Antibody therapy

A composition comprising:

• a) a naked humanized MN-14 (hMN-14) antibody comprising light chain variable region CDR sequences CDR1 (KASQDVGTSVA, SEQ ID NO:
• 20);
• CDR2 (WTSTRHT, SEQ ID NO:
• 21);
• and CDR3 (QQYSLYRS, SEQ ID NO:
• 22);
• and heavy chain variable region CDR sequences CDR1 (TYWMS, SEQ ID NO:
• 23);
• CDR2 (EIHPDSSTINYAPSLKD, SEQ ID NO:
• 24);
• and CDR3 (LYFGFPWFAY, SEQ ID NO:
• 25) and human framework region sequences and an IgG1 human constant region, wherein administration of the naked hMN-14 antibody to a cancer expressing CEA sensitizes the cancer to administration of an apoptosis agent selected from the group consisting of DTIC and CPT-11;
• and
• b) an apoptosis agent selected from the group consisting of DTIC and CPT-11, wherein the combination of the naked hMN-14 antibody and the apoptosis agent is more effective for treatment of human medullary thyroid carcinoma or human colorectal cancer than either the naked anti-CEA MAb or the apoptosis agent alone or the sum of the effects of the naked anti-CEA MAb and the apoptosis agent administered individually.