Intermittent guanazole therapy in adult acute leukemia

Guanazole is a specific inhibitor of DNA synthesis. It has shown marked schedule dependency in the treatment of L1210 leukemia. In a Phase II study guanazole was given in an induction dose of 7.5 gm per square meter per day for 5 days by continuous intravenous infusion and repeated every 14 days. Twenty-four leukemic patients received an adequate trial (3 or more courses). There were 4 complete remissions, 2 partial remissions, 4 hematologic responses, and 34 failures. Complete remissions occurred in 3 patients with acute myelogenous leukemia lasting 49 days in 1, and 2 patients were still in complete remission 451 and 230 days after treatment. One patient with chronic myelogenous leukemic blast transformation achieved a complete remission lasting 99 days. Myelosuppression was the major toxic effect.