Monoclonal antibodies specific for fibroblast growth factor receptor 4 (FGFR4) and methods of their use

An isolated monoclonal antibody that specifically binds fibroblast growth factor receptor 4 (FGFR4), or an antigen-binding fragment thereof, comprising a variable heavy (VH) domain and a variable light (VL) domain, wherein:

• the amino acid sequence of the VH domain of the antibody comprises the complementarity determining region 1 (CDR1), CDR2 and CDR3 sequences of SEQ ID NO:
• 3, wherein the CDR1, CDR2, and CDR3 sequences respectively comprise residues 26-33, 52-59, and 98-111 of SEQ ID NO:3;
• and
• the amino acid sequence of the VL domain of the antibody comprises the CDR1, CDR2 and CDR3 sequences of SEQ ID NO:
• 4, wherein the CDR1, CDR2, and CDR3 sequences respectively comprise residues 27-32, 50-52, and 88-98 of SEQ ID NO:4.