High efficacy of arsenic trioxide plus all-trans retinoic acid based induction and maintenance therapy in newly diagnosed acute promyelocytic leukemia.

We conducted a retrospective study to evaluate the efficacy of combining arsenic trioxide (ATO) with all-trans-retinoic acid (ATRA) based induction therapy, followed by 3 courses of consolidation chemotherapy and 2-year sequential ATO/ATRA maintenance therapy in acute promyelocytic leukemia (APL). 137 patients were enrolled in the study. The complete remission (CR) rate was 93.4%. All the 9 (6.6%) induction failures were due to early death. With a median follow-up of 35 months, 5 relapses (4%) in CR patients were recorded, including 3 isolated CNS relapses. By using the Kaplan-Meier analysis, the 5-year overall survival and relapse-free survival of the low/intermediate risk group and high-risk group was 98.9% versus 97.4% and 98.7% versus 87.9%, respectively. The results indicated that ATO based first-line protocol is highly effective for treatment of newly diagnosed APL.