embodiments, the anti-cleaved CDCP1 antibodies, or antigen-binding fragments thereof, e.g., as described herein, have an EC of less than about 1.5 nM. 50 In certain embodiments, the anti-cleaved CDCP1 antibodies, or antigen-binding fragments thereof, e.g., as described herein, have an EC of about 1 nM or less. 50In certain embodiments, the anti-cleaved CDCP1 antibodies, or antigen-binding fragments thereof, e.g., as described herein, have an EC of about 0.5 nM or less. 50 In certain embodiments, the anti-cleaved CDCP1 antibodies, or antigen-binding fragments thereof, e.g., as described herein, have an EC of about 0.3 nM or less. 50 In certain embodiments, the anti-cleaved CDCP1 antibodies, or antigen-binding fragments thereof, e.g., as described herein, have an EC of about 0.2 nM or less. 50 and binds to truncated CDCP1 (human or mouse) expressed on HEK293T cells, for example.

[0140] As used herein, an antibody that "inhibits, prevents, or reduces shedding of cleaved CDCP1" by a cell, e.g., a tumor cell, is intended to refer to an antibody that inhibits, prevents, or reduces the release of cleaved CDCP1 from the surface of the cell. Without being bound by mechanism, for example, the anti-cleaved CDCP1 antibodies described herein, or antigen-binding fragments thereof disclosed herein, reduce the amount of cleaved CDCP1. In some embodiments, the antibody increases membrane-bound cleaved CDCP1 on the surface of the cell. In some embodiments, for example, the anti-truncated CDCP1 antibodies, or antigen-binding fragments thereof, described herein, enhance retention of surface truncated CDCP1 on cells transfected with human or mouse truncated CDCP1 to about 10 nM or less, about 5 nM or less, about 1 nM or less, about 0.85 nM or less, about 0.8 nM or less, about 0.75 nM or less, about 0.7 nM or less, about 0.65 nM or less, about 0.6 nM or less, about 0.55 nM or less, about 0.5 nM or less, about 0.45 nM or less, about 0.4 nM or less, about 0.35 nM or less, about 0.3 nM or less, about 0.25 nM or less, about 0.2 nM or less, about 0.15 nM or less, or about 0.1 nM or less of truncated human or mouse CDCP1 retention EC 50In certain embodiments, for example, an anti-human or mouse truncated CDCP1 antibody, or antigen-binding fragment thereof, described herein increases retention of truncated human or mouse CDCP1 on the surface of cells transfected with human truncated CDCP1 by at least about 1.2-fold, at least about 1.3-fold, at least about 1.4-fold, at least about 1.5-fold, at least about 1.6-fold, at least about 1.7-fold, at least about 1.8-fold, at least about 1.9-fold, at least about 2-fold, at least about 2.1-fold, at least about 2.2-fold, at least about 2.3-fold, at least about 2.4-fold, at least about 2.5-fold, at least about 2.75-fold, at least about 3-fold, at least about 3.5-fold, at least about 4-fold, at least about 4.5-fold, at least about 5-fold, at least about 7.5-fold, at least about 10-fold, or at least about 20-fold.

[0141] "Effector function" refers to the interaction of the Fc region of an antibody with an Fc receptor or ligand, or the resulting biochemical events. Exemplary "effector functions" include Clq binding, complement-dependent cytotoxicity (CDC), Fc receptor binding, FcγR-mediated effector functions such as ADCC and antibody-dependent cell-mediated phagocytosis (ADCP), and downregulation of cell surface receptors (e.g., B cell receptors; BCRs). Such effector functions generally require the Fc region to be combined with a binding domain (e.g., an antibody variable domain).

[0142] An "Fc receptor" or "FcR" is a receptor that binds to the Fc region of an immunoglobulin. FcRs that bind to IgG antibodies include receptors of the FcγR family, including allelic variants and alternatively spliced ​​forms of these receptors. The FcγR family consists of three activating (FcγRI, FcγRIII, and FcγRIV in mice; FcγRIA, FcγRIIA, and FcγRIIIA in humans) and one inhibitory (FcγRIIB) receptor. The various properties of human FcγRs are known in the art. Most innate effector cell types simultaneously express one or more activating FcγRs and inhibitory FcγRIIB, while natural killer (NK) cells selectively express one activating Fc receptor (FcγRIII in mice and FcγRIIIA in humans) but do not express inhibitory FcγRIIB in mice or humans. Human IgG1 binds to most human Fc receptors and is considered equivalent to mouse IgG2a with respect to the types of activating Fc receptors it binds.

[0143] The term "Fc region" (fragment crystallizable region) or "Fc domain" or "Fc" refers to the C-terminal region of an antibody heavy chain that mediates binding of the immunoglobulin to host tissues or factors, including binding to Fc receptors located on various cells of the immune system (e.g., effector cells) or the first component (C1q) of the classical complement system. Thus, the Fc region includes the constant region of an antibody, excluding the first constant region immunoglobulin domain (e.g., CH1 or CL). In IgG, IgA, and IgD antibody isotypes, the Fc region contains two identical protein fragments derived from the second (CH2) and third (CH3) constant domains of the antibody's two heavy chains, while the IgM and IgE Fc regions contain three heavy chain constant domains (CH domains 2-4) in each polypeptide chain. For IgG, the Fc region includes immunoglobulin domains CH2 and CH3, as well as the hinge between the CH1 and CH2 domains. Although the definition of the boundaries of the Fc region of an immunoglobulin heavy chain, as defined herein, may vary, the human IgG heavy chain Fc region is defined as extending from amino acid residues D221 for IgG1, V222 for IgG2, L221 for IgG3, and P224 for IgG4 to the carboxy-terminus of the heavy chain, this numbering is according to the EU index in Kabat. The CH2 domain of the human IgG Fc region extends from amino acid 237 to amino acid 340, and the CH3 domain is located C-terminal to the CH2 domain of the Fc region, i.e., the CH3 domain extends from amino acid 341 to amino acid 447 or 446 (if the C-terminal lysine residue is absent) or 445 (if the C-terminal glycine and lysine residues are absent) of IgG. As used herein, an Fc region may be a native sequence Fc, including any allotypic variants, or a variant Fc (e.g., a non-native Fc).

[0144] A "native sequence Fc region" or "native sequence Fc" comprises an amino acid sequence identical to the amino acid sequence of an Fc region found in nature. Native sequence human Fc regions include native sequence human IgG1 Fc regions, native sequence human IgG2 Fc regions, native sequence human IgG3 Fc regions, and native sequence human IgG4 Fc regions, as well as naturally occurring variants thereof. Native sequence Fc includes the various allotypes of Fc (see, e.g., Jefferis et al. (2009) mAbs 1:1).

[0145] The term "epitope" or "antigenic determinant," as defined, for example, by the particular method used to identify it, refers to a site on an antigen (e.g., truncated CDCP1) to which an immunoglobulin or antibody specifically binds. Epitopes can be formed both from contiguous amino acids (commonly linear epitopes) or noncontiguous amino acids juxtaposed by tertiary folding of a protein (commonly conformational epitopes). Epitopes formed from contiguous amino acids are usually, but not necessarily, retained upon exposure to denaturing solvents, whereas epitopes formed from tertiary folding are usually lost upon treatment with denaturing solvents. An epitope usually includes at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 amino acids in a unique spatial conformation. Methods for determining the epitope bound by a given antibody (i.e., epitope mapping) are well known in the art, and include, for example, immunoblotting and immunoprecipitation assays, in which overlapping or consecutive peptides (e.g., derived from truncated CDCP1) are tested for reactivity with a given antibody (e.g., anti-truncated CDCP1 antibody).Methods for determining the spatial conformation of epitopes include techniques in the art and those described herein, such as X-ray crystallography, X-ray cocrystallography, antigen mutation analysis, two-dimensional nuclear magnetic resonance, and HDX-MS (see, for example, Epitope Mapping Protocols in Methods in Molecular Biology, Vol. 66, GE Morris, Ed. (1996)).

[0146] The term "epitope mapping" refers to the process of identifying the molecular determinants of antibody-antigen recognition.

[0147] With respect to two or more antibodies, the term "binding to the same epitope" means that the antibodies bind to the same segment of amino acid residues, as determined by a given method. Techniques for determining whether the antibodies described herein bind to the "same epitope on truncated CDCP1" include epitope mapping methods such as X-ray analysis of crystals of antigen:antibody complexes, which provide atomic resolution of the epitope, and hydrogen / deuterium exchange mass spectrometry (HDX-MS). Other methods monitor the binding of antibodies to antigen fragments or to mutated variations of the antigen, where loss of binding due to modification of amino acid residues within the antigen sequence is often considered an indication of epitope content. Furthermore, computational combinatorial methods for epitope mapping may also be used. These methods rely on the ability of the antibody of interest to affinity isolate specific short peptides from combinatorial phage display peptide libraries. Antibodies with identical VH and VL or identical CDR1, 2, and 3 sequences are predicted to bind to the same epitope.

[0148] An antibody that "competes with another antibody for binding to a target" refers to an antibody that inhibits (partially or completely) the binding of the other antibody to the target. Whether two antibodies compete with each other for binding to a target, i.e., whether and to what extent one antibody inhibits the binding of the other antibody to the target, can be determined using known competition experiments, such as BIACORE® surface plasmon resonance (SPR) analysis. In some embodiments, an antibody competes with or inhibits the binding of another antibody to the target by at least 50%, 60%, 70%, 80%, 90%, or 100%. The level of inhibition or competition can vary depending on which antibody is the "blocking antibody" (i.e., the cold antibody that is first incubated with the target). Competitive assays can be performed, for example, as described in Ed Harlow and David Lane, Cold Spring Harb Protoc; 2006; doi:10.1101 / pdb.prot4277 or in Chapter 11 of "Using Antibodies" by Ed Harlow and David Lane, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA 1999. Two antibodies "cross-compete" if they block each other by at least 50% in both directions, regardless of whether one antibody or the other antibody contacts the antigen first in the competition experiment.

[0149] Competitive binding assays to determine whether two antibodies compete or cross-compete for binding include, for example, competition for binding to cells expressing truncated CDCP1 (e.g., human or mouse truncated CDCP1) by flow cytometry, such as that described in the Examples. Other methods include SPR (e.g., BIACORE®), solid-phase direct or indirect radioimmunoassay (RIA), solid-phase direct or indirect enzyme immunoassay (EIA), sandwich competition assay (see Stahli et al., Methods in Enzymology 9:242 (1983)); solid-phase direct biotin-avidin EIA (see Kirkland et al., J. Immunol. 137:3614 (1986)); solid-phase direct labeling assay, solid-phase direct labeling sandwich assay (see Harlow and Lane, Antibodies: A Laboratory Manual, Cold Spring Harbor Press (1988)); solid-phase direct labeling RIA using 1-125 label (see Morel et al., Mol. Immunol. 25(1):7 (1988)); solid-phase direct biotin-avidin EIA (see Cheung et al., Virology 176:546 (1986)); (1990)); and direct labeling RIA (Moldenhauer et al., Scand. J. Immunol. 32:77 (1990)).

[0150] As used herein, the terms "specific binding," "selective binding," "selectively binds," and "specifically binds" refer to antibody binding to an epitope on a predetermined antigen. Typically, an antibody (i) binds to an epitope of approximately 10 s, as determined, for example, by surface plasmon resonance (SPR) technology in a BIACORE® 2000 using a predetermined antigen, e.g., recombinant human truncated CDCP1, as the analyte and an antibody as the ligand, or by Scatchard analysis of antibody binding to antigen-positive cells. -7 Less than M, e.g., approximately 10 -8 M, 10 -9 M or 10-10 Equilibrium dissociation constants (K D ) and (ii) binds to a predetermined antigen with an affinity that is at least two-fold greater than its affinity for binding to a nonspecific antigen other than the predetermined antigen or a closely related antigen (e.g., BSA, casein). Thus, an antibody that "specifically binds to human truncated CDCP1" has an affinity of at least 10 -7 M or less, e.g., about 10 -8 Under M, 10 -9 Less than M or 10 -10 Less than M or even lower K D The term "antibody that cross-reacts with cynomolgus monkey truncated CDCP1" refers to an antibody that binds to cell-bound human truncated CDCP1. -7 M or less, e.g., about 10 -8 Under M, 10 -9 Less than M or 10 -10 Less than M or even lower K D refers to an antibody that binds to truncated cynomolgus monkey CDCP1 at a specific binding site. In some embodiments, such antibodies that do not cross-react with truncated CDCP1 from non-human species exhibit essentially undetectable binding to these proteins in standard binding assays.

[0151] As used herein, the term "k assoc " or "k a " refers to the association rate of a particular antibody-antigen interaction, whereas the term "k dis " or "k d " refers to the dissociation rate of a particular antibody-antigen interaction. D " is used herein to refer to the dissociation constant, which is k a k for d The proportion of (i.e., k d / k a ) and expressed as molar concentration (M). D The K value can be determined using methods well established in the art. DAvailable methods for determining β include surface plasmon resonance, the BIACORE® system, or flow cytometry and Scatchard analysis.

[0152] As used herein, the term "high affinity" with respect to an IgG antibody means that the antibody has a high affinity for the target antigen. -8 M or less, 10 -9 M or less or 10 -10 K below M D However, "high affinity" binding can vary for other antibody isotypes. For example, "high affinity" binding for an IgM isotype refers to an antibody having a binding affinity of 10 -10 M or less or 10 -8 K below M D It refers to having.

[0153] The term "EC" in reference to in vitro or in vivo assays using antibodies or antigen-binding fragments thereof 50 " refers to the concentration of an antibody or antigen-binding fragment thereof that induces 50% of the maximal response, i.e., a response that is halfway between the maximal response and the baseline.

[0154] The term "naturally occurring" as applied to an object herein refers to the fact that the object can be found in nature. For example, naturally occurring polypeptide or polynucleotide sequences exist in organisms (including viruses) that can be isolated from sources in nature and have not been intentionally modified by humans in a laboratory.

[0155] A "polypeptide" refers to a chain comprising at least two consecutively linked amino acid residues, with no upper limit to the length of the chain. One or more amino acid residues in a protein may contain modifications, such as, but not limited to, glycosylation, phosphorylation, or disulfide bond formation. A "protein" may include one or more polypeptides.

[0156] The term "nucleic acid molecule" as used herein includes DNA molecules and RNA molecules. A nucleic acid molecule may be single-stranded or double-stranded, and may be cDNA.

[0157] A "conservative amino acid substitution" refers to the replacement of an amino acid residue with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine, tryptophan), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine), β-branched side chains (e.g., threonine, valine, isoleucine), and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). In some embodiments, a predicted non-essential amino acid residue in an anti-human or mouse truncated CDCP1 antibody is replaced with another amino acid residue from the same side chain family. Methods for identifying conservative nucleotide and amino acid substitutions that do not eliminate antigen binding are well known in the art (see, e.g., Brummel et al., Biochem. 32:1180-1187 (1993); Kobayashi et al. Protein Eng. 12(10):879-884 (1999); and Burks et al. Proc. Natl. Acad. Sci. USA 94:412-417 (1997)).

[0158] With respect to nucleic acids, the term "substantial homology" indicates that two nucleic acids or their designated sequences, when optimally aligned and compared, are identical, with appropriate nucleotide insertions or deletions, in at least about 80%, at least about 90%-95%, or at least about 98%-99.5% of the nucleotides. Alternatively, substantial homology exists when the segments will hybridize under selective hybridization conditions, to the complement of the strand.

[0159] With respect to polypeptides, the term "substantial homology" indicates that two polypeptides or their designated sequences, when optimally aligned and compared, are identical, with appropriate amino acid insertions or deletions, in at least about 80%, at least about 90%-95%, or at least about 98%-99.5% of the amino acids.

[0160] The percent identity between two sequences is a function of the number of identical positions shared by the sequences (i.e., % homology = number of identical positions / total number of positions x 100), and takes into account the number of gaps and the length of each gap that need to be introduced for optimal alignment of the two sequences. The comparison of sequences and determination of percent identity between two sequences can be accomplished using a mathematical algorithm, as described in the non-limiting examples below.

[0161] The percent identity between two nucleotide sequences can be determined using the GAP program in the GCG software package (available at worldwideweb.gcg.com) using a NWSgapdna.CMP matrix and gap weights of 40, 50, 60, 70, or 80 and length weights of 1, 2, 3, 4, 5, or 6. The percent identity between two nucleotide or amino acid sequences can also be determined using the algorithm of E. Meyers and W. Miller (CABIOS, 4:11-17 (1989)) as incorporated into the ALIGN program (version 2.0), using a PAM120 weight residue table, a gap length penalty of 12, and a gap penalty of 4. Furthermore, percent identity between two amino acid sequences can be determined using the Needleman and Wunsch (J. Mol. Biol. (48):444-453 (1970)) algorithm incorporated into the GAP program in the GCG software package (available at http: / / www.gcg.com), using either a Blossum 62 matrix or a PAM250 matrix and a gap weight of 16, 14, 12, 10, 8, 6, or 4 and a length weight of 1, 2, 3, 4, 5, or 6.

[0162] The nucleic acid and protein sequences described herein can further be used as "query sequences" to perform searches against public databases, for example, to identify related sequences. Such searches can be performed using the NBLAST and XBLAST programs (version 2.0) of Altschul, et al. (1990) J. Mol. Biol. 215:403-10. To obtain nucleotide sequences homologous to the nucleic acid molecules described herein, BLAST nucleotide searches can be performed using the NBLAST program, score = 100, word length = 12. To obtain amino acid sequences homologous to the protein molecules described herein, BLAST protein searches can be performed using the XBLAST program, score = 50, word length = 3. To obtain gapped alignments for comparison purposes, gapped BLAST can be used, as described in Altschul et al., (1997) Nucleic Acids Res. 25(17):3389-3402. When utilizing BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., XBLAST and NBLAST) can be used. See worlddeweb.ncbi.nlm.nih.gov.

[0163] Nucleic acids may be present in whole cells, in a cell lysate, or in a partially purified or substantially pure form. A nucleic acid is "isolated" or "substantially purified" when it has been purified from other cellular components or other contaminants, such as other cellular nucleic acids (e.g., other parts of chromosomes) or proteins, by standard techniques, including alkaline / SDS treatment, CsCl banding, column chromatography, agarose gel electrophoresis, and others known in the art. See F. Ausubel, et al., ed., Current Protocols in Molecular Biology, Greene Publishing and Wiley Interscience, New York (1987).

[0164] Nucleic acids, e.g., cDNAs, may be mutated according to standard techniques for providing gene sequences. For coding sequences, these mutations may affect the desired amino acid sequence. In particular, DNA sequences that are substantially homologous to or derived from natural V, D, J, constant, switch, and other such sequences described herein are contemplated (where "derived" indicates that the sequence is identical to or modified from another sequence).

[0165] As used herein, the term "vector" refers to a nucleic acid molecule capable of transporting another nucleic acid to which it is linked. One type of vector is a "plasmid," which refers to a circular double-stranded DNA loop into which additional DNA segments can be ligated. Another type of vector is a viral vector; additional DNA segments can be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) can be integrated into the genome of a host cell upon introduction into the host cell, thereby replicating along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operably linked. Such vectors are referred to herein as "recombinant expression vectors" (or simply "expression vectors"). In general, expression vectors useful in recombinant DNA techniques are often in the form of plasmids. Because the plasmid is the most commonly used form of vector, "plasmid" and "vector" can be used interchangeably herein. However, other forms of expression vectors, such as viral vectors (eg, replication defective retroviruses, adenoviruses and adeno-associated viruses), which serve equivalent functions are also included.

[0166] The term "recombinant host cell" (or simply "host cell"), as used herein, refers to a cell that contains a nucleic acid that does not naturally occur in the cell, and may be a cell into which a recombinant expression vector has been introduced. It should be understood that such terms refer not only to the particular subject cell, but also to the progeny of such a cell. Because certain modifications may occur in later generations, either due to mutation or environmental influences, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term "host cell" as used herein.

[0167] "Immune response," as understood in the art, generally refers to a biological response in a vertebrate to foreign substances or abnormal, e.g., cancerous, cells, which protects the organism from these substances and the diseases they cause. Immune responses are mediated by the action of one or more cells of the immune system (e.g., T lymphocytes, B lymphocytes, natural killer (NK) cells, macrophages, eosinophils, mast cells, dendritic cells, or neutrophils) and soluble macromolecules (including antibodies, cytokines, and complement) produced by any of these cells or the liver, resulting in the selective targeting, binding, damage, destruction, and / or elimination from the vertebrate body of invading pathogens, pathogen-infected cells or tissues, cancerous or other abnormal cells, or, in the case of autoimmunity or pathological inflammation, normal human cells or tissues. Immune responses include, for example, the activation or inhibition of T cells, e.g., effector T cells, Th cells, CD4+ cells, CD8+ T cells, or Treg cells, or the activation or inhibition of any other cells of the immune system, e.g., NK cells.

[0168] An "immunomodulator" or "immunoregulator" refers to a substance that may be involved in regulating, controlling, or modifying the immune response, e.g., a substance that targets components of a signal transduction pathway. "Modulation," "control," or "modulation" of an immune response refers to any change in cells of the immune system or in the activity of such cells (e.g., effector T cells, such as Th1 cells). Such modulation includes stimulation or suppression of the immune system and may be manifested by an increase or decrease in the numbers of various cell types, an increase or decrease in the activity of these cells, or any other change that may occur within the immune system. Both inhibitory and stimulatory immunomodulators have been identified, some of which may have enhanced function in the tumor microenvironment. In some embodiments, an immunomodulator targets a molecule on the surface of T cells. An "immunomodulatory target" or "immunoregulatory target" is a molecule, e.g., a cell surface molecule, that is targeted for binding by a substance, agent, moiety, compound, or molecule, and whose activity is altered by the binding of the substance, agent, moiety, compound, or molecule. Immunomodulatory targets include, for example, cell surface receptors ("immunomodulatory receptors") and receptor ligands ("immunomodulatory ligands").

[0169] "Immunotherapy" refers to the treatment of a subject suffering from or at risk of developing or suffering from a recurrence of a disease by methods involving inducing, enhancing, suppressing or otherwise modifying the immune system or immune response.

[0170] "Immunostimulating therapy" or "immunostimulatory therapy" refers to a therapy that results in an increase (induction or enhancement) of the immune response in a subject, for example, to treat cancer.

[0171] "Enhancing an endogenous immune response" means increasing the efficacy or potency of an existing immune response in a subject. This increased efficacy and potency can be achieved, for example, by overcoming mechanisms that suppress the endogenous host immune response or by stimulating mechanisms that enhance the endogenous host immune response.

[0172] "Effector T" ("T eff ") cells are T cells (e.g., CD4 T cells) with cytolytic activity that secrete cytokines and activate and induce other immune cells. + and CD8 + The term "cleaved CDCP1" refers to T cells, as well as T helper (Th) cells, e.g., Th1 cells, but does not include regulatory T cells (Treg cells). Certain anti-cleaved CDCP1 antibodies, or antigen-binding fragments thereof, described herein inhibit T eff Cells, e.g., CD4 + and CD8 + T eff cells, as well as Th1 cells.

[0173] The increased ability to stimulate an immune response or the immune system may be due to increased agonistic activity of T cell costimulatory receptors and / or increased antagonistic activity of inhibitory receptors. The increased ability to stimulate an immune response or the immune system may be due to increased activity of EC in assays that measure immune responses, such as assays that measure changes in cytokine or chemokine release, cytolytic activity (determined directly on target cells or indirectly via detection of CD107a or granzymes), and proliferation. 50 Or may be reflected by a doubling of the maximal activity level. The ability to stimulate an immune response or activity of the immune system may be enhanced by at least 10%, 30%, 50%, 75%, 2-fold, 3-fold, 5-fold or more.

[0174] As used herein, the term "linked" refers to the association of two or more molecules. The linkage can be covalent or non-covalent. The linkage can also be genetic (i.e., recombinantly fused). Such linkage can be achieved using a variety of art-recognized techniques, such as chemical conjugation and recombinant protein production.

[0175] As used herein, "administering" refers to the physical introduction of a composition containing a therapeutic agent into a subject using any of a variety of methods and delivery systems known to those skilled in the art. Alternative routes of administration for the anti-cleaved CDCP1 antibodies (e.g., anti-human cleaved CDCP1) described herein include intravenous, intraperitoneal, intramuscular, subcutaneous, spinal, or other parenteral routes of administration, for example, by injection or infusion. As used herein, the phrase "parenteral administration" refers to modes of administration other than enteral and topical administration, usually by injection, and includes, but is not limited to, intravenous, intraperitoneal, intramuscular, intraarterial, intrathecal, intralymphatic, intralesional, intraarticular, intraorbital, intracardiac, intradermal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal, epidural, and intrasternal injection and infusion, as well as in vivo electroporation. Alternatively, the antibodies described herein can be administered by a non-parenteral route, such as a topical, epithelial, or mucosal route of administration, e.g., intranasally, orally, vaginally, rectally, sublingually, or topically. The administration can be performed, for example, once, multiple times, and / or over one or more extended periods of time.

[0176] As used herein, the term "T cell-mediated response" refers to a response mediated by effector T cells (e.g., CD8 + cells) and helper T cells (e.g., CD4 + "T-cell" refers to responses mediated by T cells, including T cells. T cell-mediated responses include, for example, T cell cytotoxicity and proliferation.

[0177] As used herein, the term "cytotoxic T lymphocyte (CTL) response" refers to an immune response induced by cytotoxic T cells. A CTL response is a response induced by CD8 +It is primarily mediated by T cells.

[0178] As used herein, the phrase "inhibiting tumor growth" includes any measurable decrease in tumor growth, e.g., at least about 10%, e.g., at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 99%, or 100% inhibition of tumor growth. In some embodiments, tumor growth inhibition is measured as tumor growth inhibition percent (TGI%). TGI% is calculated according to the formula: [1-(T t / T0) / (C t / C0))] / [(C t -C0) / C t ]*100[Formula 1](In the formula, T t = individual tumor size of treated animals at time "t", TO = individual tumor size of treated animals at the first measurement, C t The TGI can be determined by calculating the TGI at time "t" calculated from all treated animals according to the following formula: TGI = median tumor size of control animals at time "t", C0 = median tumor size of control animals at the first measurement.

[0179] As used herein, "cancer" refers to a broad group of diseases characterized by the uncontrolled growth of abnormal cells in the body. Uncontrolled cell division can lead to the formation of malignant tumors or cells that can invade adjacent tissues and metastasize to distant parts of the body via the lymphatic system or bloodstream.

[0180] The terms "treat," "treating," and "treatment," as used herein, refer to any type of intervention or process performed on a subject or the administration of an active agent to a subject, with the goal of reversing, alleviating, ameliorating, inhibiting, or slowing or preventing the progression, occurrence, severity, or recurrence of symptoms, complications, conditions, or biochemical manifestations associated with a disease, or enhancing overall survival. Treatment may be of subjects with a disease or subjects without a disease (e.g., for prophylaxis).

[0181] The term "effective dose" or "effective dosage" is defined as an amount sufficient to achieve or at least partially achieve a desired effect. A "therapeutically effective amount" or "therapeutically effective dosage" of a drug or therapeutic agent is any amount of drug that, when used alone or in combination with another therapeutic agent, promotes disease regression as evidenced by a decrease in the severity of disease symptoms, an increase in the frequency and duration of disease symptom-free periods, an increase in overall survival (the length of time that a patient diagnosed with the disease remains alive from the date of diagnosis or treatment initiation of the disease, e.g., cancer), or prevention of functional impairment or disability due to disease affliction. A therapeutically effective amount or dosage of a drug includes a "prophylactically effective amount" or "prophylactically effective dosage," which is the amount of drug that, when administered alone or in combination with another therapeutic agent to a subject at risk of developing a disease or suffering from a recurrence of a disease, inhibits the development or recurrence of the disease. The ability of a therapeutic agent to promote disease regression or inhibit the occurrence or recurrence of disease can be evaluated using a variety of methods known to those of skill in the art, for example, by assaying the activity of the agent in human subjects during clinical trials, in animal model systems predictive of efficacy in humans, or in in vitro assays.

[0182] For example, an anti-cancer drug is a drug that promotes cancer regression in a subject. In some embodiments, a therapeutically effective amount of a drug promotes cancer regression to the point of eliminating the cancer. "Promoting cancer regression" means that administering an effective amount of a drug, alone or in combination with an anti-neoplastic agent, results in a reduction in tumor growth or size, tumor necrosis, a decrease in the severity of at least one disease symptom, an increase in the frequency and duration of disease symptom-free periods, an increase in overall survival, prevention of functional impairment or disability due to disease affliction, or otherwise amelioration of disease symptoms in a patient. Furthermore, the terms "effective" and "efficacy" in relation to treatment include both pharmacological effectiveness and physiological safety. Pharmacological effectiveness refers to the ability of a drug to promote cancer regression in a patient. Physiological safety refers to the level of toxicity or other adverse physiological effects (adverse effects) at the cellular, organ, and / or organismal levels resulting from the administration of a drug.

[0183] For example, in the treatment of tumors, a therapeutically effective amount or dosage of a drug inhibits cell or tumor growth by at least about 20%, at least about 40%, at least about 60%, or at least about 80% compared to untreated subjects. In some embodiments, a therapeutically effective amount or dosage of a drug completely inhibits cell or tumor growth, i.e., inhibits cell or tumor growth by 100%. The ability of a compound to inhibit tumor growth can be evaluated using the assays described below. Alternatively, the properties of the composition can be evaluated by examining the ability of the compound to inhibit cell growth, and such inhibition can be measured in vitro by assays known to those skilled in the art. In some embodiments described herein, tumor regression can be observed and can last for a period of at least about 20 days, at least about 40 days, or at least about 60 days.

[0184] The term "patient" includes human and other mammalian subjects receiving either prophylactic or therapeutic treatment.

[0185] As used herein, the term "subject" includes any human or non-human animal. For example, the methods and compositions described herein can be used to treat subjects with cancer. The term "non-human animal" includes all vertebrates, such as mammals and non-mammals, including non-human primates, sheep, dogs, cows, chickens, amphibians, reptiles, etc.

[0186] As used herein, the terms "ug" and "uM" are used synonymously with "μg" and "μM", respectively.

[0187] The various aspects described herein are described in further detail in the following subsections.

[0188] II. Anti-human and mouse cleaved CDCP1 antibodies Described herein are antibodies, e.g., fully human antibodies, that can specifically bind to truncated CDCP1, specifically bind to the same truncated CDCP1 epitope as a reference antibody, and / or cross-compete with the reference antibody for binding to the truncated CDCP1 epitope. In some embodiments, an anti-CDCP1 antibody or antigen-binding fragment thereof that specifically binds to truncated CDCP1 preferentially binds to truncated CDCP1 and is characterized by specific functional features or properties. For example, the antibody specifically binds to mammalian (e.g., human and mouse) truncated CDCP1 and exhibits the following functional properties: (a) inhibiting tumor growth and / or metastasis; (b) reducing tumor volume; (c) increasing progression-free survival; (d) increasing overall survival; (e) promoting CDCP1 internalization and / or degradation; and (f) any combination of these indicates one or more of:

[0189] In some embodiments, the anti-CDCP1 antibodies or antigen-binding fragments thereof described herein do not bind to full-length human CDCP1 at detectable levels.

[0190] In some embodiments, the anti-human truncated CDCP1 antibodies or antigen-binding fragments thereof described herein bind with high affinity, e.g., at least 10 -6 M or less, 10 -7 M or less, 10 -8 M or less, 10 -9 M or less, 10 -10 M or less, 10 -11 M or less, 10 -12 M or less, 10 -12 M~10 -7 M, 10 -11 M~10 -7 M, 10 -10 M~10 -7 M, or 10 -9 M~10 -7 K of M D In some embodiments, the anti-CDCP1 antibody binds to human truncated CDCP1 at 10, as determined by biolayer interferometry analysis using, for example, an Octet instrument (ForteBio). -6 M or less, 10 -7 M or less, 10 -8 M or less, 10 -9 M (1nM) or less, 10 -10 M or less, 10 -12 M~10 -7 M, 10 -11 M~10 -7 M, 10 -10 M~10 -7 M, 10 -9 M~10 -7 M, or 10 -8 M~10 -7 K of M DIn some embodiments, the anti-human cleaved CDCP1 antibody has an EC50 of 100 nM or less, 10 nM or less, 1 nM or less, 100 nM to 0.01 nM, 100 nM to 0.1 nM, 100 nM to 1 nM, or 10 nM to 1 nM, or 10 ug / mL or less, 5 ug / mL or less, 1 ug / mL or less, 0.9 ug / mL or less, 0.8 ug / mL or less, 0.7 ug / mL or less, 0.6 ug / mL or less, 0.5 ug / mL or less, 0.4 ug / mL or less, 0.3 ug / mL or less, 0.2 ug / mL or less, 0.1 ug / mL or less, 0.05 ug / mL or less, or 0.01 ug / mL or less, as determined by, for example, ELISA. 50 EC 50 In some embodiments, the anti-cleaved CDCP1 antibodies described herein bind to human truncated CDCP1 at, for example, 10 -6 M or less, 10 -7 M or less, 10 -8 M or less, 10 -9 M or less, 10 -10 M or less, 10 -11 M or less, 10 -12 M or less, 10 -12 M~10 -7 M, 10 -11 M~10 -7 M, 10 -10 M~10 -7 M, or 10 -9 M~10 -7 K of M D In some embodiments, the anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof described herein bind to murine truncated CDCP1 at, for example, 10 -6 M or less, 10 -7 M or less, 10 -8 M or less, 10 -9 M or less, 10 -10 M or less, 10 -11 M or less, 10 -12 M or less, 10 -12 M~10 -7 M, 10 -11 M~10 -7 M, 10 -10 M~10 -7 M, or 10 -9 M~10 -7 K of MD and binds to truncated cynomolgus monkey CDCP1.

[0191] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof is about 5×10 -4 M or less, approximately 1×10 -4 M or less, 5×10 -5 M or less, approximately 1×10 -5 M or less, approximately 1×10 -6 M or less, approximately 1×10 -7 M or less, or approximately 1 x 10 -8 K below M D It specifically binds to human truncated CDCP1 and D is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

[0192] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof is at least about 1 x 10 3 ms -1 , at least about 5 × 10 3 ms -1 , at least about 1 x 10 4 ms -1 , at least about 5 × 10 4 ms -1 , at least about 1 x 10 5 ms -1 , at least about 5 × 10 5 ms -1 , or at least about 1 × 10 6 ms -1 On-rate (k on ) specifically binds to human truncated CDCP1 and k on is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

[0193] In some embodiments, the anti-cleaved CDCP1 antibody or antigen-binding fragment thereof is at least about 1 x 10 3 ms -1 , at least about 5 × 10 3 ms -1 , at least about 1 x 104 ms -1 , at least about 5 × 10 4 ms -1 , at least about 1 x 10 5 ms -1 , at least about 5 × 10 5 ms -1 , or at least about 1 × 10 6 ms -1 Off-rate (k off ) specifically binds to human CDCP1 and k off is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

[0194] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises VL complementarity-determining region (CDR) 1, VL-CDR2, and VL-CDR3, and the VH comprises SEQ ID NOs: 1 (SVSSAVA), 2 (SASSLY), 268 (SX1X2X3X4X5), 269 (X6FSSX7SI), 270 (SIYPYSGSTX8), and 271 (X9X 10 X 12 SX 12 YSHTWWVSYGX 13 ) or 272(X 14 YWVX 15 FWYGHFSYYRPAL), X1 = glycine (G), serine (S), methionine (M), leucine (L), valine (V), or arginine (R); X2 = glutamine (Q), serine (S), glutamic acid (E), asparagine (N), lysine (K), proline (P), arginine (R), leucine (L), or histidine (H); X3 = arginine (R), serine (S), valine (V), tryptophan (W), leucine (L), lysine (K), methionine (M), glutamine (Q), or proline (P); X4 = proline (P), leucine (L), threonine (T), or serine (S); X5 = isoleucine (I), alanine (A), methionine (M), lysine (K), valine (V), leucine (L), phenylalanine (F); X6 = no amino acid, aspartic acid (D), or asparagine (N); X7 = serine (S) or tyrosine (Y); X8 = serine (S) or tyrosine (Y); X9 = glutamine (Q), arginine (R), or lysine (K); X 10 = serine (S), asparagine (N), threonine (T), glycine (G), alanine (A), or aspartic acid (D); X 11 = glutamine (Q) or histidine (H), X 12 = tyrosine (Y) or phenylalanine (F), X 13 = methionine (M), alanine (A), isoleucine (I), leucine (L), or valine (V); X 14 = threonine (T) or isoleucine (I), X 15 = glutamine (Q) or aspartic acid (D).

[0195] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises a VL complementarity-determining region (CDR) 1 sequence of SEQ ID NO: 1 (SVSSAVA), a VL-CDR2 sequence of SEQ ID NO: 2 (SASSLY), and a VL-CDR3 sequence of SEQ ID NO: 8 (TGQRPM), 23 (FMRPAF), 16 (TAQSPL), 11 (VELVPM), 12 (AGKRPL), or 14 (LGVRAA); and the VH comprises a VH-CDR1 sequence of SEQ ID NO: 269 (X1FSSX2SI), a VH-CDR2 sequence of SEQ ID NO: 270 (SIYPYSGSTX3), and a VH-CDR3 sequence of SEQ ID NO: 271 (X4X5X6SX7YSHTWWVSYGX8) or SEQ ID NO: 272 (X9YWVX 10 FWYGHFSYYRPAL), X1 = no amino acid, aspartic acid (D), or asparagine (N); X2 = serine (S) or tyrosine (Y); X3 = serine (S) or tyrosine (Y); X4 = glutamine (Q), arginine (R), or lysine (K); X5 = serine (S), asparagine (N), threonine (T), glycine (G), alanine (A), or aspartic acid (D); X6 = glutamine (Q) or histidine (H); X7 = tyrosine (Y) or phenylalanine (F); X8 = methionine (M), alanine (A), isoleucine (I), leucine (L), or valine (V); X9 = threonine (T) or isoleucine (I); X 10 = glutamine (Q) or aspartic acid (D).

[0196] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises VL complementarity-determining region (CDR) 1 (VL-CDR1), VL-CDR2, and VL-CDR3, and the VH comprises VH-CDR1, VH-CDR2, and VH-CDR3, wherein the VL-CDR3 comprises an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 3 to 25. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 3 to 25, as disclosed in Table 1 below. In some embodiments, the anti-CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO:3.

[0197] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR2 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence of SEQ ID NO: 30 or 31. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VH-CDR2 comprising the amino acid sequence of SEQ ID NO: 30 or 31, as disclosed in Table 1 below. In one embodiment, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 30.

[0198] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR1 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 26-29, 109, and 111. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 26-29, 109, and 111, as disclosed in Table 1 below. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 26.

[0199] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR1 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence of SEQ ID NO: 1. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, as disclosed in Table 1 below.

[0200] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR2 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence of SEQ ID NO: 2. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, as disclosed in Table 1 below.

[0201] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 20, 32-47, and 105. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 20, 32-47, and 105, as disclosed in Table 1 below. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 32. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 33. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 34. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 35. In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 36.

[0202] In certain embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises: (a) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 32; (b) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 33; (c) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 34; (d) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 35, or (e) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO: 26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO: 30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO: 36.

[0203] Table 1. Amino acid sequences of the variable light and heavy chain CDRs of anti-human truncated CDCP1 antibodies [Table 1] [Table 2] [Table 3] [Table 4]

[0204] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises VL complementarity-determining region (CDR) 1 (VL-CDR1), VL-CDR2, and VL-CDR3, and the VH comprises VH-CDR1, VH-CDR2, and VH-CDR3, wherein VL-CDR3 comprises an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NO: 48 or 49. In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR3 comprising the amino acids of SEQ ID NO: 48 or 49, as disclosed in Table 2 below.

[0205] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR2 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 52 to 55. In some embodiments, the anti-mouse truncated CDCP1 antibody comprises a VH-CDR2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 52 to 55, as disclosed in Table 2 below.

[0206] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR1 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence of SEQ ID NO: 50 or 51. In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR1 comprising the amino acid sequence of SEQ ID NO: 50 or 51, as disclosed in Table 2 below.

[0207] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR1 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence of SEQ ID NO: 1. In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, as disclosed in Table 2 below.

[0208] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR2 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence of SEQ ID NO: 2. In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, as disclosed in Table 2 below.

[0209] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising an amino acid sequence having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 56 to 60. In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH-CDR3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 56 to 60, as disclosed in Table 2 below.

[0210] Table 2. Amino acid sequences of the variable light and heavy chain CDRs of anti-mouse truncated CDCP1 antibodies [Table 5] [Table 6]

[0211] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 61, 65, 67, 69, 71, 73, 75, 79, 80, 81, 82, 83, 84, 85, 86, 87, 89, 91, 99, 103, 107, 123, and 133. In certain embodiments, the VH comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 61, 65, 67, 69, 71, 73, 75, 79, 80, 81, 82, 83, 84, 85, 86, 87, 89, 91, 99, 103, 107, 123, and 133, as disclosed in Table 3 below.

[0212] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 62, 76, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, and 132. In certain embodiments, the VL comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 62, 76, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, and 132, as disclosed in Table 3 below.

[0213] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 61. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 61. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 61 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 61 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0214] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0215] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 67. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 67. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 67 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 67 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0216] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 69. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 69. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 69 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 69 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0217] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 71. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 71. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 71 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 71 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0218] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 73. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 73. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 74. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 73 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 73 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0219] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 75. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 75. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 76. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 76. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 75 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 76. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 75 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 76 for binding to human truncated CDCP1.

[0220] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 79. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 79. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 76. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 76. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 79 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 76. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 79 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 76 for binding to human truncated CDCP1.

[0221] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 76. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 76. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 76. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 76 for binding to human truncated CDCP1.

[0222] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 83. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 83. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 83, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 83 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0223] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 85. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 85. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 85, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 85 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0224] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 87. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 87. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 87 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 87 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0225] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 89. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 89. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 89 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 89 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0226] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 91. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 91. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 96. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 91 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 91 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0227] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 94. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 94. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 94. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 94 for binding to human truncated CDCP1.

[0228] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 96. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 96. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 96. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 96 for binding to human truncated CDCP1.

[0229] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 98. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 98. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 98. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 98 for binding to human truncated CDCP1.

[0230] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 99. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 100. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 100. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 100. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 99 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 100.

[0231] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 102. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 102. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 102. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 102.

[0232] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 103. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 103. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 104. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 104. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 103, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 104. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 103 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 104 for binding to human truncated CDCP1.

[0233] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 99. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 106. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 106. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 106. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 99 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 106 for binding to human truncated CDCP1.

[0234] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 107. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 107. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 108. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 108. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 108. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 107 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 108.

[0235] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 99. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 110. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 110. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 110. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 99 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 110.

[0236] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 99. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 112. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 112. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 112. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 99 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 112.

[0237] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 114. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 114. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 114. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 114.

[0238] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 99. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 116. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 116. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 116. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 99 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 116 for binding to human truncated CDCP1.

[0239] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 118. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 118. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 118. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 118.

[0240] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 120. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 120. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 120. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 120.

[0241] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 122. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 122. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 122. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 122.

[0242] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 123. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 123. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 124. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 124. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 123, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 124. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 123 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 124.

[0243] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 107. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 107. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 126. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 126. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 126. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 107 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 126 for binding to human truncated CDCP1.

[0244] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 99. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 128. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 128. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 128. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 99 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 128.

[0245] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 99. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 130. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 130. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 130. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 99 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 130.

[0246] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 65. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 132. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 132. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 132. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 65 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 132.

[0247] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 133. In particular embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 133. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 76. In certain aspects, the VL comprises the amino acid sequence set forth in SEQ ID NO: 76. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 133, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 76. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 133 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 76.

[0248] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 80. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 80. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 80, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 80 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0249] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 81. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 81. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 81 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 81 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0250] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 82. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 82. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 82 and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes for binding to human truncated CDCP1 with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 82 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62.

[0251] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 84. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 84. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 84, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 84 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0252] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 86. In certain embodiments, the VH comprises the amino acid sequence set forth in SEQ ID NO: 86. In some embodiments, the anti-human truncated CDCP1 antibody comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to SEQ ID NO: 62. In certain embodiments, the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In some aspects, the VH comprises the amino acid sequence set forth in SEQ ID NO: 86, and the VL comprises the amino acid sequence set forth in SEQ ID NO: 62. In another embodiment, the anti-CDCP1 antibody or antigen-binding fragment thereof cross-competes with an antibody or antigen-binding fragment thereof comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 86 and a VL comprising the amino acid sequence set forth in SEQ ID NO: 62 for binding to human truncated CDCP1.

[0253] Table 3: Variable heavy (VH) and variable light (VL) chain amino acid sequences of anti-human truncated CDCP1 antibodies [Table 7] [Table 8] [Table 9] [Table 10] [Table 11]

[0254] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VH comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 135, 139, 143, 145, 147, 149, 151, 153, 155, 157, 159, and 161. In certain embodiments, the VH comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 135, 139, 143, 145, 147, 149, 151, 153, 155, 157, 159, and 161, as disclosed in Table 4 below.

[0255] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a VL comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 136 and 140. In particular embodiments, the VL comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 136 and 140, as disclosed in Table 4 below.

[0256] Table 4: Variable heavy (VH) and variable light (VL) chain amino acid sequences of anti-mouse truncated CDCP1 antibodies [Table 12] [Table 13]

[0257] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a heavy chain (HC) comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 290, 291, 292, 293, 294, 298, 300, 302, 310, and 315. In certain embodiments, the HC comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 290, 291, 292, 293, 294, 298, 300, 302, 310, and 315, as disclosed in Table 5 below. In certain embodiments, the heavy chain amino acid sequence comprises one or more deletions, substitutions, or mutations within the immunoglobulin constant region, e.g., within the CH1 domain, CH2 domain, CH3 domain, or hinge region.

[0258] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a light chain (LC) comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 316, 317, 323, 324, 326, 327, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, and 352. In certain embodiments, the LC comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 316, 317, 323, 324, 326, 327, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, and 352, as disclosed in Table 5 below.

[0259] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a heavy chain (HC) and a light chain (LC), wherein the HC of the antibody or antigen-binding fragment thereof is at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 290, 291, 292, 293, 294, 298, 300, 302, 310, and 315. % sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 316, 317, 323, 324, 326, 327, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, and 352, wherein the LC comprises an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 316, 317, 323, 324, 326, 327, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, and 352.

[0260] In some embodiments, the anti-human truncated CDCP1 antibody or antigen-binding fragment thereof comprises a heavy chain (HC) and a light chain (LC), wherein the HC of the antibody or antigen-binding fragment thereof is selected from the group consisting of SEQ ID NOs: 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 290, 291, 292, 293, 294, 298, 300, 302, 310, and 315. and wherein the LC comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 316, 317, 323, 324, 326, 327, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, and 352.

[0261] Table 5. Heavy chain (HC) and light chain (LC) amino acid sequences of anti-human truncated CDCP1 antibodies [Table 14] [Table 15]

[0262] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a heavy chain (HC) comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 353-366. In certain embodiments, the HC comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 353-366, as disclosed in Table 6 below. In certain embodiments, the heavy chain amino acid sequence comprises one or more deletions, substitutions, or mutations within the immunoglobulin constant region, e.g., within the CH1 domain, CH2 domain, CH3 domain, or hinge region.

[0263] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a light chain (LC) comprising an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 367-372. In certain embodiments, the LC comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 367-372, as disclosed in Table 6 below.

[0264] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a heavy chain (HC) and a light chain (LC), wherein the HC of the antibody or antigen-binding fragment thereof comprises an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 353-366, and the LC comprises an amino acid sequence having at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 367-372.

[0265] In some embodiments, the anti-mouse truncated CDCP1 antibody or antigen-binding fragment thereof comprises a heavy chain (HC) and a light chain (LC), wherein the HC of the antibody or antigen-binding fragment thereof comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 353-366, and the LC comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 367-372.

[0266] Table 6. Heavy chain (HC) and light chain (LC) amino acid sequences of anti-mouse truncated CDCP1 antibodies [Table 16]

[0267] The VH domains described herein, or one or more CDRs thereof, can be linked to a constant domain to form a heavy chain, e.g., a full-length heavy chain. Similarly, the VL domains described herein, or one or more CDRs thereof, can be linked to a constant domain to form a light chain, e.g., a full-length light chain. A full-length heavy chain (excluding the C-terminal lysine (K) or C-terminal glycine and lysine (GK), as appropriate, which may be absent) and a full-length light chain can be combined to form a full-length antibody.

[0268] The VH domains described herein may be fused to the constant domain of a human IgG, e.g., IgG1, IgG2, IgG3, or IgG4, either naturally occurring or, for example, modified as further described herein. For example, the VH domain may be fused to a human IgG, e.g., IgG1, constant region, e.g., the amino acid sequence of the wild-type human IgG1 constant domain: ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 381) or the amino acid sequence of any VH domain described herein fused to that of an allotypic variant of SEQ ID NO: 381, having the following amino acid sequence: [ka] (SEQ ID NO: 382, ​​allotype-specific amino acid residues are shown in bold and underlined).

[0269] The VH domain of the anti-human truncated CDCP1 antibody may comprise an effector-less constant region, for example, the following effector-less human IgG1 constant domain amino acid sequence: [ka] (SEQ ID NO: 383, "IgG1.1f", containing the underlined substitutions L234A, L235E, G237A, A330S and P331S) or [ka] (SEQ ID NO: 384, "IgG1.3f", with the underlined substitutions L234A, L235E and G237A).

[0270] For example, an allotypic variant of IgG1 includes K97R, D239E, and / or L241M (shown underlined and in bold above), numbered in SEQ ID NO: 381. Within the full-length heavy chain constant region, these amino acid substitutions are numbered K214R, D356E, and L358M according to EU numbering. In some embodiments, the constant region of an anti-cleaved CDCP1 antibody (e.g., an anti-human truncated CDCP1 antibody) may further include one or more mutations or substitutions at amino acids L117, A118, G120, A213, and P214 (shown underlined above), numbered in SEQ ID NOs: 382, ​​383, and 384, or at L234, A235, G237, A330, and P331 according to EU numbering. In some embodiments, the constant region of an anti-cleaved CDCP1 antibody (e.g., an anti-human truncated CDCP1 antibody) may comprise one or more mutations or substitutions at amino acids L117A, A118E, G120A, A213S, and P214S, or L234A, L235E, G237A, A330S, and P331S according to EU numbering, of SEQ ID NO: 381. The constant region of an anti-cleaved CDCP1 antibody (e.g., an anti-human truncated CDCP1 antibody) may also comprise one or more mutations or substitutions at L117A, A118E, and G120A, or L234A, L235E, and G237A according to EU numbering, of SEQ ID NO: 381.

[0271] Alternatively, the VH domain of the anti-cleaved CDCP1 antibody (e.g., anti-human cleaved CDCP1) antibody may be a human IgG4 constant region, for example, the following human IgG4 amino acid sequence or a variant thereof: ASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNTKVDKRVESKYGPPCPSCPAPEFLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSLGK (SEQ ID NO: 385, containing S228P) The VH domain may comprise the amino acid sequence of any VH domain described herein fused to

[0272] The VL domains described herein can be fused to the constant domain of a human kappa or lambda light chain. For example, the VL domain of an anti-cleaved CDCP1 antibody (e.g., an anti-human cleaved CDCP1 antibody) can be fused to the constant domain of a human IgG1 kappa light chain amino acid sequence: RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 386) The VL domain may comprise the amino acid sequence of any of the VL domains described herein fused to

[0273] In some embodiments, the heavy chain constant region comprises a lysine or another amino acid at the C-terminus, e.g., it comprises the following last amino acid in the heavy chain: LSPGK (SEQ ID NO: 387). In some embodiments, the heavy chain constant region lacks one or more amino acids at the C-terminus, e.g., has the C-terminal sequence LSPG (SEQ ID NO: 388) or LSP (SEQ ID NO: 389).

[0274] Exemplary heavy and light chain amino acid sequences are described herein.

[0275] In some embodiments, an anti-cleaved CDCP1 antibody (e.g., an anti-human cleaved CDCP1 antibody) comprises a combination of heavy and light chain sequences described herein, e.g., in the previous paragraph, where the antibody comprises two heavy chains and two light chains and may further comprise at least one disulfide bond linking the two heavy chains together. The antibody may also comprise a disulfide bond linking each of the light chains to each of the heavy chains.

[0276] Heavy and light chains comprising amino acid sequences that are at least 99%, 98%, 97%, 96%, 95%, 90%, 85%, 80%, 75% or 70% identical to any of the heavy or light chains (or variable regions thereof) described herein can be used to generate anti-human truncated CDCP1 antibodies with desired characteristics, e.g., those described herein.

[0277] In some embodiments, the anti-cleaved CDCP1 antibodies (e.g., anti-human cleaved CDCP1 antibodies) described herein comprise a heavy chain variable region derived from a particular germline heavy chain immunoglobulin gene and / or a light chain variable region derived from a particular germline light chain immunoglobulin gene.

[0278] As used herein, a human antibody comprises heavy and light chain variable regions that are "the product of" or "derived from" particular germline sequences when the antibody variable regions are obtained from a system that uses human germline immunoglobulin genes. Such systems include immunizing transgenic mice carrying human immunoglobulin genes with the antigen of interest, or screening a human immunoglobulin gene library displayed on phage with the antigen of interest. A human antibody that is "the product of" or "derived from" a human germline immunoglobulin sequence can be identified as such by, for example, comparing the amino acid sequence of the human antibody with the amino acid sequences of human germline immunoglobulins and selecting the human germline immunoglobulin sequence whose sequence is most similar to that of the human antibody (i.e., has the highest percent identity). A human antibody that is "the product of" or "derived from" a particular human germline immunoglobulin sequence may contain amino acid differences when compared to the germline sequence, due, for example, to naturally occurring somatic mutations or the intentional introduction of site-specific mutations. However, the selected human antibody will typically be at least 90% identical in amino acid sequence to the amino acid sequence encoded by a human germline immunoglobulin gene and contain amino acid residues that identify the human antibody as human when compared to the germline immunoglobulin amino acid sequence of another species (e.g., a murine germline sequence). In some cases, a human antibody may be at least 95%, or even at least 96%, 97%, 98%, or 99% identical in amino acid sequence to the amino acid sequence encoded by the germline immunoglobulin gene. Typically, a human antibody derived from a particular human germline sequence will display no more than 10 amino acid differences from the amino acid sequence encoded by the human germline immunoglobulin gene. In certain cases, a human antibody may display no more than 5, or even no more than 4, no more than 3, no more than 2, or no more than 1 amino acid difference from the amino acid sequence encoded by the germline immunoglobulin gene.

[0279] The anti-cleaved CDCP1 antibody or antigen-binding fragment thereof may comprise a heavy chain variable region comprising CDR1, CDR2, and CDR3 sequences, and a light chain variable region comprising CDR1, CDR2, and CDR3 sequences, wherein one or more of these CDR sequences comprise a designated amino acid sequence based on the anti-cleaved CDCP1 antibody, antigen-binding fragment thereof described herein, or a conservatively modified form thereof, and wherein the antibody retains the desired functional properties of the anti-cleaved CDCP1 antibody described herein.

[0280] Conservative amino acid substitutions may be made in portions of an antibody other than or in addition to the CDRs. For example, conservative amino acid modifications may be made in the framework regions or Fc region. The variable region or heavy or light chain may contain 1, 2, 3, 4, 5, 1-2, 1-3, 1-4, 1-5, 1-10, 1-15, 1-20, 1-25, or 1-50 conservative amino acid substitutions compared to the anti-cleaved CDCP1 antibody sequences provided herein. In some embodiments, the anti-cleaved CDCP1 antibody, antigen-binding fragment thereof, contains a combination of conservative and non-conservative amino acid modifications.

[0281] Also provided are engineered and modified antibodies that can be prepared using an antibody having one or more of the VH and / or VL sequences disclosed herein as starting material to engineer a modified antibody, which can have altered properties from the starting antibody. Antibodies can be engineered by modifying one or more residues in one or both variable regions (i.e., VH and / or VL), e.g., in one or more CDR regions and / or in one or more framework regions. Additionally or alternatively, antibodies can be engineered by modifying residues in the constant region(s), e.g., to alter the effector function(s) of the antibody.

[0282] One type of variable region genetic engineering that can be performed is CDR grafting.Antibodies interact with target antigens mainly through the amino acid residues located in the six heavy and light chain complementarity determining regions (CDRs).Therefore, the amino acid sequences within CDRs are more diverse between individual antibodies than the sequences outside CDRs. Because CDR sequences are involved in most antibody-antigen interactions, it is possible to express recombinant antibodies that mimic the properties of a particular naturally occurring antibody by constructing expression vectors containing CDR sequences from that particular naturally occurring antibody grafted onto framework sequences from a different antibody with different properties (see, e.g., Riechmann, L. et al. (1998) Nature 332:323-327; Jones, P. et al. (1986) Nature 321:522-525; Queen, C. et al. (1989) Proc. Natl. Acad. Sci. USA 86:10029-10033; U.S. Patent No. 5,225,539 to Winter and U.S. Patent Nos. 5,530,101; 5,585,089; 5,693,762; and 6,180,370 to Queen et al.).

[0283] Accordingly, some embodiments described herein relate to isolated monoclonal antibodies or antigen-binding fragments thereof, comprising a heavy chain variable region comprising the CDR1, CDR2, and CDR3 sequences described herein, and a light chain variable region comprising the CDR1, CDR2, and CDR3 sequences described herein. Thus, such antibodies comprise the VH and VL CDR sequences of the monoclonal antibodies described herein, and may further comprise framework sequences that differ from these antibodies.

[0284] Such framework sequences can be obtained from public DNA databases or published references that contain germline antibody gene sequences. For example, germline DNA sequences of human heavy and light chain variable region genes are available in the "VBase" human germline sequence database (available on the Internet at www.mrc-cpe.cam.ac.uk / vbase), as well as in Kabat, EA, et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, US Department of Health and Human Services, NIH Publication No. 91-3242; Tomlinson, IM, et al. (1992) "The Repertoire of Human Germline V H Sequences Reveals about Fifty Groups of V H Segments with Different Hypervariable Loops" I. Mol. Biol. 227:776-798; and Cox, JPL et al. (1994) "A Directory of Human Germ-line V H "Segments Reveal a Strong Bias in Their Usage," Eur. J. Immunol. 24:827-836, the contents of each of which are expressly incorporated herein by reference.

[0285] In some embodiments, the framework sequences used in the anti-cleaved CDCP1 antibodies described herein are structurally similar to the framework sequences used by the anti-cleaved CDCP1 antibodies described herein.The VH CDR1, CDR2, and CDR3 sequences and the VL CDR1, CDR2, and CDR3 sequences can be grafted onto framework regions with the same sequences as those found in the germline immunoglobulin gene from which the framework sequences are derived, or the CDR sequences can be grafted onto framework regions that contain one or more mutations compared to the germline sequences.For example, in certain cases, it has been found to be beneficial to mutate residues in framework regions to maintain or enhance the antigen binding ability of antibodies (see, for example, U.S. Patent Nos. 5,530,101; 5,585,089; 5,693,762 and 6,180,370 to Queen et al.).

[0286] The engineered anti-cleaved CDCP1 antibodies described herein include those in which modifications have been made to framework residues within the VH and / or VL, for example, to improve the antibody's properties. Typically, such framework modifications are made to reduce the antibody's immunogenicity. For example, one approach is to "backmutate" one or more framework residues to the corresponding germline sequence. More specifically, an antibody that has undergone somatic mutation may contain framework residues that differ from the germline sequence from which the antibody is derived. Such residues can be identified by comparing the antibody framework sequence to the germline sequence from which the antibody is derived. Somatic mutations can be "backmutated" to the germline sequence, for example, by site-directed mutagenesis or PCR-mediated mutagenesis, to return the framework region sequences to their germline configuration. Such "backmutated" antibodies are also intended to be encompassed. Another type of framework modification involves mutating one or more residues within the framework region or even one or more CDR regions to remove T-cell epitopes, thereby reducing the antibody's potential immunogenicity. This approach is also referred to as "deimmunization" and is described in further detail in US Patent Publication No. 20030153043 by Carr et al.

[0287] Another type of variable region modification is to mutate amino acid residues within the VH and / or VL CDR1, CDR2, and / or CDR3 regions to thereby improve one or more binding characteristics (e.g., affinity) of the antibody of interest. Site-directed mutagenesis or PCR-mediated mutagenesis can be performed to introduce the mutation(s) and their effect on antibody binding or other functional properties of interest can be evaluated in in vitro or in vivo assays described herein and provided in the Examples. In some embodiments, conservative modifications (as discussed above) are introduced. Mutations can be amino acid substitutions, additions, or deletions. Furthermore, typically, no more than one, two, three, four, or five residues within the CDR regions are altered.

[0288] Methionine residues in the CDRs of an antibody can be oxidized, resulting in the possibility of chemical degradation and a resulting reduction in the efficacy of the antibody. Thus, anti-cleaved CDCP1 antibodies in which one or more methionine residues in the heavy and / or light chain CDRs are replaced with amino acid residues that are not susceptible to oxidative degradation are also provided. In some embodiments, the methionine residues in the CDRs of the anti-cleaved CDCP1 antibody or antigen-binding fragment thereof of the present disclosure are replaced with amino acid residues that are not susceptible to oxidative degradation.

[0289] Similarly, deamidated sites may also be removed from anti-truncated CDCP1 antibodies, particularly within the CDRs.

[0290] The cleavage-resistant CDCP1 variable regions described herein can be linked (e.g., covalently linked or fused) to an Fc, e.g., an IgG1, IgG2, IgG3, or IgG4 Fc, which can be of any allotype or isoallotype, e.g., for IgG1: G1m, G1m1(a), G1m2(x), G1m3(f), G1m17(z), for IgG2: G2m, G2m23(n), for IgG3: G3m, G3m21(g1), G3m28(g5), G3m1 l(b0), G3m5(b1), G3ml3(b3), G3ml4(b4), G3ml0(b5), G3ml5(s), G3ml6(t), G3m6(c3), G3m24(c5), G3m26(u), G3m27(v), where K may be: Km, Km1, Km2, Km3 (see, e.g., Jefferies et al. (2009) mAbs 1:1).

[0291] In general, the variable regions described herein may be linked to an Fc region that typically includes one or more modifications to alter one or more functional properties of the antibody, such as serum half-life, complement fixation, Fc receptor binding, antigen-dependent cellular cytotoxicity, and / or antigen-dependent cellular phagocytosis. Furthermore, the antibodies described herein may be chemically modified (e.g., one or more chemical moieties may be attached to the antibody) or modified to alter its glycosylation, thereby altering one or more functional properties of the antibody. Each of these aspects is described in detail below. The numbering of residues in the Fc region is that of the Kabat EU index.

[0292] The Fc region encompasses domains derived from the constant region of immunoglobulins, including fragments, analogs, variants, mutants, or derivatives of the constant region. Suitable immunoglobulins include IgG1, IgG2, IgG3, IgG4, and other classes such as IgA, IgD, IgE, and IgM. The constant region of an immunoglobulin is defined as a naturally occurring or synthetically produced polypeptide that is homologous to the C-terminal region of an immunoglobulin, and may include the CH1 domain, hinge, CH2 domain, CH3 domain, or CH4 domain, either individually or in combination.

[0293] Ig molecules interact with multiple classes of cell receptors. For example, IgG molecules interact with three classes of Fcγ receptors (FcγR), namely, FcγRI, FcγRII, and FcγRIII, which are specific for IgG class antibodies. It has been reported that the sequences important for IgG binding to FcγR receptors are located in the CH2 and CH3 domains. The serum half-life of an antibody is affected by its ability to bind to Fc receptors (FcRs).

[0294] In some embodiments, the Fc region is a variant Fc region, e.g., an Fc sequence that has been modified (e.g., by amino acid substitution, deletion, and / or insertion) to provide desirable structural properties and / or biological activity compared to a parent Fc sequence (e.g., an unmodified Fc polypeptide, which is subsequently modified to generate the variant).

[0295] Generally, a variant of a constant region or portion thereof, e.g., a CH1, CL, hinge, CH2, or CH3 domain, can contain 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more mutations and / or at most 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 mutation, or 1-10 or 1-5 mutations, or can comprise an amino acid sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to that of the corresponding wild-type region or domain (CH1, CL, hinge, CH2, or CH3 domain, respectively), provided that the heavy chain constant region containing the particular variant retains the required biological activity.

[0296] For example, modifications can be made within the Fc region to generate Fc variants that, compared to the parent Fc, (a) mediate increased or decreased antibody-dependent cell-mediated cytotoxicity (ADCC) and / or antibody-dependent cellular phagocytosis (ADCP), (b) mediate increased or decreased complement-mediated cytotoxicity (CDC), (c) have increased or decreased affinity for C1q, and / or (d) have increased or decreased affinity for Fc receptors. Such Fc region variants generally contain at least one amino acid modification in the Fc region. Combinations of amino acid modifications may be particularly desirable. For example, a variant Fc region may contain substitutions at two, three, four, five, etc., of the specific Fc region positions identified herein.

[0297] The variant Fc region may also contain sequence alterations in which amino acids involved in disulfide bond formation are removed or replaced with other amino acids. Such removal can avoid reaction with other cysteine-containing proteins present in the host cells used to produce the anti-cleaved CDCP1 antibodies described herein. Even when cysteine ​​residues are removed, the single-chain Fc domain can still form a dimeric Fc domain, which is held together noncovalently. In some embodiments, the Fc region may be modified to increase compatibility with a selected host cell. For example, the PA sequence near the N-terminus of a typical native Fc region may be removed, which can be recognized by digestive enzymes in E. coli, such as proline iminopeptidase. In some embodiments, one or more glycosylation sites within the Fc domain may be removed. Residues that are typically glycosylated (e.g., asparagine) may confer a cytolytic response. Such residues may be deleted or substituted with non-glycosylated residues (e.g., alanine). In some embodiments, sites involved in interaction with complement, such as the C1q binding site, may be removed from the Fc region. For example, the EKK sequence of human IgG1 may be deleted or substituted. In some embodiments, sites affecting binding to Fc receptors, preferably sites other than the salvage receptor binding site, may be removed. In some embodiments, the Fc region may be modified to remove ADCC sites. ADCC sites are known in the art; for example, see Molec. Immunol. 29 (5): 633-9 (1992) for the ADCC site in IgG1. Specific examples of mutant Fc domains are disclosed, for example, in WO97 / 34631, WO96 / 32478, and WO07 / 041635.

[0298] In some embodiments, the hinge region of an Fc is modified so that the number of cysteine ​​residues in the hinge region is altered, e.g., increased or decreased. This approach is further described in U.S. Patent No. 5,677,425 by Bodmer et al. The number of cysteine ​​residues in the hinge region of an Fc is altered, for example, to facilitate assembly of the light and heavy chains or to increase or decrease the stability of the antibody. In some embodiments, the Fc hinge region of an antibody is mutated to decrease the biological half-life of the antibody. More specifically, one or more amino acid mutations are introduced into the interface region of the CH2-CH3 domain of the Fc-hinge fragment so that the antibody has impaired Staphylococcus protein A (SpA) binding compared to the SpA binding of the native Fc-hinge domain. This approach is further described in U.S. Patent No. 6,165,745 by Ward et al.

[0299] In some embodiments, the Fc region is altered by substituting at least one amino acid residue with a different amino acid residue to alter the effector function of the antibody. For example, one or more amino acids selected from amino acid residues 234, 235, 236, 237, 297, 318, 320, 322, 330, and / or 331 can be substituted with a different amino acid residue so that the antibody has reduced affinity for an effector ligand but retains the antigen-binding ability of the parent antibody. The effector ligand for which affinity is altered can be, for example, an Fc receptor or the C1 component of complement. This approach is described in further detail in U.S. Patent Nos. 5,624,821 and 5,648,260, both by Winter et al.

[0300] In another example, one or more amino acids selected from amino acid residues 329, 331, and 322 can be replaced with a different amino acid residue such that the antibody has altered C1q binding and / or reduced or eliminated complement-dependent cytotoxicity (CDC). This approach is described in further detail in U.S. Patent No. 6,194,551 by Idusogie et al.

[0301] In another example, one or more amino acid residues within amino acid positions 231-239 are altered to thereby alter the ability of the antibody to fix complement. This approach is further described in PCT Publication WO 94 / 29351 by Bodmer et al.

[0302] In another example, the Fc region can be modified to enhance affinity for Fcγ and increase macrophage-mediated phagocytosis. See, e.g., Richard et al., Mo. Cancer. Ther. 7(8):2517-27 (2008), which is incorporated herein by reference in its entirety. In certain embodiments, the Fc region can be modified to increase affinity for FcγRIIa relative to inhibitory FcγRIIb. One particular point mutation, G236A (numbering according to the EU index), has been identified as having increased affinity for FcγRIIa relative to inhibitory FcγRIIb. This increased affinity for FcRIIa correlated with increased macrophage-mediated phagocytosis compared to native IgG1. In some embodiments, the Fc region of the anti-cleaved CDCP1 antibody comprises one or more mutations or a combination of mutations selected from G236A, I332E, S239 / I332E, I332E / G236A, and S239D / I332E / G236A. Other modifications to the Fc region may enhance antibody-dependent cellular cytotoxicity (ADCC), for example, by increasing affinity for activating receptors, such as FcγRI and / or FcγRIIIa. For example, the G236A substitution, as well as combinations of modifications that improve affinity for activating receptors (e.g., FcγRI and / or FcγRIIIa), including but not limited to substitutions at 332 and 239, result in substantially improved ADCC compared to the parent wild-type antibody. See U.S. Patent No. 9,040,041, which is incorporated herein by reference in its entirety.

[0303] In another embodiment, the Fc region comprises a nucleotide sequence selected from the group consisting of nucleotides at the following positions: 234, 235, 236, 238, 239, 240, 241, 243, 244, 245, 247, 248, 249, 252, 254, 255, 256, 258, 262, 263, 264, 265, 267, 268, 269, 270, 272, 276, 278, 280, 283, 285, 286, 289, 290, 292, 293, 294, 295, 296, 298, 299, 301, 303, 305, 307, 309, 312, 313, 315, 320 , 322, 324, 325, 326, 327, 329, 330, 331, 332, 333, 334, 335, 337, 338, 340, 360, 373, 376, 378, 382, ​​388, 389, 398, 414, 416, 419, 430, 433, 434, 435, 436, 437, 438, or 439 to reduce antibody-dependent cellular cytotoxicity (ADCC) and / or reduce affinity for Fcγ receptors. Exemplary substitutions include 236A, 239D, 239E, 268D, 267E, 268E, 268F, 324T, 332D, and 332E. Exemplary variants include 239D / 332E, 236A / 332E, 236A / 239D / 332E, 268F / 324T, 267E / 268F, 267E / 324T, and 267E / 268F / 324T. Other modifications to enhance FcγR and complement interactions include, but are not limited to, the substitutions 298A, 333A, 334A, 326A, 247I, 339D, 339Q, 280H, 290S, 298D, 298V, 243L, 292P, 300L, 396L, 305I, and 396L. These and other modifications are reviewed in Strohl (2009) Current Opinion in Biotechnology 20:685-691.

[0304] Fc modifications that enhance binding to Fcγ receptors include those at amino acid positions 238, 239, 248, 249, 252, 254, 255, 256, 258, 265, 267, 268, 269, 270, 272, 279, 280, 283, 285, 298, 289, 290, 292, 293, 294, 295, 296, 298, 301, 303, 305, 307, 312, 315, and 324 in the Fc region. , 327, 329, 330, 335, 337, 338, 340, 360, 373, 376, 379, 382, ​​388, 389, 398, 414, 416, 419, 430, 434, 435, 437, 438, or 439, where the numbering of the residues in the Fc region is that of the EU index in Kabat (WO 00 / 42072).

[0305] Optionally, the Fc region may include non-naturally occurring amino acid residues at additional and / or alternative positions known to those of skill in the art (see, e.g., U.S. Patent Nos. 5,624,821, 6,277,375, 6,737,056, 6,194,551, 7,317,091, 8,101,720, 9,040,041, PCX Patent Publications WO00 / 42072, WO01 (See WO04 / 058957, WO02 / 06919, WO04 / 016750, WO04 / 029207, WO04 / 035752, WO04 / 074455, WO04 / 099249, WO04 / 063351, WO05 / 070963, WO05 / 040217, WO05 / 092925, and WO06 / 020114).

[0306] The affinity and binding properties of an Fc region for its ligand can be determined by a variety of in vitro assay methods (biochemical or immunological-based assays) known in the art, including, but not limited to, equilibrium methods (e.g., enzyme-linked immunosorbent assay (ELISA) or radioimmunoassay (RIA)) or kinetics (e.g., BIACORE analysis) and other methods such as indirect binding assays, competitive inhibition assays, fluorescence resonance energy transfer (FRET), gel electrophoresis, and chromatography (e.g., gel filtration). These and other methods may utilize labels on one or more components being examined and / or may use various detection methods, including, but not limited to, chromatographic, fluorescent, luminescent, or isotopic labels. A detailed description of binding affinity and kinetics can be found in Paul, W. E., ed., Fundamental Immunology, 4th Ed., Lippincott-Raven, Philadelphia (1999), focusing on antibody-immunogen interactions.

[0307] In some embodiments, antibodies are modified to increase their biological half-life. Various approaches are possible. For example, this can be done by increasing the binding affinity of the Fc region to FcRn. For example, as described in U.S. Patent No. 6,277,375, one or more of the following residues can be mutated: 252, 254, 256, 433, 435, 436. Specific exemplary substitutions include one or more of the following: T252L, T254S, and / or T256F. Alternatively, to increase biological half-life, antibodies can be altered within the CH1 or CL regions to include salvage receptor binding epitopes derived from two loops of the CH2 domain of the IgG Fc region, as described in U.S. Patent Nos. 5,869,046 and 6,121,022 by Presta et al. Other exemplary variants that enhance binding to FcRn and / or improve pharmacokinetic properties include substitutions at positions 259, 308, 428, and 434, such as 359I, 308F, 428L, 428M, 434S, 4341 1, 434F, 434Y, and 434X1. Other exemplary variants that enhance binding to FcRn and / or improve pharmacokinetic properties include substitutions at positions 259, 308, 428, and 434, such as 3591, 308F, 428L, 428M, 434S, 4341 1, 434F, 434Y, and 434X1.Other mutations that increase Fc binding to FcRn include 250E, 250Q, 428L, 428F, 250Q / 428L (Hinton et al. 2004, J. Biol. Chem. 279(8): 6213-6216, Hinton et al. 2006 Journal of Immunology 176:346-356), 256A, 272A, 286A, 305A, 307A, 307Q, 311A, 312A, 376A, 378Q, 380A, 382A, and 434A (Shields et al., Journal of Biological Chemistry, 2001, 276(9):6591-6604), 252F, 252T, 252Y, 252W, 254T, 256S, 256R, 256Q, 256E, 256D, 256T, 309P, 311S, 433 R, 433S, 4331, 433P, 433Q, 434H, 434F, 434Y, 252Y / 254T / 256E, 433K / 434F / 436H, 308T / 309P / 311S (Dall Acqua et al. Journal of Immunology, 2002, 169:5171-5180, Dall'Acqua et al., 2006, Journal of Biological Chemistry 281:23514-23524). Other modifications to modulate FcRn binding are described in Yeung et al., 2010, J Immunol, 182:7663-7671.

[0308] In some embodiments, hybrid IgG isotypes with specific biological characteristics can be used. For example, IgG1 / IgG3 hybrid variants can be constructed by substituting IgG1 positions in the CH2 and / or CH3 regions with amino acids derived from IgG3 at positions where the two isotypes differ. In this way, hybrid variant IgG antibodies containing one or more substitutions, e.g., 274Q, 276K, 300F, 339T, 356E, 358M, 384S, 392N, 397M, 422I, 435R, and 436F, can be constructed. In some embodiments described herein, IgG1 / IgG2 hybrid variants can be constructed by substituting IgG2 positions in the CH2 and / or CH3 regions with amino acids derived from IgG1 at positions where the two isotypes differ. In this way, hybrid mutant IgG antibodies can be constructed that contain one or more substitutions, for example, one or more of the following amino acid substitutions: 233E, 234L, 235L, -236G (referring to the insertion of glycine at position 236), and 327A.

[0309] Furthermore, the binding sites for FcγRI, FcγRII, FcγRIII, and FcRn in human IgG1 have been mapped, and mutants with improved binding have been described (see Shields, RL et al., (2001) J. Biol. Chem. 276:6591-6604). Specific mutations at positions 256, 290, 298, 333, 334, and 339 have been shown to improve binding to FcγRIII. In addition, the combination mutants T256A / S298A, S298A / E333A, S298A / K224A, and S298A / E333A / K334A have been shown to improve FcγRIII binding and exhibit enhanced FcγRIIIa binding and ADCC activity (Shields et al., 2001). Other IgG1 mutants with strongly enhanced binding to FcγRIIIa have been identified, including mutants with S239D / I332E and S239D / I332E / A330L mutations, which showed the greatest increase in affinity for FcγRIIIa, reduced FcγRIIb binding, and potent cytotoxic activity in cynomolgus monkeys (Lazar et al., 2006). Introduction of triple mutations into antibodies such as alemtuzumab (CD52-specific), trastuzumab (HER2 / neu-specific), rituximab (CD20-specific), and cetuximab (EGFR-specific) translated into greatly enhanced ADCC activity in vitro, and the S239D / I332E mutant showed an enhanced ability to deplete B cells in monkeys (Lazar et al., 2006). Furthermore, in transgenic mice expressing human FcγRIIIa in models of B-cell malignancies and breast cancer, IgG1 mutants containing the L235V, F243L, R292P, Y300L, and P396L mutations were identified that showed enhanced binding to FcγRIIIa and concomitant enhanced ADCC activity ( Stavenhagen et al., 2007 , Nordstrom et al., 2011 ).Other Fc mutants that can be used include: S298A / E333A / L334A, S239D / I332E, S239D / I332E / A330L, L235V / F243L / R292P / Y300L / P396L and M428L / N434S.

[0310] Specific mutations at positions 234, 235, 236, 239, 267, 268, 293, 295, 324, 327, 328, 330, and 332 have been shown to improve binding to FcγRIIa and / or reduce binding to FcγRIIb, resulting in enhanced ADCC and / or ADCP activity (Richards et al., Mol. Cancer Ther. 7(8):2517-2527; US Patent No. 9,040,041). In particular, Fc variants that selectively improve binding to one or more human activating receptors relative to FcγRIIb, or that selectively improve binding to FcγRIIb relative to one or more activating receptors, may comprise a substitution selected from the group consisting of: 234G, 234I, 235D, 235E, 235I, 235Y, 236A, 236S, 239D, 267D, 267E, 267Q, 268D, 268E, 293R, 295E, 324G, 324I, 327H, 328A, 328F, 328I, 330I, 330L, 330Y, 332D, and 332E. Additional substitutions that can be further combined include other substitutions that modulate FcγR affinity and complement activity, including, but not limited to, 298A, 298T, 326A, 326D, 326E, 326W, 326Y, 333A, 333S, 334L, and 334A (U.S. Patent No. 6,737,056; Shields et al., Journal of Biological Chemistry, 2001, 276(9):6591-6604; U.S. Patent No. 6,528,624; Idusogie et al., 2001, J. Immunology 166:2571-2572). Preferred variants that may be particularly useful in combination with other Fc variants include those containing the substitutions 298A, 326A, 333A, and 334A. Additional substitutions that can be combined with FcγR-selective variants include 247L, 255L, 270E, 392T, 396L, and 421K (U.S. Application No. 10 / 754,922, U.S. Application No. 10 / 902,588), and 280H, 280Q, and 280Y (U.S. Application No. 10 / 370,749).

[0311] If an IgG4 constant domain is used, it may contain the substitution S228P, which mimics the hinge sequence in IgG1, thereby stabilizing the IgG4 molecule.

[0312] III. Antibody Physical Properties Anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof, such as those described herein, have some or all of the physical characteristics of the particular anti-cleaved CDCP1 antibodies described herein, e.g., the characteristics described in the Examples.

[0313] The anti-cleaved CDCP1 antibody or antigen-binding fragment thereof described herein may contain one or more glycosylation sites in either the light chain or heavy chain variable region. Such glycosylation sites may increase the immunogenicity of the antibody or alter the antibody's pK due to altered antigen binding (Marshall et al., (1972) Annu Rev Biochem 41:673-702; Gala and Morrison (2004) J. Immunol. 172:5489-94; Wallick et al., (1988) J Exp Med 168:1099-109; Spiro (2002) Glycobiology 12:43R-56R; Parekh et al., (1985) Nature 316:452-7; Mimura et al., (2000) Mol Immunol 37:697-706). Glycosylation is known to occur at motifs containing the NXS / T sequence. In some cases, the anti-cleaved CDCP1 antibody does not contain variable region glycosylation. This can be achieved by selecting an antibody that does not contain a glycosylation motif in the variable region or by mutating residues in the glycosylated region.

[0314] In some embodiments, the anti-cleaved CDCP1 antibody or antigen-binding fragment thereof has been modified to remove glycosylation sites. In some embodiments, removal of glycosylation sites is achieved through substitution of asparagine (N) with aspartic acid (D) at the position corresponding to residue 31 of SEQ ID NO: 61. In some embodiments, the antibody or antigen-binding fragment described herein comprises substitution of methionine (M) with alanine (A), isoleucine (I), leucine (L), or valine (V) at the position corresponding to residue 114 of SEQ ID NO: 61 or 65.

[0315] In some embodiments, the anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof described herein do not contain asparagine isomerization sites. Deamidation of asparagine can occur at NG or DG sequences, resulting in the generation of isoaspartic acid residues that introduce a kink into the polypeptide chain and reduce its stability (isoaspartic acid effect).

[0316] Each antibody has a unique isoelectric point (pi), which generally falls within the pH range of 6 to 9.5. The pi of IgG1 antibodies typically falls within the pH range of 7 to 9.5, and the pi of IgG4 antibodies typically falls within the pH range of 6 to 8. There is speculation that antibodies with pi outside the normal range may have some unfolding and instability under in vivo conditions. Therefore, anti-cleaved CDCP1 antibodies may contain pi values ​​that fall within the normal range. This can be achieved by selecting antibodies with pi in the normal range or by mutating charged surface residues.

[0317] Each antibody has a characteristic melting temperature, with a higher melting temperature indicating greater overall stability in vivo (Krishnamurthy R and Manning MC (2002) Curr Pharm Biotechnol 3:361-71). Mi (the temperature of initial unfolding) can be greater than 60° C., greater than 65° C., or greater than 70° C. The melting point of an antibody can be measured using differential scanning calorimetry (Chen et al., (2003) Pharm Res 20:1952-60; Ghirlando et al., (1999) Immunol Lett 68:47-52) or circular dichroism (Murray et al., (2002) J. Chromatogr Sci 40:343-9).

[0318] In some embodiments, antibodies are selected that do not rapidly degrade. Antibody degradation can be measured using capillary electrophoresis (CE) and MALDI-MS (Alexander AJ and Hughes DE (1995) Anal Chem 67:3626-32).

[0319] In some embodiments, antibodies are selected that have minimal aggregation effects, which can lead to the elicitation of unwanted immune responses and / or altered or unfavorable pharmacokinetic properties. Generally, antibodies are acceptable with aggregation of 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less. Aggregation can be measured by several techniques, including size exclusion column (SEC), high-performance liquid chromatography (HPLC), and light scattering. In some embodiments, the antibodies exhibit desirable solubility, e.g., solubility that allows for commercial production. In some embodiments, the solubility of the antibodies described herein was at least 10 mg / ml, at least 15 mg / ml, at least 20 mg / ml, at least 25 mg / ml, at least 30 mg / ml, at least 40 mg / ml, at least 50 mg / ml, at least 60 mg / ml, or at least 70 mg / ml at neutral or slightly acidic pH.

[0320] In some embodiments, the antibodies described herein have higher stability than the reference antibody. In some embodiments, the antibodies described herein have a higher melting temperature than the reference antibody. In some embodiments, the antibodies described herein have a lower tendency to aggregate than the reference antibody. In some embodiments, the antibodies described herein have higher solubility than the reference antibody. In some embodiments, the antibodies described herein have a higher absorption rate, lower toxicity, higher biological activity and / or target selectivity, better manufacturability, and / or lower immunogenicity than the reference antibody. The reference antibody can be, for example, another antibody or fragment thereof that binds to human truncated CDCP1, or a conjugate thereof.

[0321] In some aspects, an antibody or antigen-binding fragment thereof that specifically binds to a truncated CDCP1 described herein is less toxic than an antibody or antigen-binding fragment thereof that binds to full-length CDCP1 (e.g., human full-length CDCP1) at a detectable level.

[0322] IV. Methods for Genetically Engineering Antibodies As discussed above, new anti-cleaved CDCP1 antibodies can be generated using anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof having the VH and VL sequences disclosed herein by modifying the VH and / or VL sequences or the constant region(s) attached thereto. Thus, in another embodiment described herein, the structural features of the anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof described herein are used to generate structurally related anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof that retain at least one functional property of the anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof described herein, such as binding to human CDCP1 and cynomolgus monkey CDCP1. For example, one or more CDR regions of the anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof described herein can be recombinantly combined with known framework regions and / or other CDRs to generate additional recombinantly engineered anti-cleaved CDCP1 antibodies described herein, as discussed above. Other types of modifications include those described in the previous section. The starting material for the genetic engineering method is one or more of the VH and / or VL sequences provided herein, or one or more CDR regions thereof. To produce a genetically engineered antibody, it is not necessary to actually prepare (i.e., express) an antibody having one or more of the VH and / or VL sequences provided herein, or one or more CDR regions thereof. Rather, the information contained in the sequence(s) is used as a starting material to create "second-generation" sequence(s) derived from the original sequence(s), and then this "second-generation" sequence(s) is prepared and expressed as a protein.

[0323] Accordingly, provided herein are methods for preparing the anti-cleaved CDCP1 antibodies, antigen-binding fragments thereof, described herein.

[0324] The modified antibody may exhibit at least one of the functional properties described herein. The functional properties of the modified antibody can be assessed using standard assays available in the art and / or described herein, such as those described in the Examples (e.g., ELISA, FACS).

[0325] In some embodiments of the methods for genetically engineering anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof described herein, mutations can be introduced randomly or selectively along all or part of the anti-cleaved CDCP1 antibody or antigen-binding fragment coding sequence, and the resulting modified anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof can be screened for binding activity and / or other functional properties described herein. Mutation methods have been described in the art. For example, PCT Publication No. WO 02 / 092780 by Short describes methods for creating and screening antibody mutations using saturation mutagenesis, synthetic ligation assembly, or a combination thereof. Alternatively, PCT Publication No. WO 03 / 074679 by Lazar et al. describes methods for optimizing the physicochemical properties of antibodies using computational screening methods.

[0326] V. Nucleic acid molecules Another embodiment described herein relates to a nucleic acid molecule encoding an anti-cleaved CDCP1 antibody or antigen-binding fragment described herein. The nucleic acid may be present in whole cells, in a cell lysate, or in a partially purified or substantially pure form when purified from other cellular components or other contaminants, such as other cellular nucleic acids (e.g., other chromosomal DNA, e.g., chromosomal DNA naturally associated with the isolated DNA) or proteins, by standard techniques, including alkaline / SDS treatment, CsCl banding, column chromatography, restriction enzymes, agarose gel electrophoresis, and others known in the art. A nucleic acid may be "isolated" or "substantially purified." See F. Ausubel, et al., ed. (1987) Current Protocols in Molecular Biology, Greene Publishing and Wiley Interscience, New York. The nucleic acids described herein may be, for example, DNA or RNA, and may or may not contain intron sequences. In some embodiments, the nucleic acid is a cDNA molecule.

[0327] The nucleic acids described herein can be obtained using standard molecular biology techniques. For antibodies expressed by hybridomas (e.g., hybridomas prepared from transgenic mice carrying human immunoglobulin genes as described further below), cDNAs encoding the light and heavy chains of the antibodies produced by the hybridomas can be obtained by standard PCR amplification or cDNA cloning techniques. For antibodies obtained from an immunoglobulin gene library (e.g., using phage display technology), nucleic acids encoding the antibodies can be recovered from the library.

[0328] In some aspects, the polynucleotides described herein comprise nucleic acid molecules encoding the heavy chain variable region or heavy chain of an antibody or antigen-binding fragment thereof of the present disclosure.

[0329] In some embodiments, a nucleic acid molecule of the disclosure encodes a VH of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227, as shown in Table 7 below.

[0330] In some aspects, the polynucleotide comprises a nucleic acid molecule encoding the light chain variable region or light chain of an antibody or antigen-binding fragment thereof of the present disclosure.

[0331] In some embodiments, the nucleic acid molecule encodes a VL of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236, as shown in Table 7 below.

[0332] In some embodiments, a polynucleotide of the disclosure comprises a first nucleic acid molecule encoding a heavy chain variable region of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227, and a second nucleic acid molecule encoding a light chain variable region of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

[0333] In some embodiments, the mixture of polynucleotides of the present disclosure comprises a first polynucleotide comprising a nucleic acid molecule encoding a heavy chain variable region of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227, and a second polynucleotide comprising a nucleic acid molecule encoding a light chain variable region of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

[0334] Table 7: Variable heavy (VH) and variable light (VL) chain nucleic acid sequences of anti-human truncated CDCP1 antibodies [Table 17] [Table 18]

[0335] In some embodiments, the nucleic acid molecule encodes a VH of SEQ ID NO: 239, 243, 247, 249, 251, 253, 256, 258, 260, 262, 264, or 266, as shown in Table 8 below.

[0336] In some embodiments, the nucleic acid molecule encodes a VL of SEQ ID NO: 240, 244, or 250, as shown in Table 8 below.

[0337] Table 8: Variable heavy (VH) and variable light (VL) chain nucleic acid sequences of anti-mouse truncated CDCP1 antibodies [Table 19]

[0338] Nucleic acid molecules encoding VH and VL sequences homologous to those of the anti-cleaved CDCP1 antibodies and antigen-binding fragments thereof of the present disclosure are also provided herein. Exemplary nucleic acid molecules encode VH and VL sequences that are at least 70% identical, for example, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identical to the nucleic acid molecules encoding the VH and VL sequences of the anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof of the present disclosure (e.g., as shown in Tables 7 and 8 above). Furthermore, nucleic acid molecules with conservative substitutions (i.e., substitutions that do not change the resulting amino acid sequence upon translation of the nucleic acid molecule), for example, for codon optimization, are provided herein.

[0339] Also provided are nucleic acids encoding the VH and / or VL regions of anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof, e.g., the anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof described herein, which comprise a nucleotide sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to any of the nucleotide sequences encoding the VH and / or VL regions of the anti-cleaved CDCP1 antibodies or antigen-binding fragments described herein (e.g., shown in Tables 7 and 8 above).

[0340] Nucleic acids encoding the heavy and / or light chains of anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof, e.g., the anti-cleaved CDCP1 antibodies described herein, are also provided, which comprise a nucleotide sequence that is at least about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to any of the nucleotide sequences encoding the heavy and / or light chains of the anti-cleaved CDCP1 antibodies described herein.

[0341] Methods for producing the anti-cleaved CDCP1 antibodies or antigen-binding fragments thereof disclosed herein may include expressing the heavy and light chains in a cell line containing nucleotide sequences encoding the heavy and light chains along with signal peptides. Host cells containing these nucleotide sequences are encompassed herein.

[0342] Once the DNA fragments encoding the VH and VL segments are obtained, these DNA fragments can be further manipulated by standard recombinant DNA techniques to, for example, convert the variable region genes into full-length antibody chain genes, Fab fragment genes, or scFv genes. In these manipulations, the VL- or VH-encoding DNA fragment is operably linked to another DNA fragment encoding another protein, such as an antibody constant region or a flexible linker. As used in this context, the term "operably linked" shall mean that the two DNA fragments are joined such that the amino acid sequences encoded by the two DNA fragments remain in-frame.

[0343] The isolated DNA encoding the VH region can be converted into a full-length heavy chain gene by operably linking the VH-encoding DNA to another DNA molecule encoding a heavy chain constant region (hinge, CH1, CH2, and / or CH3). The sequences of human heavy chain constant region genes are known in the art (see, e.g., Kabat, EA, et al., (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, US Department of Health and Human Services, NIH Publication No. 91-3242), and DNA fragments encompassing these regions can be obtained by standard PCR amplification. The heavy chain constant region can be an IgG1, IgG2, IgG3, IgG4, IgA, IgE, IgM, or IgD constant region, e.g., an IgG2 and / or IgG4 constant region. For a Fab fragment heavy chain gene, the VH-encoding DNA can be operably linked to another DNA molecule encoding only the heavy chain CH1 constant region.

[0344] The isolated DNA encoding the VL region can be converted into a full-length light chain gene (as well as a Fab light chain gene) by operably linking the VL-encoding DNA to another DNA molecule encoding a light chain constant region, CL. The sequences of human light chain constant region genes are known in the art (see, for example, Kabat, EA, et al., (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, US Department of Health and Human Services, NIH Publication No. 91-3242), and DNA fragments encompassing these regions can be obtained by standard PCR amplification. The light chain constant region can be a kappa or lambda constant region.

[0345] To generate an scFv gene, a DNA fragment encoding the VH and VL is operably linked to another fragment encoding a flexible linker, for example, encoding the amino acid sequence (Gly4-Ser)3, so that the VH and VL sequences can be expressed as a contiguous single-chain protein with the VL and VH regions connected by the flexible linker (see, e.g., Bird et al., (1988) Science 242:423-426; Huston et al., (1988) Proc. Natl. Acad. Sci. USA 85:5879-5883; McCafferty et al., (1990) Nature 348:552-554).

[0346] In some aspects, the present disclosure provides a vector comprising an isolated nucleic acid molecule comprising a nucleotide sequence encoding an antibody or antigen-binding fragment thereof. In other aspects, the vector can be used in gene therapy.

[0347] Vectors suitable for the present disclosure include expression vectors, viral vectors, and plasmid vectors. In one aspect, the vector is a viral vector.

[0348] As used herein, an expression vector refers to any nucleic acid construct that, when introduced into an appropriate host cell, contains the necessary elements for transcription and translation of an inserted coding sequence, or, in the case of an RNA viral vector, the necessary elements for replication and translation. Expression vectors can include plasmids, phagemids, viruses, and derivatives thereof.

[0349] The expression vector of the present disclosure may contain a polynucleotide encoding an antibody or antigen-binding fragment thereof described herein. In one embodiment, the coding sequence of the antibody or antigen-binding fragment thereof is operably linked to an expression control sequence. As used herein, two nucleic acid sequences are operably linked when they are covalently linked in a manner that allows each component nucleic acid sequence to retain its functionality. A coding sequence and a gene expression control sequence are said to be operably linked when they are covalently linked in a manner that places the expression, transcription, and / or translation of the coding sequence under the influence or control of the gene expression control sequence. Two DNA sequences are said to be operably linked when induction of a promoter in a 5' gene expression sequence results in transcription of the coding sequence, and when the nature of the linkage between the two DNA sequences does not (1) result in the introduction of a frameshift mutation, (2) interfere with the ability of the promoter region to induce transcription of the coding sequence, or (3) interfere with the ability of the corresponding RNA transcript to be translated into a protein. Thus, a gene expression sequence is operably linked to a coding nucleic acid sequence if the gene expression sequence is capable of effecting transcription of the coding nucleic acid sequence and the resulting transcription product is translated into the desired antibody or antigen-binding fragment thereof.

[0350] Viral vectors include, but are not limited to, nucleic acid sequences derived from the following viruses: retroviruses, such as Moloney murine leukemia virus, Harvey murine sarcoma virus, mouse mammary tumor virus, and Rous sarcoma virus, lentiviruses, adenoviruses, adeno-associated viruses, SV40-type viruses, polyoma viruses, Epstein-Barr viruses, papilloma viruses, herpes viruses, vaccinia viruses, and polio viruses, as well as RNA viruses, such as retroviruses. Other vectors known in the art can be readily utilized. Certain viral vectors are based on non-cytopathic eukaryotic viruses in which non-essential genes have been replaced with genes of interest. Non-cytopathic viruses include retroviruses, whose life cycle involves reverse transcription of genomic viral RNA into DNA, followed by proviral integration into host cell DNA. Retroviruses have been approved for human gene therapy clinical trials. Retroviruses that are replication-deficient (i.e., capable of directing the synthesis of desired proteins but unable to manufacture infectious particles) are most useful. Such genetically altered retroviral expression vectors have general utility for highly efficient gene transduction in vivo. Standard protocols for producing replication-defective retroviruses (including the steps of incorporating exogenous genetic material into a plasmid, transfecting the plasmid into a packaging cell line, producing recombinant retrovirus by the packaging cell line, collecting viral particles from tissue culture medium, and infecting target cells with the viral particles) are provided in Kriegler, M., Gene Transfer and Expression, A Laboratory Manual, W.H. Freeman Co., New York (1990) and Murry, E.J., Methods in Molecular Biology, Vol. 7, Humana Press, Inc., Cliffton, NJ (1991).

[0351] Other vectors include plasmid vectors. Plasmid vectors have been widely described in the art and are well known to those skilled in the art. See, for example, Sambrook et al., Molecular Cloning: A Laboratory Manual, Second Edition, Cold Spring Harbor Laboratory Press, 1989. Over the past few years, plasmid vectors have been found to be particularly useful for delivering genes to cells in vivo due to their inability to replicate and integrate into the host genome. These plasmids, however, have a promoter compatible with the host cell and can express peptides from genes operably encoded within the plasmid. Some widely used plasmids available from commercial suppliers include pBR322, pUC18, pUC19, various pcDNA plasmids, pRC / CMV, various pCMV plasmids, pSV40, and pBlueScript. Further examples of specific plasmids include pcDNA3.1, catalog number V79020; pcDNA3.1 / hygro, catalog number V87020; pcDNA4 / myc-His, catalog number V86320; and pBudCE4.1, catalog number V53220, all from Invitrogen (Carlsbad, CA). Other plasmids are well known to those skilled in the art. Furthermore, plasmids can be custom designed to remove and / or add specific fragments of DNA using standard molecular biology techniques.

[0352] VI. Antibody production An antibody or fragment thereof that specifically binds to a truncated CDCP1 (e.g., a human or mouse truncated CDCP1) can be produced by any method known in the art for synthesizing antibodies, such as chemical synthesis or recombinant expression technology. The methods described herein utilize, unless otherwise indicated, conventional techniques within the skill of those of ordinary skill in the art of molecular biology, microbiology, genetic analysis, recombinant DNA, organic chemistry, biochemistry, PCR, oligonucleotide synthesis and modification, nucleic acid hybridization, and related fields. These techniques are described, for example, in the references cited herein and are explained in detail therein.For example, see Maniatis T et al., (1982) Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Sambrook J et al., (1989), Molecular Cloning: A Laboratory Manual, Second Edition, Cold Spring Harbor Laboratory Press, Sambrook J et al., (2001) Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, Ausubel FM et al., Current Protocols in Molecular Biology, John Wiley & Sons (1987 and annual updates), Current Protocols in Immunology, John Wiley & Sons (1987 and annual updates) Gait (ed.) (1984) Oligonucleotide Synthesis: A Practical Approach, IRL Press, Eckstein (ed.) (1991) Oligonucleotides and Analogues: A Practical Approach, IRL Press; Birren B et al., (eds.) (1999) Genome Analysis: A Laboratory Manual, Cold Spring Harbor Laboratory Press.

[0353] In specific embodiments, the antibodies described herein are antibodies (e.g., monoclonal antibodies) that are prepared, expressed, produced, or isolated by any means that involves production, e.g., through synthesis, genetic engineering of DNA sequences. In certain embodiments, such antibodies comprise sequences (e.g., DNA sequences or amino acid sequences) that do not naturally occur within the antibody germline repertoire of an animal or mammal (e.g., a human) in vivo.

[0354] In certain aspects, provided herein is a method for producing an antibody or antigen-binding fragment thereof that specifically binds to a truncated CDCP1 (e.g., a human or mouse truncated CDCP1), the method comprising culturing a cell or host cell described herein. In certain aspects, provided herein is a method for producing an antibody or antigen-binding fragment thereof that specifically binds to a truncated CDCP1 (e.g., a human or mouse truncated CDCP1), the method comprising expressing (e.g., recombinantly expressing) the antibody or antigen-binding fragment thereof using a cell or host cell described herein (e.g., a cell or host cell comprising a polynucleotide encoding an antibody described herein). In certain aspects, the cell is an isolated cell. In certain aspects,...

Claims

1. An isolated antibody or antigen-binding fragment thereof that specifically binds to truncated human complement C1r / C1s, Uegf, Bmp1 (CUB) domain-containing protein 1 (CDCP1), and preferentially binds to truncated CDCP1.

2. The antibody or antigen-binding fragment thereof of claim 1, which does not bind to full-length human CDCP1 at a detectable level.

3. The antibody or antigen-binding fragment thereof of claim 1 or 2, wherein the binding between the antibody or antigen-binding fragment thereof and truncated CDCP1 or full-length CDCP1 is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

4. The antibody or antigen-binding fragment thereof of claim 1 or 2, wherein the truncated CDCP1 comprises a first cleavage domain and a second cleavage domain, and the first cleavage domain and the second cleavage domain are not linked.

5. The antibody or antigen-binding fragment thereof of claim 1 or 2, wherein the truncated CDCP1 comprises a membrane-bound complex.

6. The antibody or antigen-binding fragment thereof of claim 4, wherein the first truncated domain consists of the amino acid sequence set forth in SEQ ID NO: 63, 68, or 74.

7. The antibody or antigen-binding fragment thereof according to claim 1 or 2, wherein the second truncated domain consists of the amino acid sequence set forth in SEQ ID NO: 64, 70, or 77.

8. The antibody or antigen-binding fragment thereof of claim 1 or 2, wherein the truncated CDCP1 is generated by truncating at residues K365, R368, and / or K369 of SEQ ID NO:

273.

9. The antibody or antigen-binding fragment thereof of claim 1 or 2, wherein the truncated CDCP1 is post-translationally modified, and the post-translational modifications include phosphorylation and N-linked glycosylation.

10. An isolated antibody or antigen-binding fragment thereof that specifically binds to a truncated human CDCP1 and comprises a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises a VL complementarity determining region (CDR) 1, a VL-CDR2, and a VL-CDR3, and the VH comprises any of the sequences set forth in SEQ ID NOs: 1 (SVSSAVA), 2 (SASSLY), 268 (SX １ X ２ X ３ X ４ X ５ ), 269 (X ６ FSSSX ７ SI), 270 (SIYPYSGSTX ８ ), and 271 (X ９ X １０ X １２ S.X. １２ YSHTWWVSYGX １３ ) or 272(X １４ YWVX １５ FWYGHFSYYRPAL), X １ = glycine (G), serine (S), methionine (M), leucine (L), valine (V), or arginine (R); X ２ = glutamine (Q), serine (S), glutamic acid (E), asparagine (N), lysine (K), proline (P), arginine (R), leucine (L), or histidine (H); X ３ = arginine (R), serine (S), valine (V), tryptophan (W), leucine (L), lysine (K), methionine (M), glutamine (Q), or proline (P); X ４ = proline (P), leucine (L), threonine (T), or serine (S); X ５ = isoleucine (I), alanine (A), methionine (M), lysine (K), valine (V), leucine (L), phenylalanine (F), X ６ = no amino acid, aspartic acid (D), or asparagine (N), X ７ = serine (S) or tyrosine (Y), X ８ = serine (S) or tyrosine (Y), X ９ = glutamine (Q), arginine (R), or lysine (K); X １０ = serine (S), asparagine (N), threonine (T), glycine (G), alanine (A), or aspartic acid (D); X １１ = glutamine (Q) or histidine (H), X １２ = tyrosine (Y) or phenylalanine (F), X １３ = methionine (M), alanine (A), isoleucine (I), leucine (L), or valine (V); X １４ = threonine (T) or isoleucine (I), X １５ = glutamine (Q) or aspartic acid (D); An isolated antibody or antigen-binding fragment thereof.

11. 1. An isolated antibody or antigen-binding fragment thereof that specifically binds to a truncated human CDCP1, comprising a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises a VL complementarity determining region (CDR) 1 sequence of SEQ ID NO: 1 (SVSSAVA), a VL-CDR2 sequence of SEQ ID NO: 2 (SASSLY), and a VL-CDR3 sequence of SEQ ID NO: 8 (TGQRPM), 23 (FMRPAF), 16 (TAQSPL), 11 (VELVPM), 12 (AGKRPL), or 14 (LGVRAA), respectively; and the VH comprises a VL complementarity determining region (CDR) 1 sequence of SEQ ID NO: 1 (SVSSAVA), a VL-CDR2 sequence of SEQ ID NO: 2 (SASSLY), and a VL-CDR3 sequence of SEQ ID NO: 8 (TGQRPM), 23 (FMRPAF), 16 (TAQSPL), 11 (VELVPM), 12 (AGKRPL), or 14 (LGVRAA), respectively. １ FSSSX ２ VH-CDR1 sequence of SEQ ID NO: 270 (SIYPYSGSTX) ３ ) and the VH-CDR2 sequence of SEQ ID NO: 271 (X ４ X ５ X ６ S.X. ７ YSHTWWVSYGX ８ ) or SEQ ID NO: 272 (X ９ YWVX １０ FWYGHFSYYRPAL), X １ = no amino acid, aspartic acid (D), or asparagine (N), X ２ = serine (S) or tyrosine (Y), X ３ = serine (S) or tyrosine (Y), X ４ = glutamine (Q), arginine (R), or lysine (K); X ５ = serine (S), asparagine (N), threonine (T), glycine (G), alanine (A), or aspartic acid (D); X ６ = glutamine (Q) or histidine (H), X ７ = tyrosine (Y) or phenylalanine (F), X ８ = methionine (M), alanine (A), isoleucine (I), leucine (L), or valine (V); X ９ = threonine (T) or isoleucine (I), X １０ = glutamine (Q) or aspartic acid (D); An isolated antibody or antigen-binding fragment thereof.

12. An isolated antibody or antigen-binding fragment thereof that specifically binds to a truncated human CDCP1, comprising a light chain variable region (VL) and a heavy chain variable region (VH), wherein the VL comprises a VL complementarity determining region (CDR) 1, a VL-CDR2, and a VL-CDR3, the VH comprises a VH-CDR1, a VH-CDR2, and a VH-CDR3, and the VL-CDR3 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 3-25.

13. The antibody or antigen-binding fragment thereof of claim 12, wherein VL-CDR2 comprises the amino acid sequence of SEQ ID NO:

2.

14. The antibody or antigen-binding fragment thereof according to claim 12 or 13, wherein VL-CDR1 comprises the amino acid sequence of SEQ ID NO:

1.

15. The antibody or antigen-binding fragment thereof according to claim 12 or 13, wherein VH-CDR1 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 26-29, 109, and 111.

16. The antibody or antigen-binding fragment thereof according to claim 12 or 13, wherein VH-CDR2 comprises the amino acid sequence of SEQ ID NO: 30 or 31.

17. The antibody or antigen-binding fragment thereof according to claim 12 or 13, wherein VH-CDR3 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 20, 32-47, and 105.

18. (a) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:32; (b) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:33; (c) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:34; (d) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:35, or (e) VL-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:1, VL-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:2, VL-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:3, VH-CDR1 comprises the amino acid sequence set forth in SEQ ID NO:26, VH-CDR2 comprises the amino acid sequence set forth in SEQ ID NO:30, and VH-CDR3 comprises the amino acid sequence set forth in SEQ ID NO:36; An antibody or antigen-binding fragment thereof according to claim 12 or 13.

19. The antibody or antigen-binding fragment thereof of claim 12 or 13, wherein the VH comprises an amino acid sequence having at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 61, 65, 67, 69, 71, 73, 75, 79, 80, 81, 82, 83, 84, 85, 86, 87, 89, 91, 99, 103, 107, 123, and 133.

20. The antibody or antigen-binding fragment thereof of claim 12 or 13, wherein the VH comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 61, 65, 67, 69, 71, 73, 75, 79, 80, 81, 82, 83, 84, 85, 86, 87, 89, 91, 99, 103, 107, 123, and 133.

21. 14. The antibody or antigen-binding fragment thereof of claim 12 or 13, wherein the VL comprises an amino acid sequence having at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOs: 62, 76, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, and 132.

22. 14. The antibody or antigen-binding fragment thereof of any one of claims 10 to 13, wherein the VL comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 62, 76, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, and 132.

23. (a) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:61, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (b) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (c) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:67, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (d) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:69, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (e) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 71, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (f) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 73, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (g) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 75, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (h) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 79, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (i) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (j) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 83, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (k) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 85, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (l) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 87, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (m) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 89, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (n) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 91, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (o) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 94; (p) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:96; (q) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:98; (r) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 100; (s) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 102; (t) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 103, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 104; (u) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 106; (v) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 108; (w) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 110; (x) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:112; (y) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 114; (aa) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 116; (bb) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 118; (cc) the VH comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL comprises the amino acid sequence set forth in SEQ ID NO:120; (dd) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 122; (ee) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 123, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 124; (ff) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 126; (gg) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 128; (hh) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 130; (ii) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 132; or (jj) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 133, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (kk) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 80, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (ll) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 81, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (mm) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 82, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (nn) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 84, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; or (oo) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 86, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; An antibody or antigen-binding fragment thereof according to claim 12 or 13.

24. An isolated antibody or antigen-binding fragment thereof that specifically binds to the same truncated human CDCP1 epitope as a reference antibody comprising a heavy chain variable region (VH) and a light chain variable region (VL), (a) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:61, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (b) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (c) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:67, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (d) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:69, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (e) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 71, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (f) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 73, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (g) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 75, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (h) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 79, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (i) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (j) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 83, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (k) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 85, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (l) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 87, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (m) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 89, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (n) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 91, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (o) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:94; (p) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 96; (q) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:98; (r) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 100; (s) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 102; (t) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 103, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 104; (u) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 106; (v) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 108; (w) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 110; (x) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:112; (y) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 114; (aa) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 116; (bb) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 118; (cc) the VH comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL comprises the amino acid sequence set forth in SEQ ID NO:120; (dd) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 122; (ee) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 123, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 124; (ff) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 126; (gg) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 128; (hh) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 130; (ii) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 132; or (jj) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 133, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (kk) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 80, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (ll) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 81, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (mm) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 82, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (nn) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 84, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; or (oo) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 86, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (kk) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 80, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (ll) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 81, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (mm) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 82, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (nn) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 84, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; or (oo) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 86, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; An isolated antibody or antigen-binding fragment thereof.

25. 1. An isolated antibody or antigen-binding fragment thereof that cross-competes with a reference antibody comprising a heavy chain variable region (VH) and a light chain variable region (VL) for binding to a truncated human CDCP1 epitope, (a) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:61, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (b) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (c) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:67, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (d) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:69, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:62; (e) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 71, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (f) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 73, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (g) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 75, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (h) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 79, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (i) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (j) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 83, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (k) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 85, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (l) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 87, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (m) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 89, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (n) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 91, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (o) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 94; (p) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:96; (q) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:98; (r) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 100; (s) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 102; (t) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 103, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 104; (u) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 106; (v) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 108; (w) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 110; (x) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO:112; (y) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 114; (aa) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 116; (bb) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 118; (cc) the VH comprises the amino acid sequence set forth in SEQ ID NO:65, and the VL comprises the amino acid sequence set forth in SEQ ID NO:120; (dd) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 122; (ee) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 123, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 124; (ff) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 107, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 126; (gg) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 128; (hh) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 99, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 130; (ii) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 65, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 132; or (jj) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 133, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 76; (kk) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 80, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (ll) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 81, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (mm) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 82, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; (nn) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 84, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; or (oo) the VH of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 86, and the VL of the reference antibody comprises the amino acid sequence set forth in SEQ ID NO: 62; An isolated antibody or antigen-binding fragment thereof.

26. The antibody or antigen-binding fragment thereof, (a) the antibody inhibits tumor growth and / or metastasis; (b) the antibody reduces tumor volume; (c) the antibody increases progression-free survival; (d) the antibody increases overall survival; (e) the antibody promotes CDCP1 internalization and / or degradation; and (f) any combination of these 26. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, having one or more properties selected from the group consisting of:

27. The antibody or antigen-binding fragment thereof is about 1×10 －４ K below M Ｄ , specifically binds to truncated human CDCP1, and Ｄ The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, wherein is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

28. The antibody or antigen-binding fragment thereof is about 1×10 －４ On-rate (k ｏｎ ) specifically binds to truncated human CDCP1, k ｏｎ The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, wherein the rate is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

29. The antibody or antigen-binding fragment thereof is about 1×10 －４ Off-rate (k ｏｆｆ ) specifically binds to truncated human CDCP1, k ｏｆｆ The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, wherein is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

30. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, wherein the antibody or antigen-binding fragment thereof binds to a truncated cynomolgus CDCP1.

31. 26. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, wherein the antibody or antigen-binding fragment is selected from the group consisting of IgG1, IgG2, IgG3, IgG4, or variants thereof.

32. 26. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, which is an IgG1 antibody.

33. 26. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, which has been modified to remove glycosylation sites.

34. 34. The antibody or antigen-binding fragment thereof of claim 33, wherein the glycosylation site removal is achieved through substitution of asparagine (N) with aspartic acid (D) at the position corresponding to residue 31 of SEQ ID NO:

61.

35. 26. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, comprising a substitution of methionine (M) at a position corresponding to residue 114 of SEQ ID NO: 61 or 65 with alanine (A), isoleucine (I), leucine (L), or valine (V).

36. 26. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, which is a human, humanized, or chimeric antibody, or an antigen-binding fragment thereof.

37. 26. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, suitable for administration to a human subject.

38. The antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24 and 25, which is a full-length antibody.

39. 26. The antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, which is an antigen-binding fragment.

40. Fab, Fab', F(ab') ２ , single chain Fv (scFv), disulfide-linked Fv, IgNar, intrabody, IgGΔCH2, minibody, F(ab′) ３ , tetrabodies, triabodies, diabodies, single domain antibodies, DVD-Ig, Fcab, mAb ２ , (scFv) ２ 40. The antigen-binding fragment of claim 39, which is an scFv-Fc or an scFv-Fc.

41. A bispecific antibody comprising an antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24 and 25.

42. A bispecific antibody comprising an antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, or a multispecific antibody comprising an antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25.

43. An antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, a bispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, or a bispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, or a multispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, further comprising a detectable label.

44. A polynucleotide or a set of polynucleotides encoding an antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, a bispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, or a bispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, or a multispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25.

45. A polynucleotide comprising a nucleic acid molecule encoding the heavy chain variable region or heavy chain of the antibody or antigen-binding fragment thereof of any one of claims 10-13, 24, and 25.

46. 46. ​​The polynucleotide of claim 45, wherein the nucleic acid molecule encodes a VH of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227.

47. A polynucleotide comprising a nucleic acid molecule encoding the light chain variable region or light chain of the antibody or antigen-binding fragment thereof of any one of claims 10-13, 24, and 25.

48. 48. The polynucleotide of claim 47, wherein the nucleic acid molecule encodes a VL of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

49. 20. A polynucleotide comprising: a first nucleic acid molecule encoding a heavy chain variable region of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227; and a second nucleic acid molecule encoding a light chain variable region of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

50. 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227, and a second polynucleotide comprising a nucleic acid molecule encoding a light chain variable region of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

51. A polynucleotide comprising a nucleic acid molecule encoding a heavy chain variable region or heavy chain of the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, and a light chain variable region or light chain of the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25.

52. A vector comprising the polynucleotide of claim 48.

53. (a) an antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, (b) a bispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, (c) a bispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, or a multispecific antibody comprising the antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25, (d) a polynucleotide according to claim 48, (e) a vector comprising the polynucleotide according to claim 48, or (f) a polynucleotide comprising a nucleic acid molecule encoding a heavy chain variable region or a heavy chain of the antibody or antigen-binding fragment thereof according to any one of claims 10-13, 24, and 25, or a polynucleotide comprising a nucleic acid molecule encoding a light chain variable region or a light chain of the antibody or antigen-binding fragment thereof according to any one of claims 10-13, 24, and 25. A polynucleotide comprising a first vector and a nucleic acid molecule encoding a heavy chain variable region or heavy chain of the antibody or antigen-binding fragment thereof according to any one of claims 10-13, 24, and 25, wherein the nucleic acid molecule encodes a VH of SEQ ID NO: 88, 92, 93, 95, 97, 163, 165, 169, 171, 173, 175, 177, 181, 183, 187, 189, 191, 193, 195, 203, 207, 211, or 227. A host cell comprising a second vector comprising a polynucleotide comprising a nucleic acid molecule encoding a light chain variable region or light chain of the antibody or antigen-binding fragment thereof described in any one of claims 3, 24, and 25, wherein the nucleic acid molecule encodes a VL of SEQ ID NO: 90, 164, 166, 180, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, or 236.

54. E. coli, Pseudomonas, Bacillus, Streptomyces, yeast, HPAC, PL5, PL45, HPNE, Expi293F human cells, C6 (rat glioma cell line), U2OS, Chem-1, CHO, YB / 20, NS0, PER-C6, HEK-293T, HEK293T-cCDCP1, NIH-3T3, HeLa, BHK, Hep G2, SP2 / 0, R1.1, B-W, L-M, COS1, COS7, BSC1, BSC40, BMT10 cells, PANC-1, Panc 03.27, Hs766T, CFPAC-1, CAPAN-1, Mia 54. The host cell of claim 53, selected from the group consisting of PaCa-2, CAPAN-2, BXPC3, mouse Fc1245, mouse Fc1242, mouse Fc1245-cCDCP1, mouse PyMT, mouse P53, mouse 4T1, mouse EMT6, mouse TRAMP, mouse C2, mouse MC38, mouse CT26, a plant cell, an insect cell, and a human cell.

55. An immunoconjugate comprising the antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, and a therapeutic agent.

56. The immunoconjugate of claim 55, wherein the therapeutic agent is selected from the group consisting of a cytotoxin, a non-cytotoxic drug, a radioactive agent, a second antibody, an enzyme, an anti-neoplastic agent, and any combination thereof.

57. A method for producing an antibody or antigen-binding fragment thereof that binds to a truncated human CDCP1, comprising culturing the host cell described in claim 53 so that the nucleic acid molecule is expressed and the antibody or antigen-binding fragment thereof is produced.

58. 58. The method of claim 57, further comprising isolating the antibody or antigen-binding fragment thereof from the culture.

59. 49. An isolated antibody or antigen-binding fragment thereof that specifically binds to a truncated human CDCP1 and is encoded by the polynucleotide of claim 48.

60. A pharmaceutical composition comprising the antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25, and a pharma- ceutically acceptable excipient.

61. 61. The pharmaceutical composition of claim 60, formulated for intravenous, intraperitoneal, intramuscular, intraarterial, intrathecal, intralymphatic, intralesional, intracapsular, intraorbital, intracardiac, intradermal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal, epidural, intrasternal, topical, epidermal, or mucosal administration.

62. A composition for treating cancer in a subject in need thereof, comprising the antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25.

63. The composition of claim 62, wherein administration of the antibody or antigen-binding fragment thereof reduces or inhibits metastasis of the cancer in the subject.

64. A composition for reducing or inhibiting metastasis of cancer in a subject in need thereof, comprising an antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24, and 25.

65. 65. The composition of claim 64, wherein the subject is suffering from cancer.

66. The composition of claim 62, wherein the cancer has a truncated CDCP1 present on the cancer cell surface.

67. 63. The composition of claim 62, wherein the cancer comprises a tumor.

68. Cancers include small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC), squamous NSCLC, non-squamous NSCLC, glioma, gastrointestinal cancer, kidney cancer, clear cell carcinoma, ovarian cancer, liver cancer, colorectal cancer, endometrial cancer, kidney cancer, renal cell carcinoma (RCC), prostate cancer, hormone refractory prostate adenocarcinoma, thyroid cancer, neuroblastoma, pancreatic cancer, glioblastoma (glioma polymorphism), cervical cancer, gastric cancer, bladder cancer, hepatocellular carcinoma (hepatocellular carcinoma), breast cancer, colon cancer, head and neck cancer (or cancer), head and neck squamous cell carcinoma (HNSCC), gastric cancer, germ cell tumors, childhood sarcoma, sinonasal natural Killer, melanoma, metastatic melanoma, cutaneous or intraocular melanoma, mesothelioma, bone cancer, skin cancer, uterine cancer, cancer of the anal region, testicular cancer, cancer of the fallopian tubes, cancer of the endometrium, cancer of the cervix, cancer of the vagina, cancer of the vulva, cancer of the esophagus, cancer of the small intestine, cancer of the endocrine system, cancer of the parathyroid gland, cancer of the adrenal gland, soft tissue sarcoma, cancer of the urethra, cancer of the penis, solid tumors of childhood, cancer of the ureter, cancer of the renal pelvis, neoplasms of the central nervous system (CNS), primary CNS lymphoma, tumor angiogenesis, spinal axis tumors, brain cancer, brain stem glioma, pituitary adenoma, Kaposi's sarcoma, epidermoid carcinoma, squamous cell carcinoma, asbestos-induced Environmentally induced cancers, including those induced by the immune system, virus-associated cancers or cancers of viral origin, tumors associated with or of human papillomavirus (HPV) origin, acute leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myelogenous leukemia (CML), anaplastic AML, myeloblastic leukemia, myeloblastic leukemia, promyelocytic leukemia, myelomonocytic leukemia, monocytic leukemia, erythroleukemia, megakaryoblastic leukemia, solitary granulocytic sarcoma, chloroma, Hodgkin's lymphoma (HL), non-Hodgkin's lymphoma (NHL), B-cell lymphoma, T-cell lymphoma, ... lymphoplasmocytic lymphoma, monocytoid B-cell lymphoma, mucosa-associated lymphoid tissue (MALT) lymphoma, anaplastic large cell lymphoma, adult T-cell lymphoma / leukemia, mantle cell lymphoma, angioimmunoblastic T-cell lymphoma, hemangiocentric lymphoma, intestinal T-cell lymphoma, primary mediastinal B-cell lymphoma, precursor T-lymphoblastic lymphoma, T-lymphoblastic, peripheral T-cell lymphoma, lymphoblastic lymphoma, post-transplant lymphoproliferative disorder, true histiocytic lymphoma, primary central nervous system lymphoma, primary effusion lymphoma, lymphoblastic lymphoma (LBL), hematopoietic tumors of the lymphoid lineage,63. The composition of claim 62, wherein the cancer is selected from the group consisting of acute lymphoblastic leukemia, diffuse large B-cell lymphoma, Burkitt's lymphoma, follicular lymphoma, diffuse histiocytic lymphoma (DHL), immunoblastic large cell lymphoma, precursor B-lymphoblastic lymphoma, cutaneous T-cell lymphoma (CTLC), lymphoplasmacytic lymphoma with Waldenstrom's macroglobulinemia (LPL), myeloma, IgG myeloma, light chain myeloma, non-secretory myeloma, smoldering myeloma (indolent myeloma), solitary plasmacytoma, multiple myeloma, chronic lymphocytic leukemia (CLL), hairy cell lymphoma, and any combination of the above cancers.

69. A composition for killing tumor cells in a subject in need thereof, comprising the antibody or antigen-binding fragment thereof of any one of claims 1, 2, 10-13, 24, and 25.

70. 70. The composition of claim 69, wherein the tumor cell is metastatic.

71. 63. The composition of claim 62, further comprising administering to the subject an additional anti-cancer therapy.

72. 72. The composition of claim 71, wherein the additional anti-cancer therapy comprises chemotherapy, immunotherapy, surgery, radiation therapy, or any combination thereof.

73. 72. The composition of claim 71, wherein the additional anti-cancer therapy comprises a standard of care therapy.

74. 72. The composition of claim 71, wherein the additional anti-cancer therapy comprises a checkpoint inhibitor.

75. Additional anti-cancer therapies include those targeting inducible T-cell costimulatory factor (ICOS), CD137 (4-1BB), CD134 (OX40), NKG2A, CD27, CD96, glucocorticoid-induced TNFR-related protein (GITR), and herpes virus entry mediator (HVEM), programmed death-1 (PD-1), programmed death ligand-1 (PD-L1), CTLA-4, B- and T-lymphocyte attenuating factor (BTLA), T-cell immunoglobulin and mucin domain-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), adenosine A2a receptor (A2aR).

72. The composition of claim 71, comprising an antibody or antigen-binding fragment thereof that specifically binds to a protein selected from killer cell lectin-like receptor G1 (KLRG-1), natural killer cell receptor 2B4 (CD244), CD160, T cell immunoreceptor with Ig and ITIM domains (TIGIT), and receptor for V-domain Ig suppressor of T cell activation (VISTA), KIR, TGFβ, IL-10, IL-8, B7-H4, Fas ligand, CXCR4, mesothelin, CEACAM-1, CD52, HER2, and any combination thereof.

76. The composition of claim 75, wherein the anti-PD-1 antibody comprises nivolumab or pembrolizumab.

77. 72. The composition of claim 71, wherein the additional anti-cancer therapy comprises CAR-T cell therapy.

78. 63. The composition of claim 62, wherein the antibody or antigen-binding fragment thereof, bispecific antibody, multispecific antibody, polynucleotide, vector, host cell, immunoconjugate, or pharmaceutical composition is administered intravenously, intraperitoneally, intramuscularly, intraarterially, intrathecally, intralymphatically, intralesional, intracapsular, intraorbital, intracardiac, intradermal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal, epidural, intrasternal, topically, epidermally, or mucosally.

79. The composition of claim 62, wherein the subject is a human.

80. A method for detecting a truncated human CDCP1 in a sample, comprising contacting the sample with an antibody or antigen-binding fragment thereof according to any one of claims 1, 2, 10-13, 24 and 25.

81. 81. The method of claim 80, wherein the sample is obtained from a human subject.

82. 81. The method of claim 80, wherein the sample is a cancer sample.

83. 81. The method of claim 80, wherein the sample is an in vitro sample.

84. 1. A method for identifying a cancer drug candidate, comprising generating an antibody or antigen-binding fragment thereof that specifically binds to truncated human complement C1r / C1s, Uegf, Bmp1 (CUB) domain-containing protein 1 (CDCP1), wherein the antibody or antigen-binding fragment thereof preferentially binds to truncated CDCP1.

85. The method of claim 84, wherein the antibody or antigen-binding fragment does not bind to full-length human CDCP1 at a detectable level.

86. The method of claim 84 or 85, wherein the binding between the antibody or antigen-binding fragment thereof and truncated or full-length CDCP1 is measured by biolayer interferometry analysis using an Octet instrument (ForteBio).

87. 86. The method of claim 84 or 85, wherein the truncated CDCP1 is generated by proteolytic cleavage from full-length human CDCP1 after residues K365, R368, and / or K369 corresponding to SEQ ID NO:

273.

88. 85. The method of claim 84, wherein the truncated CDCP1 comprises a membrane-associated complex.

89. 90. The method of claim 88, wherein the membrane-bound complex comprises a first cleavage domain associated with a second cleavage domain.

90. 90. The method of claim 89, wherein (i) the first cleavage domain consists of the amino acid sequence set forth in SEQ ID NO:63 and the second cleavage domain consists of the amino acid sequence set forth in SEQ ID NO:64; (ii) the first cleavage domain consists of the amino acid sequence set forth in SEQ ID NO:68 and the second cleavage domain consists of the amino acid sequence set forth in SEQ ID NO:70; or (iii) the first cleavage domain consists of the amino acid sequence set forth in SEQ ID NO:74 and the second cleavage domain consists of the amino acid sequence set forth in SEQ ID NO:

77.

91. The method of any one of claims 84, 85, 89, 90, wherein the truncated CDCP1 is produced by (a) culturing a host cell comprising a first polynucleotide encoding a first cleavage domain and a second polynucleotide encoding a second cleavage domain, and (b) isolating the truncated CDCP1.

92. An isolated antigen consisting of, or consisting essentially of, a truncated CDCP1 protein.

93. Truncated CDCP1 is (i) SEQ ID NOs: 63 and 64, respectively; (ii) SEQ ID NOs: 68 and 70, respectively; or (iii) SEQ ID NOs: 74 and 77, respectively.

93. The antigen of claim 92, which is a complex of an N-terminal fragment of CDCP1 and a C-terminal fragment of CDCP1, having the amino acid sequence set forth in:

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