FGFR3-iiib-binding antibodies

Abstract

Provided and exemplified herein are antibodies and antibody fragments thereof that bind FGFR3-IIIb and / or FGFR3-IIIc. In certain instances, the antibodies and antibody fragments thereof are useful in that they specifically bind FGFR3-IIIb (e.g., they are not pan-specific across FGFR1-4). Further, provided herein are pharmaceutical compositions comprising antibodies and antibody fragments and methods of using antibodies and antibody fragments described herein.

Description

FGFR3-IIIb-BINDING ANTIBODIESCROSS-REFERENCE

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 572,015, filed March 29, 2024; U.S. Provisional Application No. 63 / 653,116, filed May 29, 2024; and U.S. Provisional Application No. 63 / 741,769, filed January 3, 2025, the entirety of which are incorporated herein by reference in their entirety.SEQUENCE LISTING

[0002] The instant application contains a Sequence Listing which has been submitted electronically in XML file format and is hereby incorporated by reference in its entirety. Said XML copy, created on March 26, 2025, is named 65440-702.601_SL. xml and is 620,661 bytes in size.BACKGROUND

[0003] Cancer is a complex and multifaceted disease characterized by uncontrolled cell growth and is a global health challenge causing significant morbidity and mortality worldwide. Existing cancer therapies, including chemotherapy and radiation, often produce debilitating side effects, can fail to target cancer cells exclusively, thereby damaging healthy cells and tissues, and may lead to resistance or relapse.SUMMARY

[0004] Fibroblast growth factors (FGFs) and their receptors (FGFRs) are known oncologic drivers of cancers, however, currently approved therapies target FGFR receptors in pan-specific manner, leading to toxicity and side effects that impair overall treatment outcomes. Provided herein are antibodies that, unlike pan-specific modalities, target specific isoforms of the FGFR3 receptor: FGFR3-IIIb or FGFR3-IIIb and FGFR3-IIIc. Accordingly, in certain instances, the antibodies provided and exemplified herein are advantageous in that they specifically target FGFR3-IIIb or FGFR3-IIIb and FGFR3-IIIc. Moreover, in certain instances, the antibodies are additionally advantageous in that they are internalized by cells expressing FGFR3-IIIb, such as tumor cells.

[0005] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR- Illb comprising: a heavy chain variable domain comprising: a heavy chain complementarity determining region 1 (CDRH1) comprising the amino acid sequence of SEQ ID NO: 67; a heavy chain complementarity determining region 2 (CDRH2) comprising the amino acid sequence of SEQ ID NO: 673; a heavy chain complementarity determining region 3 (CDRH3) comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: alight chain complementarity determining region 1 (CDRL1) comprising the amino acid sequence of SEQ ID NO: 661; a light chain complementarity determining region 2 (CDRL2) comprising the amino acid sequence of SEQ ID NO: 662; and a light chain complementarity determining region 3 (CDRL3) comprising the amino acid sequence of SEQ ID NO: 663; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 689; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3comprising the amino acid sequence of SEQ ID NO: 672; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 64; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 65; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 66; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 68; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 76; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 77; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 78; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 82; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 83; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 84; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 88; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 89; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 90; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 163; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 164; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 165; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 166; a CDRL2 comprising the amino acid sequence of EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 168; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 91; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 92; a CDRH3 comprising theamino acid sequence of SEQ ID NO: 93; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 94; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 95; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 96; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 97; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 98; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 99; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 100; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 101; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 102; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 103; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 104; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 105; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 106; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 107; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 108; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 109; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 110; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 111; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 112; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 113; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 114; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 115; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 116; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 117; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 118; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 119; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 120; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of NY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 170; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 171; and a light chain variable domain comprising: a light chain complementarity determining region 1 (CDRL1 comprising the amino acid sequence of NSY; a CDRL2 comprising the amino acid sequence of RAN; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 174.

[0006] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb and FGFR3-IIIc comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 1; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 2; and a CDRH3 comprising the amino acid sequence of SEQ ID NO:3; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 4; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 5; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 6; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 7; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 8; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 9; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 10; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 11; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 12; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 13; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 14; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 15; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 16; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 17; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 18; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 19; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 20; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 21; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 22; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 23; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 24; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 25; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 26; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 27; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 28; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 29; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 30; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 152; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 153; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of STE; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 155; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 156.

[0007] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb and FGFR3-IIIc comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 31; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 32; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 33; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence ofSEQ ID NO: 34; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 35; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 36; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 37; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 38; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 39; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 40; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 41; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 42; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 43; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 44; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 45; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 46; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 47; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 48; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 49; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 50; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 51; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 52; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 53; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 54; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 55; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 56; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 57; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 58; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 59; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 60; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of GY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 158; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 159; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 161; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 162.

[0008] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb and FGFR3-IIIc comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 121; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 122; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 123; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 124; a CDRL2 comprising the amino acid sequence of SEQ ID NO:125; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 126; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 127; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 128; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 129; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 130; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 131; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 132; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 133; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 134; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 135; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 136; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 137; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 138; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 139; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 140; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 141; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 142; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 143; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 144; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 145; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 146; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 147; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 148; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 149; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 150; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 176; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 177; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SKY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 179; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 180.

[0009] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644; a heavy chain variable domain comprising: a CDRH1comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

[0010] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 657; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 661; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 662; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 663; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73;a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672.

[0011] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ IDNO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

[0012] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb comprising a heavy chain variable region and a light chain variable region, wherein: the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 677, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 676; the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 683, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 206; the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 677, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 206; or the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 684, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 682.

[0013] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb and FGFR3-IIIc comprising a heavy chain variable region and a light chain variable region, wherein: the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 209, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 210; or the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 201, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 202.

[0014] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the heavy chain variable region and the CDRs of the light chain variable region comprise SEQ ID NOS: 1-3, 4-6; 7-9, 10-12; 13-15, 16-18; 19-21, 22-24; 25-27, 28-30; 31-33, 34-36; 37-39, 40-42; 43-45, 46-48; 49-51, 52-54; 55-57, 58-60; 61-63, 64-66; 67-69, 70-72; 73- 75, 76-78; 79-81, 82-84; 85-87, 88-90; 91-93, 94-96; 97-99, 100-102; 103-105, 106-108; 109- 111, 112-114; 115-117, 118-120; 121-123, 124-126; 127-129, 130-132; 133-135, 136-138; 139- 141, 142-144; 145-147, 148-150; DY, 152-153, STE, 155-156; GY, 158-159, SY, 161-162; 163- 165, 166, EIS, 168; NY, 170-171, NS Y, RAN, 174; DY, 176-177, SKY, 179-180; 211-213, 214- 216; 217-219, 220-222; 223-225, 226-228; 229-231, 232-234; 235-237, 238-240; 241-243, 244-246; 247-249, 250-252; 253-255, 256-258; 259-261, 262-264; 265-267, 268-270; 271-273, 274-276; 277-279, 280-282; 283-285, 286-288; 289-291, 292, 294; 295-297, 298-300; 301-303, 304-306; 307-309, 310-312; 313-315, 316-318; 319-321, 322-324; 325-327, 328-330; 331-333, 334-336; 337-339, 340-342; 343-344, DDY, 346-348; 349-350, TTH, 352-354; 355-357, 358-360;361-363, 364-366; 367-369, 370-372; 373-375, 376-378; 379-381, 382-384; 385-387, 388-390; 391-393, 394-396; 397-399, 400-402; 403-405, 406-408; 409-411, 412-414; 415-417, 418-420; 421-423, 424-426; 427-429, 430-432; 433-435, 436-438; 439-441, 442-444; 445-447, 448-450; 451-453, 454-456; 457-459, 460-462; 463-465, 466-468; 469-471, 472-474; 475-477, 478-480; 481-483, 484-486; 487-489, 490-492; 493-495, 496-498; 499-501, 502-504; or 505-507, 508- 510; respectively.

[0015] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb and FGFR3-IIIc comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the heavy chain variable region and the CDRs of the light chain variable region comprise SEQ ID NOS: 1-3, 4-6; 7-9, 10-12; 13-15, 16-18; 19-21, 22-24; 25-27, 28-30; 31-33, 34-36; 37-39, 40-42; 43-45, 46-48; 49-51, 52-54; 55-57, 58-60; 121-123, 124-126; 127- 129, 130-132; 133-135, 136-138; 139-141, 142-144; 145-147, 148-150; DY, 152-153, STE, 155-156; DY, 158-159, SY, 161-162; DY, 176-177, SKY, 179-180; 211-213, 214-216; 217-219, 220-222; 223-225, 226-228; 229-231, 232-234; 235-237, 238-240; 241-243, 244-246; 247-249, 250-252; 253-255, 256-258; 259-261, 262-264; 265-267, 268-270; 271-273, 274-276; 277-279, 280-282; 283-285, 286-288; 289-291, 292, 294; 295-297, 298-300; 301-303, 304-306; 307-309, or 310-312; respectively.

[0016] In some embodiments, the antibody or antibody fragment comprises: a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 676; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 683 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 684 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 682; aheavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 202; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 203 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 204; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 205 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 207 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 208; or a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

[0017] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb comprising: a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 676; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 683 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 684 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 682; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or100% sequence identity to SEQ ID NO: 202; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 203 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 204; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 205 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 207 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 208; or a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

[0018] Provided and exemplified herein is an antibody or antibody fragment that binds FGFR3- Illb and FGFR3-IIIc comprising: a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 202; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 205 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 207 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 208; or a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

[0019] In some embodiments, the antibody or antibody fragment comprises an Fc domain. In some embodiments, the antibody or antibody fragment that binds FGFR3-IIIb comprises: a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 614 and a light chain having at least 80%, 85%,90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 615; a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 616 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 617; a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 618 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 619; a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 620 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 621; or a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 622 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 623. In some embodiments, the antibody or antibody fragment does not bind with an affinity of about or less than about 10 X 10'8M to FGFR1, FGFR2, or FGFR4. In some embodiments, the antibody or antibody fragment binds to a FGFR3- Illb protein with an equilibrium dissociation constant (KD) equal to or less than 10 x 10'8M. In some embodiments, the FGFR3-IIIb protein comprises the amino acid sequence of SEQ ID NO: 191, 195, or 197. In some embodiments, the antibody is internalized by a cell expressing FGFR3-IIIb. In some embodiments, the cell is a HEK-293 cell expressing FGFR3-IIIb.

[0020] Provided and exemplified herein is a pharmaceutical composition comprising: an antibody and antibody fragment comprising means for binding FGFR3-IIIb; and a pharmaceutically acceptable carrier.

[0021] Provided and exemplified herein is a pharmaceutical composition comprising: an antibody and antibody fragment comprising means for binding FGFR3-IIIb and internalizing into a cell expressing FGFR3-IIIb; and a pharmaceutically acceptable carrier.

[0022] Provided and exemplified herein is a method of inhibiting proliferation of a cell expressing FGFR3-IIIb, the method comprising: contacting a cell with the antibody or antibody fragment described herein or the pharmaceutical composition described herein. In some embodiments, the antibody or antibody fragment is internalized by the cell. In some embodiments, the cell is a Ba / F3 cell expressing FGFR3-IIIb.

[0023] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable domain comprising: a heavy chain complementarity determining region 1 (CDRH1) comprising the amino acid sequence of SEQ ID NO: 67; a heavy chain complementarity determining region 2(CDRH2) comprising the amino acid sequence of SEQ ID NO: 673; a heavy chain complementarity determining region 3 (CDRH3) comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a light chain complementarity determining region 1 (CDRL1) comprising the amino acid sequence of SEQ ID NO: 661; a light chain complementarity determining region 2 (CDRL2) comprising the amino acid sequence of SEQ ID NO: 662; and a light chain complementarity determining region 3 (CDRL3) comprising the amino acid sequence of SEQ ID NO: 663; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 64; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 65; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 66; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acidsequence of SEQ ID NO: 68; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 76; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 77; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 78; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 82; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 83; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 84; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 88; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 89; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 90; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 163; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 164; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 165; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 166; a CDRL2 comprising the amino acid sequence of EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 168; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 91; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 92; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 93; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 94; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 95; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 96; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 97; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 98; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 99; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 100; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 101; and aCDRL3 comprising the amino acid sequence of SEQ ID NO: 102; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 103; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 104; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 105; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 106; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 107; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 108; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 109; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 110; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 111; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 112; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 113; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 114; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 115; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 116; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 117; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 118; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 119; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 120; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of NY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 170; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 171; and a light chain variable domain comprising: a light chain complementarity determining region 1 (CDRL1 comprising the amino acid sequence of NSY; a CDRL2 comprising the amino acid sequence of RAN; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 174.

[0024] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 1; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 2; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 3; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 4; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 5; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 6; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 7; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 8; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 9; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 10; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 11; and a CDRL3 comprising the aminoacid sequence of SEQ ID NO: 12; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 13; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 14; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 15; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 16; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 17; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 18; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 19; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 20; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 21; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 22; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 23; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 24; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 25; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 26; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 27; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 28; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 29; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 30; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 152; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 153; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of STE; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 155; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 156.

[0025] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 31; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 32; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 33; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 34; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 35; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 36; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 37; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 38; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 39; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 40; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 41; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 42; a heavy chain variable domain comprising: a CDRH1comprising the amino acid sequence of SEQ ID NO: 43; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 44; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 45; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 46; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 47; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 48; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 49; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 50; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 51; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 52; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 53; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 54; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 55; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 56; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 57; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 58; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 59; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 60; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of GY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 158; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 159; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 161; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 162.

[0026] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 121; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 122; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 123; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 124; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 125; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 126; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 127; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 128; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 129; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 130; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 131; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 132; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 133; a CDRH2comprising the amino acid sequence of SEQ ID NO: 134; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 135; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 136; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 137; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 138; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 139; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 140; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 141; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 142; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 143; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 144; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 145; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 146; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 147; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 148; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 149; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 150; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 176; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 177; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SKY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 179; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 180.

[0027] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acidsequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; ora heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

[0028] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 657; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 661; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 662; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 663; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising theamino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672.

[0029] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain- 1 -variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

[0030] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the heavy chain variable region and the CDRs of the light chain variable region comprise SEQ ID NOS: 1-3, 4-6; 7-9, 10-12; 13-15, 16-18; 19- 21, 22-24; 25-27, 28-30; 31-33, 34-36; 37-39, 40-42; 43-45, 46-48; 49-51, 52-54; 55-57, 58-60; 61-63, 64-66; 67-69, 70-72; 73-75, 76-78; 79-81, 82-84; 85-87, 88-90; 91-93, 94-96; 97-99, 100-102; 103-105, 106-108; 109-111, 112-114; 115-117, 118-120; 121-123, 124-126; 127-129, 130-132; 133-135, 136-138; 139-141, 142-144; 145-147, 148-150; DY, 152-153, STE, 155-156; GY, 158-159, SY, 161-162; 163-165, 166, EIS, 168; NY, 170-171, NS Y, RAN, 174; DY, 176- 177, SKY, 179-180; 211-213, 214-216; 217-219, 220-222; 223-225, 226-228; 229-231, 232- 234; 235-237, 238-240; 241-243, 244-246; 247-249, 250-252; 253-255, 256-258; 259-261, 262-264; 265-267, 268-270; 271-273, 274-276; 277-279, 280-282; 283-285, 286-288; 289-291, 292,294; 295-297, 298-300; 301-303, 304-306; 307-309, 310-312; 313-315, 316-318; 319-321, 322-324; 325-327, 328-330; 331-333, 334-336; 337-339, 340-342; 343-344, DDY, 346-348; 349-350, TTH, 352-354; 355-357, 358-360; 361-363, 364-366; 367-369, 370-372; 373-375, 376- 378; 379-381, 382-384; 385-387, 388-390; 391-393, 394-396; 397-399, 400-402; 403-405, 406-408; 409-411, 412-414; 415-417, 418-420; 421-423, 424-426; 427-429, 430-432; 433-435, 436-438; 439-441, 442-444; 445-447, 448-450; 451-453, 454-456; 457-459, 460-462; 463-465, 466-468; 469-471, 472-474; 475-477, 478-480; 481-483, 484-486; 487-489, 490-492; 493-495, 496-498; 499-501, 502-504; or 505-507, 508-510; respectively.

[0031] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable region and a light chain variable region, wherein the CDRs of the heavy chain variable region and the CDRs of the light chain variable region comprise SEQ ID NOS: 1-3, 4-6; 7-9, 10-12; 13-15, 16-18; 19- 21, 22-24; 25-27, 28-30; 31-33, 34-36; 37-39, 40-42; 43-45, 46-48; 49-51, 52-54; 55-57, 58-60; 121-123, 124-126; 127-129, 130-132; 133-135, 136-138; 139-141, 142-144; 145-147, 148-150; DY, 152-153, STE, 155-156; DY, 158-159, SY, 161-162; DY, 176-177, SKY, 179-180; 211- 213, 214-216; 217-219, 220-222; 223-225, 226-228; 229-231, 232-234; 235-237, 238-240; 241- 243, 244-246; 247-249, 250-252; 253-255, 256-258; 259-261, 262-264; 265-267, 268-270; 271- 273, 274-276; 277-279, 280-282; 283-285, 286-288; 289-291, 292, 294; 295-297, 298-300; 301- 303, 304-306; 307-309, or 310-312; respectively.

[0032] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the light chain variable region and the CDRs of the heavy chain variable region comprise SEQ ID NOS: 70-72, 67, 689, 69; 70-72, 67, 673, 69; or 70, 71, 660, 67, 673, 69. In some embodiments, the antibody or antibody fragment that binds FGFR3-IIIb comprises: a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 676; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 683 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 684 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 682.

[0033] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the light chain variable region and the CDRs of the heavy chain variable region comprise SEQ ID NOS: 10-12, 7-9. In some embodiments, the antibody or antibody fragment that binds FGFR3-IIIb and FGFR3-IIIc comprises: a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 202.

[0034] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the light chain variable region and the CDRs of the heavy chain variable region comprise SEQ ID NOS: 130-132, 127-129. In some embodiments, the antibody or antibody fragment that binds FGFR3-IIIb and FGFR3-IIIc comprises: a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region(VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

[0035] In some embodiments, the antibody or antibody fragment comprises: a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 676; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 683 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 684 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 682; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 202; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 203 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 204; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 205 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 207 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 208; or a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

[0036] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising: a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 676; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 202; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 203 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 204; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 205 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206; a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 207 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 208; or a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

[0037] In some embodiments, the antibody or antibody fragment comprises a CHI domain, e.g., of SEQ ID NO: 685. In some embodiments, the antibody or antibody fragment comprises a CH2 domain, e.g., of SEQ ID NO: 686. In some embodiments, the antibody or antibody fragment comprises a CH3 domain, e.g., of SEQ ID NO: 687. In some embodiments, the antibody or antibody fragment comprises a Kappa domain, e.g., of SEQ ID NO: 688. In some embodiments, the antibody or antibody fragment comprises an Fc domain, e.g., SEQ ID NO: 611 or 612.

[0038] In some embodiments, the antibody or antibody fragment that binds FGFR3-IIIb comprises: a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 677 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 676; a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%,97%, 98%, 99%, or 100% sequence identity to SEQ NO: 614 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 615; a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 616 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 617; a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 618 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 619; a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 620 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 621; or a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 622 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 623. In some embodiments, the antibody or antibody fragment does not bind with an affinity of about or less than about 10 X 10'8M to FGFR1, FGFR2, or FGFR4. In some embodiments, the antibody or antibody fragment binds to a FGFR3-IIIb protein with an equilibrium dissociation constant (KD) equal to or less than 10 x 10"8M. In some embodiments, FGFR3-IIIb protein comprises the amino acid sequence of SEQ ID NO: 191, 195, or 197. In some embodiments, the antibody is internalized by a cell expressing FGFR3-IIIb. In some embodiments, the cell is a HEK-293 cell expressing FGFR3-IIIb.

[0039] Provided and exemplified herein is a pharmaceutical composition comprising: an antibody and antibody fragment comprising means for binding FGFR3-IIIb; and a pharmaceutically acceptable carrier.

[0040] Provided and exemplified herein is a pharmaceutical composition comprising: an antibody and antibody fragment comprising means for binding FGFR3-IIIb and internalizing into a cell expressing FGFR3-IIIb; and a pharmaceutically acceptable carrier.

[0041] Provided and exemplified herein is a method of inhibiting proliferation of a cell expressing FGFR3-IIIb, the method comprising: contacting a cell with the antibody or antibody fragment described herein or the pharmaceutical described herein. In some embodiments, the antibody or antibody fragment is internalized by the cell. In some embodiments, the cell is a Ba / F3 cell expressing FGFR3-IIIb.

[0042] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprising:(i) a heavy chain variable domain comprising: a heavy chain complementarity determining region 1 (CDRH1) comprising the amino acid sequence of SEQ ID NO: 1; a heavy chain complementarity determining region 2 (CDRH2) comprising the amino acid sequence of SEQ ID NO: 2; and a heavy chain complementarity determining region 3 (CDRH3) comprising the amino acid sequence of SEQ ID NO: 3; and a light chain variable domain comprising: a light chain complementarity determining region 1 (CDRL1) comprising the amino acid sequence of SEQ ID NO: 4; a light chain complementarity determining region 2 (CDRL2) comprising the amino acid sequence of SEQ ID NO: 5; and a light chain complementarity determining region 3 (CDRL3) comprising the amino acid sequence of SEQ ID NO: 6;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 7; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 8; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 9; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 10; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 11; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 12;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 13; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 14; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 15; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 16; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 17; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 18;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 19; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 20; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 21; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 22; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 23; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 24;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 25; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 26; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 27; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 28; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 29; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 30; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 152; a CDRH3comprising the amino acid sequence of SEQ ID NO: 153; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of STE a CDRL2 comprising the amino acid sequence of SEQ ID NO: 155; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 156.

[0043] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 31; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 32; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 33; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 34; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 35; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 36;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 37; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 38; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 39; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 40; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 41; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 42;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 43; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 44; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 45; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 46; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 47; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 48;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 49; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 50; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 51; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 52; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 53; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 54;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 55; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 56; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 57; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 58; aCDRL2 comprising the amino acid sequence of SEQ ID NO: 59; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 60; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of GY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 158; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 159; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 161; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 162.

[0044] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 64; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 65; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 66;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 68; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 76; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 77; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 78;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 82; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 83; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 84;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 88; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 89; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 90; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 163; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 164; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 165; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 166; a CDRL2 comprising the amino acid sequence of EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 168.

[0045] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 91; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 92; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 93; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 94; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 95; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 96;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 97; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 98; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 99; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 100; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 101; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 102;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 103; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 104; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 105; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 106; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 107; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 108;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 109; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 110; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 111; and a light chainvariable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 112; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 113; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 114;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 115; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 116; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 117; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO:118; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 119; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 120; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of NY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 170; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 171; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of NSY; a CDRL2 comprising the amino acid sequence of RAN; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 174.

[0046] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 121; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 122; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 123; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 124; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 125; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 126;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 127; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 128; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 129; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 130; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 131; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 132;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 133; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 134; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 135; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 136; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 137; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 138;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 139; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 140; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 141; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 142; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 143; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 144;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 145; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 146; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 147; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 148; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 149; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 150; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 176; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 177; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SKY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 179; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 180.

[0047] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variabledomain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

[0048] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 657; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 661; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 662; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 663;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672.

[0049] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variabledomain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

[0050] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 661; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 662; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 663;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672.

[0051] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the heavy chain variable region and the CDRs of the light chain variable region comprise SEQ ID NOS: 1-3, 4-6; 7-9, 10-12; 13-15, 16-18; 19-21, 22-24; 25-27, 28-30; 31-33, 34-36; 37-39, 40-42; 43-45, 46-48; 49-51, 52-54; 55-57, 58-60; 61-63, 64-66; 67-69, 70-72; 73- 75, 76-78; 79-81, 82-84; 85-87, 88-90; 91-93, 94-96; 97-99, 100-102; 103-105, 106-108; 109- 111, 112-114; 115-117, 118-120; 121-123, 124-126; 127-129, 130-132; 133-135, 136-138; 139- 141, 142-144; 145-147, 148-150; DY, 152-153, STE, 155-156; GY, 158-159, SY, 161-162; 163- 165, 166, EIS, 168; NY, 170-171, NS Y, RAN, 174; DY, 176-177, SKY, 179-180; 211-213, 214- 216; 217-219, 220-222; 223-225, 226-228; 229-231, 232-234; 235-237, 238-240; 241-243, 244-246; 247-249, 250-252; 253-255, 256-258; 259-261, 262-264; 265-267, 268-270; 271-273, 274-276; 277-279, 280-282; 283-285, 286-288; 289-291, 292, 294; 295-297, 298-300; 301-303, 304-306; 307-309, 310-312; 313-315, 316-318; 319-321, 322-324; 325-327, 328-330; 331-333, 334-336; 337-339, 340-342; 343-344, DDY, 346-348; 349-350, TTH, 352-354; 355-357, 358-360; 361-363, 364-366; 367-369, 370-372; 373-375, 376-378; 379-381, 382-384; 385-387, 388-390; 391-393, 394-396; 397-399, 400-402; 403-405, 406-408; 409-411, 412-414; 415-417, 418-420; 421-423, 424-426; 427-429, 430-432; 433-435, 436-438; 439-441, 442-444; 445-447, 448-450; 451-453, 454-456; 457-459, 460-462; 463-465, 466-468; 469-471, 472-474; 475-477, 478-480;481-483, 484-486; 487-489, 490-492; 493-495, 496-498; 499-501, 502-504; or 505-507, 508- 510; respectively.

[0052] Also provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the heavy chain variable region and the CDRs of the light chain variable region comprise SEQ ID NOS: 1-3, 4-6; 7-9, 10-12; 13-15, 16-18; 19-21, 22-24; 25-27, 28-30; 31-33, 34-36; 37-39, 40-42; 43-45, 46-48; 49-51, 52-54; 55-57, 58-60; 121-123, 124-126; 127-129, 130-132; 133-135, 136-138; 139-141, 142-144; 145-147, 148-150; DY 152-153, DY, 152-153, STE, 155-156; GY, 158-159, SY, 161-162; DY, 176-177, SKY, 179-180; 211-213, 214-216; 217-219, 220-222; 223-225, 226-228; 229-231, 232-234; 235-237, 238-240; 241-243, 244-246; 247-249, 250-252; 253-255, 256-258; 259-261, 262-264; 265-267, 268-270; 271-273,274-276; 277-279, 280-282; 283-285, 286-288; 289-291, 292, 294; 295-297, 298-300; 301-303, 304-306; 307-309, or 310-312; respectively.BRIEF DESCRIPTION OF THE DRAWINGS

[0053] FIGS. 1A-1B show binding data for FGFR3-IIIb antibodies against FGFR3-IIIb (FIG. 1A) or FGFR3-IIIc (FIG. IB).

[0054] FIGS. 2A-2B show binding profiles and EC50 data for binding of FGFR3-IIIb antibodies to cells expressing FGFR3-IIIb (FIG. 2A) or FGFR3-IIIc (FIG. 2B).

[0055] FIG. 3 shows the internalization of chimeric FGFR3-IIIb antibodies on FGFR3-IIIb- 293T cells as measured by Incucyte.

[0056] FIG. 4 shows the binding of the chimeric antibody with hFGFR3 as measured by ELISA.

[0057] FIG. 5 shows the effect of FGFR3-IIIb antibody on the proliferation of FGFR3- IIIb / BaF3 cells.

[0058] FIG. 6 shows the binding of the chimeric antibody with FGFR3-IIIb, FGFR1, FGFR2, and FGFR4 as measured by ELISA.

[0059] FIGS. 7A-7B show binding profile of antibodies tested in bladder cancer cell line, RT112 / 84 (FIG. 7A) and SW780 (FIG. 7B). FIGS. 7C-7E show binding profile of antibodies tested in 293T cells over-expressing FGFR3-IIIb (FIG. 7C), 293T cells over-expressing FGFR3-IIIb with S249C mutation (FIG. 7D), and 293T cells over-expressing FGFR3-IIIc (FIG. 7E). FIG. 7F shows graph of EC50 of antibodies binding to 293T cells over-expressing FGFR3- Illb. FIG. 7G shows binding profiles of antibodies against FGFR3-IIIb and FGFR3-IIIc by FACS.

[0060] FIG. 8A shows binding profiles of chimeric antibodies to 293T cells over-expressing FGFR3-IIIb, FGFR3-IIIc, FGFR3-IIIb with R248C mutation, or FGFR3-IIIb with S249C mutation (for each grouping from left to right: 85B11 (non-blocking), 54H7, 28A7, 10C12, 29E5, hlgGl, 309-hIgGl (non-blocking), and FAYA hlgGl). FIG. 8B shows FACS results of EC50 of chimeric antibodies binding to 293T cells over-expressing FGFR3. FIG. 8C shows ELISA results of EC50 of chimeric antibodies binding to 293T cells over-expressing FGFR3- Illb. FIGS. 8D-8F show additional binding profiles of chimeric antibodies tested in RT4 cell line (FIG. 8D), NCI-H1781 cell line (FIG. 8E), and FaDu cell line (FIG. 8F).

[0061] FIGS. 9A-9D show binding profiles of humanized antibodies to in 293T cells overexpressing FGFR3-IIIb (FIG. 9A), 293T cells over-expressing FGFR3-IIIc (FIG. 9B), RT112 / 84 cell line (FIG. 9C), and RT4 cell line (FIG. 9D).

[0062] FIG. 10 show FACS results of EC50 of hl012 antibodies binding to 293T cells overexpressing FGFR3-IIIb.

[0063] FIGS. 11A-11B show results of antibody internalization of humanized antibodies in two repeat experiments with 293T cells overexpressing FGFR3-IIIb. FIGS. 11C-11G show results of Antibody Dependent Cellular Cytotoxicity (ADCC) Assays (FIG. 11C) and Antibody- Dependent Cellular Phagocytosis (ADCP) Assay (FIG. 11D) using RT112 / 84 cell line. FIG. HE shows results of ADCC assays using 293T cells over-expressing FGFR3-IIIb. FIG. HF shows results of antibody internalization rate. FIG. 11G shows results of cytotoxicity assay.

[0064] FIGS. 12A-12C show cytotoxicity of antibodies tested in 2D culture using RT112 / 84 cell line (FIG. 12A), in 3D culture using RT112 / 84 cell line (FIG. 12B), and in 293T cells overexpressing FGFR3-IIIb (FIG. 12C).DETAILED DESCRIPTION

[0065] Fibroblast growth factor receptors (FGFRs) are highly conserved single-pass transmembrane proteins, composed of an extracellular domain (ECD), a transmembrane domain, and an intracellular tyrosine kinase domain. The ECD consists of three immunoglobulin-like subdomains (D1-D3) with an acidic box and a heparin-binding site. Fibroblast growth factors (FGFs) and heparin or heparan sulfate proteoglycans bind to the D2 and D3 subdomains of FGFR, leading to receptor dimerization and trans-autophosphorylation, and each specific phosphorylation site can bind and phosphorylate substrates to activate multiple signal transduction pathways. The DI subdomain generally engages in weak interactions with the D2- D3 subdomains, which was shown to induce sustainable autoinhibition.

[0066] FGFR3 is one of four members of the FGFR family, and has two major alternatively spliced isoforms, designated Illb and IIIc. Both isoforms differ in the second half of D3 subdomain, and consequently in ligand-binding affinity and specificity. The alternative splicing events occur in a tissue specific fashion, resulting in distinct tissue distribution of isoforms. While the Illb isoform is expressed in epithelial cells, IIIc isoform is mainly expressed in mesenchymal cells.

[0067] FGFR3 plays an important role in different important physiological cellular processes, such as regulation of cell survival, proliferation, differentiation, migration and angiogenesis. Aberrantly activated and / or overexpressed FGFR3 has been observed in various human malignancies.FGFR3-IIIb-binding antibodies

[0068] Provided and exemplified herein are antibodies and antibody fragments that bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc. As such, an antibody fragment that binds toFGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc, comprises an antigen-binding fragment, where the antigen is FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc. Non-limiting example antibodies and antibody fragments are provided herein, e.g., at Tables 1, 2, 10 and 18.Table 1: FGFR3-IIIb antibody CDRs binding FGFR3-IIIbTable 2: FGFR3-IIIb / IIIc antibody CDRs binding FGFR3-IIIb and FGFR3-IIIc307-309, 310-312

[0069] In some instances, an antibody or antibody fragment that binds to FGFR3-IIIb binds to FGFR3-IIIb with a KD of less than about 10 x 10'8M. In some instances, an antibody or antibody fragment that binds to FGFR3-IIIb is specific for FGFR3-IIIb. In some instances, an antibody or antibody fragment specific for FGFR3-IIIb does not bind to another FGFR antigen with a KD of less than about 10 X 10'8M. Another FGFR antigen may include FGFR1, FGFR2, and / or FGFR3. In some instances, another FGFR antigen is FGFR3-IIIc. Non-limiting example binding assays are provided in the Examples, e.g., Example 5. Non-limiting examples antibodies and antibody fragments are provided herein, e.g., at Tables 1, 2, 10 and / or 18.

[0070] An antibody or antibody fragment that binds to FGFR3-IIIb may include an antibody or antibody fragment that binds to FGFR3-IIIb and FGFR3-IIIc. An antibody or antibody fragment that binds to FGFR3-IIIb and FGFR3-IIIc may include an antibody or antibody fragment that is specific for FGFR3-IIIb and specific for FGFR3-IIIc. In some instances, an antibody or antibody fragment specific for FGFR3-IIIb and FGFR3-IIIc does not bind to another FGFR antigen with a KD about or less than about 10 X 10'8M. Another FGFR antigen may include FGFR1, FGFR2, and / or FGFR3. In some instances, an antibody or antibody fragment specific for FGFR3-IIIb and FGFR3-IIIc binds to FGFR3-IIIb with a KD about or less than about 10 X 10'8M and binds to FGFR3-IIIc with a KD about or less than about 10 X 10'8M Non-limiting examples antibodies and antibody fragments are provided herein, e.g., at Tables 1, 2, 10 and / or 18.

[0071] In certain instances, the antibodies and antibody fragments are useful in that they specifically bind FGFR3-IIIb, or FGFR3-IIIb and FGFR3-IIIc (e.g., they are not pan-specific across FGFR1-4). In certain instances, the antibodies and antibody fragments herein do not bind to FGFR1, FGFR2, or FGFR4 with a KD about or less than about 10 X 10'8. Non-limiting examples antibodies and antibody fragments are provided herein, e.g., at Tables 1, 2, 10 and / or 18.

[0072] In certain instances, the antibodies and antibody fragments are useful in that they are internalized by cells expressing FGFR3-IIIb and / or FGFR3-IIIc. Non-limiting examples antibodies and antibody fragments are provided herein, e.g., at Tables 1, 2, 10 and / or 18.

[0073] In some embodiments, provided are antibodies and antibody fragments having means for binding FGFR3-IIIb. In certain embodiments, provided are antibodies and antibody fragments having means for binding FGFR3-IIIb and internalizing into a cell expressing FGFR3-IIIb. In some embodiments, provided are antibodies and antibody fragments having means for binding FGFR3-IIIb and FGFR3-IIIc. In certain embodiments, provided are antibodies and antibody fragments having means for binding FGFR3-IIIb and FGFR3-IIIc and internalizing into a cellexpressing FGFR3-IIIb and / or FGFR3-IIIc. Non-limiting examples antibodies and antibody fragments are provided herein, e.g., at Tables 1, 2, 10 and / or 18.

[0074] In some embodiments, antibodies and / or antibody fragments that bind FGFR3-IIIb (e.g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) are internalized by a cell expressing FGFR3-IIIb. In some embodiments, the cell is a HEK-293 cell expressing FGFR3-IIIb. Non-limiting examples antibodies and antibody fragments are provided herein, e.g., at Tables 1, 2, 10 and / or 18.

[0075] In some embodiments, the antibodies and / or antibody fragments that bind FGFR3-IIIb (e g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) bind to a FGFR3-IIIb protein with an equilibrium dissociation constant (KD) equal to or less than 100 * 10'9M, less than 50 x 10'9M, less than 25 x 10'9M, less than 10 x 10'9M, or less than 5 x 10'9M. In certain embodiments, the FGFR3-IIIb protein comprises the amino acid sequence of SEQ ID NO: 191, 193, 195, or 197. In certain embodiments, antibodies and / or antibody fragments bind FGFR3-IIIc. The FGFR3- Illc-binding antibody or FGFR3-IIIc-binding antibody fragment binds to a FGFR3-IIIc protein (e.g., as measured by ELISA or cell-binding in the Examples). In certain embodiments, the FGFR3-IIIc protein comprises the amino acid sequence of SEQ ID NO: 192, 194, 196, or 198. In certain embodiments, the antibody and / or antibody fragment that binds FGFR3-IIIb (e.g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) does not bind to FGFR1, FGFR2, or FGFR4. Nonlimiting examples antibodies and antibody fragments are provided herein, e.g., at Tables 1, 2, 10 and / or 18.

[0076] An antibody and / or antibody fragment that binds FGFR3-IIIb generally refers to and / or includes an antibody that binds a FGFR3-3-IIIb protein comprising a protein having the amino acid sequence of SEQ ID NO: 191. Generally, a FGFR3-IIIb antibody or FGFR3-IIIb-binding antibody fragment is specific for a FGFR3-IIIb protein (e.g., selectively recognize and bind to a FGFR3-IIIb protein). A FGFR3-IIIc-binding antibody or FGFR3-IIIc-binding antibody fragment generally refers to and / or includes an antibody that binds a FGFR3-3-IIIc protein comprising a protein having the amino acid sequence of SEQ ID NO: 192. Generally, a FGFR3-IIIc antibody or FGFR3-IIIc-binding antibody fragment is specific for a FGFR3-IIIc protein (e.g., selectively recognize and bind to a FGFR3-IIIc protein). Binding can be determined by bio-layer interferometry, surface plasmon resonance, isothermal titration calorimetry, and / or ELISA. Affinity generally refers to and / or includes the strength of the sum total of noncovalent interactions between a single binding site of a molecule (e.g., an antibody) and its binding partner (e.g., an antigen such as FGFR3-IIIb, and FGFR3-IIIc). Unless indicated otherwise, binding affinity generally encompasses and refers to intrinsic binding affinity which reflects a 1 : 1 interaction between members of a binding pair (e.g., antibody and antigen). The affinity of an antibody for an antigen (e.g., FGFR3-IIIb or FGFR3-IIIc) can generally be represented by thedissociation constant (KD). Affinity can be measured and determined by bio-layer interferometry, surface plasmon resonance, isothermal titration calorimetry, and / or ELISA.

[0077] FGFR3 generally refers to and / or includes the protein encoded by the FGFR3 gene and functions in cell division, cell maturation, formation of new blood vessels, wound healing, and bone growth, development, and maintenance. FGFR3 alternative splice variants result in FGFR3-IIIb and FGFR3-IIIc isoforms of the FGFR3 protein. FGFR3-IIIb generally refers to and / or includes a protein encoded by the FGFR3 gene. FGFR3-IIIc generally refers to and / or includes a protein encoded by the FGFR3 gene. In certain embodiments, the FGFR3 gene refers to NCBI GenelD 2261 and / or HGNC ID: HGNC: 3690, which includes sequence information on isoform Illb. In certain embodiments, a FGFR3-IIIb protein refers to and includes the protein(s) of UniProt ID: P22607-2. In certain instances, FGFR3-IIIb comprises a protein comprising the amino acid sequence of SEQ ID NO: 191 or a homologue or an orthologue or variant thereof (e.g., as referenced in NCBI GenelD 2261 and / or HGNC ID: HGNC: 3690). In certain embodiments, a FGFR3-IIIc protein refers to and includes the protein(s) of UniProt ID: P22607-1. In certain instances, FGFR3-IIIc comprises a protein comprising the amino acid sequence of SEQ ID NO: 192 or a homologue or an orthologue or variant thereof (e.g., as referenced in NCBI GenelD 2261 and / or HGNC ID: HGNC: 3690).

[0078] In certain instances, FGFR3-IIIb comprises an amino acid sequence having at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% sequence identity to of SEQ ID NO: 191. In certain instances, FGFR3-IIIb comprises an amino acid sequence having at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% sequence identity to of SEQ ID NO: 195. In certain instances, FGFR3-IIIb comprises an amino acid sequence having at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% sequence identity to of SEQ ID NOs: 197. In certain instances, FGFR3-IIIc comprises an amino acid sequence having at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% sequence identity to of SEQ ID NO: 192.

[0079] In certain embodiments, the antibodies and / or antibody fragments that bind FGFR3-IIIb (e g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) comprise an Fc region. In certain embodiments, the Fc region is an IgG Fc region. The Fc region may comprise a sequence of SEQ ID NO: 611 or 612.

[0080] In certain embodiments, the antibodies and / or antibody fragments that bind FGFR3-IIIb (e.g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) comprise a light chain constant region. For example, human kappa having SEQ ID NO: 199, or a sequence at least about 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% identical to of SEQ ID NO: 199. In certain embodiments, the antibodies and / or antibody fragments that bind FGFR3-IIIb (e.g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) comprise a Kappa domain, e.g., of SEQ ID NO: 688. In certain embodiments, theantibodies and / or antibody fragments that bind FGFR3-IIIb (e.g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) comprise a heavy chain constant region. For example, human IgGl constant region having SEQ ID NO: 200, or a sequence at least about 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% identical to of SEQ ID NO: 200. In certain embodiments, the antibodies and / or antibody fragments that bind FGFR3-IIIb (e g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) comprise a CHI domain, e.g., of SEQ ID NO: 685. In certain embodiments, the antibodies and / or antibody fragments that bind FGFR3-IIIb (e.g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) comprise a CH2 domain, e.g., of SEQ ID NO: 686. In certain embodiments, the antibodies and / or antibody fragments that bind FGFR3-IIIb (e.g., FGFR3-IIIb, FGFR3-IIIb and FGFR3-IIIc) comprise a CH3 domain, e.g., of SEQ ID NO: 687.

[0081] Antibody is used in the broadest sense and generally refers to and / or includes monoclonal antibodies, multi-valent antibodies, multi-specific, antigen-binding fragments of antibodies that bind a FGFR3-IIIb protein. Antigen-binding fragments of antibodies (antigenbinding antibody fragments) generally refer to and / or include antibody -derived proteins that comprise a functional set of CDRs (e.g., a CDR-H1-3 and CDR-L1-3) that bind a FGFR3-IIIb protein and have a molecule weight less than a full length IgG antibody (e.g., a molecular weight less than -150,00 Daltons). In certain embodiments, an antigen-binding antibody fragment (e.g., a FGFR3 -binding fragment) includes: fragment antigen binding (Fab) fragments, F(ab’)2 fragments, Fab' fragments, Fv fragments, IgG (rlgG) fragments, and single chain antibody fragments, including single chain variable fragments (sFv or scFv). Antibodies and antigenbinding fragments of antibodies generally encompass genetically engineered, and / or otherwise modified forms of immunoglobulins, such as intrabodies, peptibodies, chimeric antibodies, fully human antibodies, humanized antibodies, and heteroconjugate antibodies, multi-specific antibodies, multi-valent antibodies, diabodies, triabodies, and tetrabodies, tandem di-scFv, tandem tri-scFv. A full-length antibody, intact antibody, and / or whole antibody are interchangeable, and generally include and / or refer to an antibody having a structure substantially similar to a native antibody structure having heavy chains that contain an Fc region and / or include antibodies of any class or sub-class, including IgG and sub-classes thereof (e.g., IgGl and IgG4), IgM, IgE, IgA, and IgD.

[0082] Complementarity determining regions (CDRs) generally include amino acids (e.g., noncontiguous or contiguous) within antibody variable regions that confer antigen specificity and / or binding affinity (e.g., to FGFR3-IIIb or FGFR3-IIIc). In general, there are three CDRs in each heavy chain variable region (CDR-H1, CDR-H2, CDR-H3) and three CDRs in each light chain variable region (CDR-L1, CDR-L2, CDR-L3). Framework regions (FRs) generally refer to and / or include non-CDR regions of the heavy and light chain variable regions. In general, thereare four FRs in each full-length heavy chain variable region (FR-H1, FR-H2, FR-H3, and FR- H4), and four FRs in each full-length light chain variable region (FR-L1, FR-L2, FR-L3, and FR-L4).

[0083] Variable regions (also referred to as variable domains) generally refer to and / or include the domain of an antibody heavy or light chain that is involved in binding the antibody to antigen (e.g., a single variable domain comprises a CDR 1, CDR 2, and CDR 3). The variable domains of the heavy chain and light chain (VH and VL, respectively) of a native antibody generally have similar structures, with each domain comprising four conserved framework regions (FRs) and three CDRs. In certain instances, a single VH or VL domain can be sufficient to confer antigen-binding specificity (e.g., binding to FGFR3-IIIb).

[0084] Fc region generally encompasses and / or refers to a C-terminal region of an immunoglobulin heavy chain that contains at least a portion of the constant region. Generally, the Fc region includes an immunoglobulin CH2 and CH3 domain (e.g., an IgG CH2 and CH3 domain). The term includes native sequence Fc regions and variant Fc regions. In one embodiment, a human IgG heavy chain Fc region extends from Cys226, or from Pro230, to the carboxyl-terminus of the heavy chain, per EU numbering. However, the C-terminal lysine (Lys447) of the Fc region may or may not be present. Unless otherwise specified herein, numbering of amino acid residues in the Fc region or constant region is according to the EU numbering system, also called the EU index, as described in Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD, 1991. In certain embodiments, the Fc region include IgG and sub-classes thereof (e.g., IgGl and IgG4), IgM, IgE, IgA, and / or IgD heavy chain constant regions and / or heavy chain constant regions derived from IgG and sub-classes thereof (e.g., IgGl and IgG4), IgM, IgE, IgA, and IgD.

[0085] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, comprising:(i) a heavy chain variable domain comprising: a heavy chain complementarity determining region 1 (CDRH1) comprising the amino acid sequence of SEQ ID NO: 1; a heavy chain complementarity determining region 2 (CDRH2) comprising the amino acid sequence of SEQ ID NO: 2; and a heavy chain complementarity determining region 3 (CDRH3) comprising the amino acid sequence of SEQ ID NO: 3; and a light chain variable domain comprising: a light chain complementarity determining region 1 (CDRL1) comprising the amino acid sequence of SEQ ID NO: 4; a light chain complementarity determining region 2 (CDRL2) comprising the amino acid sequence of SEQ ID NO: 5; and a light chain complementarity determining region 3 (CDRL3) comprising the amino acid sequence of SEQ ID NO: 6;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 7; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 8; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 9; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 10; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 11; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 12;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 13; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 14; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 15; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 16; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 17; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 18;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 19; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 20; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 21; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 22; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 23; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 24;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 25; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 26; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 27; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 28; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 29; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 30; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 152; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 153; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of STE; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 155; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 156.

[0086] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 181; and the light chain variable domain has at least about or about 70%, 75%,80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 182. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 181 and the light chain variable domain has the CDRs of SEQ ID NO: 182. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 1-3, and the light chain variable domain has CDRs of SEQ ID NOS: 4-6. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 7-9, and the light chain variable domain has CDRs of SEQ ID NOS: 10-12. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 13- 15, and the light chain variable domain has CDRs of SEQ ID NOS: 16-18. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 19-21, and the light chain variable domain has CDRs of SEQ ID NOS: 22-24. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 25-27, and the light chain variable domain has CDRs of SEQ ID NOS: 28-30. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence DY and SEQ ID NOS: 152-153, and the light chain variable domain has CDRs of the amino acid sequence STE and SEQ ID NOS: 155-156.

[0087] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 201. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chainvariable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 202. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 201; and the light chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 202. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 201 and the light chain variable domain has the CDRs of SEQ ID NO: 202. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 1-3, and the light chain variable domain has CDRs of SEQ ID NOS: 4-6. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 7-9, and the light chain variable domain has CDRs of SEQ ID NOS: 10-12. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 13-15, and the light chain variable domain has CDRs of SEQ ID NOS: 16-18. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 19-21, and the light chain variable domain has CDRs of SEQ ID NOS: 22-24. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 25-27, and the light chain variable domain has CDRs of SEQ ID NOS: 28-30 In some embodiments, the heavy chain variable domain has CDRs of the amino acidsequence DY and SEQ ID NOS: 152-153, and the light chain variable domain has CDRs of the amino acid sequence STE and SEQ ID NOS: 155-156.

[0088] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO:614. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO:615. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 614; and thelight chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 615. In certain embodiments, the heavy chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 614; and the light chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 615. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 201 and the light chain variable domain has the CDRs of SEQ ID NO: 202. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 1-3, and the light chain variable domain has CDRs of SEQ ID NOS: 4-6. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 7-9, and the light chain variable domain has CDRs of SEQ ID NOS: 10-12. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 13-15, and the light chain variable domain has CDRs of SEQ ID NOS: 16-18. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 19-21, and the light chain variable domain has CDRs of SEQ ID NOS: 22-24. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 25- 27, and the light chain variable domain has CDRs of SEQ ID NOS: 28-30. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence DY and SEQ ID NOS: 152-153, and the light chain variable domain has CDRs of the amino acid sequence STE and SEQ ID NOS: 155-156.

[0089] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 31; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 32; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 33; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 34; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 35; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 36;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 37; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 38; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 39; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 40; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 41; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 42;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 43; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 44; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 45; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 46; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 47; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 48;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 49; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 50; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 51; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 52; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 53; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 54;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 55; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 56; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 57; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 58; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 59; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 60; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of GY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 158; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 159; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 161; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 162.

[0090] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 183; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 184. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 183 and the light chain variable domain has the CDRs of SEQ ID NO: 184. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 31-33, and the light chain variable domain has CDRs of SEQ ID NOS: 34-36. In some embodiments, the heavy chain variabledomain has CDRs of SEQ ID NOS: 37-39, and the light chain variable domain has CDRs of SEQ ID NOS: 40-42. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 43-45, and the light chain variable domain has CDRs of SEQ ID NOS: 46-48. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 49-51, and the light chain variable domain has CDRs of SEQ ID NOS: 52-54. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 55-57, and the light chain variable domain has CDRs of SEQ ID NOS: 58-60. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence GY and SEQ ID NOS: 158-159, and the light chain variable domain has CDRs of the amino acid sequence SY and SEQ ID NOS: 161-162.

[0091] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 203. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments,the heavy chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 204. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 203; and the light chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 204. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 203 and the light chain variable domain has the CDRs of SEQ ID NO: 204. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 31-33, and the light chain variable domain has CDRs of SEQ ID NOS: 34-36. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 37-39, and the light chain variable domain has CDRs of SEQ ID NOS: 40-42. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 43- 45, and the light chain variable domain has CDRs of SEQ ID NOS: 46-48. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 49-51, and the light chain variable domain has CDRs of SEQ ID NOS: 52-54. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 55-57, and the light chain variable domain has CDRs of SEQ ID NOS: 58-60. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence GY and SEQ ID NOS: 158-159, and the light chain variable domain has CDRs of the amino acid sequence SY and SEQ ID NOS: 161-162.

[0092] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO:616. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO:617. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 617. In certain embodiments, the heavy chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 616; and the light chain has at least about or about 99% sequenceidentity to the amino acid sequence of SEQ ID NO: 617. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 203 and the light chain variable domain has the CDRs of SEQ ID NO: 204. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 31-33, and the light chain variable domain has CDRs of SEQ ID NOS: 34-36. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 37-39, and the light chain variable domain has CDRs of SEQ ID NOS: 40-42. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 43-45, and the light chain variable domain has CDRs of SEQ ID NOS: 46-48. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 49-51, and the light chain variable domain has CDRs of SEQ ID NOS: 52-54. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 55-57, and the light chain variable domain has CDRs of SEQ ID NOS: 58-60. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence GY and SEQ ID NOS: 158-159, and the light chain variable domain has CDRs of the amino acid sequence SY and SEQ ID NOS: 161-162.

[0093] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 64; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 65; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 66;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 68; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 76; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 77; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 78;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 82; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 83; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 84;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 88; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 89; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 90; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 163; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 164; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 165; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 166; a CDRL2 comprising the amino acid sequence of EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 168.

[0094] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 185; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 186. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 185 and the light chain variable domain has the CDRs of SEQ ID NO: 186. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of SEQ ID NOS: 64-66. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67-69, and the light chain variable domain has CDRs of SEQ ID NOS: 70-72. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73- 75, and the light chain variable domain has CDRs of SEQ ID NOS: 76-78. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 82-84. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domainhas CDRs of SEQ ID NOS: 88-90. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 163-165, and the light chain variable domain has CDRs of the amino acid sequence EIS and SEQ ID NOS: 166 and 168.

[0095] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 205. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about orabout 96% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 206. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 206. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 205 and the light chain variable domain has the CDRs of SEQ ID NO: 206. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of SEQ ID NOS: 64-66. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67-69, and the light chain variable domain has CDRs of SEQ ID NOS: 70-72. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 76-78. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79- 81, and the light chain variable domain has CDRs of SEQ ID NOS: 82-84. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 88-90. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 163-165, and the light chain variable domain has CDRs of the amino acid sequence EIS and SEQ ID NOS: 166 and 168.

[0096] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 618. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence ofSEQ ID NO: 618; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 619. In certain embodiments, the heavy chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 619. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 205 and the light chain variable domain has the CDRs of SEQ ID NO: 206. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of SEQ ID NOS: 64-66. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67-69, and the light chain variable domain has CDRs of SEQ ID NOS: 70-72. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variabledomain has CDRs of SEQ ID NOS: 76-78. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 82-84. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 88-90. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 163-165, and the light chain variable domain has CDRs of the amino acid sequence EIS and SEQ ID NOS: 166 and 168.

[0097] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 91; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 92; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 93; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 94; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 95; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 96;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 97; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 98; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 99; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 100; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 101; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 102;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 103; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 104; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 105; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 106; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 107; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 108;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 109; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 110; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 111; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO:112; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 113; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 114;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 115; a CDRH2 comprising the amino acid sequence of SEQ ID NO:116; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 117; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 118; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 119; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 120; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of NY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 170; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 171; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of NSY; a CDRL2 comprising the amino acid sequence of RAN; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 174.

[0098] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 187; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 188. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 187 and the light chain variable domain has the CDRs of SEQ ID NO: 188. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 91-93, and the light chain variable domain has CDRs of SEQ ID NOS: 94-96. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 97-99, and the light chain variable domain has CDRs of SEQ ID NOS: 100-102. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 103-105, and the light chain variable domain has CDRs of SEQ ID NOS: 106-108. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 109-111, and the light chain variable domain has CDRs of SEQ ID NOS: 112-114. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 115-117, and the light chain variable domain has CDRs of SEQ ID NOS: 118-120. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence NY and SEQ ID NOS: 170-171, and the light chain variable domain has CDRs of the amino acid sequence NSY, RAN and SEQ ID NOS: 174.

[0099] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO:207. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chainvariable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 208. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 207; and the light chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 208. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 207 and the light chain variable domain has the CDRs of SEQ ID NO: 208. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 91-93, and the light chain variable domain has CDRs of SEQ ID NOS: 94-96. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 97-99, and the light chain variable domain has CDRs of SEQ ID NOS: 100-102. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 103-105, and the light chain variable domain has CDRs of SEQ ID NOS: 106-108. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 109-111, and the light chain variable domain has CDRs of SEQ ID NOS: 112-114. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 115-117, and the light chain variable domain has CDRs of SEQ ID NOS: 118-120. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence NY and SEQ ID NOS: 170- 171, and the light chain variable domain has CDRs of the amino acid sequence NSY, RAN and SEQ ID NOS: 174.

[0100] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 620. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about orabout 91% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 621. In certain embodiments, the heavy chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 620; and the light chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 621. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 207 and the light chain variable domain has the CDRs of SEQ ID NO: 208. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 91-93, and the light chain variable domain has CDRs of SEQ ID NOS: 94-96. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 97-99, and the light chain variable domain has CDRs of SEQ ID NOS: 100-102. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 103-105, and the light chain variable domain has CDRs of SEQ ID NOS: 106-108. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 109-111, and the light chain variable domain has CDRs of SEQ ID NOS: 112-114. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 115-117, and the light chain variable domain has CDRs of SEQ ID NOS: 118- 120. In some embodiments, the heavy chain variable domain has CDRs of the amino acidsequence NY and SEQ ID NOS: 170-171, and the light chain variable domain has CDRs of the amino acid sequence NS Y, RAN and SEQ ID NOS: 174.

[0101] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 121; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 122; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 123; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 124; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 125; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 126;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 127; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 128; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 129; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 130; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 131; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 132;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 133; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 134; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 135; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 136; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 137; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 138;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 139; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 140; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 141; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 142; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 143; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 144;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 145; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 146; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 147; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 148; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 149; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 150; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 176; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 177; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SKY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 179; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 180.

[0102] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 189; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 190. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 189 and the light chain variable domain has the CDRs of SEQ ID NO: 190. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 121-123, and the light chain variable domain has CDRs of SEQ ID NOS: 124-126. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 127-129, and the light chain variable domain has CDRs of SEQ ID NOS: 130-132. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 133-135, and the light chain variable domain has CDRs of SEQ ID NOS: 136-138. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 139-141, and the light chain variable domain has CDRs of SEQ ID NOS: 142-144. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 145-147, and the light chain variable domain has CDRs of SEQ ID NOS: 148-150. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence DY and SEQ ID NOS: 176- 177, and the light chain variable domain has CDRs of the amino acid sequence SKY and SEQ ID NOS: 179-180.

[0103] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 209. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least aboutor about 80% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 210. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 209; and the light chain variable domain hasat least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 210. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 209 and the light chain variable domain has the CDRs of SEQ ID NO: 210. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 121-123, and the light chain variable domain has CDRs of SEQ ID NOS: 124-126. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 127-129, and the light chain variable domain has CDRs of SEQ ID NOS: 130-132. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 133-135, and the light chain variable domain has CDRs of SEQ ID NOS: 136-138. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 139-141, and the light chain variable domain has CDRs of SEQ ID NOS: 142-144. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 145-147, and the light chain variable domain has CDRs of SEQ ID NOS: 148-150. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence DY and SEQ ID NOS: 176-177, and the light chain variable domain has CDRs of the amino acid sequence SKY and SEQ ID NOS: 179-180.

[0104] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 622. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavychain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 623. In certain embodiments, the heavy chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 622; and the light chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 623. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 209 and the light chain variable domain has the CDRs of SEQ ID NO: 210. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 121-123, and the light chain variable domain has CDRs of SEQ ID NOS: 124- 126. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 127- 129, and the light chain variable domain has CDRs of SEQ ID NOS: 130-132. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 133-135, and the light chain variable domain has CDRs of SEQ ID NOS: 136-138. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 139-141, and the light chain variable domain has CDRs of SEQ ID NOS: 142-144. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 145-147, and the light chain variable domain has CDRs of SEQ ID NOS: 148-150. In some embodiments, the heavy chain variable domain has CDRs of the amino acid sequence DY and SEQ ID NOS: 176-177, and the light chain variable domain has CDRs of the amino acid sequence SKY and SEQ ID NOS: 179-180.

[0105] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

[0106] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 185; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%,83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 624. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 185 and the light chain variable domain has the CDRs of SEQ ID NO: 624. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 642 and 644. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67-69, and the light chain variable domain has CDRs of SEQ ID NOS: 645-647. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 648-650. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653.

[0107] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 205. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence ofSEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 205; and the light chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 674. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 205 and the light chain variable domain has the CDRs of SEQ ID NO: 674. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 642 and 644. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67-69, and the light chain variable domain has CDRs of SEQ ID NOS: 645-647. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 648-650. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653.

[0108] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%,96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 618. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 618; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 99% sequence identity to the aminoacid sequence of SEQ ID NO: 618; and the light chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 624. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 205 and the light chain variable domain has the CDRs of SEQ ID NO: 624. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 642 and 644. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67-69, and the light chain variable domain has CDRs of SEQ ID NOS: 645-647. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 648-650. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653.

[0109] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 657; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 661; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 662; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 663;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80;a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672.

[0110] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 626. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 625 and the light chain variable domain has the CDRs of SEQ ID NO: 626. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 658 and 660. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67, 657, and 69, and the light chain variable domain has CDRs of SEQ ID NOS: 661-663. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 664-666. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 667-669. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 670-672.[OHl] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 675. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ IDNO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 675; and the light chainvariable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 676. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 675 and the light chain variable domain has the CDRs of SEQ ID NO: 676. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 658 and 660. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67, 657, and 69, and the light chain variable domain has CDRs of SEQ ID NOS: 661-663. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 664-666. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 667-669. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 670-672.

[0112] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 625. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chainhas at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 625; and the light chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 626. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 205 and the light chain variable domain has the CDRs of SEQ ID NO: 626. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 658 and 660. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67, 657, and 69, and the light chain variable domain has CDRs of SEQ ID NOS: 661-663. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 664-666. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 667-669. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 670-672.

[0113] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; aCDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

[0114] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 624. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 627 and the light chain variable domain has the CDRs of SEQ ID NO: 624. In some embodiments, the heavychain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 642 and 644. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67, 673, and 69, and the light chain variable domain has CDRs of SEQ ID NOS: 645-647. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 648-650. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653.

[0115] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 677. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about orabout 94% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 674. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 674. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 677 and the light chain variable domain has the CDRs of SEQ ID NO: 674. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 642 and 644. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67, 673, and 69, and the light chain variable domain has CDRs of SEQ ID NOS: 645-647. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 648-650. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653.

[0116] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 627. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 624. In certain embodiments, the heavy chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 624. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 205 and the light chain variable domain has the CDRs of SEQ ID NO:624. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 642 and 644. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67, 673, and 69, and the light chain variable domain has CDRs of SEQ ID NOS: 645-647. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 648-650. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 651-653. In some embodiments, the light chain variable domain has the CDRs of SEQ ID NO: 689. In some embodiments, provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb or FGFR3-IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 690; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 691. In some embodiments, provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb or FGFR3-IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 690; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 692. In some embodiments, provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb or FGFR3- IIIc, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 690; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 693.

[0117] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 661; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 662; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 663;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672.

[0118] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%,83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 626. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 627 and the light chain variable domain has the CDRs of SEQ ID NO: 626. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 658 and 660. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67, 673, and 69, and the light chain variable domain has CDRs of SEQ ID NOS: 661-663. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 664-666. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 667-669. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 670-672.

[0119] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 677. In certain embodiments, the light chain variable domain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 92% sequence identity to the amino acid sequence ofSEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 676. In certain embodiments, the heavy chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 677; and the light chain variable domain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 676. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 677 and the light chain variable domain has the CDRs of SEQ ID NO: 676. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 61-63, and the light chain variable domain has CDRs of amino acid sequence EIS and SEQ ID NOS: 658 and 660. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 67, 673, and 69, and the light chain variable domain has CDRs of SEQ ID NOS: 661-663. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 73-75, and the light chain variable domain has CDRs of SEQ ID NOS: 664-666. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 79-81, and the light chain variable domain has CDRs of SEQ ID NOS: 667-669. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 85-87, and the light chain variable domain has CDRs of SEQ ID NOS: 670-672.

[0120] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain has at least about or about 70%, 75%, 80%, 81%, 82%,83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 627. In certain embodiments, the light chain has at least about or about 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 80% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 85% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 90% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 91% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 92% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 93% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 94% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 95% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 96% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 97% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavy chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 98% sequence identity to the amino acid sequence of SEQ ID NO: 626. In certain embodiments, the heavychain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 627; and the light chain has at least about or about 99% sequence identity to the amino acid sequence of SEQ ID NO: 626. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 205 and the light chain variable domain has the CDRs of SEQ ID NO: 626.

[0121] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 211; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 212; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 213; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 214; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 215; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 216;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 217; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 218; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 219; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 220; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 221; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 222;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 223; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 224; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 225; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 226; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 227; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 228;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 229; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 230; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 231; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 232; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 233; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 234;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 235; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 236; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 237; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO:238; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 239; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 240;(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 241; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 242; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 243; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 244; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 245; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 246;(vii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 247; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 248; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 249; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 250; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 251; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 252;(viii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 253; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 254; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 255; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 256; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 257; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 258;(ix) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 259; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 260; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 261; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 262; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 263; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 264;(x) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 265; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 266; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 267; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 268; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 269; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 270;(xi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 271; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 272; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 273; and a light chainvariable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 274; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 275; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 276;(xii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 277; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 278; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 279; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 280; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 281; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 282;(xiii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 283; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 284; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 285; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 286; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 287; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 288;(xiv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 289; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 290; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 291; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 292; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 293; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 294;(xv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 295; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 296; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 297; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 298; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 299; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 300;(xvi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 301; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 302; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 303; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 304; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 305; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 306; or(xvii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 307; a CDRH2 comprising the amino acid sequence of SEQ ID NO:308; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 309; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 310; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 311; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 312.

[0122] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 511; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 512. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 511 and the light chain variable domain has the CDRs of SEQ ID NO: 512. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 211- 213, and the light chain variable domain has CDRs of SEQ ID NOS: 214-216.

[0123] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 513; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 514. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 513, and the light chain variable domain has the CDRs of SEQ ID NO: 514. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 217- 219, and the light chain variable domain has CDRs of SEQ ID NOS: 220-222.

[0124] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 515; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 516. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 515, and the light chain variable domain has the CDRs of SEQ ID NO: 516. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 223- 225, and the light chain variable domain has CDRs of SEQ ID NOS: 226-228.

[0125] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 517; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 518. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 517, and the light chain variable domain has the CDRs of SEQ ID NO: 518. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 229- 231, and the light chain variable domain has CDRs of SEQ ID NOS: 232-234.

[0126] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 519; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 520. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 519, and the light chain variable domain has the CDRs of SEQ ID NO: 520. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 235- 237, and the light chain variable domain has CDRs of SEQ ID NOS: 238-240.

[0127] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 521; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 522. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 521, and the light chain variable domain has the CDRs of SEQ ID NO: 522. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 241- 243, and the light chain variable domain has CDRs of SEQ ID NOS: 244-246.

[0128] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 523; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 524. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 523, and the light chain variable domain has the CDRs of SEQ ID NO: 524. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 247- 249, and the light chain variable domain has CDRs of SEQ ID NOS: 250-252.

[0129] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 525; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 526. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 525, and the light chain variable domain has the CDRs of SEQ ID NO: 526. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 253- 255, and the light chain variable domain has CDRs of SEQ ID NOS: 256-258.

[0130] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 527; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 528. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 527, and the light chain variable domain has the CDRs of SEQ ID NO: 528. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 259- 261, and the light chain variable domain has CDRs of SEQ ID NOS: 262-264.

[0131] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 529; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 530. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 529, and the light chain variable domain has the CDRs of SEQ ID NO: 530. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 265- 267, and the light chain variable domain has CDRs of SEQ ID NOS: 268-270.

[0132] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 531; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 532. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 531, and the light chain variable domain has the CDRs of SEQ ID NO: 532. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 271- 273, and the light chain variable domain has CDRs of SEQ ID NOS: 274-276.

[0133] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 533; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 534. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 533, and the light chain variable domain has the CDRs of SEQ ID NO: 534. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 277- 279, and the light chain variable domain has CDRs of SEQ ID NOS: 280-282.

[0134] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 535; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 536. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 535, and the light chain variable domain has the CDRs of SEQ ID NO: 536. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 283- 285, and the light chain variable domain has CDRs of SEQ ID NOS: 286-288.

[0135] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 537; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 538. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 537, and the light chain variable domain has the CDRs of SEQ ID NO: 538. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 289- 291, and the light chain variable domain has CDRs of SEQ ID NOS: 292-294.

[0136] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 539; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 540. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 539, and the light chain variable domain has the CDRs of SEQ ID NO: 540. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 295- 297, and the light chain variable domain has CDRs of SEQ ID NOS: 298-300.

[0137] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 541; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 542. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 541, and the light chain variable domain has the CDRs of SEQ ID NO: 542. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 301- 303, and the light chain variable domain has CDRs of SEQ ID NOS: 304-306.

[0138] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb and FGFR3-IIIc, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 543; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 544. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 543, and the light chain variable domain has the CDRs of SEQ ID NO: 544. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 307- 309, and the light chain variable domain has CDRs of SEQ ID NOS: 310-312.

[0139] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 313; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 314; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 315; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO:316; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 317; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 318;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 319; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 320; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 321; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 322; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 323; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 324;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 325; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 326; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 327; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 328; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 329; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 330;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 331; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 332; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 333; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 334; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 335; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 336;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 337; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 338; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 339; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 340; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 341; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 342;(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 343; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 344; a CDRH3 comprising the amino acid sequence of DDY; and a light chain variable domaincomprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 346; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 347; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 348;(vii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 349; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 350; a CDRH3 comprising the amino acid sequence of TTH; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 352; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 353; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 354;(viii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 355; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 356; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 357; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 358; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 359; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 360;(ix) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 361; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 362; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 363; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 364; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 365; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 366;(x) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 367; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 368; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 369; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 370; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 371; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 372;(xi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 373; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 374; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 375; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 376; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 377; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 378;(xii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 379; a CDRH2 comprising the amino acid sequence of SEQ ID NO:380; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 381; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 382; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 383; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 384;(xiii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 385; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 386; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 387; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 388; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 389; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 390;(xiv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 391; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 392; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 393; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 394; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 395; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 396;(xv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 397; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 398; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 399; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 400; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 401; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 402;(xvi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 403; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 404; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 405; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 406; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 407; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 408;(xvii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 409; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 410; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 411; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 412; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 413; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 414;(xviii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 415; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 416; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 417; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 418; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 419; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 420;(xix) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 421; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 422; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 423; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 424; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 425; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 426;(xx) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 427; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 428; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 429; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 430; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 431; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 432;(xxi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 433; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 434; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 435; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 436; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 437; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 438;(xxii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 439; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 440; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 441; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 442; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 443; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 444;(xxiii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 445; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 446; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 447; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO:448; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 449; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 450;(xxiv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 451; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 452; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 453; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 454; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 455; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 456;(xxv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 457; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 458; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 459; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 460; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 461; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 462;(xxvi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 463; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 464; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 465; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 466; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 467; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 468;(xxvii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 469; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 470; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 471; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 472; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 473; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 474;(xxviii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 475; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 476; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 477; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 478; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 479; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 480;(xxix) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 481; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 482; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 483; and a light chainvariable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 484; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 485; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 486;(xxx) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 487; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 488; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 489; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 490; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 491; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 492;(xxxi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 493; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 494; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 495; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 496; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 497; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 498;(xxxii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 499; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 500; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 501; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 502; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 503; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 504; or(xxxiii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 505; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 506; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 507; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 508; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 509; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 510.

[0140] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 545; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 546. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 545, and the light chain variable domain has the CDRs of SEQ ID NO: 546. In someembodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 313-315, and the light chain variable domain has CDRs of SEQ ID NOS: 316-318.

[0141] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 547; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 548. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 547, and the light chain variable domain has the CDRs of SEQ ID NO: 548. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 319-321, and the light chain variable domain has CDRs of SEQ ID NOS: 322-324.

[0142] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 549; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 550. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 549, and the light chain variable domain has the CDRs of SEQ ID NO: 550. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 325-327, and the light chain variable domain has CDRs of SEQ ID NOS: 328-330.

[0143] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 551; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 552. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 551, and the light chain variable domain has the CDRs of SEQ ID NO: 552. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 331-333, and the light chain variable domain has CDRs of SEQ ID NOS: 334-336.

[0144] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%sequence identity to the amino acid sequence of SEQ ID NO: 553; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 554. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 553, and the light chain variable domain has the CDRs of SEQ ID NO: 554. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 337-339, and the light chain variable domain has CDRs of SEQ ID NOS: 340-342.

[0145] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 555; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 556. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 555, and the light chain variable domain has the CDRs of SEQ ID NO: 556. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 343-344 and the amino acid sequence DDY, and the light chain variable domain has CDRs of SEQ ID NOS: 346- 348.

[0146] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 557; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 558. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 557, and the light chain variable domain has the CDRs of SEQ ID NO: 558. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 349-350 and the amino acid sequence TTH, and the light chain variable domain has CDRs of SEQ ID NOS: 352- 354.

[0147] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 559; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQID NO: 560. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 559, and the light chain variable domain has the CDRs of SEQ ID NO: 560. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 355-357, and the light chain variable domain has CDRs of SEQ ID NOS: 358-360.

[0148] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 561; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 562. In some embodiments, the heavy chain variable domain has the CDRs of SEQ ID NO: 561, and the light chain variable domain has the CDRs of SEQ ID NO: 562. In some embodiments, the heavy chain variable domain has CDRs of SEQ ID NOS: 361-363, and the light chain variable domain has CDRs of SEQ ID NOS: 364-366.

[0149] Provided and exemplified herein are antibodies and / or antibody fragments that bind FGFR3-IIIb, wherein the heavy chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 563; and the light chain variable domain has 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to the amino acid sequence of SEQ ID NO: 564. In some embodiments, t...

Claims

CLAIMSWhat is claimed is:

1. An antibody or antibody fragment that binds FGFR-IIIb comprising:(i) a heavy chain variable domain comprising: a heavy chain complementarity determining region 1 (CDRH1) comprising the amino acid sequence of SEQ ID NO: 67; a heavy chain complementarity determining region 2 (CDRH2) comprising the amino acid sequence of SEQ ID NO: 673; a heavy chain complementarity determining region 3 (CDRH3) comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a light chain complementarity determining region 1 (CDRL1) comprising the amino acid sequence of SEQ ID NO: 661; a light chain complementarity determining region 2 (CDRL2) comprising the amino acid sequence of SEQ ID NO: 662; and a light chain complementarity determining region 3 (CDRL3) comprising the amino acid sequence of SEQ ID NO: 663;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 689; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; aCDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666;(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669;(vii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672;(viii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 64; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 65; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 66;(ix) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 68; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 70; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 71; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 72;(x) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 76; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 77; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 78;(xi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variabledomain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 82; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 83; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 84;(xii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 88; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 89; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 90;(xiii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 163; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 164; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 165; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 166; a CDRL2 comprising the amino acid sequence of EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 168; a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 91; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 92; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 93; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 94; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 95; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 96;(xiv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 97; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 98; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 99; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 100; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 101; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 102;(xv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 103; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 104; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 105; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 106; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 107; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 108;(xvi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 109; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 110; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 111; and a light chainvariable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 112; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 113; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 114;(xvii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 115; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 116; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 117; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 118; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 119; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 120; or(xviii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of NY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 170; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 171; and a light chain variable domain comprising: a light chain complementarity determining region 1 (CDRL1 comprising the amino acid sequence of NSY; a CDRL2 comprising the amino acid sequence of RAN; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 174.

2. An antibody or antibody fragment that binds FGFR3-IIIb and FGFR3-IIIc comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 1; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 2; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 3; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 4; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 5; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 6;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 7; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 8; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 9; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 10; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 11; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 12;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 13; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 14; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 15; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 16; a CDRL2 comprising the amino acidsequence of SEQ ID NO: 17; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 18;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 19; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 20; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 21; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 22; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 23; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 24;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 25; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 26; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 27; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 28; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 29; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 30; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 152; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 153; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of STE; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 155; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 156.

3. An antibody or antibody fragment that binds FGFR3-IIIb and FGFR3-IIIc comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 31; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 32; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 33; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 34; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 35; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 36;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 37; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 38; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 39; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 40; a CDRL2 comprising the amino acidsequence of SEQ ID NO: 41; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 42;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 43; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 44; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 45; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 46; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 47; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 48;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 49; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 50; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 51; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 52; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 53; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 54;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 55; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 56; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 57; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 58; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 59; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 60; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of GY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 158; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 159; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 161; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 162.

4. An antibody or antibody fragment that binds FGFR3-IIIb and FGFR3-IIIc comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 121; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 122; and a CDRH3 comprising the amino acid sequence of SEQ ID NO: 123; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 124; a CDRL2 comprising the amino acidsequence of SEQ ID NO: 125; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 126;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 127; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 128; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 129; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 130; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 131; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 132;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 133; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 134; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 135; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 136; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 137; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 138;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 139; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 140; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 141; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 142; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 143; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 144;(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 145; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 146; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 147; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 148; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 149; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 150; or(vi) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of DY; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 176; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 177; and a light chain variable domain comprising: a CDRL1 comprising the amino acidsequence of SKY; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 179; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 180.

5. An antibody or antibody fragment that binds FGFR3-IIIb comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising theamino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

6. An antibody or antibody fragment that binds FGFR3-IIIb comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 658; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 660;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 657; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 661; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 662; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 663;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 664; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 665; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 666;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 667; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 668; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 669; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO:87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 670; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 671; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 672.

7. An antibody or antibody fragment that binds FGFR3-IIIb comprising:(i) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 61; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 62; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 63; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 642; a CDRL2 comprising the amino acid sequence EIS; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 644;(ii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 67; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 673; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 69; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 645; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 646; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 647;(iii) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 73; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 74; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 75; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 648; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 649; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 650;(iv) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 79; a CDRH2 comprising the amino acid sequence of SEQ ID NO: 80; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 81; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 651; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 652; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 653; or(v) a heavy chain variable domain comprising: a CDRH1 comprising the amino acid sequence of SEQ ID NO: 85; a CDRH2 comprising the amino acid sequence ofSEQ ID NO: 86; a CDRH3 comprising the amino acid sequence of SEQ ID NO: 87; and a light chain variable domain comprising: a CDRL1 comprising the amino acid sequence of SEQ ID NO: 654; a CDRL2 comprising the amino acid sequence of SEQ ID NO: 655; and a CDRL3 comprising the amino acid sequence of SEQ ID NO: 656.

8. An antibody or antibody fragment that binds FGFR3-IIIb comprising a heavy chain variable region and a light chain variable region, wherein: the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 677, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 676; the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 683, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 206; the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 677, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 206; or the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 684, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 682.

9. An antibody or antibody fragment that binds FGFR3-IIIb and FGFR3-IIIc comprising a heavy chain variable region and a light chain variable region, wherein: the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 209, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 210; or the CDRs of the heavy chain variable region are the CDRs of SEQ ID NO: 201, and the CDRs of the light chain variable region are the CDRs of SEQ ID NO: 202.

10. An antibody or antibody fragment that binds FGFR3-IIIb comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the heavy chain variable region and the CDRs of the light chain variable region comprise SEQ ID NOS: 1-3, 4-6; 7-9, 10-12; 13-15, 16-18; 19-21, 22-24; 25-27, 28-30; 31-33, 34-36; 37-39, 40- 42; 43-45, 46-48; 49-51, 52-54; 55-57, 58-60; 61-63, 64-66; 67-69, 70-72; 73-75, 76-78; 79-81, 82-84; 85-87, 88-90; 91-93, 94-96; 97-99, 100-102; 103-105, 106-108; 109-111, 112-114; 115-117, 118-120; 121-123, 124-126; 127-129, 130-132; 133-135, 136-138; 139-141, 142-144; 145-147, 148-150; DY, 152-153, STE, 155-156; GY, 158-159, SY, 161-162; 163-165, 166, EIS, 168; NY, 170-171, NSY, RAN, 174; DY, 176-177, SKY, 179-180; 211-213, 214-216; 217-219, 220-222; 223-225, 226-228; 229-231, 232-234; 235-237, 238-240; 241-243, 244-246; 247-249, 250-252; 253-255, 256-258; 259-261, 262-264; 265-267, 268-270; 271-273, 274-276; 277-279, 280-282; 283-285, 286-288; 289-291, 292, 294; 295-297, 298-300; 301-303, 304-306; 307-309, 310-312; 313-315, 316-318; 319-321, 322-324; 325-327, 328-330; 331-333, 334-336; 337-339, 340-342;343-344, DDY, 346-348; 349-350, TTH, 352-354; 355-357, 358-360; 361-363, 364-366; 367-369, 370-372; 373-375, 376-378; 379-381, 382-384; 385-387, 388-390; 391-393, 394-396; 397-399, 400-402; 403-405, 406-408; 409-411, 412-414; 415-417, 418-420; 421-423, 424-426; 427-429, 430-432; 433-435, 436-438; 439-441, 442-444; 445-447, 448-450; 451-453, 454-456; 457-459, 460-462; 463-465, 466-468; 469-471, 472-474; 475-477, 478-480; 481-483, 484-486; 487-489, 490-492; 493-495, 496-498; 499-501, 502-504; or 505-507, 508-510; respectively.

11. An antibody or antibody fragment that binds FGFR3-IIIb and FGFR3-IIIc comprising a heavy chain variable region and a light chain variable region, wherein the CDRs of the heavy chain variable region and the CDRs of the light chain variable region comprise SEQ ID NOS: 1-3, 4-6; 7-9, 10-12; 13-15, 16-18; 19-21, 22-24; 25-27, 28-30; 31-33, 34- 36; 37-39, 40-42; 43-45, 46-48; 49-51, 52-54; 55-57, 58-60; 121-123, 124-126; 127-129, 130-132; 133-135, 136-138; 139-141, 142-144; 145-147, 148-150; DY, 152-153, STE, 155-156; DY, 158-159, SY, 161-162; DY, 176-177, SKY, 179-180; 211-213, 214-216; 217-219, 220-222; 223-225, 226-228; 229-231, 232-234; 235-237, 238-240; 241-243, 244-246; 247-249, 250-252; 253-255, 256-258; 259-261, 262-264; 265-267, 268-270; 271-273, 274-276; 277-279, 280-282; 283-285, 286-288; 289-291, 292, 294; 295-297, 298-300; 301-303, 304-306; 307-309, or 310-312; respectively.

12. The antibody or antibody fragment of any one of claims 1-11, wherein the antibody or antibody fragment comprises:(i) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 676;(ii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 683 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206;(iii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206;(iv) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ IDNO: 684 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 682;(v) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 202;(vi) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 203 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 204;(vii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 205 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206;(viii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 207 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 208; or(ix) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

13. An antibody or antibody fragment that binds FGFR3-IIIb comprising:(i) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 676;(ii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 683 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206;(iii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 677 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206;(iv) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 684 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 682;(v) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 202;(vi) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 203 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 204;(vii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 205 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206;(viii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 207 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 208; or(ix) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

14. An antibody or antibody fragment that binds FGFR3-IIIb and FGFR3-IIIc comprising:(i) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ IDNO: 201 and a light chain variable region (VL) having at least 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 202;(ii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 205 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 206;(iii) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 207 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 208; or(iv) a heavy chain variable region (VH) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 209 and a light chain variable region (VL) having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NO: 210.

15. The antibody or antibody fragment of any one of claims 1-14, wherein the antibody or antibody fragment comprises an Fc domain.

16. The antibody or antibody fragment of any one of claims 1-14, wherein the antibody or antibody fragment that binds FGFR3-IIIb comprises:(i) a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 614 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 615;(ii) a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 616 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 617;(iii)a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 618 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 619;(iv)a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 620 and a light chainhaving at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 621; or(v) a heavy chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 622 and a light chain having at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ NO: 623.

17. The antibody or antibody fragment of any one of claims 1-16, wherein the antibody or antibody fragment does not bind with an affinity of about or less than about 10 X 10'8M to FGFR1, FGFR2, or FGFR4.

18. The antibody or antibody fragment of any one of claims 1-17, wherein the antibody or antibody fragment binds to a FGFR3-IIIb protein with an equilibrium dissociation constant (KD) equal to or less than 10 x 10'8M.

19. The antibody or antibody fragment of claim 18, wherein the FGFR3-IIIb protein comprises the amino acid sequence of SEQ ID NO: 191, 195, or 197.

20. The antibody or antibody fragment of any one of claims 1-19, wherein the antibody is internalized by a cell expressing FGFR3-IIIb.

21. The antibody or antibody fragment of claim 20, wherein the cell is a HEK-293 cell expressing FGFR3-IIIb.

22. A pharmaceutical composition comprising: an antibody and antibody fragment comprising means for binding FGFR3-IIIb; and a pharmaceutically acceptable carrier.

23. A pharmaceutical composition comprising: an antibody and antibody fragment comprising means for binding FGFR3-IIIb and internalizing into a cell expressing FGFR3-IIIb; and a pharmaceutically acceptable carrier.

24. A method of inhibiting proliferation of a cell expressing FGFR3-IIIb, the method comprising: contacting a cell with the antibody or antibody fragment of any one of claims 1-21 or the pharmaceutical composition of any one of claims 22-23.

25. The method of claim 24, wherein the antibody or antibody fragment is internalized by the cell.

26. The method of any one of claims 24-25, wherein the cell is a Ba / F3 cell expressing FGFR3-IIIb.

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