LAUSR

Patients with acute megakaryoblastic leukaemia of Down syndrome (DS‐AMKL) have an excellent survival rate; however, patients with non‐DS‐AMKL experience poor outcomes. Therefore, this study retrospectively analysed 203 children with non‐DS‐AMKL who underwent their first haematopoietic cell transplantation (HCT) from 1986 to 2015 using a nationwide Japanese HCT registry data to assess HCT outcomes for non‐DS‐AMKL. The 5‐year overall survival (OS) and event‐free survival (EFS) rates were 43% and 38% respectively. The 5‐year OS rate was significantly higher for patients who underwent HCT in the first complete remission (CR1, 72%) than for those in the second CR (CR2, 23%) and non‐CR (16%) (p < 0.001), and for those from a human leukocyte antigen (HLA)‐matched (52%) than for those from an HLA‐mismatched donor (27%) (p < 0.001). Multivariate analysis for OS revealed that HCT in CR2 and non‐CR was a significant risk factor (hazard ratio, 5.86; 95% confidence interval, 3.56–9.53; p < 0.001). The 3‐year EFS in patients who received HCT in CR1 using reduced‐intensity conditioning (RIC, 35%) was significantly lower than in those using myeloablative conditioning (busulfan‐based, 71%; total body irradiation‐based, 58%) (p < 0.001). Risk stratification in patients with non‐DS‐AMKL should be established to determine HCT indication in CR1.