Phase II study of chlorozotocin in the treatment of advanced colorectal cancer.

In 39 patients with advanced colorectal cancer and no previous chemotherapy, treatment with chlorozotocin was associated with a 5% objective response rate and a median survival of 19 weeks. All of the responses occurred in patients with rectal tumors. Mild gastrointestinal symptoms affected 64% of the patients after treatment, but bone marrow suppression was not evident. Chlorozotocin is not effective against colorectal cancer when used as a single agent given as an iv bolus at doses of 120 mg/m2 (30 patients) and 150 mg/m2 (nine patients). However, further studies using a higher dose might be worthwhile.