Phase II Clinical Trial of a Murine Monoclonal Antibody Cytotoxic for Gastrointestinal Adenocarcinoma

A murine monoclonal antibody (MAb) which binds to human metastatic gastrointestinal adenocarcinomas can be administered safely and has tumor effects in some patients. Its therapeutic effect was assessed in 20 patients with measurable advanced colorectal carcinoma that was refractory to prior surgical resection, chemotherapy, and/or radiotherapy. All patients had agreed to receive no other therapy at the time of MAb administration and follow-up evaluation. In one patient, tumor at all known sites responded after a single i.v. injection of antibody. One other patient had a marked reduction in a hepatic metastasis where binding of 131I-labeled F(ab')2 MAb fragments was demonstrated but not in his abdominal wall metastases where no MAb binding could be demonstrated. In a third patient, stabilization persisting for 12 mo of an aggressively growing tumor was observed. The antibody was well tolerated in all patients, although 10 patients mounted an anti-murine immunoglobulin antibody response.