Oral arsenic trioxide incorporation into frontline treatment with all‐trans retinoic acid and chemotherapy in newly diagnosed acute promyelocytic leukemia: A 5‐year prospective study

BACKGROUND: Strategies using oral arsenic trioxide (As2 O3 ) are efficacious in relapsed acute promyelocytic leukemia (APL), but they have not been examined in newly diagnosed cases. METHODS: Sixty-two consecutive patients (24 men and 38 women) with a median age of 52 years (range, 22-85 years), 36% of whom had high-risk features, underwent induction with all-trans retinoic acid at 45 mg/m2 /d, oral As2 O3 at 10 mg/d, and ascorbic acid at 1 g/d (the all-trans retinoic acid-arsenic trioxide-ascorbic acid [AAA] regimen) for 6 weeks (with patients younger than 70 years additionally receiving daunorubicin at 50 mg/m2 /d × 3); they then underwent consolidation with 2 monthly cycles of daunorubicin (50 mg/m2 /d × 2) and cytarabine (100 mg/m2 /d × 5) and received AAA maintenance (2 weeks every 8 weeks) for 2 years. A contemporaneous cohort of 37 newly diagnosed patients (15 men and 22 women) with a median age of 51 years (range, 23-78 years), not consenting to oral As2 O3 induction but receiving similar induction, consolidation, and AAA maintenance, served as a comparator group; 46% of these patients had high-risk features. RESULTS: The oral As2 O3 induction cohort showed a complete remission (CR) rate of 100%. After a median of 37 months (range, 13-82 months), there were no relapses, so conventional risks (age, leukocyte and platelet counts, and Fms-like tyrosine kinase 3 [FLT3] mutations) were not relevant. The leukemia-free survival (LFS) and overall survival (OS) rates were 100% at 3 years and 94.1% at 5 years. The non-As2 O3 induction cohort showed a CR rate of 100%. After a median of 52 months (range, 14-77 months), there were 3 relapses (8%). Comparable patients in the oral As2 O3 induction and non-As2 O3 induction cohorts showed similar OS, but LFS was significantly superior in the oral As2 O3 induction cohort. CONCLUSIONS: The incorporation of oral As2 O3 into induction for newly diagnosed APL was safe and decreased relapses.