Phase II study of hexamethylmelamine for disseminated prostatic carcinoma.

Hexamethylmelamine (NSC-13875) was given to 15 patients with disseminated prostatic cancer in a daily x 21 schedule at 6-week intervals. The schedule was 320 mg/m2/day in four divided doses for good-risk patients and 240 mg/m2/day for poor-risk patients. No response was observed in 14 evaluable patients, but seven patients had stable disease. Limiting toxicity was nausea and vomiting which developed in 80% of the patients and it was the reason for discontinuation of therapy in one patient. Hematologic toxicity was acceptable, and occurred in 80% of the patients. Leukopenia was more frequent than thrombocytopenia, occurring in 80% and 20%, respectively. All patients had been previously treated with hormones, but 6/15 were never exposed to cytotoxic chemotherapy.