- Determine, preliminarily, the safety of incorporating arsenic trioxide (ATO) into cytarabine and daunorubicin hydrochloride-based consolidation therapy followed by tretinoin maintenance therapy in patients receiving induction tretinoin and daunorubicin hydrochloride with acute promyelocytic leukemia (APL) induced into remission with tretinoin and daunorubicin hydrochloride.