Multicenter phase 3 trial of addition of decitabine to BuCy conditioning before alloHSCT in adult KMT2A-rearranged leukemia

The optimal myeloablative conditioning regimen before alloHSCT in adult KMT2A-rearanged leukemia is not known. A phase 3 trial at eight centers in China compared conditioning with decitabine (DAC) plus busulfan-cyclophophamide (BuCy) versus BuCy alone. A total of 130 patients were randomized to receive DAC-BuCy (n-=65) or BuCy (n=65). Median follow-up was 34.7 months (IQR 30.2-52.5). Two-year cumulative incidence of relapse was 12% in the DAC-BuCy group and 29% in the BuCy group (HR 0.41; p=0.017). The most common grade 3-5 adverse events were infection or infestation (42% in the DAC-BuCy group and 38% in the BuCy group), acute graft-versus –host disease (35% versus 34%), and gastro-intestinal disorders (22% versus 23%). Four patients (6%) in the DAC-BuCy group and five (8%) in the BuCy group died from adverse events, of which two (one in each group) were due to regimen-related toxicities. The authors conclude that the addition of decitabine to BuCy conditioning reduced the risk of relapse with an acceptable safety profile in adult patients with KMT2A-rearranged leukemia.