Study Endpoints:
Patients were established to be under CR if they had an M1 marrow i.e., <5% blasts by bone marrow aspirate subsequent to second-line salvage induction therapy, without evidence of circulating blasts or extra-medullary disease and peripheral count recovery defined as ANC (absolute neutrophil count) > 0.75 x 10 9/L and Plt (platelet) count > 75 x 10 9/L. Patients who did not attain a CR subsequent to salvage induction therapy were determined to have induction failure. Successive relapses amongst patients who were in CR were pathologically defined confirmed as M3 marrow i.e., ≥ 25 % leukemic blasts or presence of extra-medullary disease. Overall survival duration of the cohort for disease-recurrence was determined from relapse date to date last seen and in case of a deceased patient date of demise was used , while overall survival of cohort for diagnosis was determined form diagnosis date to date last seen or date of demise in case of a deceased patient.