Higher survival following transplantation with a mismatched unrelated donor with posttransplant cyclophosphamide‐based graft‐versus‐host disease prophylaxis than with double unit umbilical cord blood in patients with acute myeloid leukemia in first complete remission: A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Abstract

AbstractThe best donor option for acute myeloid leukemia (AML) patients lacking an HLA‐matched donor has remained intensively debated. We herein report the results of a large retrospective registry study comparing hematopoietic cell transplantation (HCT) outcomes between double‐unit umbilical cord blood transplantation (dCBT, n = 209) versus 9/10 HLA‐matched unrelated donor (UD) with posttransplant cyclophosphamide (PTCy)‐based graft‐versus‐host disease (GVHD) prophylaxis (UD 9/10, n = 270) in patients with AML in first complete remission (CR1). Inclusion criteria consisted of adult patient, AML in CR1 at transplantation, either peripheral blood stem cells (PBSC) from UD 9/10 with PTCy as GVHD prophylaxis or dCBT without PTCy, transplantation between 2013 and 2021, and no in vivo T‐cell depletion. The 180‐day cumulative incidence of grade II‐IV acute GVHD was 29% in UD 9/10 versus 44% in dCBT recipients (p = .001). After adjustment for covariates, dCBT recipients had a higher non‐relapse mortality (HR = 2.35, 95% CI: 1.23–4.48; p = .01), comparable relapse incidence (HR = 1.12, 95% CI: 0.67–1.86; p = .66), lower leukemia‐free survival (HR = 1.5, 95% CI: 1.01–2.23; p = .047), and lower overall survival (HR = 1.66, 95% CI: 1.08–2.55; p = .02) compared with patients receiving UD 9/10 HCT. In summary, our results suggest that transplantation outcomes are better with UD 9/10 with PTCy‐based GVHD prophylaxis than with dCBT for AML patients in CR1. These data might support the use of UD 9/10 with PTCy‐based GVHD prophylaxis over dCBT in AML patients lacking an HLA‐matched donor.