• relapsed APL;
  • arsenic trioxide;
  • all-trans retinoic acid

Summary.  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.