Comparative outcomes of various transplantation platforms, highlighting haploidentical transplants with post‐transplantation cyclophosphamide for adult T‐cell leukaemia/lymphoma

Abstract

Summary This study retrospectively compared outcomes of various allogeneic haematopoietic cell transplantation (allo‐HCT) platforms in patients with adult T‐cell leukaemia/lymphoma. Platforms included human leukocyte antigen (HLA)‐haploidentical‐related donors using post‐transplant cyclophosphamide (PTCY), HLA‐matched related donors (MRD), HLA‐matched unrelated donors (MUD) and cord blood transplantation (CBT). Patients who underwent their first allo‐HCT between 2016 and 2021 were included. Outcomes analysed were overall survival (OS), relapse and non‐relapse mortality (NRM). Seven hundred patients were included (PTCY, n = 121; MRD, n = 91; MUD, n = 160; CBT, n = 328). With a median follow‐up of 794 days for survivors, 2‐year OS was 48.1% (PTCY), 48.8% (MRD), 48.4% (MUD) and 34.6% (CBT); the respective 2‐year cumulative incidence of relapse was 37.1%, 47.5%, 33.9% and 45.1% and that of NRM was 24.2%, 19.8%, 24.7% and 27.3%. PTCY was associated with delayed platelet engraftment relative to MRD and MUD. There was no increase in the incidence of severe acute or chronic graft‐versus‐host disease. In the PTCY group, poor performance status was a significant predictor of inferior OS, and infused CD34+ cell numbers of less than 5 × 10 6 /kg were associated with delayed neutrophil and platelet engraftment. These results suggest that allo‐HCT with PTCY is a safe and effective platform for patients with adult T‐cell leukaemia/lymphoma.