Immunotherapy of gastrointestinal cancer with monoclonal antibodies.

Twenty patients with widespread metastatic colorectal carcinoma were infused with 500 mg of the cytotoxic IgG2a monoclonal antibody 17-1A preincubated with autologous peripheral blood leukocytes. Ten patients showed no benefit from such therapy and ten died, with a mean survival time of 7.6 +/- 4.5 months after treatment and a median survival of 6 months. In ten additional patients, the course of disease was modified by antibody therapy; disease in five of these patients stabilized, while tumor size in the other five patients decreased after therapy. Median actual survival in this group of ten patients is presently 24 months; four of these patients died of disease progression within a mean of 15 +/- 5 months. Duration of response was 10.5 +/- 6.7 months after antibody treatment. Treatment tolerance for these 20 patients was excellent in all but one patient, who experienced an anaphylactic reaction during a second infusion with 17-1A.