596013 Disclosed is an immunoconjugate comprising a cytotoxic agent and a human or humanized antibody or functional fragment thereof comprising an antigen binding site that is specific for Mesothelin, wherein said antibody or functional fragment thereof exhibits invariant binding of Mesothelin and, wherein the antibody binding site includes a CDR 1, CDR 2 and CDR 3 wherein: a) said CDR 1 is selected from SEQ ID NO: 3 and 12 (GYSFTSYWIG, WMGIIDPGDSRTRYSPSFQG), b) said CDR 2 is selected from SEQ ID NO: 6 and 15 (GQLYGGTYMDG, TGTSSDIGGYNSVS), c) said CDR 3 is selected from SEQ ID NO: 9 and 19 (LMIYGVNNRPS, SSYDIESATP), and the cytotoxic agent consists of maytansinoid or a derivative thereof.
