Combined arsenic trioxide and all-trans retinoic acid treatment for acute promyelocytic leukaemia recurring from previous relapses successfully treated using arsenic trioxide

The optimal treatment of acute promyelocytic leukaemia (APL) recurring from relapses successfully treated using arsenic trioxide (As2O3) is undefined. Three APL patients relapsing from As2O3-induced remission were studied. Re-treatment with As2O3 failed in one patient in third relapse, and resulted in morphological but not molecular remission in another patient. Combination therapy with As2O3 and all-trans retinoic acid (ATRA), however, resulted in morphological and molecular remission in all three cases, with a follow-up time ranging from 6 to 16 months. Our results suggest a synergistic therapeutic effect between As2O3 and ATRA in APL in advanced relapse.