Anti-FGFR3 antibodies and antigen-binding fragments and methods of use thereof

Abstract

The present invention provides antibodies that specifically bind to FGFR3, as well as methods for treating or preventing cancer, such as bladder cancer. Also provided herein are isolated antibodies or antigen-binding fragments thereof that specifically bind to FGFR3 or its antigen-binding fragments, which bind to the same FGFR3 epitope as the antibodies or antigen-binding fragments described herein or compete for binding to FGFR3. The present invention also provides complexes comprising such antibodies or antigen-binding fragments bound to FGFR3 or its antigen-binding fragments, which are also part of the present invention.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 383,686, filed November 14, 2022, and U.S. Provisional Application No. 63 / 587,538, filed October 3, 2023, the disclosures of both of which are incorporated herein by reference in their entireties.

[0002] Sequence Listing This application contains a Sequence Listing that has been submitted electronically in XML file format, which is incorporated herein by reference in its entirety. The XML copy, created on November 3, 2023, is named 250298_000563_SL.xml and is 265,438 bytes in size.

[0003] The present invention relates to antibodies and antigen-binding fragments thereof that specifically bind to FGFR3, and methods for treating conditions such as cancer. [Background technology]

[0004] Several cancer genome analysis studies have identified FGFR3 as a common mutation specific to non-inflammatory bladder tumors. FGFR3 mutations, including fusions, are commonly found in the luminal papillary (LumP) subclass of MIBC (30-40%), which is characterized by low immune cell infiltration.

[0005] CD73, or ecto-5'-nucleotidase (ecto5'-NT, EC3.1.3.5), is a cell surface enzyme that catalyzes the dephosphorylation of extracellular AMP to adenosine. It is widely expressed in many types of cancer and is associated with a prometastatic phenotype in melanoma and breast cancer. Adenosine activates immunoregulatory responses through specific receptors, protecting tissues from damage caused by excessive inflammation. Extracellular adenosine levels are kept low under physiological conditions but increase during inflammation and cell death. In T cells, the high-affinity adenosine receptor A2A (A2AR) is activated by adenosine to increase cytoplasmic cyclic AMP levels, which suppresses T cell functions such as proliferation and cytokine secretion. Erdafitinib is a pan-FGFR tyrosine kinase inhibitor (TKI) approved for the treatment of FGFR3-mutated bladder cancer. The rapid rise in resistance mutations and TKI-associated toxicities (hyperphosphatemia, ocular toxicity) present challenges in treating cancer by targeting FGFR3. Additionally, the antibody B-701 (vofatamab) is being investigated for use in the treatment of metastatic urothelial carcinoma (MUCC) and as targeted alpha-radiation therapy. Necchi et al., The Journal of Urology, Vol. 201, No. 4S Supplement, 2019, e840, abstract: PD47-08; Storozhuk et al., FGFR3 Targeted Alpha Therapeutic 225 AC]-FPI-1966 Induces Regression in Preclinical Bladder Xenograft Model (Fusion Pharmaceuticals, Inc. (2020)). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Necchi et al.,The Journal of Urology,Vol.201,No.4S Supplement,2019,e840,abstract:PD47-08 [Non-patent document 2] Storozhuk et al., FGFR3 Targeted Alpha Therapeutic[225AC]-FPI-1966 Induces Regression in Preclinical Bladder Xenograft Model (Fusion Pharmaceuticals, Inc. (2020)) Summary of the Invention [Means for solving the problem]

[0007] The present invention relates to an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 (e.g., monomeric or dimeric FGFR3b, optionally provided that the FGFR3 is not FGFR3c) or an antigen-binding fragment thereof, (optionally in combination with an FGFR inhibitor, such as, for example, erdafitinib, pemigatinib, infigratinib, rogaratinib, dexamethasone, alkylating agents, altretamine, trabectedin, or busulfan, nitrosoureas, carmustine, Lomustine, cytotoxic antibiotics, anthracyclines, doxorubicin, valrubicin, bleomycin, or dactinomycin, antimetabolites, methotrexate, floxuridine, clofarabine, pralatrexate, vinca alkaloids, vinblastine, vinorelbine, vincristine, vindesine, photodynamic drugs, porfimer sodium, aminolevulinic acid, platinum drugs, cisplatin, phenanthriplatin, taxanes, paclitaxel, docetaxel, topoisomerase inhibitors, thiazolinone ... HCDR1, HCDR2, and HCDR3 of an HCVR comprising the amino acid sequence set forth in SEQ ID NO: 2, 22, 42, 62, 82, 102, 122, 140, 159, 169, 179, 199, or 219 (together with additional therapeutic agents such as isomerase inhibitors, irinotecan, topotecan, etoposide, teniposide, ziv-aflibercept, anti-cancer antibodies, rituximab, trastuzumab, cetuximab, cemiplimab, pembrolizumab, panitumumab, and bevacizumab). and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of the LCVR comprising the amino acid sequence set forth in SEQ ID NO: 10, 30, 50, 70, 90, 110, 130, 148, 187, 207, or 227, or an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 as such an antibody or fragment or competes with such an antibody or fragment for binding to FGFR3. In one embodiment of the present invention, the antibody or antigen-binding fragment comprises: (a) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of the HCVR comprising the amino acid sequence set forth in SEQ ID NO: 2, and LCDR1, LCDR2, and LCDR3 of the LCVR comprising the amino acid sequence set forth in SEQ ID NO: 10,and LCDR3; (b) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 22, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 30; (c) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 42, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 50. (d) a light chain variable region (LCVR) comprising HCDR1, HCDR2, and HCDR3 of an HCVR comprising the amino acid sequence set forth in SEQ ID NO: 62, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of an LCVR comprising the amino acid sequence set forth in SEQ ID NO: 70; (e) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of an HCVR comprising the amino acid sequence set forth in SEQ ID NO: 82, and a light chain variable region (LCVR) comprising the amino acid sequence set forth in SEQ ID NO: 90. (f) a light chain variable region (LCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 102, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 110; (g) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 122, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 130. (h) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 140, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (i) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 159;and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of said LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (j) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of said HCVR comprising the amino acid sequence set forth in SEQ ID NO: 169, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of said LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (k) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of said HCVR comprising the amino acid sequence set forth in SEQ ID NO: 179, and LCDR1, LCDR2, and LCDR3 of said LCVR comprising the amino acid sequence set forth in SEQ ID NO: 187. (l) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of an HCVR comprising the amino acid sequence set forth in SEQ ID NO: 199, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of an LCVR comprising the amino acid sequence set forth in SEQ ID NO: 207, and / or (m) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of an HCVR comprising the amino acid sequence set forth in SEQ ID NO: 219, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of an LCVR comprising the amino acid sequence set forth in SEQ ID NO: 227. In one embodiment of the present invention, the antibody or antigen-binding fragment comprises: (a) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 4, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 6, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 8, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 12, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 16; (b) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 24, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 26, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 28, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 32, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 36;(c) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 44, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 46, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 48, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 52, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 54, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 56; (d) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 64, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 66, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 68, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 72, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 74, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 76; (e) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 84, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 86, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 88, and an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 92, (f) a light chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 104, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 106, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 108, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 112, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 114, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 116; (g) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 124, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 126, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 128, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 132, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 134; (h) an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 142, and an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 144;and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 153; (i) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 161, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 163, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 165, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 153; (j) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 171, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 173, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 175, and an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 153. a light chain variable region comprising a CDR3; (k) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 181, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 183, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 185, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 189, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 191, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 193; (l) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 201, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 203, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 205, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 209, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 211, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 213; and / or (m) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 221, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 223, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 225;and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 32, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 76. In one embodiment of the invention, the antibody or antigen-binding fragment thereof comprises a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 2, 22, 42, 62, 82, 102, 122, 140, 159, 169, 179, 199, or 219, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 10, 30, 50, 70, 90, 110, 130, 148, 187, 207, 218, 220, 222, 224, 226, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 240, 242 ... or a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 227. In one embodiment of the present invention, the antibody or antigen-binding fragment comprises: (a) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 2, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 10, (b) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 22, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 30, (c) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 42, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 50, (d) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 62, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 70, (e) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 82, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 90, (f) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 102, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 110, (g) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 122. and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 130; (h) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 140 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 148; (i) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 159 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 148; (j) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 169 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 148; (k) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 179 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 187; (l) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 199 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 207; and / or (m) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 219 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 227.In one embodiment of the invention, the antibody or antigen-binding fragment comprises (a) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 18, 38, 58, 78, 98, 118, 136, 155, 167, 177, 195, 215, or 229, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20, 40, 60, 80, 100, 120, 138, 157, 197, 217, 231, which can be, for example, (a) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 18, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20; (c) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 58 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 60; (d) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 78 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 80; (e) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 98 and the amino acid sequence set forth in SEQ ID NO: 100. (f) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 118 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 120; (g) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 136 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 138; (h) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 155 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 157; (i) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 167 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 157; (j) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 177 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 157; (k) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 195 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 197; (l) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 215 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 217; and / or (m) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 229 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 231.In one embodiment of the present invention, the antibody or antigen-binding fragment thereof is selected from the group consisting of: a. an epitope comprising the sequence GPTVWVK (SEQ ID NO: 260) and / or an epitope comprising the sequence TQR; b. an epitope comprising the sequence ADVR (SEQ ID NO: 258) and / or an epitope comprising the sequence IGVAEK (SEQ ID NO: 259); c. an epitope comprising the sequence HCKVY (SEQ ID NO: 261) and / or an epitope comprising the sequence KSWISE (SEQ ID NO: 262) and / or an epitope comprising the sequence ADVR (SEQ ID NO: 263); e. an epitope contained within or overlapping with the sequence GPTVWVK (SEQ ID NO: 260) and / or an epitope comprising the sequence T f. an epitope contained within or overlapping with QR, f. an epitope contained within or overlapping with sequence ADVR (SEQ ID NO: 258), and / or an epitope contained within or overlapping with sequence IGVAEK (SEQ ID NO: 259), and g. an epitope contained within or overlapping with HCKVY (SEQ ID NO: 261), and / or an epitope contained within or overlapping with sequence KSWISE (SEQ ID NO: 262), and / or an epitope contained within or overlapping with sequence ADVR (SEQ ID NO: 263). In one embodiment of the invention, the antibody or antigen-binding fragment thereof binds to one or more epitopes of FGFR3 selected from: a. an epitope consisting of the sequence GPTVWVK (SEQ ID NO: 260) and / or an epitope consisting of the sequence IGVAEK (SEQ ID NO: 259); b. an epitope consisting of the sequence ADVR (SEQ ID NO: 258) and / or an epitope consisting of the sequence IGVAEK (SEQ ID NO: 259); and c. an epitope consisting of the sequence HCKVY (SEQ ID NO: 261) and / or an epitope consisting of the sequence KSWISE (SEQ ID NO: 262) and / or an epitope consisting of the sequence ADVR (SEQ ID NO: 263).In one embodiment of the invention, the antibody or antigen-binding fragment thereof binds to one or more epitopes of FGFR3 selected from: a. an epitope comprising the sequence SCPPPGGGPMGPTVWVKDGTGLVPSER (SEQ ID NO: 245), and / or an epitope comprising the sequence YSCRQRLTQRVL (SEQ ID NO: 246); b. an epitope comprising the sequence LLAVPAAN (SEQ ID NO: 247), and / or an epitope comprising the sequence VLERSPHRPILQAG (SEQ ID NO: 248), and / or an epitope comprising the sequence YVTVLKSWISE (SEQ ID NO: 249).ADVRLR (SEQ ID NO: 250) and / or an epitope comprising the sequence LCRATNFIGVAEKAFW (SEQ ID NO: 251), c. an epitope comprising the sequence GQQEQLVFGSGDAVE (SEQ ID NO: 252), and / or an epitope comprising the sequence VLVGPQRL (SEQ ID NO: 253), d. an epitope comprising the sequence VLERSPHRPILQAG (SEQ ID NO: 254), and / or an epitope comprising the sequence HCKVYSDAQP (SEQ ID NO: 255), and / or the sequence YVTVLKSWISESVEADVRLR (SEQ ID NO: 256). and / or the sequence LCRATNFIGVAEKAF (SEQ ID NO: 257); e. an epitope contained within or overlapping with the sequence SCPPPGGGPMGPTVWVKDGTGLVPSER (SEQ ID NO: 245) and / or an epitope contained within or overlapping with the sequence YSCRQRLTQRVL (SEQ ID NO: 246); f. an epitope contained within or overlapping with the sequence LLAVPAAN (SEQ ID NO: 247) and / or an epitope contained within the sequence VLERSPHRPILQAG (SEQ ID NO: 248). an epitope contained within or overlapping with the sequence YVTVLKSWISE (SEQ ID NO: 249), or an epitope contained within or overlapping with the sequence ADVRLR (SEQ ID NO: 250), and / or an epitope contained within or overlapping with the sequence LCRATNFIGVAEKAFW (SEQ ID NO: 251); g. an epitope contained within or overlapping with the sequence GQQEQLVFGSGDAVE (SEQ ID NO: 252), and / or an epitope contained within or overlapping with the sequence VLVG PQRL (SEQ ID NO: 253), h. an epitope contained within or overlapping with the sequence VLERSPHRPILQAG (SEQ ID NO: 254), and / or an epitope contained within or overlapping with the sequence HCKVYSDAQP (SEQ ID NO: 255) and / or the sequence YVTVLKSWISESVEADVRLR (SEQ ID NO: 256), and / or an epitope contained within or overlapping with the sequence LCRATNFIGVAEKAF (SEQ ID NO: 257).In some embodiments, the antibody or antigen-binding fragment thereof is selected from the group consisting of: a. an epitope consisting of the sequence SCPPPGGGPMGPTVWVKDGTGLVPSER (SEQ ID NO: 245), and / or an epitope consisting of the sequence YSCRQRLTQRVL (SEQ ID NO: 246); b. an epitope consisting of the sequence LLAVPAAN (SEQ ID NO: 247), and / or an epitope consisting of the sequence VLERSPHRPILQAG (SEQ ID NO: 248), and / or an epitope consisting of the sequence YVTVLKSWISE (SEQ ID NO: 249), and / or an epitope consisting of the sequence ADVRLR (SEQ ID NO: 250), and / or an epitope consisting of the sequence LCRATNFIGVAEKAFW (SEQ ID NO: 251); c. an epitope consisting of the sequence GQQEQLVFGSGDAVE (SEQ ID NO: 252), and / or an epitope consisting of the sequence VLVGPQRL (SEQ ID NO: 253); and d. an epitope consisting of the sequence VLERSPHRPILQAG (SEQ ID NO: 254), and / or an epitope consisting of the sequence HCKVYSDAQP (SEQ ID NO: 255), and / or an epitope consisting of the sequence YVTVLKSWISESVEADVRLR (SEQ ID NO: 256), and / or an epitope consisting of the sequence LCRATNFIGVAEKAF (SEQ ID NO: 257).

[0008] Also provided herein are isolated antibodies or antigen-binding fragments thereof that specifically bind to FGFR3 or antigen-binding fragments thereof that bind to the same FGFR3 epitope as or compete for binding to FGFR3 as the antibodies or antigen-binding fragments described herein.

[0009] For example, the present invention provides antibodies or antigen-binding fragments thereof that specifically bind to FGFR3 or antigen-binding fragments thereof characterized by one or more of the following: an affinity (K) of about 16 nM or greater (e.g., about 16 nM, 12 nM, 10 nM, 7 nM, 5 nM, 4 nM, 3 nM, 2 nM, 1 nM, 0.5 nM, 0.22 nM, 0.2 nM, 0.19 nM, 0.14 nM, 0.1 nM) at 25°C (e.g., in a surface plasmon resonance assay). D) to monomeric human FGFR3b (e.g., C-terminally tagged with myc-myc-His6); and binds (e.g., in a surface plasmon resonance assay) at 25°C with an affinity (K ) of about 20 nM or greater (e.g., about 20 nM, 16 nM, 15 nM, 10 nM, 8 nM, 5 nM, 4 nM, 3 nM, 2 nM, 1 nM, 0.9 nM, 0.65 nM, 0.3 nM, 0.28 nM, 0.2 nM, 0.15 nM, 0.1 nM). D ) to monomeric cynomolgus monkey FGFR3b (e.g., C-terminally tagged with myc-myc-His6); and binds to monomeric cynomolgus monkey FGFR3b (e.g., C-terminally tagged with myc-myc-His6) with an affinity (K) of about 70 nM or greater (e.g., about 70 nM, 20 nM, 17 nM, 12 nM, 10 nM, 9 nM, 8 nM, 0.1 nM) at 25°C (e.g., in a surface plasmon resonance assay). D ) to monomeric mouse FGFR3b (e.g., C-terminally tagged with myc-myc-His6); does not significantly bind to monomeric human FGFR3c (e.g., C-terminally tagged with myc-myc-His6) at 25°C (e.g., in a surface plasmon resonance assay); has a higher affinity of about 0.6 nM (e.g., about 0.58 nM, 0.17 nM, 0.11 nM, 0.04 nM, 0.03 nM, 0.02 nM, 0.01 nM) at 25°C (e.g., in a surface plasmon resonance assay). The antibody binds to dimeric human FGFR3b (e.g., C-terminally tagged with mouse Fc (mFc)) with an affinity of 0.023 nM, 0.061 nM, 0.031 nM, 0.016 nM, 0.034 nM, or 0.027 nM; blocks the binding of acidic FGF1 to human FGFR3b-mFc by about 68% or more (3 g, 90%, or 0.5%) at 200 nM; and binds to monomeric cynomolgus monkey and monomeric mouse FGFR3b with an affinity of 0.023 nM, 0.061 nM, 0.031 nM, 0.016 nM, 0.034 nM, or 0.027 nM for monomeric or dimeric human FGFR3b. D K within approximately 0.1 nM D binds at IC concentrations of approximately 15 nM or less 50 (e.g., IC of about 1, 2, or 3 nM 50 ) blocks the binding of 4 nM human FGFR3b-mFc to human acidic FGF1 protein; competes with another anti-FGFR3 antibody described in Table 3-1 herein for binding to hFGFR3b.mmH; has an IC of about 18 nM or less50 (e.g., about 0.51 nM, 0.5 nM, 0.61 nM, 0.6 nM, or 0.012 nM) to block intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express wild-type or S249C mutant human fibroblast growth factor receptor 3b stimulated with human heparin (e.g., about 5 micrograms / ml) and human FGF1 ligand (e.g., about 1 nM); a lower IC than that for blocking intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express wild-type human fibroblast growth factor receptor 3b stimulated with human FGF1 ligand (e.g., about 1 nM) and human heparin (e.g., about 5 micrograms / ml). 50Blocks intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express S249C mutant human fibroblast growth factor receptor 3b stimulated with human heparin (e.g., at about 5 micrograms / ml) and human FGF1 ligand (e.g., at about 1 nM); blocks FGFR3 (e.g., wild-type or S249C mutant) dimerization with stronger inhibition than REGN6331, as measured by, for example, a non-reducing SDS-PAGE assay; ... reducing tumor size (e.g., bladder cancer tumors expressing FGFR3 (e.g., S249C mutant)) in a subject receiving the antibody or fragment; reducing CD73 expression (e.g., bladder cancer tumors expressing FGFR3 (e.g., S249C mutant)) in a subject receiving the antibody or fragment; inhibiting FGF1 / heparin-stimulated induced phosphorylation of MAPK in BaF3 cells expressing wild-type FGFR3 (e.g., S249C mutant); inhibiting endogenous FGFR3 (e.g., in a cancer cell spheroid proliferation assay) Inhibits the growth of UMUC14 bladder cancer cells expressing the S249C mutation; inhibits tumor growth of the bladder cancer cell line UMUC14 expressing FGFR3 (e.g., S249C mutation) in a mouse (e.g., SCID mouse) xenograft model; inhibits CD73-dependent adenosine-mediated inhibition of immune cell activation; inhibits CD8 / CD4 and / or CD8+ / T in tumor tissues with tumor cells expressing FGFR3 (e.g., S249C mutant). reg inhibit FGF3-mediated activation of CD73 expression and / or enzymatic activity (e.g., adenosine production) (e.g., in tumor cells expressing FGFR3 (e.g., S249C mutant)); inhibit FGFR3-dependent adenosine-mediated immune cell suppression; inhibit proliferation of BaF3 cells expressing FGFR3 double mutants (S249C and V557M or S249C and V557L) (wherein the antibody or antigen-binding fragment comprises an immunoglobulin chain comprising any of the amino acid sequences described herein).

[0010] The present invention also provides a complex comprising such an antibody or antigen-binding fragment thereof bound to FGFR3 or an antigen-binding fragment thereof, which is also part of the present invention.

[0011] Also within the scope of the present invention is a pharmaceutical formulation comprising an anti-FGFR3 antibody or fragment described herein and a pharmaceutically acceptable carrier.

[0012] The present invention further relates to the use of SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180 40, 142, 144, 146, 148, 150, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189, 191, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, 221, 223, 225, 227, 229, and 231, and any one of said polypeptides. Isolated polynucleotides encoding the above (e.g., SEQ ID NOs: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 130, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 2 31, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, 192, 194, 196, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, and 230. The present invention also includes vectors comprising the polynucleotides described herein.The present invention also provides host cells (eg, eukaryotic cells such as CHO cells or mammalian cells) comprising the polynucleotides described herein.

[0013] The present invention also provides a method for producing an anti-FGFR3 antibody or fragment described herein, comprising introducing a polynucleotide encoding a chain of the antibody or fragment into a host cell (e.g., a CHO cell), incubating the host cell containing the polynucleotide in a culture medium under conditions favorable for expression of the chain, and optionally isolating the antibody or fragment from the host cell and / or the culture medium.

[0014] The present invention further provides a method for administering an anti-FGFR3 antibody or fragment described herein to a subject, the method comprising introducing the antibody or fragment into the subject's body (e.g., by intramuscular, intravenous, or subcutaneous injection).

[0015] The present invention also provides a method of treating or preventing an FGFR3-mediated condition in a subject in need thereof, e.g., cancer (e.g., cancer mediated by cancer cells expressing the FGFR3 S249C mutation), bladder cancer, brain cancer, breast cancer, cervical cancer, colorectal cancer, endometrial cancer, gastric cancer, head and neck cancer, kidney cancer, lung cancer, multiple myeloma, ovarian cancer, pancreatic cancer, urothelial cancer, achondroplasia, Crouzon syndrome with acanthosis nigricans, epidermal nevus, hypochondroplasia, lacrimal-ear-tooth-digital (LADD) syndrome, Muenke syndrome, severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN), and / or thanatophoric dysplasia, comprising administering a therapeutically effective amount of an anti-FGFR3 antibody or fragment to the subject.

[0016] The present invention provides methods for reducing metastasis (e.g., CD73-dependent or adenosine-dependent) of tumor cells expressing FGFR3 (e.g., S249C mutant) in a subject in need thereof (e.g., a subject with cancer such as bladder cancer), reducing the concentration of adenosine in tumors expressing FGFR3 (e.g., S249C mutant), reducing CD73-dependent catalysis of AMP to adenosine by tumors expressing FGFR3 (e.g., S249C mutant), and / or inhibiting adenosine-mediated suppression of T cell function in tumors expressing FGFR3 (e.g., S249C mutant), comprising administering a therapeutically effective amount of an anti-FGFR3 antibody or fragment to the subject. [Brief explanation of the drawings]

[0017] [Figure 1] BaF3 / FGFR3 WT (top, left, and right panels) and BaF3 / FGFR3_S249C (bottom, left, and right panels) cells were treated with titrations of H4H30063P (left, top, and bottom panels) or H4H30102P2 (right, top, and bottom panels), along with a comparator antibody (REGN6331) and isotype-matched negative controls (REGN1945, REGN1932), in the presence of 1 nM FGF1 and 5 μg / ml heparin. Cell proliferation was determined using CellTiter-Glo, which measures ATP levels. [Figure 2] Non-reducing and reducing SDS-PAGE analysis of FGFR3 dimerization in the presence of various concentrations of H4H30063P or COMP6331 (REGN6331). The mobility of FGFR3 dimers and monomers is shown. [Figure 3] Western blot analysis of phosphorylated MAPK from in vitro BaF3 / hFGFR3b WT (wild type) in the presence of no antibody (-), 100 nM control antibody (Con Ig; REGN6331), or 100 nM H4H30063P, either with or without FGF1 and heparin stimulation. [Figure 4]Proliferation of UMUC14 bladder cancer cells treated with various concentrations (Log10 scale) of control antibody (IgG control), H4H30063P, H4H30071P, or REGN6331 relative to untreated cells. [Figure 5] UMUC14 tumor size (mm3) in xenografted SCID mice treated with control antibody (10 mg / kg), H4H30063P (3 mg / kg or 10 mg / kg), or REGN6331 (3 mg / kg or 10 mg / kg) over time. [Figure 6] Western blot analysis of CD73 protein expression in UMUC14 cells in vitro treated with control antibody (Con) or H4H30063P (FGFR3 Ab) or AZD4547 (FGFR TKI) at concentrations of 1 nM, 10 nM, and 100 nM. [Figure 7] Western blot analysis of CD73 protein expression in UMUC14 cells in vivo from xenografted mice treated with control antibody (Con) or H4H30063P (FGFR3 Ab). [Figure 8] Quantification of CD73 / actin Western blot band intensity from the blots in Figure 7 . [Figure 9] Western blot analysis of CD73 protein expression in cell lines expressing empty vector (EV), wild-type FGFR3 (FGFR3), FGFR3-TACC3 mutant, FGFR3 S249C mutant, or FGFR3 Y375C mutant. [Figure 10] A–C, Western blot analysis of CD73 protein expression in tumor cells from xenografted SCID mice expressing (A) empty vector (EV) or (B) the FGFR3 S249C mutant or (C) the FGFR3-TACC3 mutant. [Figure 11] A–B show Western blot analysis of the expression of CD73 protein levels in Fadu S249C tumor cells in xenografted mice treated with control antibody, H4H30063P antibody, or AZD4547 (B), and graphical quantification of band intensity (C). [Figure 12A]FGFR3 antibodies inhibit the growth of BaF3 cells expressing the TKI-resistant mutation V557L / M. [Figure 12B] FGFR3 antibodies inhibit the growth of BaF3 cells expressing the TKI-resistant mutation V557L / M. [Figure 13] HDX epitope mapping results for anti-FGFR3b H4H30117P2 and H4H30063P. [Figure 14] HDX epitope mapping results for anti-FGFR3b H4H30045P and H4H30108P2. [Figure 15] HDX protection with FGFR3 antibodies. Regions with greater than 20% and 25% HDX protection. [Figure 16A] HDX epitope mapping results for FGFR3 antibodies. [Figure 16B] HDX epitope mapping results for FGFR3 antibodies. [Figure 17] HDX epitope mapping results for H4H30063P. The figure discloses SEQ ID NO: 238. [Figure 18] HDX epitope mapping results for H4H30108P2. The figure discloses SEQ ID NO: 238. [Figure 19] HDX epitope mapping results for H4H30117P2. The figure discloses SEQ ID NO: 238. [Figure 20] HDX epitope mapping results for H4H30045P. The figure discloses SEQ ID NO: 238. [Figure 21] Illustrative hydrogen-deuterium exchange mass spectrometry experimental process. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention provides anti-FGFR3 antibodies that exhibit superior properties in vitro and in vivo. In some embodiments, the antibodies of the present invention exhibit greater binding to human monomeric FGFR3b, but not to FGFR3c. This property facilitates a more targeted approach to cancer treatment (i.e., the ability to inhibit the b-isoform but not the c-isoform). In contrast, Bioclin Therapeutics' anti-FGFR3 antibody, B-701, was observed to exhibit binding to FGFR3c. The anti-FGFR3 antibodies herein also exhibited superior biological activity to B-701, including, for example, greater inhibition of FGFR3b dimerization in mouse xenograft models, and in vitro cancer cell proliferation and tumor growth.

[0019] FGFR3 The term "FGFR3" refers to monomeric or dimeric human FGFR3b, to which the antibodies and antigen-binding fragments of the present invention specifically bind.

[0020] Fibroblast growth factor receptor 3 (FGFR3) belongs to a family of structurally related tyrosine kinase receptors that includes four distinct genes (FGFR1-4). These receptors have three glycosylated extracellular immunoglobulin-like (Ig-like) domains, a transmembrane domain, and an intracellular split tyrosine kinase domain. Ligand binding induces FGFR dimerization, leading to autophosphorylation of the kinase domain and interaction with and phosphorylation of effector signaling proteins. Alternative mRNA splicing mechanisms generate many different receptor isoforms with different ligand specificities. The isoforms FGFR3b and FGFR3c arise from mutually exclusive splicing events, and the second half of the third Ig-like domain is encoded by either the 151 nucleotides in exon 8 or the 145 nucleotides in exon 9. These two isoforms have different tissue distributions: for example, FGFR3b is the predominant form in epithelial cells, whereas FGFR3c is the predominant form in chondrocytes.

[0021] Mutations in FGFR3 are associated with autosomal dominant dwarfism and craniosynostosis syndromes, such as severe achondroplasia with hypochondroplasia, achondroplasia, developmental delay, and acanthosis nigricans (SADDAN), thanatophoric dysplasia, acanthosis nigricans, and Crouzon syndrome with Muenke coronal craniosynostosis. Reports demonstrate that these mutations result in constitutive activation of the receptor.

[0022] Additionally, FGFR3 plays an oncogenic role in human cancers. Indeed, somatic activating mutations in FGFR3 have been reported in multiple myeloma and, more recently, in two epithelial malignancies (i.e., bladder cancer and cervical cancer). FGFR3 is a driver of muscle-invasive bladder cancer (MIBC). Cappellen et al., Frequent activating mutations of FGFR3 in human bladder and cervix carcinomas Nat Genet 1999 23:18-20, Chesi et al., Frequent translocation t(4;14)(p16.3;q32.3)in multiple myeloma is associated with increased expression and activating mutations of fibroblast growth factor receptor 3 Nat Genet 1997 16:260-264, and Richelda et al. FGFR3 mutations are rare in multiple myeloma and cervical cancer, but are common in bladder cancer (74% of non-invasive papillary tumors), suggesting that constitutive activation of FGFR3 is a critical event in bladder tumorigenesis.Fracchiolla et al., FGFR3 gene mutations associated with human skeletal disorders occur rarely in multiple myeloma Blood 1998 92:2987-2989, Wu et al., Somatic mutations of fibroblast growth factor receptor 3(FGFR3) are uncommon in carcinomas of the uterine cervix Oncogene 2000 19:5543-5546, Billerey et al. See al. Frequent FGFR3 mutations in papillary non-invasive bladder (pTa) tumors Am J Pathol 2001 158:1955-1959, and Van Rhijn et al., The fibroblast growth factor receptor 3 (FGFR3) mutation is a strong indicator of superficial bladder cancer with low recurrence rate Cancer Res 2001 61:1265-1268. Many of the mutations identified in bladder tumors are identical to activating mutations that cause thanatophoric skeletal dysplasia, a lethal form of dwarfism.Cappellen et al., Frequent activating mutations of FGFR3 in human bladder and cervix carcinomas Nat Genet 1999 23:18-20, Billerey et al., Frequent FGFR3 mutations in papillary non-invasive bladder(pTa) tumors Am J Pathol 2001 158:1955-1959, Van Rhijn et al., The fibroblast growth factor receptor 3(FGFR3)mutation is a strong indicator of superficial bladder cancer with low recurrence rate Cancer Res 2001 61:1265-1268, and Sibley et al., Loss of heterozygosity at 4p16.3 and mutation of FGFR3 in transitional cell carcinoma Oncogene 2001 20:686-691. Of the 117 FGFR3 mutations identified by these groups, two (A393E and K652Q mutations) do not correspond to mutations in thanatophoric dysplasia: the A393E mutation is identical to a mutation associated with craniosynostosis syndrome (Crouzon syndrome with acanthosis nigricans), and the K652Q mutation is identical to a mutation associated with hypochondroplasia.

[0023] In one embodiment of the invention, the human FGFR3c isoform comprises the following amino acid sequence: [ka] (SEQ ID NO: 232)

[0024] In one embodiment of the present invention, the human FGFR3b isoform comprises the following amino acid sequence: [ka] (SEQ ID NO: 233)

[0025] In one embodiment of the present invention, the FGFR3 referred to herein comprises one or more of the following mutations: S249C, R248C, G372C, Y375C, K650E, or FGFR3-TACC3. See, e.g., Singh et al., Transforming fusions of FGFR and TACC genes in human glioblastoma. Science (New York, NY) 2012;337:1231-1235; Tomlinson et al., Knockdown by shRNA identifies S249C mutant FGFR3 as a potential therapeutic target in bladder cancer, Oncogene 2007 Aug 30 26(40):5889-99; Otsuka et al., Constitutively Active FGFR3 with Lys650Glu Mutation Enhances Bortezomib Sensitivity in Plasma Cell Malignancy, Anticancer Research January 2011,31(1)113-122.

[0026] antigen-binding proteins The present invention provides antigen-binding proteins, such as antibodies (e.g., human antibodies, monoclonal antibodies, and recombinant antibodies) and antigen-binding fragments thereof, that specifically bind to FGFR3 protein (e.g., monomeric or dimeric FGFR3b) or antigenic fragments thereof (e.g., the extracellular domain of FGFR3). In one embodiment of the present invention, the FGFR3 is an activating mutant (e.g., as discussed herein). Antigen binding proteins that bind to the same epitope on FGFR3 as, or compete for binding to, FGFR3 as, any of the antigen binding proteins described herein (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) are also part of the present invention.

[0027] As used herein, the term "antibody" refers to an immunoglobulin molecule (e.g., IgG) comprising four polypeptide chains, two heavy chains (HC) and two light chains (LC), interconnected by disulfide bonds. In one embodiment of the present invention, each antibody heavy chain (HC) comprises a heavy chain variable region ("HCVR" or "V"). H ") (e.g., SEQ ID NO: 2 or a variant thereof) and a heavy chain constant region, and each antibody light chain (LC) comprises a light chain variable region ("LCVR" or "V L ") (e.g., SEQ ID NO: 10 or a variant thereof) and a light chain constant region (CL). H and V L The regions can be further subdivided into regions of hypervariability, called complementarity determining regions (CDRs), interspersed with regions that are more conserved, called framework regions (FRs).

[0028] In one embodiment of the invention, the anti-FGFR3 antigen binding protein, e.g., antibody or antigen-binding fragment, comprises a heavy chain constant domain, e.g., of the IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., IgG1, IgG2, IgG3, and IgG4 (e.g., comprising an S228P and / or S108P mutation)), or IgM type. In some embodiments, the antigen binding protein, e.g., antibody or antigen-binding fragment, comprises a light chain constant domain, e.g., of the kappa or lambda type. In one embodiment of the invention, the VFGFR3 antigen binding protein described herein is H is linked to a human heavy chain constant domain (e.g., IgG) and is a V L is linked to a human light chain constant domain (e.g., kappa). The present invention includes antigen binding proteins comprising a variable domain described herein (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), which is linked to a heavy chain constant domain and / or a light chain constant domain described herein.

[0029] In one embodiment of the present invention, the amino acid assignments for each framework or CDR domain are determined according to the Sequences of Proteins of Immunological Interest, Kabat et al.; National Institutes of Health, Bethesda, Md.; th ed.; NIH Publ. No. 91-3242 (1991), Kabat (1978) Adv. Prot. Chem. 32:1-75, Kabat et al., (1977) J. Biol. Chem. 252:6609-6616; Chothia et al., (1987) J. Mol. Biol. 196:901-917 or Chothia et al., (1989) Nature 342:878-883. Therefore, the present invention is based on the definition of V H CDR and VL and antibodies and antigen-binding fragments comprising the CDRs of V H and V L comprises an amino acid sequence as described herein (or a variant thereof), and the CDRs are as defined according to Kabat and / or Chothia.

[0030] The FGFR3-binding protein described herein may be an antigen-binding fragment of an antibody. The term "antigen-binding portion" or "antigen-binding fragment" of an antibody, as used herein, refers to an immunoglobulin molecule that binds to an antigen but does not contain the entire sequence of a complete antibody (preferably, the complete antibody is an IgG). Non-limiting examples of antigen-binding fragments include (i) Fab fragments, (ii) F(ab')2 fragments, (iii) Fd fragments, (iv) Fv fragments, (v) single-chain Fv (scFv) molecules, and (vi) dAb fragments, which consist of amino acid residues that mimic the hypervariable regions of an antibody (e.g., isolated complementarity-determining regions (CDRs), such as CDR3 peptides) or constrained FR3-CDR3-FR4 peptides. Other engineered molecules, such as domain-specific antibodies, single-domain antibodies, one-arm antibodies, domain-deleted antibodies, chimeric antibodies, CDR-grafted antibodies, diabodies, triabodies, tetrabodies, minibodies, and small modular immunopharmaceuticals (SMIPs), are also encompassed by the term "antigen-binding fragment" as used herein.

[0031] "Isolated" antigen binding proteins (e.g., antibodies or antigen-binding fragments thereof), polypeptides, polynucleotides, and vectors are at least partially free from other biological molecules from the cell or cell culture in which they are produced. Such biological molecules include nucleic acids, proteins, other antibodies or antigen-binding fragments, lipids, carbohydrates, or other materials such as cell debris and growth medium. Isolated antigen binding proteins may also be at least partially free from expression system components such as biological molecules from the host cell or its growth medium. In general, the term "isolated" is not intended to refer to the complete absence of such biological molecules (e.g., trace or insignificant amounts of impurities may remain), or the absence of water, buffers or salts, or components of a pharmaceutical formulation that comprises the antigen binding protein (e.g., antibody or antigen-binding fragment).

[0032] The amino acid sequences of the polypeptides of the invention and the nucleotide sequences of the polynucleotides of the invention are shown in Tables A and B, respectively. [Table A] *In one embodiment of the invention, the heavy chain lacks a C-terminal lysine. [Table B] *In one embodiment of the invention, the heavy chain lacks a codon encoding a C-terminal lysine.

[0033] The sequences of the immunoglobulin chains of the anti-FGFR3 antibodies and antigen-binding fragments of the present invention are shown below. Thus, the present invention includes any antibody or antigen-binding fragment thereof comprising an HCVR and an LCVR having the amino acid sequences set forth below, or an HCVR and an LCVR having the HCDR and LCDR thereof, respectively. H4H30063P HCVR nucleotide sequence CAGGTGCAGCTGCAGGAGTCGGGCCCAGGACTGGTGAAGCCTTCGGAGACCCTGTCCCTCACCTGCACTGTCTCTGGTGACTCCATTAATAGTTACTTCTGGAGCTGGATCCGGCAGTTGCCAGGGAAGGAACTGGAGTGGATTGGCCATATCTATTCTAGTGGGAGTACCA GATACAACCCCTCCCTCCAGAGTCGAGTCACCATATCAATAGACACGTCCAAGAACCAGTTCTCCCTGAAGCTGAGTTCTGTGACCGCTGCGGACACGGCCGTATATTACTGTGCGAGGGGCGCCAGCGCAGTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 1) HCVR amino acid sequence [ka] (SEQ ID NO: 2) HCDR1 nucleotide sequence GGT GAC TCC ATT AAT AGT TAC TTC (SEQ ID NO: 3) HCDR1 amino acid sequence GDSINSYF (SEQ ID NO: 4) HCDR2 nucleotide sequence ATC TAT TCT AGT GGG AGT ACC (SEQ ID NO: 5) HCDR2 amino acid sequence IYSSGST (SEQ ID NO: 6) HCDR3 nucleotide sequence GCG AGG GGC GCC AGC GCA GTT GAC TAC (SEQ ID NO: 7) HCDR3 amino acid sequence ARGASAVDY (SEQ ID NO: 8) LCVR nucleotide sequence GAAATTGTGTTGACGCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGGGAAAGAGCCACCCTCTCCTGCAGGACCAGTCAGAGTATTAGCAGCGGCTATTTAGCCTGGTACCAGCAGAAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGTGCATCCAGA AGGGCCACTGGCATCCCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGACTGGAGCCTGAAGACTTTGTAGTGTATTACTGTCAACAATATGGTAGCTCACCATACACTTTTGGCCAGGGGACCAAGCTGGAGATCAAA (SEQ ID NO: 9) LCVR amino acid sequence [ka] (SEQ ID NO: 10) LCDR1 nucleotide sequence CAG AGT ATT AGC AGC GGC TAT (SEQ ID NO: 11) LCDR1 amino acid sequence QSISSGY (SEQ ID NO: 12) LCDR2 nucleotide sequence GGT GCA TCC (SEQ ID NO: 13) LCDR2 amino acid sequence GAS (SEQ ID NO: 14) LCDR3 nucleotide sequence CAA CAA TAT GGT AGC TCA CCA TAC ACT (SEQ ID NO: 15) LCDR3 amino acid sequence QQYGSSPYT (SEQ ID NO: 16) Heavy chain nucleotide sequence (SEQ ID NO: 17) Heavy chain amino acid sequence [ka] (SEQ ID NO: 18) Light chain nucleotide sequence GAAATTGTGTTGACGCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGGGAAAGAGCCACCCTCTCCTGCAGGACCAGTCAGAGTATTAGCAGCGGCTATTTAGCCTGGTACCAGCAGAAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGTGCATCCAGA AGGGCCACTGGCATCCCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGACTGGAGCCTGAAGACTTTGTAGTGTATTACTGTCAACAATATGGTAGCTCACCATACACTTTTGGCCAGGGGACCAAGCTGGAGATCAAA CGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 19) Light chain amino acid sequence [ka] (SEQ ID NO: 20) H4H30066P HCVR nucleotide sequence CAGGTGCAGCTGGTACAGTCTGGGGCTGAGGTGAAGAAGCCTGGGGCCTCAGTGAAGGTCTCCTGCAAGGTTTCCGGATACACCCTCACTGAATTATCCATGCACTGGGTGCGACAAGCTCCTGGAAAAGGGCTTGAGTGGATGGGAGGTTTTGATCCTGAAGATGGTGAAATAATCTACGCACAGAAG TTCCAGGGCAGAGTCACCATGACCGAGGACACATCTACAGACACAGCCTACATGGACCTGAGCAGTCTGACATCTGAAGACACGGCCGTGTATTACTGTGCAACGGAGAAGCAGCAACTGGTACGAAAATACTACTTCTACTACGGTTTGGCCGTCTGGGGCCAAGGGACCACGGTCACCGTCTCCTCA (SEQ ID NO: 21) HCVR amino acid sequence [ka] (SEQ ID NO: 22) HCDR1 nucleotide sequence GGA TAC ACC CTC ACT GAA TTA TCC (SEQ ID NO: 23) HCDR1 amino acid sequence GYTLTELS (SEQ ID NO: 24) HCDR2 nucleotide sequence TTT GAT CCT GAA GAT GGT GAA ATA (SEQ ID NO: 25) HCDR2 amino acid sequence FDPEDGEI (SEQ ID NO: 26) HCDR3 nucleotide sequence GCA ACG GAG AAG CAG CAA CTG GTA CGA AAA TAC TAC TTC TAC TAC GGT TTG GCC GTC (SEQ ID NO: 27) HCDR3 amino acid sequence ATEKQQLVRKYYFYYGLAV (SEQ ID NO: 28) LCVR nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGTTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGTCCCTAAGCTCCTGATCTATGCTGCATCCAGTT TGCAAAGTGGGGTCCCATCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTCCCCCATTCACTTTCGGCCCTGGGACCAAAGTGGATATCAAA (SEQ ID NO: 29) LCVR amino acid sequence [ka] (SEQ ID NO: 30) LCDR1 nucleotide sequence CAG AGC ATT AGC AGT TAT (SEQ ID NO: 31) LCDR1 amino acid sequence QSISSY (SEQ ID NO: 32) LCDR2 nucleotide sequence GCT GCA TCC (SEQ ID NO: 33) LCDR2 amino acid sequence AAS (SEQ ID NO: 34) LCDR3 nucleotide sequence CAA CAG AGT TAC AGT CCC CCA TTC ACT (SEQ ID NO: 35) LCDR3 amino acid sequence QQSYSPPFT (SEQ ID NO: 36) Heavy chain nucleotide sequence (SEQ ID NO: 37) Heavy Chain Amino Acids [ka] (SEQ ID NO: 38) Light chain nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGTTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGTCCCTAAGCTCCTGATCTATGCTGCATCCAGTTT GCAAAGTGGGGTCCCATCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTCCCCCATTCACTTTCGGCCCTGGGACCAAAGTGGATATCAAAC GAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 39) Light Chain Amino Acids [ka] (SEQ ID NO: 40) H4H30071P HCVR nucleotide sequence CAGGTACAGCTGCAGCAGTCAGGTCCAGGACTGGTGAAGCCCTCGCAGACCCTCTCACTCACCTGTGCCATCTCCGGGGACAGTGTCTCTAGGAACAGTGCTGCTTGGAACTGGATCAGGCAGTCCCCATCGAGTGGCCTTGAGTGGCTGGGAAGGACATACTACAGGTCCAAGTGGTTTTATG ATTATGCATATCTGTGAAAAGTCGAATAACCGTCAACCCAGACACATCCAAGAACCAATTCTCCCTTCACCTGAACTCTGTGACTCCCGAAGACACGGCTGTCTATTACTGTGCGAGAGGCTACGGTGGCTACGAGGACTACTTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 41) HCVR amino acid sequence [ka] (SEQ ID NO: 42) HCDR1 nucleotide sequence GGG GAC AGT GTC TCT AGG AAC AGT GCT GCT (SEQ ID NO: 43) HCDR1 amino acid sequence GDSVSRNSAA (SEQ ID NO: 44) HCDR2 nucleotide sequence ACA TAC TAC AGG TCC AAG TGG TTT TAT (SEQ ID NO: 45) HCDR2 amino acid sequence TYYRSKWFY (SEQ ID NO: 46) HCDR3 nucleotide sequence GCG AGA GGC TAC GGT GGC TAC GAG GAC TAC TTT GAC TAC (SEQ ID NO: 47) HCDR3 amino acid sequence ARGYGGYEDYFDY (SEQ ID NO: 48) LCVR nucleotide sequence GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGGTATTAGCAGCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGGTGCATCCAGTT TGCAAAGTGGGGTCCCATCAAGGTTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTTTTGTCAACAGGGTAGCAGTTTCCCGTACACTTTTGGCCAGGGGACCAAGCTGGAGATCAAA (SEQ ID NO: 49) LCVR amino acid sequence [ka] (SEQ ID NO: 50) LCDR1 nucleotide sequence CAG GGT ATT AGC AGC TGG (SEQ ID NO: 51) LCDR1 amino acid sequence QGISSW (SEQ ID NO: 52) LCDR2 nucleotide sequence GGT GCA TCC (SEQ ID NO: 53) LCDR2 amino acid sequence GAS (SEQ ID NO: 54) LCDR3 nucleotide sequence CAA CAG GGT AGC AGT TTC CCG TAC ACT (SEQ ID NO: 55) LCDR3 amino acid sequence QQGSSFPYT (SEQ ID NO: 56) Heavy chain nucleotide sequence (SEQ ID NO: 57) Heavy Chain Amino Acids [ka] (SEQ ID NO: 58) Light chain nucleotide sequence GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGGTATTAGCAGCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGGTGCATCCAGTTT GCAAAGTGGGGTCCCATCAAGGTTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTTTTGTCAACAGGGTAGCAGTTTCCCGTACACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC GAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 59) Light Chain Amino Acids [ka] (SEQ ID NO: 60) H4H30089P2 HCVR nucleotide sequence GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTACAGCCTGGAGGGTCCCTGAGACTCTCCTGTATAGTCTCTGGATTCATCTTCAGTAGTTATGAAATGAGCTGGCTCCGCCAGGCTCCAGGGAAGGGCCTGGAGTGGATTTCATATATTAGTAGTAGTGGTCGTGTCATATACT ATGCAGACTCTGTGAAGGGCCGATTCACCATCTCCAGAGACAGCGCCAAGAATTCACTGTATCTGGAAATGAATAGTCTGAGAGCCGAAGACACGGCTATATATTATTGTACGAGAAAGTGGGATAGTAGTGGCCCATTTGACTTCTGGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 61) HCVR amino acid sequence [ka] (SEQ ID NO: 62) HCDR1 nucleotide sequence GGA TTC ATC TTC AGT AGT TAT GAA (SEQ ID NO: 63) HCDR1 amino acid sequence GFIFSSYE (SEQ ID NO: 64) HCDR2 nucleotide sequence ATT AGT AGT AGT GGT CGT GTC ATA (SEQ ID NO: 65) HCDR2 amino acid sequence ISSSGRVI (SEQ ID NO: 66) HCDR3 nucleotide sequence ACG AGA AAG TGG GAT AGT AGT GGC CCA TTT GAC TTC (SEQ ID NO: 67) HCDR3 amino acid sequence TRKWDSSGPFDF (SEQ ID NO: 68) LCVR nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGCTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTG CAAAGTGGGGTCCCGTCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGGATCACCTTCGGCCAAGGGACACGACTGGAGATTAAA (SEQ ID NO: 69) LCVR amino acid sequence [ka] (SEQ ID NO: 70) LCDR1 nucleotide sequence CAG AGC ATT AGC AGC TAT (SEQ ID NO: 71) LCDR1 amino acid sequence QSISSY (SEQ ID NO: 72) LCDR2 nucleotide sequence GCT GCA TCC (SEQ ID NO: 73) LCDR2 amino acid sequence AAS (SEQ ID NO: 74) LCDR3 nucleotide sequence CAA CAG AGT TAC AGT ACC CCT CCG ATC ACC (SEQ ID NO: 75) LCDR3 amino acid sequence QQSYSTPPIT (SEQ ID NO: 76) Heavy chain nucleotide sequence (SEQ ID NO: 77) Heavy Chain Amino Acids [ka] (SEQ ID NO: 78) Light chain nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGCTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTG CAAAGTGGGGTCCCGTCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGGATCACCTTCGGCCAAGGGACACGACTGGAGATTAAA CGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 79) Light Chain Amino Acids [ka] (SEQ ID NO: 80) H4H30093P2 HCVR nucleotide sequence CAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTCAAGCCTGGAGGGTCCCTAAGACTCTCCTGTGCAGCCTCTGGATTCACCTTCAATGACTACCCAATGAGCTGGATCCGCCAGGCTCCAGGGAAGGGACTGGAGTGGGTTTCATACATTACTAGCAGTAGTGGTAGTACCATATACTACGCAG ACTCTGTGAAGGGCCGATTCACCATCTCCAGGGACAACGCCAAGAACTCACTGTATCTGCAAATGAACAGCCTGAGAGCCGAGGACACGGCCGTGTATTACTGTGCGAGAGGTTGTAGTGGCTACGATTGGGGCTACTACGGTATGGACGTCTGGGGCCAAGGGACCACGGTCACCGTCTCCTCA (SEQ ID NO: 81) HCVR amino acid sequence [ka] (SEQ ID NO: 82) HCDR1 nucleotide sequence GGA TTC ACC TTC AAT GAC TAC CCA (SEQ ID NO: 83) HCDR1 amino acid sequence GFTFNDYP (SEQ ID NO: 84) HCDR2 nucleotide sequence ATT ACT AGC AGT AGT GGT AGT ACC ATA (SEQ ID NO: 85) HCDR2 amino acid sequence ITSSSGSTI (SEQ ID NO: 86) HCDR3 nucleotide sequence GCG AGA GAG GTT GTA GTG GCT ACG ATT GGG GGC TAC TAC GGT ATG GAC GTC (SEQ ID NO: 87) HCDR3 amino acid sequence AREVVVATIGGYYGMDV (SEQ ID NO: 88) LCVR nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGCTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTG CAAAGTGGGGTCCCGTCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGGATCACCTTCGGCCAAGGGACACGACTGGAGATTAAA (SEQ ID NO: 89) LCVR amino acid sequence [ka] (SEQ ID NO: 90) LCDR1 nucleotide sequence CAG AGC ATT AGC AGC TAT (SEQ ID NO: 91) LCDR1 amino acid sequence QSISSY (SEQ ID NO: 92) LCDR2 nucleotide sequence GCT GCA TCC (SEQ ID NO: 93) LCDR2 amino acid sequence AAS (SEQ ID NO: 94) LCDR3 nucleotide sequence CAA CAG AGT TAC AGT ACC CCT CCG ATC ACC (SEQ ID NO: 95) LCDR3 amino acid sequence QQSYSTPPIT (SEQ ID NO: 96) Heavy chain nucleotide sequence (SEQ ID NO: 97) Heavy Chain Amino Acids [ka] (SEQ ID NO: 98) Light chain nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGCTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTG CAAAGTGGGGTCCCGTCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGGATCACCTTCGGCCAAGGGACACGACTGGAGATTAAA CGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 99) Light Chain Amino Acids [ka] (SEQ ID NO: 100) H4H30102P2 HCVR nucleotide sequence GAGGTGCAGCTGGTGGAGTCTGGGGGAGACTTGGTACAGCCTGGAGGGTCCCTGAGACTCTCCTGTGCAGCCTCTGGATTCACCTTCAGTAGTTATGAAATGAACTGGGTCCGCCAGGCTCCAGGGAAGGGGCTGGAGTGGGTTTCATACATTAGTAATAGTGGTTCTACCATATACTACGCAGACTCT GTGAAGGGCCGATTCACCATCTCCAGAGACAACGCCGAGACCTCACTGTATCTGCAAATGAACAGCCTGAGAGCCGAGGACACGGCTGTTTATTACTGTGCGAGAGAGGGATGGGCGCATATTGTGCTGGTGATTGCTATTCTGGTTTTGATATTTGGGGCCAAGGGACAATGGTCACCGTCTCTTCA (SEQ ID NO: 101) HCVR amino acid sequence [ka] (SEQ ID NO: 102) HCDR1 nucleotide sequence GGA TTC ACC TTC AGT AGT TAT GAA (SEQ ID NO: 103) HCDR1 amino acid sequence GFTFSSYE (SEQ ID NO: 104) HCDR2 nucleotide sequence ATT AGT AAT AGT GGT TCT ACC ATA (SEQ ID NO: 105) HCDR2 amino acid sequence ISNSGSTI (SEQ ID NO: 106) HCDR3 nucleotide sequence GCG AGA GAG GGA TGG GGC GCA TAT TGT GCT GGT GAT TGC TAT TCT GGT TTT GAT ATT (SEQ ID NO: 107) HCDR3 amino acid sequence AREGWGAYCAGDCYSGFDI (SEQ ID NO: 108) LCVR nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGCTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTG CAAAGTGGGGTCCCGTCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGGATCACCTTCGGCCAAGGGACACGACTGGAGATTAAA (SEQ ID NO: 109) LCVR amino acid sequence [ka] (SEQ ID NO: 110) LCDR1 nucleotide sequence CAG AGC ATT AGC AGC TAT (SEQ ID NO: 111) LCDR1 amino acid sequence QSISSY (SEQ ID NO: 112) LCDR2 nucleotide sequence GCT GCA TCC (SEQ ID NO: 113) LCDR2 amino acid sequence AAS (SEQ ID NO: 114) LCDR3 nucleotide sequence CAA CAG AGT TAC AGT ACC CCT CCG ATC ACC (SEQ ID NO: 115) LCDR3 amino acid sequence QQSYSTPPIT (SEQ ID NO: 116) Heavy chain nucleotide sequence (SEQ ID NO: 117) Heavy Chain Amino Acids [ka] (SEQ ID NO: 118) Light chain nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGCTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTG CAAAGTGGGGTCCCGTCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGGATCACCTTCGGCCAAGGGACACGACTGGAGATTAAA CGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 119) Light Chain Amino Acids [ka] (SEQ ID NO: 120) H4H30076P HCVR nucleotide sequence GAGGTGCAGCTGGTGGAGTCTGGAGGAGGCTTGGTCCAGCCTGGGGGGTCCCTGAGACTCTCCTGTGCAGCCTCTGGGTTCACCGTCAGTAGCAACTACATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGGCTGGAGTGGGTCTCAATTATTTATAGCGGTGGTCACACATACTACT CAGACTCCGTGAAGGCCGATTCACCATCTCCAGACACAATTCCAAGAACACTCTGTATCTTCAAATGAACAGCCTGAGAGGTGGGGACACGGCCGTGTATTACTGTGCGAGAGGGTATACCAGTGGCTGGTACGGATTTGACTTCTGGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 121) HCVR amino acid sequence [ka] (SEQ ID NO: 122) HCDR1 nucleotide sequence GGG TTC ACC GTC AGT AGC AAC TAC (SEQ ID NO: 123) HCDR1 amino acid sequence GFTVSSNY (SEQ ID NO: 124) HCDR2 nucleotide sequence ATT TAT AGC GGT GGT CAC ACA (SEQ ID NO: 125) HCDR2 amino acid sequence IYSGGHT (SEQ ID NO: 126) HCDR3 nucleotide sequence GCG AGA GGG TAT ACC AGT GGC TGG TAC GGA TTT GAC TTC (SEQ ID NO: 127) HCDR3 amino acid sequence ARGYTSGWYGFDF (SEQ ID NO: 128) LCVR nucleotide sequence GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGGTATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTT TGCAAAGTGGGGTCCCGTCAAGATTCAGCGGCACTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTATTATTGTCAGCAGACTAACAGTTTCCCGTGGACGTTCGGCCAAGGGACCAAGGTGGAAATCAAA (SEQ ID NO: 129) LCVR amino acid sequence [ka] (SEQ ID NO: 130) LCDR1 nucleotide sequence CAG GGT ATT AGC ACC TGG (SEQ ID NO: 131) LCDR1 amino acid sequence QGISTW (SEQ ID NO: 132) LCDR2 nucleotide sequence GCT GCA TCC (SEQ ID NO: 33) LCDR2 amino acid sequence AAS (SEQ ID NO: 34) LCDR3 nucleotide sequence CAG CAG ACT AAC AGT TTC CCG TGG ACG (SEQ ID NO: 133) LCDR3 amino acid sequence QQTNSFPWT (SEQ ID NO: 134) Heavy chain nucleotide sequence (SEQ ID NO: 135) Heavy chain amino acid sequence [ka] (SEQ ID NO: 136) Light chain nucleotide sequence GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGGTATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTT GCAAAGTGGGGTCCCGTCAAGATTCAGCGGCACTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTATTATTGTCAGCAGACTAACAGTTTCCCGTGGACGTTCGGCCAAGGGACCAAGGTGGAAATCAAAC GAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 137) Light chain amino acid sequence [ka] (SEQ ID NO: 138) H4H30105P2 HCVR nucleotide sequence GAGGTGCAGCTGGTGCAGTCTGGAGCAGAGGTGAAAAAGCCCGGGGAGTCTCTGAAGATCTCCTGTAAGGGTTCTGGATACAGCTTTACCAGCTACTGGATCGCCTGGGTGCGCCAGATGCCCGGGAAAGGCCTGGAGTGGATGGGGATCATCTATCCTGGTGACTCTGATACCAGAT ACAGCCCGTCCTTCCAAGGCCAGGTCACCATGTCAGCCGACAAGTCCATCAGGATCGCCTACCTGCAGTGGAGCAGCCTGAAGGCCTCGGACACCGCCATGTATTATTGTGCGAGACTTGATTATAGCGGCAGCTGGTTTGACTACTGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 139) HCVR amino acid sequence [ka] (SEQ ID NO: 140) HCDR1 nucleotide sequence GGA TAC AGC TTT ACC AGC TAC TGG (SEQ ID NO: 141) HCDR1 amino acid sequence GYSFTSYW (SEQ ID NO: 142) HCDR2 nucleotide sequence ATC TAT CCT GGT GAC TCT GAT ACC (SEQ ID NO: 143) HCDR2 amino acid sequence IYPGDSDT (SEQ ID NO: 144) HCDR3 nucleotide sequence GCG AGA CTT GAT TAT AGC GGC AGC TGG TTT GAC TAC (SEQ ID NO: 145) HCDR3 amino acid sequence ARLDYSGSWFDY (SEQ ID NO: 146) LCVR nucleotide sequence GAAATAGTTTTGACACAGAGTCCCGGCACACTGTCACTCTCTCCCGGGGAAAGAGCCACCTTGTCATGTAGAGCAAGTCAGTCAGTCTCTAGCTCTTATCTCGCCTGGTACCAGCAGAAGCCGGGACAGGCCCCTAGACTGCTGATCTACGGGGCAAGTTCC AGGGCCACCGGAATCCCCGACCGGTTCAGTGGAAGCGGAAGCGGAACCGATTTTACTTTGACGATTTCTAGACTGGAGCCAGAGGATTTCGCCGTTTACTATTGTCAACAGTACGGAAGCAGCCCGTGGACGTTTGGCCAGGGCACGAAGGTAGAAATCAAG (SEQ ID NO: 147) LCVR amino acid sequence [ka] (SEQ ID NO: 148) LCDR1 nucleotide sequence CAG TCA GTC TCT AGC TCT TAT (SEQ ID NO: 149) LCDR1 amino acid sequence QSVSSSY (SEQ ID NO: 150) LCDR2 nucleotide sequence GGG GCA AGT (SEQ ID NO: 151) LCDR2 amino acid sequence GAS (SEQ ID NO: 14) LCDR3 nucleotide sequence CAA CAG TAC GGA AGC AGC CCG TGG ACG (SEQ ID NO: 152) LCDR3 amino acid sequence QQYGSSPWT (SEQ ID NO: 153) Heavy chain nucleotide sequence (SEQ ID NO: 154) Heavy chain amino acid sequence [ka] (SEQ ID NO: 155) Light chain nucleotide sequence GAAATAGTTTTGACACAGAGTCCCGGCACACTGTCACTCTCTCCCGGGGAAAGAGCCACCTTGTCATGTAGAGCAAGTCAGTCAGTCTCTAGCTCTTATCTCGCCTGGTACCAGCAGAAGCCGGGACAGGCCCCTAGACTGCTGATCTACGGGGCAAGTTCC AGGGCCACCGGAATCCCCGACCGGTTCAGTGGAAGCGGAAGCGGAACCGATTTTACTTTGACGATTTCTAGACTGGAGCCAGAGGATTTCGCCGTTTACTATTGTCAACAGTACGGAAGCAGCCCGTGGACGTTTGGCCAGGGCACGAAGGTAGAAATCAAG CGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 156) Light chain amino acid sequence [ka] (SEQ ID NO: 157) H4H30108P2 HCVR nucleotide sequence CAGGTCCAGCTGGTGCAGTCTGGGCTGAGGTGAAGAAGCCTGGGGCCTCAGTGAAGGTCTCCTGCAAGGCTTCTGGATACACCTTCAACAGTTATGATGTCAACTGGGTGCGACAGGCCACTGGACAAGGGCTTGAGTGGATGGGATGGATGAACCCTCACAGTGGTAACACAGGCTACGCA CAGAAGTTCCAGGGCAGAGTCACTATGACCAGGGACACCTCCACAAGCACAAGCTATATGGAGTTGAGCAGCCTGACATCTGAGGACACGGCCGTATATTACTGTGCGAGAGGCCCTTTTTCTCTACTTTCAGCTGAATTCTTCCAGCACTGGGCCAGGGCACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 158) HCVR amino acid sequence [ka] (SEQ ID NO: 159) HCDR1 nucleotide sequence GGA TAC ACC TTC AAC AGT TAT GAT (SEQ ID NO: 160) HCDR1 amino acid sequence GYTFNSYD (SEQ ID NO: 161) HCDR2 nucleotide sequence ATG AAC CCT CAC AGT GGT AAC ACA (SEQ ID NO: 162) HCDR2 amino acid sequence MNPHSGNT (SEQ ID NO: 163) HCDR3 nucleotide sequence GCG AGA GGC CCT TTT TCT CTA CTT TCA GCT GAA TTC TTC CAG CAC (SEQ ID NO: 164) HCDR3 amino acid sequence ARGPFSLLSAEFFQH (SEQ ID NO: 165) LCVR nucleotide sequence GAAATAGTTTTGACACAGAGTCCCGGCACACTGTCACTCTCTCCCGGGGAAAGAGCCACCTTGTCATGTAGAGCAAGTCAGTCAGTCTCTAGCTCTTATCTCGCCTGGTACCAGCAGAAGCCGGGACAGGCCCCTAGACTGCTGATCTACGGGGCAAGTTCC AGGGCCACCGGAATCCCCGACCGGTTCAGTGGAAGCGGAAGCGGAACCGATTTTACTTTGACGATTTCTAGACTGGAGCCAGAGGATTTCGCCGTTTACTATTGTCAACAGTACGGAAGCAGCCCGTGGACGTTTGGCCAGGGCACGAAGGTAGAAATCAAG (SEQ ID NO: 147) LCVR amino acid sequence [ka] (SEQ ID NO: 148) LCDR1 nucleotide sequence CAG TCA GTC TCT AGC TCT TAT (SEQ ID NO: 149) LCDR1 amino acid sequence QSVSSSY (SEQ ID NO: 150) LCDR2 nucleotide sequence GGG GCA AGT (SEQ ID NO: 151) LCDR2 amino acid sequence GAS (SEQ ID NO: 14) LCDR3 nucleotide sequence CAA CAG TAC GGA AGC AGC CCG TGG ACG (SEQ ID NO: 152) LCDR3 amino acid sequence QQYGSSPWT (SEQ ID NO: 153) Heavy chain nucleotide sequence (SEQ ID NO: 166) Heavy chain amino acid sequence [ka] (SEQ ID NO: 167) Light chain nucleotide sequence GAAATAGTTTTGACACAGAGTCCCGGCACACTGTCACTCTCTCCCGGGGAAAGAGCCACCTTGTCATGTAGAGCAAGTCAGTCAGTCTCTAGCTCTTATCTCGCCTGGTACCAGCAGAAGCCGGGACAGGCCCCTAGACTGCTGATCTACGGGGCAAGTTCC AGGGCCACCGGAATCCCCGACCGGTTCAGTGGAAGCGGAAGCGGAACCGATTTTACTTTGACGATTTCTAGACTGGAGCCAGAGGATTTCGCCGTTTACTATTGTCAACAGTACGGAAGCAGCCCGTGGACGTTTGGCCAGGGCACGAAGGTAGAAATCAAG CGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 156) Light chain amino acid sequence [ka] (SEQ ID NO: 157) H4H30117P2 HCVR nucleotide sequence CAGGTCCAGCTGGTACAGTCTGGGGCTGAGGTGAAGAAGCCTGGGTCCTCGGTGAAGGTCTCCTGCAAGGCTTCTGGAGACACCTTCAGTAACTATGTTATCGGCTGGGTGCGACAGGCCCCTGGACAAGGGCTTGAGTGGATGGGAGGGATCATCCCTATCTTTGGTACAACAAACT ACGCACAGCAGTTCCAGGGCAGAGTCACGATTACCACGGACGAATCCACGAGCACGGCCTACATGGAGCTGAGCAGCCTGAGATCTGAGGACACGGCCGTGTATTACTGTGCGAGAGATGGGAACTACGGTGACTACTTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 168) HCVR amino acid sequence [ka] (SEQ ID NO: 169) HCDR1 nucleotide sequence GGA GAC ACC TTC AGT AAC TAT GTT (SEQ ID NO: 170) HCDR1 amino acid sequence GDTFSNYV (SEQ ID NO: 171) HCDR2 nucleotide sequence ATC ATC CCT ATC TTT GGT ACA ACA (SEQ ID NO: 172) HCDR2 amino acid sequence IIPIFGTT (SEQ ID NO: 173) HCDR3 nucleotide sequence GCG AGA GAT GGG AAC TAC GGT GAC TAC TTT GAC TAC (SEQ ID NO: 174) HCDR3 amino acid sequence ARDGNYGDYFDY (SEQ ID NO: 175) LCVR nucleotide sequence GAAATAGTTTTGACACAGAGTCCCGGCACACTGTCACTCTCTCCCGGGGAAAGAGCCACCTTGTCATGTAGAGCAAGTCAGTCAGTCTCTAGCTCTTATCTCGCCTGGTACCAGCAGAAGCCGGGACAGGCCCCTAGACTGCTGATCTACGGGGCAAGTTCC AGGGCCACCGGAATCCCCGACCGGTTCAGTGGAAGCGGAAGCGGAACCGATTTTACTTTGACGATTTCTAGACTGGAGCCAGAGGATTTCGCCGTTTACTATTGTCAACAGTACGGAAGCAGCCCGTGGACGTTTGGCCAGGGCACGAAGGTAGAAATCAAG (SEQ ID NO: 147) LCVR amino acid sequence [ka] (SEQ ID NO: 148) LCDR1 nucleotide sequence CAG TCA GTC TCT AGC TCT TAT (SEQ ID NO: 149) LCDR1 amino acid sequence QSVSSSY (SEQ ID NO: 150) LCDR2 nucleotide sequence GGG GCA AGT (SEQ ID NO: 151) LCDR2 amino acid sequence GAS (SEQ ID NO: 14) LCDR3 nucleotide sequence CAA CAG TAC GGA AGC AGC CCG TGG ACG (SEQ ID NO: 152) LCDR3 amino acid sequence QQYGSSPWT (SEQ ID NO: 153) Heavy chain nucleotide sequence (SEQ ID NO: 176) Heavy chain amino acid sequence [ka] (SEQ ID NO: 177) Light chain nucleotide sequence GAAATAGTTTTGACACAGAGTCCCGGCACACTGTCACTCTCTCCCGGGGAAAGAGCCACCTTGTCATGTAGAGCAAGTCAGTCAGTCTCTAGCTCTTATCTCGCCTGGTACCAGCAGAAGCCGGGACAGGCCCCTAGACTGCTGATCTACGGGGCAAGTTCC AGGGCCACCGGAATCCCCGACCGGTTCAGTGGAAGCGGAAGCGGAACCGATTTTACTTTGACGATTTCTAGACTGGAGCCAGAGGATTTCGCCGTTTACTATTGTCAACAGTACGGAAGCAGCCCGTGGACGTTTGGCCAGGGCACGAAGGTAGAAATCAAG CGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 156) Light chain amino acid sequence [ka] (SEQ ID NO: 157) H4H30045P HCVR nucleotide sequence CAGGTTCAGCTGGTGCAGTCTGGAGCTGAGGTGAAGAAGCCTGGGGCCTCAGTGAAGGTCTCCTGCAAGACTTCTGGTTACAGATTCGTCAACTATGGTTTCAGCTGGGTGCGCCAGGCCCCTGGACAAGGCCTTGAATGGATGGGATGGATCAGCCTTATAATGGTAACACAA ACTATATACAGAATCTCCAGGACAGAATCACCATGACCACAGACACCTCTACGAACACAGCCTACATGGAACTGACGAACCTGAGATCTGACGACACGGCCGTATATTACTGTGCGACCTTAACTGGGGTTCACTTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 178) HCVR amino acid sequence [ka] (SEQ ID NO: 179) HCDR1 nucleotide sequence GGT TAC AGA TTC GTC AAC TAT GGT (SEQ ID NO: 180) HCDR1 amino acid sequence GYRFVNYG (SEQ ID NO: 181) HCDR2 nucleotide sequence ATC AGC CCT TAT AAT GGT AAC ACA (SEQ ID NO: 182) HCDR2 amino acid sequence ISPYNGNT (SEQ ID NO: 183) HCDR3 nucleotide sequence GCG ACC TTA ACT GGG GTT CAC TTT GAC TAC (SEQ ID NO: 184) HCDR3 amino acid sequence ATLTGVHFDY (SEQ ID NO: 185) LCVR nucleotide sequence GCCATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGGGCATTAGAAATGATTTAGGCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAATCTCCTGATCTTTGAAACATCTCGTT TACAAAGTGGGGTCCCTTCGAGGTTCAGCGGCAGTGGTTCTGGCACAGATTTCACTCTCACCATCAACAGCCTTCAGCCTGAAGATTTTGCAACTTATTACTGTCTACAAGATTACAATTACCCGTGGACGTTCGGCCAAGGGACCAAGGTGGAAATCAAA (SEQ ID NO: 186) LCVR amino acid sequence [ka] (SEQ ID NO: 187) LCDR1 nucleotide sequence CAG GGC ATT AGA AAT GAT (SEQ ID NO: 188) LCDR1 amino acid sequence QGIRND (SEQ ID NO: 189) LCDR2 nucleotide sequence GAA ACA TCT (SEQ ID NO: 190) LCDR2 amino acid sequence ETS (SEQ ID NO: 191) LCDR3 nucleotide sequence CTA CAA GAT TAC AAT TAC CCG TGG ACG (SEQ ID NO: 192) LCDR3 amino acid sequence LQDYNYPWT (SEQ ID NO: 193) Heavy chain nucleotide sequence (SEQ ID NO: 194) Heavy chain amino acid sequence [ka] (SEQ ID NO: 195) Light chain nucleotide sequence GCCATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGGGCATTAGAAATGATTTAGGCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAATCTCCTGATCTTTGAAACATCTCGTTT ACAAAGTGGGGTCCCTTCGAGGTTCAGCGGCAGTGGTTCTGGCACAGATTTCACTCTCACCATCAACAGCCTTCAGCCTGAAGATTTTGCAACTTATTACTGTCTACAAGATTACAATTACCCGTGGACGTTCGGCCAAGGGACCAAGGTGGAAATCAAAC GAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 196) Light chain amino acid sequence [ka] (SEQ ID NO: 197) H4H30061P HCVR nucleotide sequence GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGCCCAGCCTGGGGGGTCCCTGAAACTCTCTTGTGAAGCCTCTGGATTCACGTTCAGTGATTCTGCAATGCACTGGGTCCGCCAGGCTTCCGGAAAAGGGCTGGAGTGGGTTGGTCGTATTAGAAGCAAAGCTAATAGTTACG CGACAGGATATGCTGCGTCGGTGAAAGGCAGGTTCACCATCTCCAGAGATGATTCAAAGAACATGGCGTTTCTGGAAATGAACAGCCTGAAACCGAAGACACGGCCGTATATTACTGTCTCCGACAAACTTACGGTGACCCCTGGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 198) HCVR amino acid sequence [ka] (SEQ ID NO: 199) HCDR1 nucleotide sequence GGA TTC ACG TTC AGT GAT TCT GCA (SEQ ID NO: 200) HCDR1 amino acid sequence GFTFSDSA (SEQ ID NO: 201) HCDR2 nucleotide sequence ATT AGA AGC AAA GCT AAT AGT TAC GCG ACA (SEQ ID NO: 202) HCDR2 amino acid sequence IRSKANSYAT (SEQ ID NO: 203) HCDR3 nucleotide sequence CTC CGA CAA ACT TAC GGT GAC CCC (SEQ ID NO: 204) HCDR3 amino acid sequence LRQTYGDP (SEQ ID NO: 205) LCVR nucleotide sequence GATGTTGTGATGACTCAGTCTCCACTCTCCCTGTCCGTCACCCTTGACAGCCGGCCTCCATCTCCTGCAGGTCTAGTCTAAGCCTCGTATACAGTGATGAAACAACTACTTGAATTGGTTTCAGCAGAGGCCAGGCCAATCTCCAAGGCGCCTACTTTATAAAGTT TTTAACCGGGACTCTGGGGTCCCAGACAGATTCAGCGGCAGTGGGTCAGGCACTGATTTCACACTGAAAATCAGCAGGGTGGAGGCTGAGGATGTTGGGGTTTATTACTGCATGCAAGGAACACACTGGCCGTGGACGTTCGGCCAAGGGACCAAGGTGGAAATCAAA (SEQ ID NO: 206) LCVR amino acid sequence [ka] (SEQ ID NO: 207) LCDR1 nucleotide sequence CTA AGC CTC GTA TAC AGT GAT GGA AAC AAC TAC (SEQ ID NO: 208) LCDR1 amino acid sequence LSLVYSDGNNY (SEQ ID NO: 209) LCDR2 nucleotide sequence AAA GTT TTT (SEQ ID NO: 210) LCDR2 amino acid sequence KVF (SEQ ID NO: 211) LCDR3 nucleotide sequence ATG CAA GGA ACA CAC TGG CCG TGG ACG (SEQ ID NO: 212) LCDR3 amino acid sequence MQGTHWPWT (SEQ ID NO: 213) Heavy chain nucleotide sequence (SEQ ID NO: 214) Heavy chain amino acid sequence [ka] (SEQ ID NO: 215) Light chain nucleotide sequence GATGTTGTGATGACTCAGTCTCCACTCTCCCTGTCCGTCACCCTTGACAGCCGGCCTCCATCTCCTGCAGGTCTAGTCTAAGCCTCGTATACAGTGATGGAAACAACTACTTGAATTGGTTTCAGCAGAGGCCAGGCCAATCTCCAAGGCGCCTACTTTATAAA GTTTTTAACCGGGACTCTGGGGTCCCAGACAGATTCAGCGGCAGTGGGTCAGGCACTGATTTCACACTGAAAATCAGCAGGGTGGAGGGCTGAGGATGTTGGGGTTTATTACTGCATGCAAGGAACACACTGGCCGTGGACGTTCGGCCAAGGGACCAAGGTGGAA ATCAAACGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAG GAGAGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 216) Light chain amino acid sequence [ka] (SEQ ID NO: 217) H4H30095P2 HCVR nucleotide sequence CAGGTTCAGCTGGTGCAGTCTGGAGTTTGAGGTGAAGAAGCCTGGGGCCTCAGTGAAGGTCTCCTGCAAGGCTTCTGGTTACACCTTTAAGTTTTATGGTATCAGTTGGGTGCGACAGGCCCCTGGACAAGGGCTTGAGTGGATGGGCTGGATCAGTGTTTACAATGGTAAAACAAAGTATGCA CAGAAGCTCCAGGGCAGAGTCACCATGACAACAGACACATCCACGAGCACAGCCTACATGGAGCTGAGGAGCCTGAGATCTGACGACACGGCCGTGTATTTTTGTGCGAGAGATGGGGACTATGAGAGTAGTGGTTATCCGTTTGACTACTGGGCCAGGGAACCCTGGTCACCGTCTCCTCA (SEQ ID NO: 218) HCVR amino acid sequence [ka] (SEQ ID NO: 219) HCDR1 nucleotide sequence GGT TAC ACC TTT AAG TTT TAT GGT (SEQ ID NO: 220) HCDR1 amino acid sequence GYTFKFYG (SEQ ID NO: 221) HCDR2 nucleotide sequence ATC AGT GTT TAC AAT GGT AAA ACA (SEQ ID NO: 222) HCDR2 amino acid sequence ISVYNGKT (SEQ ID NO: 223) HCDR3 nucleotide sequence GCG AGA GAT GGG GAC TAT GAG AGT AGT GGT TAT CCG TTT GAC TAC (SEQ ID NO: 224) HCDR3 amino acid sequence ARDGDYESSGYPFDY (SEQ ID NO: 225) LCVR nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGCTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTG CAAAGTGGGGTCCCGTCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGGATCACCTTCGGCCAAGGGACACGACTGGAGATTAAA (SEQ ID NO: 226) LCVR amino acid sequence [ka] (SEQ ID NO: 227) LCDR1 nucleotide sequence CAG AGC ATT AGC AGT TAT (SEQ ID NO: 31) LCDR1 amino acid sequence QSISSY (SEQ ID NO: 32) LCDR2 nucleotide sequence GCT GCA TCC (SEQ ID NO: 33) LCDR2 amino acid sequence AAS (SEQ ID NO: 34) LCDR3 nucleotide sequence CAA CAG AGT TAC AGT ACC CCT CCG ATC ACC (SEQ ID NO: 75) LCDR3 amino acid sequence QQSYSTPPIT (SEQ ID NO: 76) Heavy chain nucleotide sequence (SEQ ID NO: 228) Heavy chain amino acid sequence [ka] (SEQ ID NO: 229) Light chain nucleotide sequence GACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACCATCACTTGCCGGGCAAGTCAGAGCATTAGCAGCTATTTAAATTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTG CAAAGTGGGGTCCCGTCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGGATCACCTTCGGCCAAGGGACACGACTGGAGATTAAA CGAACTGTGGCTGCACCATCTGTCTTCATCTTCCCGCCATCTGATGAGCAGTTGAAATCTGGAACTGCCTCTGTTGTGTGCCTGCTGAATAACTTCTATCCCAGAGAGGCCAAAGTACAGTGGAAGGTGGATAACGCCCTCCAATCGGGTAACTCCCAGGAG AGTGTCACAGAGCAGGACAGCAAGGACAGCACCTACAGCCTCAGCAGCACCCTGACGCTGAGCAAAGCAGACTACGAGAAACACAAAGTCTACGCCTGCGAAGTCACCCATCAGGGCCTGAGCTCGCCCGTCACAAAGAGCTTCAACAGGGGAGAGTGTTAG (SEQ ID NO: 230) Light chain amino acid sequence [ka] (SEQ ID NO: 231)

[0034] The present invention provides an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 (e.g., monomeric or dimeric human FGFR3b) or an antigen-binding fragment thereof, comprising: a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of the HCVR comprising the amino acid sequence set forth in SEQ ID NO: 2, 22, 42, 62, 82, 102, 122, 140, 159, 169, 179, 199, or 219 (e.g., fused to IgG4 Fc having an S108P mutation); and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of the LCVR comprising the amino acid sequence set forth in SEQ ID NO: 10, 30, 50, 70, 90, 110, 130, 148, 187, 207, or 227.

[0035] The present invention also provides an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 (e.g., monomeric or dimeric human FGFR3b) or an antigen-binding fragment thereof, including: (a) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 2, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 10; (b) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 22, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 30; or (c) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 42. and a light chain variable region (LCVR) comprising an LCDR1, LCDR2, and LCDR3 of the LCVR comprising the amino acid sequence set forth in SEQ ID NO: 50; (d) a heavy chain variable region (HCVR) comprising an HCDR1, HCDR2, and HCDR3 of the HCVR comprising the amino acid sequence set forth in SEQ ID NO: 62, and a light chain variable region (LCVR) comprising an LCDR1, LCDR2, and LCDR3 of the LCVR comprising the amino acid sequence set forth in SEQ ID NO: 70; (e) a heavy chain variable region (HCVR) comprising an HCDR1, HCDR2, and HCDR3 of the HCVR comprising the amino acid sequence set forth in SEQ ID NO: 82, and a light chain variable region (LCVR) comprising an LCDR1, LCDR2, and LCDR3 of the LCVR comprising the amino acid sequence set forth in SEQ ID NO: 90; (f) a heavy chain variable region (HCVR) comprising an HCDR1, HCDR2, and HCDR3 of the HCVR comprising the amino acid sequence set forth in SEQ ID NO: 102 (e.g., an IgG4 having an S108P mutation). Fc), and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of the LCVR comprising the amino acid sequence set forth in SEQ ID NO: 110, and / or (g) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of the HCVR comprising the amino acid sequence set forth in SEQ ID NO: 122, and LCDR1, LCDR2 of the LCVR comprising the amino acid sequence set forth in SEQ ID NO: 130;and LCDR3; (h) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 140, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (i) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 159, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (j) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 169, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (k) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: Also provided is an isolated antibody or antigen-binding fragment thereof, comprising: (1) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 179, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 187; (2) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 199, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 207; and / or (3) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 219, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 227.

[0036] The present invention also provides an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 (e.g., monomeric or dimeric human FGFR3b) or an antigen-binding fragment thereof, comprising: (a) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 4, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 6, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 8, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 12, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 16; (b) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 24, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 26, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 28, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 32, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 36; (c) an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 44, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 46; and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 48, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 52, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 54, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 56; (d) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 64, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 66, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 68, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 72, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 74, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 76; (e) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 84, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 86, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 88, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 92, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 94, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 96;(f) a heavy chain variable region comprising HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 104, HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 106, and HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 108 (e.g., an IgG4 having an S108P mutation). Fc), and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 112, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 114, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 116; and / or (g) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 124, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 126, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 128, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 132, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 134; (h) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 142, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 144, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 146, and an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14 (i) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 161, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 163, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 165, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 153; (j) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 171, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 173, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 175, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 153; (k) an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 181;(l) a heavy chain variable region comprising an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 183 and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 185, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 189, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 191, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 193; (l) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 201, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 203, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 205, and an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 209, Also provided is an isolated antibody or antigen-binding fragment thereof, comprising: (m) a light chain variable region comprising an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 211, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 213; and / or (m) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 221, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 223, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 225, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 32, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 76.

[0037] The present invention further provides an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 2, 22, 42, 62, 82, 102, 122, 140, 159, 169, 179, 199, or 219 (e.g., fused to an IgG4 Fc having an S108P mutation), and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 10, 30, 50, 70, 90, 110, 130, 148, 187, 207, or 227.

[0038] Additionally, the present invention provides an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 (e.g., monomeric or dimeric human FGFR3b) or an antigenic fragment thereof, comprising: (a) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 2 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 10; (b) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 22 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 30; (c) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 42 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 50; (d) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 62 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 70; (e) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 82 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 90; (f) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 102 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 110 (e.g., the heavy chain variable region is an IgG4 antibody having an S108P mutation). (i) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 159 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 148; (j) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 169 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 148; (k) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 179 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 187; (l) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 199 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 207; and / or (m) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 219 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 227.

[0039] The present invention provides an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 (e.g., monomeric or dimeric human FGFR3b) or an antigen-binding fragment thereof, comprising: (a) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 18, 38, 58, 78, 98, 118, 136, 155, 167, 177, 195, 215, or 229, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20, 40, 60, 80, 100, 120, 138, 157, 197, 217, or 231.

[0040] The present invention also provides an isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, comprising: (a) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 18 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20; (b) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 38 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 40; (c) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 58 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 60; (d) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 78 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 80; (e) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 98 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 100; (f) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 118 and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 120; and / or (g) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 136. (i) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 167 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 157; (j) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 177 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 157; (k) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 195 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 197; (l) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 215 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 217; and / or (m) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 229 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 231.

[0041] In one embodiment of the present invention, the anti-FGFR3 antigen binding protein, such as an antibody or antigen-binding fragment thereof, has one or more of the following characteristics: an affinity (K) of about 16 nM or greater (e.g., about 16 nM, 12 nM, 10 nM, 7 nM, 5 nM, 4 nM, 3 nM, 2 nM, 1 nM, 0.5 nM, 0.22 nM, 0.2 nM, 0.19 nM, 0.14 nM, 0.1 nM) at 25°C (e.g., in a surface plasmon resonance assay);D ), which binds to monomeric human FGFR3b (e.g., C-terminally tagged with myc-myc-His6); an affinity (K ) of about 20 nM or greater (e.g., about 20 nM, 16 nM, 15 nM, 10 nM, 8 nM, 5 nM, 4 nM, 3 nM, 2 nM, 1 nM, 0.9 nM, 0.65 nM, 0.3 nM, 0.28 nM, 0.2 nM, 0.15 nM, 0.1 nM) at 25°C (e.g., in a surface plasmon resonance assay); D ), which binds to monomeric cynomolgus monkey FGFR3b (e.g., C-terminally tagged with myc-myc-His6); an affinity (K) of about 70 nM or greater (e.g., about 70 nM, 20 nM, 17 nM, 12 nM, 10 nM, 9 nM, 8 nM, 0.1 nM) at 25°C (e.g., in a surface plasmon resonance assay); D ), which binds to monomeric mouse FGFR3b (e.g., C-terminally tagged with myc-myc-His6); • does not significantly bind to monomeric human FGFR3c (e.g., C-terminally tagged with myc-myc-His6) at 25°C (e.g., in a surface plasmon resonance assay); • binds to dimeric human FGFR3b (e.g., C-terminally tagged with mouse Fc (mFc)) with a higher affinity of about 0.6 nM (e.g., about 0.58 nM, 0.17 nM, 0.11 nM, 0.04 nM, 0.03 nM, 0.02 nM, 0.01 nM, 0.023 nM, 0.061 nM, 0.031 nM, 0.016 nM, 0.034 nM, 0.027 nM) at 25°C (e.g., in a surface plasmon resonance assay); • Blocks the binding of acidic FGF1 to human FGFR3b-mFc by approximately 68% or more (e.g., 90% or 0.5%) at 200 nM antibody; K binds to monomeric or dimeric human FGFR3b D K within approximately 0.1 nM of D and binds to monomeric cynomolgus monkey and monomeric mouse FGFR3b; IC at a concentration of approximately 15 nM or less 50 (e.g., IC of about 1, 2, or 3 nM 50) to block the binding of 4 nM human FGFR3b-mFc to human acidic FGF1 protein; • competes for binding to hFGFR3b.mmH with another anti-FGFR3 antibody described in Table 3-1 herein; IC at a concentration of about 18 nM or less (e.g., about 0.51 nM, 0.5 nM, 0.61 nM, 0.6 nM, or 0.012 nM) 50 to block intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express wild-type or S249C mutant human fibroblast growth factor receptor 3b stimulated with human heparin (e.g., about 5 micrograms / ml) and human FGF1 ligand (e.g., about 1 nM); A lower IC than that of blocking intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express wild-type human fibroblast growth factor receptor 3b stimulated with human FGF1 ligand (e.g., at approximately 1 nM) and human heparin (e.g., at approximately 5 micrograms / ml) 50 to block intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express the S249C mutant human fibroblast growth factor receptor 3b stimulated with human heparin (e.g., about 5 micrograms / ml) and human FGF1 ligand (e.g., about 1 nM); • Blocks dimerization of FGFR3 (e.g., wild-type or S249C mutant) with stronger inhibition than, for example, REGN6331, as measured by a non-reducing SDS-PAGE assay; • reducing tumor size (e.g., bladder cancer tumors expressing FGFR3 (e.g., S249C mutant)) in a subject receiving the antibody or fragment; • reducing the expression of CD73 in tumors (e.g., bladder cancer tumors expressing FGFR3 (e.g., S249C mutant)) in subjects receiving the antibody or fragment; • For example, inhibiting FGF1 / heparin stimulation-induced phosphorylation of MAPK in BaF3 cells expressing wild-type FGFR3 (e.g., S249C mutant); • inhibiting the growth of UMUC14 bladder cancer cells expressing the endogenous FGFR3 S249C mutation (e.g., in cancer cell spheroid proliferation assays); • Inhibits tumor growth of the bladder cancer cell line UMUC14 expressing FGFR3 (e.g., S249C mutation) in a mouse (e.g., SCID mouse) xenograft model; • Inhibits CD73-dependent adenosine-mediated inhibition of immune cell activation; The CD8 / CD4 ratio and / or CD8+ / T in tumor tissues with tumor cells expressing FGFR3 (e.g., S249C mutant) reg Increase the ratio of; • inhibiting FGF3-mediated activation of CD73 expression and / or enzymatic activity (e.g., adenosine production) (e.g., on tumor cells expressing FGFR3 (e.g., S249C mutant)); • Inhibits FGFR3-dependent adenosine-mediated immune cell suppression; • Inhibits the proliferation of BaF3 cells expressing a FGFR3 double mutant (S249C and V557M or S249C and V557L) that contains an immunoglobulin chain comprising any of the amino acid sequences described herein.

[0042] The present invention includes monoclonal anti-FGFR3 antigen binding proteins, e.g., antibodies and antigen-binding fragments thereof (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), as well as monoclonal compositions comprising a plurality of isolated monoclonal antigen binding proteins. As used herein, the term "monoclonal antibody" or "mAb" refers to an antibody from a population of substantially homogeneous antibodies, i.e., the antibody molecules comprising the population are identical in amino acid sequence except for possible naturally occurring mutations that may be present in minor amounts. A "plurality" of such monoclonal antibodies and fragments in a composition refers to a concentration of identical (i.e., in amino acid sequence, excluding possible naturally occurring variations that may be present in small amounts, as discussed above) antibodies and fragments that exceeds the concentration normally present in nature, e.g., in the blood of a host organism such as a mouse or human.

[0043] In one embodiment of the present invention, the anti-FGFR3 antigen binding protein, e.g., antibody or antigen-binding fragment, comprises a heavy chain constant domain, e.g., of the IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., IgG1, IgG2, IgG3, and IgG4 (e.g., comprising an S228P and / or S108P mutation)), or IgM type. In some embodiments, the antigen binding protein, e.g., antibody or antigen-binding fragment, comprises a light chain constant domain, e.g., of the kappa or lambda type. The present invention relates to the VFGFR3 antigen binding proteins described herein. H and V Land antigen binding proteins comprising a variable domain (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), which are linked to a heavy chain constant domain and / or a light chain constant domain, e.g., as described herein.

[0044] The term "human" antigen-binding protein (e.g., antibody or antigen-binding fragment), as used herein, includes antibodies and fragments having human amino acid sequences (e.g., variable and constant regions derived from human germline immunoglobulin sequences), whether in a human cell or grafted into a non-human cell (e.g., a mouse cell). See, e.g., US8502018, US6596541, or US5789215. In embodiments of the invention, the human antibodies and antigen-binding fragments of the present invention may include amino acid residues in the CDRs, particularly CDR3, that are not encoded by human germline immunoglobulin sequences (e.g., with 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 mAbs in which CDR sequences derived from the germline of another mammalian species (e.g., a mouse) are grafted onto human FR sequences. This term includes antibodies recombinantly produced in a non-human mammal or in the cells of a non-human mammal. The term is not intended to include antibodies isolated from or produced in a human subject. The present invention includes human antigen-binding proteins (e.g., antibodies or antigen-binding fragments thereof such as H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2).

[0045] The present invention includes anti-FGFR3 chimeric antigen-binding proteins, such as antibodies and antigen-binding fragments thereof, and methods for using them. As used herein, a "chimeric antibody" is an antibody that has a variable domain from a first antibody and a constant domain from a second antibody, and the first antibody and the second antibody are derived from different species (see, for example, US4816567, and Morrison et al., (1984) Proc.Natl.Acad.Sci.USA 81:6851-6855). The present invention includes chimeric antibodies comprising a variable domain described herein (e.g., from H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) and a non-human constant domain.

[0046] The term "recombinant" antigen-binding protein, such as an antibody or antigen-binding fragment thereof, refers to such molecules that are produced, expressed, isolated, or obtained by techniques or methods known in the art, such as recombinant DNA technology, including, for example, DNA splicing and transgenic expression. The term includes antibodies expressed in a non-human mammal (including a transgenic non-human mammal, e.g., a transgenic mouse), or in a host cell (e.g., a Chinese hamster ovary (CHO) cell) or cellular expression system, or antibodies isolated from a recombinant combinatorial human antibody library. The present invention includes recombinant antigen-binding proteins such as the antibodies and antigen-binding fragments described herein (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2).

[0047] Antigen-binding fragments of antibodies, in one embodiment of the present invention, include antibodies that are less than a complete antibody, but still specifically bind to an antigen, e.g., FGFR3, and that include, for example, at least one variable domain. The variable domain may be of any size or amino acid composition and generally includes at least one (e.g., three) CDR(s) adjacent to or in-frame with one or more framework sequences. L V associated with the domain H For antigen-binding fragments containing domains, V H Domains and V L The domains can be positioned relative to each other in any suitable configuration. For example, the variable region can be a dimer, with the V H -V H , V H -V L or V L -V L Alternatively, the antigen-binding fragment of an antibody may be formed by non-covalently linking monomeric V dimers. H and / or V L It may contain domains.

[0048] In certain embodiments, an antigen-binding fragment of an antibody may comprise at least one variable domain covalently linked to at least one constant domain. Non-limiting exemplary configurations of variable and constant domains that may be found in an antigen-binding fragment of an antibody of the invention include: (i) a V H -CH1, (ii) V H -CH2, (iii) V H -CH3, (iv)V H -CH1-CH2, (v) V H -CH1-CH2-CH3, (vi) V H -CH2-CH3, (vii)V H -CL, (viii)V L -CH1, (ix)V L -CH2, (x)V L -CH3, (xi)V L -CH1-CH2, (xii)VL-CH1-CH2-CH3, (xiii)V L -CH2-CH3, and (xiv) VL -CL. In any arrangement of variable and constant domains, including any of the exemplary arrangements listed above, the variable and constant domains can be either directly linked to each other or linked by a complete or partial hinge or linker region. The hinge region can consist of at least two (e.g., 5, 10, 15, 20, 40, 60 or more) amino acids that provide a flexible or semi-flexible connection between adjacent variable and / or constant domains in a single polypeptide molecule. Furthermore, antigen-binding fragments of antibodies of the present invention can be linked to each other and / or to one or more monomeric V H Domain or V L The present invention may comprise homodimers or heterodimers (or other multimers) of any of the variable and constant domain arrangements listed above in non-covalent association with the domains (e.g., by disulfide bond(s)). The present invention includes antigen-binding fragments of antigen-binding proteins such as antibodies described herein (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2).

[0049] Antigen-binding proteins (e.g., antibodies and antigen-binding fragments) can be monospecific or multispecific (e.g., bispecific). Multispecific antigen-binding proteins are discussed further herein. The present invention includes monospecific as well as multispecific (e.g., bispecific) antigen-binding fragments comprising one or more variable domains from the antigen-binding proteins specifically described herein (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2).

[0050] In some embodiments, the antigen-binding fragments described herein can be scFvs. scFvs (single-chain fragment variable regions) are composed of heavy (V H ) domain and light (V L ) domain variable regions (in either order), which are preferably linked together by a flexible linker (e.g., a peptide linker). The length of the flexible linker used to link both V regions can be important for ensuring correct folding of the polypeptide chain. Previously, it has been estimated that a peptide linker must span 3.5 nm (35 Å) between the carboxy terminus of one variable domain and the amino terminus of the other domain without affecting the ability of the domains to fold to form an intact antigen-binding site (Huston et al., Protein engineering of single-chain Fv analogs and fusion proteins. Methods in Enzymology. 1991;203:46-88). In one embodiment, the linker comprises an amino acid sequence of such length that it separates the variable domains by approximately 3.5 nm. In one embodiment, the anti-FGFR3 scFv comprises a variable region arrangement such as LCVR-HCVR or HCVR-LCVR, where the HCVR and LCVR are optionally connected by a linker.

[0051] In some embodiments, the antigen-binding fragment described herein can be a Fab.

[0052] In some embodiments, the antigen-binding fragments described herein may be bivalent antibodies.

[0053] In some embodiments, the anti-FGFR3 antibodies described herein include monovalent or "one-arm" antibodies. As used herein, a monovalent or "one-arm" antibody refers to an immunoglobulin protein comprising a single variable domain. For example, a one-arm antibody may comprise a single variable domain within a Fab, which is linked to at least one Fc fragment. In certain embodiments, a one-arm antibody comprises a polypeptide comprising: (i) a heavy chain comprising a heavy chain constant region and a heavy chain variable region; (ii) a light chain comprising a light chain constant region and a light chain variable region; and (iii) an Fc fragment or a truncated heavy chain. In certain embodiments, the Fc fragment or truncated heavy chain contained in a separate polypeptide is a "dummy Fc," which refers to an Fc fragment not linked to an antigen-binding domain. The one-arm antibodies described herein may comprise any of the HCVR / LCVR pairs or CDR amino acid sequences listed in Table 1-1 herein. One-arm antibodies comprising a full-length heavy chain, a full-length light chain, and an additional Fc domain polypeptide can be constructed using standard methodology (see, e.g., WO2010 / 151792, incorporated herein by reference in its entirety), where the heavy chain constant region differs from the Fc domain polypeptide by at least two amino acids (e.g., H95R and Y96F according to the IMGT exon numbering system, H435R and Y436F according to the EU numbering system). Such modifications are useful for purifying monovalent antibodies (see, e.g., WO2010 / 151792).

[0054] The terms "specifically binds" or "binds specifically" refer to an affinity of at least about 10 as measured by a real-time label-free biolayer interferometry assay (e.g., Octet® HTX biosensor at 25°C or 37°C), by surface plasmon resonance (e.g., BIACORE™), or by solution affinity ELISA. -9M (e.g., 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 nM) to an antigen, e.g., human FGFR3 protein (e.g., FGFR3b isoform), mouse FGFR3 protein (e.g., FGFR3b isoform), or cynomolgus monkey FGFR3 protein (e.g., FGFR3b isoform). D The term "anti-FGFR3" refers to those antigen-binding proteins (e.g., antibodies or antigen-binding fragments thereof) that specifically bind to FGFR3 proteins (e.g., FGFR3b isoforms). The present invention includes antigen-binding proteins that specifically bind to FGFR3 proteins (e.g., FGFR3b isoforms). "Anti-FGFR3" refers to antigen-binding proteins (or other molecules), e.g., antibodies or antigen-binding fragments thereof, that specifically bind to FGFR3 (e.g., FGFR3b isoforms).

[0055] The present invention includes antigen binding proteins, e.g., antibodies or antigen-binding fragments that bind to the same epitope as an antigen binding protein of the invention (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2).

[0056] An antigen is a molecule, such as a peptide (e.g., FGFR3 or a fragment thereof (antigenic fragment)) to which an antibody or its antigen-binding fragment binds. The specific region on an antigen that an antibody recognizes and binds to is called an epitope. Antigen-binding proteins (e.g., antibodies) of the present invention that specifically bind to such antigens are part of the present invention.

[0057] The term "epitope" refers to an antigenic determinant (e.g., on FGFR3b) that interacts with a specific antigen-binding site of an antigen-binding protein, e.g., the variable region of an antibody known as the paratope. A single antigen may have multiple epitopes. Thus, different antibodies may bind to different regions on an antigen and have different biological effects. The term "epitope" may also refer to the site on an antigen to which B and / or T cells respond and / or the region of an antigen bound by an antibody. Epitopes may be defined as structural or functional. Functional epitopes are generally a subset of structural epitopes and contain residues that directly contribute to the affinity of the interaction. Epitopes may be linear or conformational, i.e., composed of non-linear amino acids. In certain embodiments, epitopes may include determinants that are chemically active surface groups of molecules, such as amino acids, sugar side chains, phosphoryl groups, or sulfonyl groups, and in certain embodiments, may have specific three-dimensional structural characteristics and / or specific charge characteristics. The epitope to which the antigen-binding protein of the present invention binds may be contained in a fragment of FGFR3 (e.g., human FGFR3b), such as its extracellular domain. Antigen-binding proteins (e.g., antibodies) of the present invention that bind to such epitopes are part of the present disclosure.

[0058] Methods for determining the epitope of an antigen-binding protein, such as an antibody or fragment or polypeptide, include alanine scanning mutation analysis, peptide blot analysis (Reineke (2004) Methods Mol. Biol. 248:443-63), peptide cleavage analysis, crystallography, and NMR analysis. In addition, methods such as epitope excision, epitope extraction, and chemical modification of antigens can be used (Tomer (2000) Prot. Sci. 9:487-496). Another method that can be used to identify the amino acid in a polypeptide with which an antigen-binding protein (e.g., an antibody or fragment or polypeptide) interacts is hydrogen / deuterium exchange detected by mass spectrometry. See, for example, Ehring (1999) Analytical Biochemistry 267:252-259, Engen and Smith (2001) Anal. Chem. 73:256A-265A.

[0059] The present invention includes antigen binding proteins that compete with the antigen binding proteins of the invention (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) for binding to FGFR3 (e.g., the FGFR3b epitopes discussed herein). As used herein, the term "compete" refers to an antigen binding protein (e.g., an antibody or antigen-binding fragment) that binds to an antigen (e.g., FGFR3) and inhibits or blocks the binding of another antigen binding protein (e.g., an antibody or antigen-binding fragment thereof) to the antigen. Unless otherwise stated, this term also includes competition between two antigen-binding proteins, e.g., antibodies, in both orientations, i.e., a first antibody binds to an antigen and blocks binding by a second antibody, and vice versa. Thus, in one embodiment of the present invention, competition occurs in one such orientation. In certain embodiments, a first antigen-binding protein (e.g., an antibody) and a second antigen-binding protein (e.g., an antibody) may bind to the same epitope. Alternatively, the first and second antigen-binding proteins (e.g., antibodies) may bind to different, but overlapping or non-overlapping, epitopes, such that the binding of one inhibits or blocks the binding of the second antibody, for example, through steric hindrance. Competition between antigen-binding proteins (e.g., antibodies) can be measured by methods known in the art, for example, by real-time label-free biolayer interferometry assays. Additionally, binding competition between FGFR3 antigen-binding proteins (eg, monoclonal antibodies (mAbs)) can be determined using a real-time label-free biolayer interferometry assay on an Octet RED384 biosensor (Pall ForteBio Corp.).

[0060] Typically, antibodies or antigen-binding fragments of the present invention, modified in some way, retain the ability to specifically bind to FGFR3 (e.g., FGFR3b), e.g., retain at least 10% of their FGFR3 binding activity (compared to the parent antibody), when activity is expressed on a molar basis. Preferably, antibodies or antigen-binding fragments of the present invention retain at least 20%, 50%, 70%, 80%, 90%, 95%, or 100%, or more, of the FGFR3 binding affinity of the parent antibody. It is also intended that antibodies or antigen-binding fragments of the present invention may include conservative or non-conservative amino acid substitutions (referred to as "conservative variants" or "function-conservative variants" of antibodies) that do not substantially alter their biological activity.

[0061] "Variants" of polypeptides such as immunoglobulin chains (e.g., variants of H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2, including the amino acid sequences specifically described herein) H , V L, HC, or LC, or CDRs thereof) when the comparison is made using the BLAST algorithm and the algorithm parameters are selected to give the largest match between the respective sequences over the entire length of the respective reference sequences (e.g., expectation threshold: 10, word size: 3, maximum match in query range: 0, BLOSUM 62 matrix, gap cost: presence 11, extension 1, conditional composition score matrix adjustment), a reference amino acid sequence described herein (e.g., SEQ ID NOs: 2, 10, 18, 20, 22, 30, 38, 40, 42, 50, 58, 60, 62, 70, 78, 80, 82, 90, 98, 100, 102, 110, 118, 120, 122, 130, 136, 138, 140, 148, 155, 157, 159, 167, 169, 177, 179, 187, 195, 197, 199, 207, 215, 217, 219, 227, 229, or 231) or a polypeptide containing an amino acid sequence that is at least about 70 to 99.9% (e.g., at least 70, 72, 74, 75, 76, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, or 99.9%) identical or similar to any of the amino acid sequences of the polypeptides listed above.

[0062] Additionally, a variant of a polypeptide can comprise the amino acid sequence of a reference polypeptide specifically described herein, except for one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) mutations, e.g., one or more missense mutations (e.g., conservative substitutions), nonsense mutations, deletions, or insertions, of an immunoglobulin chain (e.g., V4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2). H , V L, HC, or LC, or CDRs thereof. See Table A. For example, the present invention provides an immunoglobulin light chain (or VH chain) comprising the amino acid sequence set forth in SEQ ID NO: 10, but having one or more of such mutations. L ) variants, and / or immunoglobulin heavy chains (or V) comprising the amino acid sequence set forth in SEQ ID NO:2 but having one or more of such mutations. H In one embodiment of the present invention, the anti-FGFR3 antigen binding protein comprises an immunoglobulin light chain variant comprising CDR-L1, CDR-L2, and CDR-L3, in which one or more (e.g., one, or two, or three) of such CDRs have one or more of such mutations (e.g., conservative substitutions), and / or an immunoglobulin heavy chain variant comprising CDR-H1, CDR-H2, and CDR-H3, in which one or more (e.g., one, or two, or three) of such CDRs have one or more of such mutations (e.g., conservative substitutions).

[0063] The following references relate to the BLAST algorithm, which is often used for sequence analysis: BLAST ALGORITHMS: Altschul et al. (2005) FEBS J. 272(20):5101-5109; Altschul, SF, et al., (1990) J. Mol. Biol. 215:403-410; Gish, W. et al., (1993) Nature Genet. 3:266-272; Madden, TL, et al., (1996) Meth. Enzymol. 266:131-141; Altschul, SF, et al., (1997) Nucleic Acids Res. 25:3389-3402; Zhang, J., et al., (1997) Genome Res. 7:649-656; Wootton, JC, et al. al., (1993) Comput. Chem. 17:149-163, Hancock, JM et al., (1994) Comput. Appl. Biosci. 10:67-70, ALIGNMENT SCORING SYSTEMS: Dayhoff, MO, et al., “A model of evolutionary change in proteins.” in Atlas of Protein Sequence and Structure,(1978)vol.5,suppl.3.MODayhoff(ed.),pp.345-352,Natl.Biomed.Res.Found.,Washington,DC,Schwartz,RM,et al.,“Matrices for detecting distant relationships.” in Atlas of Protein Sequence and Structure,(1978)vol.5,suppl.3.“MODayhoff(ed.),pp.353-358,Natl.Biomed.Res.Found.,Washington,DC,Altschul,SF,(1991)J.Mol.Biol.219:555-565,States,DJ,et al.,(1991)Methods3:66-70, Henikoff,S.,et al.,(1992)Proc.Natl.Acad.Sci.USA89:10915-10919, Altschul,SF,et al.,(1993)J.Mol.Evol.36:290-300,ALIGNMENT STATISTICS:Karlin,S.,et al.,(1990)Proc.Natl.Acad.Sci.USA 87:2264-2268,Karlin,S.,et al., (1993) Proc. Natl. Acad. Sci. USA 90:5873-5877, Dembo, A., et al., (1994) Ann. Prob.22:2022-2039, and Altschul, SF “Evaluating the statistical significance of multiple distinct local alignments.” in Theoretical and Computational Methods in Genome Research (S. Suhai, ed.), (1997) pp.1-14, Plenum, NY. .

[0064] For example, "conservatively modified variants" or "conservative substitutions" of immunoglobulin chains described herein refer to variants in which there is one or more substitutions of an amino acid in a polypeptide with another amino acid having similar characteristics (e.g., charge, side chain size, hydrophobicity / hydrophilicity, backbone conformation, and rigidity, etc.). Such changes can frequently be made without significantly destroying the biological activity of the antibody or fragment. Those skilled in the art recognize that, in general, single amino acid substitutions in non-essential regions of a polypeptide do not substantially alter biological activity (see, for example, Watson et al., (1987) Molecular Biology of the Gene, The Benjamin / Cummings Pub. Co., p. 224(4 th (See, e.g., J. Am. Chem. Soc. 1999, 14:131-132, 1999). In addition, substitutions of structurally or functionally similar amino acids are unlikely to significantly disrupt biological activity. The present invention includes anti-FGFR3 antigen binding proteins comprising such conservatively modified variant immunoglobulin chains.

[0065] Examples of groups of amino acids with side chains with similar chemical properties include: 1) aliphatic side chains: glycine, alanine, valine, leucine, and isoleucine; 2) aliphatic-hydroxyl side chains: serine and threonine; 3) amide-containing side chains: asparagine and glutamine; 4) aromatic side chains: phenylalanine, tyrosine, and tryptophan; 5) basic side chains: lysine, arginine, and histidine; 6) acidic side chains: aspartic acid and glutamic acid; and 7) sulfur-containing side chains: cysteine ​​and methionine. Alternatively, a conservative substitution is any change that has a positive value in the PAM250 log-likelihood matrix disclosed in Gonnet et al. (1992) Science 256:1443-1445.

[0066] "H4H30063P" ("REGN15684"), "H4H30066P", "H4H30071P", "H4H30089P2", "H4H30093P2", "H4H30102P2", "H4H30076P", "H4H30105P2", "H4H30108P2", "H4H30117P2", "H4H30045P", "H4H30061P", and "H4H30095P2" are listed in Table A unless otherwise stated. and immunoglobulin heavy chain variable regions (V) comprising the amino acid sequence pairs specifically set forth in SEQ ID NOs: 2 and 10, 22 and 30, 42 and 50, 62 and 70, 82 and 90, 102 and 110, 122 and 130, 140 and 148, 159 and 148, 169 and 148, 179 and 187, 199 and 207, and 219 and 227 (or any variant of said sequences), respectively, as set forth in H ) and immunoglobulin light chain variable region (V L), or an immunoglobulin heavy chain (HC) and an immunoglobulin light chain (LC) comprising the amino acid sequence pair specifically set forth in SEQ ID NOs: 18 and 20, 38 and 40, 58 and 60, 78 and 80, 98 and 100, 118 and 120, 136 and 138, 155 and 157, 167 and 157, 177 and 157, 195 and 197, 215 and 217, or 229 and 231 (or any variant of said sequences), as set forth in Table A, or a heavy or V chain comprising its CDRs (CDR-H1 (or variant thereof), CDR-H2 (or variant thereof), and CDR-H3 (or variant thereof)). H and / or a light chain or V comprising its CDRs (CDR-L1 (or a variant thereof), CDR-L2 (or a variant thereof), and CDR-L3 (or a variant thereof)). L and an immunoglobulin light chain (LC) comprising: H is linked to an IgG constant heavy chain domain, e.g., a human IgG constant heavy chain domain (e.g., IgG1 or IgG4 (e.g., containing an S228P and / or S108P mutation)), and / or V L is linked to a light chain constant domain, e.g., a human light chain constant domain (e.g., a lambda or kappa constant light chain domain). Any such immunoglobulin chain (e.g., V H , V L Polynucleotides encoding one or more of the following (HC, HC, and / or LC) form part of the present invention.

[0067] The antibodies and antigen-binding fragments of the invention (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) comprise immunoglobulin chains that include the amino acid sequences (and variants thereof) specifically described herein, as well as cellular and in vitro post-translational modifications to the antibodies or fragments. For example, the present invention includes antibodies and antigen-binding fragments thereof that specifically bind to FGFR3, comprising the heavy and / or light chain amino acid sequences described herein, as well as antibodies and fragments in which one or more asparagine, serine, and / or threonine residues are glycosylated, one or more asparagine residues are deamidated, one or more residues (e.g., Met, Trp, and / or His) are oxidized, the N-terminal glutamine is pyroglutamic acid (pyroE), and / or the C-terminal lysine or other amino acid is deleted.

[0068] The invention provides a container (e.g., a plastic or glass vial with a cap or chromatography column, hollow needle or syringe cylinder) comprising an anti-FGFR3 antigen binding protein of the invention, e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2.

[0069] The present invention also provides an injection device comprising one or more antigen binding proteins (e.g., antibodies or antigen binding fragments) that specifically bind to FGFR3, such as H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2, or pharmaceutical formulations thereof.The injection device can be packaged in a kit.The injection device is a device that introduces a substance into the body of a subject via a parenteral route, for example, intraocularly, intravitreally, intramuscularly, subcutaneously, or intravenously. For example, the injection device may be a syringe or auto-injector (e.g., pre-filled with a pharmaceutical formulation) that includes, for example, a cylinder or barrel for holding the fluid to be injected (e.g., comprising an antibody or fragment thereof or a pharmaceutical formulation thereof), a needle for piercing the skin, blood vessel or other tissue for injection of the fluid, and a plunger for forcing the liquid from the cylinder through the bore of the needle and into the body of the subject.

[0070] Post-translational modifications The anti-FGFR3 antibodies and antigen-binding fragments of the present invention may be post-translationally modified (eg, glycosylated).

[0071] For example, the antibodies and antigen-binding fragments of the present invention may be glycosylated (e.g., N-glycosylated and / or O-glycosylated) or aglycosylated. Typically, antibodies and antigen-binding fragments are glycosylated at the conserved residue N297 of the IgG Fc domain. Some antibodies and fragments contain one or more additional glycosylation sites in the variable region. In one embodiment of the present invention, the glycosylation site is located in the following context: FN 297 S or YN 297 It's in S.

[0072] In one embodiment of the invention, the glycosylation is any one or more of the three different N-glycan types: high mannose, complex, and / or hybrid, which are found on IgG with their respective linkages. Complex and hybrid types exist with core fucosylation, the addition of a fucose residue to the innermost N-acetylglucosamine, and without core fucosylation.

[0073] In one embodiment of the present invention, the antibody or fragment of the present invention is afucosylated. Some IgG1 antibodies rely on Fc-mediated immune effector function, antibody-dependent cellular cytotoxicity (ADCC), as their primary mode of action to deplete tumor cells. This effector function is regulated by N-linked glycosylation in the Fc region of the antibody. In particular, the absence of core fucose on Fc N-glycans has been shown to increase IgG1Fc binding affinity for FcγRIIIa, which is present on immune effector cells such as natural killer cells, resulting in improved ADCC activity.

[0074] The antibodies and antigen-binding fragments of the invention may also be post-translationally modified in other ways, including, for example, Glu or Gln cyclization at the N-terminus, loss of the N-terminal positive charge, Lys variants at the C-terminus, deamidation (Asn to Asp), isomerization (Asp to isoAsp), deamidation (Gln to Glu), oxidation (Cys, His, Met, Tyr, Trp), and / or disulfide bond heterogeneity (shuffling, thioether, and trisulfide formation).

[0075] Polynucleotides and methods of production Polynucleotides include DNA and RNA. The present invention relates to immunoglobulin V sequences, for example, H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, and / or H4H30093P2. H , V L, CDR-H, CDR-L, HC, or LC, optionally operably linked to a promoter or other expression control sequence. For example, the present invention provides SEQ ID NOs: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 17

[0013] The present invention provides any polynucleotide (e.g., DNA) comprising a nucleotide sequence as set forth in any one of claims 7, 139, 141, 143, 145, 147, 149, 151, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, 192, 194, 196, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, or 230. In one embodiment of the present invention, the polynucleotide of the present invention is fused to a secretory signal sequence. Polypeptides encoded by such polynucleotides are also within the scope of the present invention.

[0076] Generally, a "promoter" or "promoter sequence" is a DNA regulatory region capable of binding RNA polymerase in a cell (e.g., directly or through other promoter-binding proteins or substances) and initiating transcription of a coding sequence. Promoters may be operably linked to other expression control sequences, including enhancer and repressor sequences, and / or to a polynucleotide of the invention. Promoters that can be used to control gene expression include the cytomegalovirus (CMV) promoter (U.S. Pat. Nos. 5,385,839 and 5,168,062), the SV40 early promoter region (Benoist, et al., (1981) Nature 290:304-310), the promoter contained in the 3' long terminal repeat of Rous sarcoma virus (Yamamoto, et al., (1980) Cell 22:787-797), the herpes thymidine kinase promoter (Wagner et al., (1981) Proc. Natl. Acad. Sci. USA 78:1441-1445), the regulatory sequence of the metallothionine gene (Brinster, et al., (1982) Nature 296:39-42), the beta-lactamase promoter (VIIIa-Komaroff et al., (1982) Nature 296:39-42), and the SV40 early promoter region (Benoist, et al., (1981) Nature 290:304-310). al., (1978) Proc. Natl. Acad. Sci. USA 75:3727-3731), or the tac promoter (DeBoer et al. (1983) Proc. Natl. Acad. USA 80:21-25; see also "Useful proteins from recombinant bacteria" in Scientific American (1980) 242:74-94;), as well as promoters from yeast or other fungi, such as the Gal4 promoter, the ADC (alcohol dehydrogenase) promoter, the PGK (phosphoglycerol kinase) promoter, and the alkaline phosphatase promoter.

[0077] A polynucleotide encoding a polypeptide is "operably linked" to a promoter or other expression control sequence if, in a cell or other expression system, the sequence directs RNA polymerase-mediated transcription of the coding sequence into RNA, preferably mRNA, which can then be spliced ​​(if it contains introns) and, optionally, translated into the protein encoded by the coding sequence.

[0078] The present invention is H and V L and a polynucleotide comprising the following polynucleotide pair encoding: SEQ ID NO: 1 and SEQ ID NO: 9; SEQ ID NO:21 and SEQ ID NO:29; SEQ ID NO: 41 and SEQ ID NO: 49; SEQ ID NO:61 and SEQ ID NO:69; SEQ ID NO: 81 and SEQ ID NO: 89; SEQ ID NO: 101 and SEQ ID NO: 109; SEQ ID NO: 121 and SEQ ID NO: 129; SEQ ID NO: 139 and SEQ ID NO: 147; SEQ ID NO: 158 and SEQ ID NO: 147; SEQ ID NO: 168 and SEQ ID NO: 147; SEQ ID NO: 178 and SEQ ID NO: 186; SEQ ID NO: 198 and SEQ ID NO: 206; and / or SEQ ID NO: 218 and SEQ ID NO: 226; or two separate polynucleotides each containing one of the sequences SEQ ID NO: 1 and SEQ ID NO: 9; SEQ ID NO:21 and SEQ ID NO:29; SEQ ID NO: 41 and SEQ ID NO: 49; SEQ ID NO:61 and SEQ ID NO:69; SEQ ID NO: 81 and SEQ ID NO: 89; SEQ ID NO: 101 and SEQ ID NO: 109; SEQ ID NO: 121 and SEQ ID NO: 129; SEQ ID NO: 139 and SEQ ID NO: 147; SEQ ID NO: 158 and SEQ ID NO: 147; SEQ ID NO: 168 and SEQ ID NO: 147; SEQ ID NO: 178 and SEQ ID NO: 186; SEQ ID NO: 198 and SEQ ID NO: 206; or SEQ ID NO: 218 and SEQ ID NO: 226.

[0079] The present invention includes polynucleotides comprising the following set of polynucleotides encoding CDR-H1, CDR-H2, CDR-H3, CDR-L1, CDR-L2, and CDR-L3: SEQ ID NOs: 3, 5, 7, 11, 13, and 15; SEQ ID NOs: 23, 25, 27, 31, 33, and 35; SEQ ID NOs: 43, 45, 47, 51, 53, and 55; SEQ ID NOs: 63, 65, 67, 71, 73, and 75; SEQ ID NOs: 83, 85, 87, 91, 93, and 95; SEQ ID NOs: 103, 105, 107, 111, 113, and 115; SEQ ID NOs: 123, 125, 127, 131, 33, and 133; SEQ ID NOs: 141, 143, 415, 149, 151, and 152; SEQ ID NOs: 160, 162, 164, 149, 151, and 152; SEQ ID NOs: 170, 172, 174, 149, 151, and 152; SEQ ID NOs: 180, 182, 184, 188, 190, and 192; SEQ ID NOs: 200, 202, 204, 208, 210, and 212; and / or SEQ ID NOs: 220, 222, 224, 31, 33, and 75; or two separate polynucleotides each comprising one of the following sequences: SEQ ID NOs: 3, 5, and 7; and 11, 13, and 15; SEQ ID NOs: 23, 25, and 27; and 31, 33, and 35; SEQ ID NOs: 43, 45, and 47; and 51, 53, and 55; SEQ ID NOs: 63, 65, and 67; and 71, 73, and 75; SEQ ID NOs: 83, 85, and 87; and 91, 93, and 95; SEQ ID NOs: 103, 105, and 107; and 111, 113, and 115; SEQ ID NOs: 123, 125, and 127; and 131, 33, and 133; SEQ ID NOs: 141, 143, and 415; and 149, 151, and 152; SEQ ID NOs: 160, 162, and 164; and 149, 151, and 152; SEQ ID NOs: 170, 172, and 174; and 149, 151, and 152; SEQ ID NOs: 180, 182, and 184; and 188, 190, and 192; SEQ ID NOs: 200, 202, and 204; and 208, 210, and 212; or SEQ ID NOs: 220, 222, and 224; and 31, 33, and 75.

[0080] The present invention includes polynucleotides comprising the following polynucleotide pair encoding HC and LC: SEQ ID NO: 17 and SEQ ID NO: 19; SEQ ID NO: 37 and SEQ ID NO: 39; SEQ ID NO:57 and SEQ ID NO:59; SEQ ID NO: 77 and SEQ ID NO: 79; SEQ ID NO:97 and SEQ ID NO:99; SEQ ID NO: 117 and SEQ ID NO: 119; SEQ ID NO: 135 and SEQ ID NO: 137; SEQ ID NO: 154 and SEQ ID NO: 156; SEQ ID NO: 166 and SEQ ID NO: 156; SEQ ID NO: 176 and SEQ ID NO: 156; SEQ ID NO: 194 and SEQ ID NO: 196; SEQ ID NO: 214 and SEQ ID NO: 216; and / or SEQ ID NO: 228 and SEQ ID NO: 230; or two separate polynucleotides each comprising one of the following sequences: SEQ ID NO: 17 and SEQ ID NO: 19; SEQ ID NO: 37 and SEQ ID NO: 39; SEQ ID NO:57 and SEQ ID NO:59; SEQ ID NO: 77 and SEQ ID NO: 79; SEQ ID NO:97 and SEQ ID NO:99; SEQ ID NO: 117 and SEQ ID NO: 119; SEQ ID NO: 135 and SEQ ID NO: 137; SEQ ID NO: 154 and SEQ ID NO: 156; SEQ ID NO: 166 and SEQ ID NO: 156; SEQ ID NO: 176 and SEQ ID NO: 156; SEQ ID NO: 194 and SEQ ID NO: 196; SEQ ID NO: 214 and SEQ ID NO: 216; and / or SEQ ID NO: 228 and SEQ ID NO: 230.

[0081] Host cells containing two separate polynucleotides, as discussed above, each integrated into the host cell's chromosomal DNA at different loci or ectopically, such that such polynucleotides are maintained in separate genetic elements, are within the scope of the present invention.

[0082] The present invention includes polynucleotides encoding immunoglobulin polypeptide chains that are variants of the nucleotide sequences specifically described herein. A "variant" polynucleotide refers to a polynucleotide that contains a nucleotide sequence that is at least about 70-99.9% identical (e.g., 70, 72, 74, 75, 76, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9%) to a reference nucleotide sequence described herein when the comparison is performed using the BLAST algorithm with algorithm parameters selected to maximize the match between the respective sequences over the entire length of the respective reference sequences (e.g., expectation threshold: 10, word size: 28, maximum match in query range: 0, match / mismatch score: 1, -2, gap cost: linear). In one embodiment of the present invention, variants of the nucleotide sequences specifically described herein comprise one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) point mutations, insertions (e.g., in-frame insertions), or deletions (e.g., in-frame deletions) of one or more nucleotides. Such mutations may be missense or nonsense mutations in one embodiment of the present invention. In one embodiment of the present invention, such variant polynucleotides encode immunoglobulin polypeptide chains that can be incorporated into anti-FGFR3 antigen-binding proteins, i.e., such proteins retain specific binding to FGFR3.

[0083] Eukaryotic and prokaryotic host cells, including mammalian cells, can be used as hosts for expressing anti-FGFR3 antigen-binding proteins (e.g., antibodies or antigen-binding fragments thereof). Such host cells are well known in the art, and many are available from the American Type Culture Collection (ATCC). These host cells include, among others, Chinese hamster ovary (CHO) cells, NSO, SP2 cells, HeLa cells, baby hamster kidney (BHK) cells, monkey kidney cells (COS), human hepatocellular carcinoma cells (e.g., Hep G2), A549 cells, 3T3 cells, HEK-293 cells, and numerous other cell lines. Mammalian host cells include human, mouse, rat, dog, monkey, pig, goat, cow, horse, and hamster cells. Other cell lines that can be used are insect cell lines (e.g., Spodoptera frugiperda or Trichoplusia ni), amphibian cells, bacterial cells, plant cells, and fungal cells.Examples of fungal cells include Pichia, Pichia pastoris, Pichia finlandica, Pichia trehalophila, Pichia koclamae, Pichia membranaefaciens, Pichia minuta (Ogataea minuta, Pichia lindneri), Pichia opuntiae, Pichia thermotolerans, Pichia salictaria, Pichia guercuum, Pichia pijperi, Pichia stiptis, Pichia methanolica, Pichia sp., Saccharomyces cerevisiae, Saccharomyces sp., Hansenula polymorpha, Kluyveromyces sp., Kluyveromyces lactis, Candida albicans, Aspergillus nidulans, Aspergillus niger, Aspergillus oryzae, Trichoderma reesei, Chrysosporium lucknowense, Fusarium sp., Fusarium gramineum, Fusarium venenatum, Physcomitrella patens, and Neurospora crassa. The present invention relates to an antigen binding protein such as H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2 (e.g., as discussed herein). H , V L In one embodiment of the present invention, the host cell comprises two separate polynucleotides, one encoding a V, HC, LC, or CDR (or variants thereof), and / or one or more immunoglobulin chains thereof.H and the other is V L or one encodes HC and the other encodes LC.

[0084] The present invention also includes cells expressing FGFR3 or an antigenic fragment or fusion thereof (e.g., His6 (SEQ ID NO: 235), Fc (e.g., mouse Fc (mFc)), myc, or mycmycHis6 (mmh)) bound by an antigen binding protein (e.g., an antibody or antigen-binding fragment thereof) of the invention, e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2, including, for example, cells in a subject's body or in vitro. In addition, the present invention also provides complexes comprising an anti-FGFR3 antigen-binding protein, e.g., an antibody or antigen-binding fragment thereof, as discussed herein, complexed with an FGFR3 polypeptide or antigen-fragment thereof, or a fusion thereof, and / or a secondary antibody or antigen-binding fragment thereof (e.g., a detectably labeled secondary antibody) that specifically binds to the anti-FGFR3 antibody or fragment. In one embodiment of the present invention, the complex is in vitro, e.g., immobilized on a solid substrate), or within the body of a subject.

[0085] In one embodiment of the invention, the myc tag has the amino acid sequence EQKLISEEDLGG (SEQ ID NO: 234), the His6 (SEQ ID NO: 235), or hexahistidine (SEQ ID NO: 235) tag has the amino acid sequence HHHHHH (SEQ ID NO: 235), the mmh tag has the amino acid sequence EQKLISEEDLGGEQKLISEEDLHHHHHH (SEQ ID NO: 236), and the mouse Fc tag has the amino acid sequence EPRGPTIKPCPPCKCPAPNLLGGPSVFIFPPKIKDVLMISLSPIVTCVVVDVSEDDPDVQISWFVNNVEVHTAQTQTHREDYNSTLRVVSALPIQHQDWMSGKEFKCKVNNKDLPAPIERTISKPKGSVRAPQVYVLPPPEEEMTKKQVTLTCMVTDFMPEDIYVEWTNNGKTELNYKNTEPVLDSDGSYFMYSKLRVEKKNWVERNSYSCSVVHEGLHNHHTTKSFSRTPGK (sequence number 237).

[0086] The recombinant anti-FGFR3 antigen-binding proteins, e.g., antibodies and antigen-binding fragments, disclosed herein can also be produced in an E. coli / T7 expression system. In this embodiment, the HC, LC, V of a polynucleotide encoding an anti-FGFR3 antibody immunoglobulin molecule of the present invention (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) can be expressed in an E. coli / T7 expression system. H , and / or V L, or CDRs thereof) can be inserted into a pET-based plasmid and expressed in an E. coli / T7 system. For example, the invention includes methods for expressing an antibody or antigen-binding fragment thereof, or an immunoglobulin chain(s), in a host cell (e.g., a bacterial host cell such as E. coli such as BL21 or BL21DE3), comprising expressing T7 RNA polymerase in the cell, the cell comprising a polynucleotide encoding the immunoglobulin chain (e.g., comprising any one or more of the nucleotide sequences of SEQ ID NOs: 1, 3, 5, 7, 9, 11, 13, 15, 17, or 19, or a variant thereof) operably linked to a T7 promoter. For example, in one embodiment of the invention, a bacterial host cell such as E. coli comprises a polynucleotide encoding a T7 RNA polymerase gene operably linked to a lac promoter, and expression of the polymerase and chain(s) is induced by incubating the host cell with IPTG (isopropyl-beta-D-thiogalactopyranoside). See US4952496 and US5693489, or Studier & Moffatt, Use of bacteriophage T7 RNA polymerase to direct selective high-level expression of cloned genes, J. Mol. Biol. 1986 May 5;189(1):113-30.

[0087] Several methods for producing recombinant antibodies are known in the art. One example of a method for the recombinant production of antibodies is disclosed in US4816567.

[0088] Transformation can be by any known method for introducing polynucleotide into host cell.Methods for introducing heterologous polynucleotide into mammalian cells are well known in the art, including dextran-mediated transfection, calcium phosphate precipitation, polybrene-mediated transfection, protoplast fusion, electrophoresis, encapsulation of polynucleotide(s) in liposome, biolistic injection, and direct microinjection of DNA into nucleus.In addition, nucleic acid molecules can be introduced into mammalian cells by viral vector.Methods for transforming cells are well known in the art.See, for example, U.S. Patent Nos. 4,399,216, 4,912,040, 4,740,461, and 4,959,455. Accordingly, the present invention provides a recombinant method for producing an anti-FGFR3 (e.g., monomeric or dimeric FGFR3b) antigen binding protein, such as an antibody or antigen-binding fragment thereof, or immunoglobulin chain thereof, of the invention, comprising: (i) introducing into a host cell an antigen binding protein, e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2, wherein the polynucleotides are in a vector and / or integrated into a host cell chromosome and / or operably linked to a promoter; (ii) culturing the host cell (e.g., CHO, Pichia, or Pichia pastoris) under conditions favorable for expression of the polynucleotides; and (iii) optionally isolating the antigen-binding protein (e.g., antibody or antigen-binding fragment) or chain from the host cell and / or from the medium in which the host cell is grown.When producing an antigen-binding protein (e.g., an antibody or antigen-binding fragment) comprising multiple immunoglobulin chains, for example, an antibody comprising two immunoglobulin heavy chains and two immunoglobulin light chains, co-expressing the chains in a single host cell results in the association of the chains intracellularly, on the cell surface, or extracellularly, for example, when such chains are secreted to form the antigen-binding protein (e.g., an antibody or antigen-binding fragment). The methods of the present invention include methods in which only an immunoglobulin heavy chain or only an immunoglobulin light chain, or both (e.g., any of those discussed herein, including mature fragments and / or variable domains thereof) are expressed in a cell. Such single chains are useful, for example, as intermediates in the expression of antibodies or antigen-binding fragments comprising such chains. For example, the present invention also includes anti-FGFR3 antigen-binding proteins, such as antibodies and antigen-binding fragments thereof, that are the products of the production methods described herein and, optionally, the purification methods described herein.

[0089] In one embodiment of the present invention, methods for producing anti-FGFR3 (e.g., monomeric or dimeric FGFR3b) antigen binding proteins, e.g., antibodies or antigen-binding fragments thereof, include methods for purifying the antigen binding protein, e.g., by column chromatography, precipitation, and / or filtration. As discussed, the products of such methods also form part of the present invention.

[0090] Preparation of human antibodies The anti-FGFR3 (e.g., monomeric or dimeric FGFR3b) antibodies and antigen-binding fragments of the present invention (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) can be fully human antibodies and fragments. Methods for generating monoclonal antibodies, including fully human monoclonal antibodies, are known in the art. Any such known method can be used in the context of the present invention to generate human antibodies that specifically bind to human FGFR3.

[0091] For example, using VELOCIMMUNE™ technology or any other similar known method for generating fully human monoclonal antibodies, high-affinity chimeric antibodies against FGFR3 with human variable regions and mouse constant regions are first isolated. As described in the experimental section below, the antibodies are characterized and selected for desired characteristics, including affinity, ligand-blocking activity, selectivity, epitope, etc. If necessary, the mouse constant region is replaced with a desired human constant region, such as wild-type or modified IgG1 or IgG4, to generate a fully human anti-FGFR3 antibody. While the selected constant region can vary depending on the specific application, high-affinity antigen-binding and target specificity characteristics reside in the variable region. In certain cases, fully human anti-FGFR3 antibodies are directly isolated from antigen-positive B cells. See, for example, US6596541, Regeneron Pharmaceuticals, VELOCIMMUNE®.

[0092] Anti-FGFR3 antibodies, including Fc variants According to certain embodiments of the present invention, anti-FGFR3 (e.g., monomeric or dimeric FGFR3b) antibodies and antigen-binding fragments (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) are provided, For example, the present invention includes an Fc domain containing one or more mutations that enhance or decrease antibody binding to the FcRn receptor at acidic pH compared to neutral pH (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2). For example, the present invention includes anti-FGFR3 antibodies containing mutations in the CH2 or CH3 region of the Fc domain, where the mutation(s) increase the affinity of the Fc domain for FcRn in an acidic environment (e.g., in endosomes at a pH ranging from about 5.5 to about 6.0). Such mutations may result in an increase in the serum half-life of the antibody when administered to an animal.

[0093] Non-limiting examples of such Fc modifications include, for example, modifications at the following positions: ●250th place (for example, E or Q), ● 250th and 428th positions (e.g., L or F), ● 252nd place (e.g., L / Y / F / W or T), Position 254 (e.g., S or T), and / or • Modification at position 256 (e.g., S / R / Q / E / D, or T), and / or location: Positions 428 and / or 433 (e.g., H / L / R / S / P / Q, or K), and / or • Modification at position 434 (e.g., A, W, H / F, or Y); and / or location: ●Modifications at positions 250 and / or 428, and / or location: Positions 307 or 308 (e.g., 308F, V308F), and / or ●Modification at position 434 is one example.

[0094] In one embodiment of the invention, the modification is 428L (e.g., M428L position) and 434S (e.g., N434S) modifications, 428L, 259I (e.g., V259I), and 308F (e.g., V308F) modifications; • 433K (e.g., H433K) and 434 (e.g., 434Y) modifications; • 252, 254, and 256 (e.g., 252Y, 254T, and 256E) modifications; 250Q and 428L modifications (e.g., T250Q and M428L), and / or • Contains 307 and / or 308 modifications (e.g., 308F or 308P).

[0095] For example, the present invention provides ●250Q and 248L (e.g., T250Q and M248L), ● 252Y, 254T, and 256E (e.g., M252Y, S254T, and T256E), • 257I and 311I (e.g., P257I and Q311I), • 257I and 434H (e.g., P257I and N434H), ●376V and 434H (e.g., D376V and N434H), ●307A, 380A, and 434A (e.g., T307A, E380A, and N434A), 428L and 434S (e.g., M428L and N434S), and - Includes anti-FGFR3 antibodies comprising an Fc domain containing one or more pairs or groups of mutations selected from the group consisting of 433K and 434F (e.g., H433K and N434F).

[0096] In yet another embodiment, the modifications include a 265A (eg, D265A) and / or a 297A (eg, N297A) modification.

[0097] In one embodiment of the present invention, the heavy chain constant domain is gamma 4 containing an S228P and / or S108P mutation. See Angal et al., A single amino acid substitution abolishes the heterogeneity of chimeric mouse / human (IgG4) antibody, Mol Immunol. 1993 Jan;30(1):105-108.

[0098] All possible combinations of the aforementioned Fc domain mutations, and other mutations in the antibody variable domains disclosed herein, are contemplated as being within the scope of the present invention.

[0099] The anti-FGFR3 antibodies of the present invention may comprise a modified Fc domain with reduced effector function. As used herein, a "modified Fc domain with reduced effector function" refers to any Fc portion of an immunoglobulin that has been modified, mutated, truncated, or the like, compared to a wild-type, naturally occurring Fc domain, such that the molecule comprising the modified Fc exhibits a reduced severity or degree of at least one effect selected from the group consisting of cell-killing (e.g., ADCC and / or CDC), complement activation, phagocytosis, and opsonization, compared to a comparator molecule comprising a wild-type, naturally occurring version of the Fc portion. In certain embodiments, a "modified Fc domain with reduced effector function" is an Fc domain with reduced or attenuated binding to an Fc receptor (e.g., FcγR).

[0100] In certain embodiments of the present invention, the modified Fc domain is a variant IgG1 Fc or variant IgG4 Fc comprising a substitution in the hinge region. For example, a modified Fc for use in the context of the present invention may comprise a variant IgG1 Fc in which at least one amino acid in the IgG1 Fc hinge region is replaced with the corresponding amino acid in an IgG2 Fc hinge region. Alternatively, a modified Fc for use in the context of the present invention may comprise a variant IgG4 Fc in which at least one amino acid in the IgG4 Fc hinge region is replaced with the corresponding amino acid in an IgG2 Fc hinge region. Non-limiting exemplary modified Fc regions that may be used in the context of the present invention are described in U.S. Patent Application Publication No. 2014 / 0243504 (the disclosure of which is incorporated herein by reference in its entirety), as well as any functionally equivalent variants of the modified Fc regions described therein.

[0101] The present disclosure also includes antigen-binding proteins, antibodies, or antigen-binding fragments comprising the HCVRs and chimeric heavy chain constant (CH) regions described herein, where the chimeric CH region comprises segments derived from CH regions of multiple immunoglobulin isotypes. For example, an antibody of the present disclosure may comprise a chimeric CH region comprising part or all of the CH2 domain from a human IgG1, human IgG2, or human IgG4 molecule combined with part or all of the CH3 domain from a human IgG1, human IgG2, or human IgG4 molecule. According to certain embodiments, an antibody of the present disclosure comprises a chimeric CH region with a chimeric hinge region. For example, the chimeric hinge may comprise an "upper hinge" amino acid sequence derived from a human IgG1, IgG2, or IgG4 hinge region (amino acid residues 216-227 according to EU numbering) combined with a "lower hinge" sequence derived from a human IgG1, IgG2, or IgG4 hinge region (amino acid residues 228-236 according to EU numbering). According to certain embodiments, the chimeric hinge region comprises amino acid residues derived from a human IgG1 upper hinge or a human IgG4 upper hinge and amino acid residues derived from a human IgG2 lower hinge. Antibodies comprising the chimeric CH regions described herein, in certain embodiments, exhibit modified Fc effector functions without adversely affecting the therapeutic or pharmacokinetic properties of the antibody. (See, e.g., WO2014 / 022540.)

[0102] Other modified Fc domains and Fc modifications that may be used in the context of the present invention include any of the modifications described in US2014 / 0171623, US8,697,396, US2014 / 0134162, WO2014 / 043361, the disclosures of which are incorporated herein by reference in their entireties. Methods for constructing antibodies or other antigen-binding fusion proteins comprising modified Fc domains described herein are known in the art.

[0103] In some cases, the anti-FGFR3 antibody may contain one or more mutations in the framework region, for example, the CH1 domain, CH2 domain, CH3 domain, hinge region, or a combination thereof. In some embodiments, the one or more mutations are for stabilizing the antibody and / or increasing half-life. In some embodiments, the one or more mutations are for modulating Fc receptor interaction, reducing or eliminating Fc effector function such as FcyR, antibody-dependent cell-mediated cytotoxicity (ADCC), or complement-dependent cytotoxicity (CDC). In additional embodiments, the one or more mutations are for modulating glycosylation.

[0104] In some embodiments, one, two, or more mutations (e.g., amino acid substitutions) are introduced into the Fc region (e.g., the CH2 domain (residues 231-340 of human IgG1), and / or the CH3 domain (residues 341-447 of human IgG1), and / or hinge region, numbered according to the Kabat numbering system (e.g., EU index of Kabat) of an antibody described herein, to alter one or more functional properties of the antibody, such as serum half-life, complement fixation, Fc receptor binding, and / or antigen-dependent cellular cytotoxicity. In some embodiments, One, two, or more mutations (e.g., amino acid substitutions) are introduced into the hinge region of the Fc region (CH1 domain) to alter (e.g., increase or decrease) the number of cysteine ​​residues in the hinge region, as described, for example, in U.S. Patent No. 5,677,425. The number of cysteine ​​residues in the hinge region of the CH1 domain can be altered, for example, to facilitate assembly of the light and heavy chains, or to alter (e.g., increase or decrease) the stability of the antibody, or to facilitate linker conjugation.

[0105] In some embodiments, one, two, or more amino acid mutations (i.e., substitutions, insertions, or deletions) are introduced into an IgG constant domain, or an FcRn-binding fragment thereof (preferably an Fc or hinge-Fc domain fragment), to alter (e.g., decrease or increase) the half-life of the antibody in vivo. For examples of mutations that will alter (e.g., decrease or increase) the half-life of an antibody in vivo, see, e.g., PCT Publication Nos. WO 02 / 060919, WO 98 / 23289, and WO 97 / 34631, as well as U.S. Patent Nos. 5,869,046, 6,121,022, 6,277,375, and 6,165,745. In some embodiments, the Fc region comprises a mutation at residue position L234, L235, or a combination thereof. In some embodiments, the mutation comprises L234 and L235. In some embodiments, the mutation comprises L234A and L235A.

[0106] Immunoconjugates The present invention encompasses anti-FGFR3 (e.g., monomeric or dimeric FGFR3b) antigen binding proteins, e.g., antibodies or antigen-binding fragments, conjugated to another moiety, e.g., a therapeutic moiety ("immunoconjugate") (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2). In one embodiment of the present invention, the anti-FGFR3 antigen binding protein, e.g., antibody or antigen-binding fragment, is conjugated to any of the additional therapeutic agents described herein. As used herein, the term "immunoconjugate" refers to an antigen-binding protein, e.g., an antibody or antigen-binding fragment, that is chemically or biologically linked to another antigen-binding protein, a drug, a radioactive agent, a reporter moiety, an enzyme, a peptide, a protein, or a therapeutic agent.

[0107] Treatment and Administration The present invention provides methods for treating or preventing an FGFR3-mediated condition in a subject, the method comprising administering to the subject a therapeutically effective amount of an anti-FGFR3 (e.g., a monomeric or dimeric FGFR3b) antigen binding protein (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), optionally together with an additional therapeutic agent.

[0108] An FGFR3-mediated condition is any condition that is mediated at least in part by the activity of FGFR3, e.g., the tyrosine kinase activity of FGFR3, or the activity of a molecule downstream of FGFR3 (e.g., the CD73 or MEK pathway in tumor cells that express FGFR3).

[0109] FGFR3-mediated conditions can also include T cell suppression mediated by tumor cells expressing FGFR3, such as adenosine-mediated suppression of T cells via the A2A receptor, where CD73 catalyzes, for example, the conversion of AMP to adenosine. CD73 (NT5E, ecto-5'-nucleotidase) is a glycosylphosphatidylinositol (GPI)-anchored cell surface enzyme that plays an important role in the purinergic signaling pathway by dephosphorylating AMP (adenosine monophosphate) to adenosine. While extracellular adenosine itself is involved in tumor immune evasion and tumor cell invasion, the non-enzymatic functions of CD73 are associated with cell adhesion and tumor cell migration.

[0110] FGFR3-mediated conditions include, for example: Cancer Bladder cancer Brain cancer Breast cancer Cervical cancer Colon cancer Endometrial cancer Stomach cancer Head and neck cancer Kidney cancer Lung cancer Multiple myeloma Ovarian cancer Pancreatic cancer Urothelial cancer ●Achondroplasia Crouzon syndrome with acanthosis nigricans ●Epidermal nevus ●Chondroplasia Lacrimal-Ear-Dental-Digital (LADD) Syndrome Muenke syndrome Severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN) and / or • Thanatophoric bone dysplasia.

[0111] Achondroplasia is a form of short-limbed dwarfism. Crouzon syndrome with acanthosis nigricans is a condition that causes premature fusion of the skull bones (craniosynostosis), resulting in a deformed head and distinctive facial features, as well as a skin abnormality called acanthosis nigricans, characterized by thick, dark, velvety skin in the folds and creases of the body. Epidermal nevi are abnormal skin growths composed of skin cells called keratinocytes. Hypochondroplasia is a milder form of short-limbed dwarfism than achondroplasia. Lacrimal-ear-tooth-digital (LADD) syndrome is an extremely rare genetic disorder characterized by abnormalities affecting the lacrimal and salivary glands and ducts, ears, teeth, and fingers and toes. The most common findings involve malformations of the network of structures in the eye that secrete and drain tears from the eye (lacrimal apparatus), as well as abnormalities of the forearms and fingers. Specific symptoms can vary greatly from person to person. LADD syndrome may occur sporadically or be inherited in an autosomal dominant pattern. Muenke syndrome is a condition resulting in craniosynostosis, causing head deformity and distinctive facial features. Additional signs and symptoms may include hearing loss, subtle limb abnormalities, and developmental delay. SADDAN (Severe Achondroplasia with Developmental Delay and Acanthosis Nigricans) is characterized by short-limbed dwarfism (achondroplasia), severe developmental delay, and thick, dark, velvety skin. Thanatophoric dysplasia is a severe skeletal disorder characterized by very short limbs and extra (redundant) skin folds on the arms and legs. Other features of this condition include a narrow chest, short ribs, underdeveloped lungs, and an enlarged head with a large forehead and prominent, widely spaced eyes. Bladder cancer includes non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC).

[0112] An effective or therapeutically effective amount of an anti-FGFR3 antigen binding protein (e.g., an antibody or antigen-binding fragment) for treating or preventing an FGFR3-mediated condition refers to an amount of antigen binding protein sufficient to alleviate one or more signs and / or symptoms of the disease or condition in the treated subject, whether by inducing regression or elimination of such signs and / or symptoms or by inhibiting the progression of such signs and / or symptoms. In one embodiment of the present invention, an effective or therapeutically effective amount of anti-FGFR3 antigen binding protein is about 2-30 mg / kg. This dose may be administered, for example, about once a month. The amount of the dose may vary depending on the age and size of the subject to be administered, the target disease, condition, route of administration, etc. In certain embodiments, an initial dose may be followed by administration of a second or multiple subsequent doses of the antigen binding protein in an amount that may be about the same as, less than, or greater than the initial dose, with subsequent doses spaced apart by several days, weeks, or months.

[0113] The present invention provides a method for administering an anti-FGFR3 (e.g., a monomeric or dimeric FGFR3b) antigen-binding protein, e.g., an antibody or antigen-binding fragment thereof (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) to a subject, the method comprising introducing the protein or a pharmaceutical formulation thereof into the subject's body. For example, in one embodiment of the present invention, the method comprises puncturing the subject's body, e.g., with the needle of a syringe, and injecting the antigen binding protein or a pharmaceutical formulation thereof into the subject's body (e.g., into the subject's eye, vein, artery, muscle tissue, or subcutaneous tissue).

[0114] As used herein, the term "subject" refers to a mammal (e.g., rat, mouse, cat, dog, cow, sheep, horse, goat, rabbit), preferably a human, that requires prevention and / or treatment of an FGFR3-mediated condition. The subject may have an FGFR3-mediated condition or may be predisposed to developing such a condition. In one embodiment of the present invention, the subject has an FGFR3 genotype selected from the following: S249C, R248C, G372C, Y375C, K650E, and / or FGFR3-TACC3 (e.g., heterozygous or homozygous).

[0115] Combinations and Pharmaceutical Formulations The present invention provides compositions comprising an anti-FGFR3 (e.g., monomeric or dimeric FGFR3b) antigen-binding protein, e.g., an antibody or antigen-binding fragment (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), together with one or more other components, as well as methods of using and making such compositions. Pharmaceutical formulations comprising an anti-FGFR3 antigen-binding protein and a pharmaceutically acceptable carrier or excipient are also part of the present invention.

[0116] To prepare a pharmaceutical formulation of an anti-FGFR3 antigen binding protein, e.g., antibodies and antigen-binding fragments thereof (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), the antigen binding protein is mixed with a pharmaceutically acceptable carrier or excipient. For example, Remington's Pharmaceutical Sciences and US Pharmacopeia: National Formulary, Mack Publishing Company, Easton, Pa. (1984), Hardman, et al. (2001) Goodman and Gilman's The Pharmacological Basis of Therapeutics, McGraw-Hill, New York, NY, Gennaro (2000) Remington: The Science and Practice of Pharmacy, Lippincott, Williams, and Wilkins, New York, NY, Avis, et al. (eds.) (1993) Pharmaceutical Dosage Forms: Parenteral Medications, Marcel Dekker, NY, Lieberman, et al. (eds.) (1990) Pharmaceutical Dosage Forms: Tablets, Marcel Dekker, NY, Lieberman, et al. (eds.) (1990) Pharmaceutical Dosage Forms:Disperse See, for example, "Systems," Marcel Dekker, NY; Weiner and Kotkoskie (2000) "Excipient Toxicity and Safety," Marcel Dekker, Inc., New York, NY. In one embodiment of the present invention, the pharmaceutical formulation is sterile. Such compositions are part of the present invention.

[0117] Pharmaceutical formulations of the invention comprise an anti-FGFR3 antigen binding protein (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2) and a pharmaceutically acceptable carrier (e.g., including water and a buffer).

[0118] The scope of the present invention includes dried (e.g., lyophilized) compositions comprising anti-FGFR3 antigen-binding proteins, e.g., antibodies or antigen-binding fragments thereof (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), or pharmaceutical formulations thereof (comprising a pharmaceutically acceptable carrier but substantially lacking water).

[0119] In further embodiments of the invention, the additional therapeutic agent administered to a subject in conjunction with an anti-FGFR3 antigen binding protein disclosed herein, e.g., an antibody or antigen-binding fragment thereof (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), is selected from the group consisting of antibodies, antibodies, and antibodies to FGFR3. th The test is administered to the subject according to the following standard:

[0120] The mode of administration of an anti-FGFR3 antigen binding protein or composition thereof can vary, including parenteral, non-parenteral, oral, rectal, transmucosal, enteral, parenteral, intramuscular, subcutaneous, intradermal, intramedullary, intrathecal, direct intraventricular, intravenous, intraperitoneal, intranasal, intraocular, inhalation, insufflation, topical, dermal, intraocular, intravitreal, transdermal, or intra-arterial.

[0121] The present invention provides a container (e.g., a plastic or glass vial with a cap or chromatography column, hollow needle or syringe cylinder) containing a pharmaceutical formulation comprising an anti-FGFR3 antigen binding protein, e.g., any of the antibodies or antigen-binding fragments thereof (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), or a pharmaceutically acceptable carrier thereof.

[0122] The present invention includes combinations comprising an anti-FGFR3 antigen binding protein, e.g., an antibody of the invention or an antigen-binding fragment thereof (e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2), together with one or more additional therapeutic agents. The anti-FGFR3 antigen binding protein and the additional therapeutic agent can be present in a single composition or in separate compositions. For example, in one embodiment of the present invention, the additional therapeutic agent is a cancer therapeutic agent. In one embodiment of the present invention, the additional therapeutic agent is: FGFR inhibitors (e.g., erdafitinib) Pemigatinib Infigratinib Rogaratinib Dexamethasone Alkylating drugs (e.g., altretamine, trabectedin, or busulfan) Nitrosoureas (e.g., carmustine or lomustine) • Cytotoxic antibiotics (e.g., anthracyclines, doxorubicin, valrubicin, bleomycin, or dactinomycin) Antimetabolites (e.g., methotrexate, floxuridine, clofarabine, or pralatrexate) Vinca alkaloids (e.g., vinblastine, vinorelbine, vincristine, or vindesine), Photodynamic drugs (e.g., porfimer sodium or aminolevulinic acid) Platinum drugs (cisplatin or phenanthriplatin) Taxanes (e.g., paclitaxel or docetaxel) Topoisomerase inhibitors (e.g., irinotecan, topotecan, etoposide, or teniposide) ziv-aflibercept • Anticancer antibodies (e.g., rituximab, trastuzumab, cetuximab, cemiplimab, pembrolizumab, panitumumab, or bevacizumab).

[0123] As discussed herein, the present invention includes methods for treating or preventing an FGFR3-mediated condition in a subject in need thereof by administering an anti-FGFR3 antigen binding protein, e.g., H4H30063P, H4H30089P2, H4H30071P, H4H30066P, H4H30102P2, H4H30076P, H4H30105P2, H4H30108P2, H4H30117P2, H4H30045P, H4H30061P, H4H30095P2, or H4H30093P2 (which may be administered in conjunction with an additional therapeutic agent).

[0124] The term "in association with" indicates that a component anti-FGFR3 antigen-binding protein (e.g., an antibody of the present invention or antigen-binding fragment thereof) can be formulated with another agent (e.g., methotrexate) in a single composition, e.g., for simultaneous delivery, or can be formulated separately in two or more compositions (e.g., a kit including each component). Components that are administered together can be administered to a subject at a time that is different from when the other components are administered, e.g., each administration can be given non-concurrently, spaced apart (e.g., separately or sequentially) over a given period of time. Separate components that are administered together can be administered sequentially, essentially simultaneously, during the same administration session. Furthermore, separate components that are administered in association with each other can be administered to a subject by the same or different routes. [Example]

[0125] Example 1: Binding Kinetics The Biacore binding kinetics of anti-FGFR3 antibodies to monomeric human FGFR3b, cynomolgus monkey FGFR3b, mouse FGFR3b, human FGFR3c, and dimeric human FGFR3b ectodomain recombinant proteins in an antibody capture format were analyzed at 25°C.

[0126] The equilibrium dissociation constants (K) of binding of human FGFR3b expressed with a C-terminal myc-myc-hexahistidine tag (hFGFR3b.mmH, REGN3152), or cynomolgus monkey FGFR3b expressed with a C-terminal myc-myc-hexahistidine tag (mfFGFR3b.mmH, REGN3521), or mouse FGFR3b expressed with a C-terminal myc-myc-hexahistidine tag (mFGFR3b.mmH, REGN3215), or human FGFR3c expressed with a C-terminal myc-myc-hexahistidine tag (hFGFR3c.mmH, REGN3155), or human FGFR3b expressed with a C-terminal mouse Fc tag (hFGFR3b.mFc, REGN3153) to purified anti-FGFR3 antibodies were measured. DThe binding activity (RI) of the CM5 Biacore sensor was determined using real-time surface plasmon resonance biosensor technology on a Biacore 3000 or Biacore 4000 instrument. The surface of the CM5 Biacore sensor was derivatized by amine coupling with a monoclonal mouse anti-human Fc antibody (REGN2567). All Biacore binding studies were performed in a buffer consisting of 0.01 M HEPES (pH 7.4), 0.15 M NaCl, 3 mM EDTA, and 0.05% v / v surfactant P20 (HBS-EP running buffer). Different concentrations of monomeric protein prepared in HBS-EP running buffer (ranging from 90 nM to 3.33 nM in a 3-fold serial dilution) or dimeric protein (hFGFR3b.mFc, REGN3153) prepared in HBS-EP running buffer (ranging from 30 nM to 10 nM in a 3-fold serial dilution) were injected over the captured anti-FGFR3 antibody at a flow rate of 30 μL / min. Antibody-reagent association was monitored for 5 min, while dissociation in HBS-EP running buffer was monitored for 10 min. At the end of each cycle, the anti-FGFR3 antibody capture surface was regenerated using a 10-s injection of 20 mM phosphoric acid. All binding kinetics experiments were performed at 25°C.

[0127] Specific SPR-Biacore sensorgrams were obtained by a double-referencing procedure. Double-referencing was performed by first subtracting the signal of each injection on the reference surface (anti-hFc) from the signal on the experimental surface (anti-hFc-captured anti-FGFR3 antibody), thereby removing the contribution of refractive index changes. In addition, injections of running buffer were performed to subtract signal changes due to dissociation of the captured antibody from the coupled anti-hFc surface. The kinetic binding rate constant (k a ) and dissociation rate constant (k d The binding-dissociation equilibrium constant (K D ) and dissociation half-life (t1 / 2) were calculated from the kinetic rate constants as follows:

number

[0128] The results of the monomer kinetics are shown in Tables 1-1 to 1-4. The results of the dimer kinetics are presented in Table 1-5.

[0129] REGN3152 (human FGFR3b (hFGFR3b.mmH) expressed with a C-terminal myc-myc-hexahistidine tag) ESLGTEQRVVGRAAEVPGPEPGQQEQLVFGSGDAVELSCPPPGGGPMGPTVWVKDGTGLVPSERVLVGPQRLQVLNASHEDSGAYSCRQRLTQRVLCHFSVRVTDAPSSGDDEDGEDEAEDTGVDTGAPYWTRPERMDKKLLAVPAANTVRFRCPAAGNPTPSISWLKNGREFRGEHRIGGIKLRHQQWSLVMESVVPSDRGNYTCVVENKFGSIRQTYTLDVLERSPHRPILQAGLPANQTAVLGSDVEFHCKVYSDAQPHIQWLKHVEVNGSKVGPDGTPYVTVLKSWISESVEADVRLRLANVSERDGGEYLCRATNFIGVAEKAFWLSVHGPRAAEEELVEADEAGSVYAGEQKLISEEDLGGEQKLISEEDLHHHHHH (SEQ ID NO: 238)

[0130] REGN3153 (human FGFR3b expressed with a C-terminal mouse Fc tag (hFGFR3b.mFc)) (SEQ ID NO: 239)

[0131] REGN3215 (mouse FGFR3b (mFGFR3b.mmH) expressed with a C-terminal myc-myc-hexahistidine tag) EPPGPEQRVVRRAAEVPGPEPSQQEQVAFGSGDTVELSCHPPGGAPTGPTVWAKDGTGLVASHRILVGPQRLQVLNASHEDAGVYSCQHRLTRRVLCHFSVRVTDAPSSGDDEDGEDVAEDTGAPYWTRPERMDKKLLAVPAANTVRFRCPAAGNPTPSISWLKNGKEFRGEHRIGGIKLRHQQWSLVMESVVPSDRGNYTCVVENKFGSIRQTYTLDVLERSPHRPILQAGLPANQTAILGSDVEFHCKVYSDAQPHIQWLKHVEVNGSKVGPDGTPYVTVLKSWISENVEADARLRLANVSERDGGEYLCRATNFIGVAEKAFWLRVHGPQAAEEELMETDEAGSVYAGEQKLISEEDLGGEQKLISEEDLHHHHHH (SEQ ID NO: 240)

[0132] REGN3155 (human FGFR3c (hFGFR3c.mmH) expressed with a C-terminal myc-myc-hexahistidine tag) ESLGTEQRVVGRAAEVPGPEPGQQEQLVFGSGDAVELSCPPPGGGPMGPTVWVKDGTGLVPSERVLVGPQRLQVLNASHEDSGAYSCRQRLTQRVLCHFSVRVTDAPSSGDDEDGEDEAEDTGVDTGAPYWTRPERMDKKLLAVPAANTVRFRCPAAGNPTPSISWLKNGREFRGEHRIGGIKLRHQQWSLVMESVVPSDRGNYTCVVENKFGSIRQTYTLDVLERSPHRPILQAGLPANQTAVLGSDVEFHCKVYSDAQPHIQWLKHVEVNGSKVGPDGTPYVTVLKTAGANTTDKELEVLSLHNVTFEDAGEYTCLAGNSIGFSHHSAWLVVLPAEEELVEADEAGSVYAGEQKLISEEDLGGEQKLISEEDLHHHHHH (SEQ ID NO: 241) REGN3521 (mf FGFR3b ecto(R357G)(E23-G377;R357G).mmH) ESLGTEQRVVGRVAEVSGPEPSQQEQLVFGSGDAVELSCPPPGGGPMGPTVWVKDGAGLVPSERVLVGPQRLQVLNASHEDSGAYSCRQRLTQLVLCHFSVRVTDAPSSGDDEDGEDEAEDTGVDTGAPYWTRPERMDKKLLAVPAANTVRFRCPAAGNPTPSISWLKNGKEFRGEHRIGGIKLRHQQWSLVMESVVPSDRGNYTCVVENKFGSIRQTYTLDVLERSPHRPILQAGLPANQTAVLGSDVEFHCKVYSDAQPHIQWLKHVEVNGSKVGPDGTPYVTVLKSWISESVEADVRLRLANVSERDGGEYLCRATNFIGVAEKAFWLSVHGPRAAEEELVEADEAGSVYAGEQKLISEEDLGGEQKLISEEDLHHHHHH (SEQ ID NO: 242) [Table 1-1] *V as described in WO2016 / 134234 H and V L Please refer to. REGN6331 heavy chain EVQLVESGGGLVQPGGSLRLSCAASGFTFTSTGISWVRQAPGKGLEWVGRIYPTSGSTNYADSVKGRFTISADTSKNTAYLQMNSLRAEDTAVYYCARTYGIYDLYVDYTEYVMDY WGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKT HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 243) REGN6331 light chain DIQMTQSPSSLSASVGDRVTITCRASQDVDTSLAWYKQKPGKAPKLLIYSASFLYSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSTGHPQTFGQGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 244) [Table 1-2] *NB=Not bonded **NT = Not Tested [Table 1-3] *NA: Not Acquired. Technical problems prevented data acquisition and analysis. **NB=Non-bonded **NT: Not tested [Table 1-4] *NB=Not bonded [Table 1-5] *NA = Not Acquired. Technical issues prevented data acquisition and analysis. **NT = Not Tested

[0133] Example 2: Blocking Assay Anti-FGFR3 antibodies that block the binding of dimeric human FGFR3b or FGFR3c to human acidic or basic FGF were analyzed by ELISA. [Table 2-1-1] [Table 2-1-2]

[0134] An ELISA-based blocking assay was developed to determine the ability of anti-FGFR3 antibodies to block the binding of human fibroblast growth factor receptor 3 isoform b (hFGFR3b) or human fibroblast growth factor receptor 3 isoform c (hFGFR3c) to human acidic fibroblast growth factor (h-acidic FGF) or basic fibroblast growth factor (h-basic FGF) ligands.

[0135] The human FGFR3b recombinant protein used in the experiments had the hFGFR3b extracellular domain (amino acids E23-G377) expressed with the C-terminal Fc portion of mouse IgG2a (amino acids E98-K330) (hFGFR3b-mFc, accession number NM_001163213.1). hFGFR3c and h-acidic FGF proteins were purchased commercially. The human FGFR3c protein had the hFGFR3c extracellular domain (amino acids Glu23-Gly375) expressed with the C-terminal Fc portion of human IgG1 (amino acids Pro100-Lys330) (hFGFR3c-hFc, accession number P22607). The h-acidic FGF protein was expressed with amino acids Ala2-Asp155 (accession number P05230.1). The h-basic FGF protein was purchased commercially. It was expressed with amino acids Ala144 to Ser288 (accession number NM_002006).

[0136] For the blocking assay, 96-well microtiter plates were coated overnight at 4°C with either 2 mg / ml of hFGFR3b-mFc or hFGFR3c-hFc protein in PBS + 10 mg / ml heparin. Nonspecific binding sites were then blocked using a 0.5% (w / v) BSA + 10 mg / ml heparin solution in PBS. In other 96-well microtiter plates, fixed amounts of 4 nM hFGFR3b-mFc, 0.4 nM, or 7 nM hFGFR3c-hFc were bound for 1 hour with anti-FGFR3, anti-FGFR3 comparator, or irrelevant human IgG1 or IgG4 isotype antibodies at dilutions ranging from 3.4 pM to 200 nM in PBS + 0.5% BSA + 10 mg / ml heparin. A fixed concentration of hFGFR3b or hFGFR3c protein was determined as the concentration that produced 50% of maximal binding to plate-bound hFGFR3b or hFGFR3c protein (EC 50The antibody complexes with 4 nM hFGFR3b-mFc or 0.4 nM hFGFR3c-hFc were transferred to a microtiter plate coated with acidic FGF protein. In parallel, antibody complexes with 7 nM hFGFR3c-hFc were added to a microtiter plate coated with basic FGF protein. After 1 hour of incubation at room temperature, the plates were washed, and the plate-bound hFGFR3b-mFc or hFGFR3c-hFc proteins were detected with horseradish peroxidase (HRP)-conjugated goat anti-mouse or goat anti-human Fcγ fragment-specific antibodies. The plates were then developed using TMB substrate solution (BD Biosciences) according to the manufacturer's recommended procedure, and the absorbance at 450 nm was measured using a Victor X5 plate reader.

[0137] Binding data were analyzed using a sigmoidal (four-parameter logistic) dose-response model using GraphPad Prism software. The calculated IC was defined as the concentration of antibody required to block 50% of the binding of hFGFR3b-mFc or hFGFR3c-hFc to plate-coated h-acidic FGF or h-basic FGF protein. 50 The value was used as an index of blocking efficacy. The percent blocking of FGFR3 antibody at a given concentration was calculated based on the formula shown below.

number

[0138] Antibodies that blocked more than 50% of binding at the highest concentration tested were classified as blockers and given an IC 50 The values ​​were reported.

[0139] The ability of anti-FGFR3 antibodies to block the binding of human FGFR3b to acidic FGF protein or hFGFR3c to acidic or basic FGF protein was evaluated using a sandwich ELISA-based blocking assay. In this assay, a fixed concentration of hFGFR3b-mFc or hFGFR3c-hFc was preincubated with a wide range of anti-FGFR3 antibody concentrations and then allowed to bind to plate-immobilized acidic or basic FGF protein. Plate-bound hFGFR3b-mFc or hFGFR3c-hFc was detected with HRP-conjugated goat anti-mouse or goat anti-human Fcγ fragment-specific antibodies, respectively. Six anti-FGFR3 antibodies were evaluated for their inhibition of hFGFR3b-mFc binding to acidic FGF protein. Antibody H4H30093P2, which also binds to hFGFR3c, was further tested for inhibition of hFGFR3c-hFc binding to hAcidic FGF or hBasic FGF proteins. 50 The values ​​and maximum block at the highest tested concentration are summarized in Table 2-2.

[0140] All six anti-FGFR3 antibodies (H4H30063P, H4H30066P, H4H30071P, H4H30089P2, H4H30093P2, and H4H30102P2) showed concentration-dependent blocking of hFGFR3b-mFc binding to hFGFR3b-mFc protein, with the degree of blocking ranging from 68% to 95% at the highest antibody concentration tested (200 nM). The IC values ​​of these blocking antibodies were 50 The IC values ​​ranged from 2 nM to 15 nM. Antibody H4H30093P2 showed less than 50% blocking of hFGFR3c binding to either acidic or basic FGF at the highest antibody concentration tested and was classified as a non-blocker of hFGFR3c. The anti-FGFR3 comparator antibody blocked hFGFR3b binding to acidic FGF with an IC of 1.5 nM. 50 and blocked the binding of hFGFR3c to hacidic FGF or hbasic FGF with IC50 of 0.1 nM and 8.9 nM, respectively. 50 Human IgG1 or IgG4 isotype control antibodies did not block in either assay. [Table 2-2] Nbl: Non-blocking: Blocking is less than 50% ND: undecided (*) The anti-FGFR3-hIgG1 comparator and the hIgG1 isotype control were tested in separate experiments for blocking the binding of hFGFR3b to hacidic FGF protein or hFGFR3c to hbasic FGF protein.

[0141] Example 3: Octet cross-competition analysis of anti-FGFR3 antibodies Binding competition between anti-FGFR3 monoclonal antibodies previously determined to bind to hFGFR3b.mmH was determined using a real-time label-free biolayer interferometry (BLI) assay on an Octet HTX biosensor (ForteBio Corp., A Division of Pall Life Sciences). All experiments were performed in a buffer consisting of 0.01 M HEPES (pH 7.4), 0.15 M NaCl, 3 mM EDTA, 0.05% v / v surfactant P20, and 0.1 mg / mL BSA (Octet HBS-EP buffer) at 25°C with plate shaking at 1000 rpm. To assess whether the two antibodies could compete with each other for binding to the hFGFR3b ectodomain (hFGFR3b.mmH, REGN3152) expressed with a C-terminal myc-myc-histidine tag, approximately 0.2 nm of hFGFR3b.mmH was captured on an Octet biosensor (Fortebio Inc, #18-5079) coated with an anti-pentaHis antibody by immersing the biosensor in a well containing a 20 μg / mL solution of hFGFR3b.mmH for 23 seconds. The biosensor was then saturated with a first anti-FGFR3 monoclonal antibody (hereinafter referred to as mAb-1) by immersing it in a well containing a 50 μg / mL solution of mAb-1 for 5 minutes. The biosensor was then immersed in a well containing a 50 μg / mL solution of a second anti-FGFR3 monoclonal antibody (hereinafter referred to as mAb-2) for 3 minutes. Real-time binding responses were monitored throughout the course of the experiment, with binding responses recorded at the end of each step. The response of mAb-2 binding to hFGFR3b.mmH pre-complexed with mAb-1 was compared, and the competitive or non-competitive properties of an anti-FGFR3 monoclonal antibody relative to another antibody were determined using a 50% inhibition threshold. Table 3-1 summarizes cross-competing antibodies that competed for binding to hFGFR3b.mmH, regardless of the order of sequential binding of mAb-1 and mAb-2. [Table 3-1-1] [Table 3-1-2]

[0142] Example 4: Characterization of FGFR3 antibodies in a cell proliferation assay using engineered BaF3 cells overexpressing human FGFR3 WT or FGFR3-S249C mutant receptors. Using engineered IL-3-dependent Ba / F3 mouse hematopoietic cell lines genetically modified to stably express human fibroblast growth factor receptor 3b wild-type or mutant S249C, proliferation assays were used to evaluate the ability of anti-FGFR3 antibodies to block FGFR3 signaling.

[0143] The FGFR3 antigen-binding molecules and controls tested in this experiment are shown in Table 4-1. [Table 4-1] Cell line: BAF3 / FGFR3b (ACL11991): An IL-3-dependent murine pro-B cell line engineered to stably express full-length human FGFR3b (accession number NP_001156685.1, amino acids M1-T808). Cells are maintained in RPMI 1640 + 10% FBS + P / S / G + 1 ng / ml mouse IL-3 + 500 μg / ml neomycin at 37°C and 5% CO2. BAF3 / FGFR3b_S249C (ACL11986): An IL-3-dependent murine pro-B cell line engineered to stably express full-length human FGFR3b (accession number NP_001156685.1, amino acids M1-T808, S249C). Cells are maintained in RPMI 1640 + 10% FBS + P / S / G + 1 ng / ml mouse IL-3 + 500 μg / ml neomycin at 37°C and 5% CO2.

[0144] The FGFR3 receptor is a member of the receptor tyrosine kinase (RTK) family that regulates cell proliferation, survival, differentiation, and migration in multicellular organisms. Activation of the wild-type (WT) receptor occurs through binding of its soluble ligand, e.g., FGF1, which drives FGFR3 homodimerization and autophosphorylation, ultimately resulting in the activation of multiple intracellular signaling cascades, including the Ras / MAPK, PLCγ1 / PKC, PI3-kinase / Akt, and STAT pathways (Xie et al., FGF / FGFR signaling in health and disease, Signal Transduction and Targeted Therapy (2020) 5:181). Mutations in FGFR3 that result in aberrant FGFR3 activation are associated with many types of human malignancies. The S249C mutation results in constitutive, ligand-independent FGFR3 activation (Tomlinson et al., Knockdown by shRNA identifies S249C mutant FGFR3 as a potential therapeutic target in bladder cancer, Oncogene. 2007 August 30;26(40):5889-5899).

[0145] To study the blocking effect of anti-FGFR3b antibodies on signal transduction, we developed a proliferation assay using an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express human fibroblast growth factor receptor 3b wild-type or mutant S249C (FGFR3b - Accession Number NP_001156685.1, amino acids M1-T808) (Kong et al., Ba / F3 transformation assays, Oncotarget, 2017, Vol. 8, (No. 22), pp: 35488-35489). Engineered BaF3 / FGFR3b cells were stimulated with the ligand (human FGF1) in the presence of titrating antibodies, and cell proliferation was assessed using CellTiter-Glo, which measures ATP, a product of viable, proliferating cells.

[0146] Engineered BaF3 / hFGFR (WT or S249C) cells (RPMI1640 + 10% FBS + penicillin / streptomycin / L-glutamine + 1 ng / mL mouse IL-3 + 500 μg / mL neomycin) were washed and seeded in IL-3-free culture medium containing 5 μg / mL heparin and 1 nM human FGF1. Cells were cultured at 10 5 Cells / well were seeded into 96-well white tissue culture plates, followed by the addition of 1:4 serially diluted antibodies ranging from 1.5 pM to 100 nM (including a no-antibody control) (plotted at 0.4 pM). After antibody addition, the 96-well white microtiter plates were incubated at 37°C / 5% CO2 for 72 hours, followed by the addition of an equal volume of CellTiter-Glo™ (Promega) reagent to lyse the cells and detect luciferase activity. Emitted light was captured in relative light units (RLU) on a multilabel plate reader Envision (PerkinElmer). The EC of the antibodies was 50 Values ​​were determined from a four-parameter logistic equation for a 10-point dose-response curve (the 10th point contained no antibody) using GraphPad Prism software.

[0147] Anti-FGFR3b antibodies (H4H30063P and H4H30102P2) were tested in the presence of 1 nM FGF1 and 5 ug / ml heparin, along with a comparator antibody (REGN6331) and an isotype-matched negative control (see Table 4-2 and Figure 1).

[0148] Anti-FGFR3b antibodies (H4H30063P and H4H30102P2) and their corresponding matching isotype control (REGN1945) were tested alongside a comparator antibody (REGN6331) and an isotype-matched control (REGN1932) in the presence of 1 nM FGF1 and 5 μg / ml heparin. In experiments using the BaF3 / hFGFR3b WT cell line, antibodies H4H30063P and REGN6331 exhibited similar levels of maximal inhibition of proliferation, whereas antibody H4H30102P2 did not achieve the same level of maximal inhibition. The extent of ligand-mediated proliferation in BaF3 / FGFR3_S249C cells was minimal due to the S249C mutation, which results in constitutive FGFR3b activity. Nevertheless, addition of the ligand resulted in a slight enhancement of proliferation, which could be inhibited to similar maximal levels by antibodies H4H30063P and REGN6331, whereas H4H30102P2 produced minimal inhibition, with IC 50 The value was not calculable. [Table 4-2] a Maximum block is given as the mean maximum block detected within the dose range tested. Abbreviations: ND: Not determined, NC: Not calculated, potency value could not be determined by PRISM

number

[0149] Example 5: Characterization of the mechanism of action of FGFR3 antibodies Assays were performed to evaluate: (1) inhibition of FGFR3 S249C dimerization using the bladder cancer cell line UMUC14, which harbors the endogenous FGFR3 S249C mutation, and (2) inhibition of FGF1 / heparin-induced downstream signaling in BaF3 cells expressing wild-type FGFR3. Cell line: ● UMUC14 (Sigma-Aldrich): Cells are maintained in MEM + 1% non-essential amino acids (NEAA) 10% FBS + P / S at 37°C and 5% CO2. BAF3 / FGFR3b (ACL11991): An IL-3-dependent murine pro-B cell line engineered to stably express full-length human FGFR3b (accession number NP_001156685.1, amino acids M1-T808). Cells are maintained in RPMI 1640 + 10% FBS + P / S / G + 1 ng / ml mouse IL-3 + 500 μg / ml neomycin at 37°C and 5% CO2. reagent: rh acidic FGF (R&D Systems, catalog 232-FA), reconstituted at 100 mg / ml in PBS / 0.1% BSA Porcine intestinal mucosa-derived heparin sodium salt (Sigma Aldrich, catalog H3393-100KU), reconstituted at 50 mg / ml in H2O FGFR3 (B-9) (Santa Cruz Biotechnology, catalog sc-13121) ECL anti-mouse IgG horseradish peroxidase-conjugated whole antibody (sheep origin) (GPR, catalog NXA934V) SuperSignal West Pico PLUS Chemiluminescent Substrate (Thermo Scientific, catalog 34578) ●Cell lysis buffer (10x) (Cell Signaling Technology, Catalog 9803) Phospho-p44 / 42 MAPK (Erk1 / 2) (Cell Signaling Technology, Cat. 4370) p44 / 42 MAPK (Erk1 / 2) (Cell Signaling Technology, Catalog 4695) Goat anti-rabbit IgG (H+L), HRP-conjugated antibody (Seracare, catalog number 5450-0010)

[0150] For receptor dimerization assays, UMUC14 bladder cancer cells were seeded in 6-well tissue culture plates (Corning) in complete medium (MEM medium containing 10% FBS, 1% non-essential amino acids, and Pen / Strep) and cultured overnight at 37°C and 5% CO2. Cells were then serum-starved overnight in starvation medium (MEM medium containing 0.5% FBS and Pen / Strep) and subsequently treated with antibodies at the indicated doses for 3 hours. Cells were washed with pre-chilled PBS and collected in lysis buffer containing protease inhibitors. Equal amounts of cell lysates were analyzed by either reducing or non-reducing SDS-PAGE. Blots were blocked with 0.5% Tween® 20 in Tris-buffered saline (TBS) containing 5% nonfat dry milk, followed by overnight incubation with anti-FGFR3 primary antibody (Santa Cruz). The membranes were washed three times with TBST and incubated with secondary antibodies, then developed with SuperSignal West Pico or Femto substrate, and luminescence images were captured with a C300 imager (Azure Biosystems).

[0151] To test the effect of anti-FGFR3 antibodies on ligand-induced signaling, we used an engineered IL-3-dependent Ba / F3 mouse hematopoietic cell line genetically modified to stably express wild-type human fibroblast growth factor receptor 3b. Engineered BaF3 / FGFR3b cells were incubated overnight in starvation medium (RPMI1640 + penicillin / streptomycin / L-glutamine + 1 ng / mL mouse IL-3). After starvation, cells were either untreated or pretreated with 100 nM antibody for 3 hours, followed by stimulation with ligand (100 ng / mL human FGF1 and 10 mg / mL heparin) for 10 minutes at 37°C. See Figure 3. Cells were lysed in lysis buffer, and equal amounts of cell lysates were analyzed by SDS-PAGE. Blots were incubated overnight with pMAPK or MAPK antibodies, followed by incubation with an anti-rabbit HRP secondary antibody. Membranes were developed with SuperSignal West Pico or Femto substrate, and luminescence images were captured using a C300 imager (Azure Biosystems).

[0152] Antibody H4H30063P demonstrated dose-dependent inhibition of FGFR3 S249C dimerization and stronger inhibition of receptor dimerization than the comparator antibody REGN6331 (see Figure 2). In addition, H4H30063P reduced FGF1 / Hep stimulation-dependent phosphorylation of MAPK (see Figure 3).

[0153] Example 6: Characterization of FGFR3 antibodies in a cancer cell spheroid proliferation assay using the bladder cancer cell line UMUC14, which harbors the endogenous FGFR3 S249C mutation. Anti-FGFR3 antibody-mediated inhibition of cancer cell proliferation was evaluated. cell line ● UMUC14 (Sigma-Aldrich): Cells are maintained in MEM + 1% non-essential amino acids (NEAA) 10% FBS + P / S at 37°C and 5% CO2. reagent Corning spheroid 96-well microplate (Corning, Catalog No. 4520) CellTiter-Glo3D Cell Viability Assay (Promega, Catalog No. G9682)

[0154] 7,500 UMUC14 bladder cancer cells were seeded into U-bottom low-attachment 96-well spheroid plates (Corning) in culture medium (MEM medium containing 10% FBS, 1% non-essential amino acids, and Pen / Strep). Cells were cultured at 37°C and 5% CO2 for 48 hours to allow tumor spheroid formation. Tumor spheroids were treated with antibodies at concentrations ranging from 100 nM to 15.2 pM in a 1:3 serial dilution, as indicated. Cells were cultured for 5–6 days and then subjected to the CellTiter-Glo3D Viability Assay (Promega) according to the manufacturer's protocol. Luminescence signals were read using a SpectraMax M3 plate reader. Cell proliferation was expressed as a percentage of untreated controls. Data were analyzed using GraphPad Prism software with a three-parameter nonlinear curve fit.

[0155] H4H30063P exhibited more potent growth inhibition than antibody H4H30071P and comparator antibody REGN6331. See Figure 4.

[0156] Example 7: In vivo characterization of FGFR3 antibodies in a tumor growth inhibition assay using a xenograft model of the bladder cancer cell line UMUC14, which harbors the endogenous FGFR3 S249C mutation. In this example, inhibition of growth of bladder cancer cell lines in a mouse xenograft model exposed to anti-FGFR3 antibodies was evaluated. cell line ● UMUC14 (Sigma-Aldrich): Cells are maintained in MEM + 1% non-essential amino acids (NEAA) 10% FBS + P / S at 37°C and 5% CO2. reagent Matrigel Basement Membrane Matrix (Corning, Catalog No. 354234, Lot: 8085009)

[0157] Tumor cells (5 × 10 in 50% Matrigel 6 100 μl of UMUC14 cells were subcutaneously implanted into the right flank of 6- to 8-week-old female SCID mice (Jackson Laboratory). Once tumors were established (approximately 200 mm in volume), 3 ), mice were randomized into treatment groups (n=10 mice per group) and injected intraperitoneally twice weekly with 3 or 10 mg / kg of anti-FGFR3 antibody or isotype control. Tumor volume was calculated in mm using the following formula: 3 Expressed as: V = 0.5 × a × b 2 (where a and b were the long and short diameters of the tumor, respectively.) All data were analyzed using GraphPad Prism, and tumor sizes were graphed as mean ± SEM.

[0158] H4H30063P demonstrated stronger tumor growth inhibition than the comparator antibody REGN6331 in the UMUC14 xenograft model, which endogenously expresses the FGFR3 S249C mutation. See Figure 5.

[0159] Example 8: Effect of FGFR3 oncogenic signaling on CD73 expression. The effects of FGFR3 mutations and FGFR3 inhibitors on CD73 expression were evaluated. Cell line: UMUC14 (Sigma-Aldrich): Cells are maintained in MEM + 1% non-essential amino acids (NEAA) 10% FBS + P / S at 37°C and 5% CO2. Fadu EV and S249C cells are maintained in MEM + 10% FBS + Pen / Strep + 400ug / ml neomycin at 37°C and 5% CO2. reagent: FGFR-3 (B-9) (Santa Cruz Biotechnology, catalog number sc-13121) NTSE / CD73 (D7F9A) rabbit mAb (Cell Signaling Technology, Catalog No. 13160) Goat anti-rabbit IgG (H+L), HRP conjugate (Seracare, catalog number 5450-0010) Peroxidase anti-mouse IgG (H+L) (Vector Laboratories, Catalog No. PI-2000) SuperSignal West Pico PLUS Chemiluminescent Substrate (Thermo Scientific, Catalog No. 34578) SuperSignal West Femto Maximum Substrate (Thermo Scientific, Catalog No. 34096) ●Cell lysis buffer (10x) (Cell Signaling Technology, Catalog No. 9803) RIPA buffer (Sigma Aldrich, Catalog No. R0278) Matrigel (Corning, catalog number 354234)

[0160] To examine the effects of anti-FGFR3 antibody or tyrosine kinase inhibitor (AZD4547; commercially available) on CD73 expression, UMUC14 bladder cancer cells were seeded in 6-well tissue culture plates (Corning) in complete medium (MEM medium containing 10% FBS, 1% non-essential amino acids, and Pen / Strep) and cultured overnight at 37°C and 5% CO2. Cells were then treated with the indicated concentrations (100 nM, 10 nM, or 1 nM) of antibody or inhibitor for 48 hours. Cells were washed with pre-chilled PBS and harvested in lysis buffer containing protease and phosphatase inhibitors. Equal amounts of cell lysates were analyzed by SDS-PAGE. Blots were blocked with 0.5% Tween® 20 in Tris-buffered saline (TBS) containing 5% nonfat dry milk, followed by overnight incubation with anti-CD73 primary antibody (Cell Signaling Technology). The membranes were washed three times with TBST and incubated with secondary antibodies, then developed with SuperSignal West Pico or Femto substrate, and luminescence images were captured with a C300 imager (Azure Biosystems).

[0161] To test the effect of FGFR3 oncogenic signaling on CD73 expression in vivo, 3 × 10 cells expressing FGFR3 oncogenic mutations (S249C or FGFR3-TACC3) or empty vector control (EV) were cultured in vitro. 6 Fadu cells were implanted subcutaneously into the right flank of 6- to 8-week-old female SCID mice (Jackson Laboratory). Approximately 16 days after implantation, tumors were harvested, flash-frozen, and lysed in RIPA buffer. Equal amounts of tumor lysates were analyzed by SDS-PAGE and blotted with anti-CD73 and anti-FGFR3 antibodies, as described above.

[0162] To test the effect of anti-FGFR3 inhibitory antibody or tyrosine kinase inhibitor (AZD4547) on CD73 expression in vivo, tumor cells (5 × 10 in 50% Matrigel) were cultured in 100% PBS. 6 UMUC14, 3 x 10 6Fadu EV, or S249C) were subcutaneously implanted into the right flank of 6- to 8-week-old female SCID mice (Jackson Laboratory). Once tumors were established (approximately 200 mm in volume), 3 Mice were randomized into treatment groups (n = 5–6 mice per group) and received a single intraperitoneal injection of anti-FGFR3 antibody (15 mg / kg) or isotype control. The tyrosine kinase inhibitor AZD4547 (25 mg / kg) was administered by oral gavage once daily for 3 days. Tumors were harvested 4 days after the start of treatment. Tumors were harvested, snap-frozen, and lysed in RIPA buffer. Equal amounts of tumor lysates were analyzed by SDS-PAGE and blotted with anti-CD73 and anti-FGFR3 antibodies as described above. Membranes were developed with SuperSignal West Pico or Femto substrate, and luminescence images were captured using a C300 imager (Azure Biosystems). The intensity of each CD73 and actin band was quantified using Image J (NIH), and the CD73 / actin ratio for each sample was graphed using Prism Graphpad.

[0163] Downregulation of CD73 protein levels in response to FGFR3 inhibition in UMUC14 cells in vitro. As shown in Figure 6, both the anti-FGFR3 inhibitor antibody and the pan-FGFR tyrosine kinase inhibitor (AZD4547) demonstrated dose-dependent downregulation of CD73 expression. As the molar concentration of each agent increased from 1 nM to 100 nM, the CD73 band intensity on the blot decreased.

[0164] Downregulation of CD73 protein levels in response to FGFR3 inhibition in UMUC14 cells in vivo. In the blot, CD73 band intensity decreased with increasing anti-FGFR3 antibody concentration. See Figure 7. The CD73 / actin band intensity is summarized graphically in Figure 8.

[0165] FGFR3 activation is sufficient to induce CD73 expression. As shown in the blots in Figure 9, cells expressing a constitutively active FGFR3 mutant, without ligand-induced activation, showed increased expression of CD73 relative to control and wild-type FGFR3 in vitro.

[0166] Upregulation of CD73 expression in Fadu tumors engineered to express the FGFR3 S249C mutant or FGFR3-TACC3 fusion. Expression of CD73 in Fadu tumors expressing empty vector (EV; Figure 10(A)) showed little or no activation of CD73 expression, whereas tumors expressing the S249C (Figure 10(B)) or FGFR-TACC3 (Figure 10(C)) FGFR3 mutants showed increased expression of CD73.

[0167] Downregulation of CD73 protein levels in response to FGFR3 inhibition in Fadu S249C tumors in vivo. Mice bearing FADU tumors expressing the FGFR3 S249C mutant and treated with a single intraperitoneal injection of FGFR3 mAb (15 mg / kg) or daily administration of AZD4547 (25 mg / kg) showed reduced CD73 expression compared to control-treated mice. The CD73 band intensity in the blot shown in Figure 11(A) is quantified in the graph in Figure 11(B).

[0168] Example 9: Antibody inhibition of proliferation of BaF3 cells expressing TKI resistance mutations. The IL-3-dependent murine pro-B cell line BaF3 cells were engineered to stably express full-length human FGFR3b S249C, V557L, V557M, S249C / V557L, and S249C / V557M (accession number NP_001156685.1 for WT FGFR3b, amino acids M1 to T808). Cells were maintained in RPMI 1640 + 10% FBS + P / S / G + 1 ng / ml mouse IL-3 + 500 μg / ml neomycin at 37°C and 5% CO2. For proliferation assays, cells were washed with IL-3-free culture medium and cultured for 10 min. 5Cells were seeded at 10 ...

[0169] Acquired resistance to FGFR TKIs has been reported and is frequently associated with secondary mutations in the kinase domain (Facchinetti F et al. AACR 2023, abstract 3458; Chell V et al. Oncogene 2013). One of the resistance mutation hotspots that appears to drive disease progression is the gatekeeper mutation V555M / L. To test the efficacy of FGFR3 antibodies in the context of TKI resistance mutations, we generated BaF3 cell lines expressing FGFR3 S249C with or without the gatekeeper mutations V557M or V557L. The pan-FGFR TKIs AZD4547 and erdafitinib potently inhibited the proliferation of BaF3 cells expressing FGFR3 S249C (IC50 9.9 nM and 1.2 nM, respectively), but were ineffective in cells expressing FGFR3 containing only the V557M / L mutation or both the S249C and V557M / L mutations. In contrast, the FGFR3 antibody H4H30063P was able to strongly inhibit the proliferation of BaF3 cells expressing double mutant FGFR3 (S249C + V557M or L). The IC50 values ​​of H4H30063P for S249C, S249C / V557M, and S249C / V557L were 1.36 nM, 3.9 nM, and 4.3 nM, respectively. See Figure 12.

[0170] Example 10: Hydrogen / Deuterium Exchange (HDX) Epitope Mapping. HDX experiments were performed using a customized HDX automation system (NovaBioAssays, MA) connected to a Q Exactive HF mass analyzer (Thermo Fisher Scientific, MA). Figure 21 shows an exemplary HDX-mass spectrometry experimental process.

[0171] To initiate deuterium exchange, 10 μL of protein sample (hFGFR3b.mmh alone or hFGFR3b.mmh mixed with H4H30117P2, H4H30063P, H4H30045P, or H4H30108P2 at a 2:1 ratio) was diluted with 90 μL of PBS-D2O buffer (10 mM, pH 7.4 at 25 °C). After 5 or 10 min, deuterium exchange was quenched by adding 100 μL of quenching buffer (0.5 M TCEP, 4 M guanidine hydrochloride, pH 2.08), followed by incubation at 20 °C for 90 s. The quenched sample was digested with an online pepsin / protease XIII column (NovaBioAssays, MA) at room temperature using 0.1% formic acid in water at 100 μL / min. Digestive peptides were captured on an ACQUITY UPLC Peptide BEH C18 VanGuard Pre-column (2.0 × 5 mm, Waters, MA) and further separated on an ACQUITY UPLC Peptide BEH C18 column (2.0 × 50 mm, Waters, MA) using a 15-minute gradient of 0.1% formic acid in water and 0.1% formic acid in acetonitrile at −5°C at 200 μL / min. Eluted peptides were analyzed by LC-MS / MS or LC-MS mode on a Q Exactive HF mass spectrometer.

[0172] The deuterium incorporation percentage (D%) of each peptide was calculated. The difference in deuterium incorporation was calculated as ΔD% = D% of hFGFR3b-antibody - D% of hFGFR3b. Differences of |ΔD| > 5% (average from two replicates) were considered significant. Mass spectra of peptides showing significant differences were manually confirmed.

[0173] The results of HDX epitope mapping for the anti-FGFR3b antibodies H4H30117P2 and H4H30063P are shown in Figure 13. The results of HDX epitope mapping for the anti-FGFR3b antibodies H4H30045P and H4H30108P2 are shown in Figure 14. HDX protection of FGFR3 by the anti-FGFR3b antibodies H4H30063P Fab and H4H30117P2 scFv is shown in Figure 15. HDX epitope mapping of FGFR3 antibodies is shown in Figure 16 (A-B). As shown in the structure, the epitope comprises a segment of the peptide, forming a continuous surface patch for interaction. The epitope is likely a conformational epitope.

[0174] The results of HDX epitope mapping for H4H30063P are shown in Figure 17. The results of HDX epitope mapping for H4H30108P2 are shown in Figure 18. The results of HDX epitope mapping for H4H30117P2 are shown in Figure 19. The results of HDX epitope mapping for H4H30045P are shown in Figure 20.

[0175] All references cited herein are incorporated by reference to the same extent as if each individual publication, data entry (e.g., GenBank sequence or GeneID entry), patent application, or patent were specifically and individually indicated to be incorporated by reference. This incorporation-by-reference statement is intended by the applicant to relate to any and all individual publications, database entries (e.g., GenBank sequence or GeneID entry), patent applications, or patents, each of which is clearly identified, even if such citation is not immediately adjacent to the dedicated incorporation-by-reference statement. If a dedicated incorporation-by-reference statement exists, its inclusion within this specification does not in any way weaken this general statement of incorporation-by-reference. The citation of a reference herein is not intended as an admission that the reference is relevant prior art, and does not constitute any admission regarding the content or date of these publications or documents.

Claims

1. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, comprising: a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 2, 22, 42, 62, 82, 102, 122, 140, 159, 169, 179, 199, or 219; and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 10, 30, 50, 70, 90, 110, 130, 148, 187, 207, or 227.

2. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, (a) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 2, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 10; (b) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 22, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 30; (c) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 42, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 50; (d) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 62, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 70; (e) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 82, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 90; (f) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 102, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 110; (g) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 122, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 130; (h) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 140, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (i) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 159, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (j) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 169, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 148; (k) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 179, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 187; (l) a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 199, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO: 207; and / or (m) An isolated antibody or antigen-binding fragment thereof, comprising a heavy chain variable region (HCVR) comprising HCDR1, HCDR2, and HCDR3 of HCVR comprising the amino acid sequence set forth in SEQ ID NO: 219, and a light chain variable region (LCVR) comprising LCDR1, LCDR2, and LCDR3 of LCVR comprising the amino acid sequence set forth in SEQ ID NO:

227.

3. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, (a) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 4, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 6, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 8; and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 12, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 16; (b) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 24, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 26, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 28, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 32, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 36; (c) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 44, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 46, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 48, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 52, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 54, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 56; (d) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 64, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 66, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 68, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 72, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 74, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 76; (e) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 84, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 86, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 88; and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 92, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 94, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 96; (f) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 104, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 106, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 108, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 112, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 114, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 116; (g) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 124, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 126, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 128, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 132, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 134; (h) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 142, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 144, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 146, and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 153; (i) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 161, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 163, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 165; and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 153; (j) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 171, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 173, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 175; and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 150, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 14, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 153; (k) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 181, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 183, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 185; and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 189, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 191, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 193; (l) a heavy chain variable region comprising an HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 201, an HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 203, and an HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 205; and a light chain variable region comprising an LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 209, an LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 211, and an LCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 213; and / or (m) An isolated antibody or antigen-binding fragment thereof, comprising: a heavy chain variable region comprising HCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 221, HCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 223, and HCDR3 comprising the amino acid sequence set forth in SEQ ID NO: 225; and a light chain variable region comprising LCDR1 comprising the amino acid sequence set forth in SEQ ID NO: 32, LCDR2 comprising the amino acid sequence set forth in SEQ ID NO: 34, and LCDR3 comprising the amino acid sequence set forth in SEQ ID NO:

76.

4. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 2, 22, 42, 62, 82, 102, 122, 140, 159, 169, 179, 199, or 219, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 10, 30, 50, 70, 90, 110, 130, 148, 187, 207, or 227.

5. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, (a) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 2, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 10; (b) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 22, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 30; (c) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 42, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 50; (d) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 62, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 70; (e) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 82, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 90; (f) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 102, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 110; (g) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 122, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 130; (h) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 140, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 148; (i) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 159, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 148; (j) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 169, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 148; (k) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 179, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 187; (l) a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 199, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 207; and / or (m) An isolated antibody or antigen-binding fragment thereof, comprising a heavy chain variable region comprising the amino acid sequence set forth in SEQ ID NO: 219, and a light chain variable region comprising the amino acid sequence set forth in SEQ ID NO:

227.

6. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, comprising: (a) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 18, 38, 58, 78, 98, 118, 136, 155, 167, 177, 195, 215, or 229, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20, 40, 60, 80, 100, 120, 138, 157, 197, 217, or 231.

7. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, (a) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 18, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 20; (b) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 38, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 40; (c) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 58, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 60; (d) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 78, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 80; (e) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 98, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 100; (f) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 118, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 120; (g) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 136, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 138; (h) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 155, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 157; (i) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 167, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 157; (j) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 177, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 157; (k) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 195, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 197; (l) a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 215, and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 217; and / or (m) An isolated antibody or antigen-binding fragment thereof, comprising a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 229, and a light chain comprising the amino acid sequence set forth in SEQ ID NO:

231.

8. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment binds to the same epitope of FGFR3 as the antibody or antigen-binding fragment of any one of claims 1 to 7 or competes for binding to FGFR3.

9. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment thereof comprises: a. an epitope comprising the sequence GPTVWVK (SEQ ID NO: 260), and / or an epitope comprising the sequence TQR; b. an epitope comprising the sequence ADVR (SEQ ID NO: 258) and / or an epitope comprising the sequence IGVAEK (SEQ ID NO: 259); c. an epitope comprising the sequence HCKVY (SEQ ID NO: 261), and / or an epitope comprising the sequence KSWISE (SEQ ID NO: 262), and / or an epitope comprising the sequence ADVR (SEQ ID NO: 258); d. an epitope contained within or overlapping with the sequence GPTVWVK (SEQ ID NO: 260) and / or an epitope contained within or overlapping with the sequence TQR; e. an epitope contained within or overlapping with the sequence ADVR (SEQ ID NO: 258), and / or an epitope contained within or overlapping with the sequence IGVAEK (SEQ ID NO: 259), and f. An isolated antibody or antigen-binding fragment thereof that binds to one or more epitopes of FGFR3 selected from an epitope contained within or overlapping with the sequence HCKVY (SEQ ID NO:261), and / or an epitope contained within or overlapping with the sequence KSWISE (SEQ ID NO:262), and / or an epitope contained within or overlapping with the sequence ADVR (SEQ ID NO:258).

10. the antibody or antigen-binding fragment thereof a. an epitope consisting of the sequence GPTVWVK (SEQ ID NO: 260), and / or an epitope consisting of the sequence TQR; b. an epitope consisting of the sequence ADVR (SEQ ID NO: 258), and / or an epitope consisting of the sequence IGVAEK (SEQ ID NO: 259), and c) The antibody or antigen-binding fragment of claim 9, which binds to one or more epitopes of FGFR3 selected from the epitope consisting of the sequence HCKVY (SEQ ID NO: 261), and / or the epitope consisting of the sequence KSWISE (SEQ ID NO: 262), and / or the epitope consisting of the sequence ADVR (SEQ ID NO: 258).

11. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment thereof comprises: a. an epitope comprising the sequence SCPPPGGGPMGPTVWVKDGTGLVPSER (SEQ ID NO: 245), and / or an epitope comprising the sequence YSCRQRLTQRVL (SEQ ID NO: 246); b. an epitope comprising the sequence LLAVPAAN (SEQ ID NO: 247), and / or an epitope comprising the sequence VLERSPHRPILQAG (SEQ ID NO: 248), and / or an epitope comprising the sequence YVTVLKSWISE (SEQ ID NO: 249), and / or an epitope comprising the sequence ADVRLR (SEQ ID NO: 250), and / or an epitope comprising the sequence LCRATNFIGVAEKAFW (SEQ ID NO: 251); c. an epitope comprising the sequence GQQEQLVFGSGDAVE (SEQ ID NO: 252) and / or an epitope comprising the sequence VLVGPQRL (SEQ ID NO: 253); d. an epitope comprising the sequence VLERSPHRPILQAG (SEQ ID NO: 254), and / or an epitope comprising the sequence HCKVYSDAQP (SEQ ID NO: 255), and / or an epitope comprising the sequence YVTVLKSWISESVEADVRLR (SEQ ID NO: 256), and / or an epitope comprising the sequence LCRATNFIGVAEKAF (SEQ ID NO: 257); e. an epitope contained within or overlapping with the sequence SCPPPGGGPMGPTVWVKDGTGLVPSER (SEQ ID NO: 245) and / or an epitope contained within or overlapping with the sequence YSCRQRLTQRVL (SEQ ID NO: 246); f. an epitope contained within or overlapping with the sequence LLAVPAAN (SEQ ID NO:247), and / or an epitope contained within or overlapping with the sequence VLERSPHRPILQAG (SEQ ID NO:248), and / or an epitope contained within or overlapping with the sequence YVTVLKSWISE (SEQ ID NO:249), and / or an epitope contained within or overlapping with the sequence ADVRLR (SEQ ID NO:250), and / or an epitope contained within or overlapping with the sequence LCRATNFIGVAEKAFW (SEQ ID NO:251); g. an epitope contained within or overlapping with the sequence GQQEQLVFGSGDAVE (SEQ ID NO: 252), and / or an epitope contained within or overlapping with the sequence VLVGPQRL (SEQ ID NO: 253), and h. An isolated antibody or antigen-binding fragment thereof that binds to one or more epitopes of FGFR3 selected from an epitope contained within or overlapping with the sequence VLERSPHRPILQAG (SEQ ID NO:254), and / or an epitope contained within or overlapping with the sequence HCKVYSDAQP (SEQ ID NO:255), and / or an epitope contained within or overlapping with the sequence YVTVLKSWISESVEADVRLR (SEQ ID NO:256), and / or an epitope contained within or overlapping with the sequence LCRATNFIGVAEKAF (SEQ ID NO:257).

12. the antibody or antigen-binding fragment thereof a. an epitope consisting of the sequence SCPPPGGGPMGPTVWVKDGTGLVPSER (SEQ ID NO: 245), and / or an epitope consisting of the sequence YSCRQRLTQRVL (SEQ ID NO: 246); b. an epitope consisting of the sequence LLAVPAAN (SEQ ID NO: 247), and / or an epitope consisting of the sequence VLERSPHRPILQAG (SEQ ID NO: 248), and / or an epitope consisting of the sequence YVTVLKSWISE (SEQ ID NO: 249), and / or an epitope consisting of the sequence ADVRLR (SEQ ID NO: 250), and / or an epitope consisting of the sequence LCRATNFIGVAEKAFW (SEQ ID NO: 251); c. an epitope consisting of the sequence GQQEQLVFGSGDAVE (SEQ ID NO: 252), and / or an epitope consisting of the sequence VLVGPQRL (SEQ ID NO: 253), and d. The antibody or antigen-binding fragment of claim 11, which binds to one or more epitopes of FGFR3 selected from the epitope consisting of the sequence VLERSPHRPILQAG (SEQ ID NO: 254), and / or the epitope consisting of the sequence HCKVYSDAQP (SEQ ID NO: 255), and / or the epitope consisting of the sequence YVTVLKSWISESVEADVRLR (SEQ ID NO: 256), and / or the epitope consisting of the sequence LCRATNFIGVAEKAF (SEQ ID NO: 257).

13. The antibody or antigen-binding fragment of any one of claims 1 to 12, wherein the FGFR3 is a monomeric or dimeric FGFR3b.

14. An isolated antibody or antigen-binding fragment thereof that specifically binds to FGFR3 or an antigen-binding fragment thereof, Affinity (K) of approximately 16 nM or greater at 25°C in a surface plasmon resonance assay Ｄ ) and myc-myc-His at the C-terminus ６ binds to monomeric human FGFR3b tagged with Affinity (K) of approximately 20 nM or greater at 25°C in a surface plasmon resonance assay Ｄ ) and myc-myc-His at the C-terminus ６ binds to monomeric cynomolgus monkey FGFR3b tagged with Affinity (K) of approximately 70 nM or greater at 25°C in a surface plasmon resonance assay Ｄ ) and myc-myc-His at the C-terminus ６ binds to monomeric mouse FGFR3b tagged with Surface plasmon resonance assay showed that the C-terminal myc-myc-His ６ does not significantly bind to tagged monomeric human FGFR3c; binds to dimeric human FGFR3b tagged with a C-terminus mouse Fc with an affinity of about 0.6 nM or greater at 25°C in a surface plasmon resonance assay; - 200 nM of the antibody blocks the binding of acidic FGF1 to human FGFR3b-mFc by approximately 68% or more. K binding to monomeric or dimeric human FGFR3b at 25°C in a surface plasmon resonance assay Ｄ K within about 0.1 nM of Ｄ and binds to monomeric cynomolgus monkey and monomeric mouse FGFR3b. IC at a concentration of approximately 15 nM or less ５０ blocks the binding of 4 nM human FGFR3b-mFc to human acidic FGF1 protein; IC at a concentration of approximately 18 nM or less ５０ blocks intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express wild-type or S249C mutant human fibroblast growth factor receptor 3b stimulated with about 5 micrograms / ml of human heparin and about 1 nM of human FGF1 ligand, A lower IC than that of blocking intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express wild-type human fibroblast growth factor receptor 3b stimulated with approximately 1 nM human FGF1 ligand and approximately 5 micrograms / ml human heparin. ５０ blocks intracellular signaling in an engineered IL-3-dependent Ba / F3 murine hematopoietic cell line genetically modified to stably express S249C mutant human fibroblast growth factor receptor 3b stimulated with about 5 micrograms / ml of human heparin and about 1 nM of human FGF1 ligand, blocks dimerization of FGFR3 or the S249C mutant with stronger inhibition than REGN6331 as measured by non-reducing SDS-PAGE assay; reducing tumor size of bladder cancer tumors expressing FGFR3 or its S249C mutant in a subject administered the antibody or fragment; - reducing the expression of CD73 in bladder cancer tumors that express FGFR3 or its S249C mutant in a subject to which the antibody or fragment has been administered; Inhibits FGF1 / heparin stimulation-induced phosphorylation of MAPK in BaF3 cells expressing wild-type FGFR3 or its S249C mutant; - inhibits the growth of UMUC14 bladder cancer cells expressing endogenous FGFR3 or its S249C mutant in a cancer cell spheroid proliferation assay; - inhibits tumor growth of bladder cancer cell line UMUC14 expressing FGFR3 or its S249C mutant in a SCID mouse xenograft model; inhibits CD73-dependent adenosine-mediated inhibition of immune cell activation; The CD8 / CD4 ratio and / or CD8+ / T in tumor tissues with tumor cells expressing FGFR3 or its S249C mutant ｒｅｇ Increasing the ratio of inhibiting FGF3-mediated activation of CD73 expression and / or adenosine production on tumor cells expressing FGFR3 or its S249C mutant, inhibiting FGFR3-dependent adenosine-mediated immune cell suppression, or - Inhibiting the proliferation of BaF3 cells expressing FGFR3 double mutants (S249C and V557M or S249C and V557L).

15. A complex comprising the antibody or antigen-binding fragment thereof according to any one of claims 1 to 14 bound to FGFR3 or an antigen-binding fragment thereof.

16. A pharmaceutical formulation comprising the antibody or antigen-binding fragment thereof according to any one of claims 1 to 14 and a pharmaceutically acceptable carrier.

17. SEQ ID NOs: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 13 1. An isolated polypeptide comprising an amino acid sequence selected from:

18. 18. An isolated polynucleotide encoding any one or more of the polypeptides of claim 17.

19. SEQ ID NOs: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141 19. The polynucleotide of claim 18, comprising a nucleotide sequence selected from the nucleotide sequences set forth in

20. A vector comprising the polynucleotide of claim 18 or 19.

21. A host cell comprising the polynucleotide of claim 18 or 19.

22. 15. A method for producing the antibody or antigen-binding fragment of any one of claims 1 to 14, comprising introducing a polynucleotide encoding a chain of the antibody or antigen-binding fragment into a host cell, incubating the host cell containing the polynucleotide in a culture medium under conditions favorable for expression of the chain, and optionally isolating the antibody or antigen-binding fragment from the host cell and / or culture medium.

23. 15. A method for administering the antibody or antigen-binding fragment of any one of claims 1 to 14 to a subject, the method comprising introducing the antibody or antigen-binding fragment into the body of the subject.

24. 24. The method of claim 23, wherein the antibody or antigen-binding fragment is introduced into the body by injection.

25. 25. The method of claim 24, wherein the injection is intramuscular, intravenous, or subcutaneous.

26. 15. A method for treating or preventing an FGFR3-mediated condition in a subject in need thereof, comprising administering to the subject a therapeutically effective amount of the antibody or antigen-binding fragment of any one of claims 1 to 14.

27. 27. The method of claim 26, wherein the FGFR3-mediated condition is cancer, bladder cancer, brain cancer, breast cancer, cervical cancer, colon cancer, endometrial cancer, gastric cancer, head and neck cancer, kidney cancer, lung cancer, multiple myeloma, ovarian cancer, pancreatic cancer, urothelial cancer, achondroplasia, Crouzon syndrome with acanthosis nigricans, epidermal nevus, hypochondroplasia, lacrimal-ear-tooth-digital (LADD) syndrome, Muenke syndrome, severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN), and / or thanatophoric dysplasia.

28. The method of any one of claims 23 to 27, wherein the subject is administered a further therapeutic agent.

29. the additional therapeutic agent is an FGFR inhibitor, erdafitinib, pemigatinib, infigratinib, rogaratinib, dexamethasone, an alkylating agent, altretamine, trabectedin, or busulfan, a nitrosourea, carmustine, lomustine, a cytotoxic antibiotic, an anthracycline, doxorubicin, valrubicin, bleomycin, or dactinomycin, an antimetabolite, methotrexate, floxuridine, clofarabine, pralatrexate, a vinca alkaloid, or vinblastine , vinorelbine, vincristine, vindesine, photodynamic drugs, porfimer sodium, aminolevulinic acid, platinum drugs, cisplatin, phenanthriplatin, taxanes, paclitaxel, docetaxel, topoisomerase inhibitors, irinotecan, topotecan, etoposide, teniposide, ziv-aflibercept, anti-cancer antibodies, rituximab, trastuzumab, cetuximab, cemiplimab, pembrolizumab, panitumumab, and bevacizumab.

30. In subjects requiring - reducing metastasis of tumor cells expressing FGFR3; - reducing the concentration of adenosine in tumors expressing FGFR3; - reducing CD73-dependent catalysis of AMP to adenosine by FGFR3-expressing tumors; - inhibiting adenosine-mediated suppression of T cell function in FGFR3-expressing tumors; 15. A method for performing a method for treating a patient comprising administering to said subject a therapeutically effective amount of the antibody or antigen-binding fragment of any one of claims 1 to 14.

31. 31. The method of claim 30, wherein the metastasis is CD73-dependent or adenosine-dependent.

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