5-fluorouracil and isoprinosine in the treatment of advanced colorectal cancer. A limited phase I, II evaluation

Abstract

We studied the effects of 5-fluorouracil (5-FU) and isoprinosine (ISO) on 15 patients with previously untreated metastatic colorectal carcinoma. The patients were treated in a limited Phase I, II protocol. All patients received a fixed ISO dose of 4 g orally on days 1 through 5 of each cycle. Each cycle was repeated every 35 days. The first seven patients were treated with an initial 5-FU dose of 7.5 mg/kg intravenously (IV) on days 1 through 5, which was escalated to 11.5 mg/kg IV after the first course and to 13 mg/kg IV after the second course. The next eight patients were treated with an initial 5-FU dose of 11.5 mg/kg IV on days 1 through 5, which was escalated to 13 mg/kg IV on days 1 through 5. No major responses (complete or partial) were documented. Median survival for all evaluable patients was 33 weeks. Toxicity was predominantly gastrointestinal and hematologic and was considered moderate. Our data suggest that 5-FU and ISO, at the doses used, were ineffectual in the treatment of metastatic colorectal carcinoma.