Abstract: A method for treatment of tumors to which antibody A5B7 binds is disclosed. A5B7 is a monoclonal antibody which binds to carcinoembryonic antigen. The method comprises administering to a host in need of such treatment an effective amount of a system which comprises a conjugate comprising: antibody A5B7 or a humanized version of A5B7 linked to an enzyme selected from the group consisting of carboxypeptidase G2 (CPG2), nitroreductase, a human enzyme, a non-human enzyme rendered non-immunogenic in man and a humanized catalytic antibody; and a prodrug convertible under the influence of the conjugate into a cytotoxic drug.

Abstract: A treatment for tumors to which antibody A5B7 binds is disclosed. A5B7 is a monoclonal antibody which binds to carcinoembryonic antigen. The treatment comprises administering to a host in need of such treatment an effective amount of a system which comprises: a conjugate comprising antibody A5B7 or a humanized version of A5B7 linked to an enzyme selected from the group consisting of carboxypeptidase G2 (CPG2), nitroreductase, a human enzyme, a non-human enzyme rendered non-immunogenic in man and a humanized catalytic antibody; and a prodrug convertible under the influence of the conjugate into a cytotoxic drug.