Induction therapy: Induction therapy will be continued till ANC> 1.5 x 10e9/L and Platelet count > 100 x 10e9/L along with the absence of abnormal promyelocytes in peripheral smear on 2 consecutive occasions. Once this is achieved, bone marrow studies will be done to assess remission. If the bone marrow shows < 5% of myeloblasts and promyelocytes along with a normocellular to mildly hypocellular marrow, arsenic can be stopped. If not in CR, arsenic is continued for an additional 2 weeks and a repeat bone marrow is done to confirm CR. Arsenic tri-oxide will be given for a maximum of 60 days following which the patient would be considered a non-responder/partial responder and excluded from further treatment. If bone marrow shows <5% blasts and promyelocytes at 60 days but peripheral blood count criteria for CR are not fulfilled, patient can be still be continued on the study regimen.