In a multicenter, phase II trial, CI-958, a benzothiopyranoindazole DNA intercalator, was administered to 18 patients who had not received prior chemotherapy for metastatic colorectal cancer. The drug was given by intravenous infusion at a dose of 700 mg/m2 every 21 days. There were no objective responses. Grades III and IV toxic effects were limited to granulocytopenia in 42% of courses and anemia in 5% of courses. There was one case of grade III increase in transaminases. Our results show that at this dose and schedule, CI-958 lacks activity against colorectal cancer.