Treatment of Relapsed Acute Promyelocytic Leukemia by Arsenic Trioxide in Iran

Background: Although standard first line treatment of acute promyelocytic leukemia is All trans retinoic acid (ATRA) and chemotherapy, some patients relapse and need a second line of treatment. Relapsed cases of promyelocytic leukemia can be salvaged with arsenic trioxide. Methods: Between May 1999 and Jan. 2010, we treated 31 relapsed cases of promyelocytic leukemia with arsenic trioxide. These cases relapsed after previous treatment with ATRA and chemotherapy. We applied arsenic trioxide as 0.15 mg/kg iv infusion until complete remission. After achieving complete remission patients received 2-4 consolidation therapy in the same schedule as remission induction. Results: The median age of patients was 27 years. Complete remission rate was 77.4%. We observed four mortalities during remission induction. With a median follow up of 32 months, ten more relapses occurred. Two year disease-free survival and overall survival for the entire cohort was 54.6% and 81.1%, respectively. Conclusion: Our result is the same as other studies. Thus, we suggest that arsenic trioxide can be used as salvage therapy in patients who relapsed. Despite a good complete remission rate, the relapse rate during the first two years of treatment is high and hematopoietic stem cell transplantation should be considered after achieving complete remission.