Guanazole (NSC-1895)--a phase I clinical study.

Two dose schedules of guanazole were used in this phase I clinical study: intermittent prolonged 5-day infusion and intermittent iv bolus twice weekly. Ninety-seven treatment observations were analyzed for toxic effects resulting from the prolonged infusion and 42 from the twice-weekly bolus schedule. The main toxic effect was bone marrow suppressions, the frequency and severity of which were intensified by prior chemotherapy or radiotherapy and repetition of guanazole therapy. The leukocyte count was affected more than the platelet count. Partial responses were observed in four patients: two with lung carcinoma, one with prostate carcinoma, and one with melanoma. Further phase II clinical studies of guanazole are indicated.