<prompt> Drug used treatment of Acute promyelocytic leukemia-Arsenic trioxideTretinoinGefitinibDasatinib  <response>: Arsenic trioxide is effective and approved for treatment of relapsed or refractory acute promyelocytic leukemia APL cases resistant to all-trans retinoic acid ATRA, but its effect on new cases of APL is not clear. Ref Davidson 23rd edition pg 789 