Phase II trial with chlorozotocin in advanced colorectal cancer

The single agent activity of chlorozotocin was evaluated in advanced colorectal cancer not previously treated with chemotherapy. The drug was given at a dosage of 200 mg/m 2 i.v. repeated every 6 wk . Of 23 evaluable patients, 2 achieved a partial response lasting 4 and 5 months respectively. With this dosage regimen, chlorozotocin produced essentially nausea and vomiting in one-half of the patients as well as myelosuppression that varied with performance status. Our findings suggest that the therapeutic index of chlorozotocin is similar to that of other conventional nitrosourea derivatives in this disease. However, additional experience is needed to definitely assess how cumulative is their respective bone marrow toxicity.