All-trans retinoic acid + arsenic trioxide versus other regimens for the treatment of acute promyelocytic leukemia: A single institution experience.

e19010 Background: All-trans retinoic acid (ATRA) and arsenic trioxide (ATO) have revolutionized the treatment of acute promyelocytic leukemia (APML). Anthracycline is added at induction for high risk patients. Adding maintenance therapy after induction and consolidation with ATRA + ATO has not been rigorously tested. In early 2007, we standardized our institutional practice to use ATRA + ATO alone for low risk patients, adding idarubicin to the combination for high risk patients. Maintenance therapy was not given. Methods: We reviewed 36 patients with APML diagnosed between 2000 and 2016. We compared the overall survival (OS) and event-free survival (EFS) of patients treated with the combination of ATRA + ATO (Cohort_AA) with patients treated on other regimens (Cohort_OT) at our institution. 7 patients in Cohort_OT were treated on CALGB 9710. Cohort_AA received induction with ATRA 45 mg/m2 and ATO 0.15 mg/kg IV both daily until hematological remission. High-risk patients received idarubicin on days 2, 4, 6 ± 8. Consolidation consisted of ATO for 5 days/week for 4 weeks every 8 weeks for 4 cycles and ATRA for 14 days every 4 weeks for 7 cycles. Results: Median follow-up was 30 months (range: 6-208 months) for the entire group. OS of Cohort_AA (n = 20) was 100% with a median follow-up of 22 months (range: 6-130) and 75% in Cohort_OT (n = 16) with a median follow-up of 84 months (range 8-208) (p = 0.0462). EFS was 100% (Cohort_AA) and 68% (Cohort_OT) (p = 0.0458). There were four relapses and three deaths (2 within one year) in Cohort_OT. There are no relapses or deaths in Cohort_AA. Patients in both groups were stratified according to high or low risk. There was no difference in terms of risk stratification between the two groups (p = 0.36). Conclusions: ATRA + ATO with idarubicin for high-risk disease and without maintenance is a feasible and superior treatment when compared to other regimens used at our institution. It is unlikely that maintenance therapy would improve survival. With the advent of molecular testing, clinical trials designed to test tailored therapy based upon risk and molecular response would seem to be a logical next step.