Idarubicin plus BuCy versus BuCy conditioning regimens for intermediate-risk acute myeloid leukemia in first complete remission undergoing auto-HSCT: An open-label, multicenter, randomized phase 3 trial.

We report a randomized prospective phase 3 study, designed to evaluate the efficacy and tolerability of idarubicin plus busulfan and cyclophosphamide (IDA-BuCy) versus BuCy in autologous hematopoietic stem-cell transplantation (auto-HSCT) for intermediate-risk acute myeloid leukemia (IR-AML) patients in first complete remission (CR1). One hundred and fifty-four patients were enrolled and randomized to receive IDA-BuCy (IDA 15 mg/m2/day on days -12 to -10, Bu 3.2 mg/kg/day on days -7 to -4, and Cy 60 mg/kg/day on days -3 to -2) or BuCy. The 2-year incidence of relapse was 15.6% and 19.5% in IDA-BuCy and BuCy groups (p = 0.482), respectively. There was no significant overall survival (OS) and disease-free survival (DFS) benefit for IR-AML patients receiving IDA-BuCy (2-year OS 81.8% in IDA-BuCy vs. 83.1% in BuCy, p = 0.798; 2-year DFS 76.6% in IDA-BuCy vs. 79.2% in BuCy, p = 0.693). Grade 3 or worse regimen-related toxicity (RRT) was reported for 22 (28.9%) of 76 and 9 (12.0%) of 75 patients in two groups (p = 0.015), respectively. AEs within 100 days with an outcome of death were reported for 4 (5.3%) and 0 patients in two groups. In conclusion, IDA-BuCy has higher RRT and similar anti-leukemic activity compared with BuCy in IR-AML patients in CR1 undergoing auto-HSCT. Thus, caution should be taken when choosing IDA-BuCy for IR-AML patients in CR1 with auto-HSCT. This trial is registered with ClinicalTrials.gov, NCT02671708, and is complete.