Patent ID: 8017736

Claim:
An isolated humanized antibody or antigen-binding fragment thereof that competes for binding to alpha-fetoprotein (AFP) with a murine antibody comprising heavy chain complementarity determining region (CDR) sequences CDR1 (SYVIH, SEQ ID NO:4), CDR2 (YIHPYNGGTKYNEKFKG, SEQ ID NO:5) and CDR3 (SGGGDPFAY, SEQ ID NO:6) and light chain CDR sequences CDR1 (KASQDINKYIG, SEQ ID NO: 1), CDR2 (YTSALLP, SEQ ID NO:2) and CDR3 (LQYDDLWT, SEQ ID NO:3), said humanized antibody or fragment thereof comprising the framework (FR) regions of the light and heavy chain variable regions of a human antibody and the light and heavy chain constant regions of a human antibody, wherein the framework regions of said humanized antibody or fragment thereof comprise at least one amino acid substituted from the corresponding position(s) in the FRs of a parent murine anti-AFP antibody, selected from the group consisting of amino acid residues 5, 27, 28, 30, 46, 48, 66, 67 and 94 of SEQ ID NO:31 and amino acid residues 4, 39, 48, 49, 58, 69, 100 and 107 of SEQ ID NO:33.