Phase II trial of diaziquone in patients with colon cancer

Seventeen patients with metastatic colon cancer received diaziquone iv daily for 5 days repeated every 28 days. Based on recommended starting doses for phase II trials (6-8 mg/m2 daily X 5), the first six patients received 7 mg/m2/day X 5. Two of these patients were heavily pretreated with chemotherapy, two had received prior 5-FU alone, and two had received no prior chemotherapy. There were no responses and three septic deaths (both of the heavily pretreated patients and one 5-FU-only patient who received concurrent radiotherapy). Eleven subsequent patients received 5.5 mg/m2/day X 5. Nine had no prior therapy; two had received prior 5-FU. No antitumor responses were observed. Myelosuppression was again the major toxic effect. No further septic deaths occurred. Diaziquone in this dose and schedule had no antitumor activity in this group of patients.