Unmanipulated haploidentical hematopoietic stem cell transplantation for mixed phenotype acute leukemia: a single center study

Abstract Mixed-phenotype acute leukemia (MPAL), which is categorized as a rare subtype of acute leukemia with a generally dismal prognosis. Hemopoietic stem cell transplantation (HSCT) is traditionally considered a curative treatment for MPAL. Thirty-three MPAL patients undergoing HSCT at the Peking University Institute of Hematology, Peking University People’s Hospital (Beijing, China) between December 2017 and April 2022 were enrolled in this study. The 2-year overall survival (OS) rate was 84.4% (95% confidence interval [95% CI], 69.9–98.9%), and the event-free survival (EFS) rate was 86.3% (95% CI, 73.8–98.8%) in MPAL patients undergoing HSCT in first complete remission (CR1). The median time to relapse after HSCT was 7.2 months (range: 0.8–12 months). The 2-year cumulative incidence of relapse (CIR) was 13.7% (95% CI, 4.2–28.9%). No patients died due to non-relapsed mortality (NRM) events. This study suggested that haplo-HSCT is a feasible and safe strategy for patients with MPAL patients in CR1. The outcomes were promising; however, they need to be confirmed by further research.