Effect of Graft-versus-Host Disease on Post-Transplantation Outcomes following Single Cord Blood Transplantation Compared with Haploidentical Transplantation with Post-Transplantation Cyclophosphamide for Adult Acute Myeloid Leukemia.

The possibility that HLA mismatches could reduce relapse after alternative HLA-mismatched allogeneic hematopoietic cell transplantation (HCT) is an attractive concept for treating acute myeloid leukemia (AML). However, it remains unclear whether the prognostic effect of graft-versus-host disease (GVHD) on survival differs between recipients of single-unit cord blood transplantation (CBT) and recipients of haploidentical HCT using post-transplantation cyclophosphamide (PTCy-haplo-HCT) for AML. The objective of this retrospective study was to compare the effect of acute GVHD and chronic GVHD on post-transplantation outcomes between recipients of CBT and recipients of PTCy-haplo-HCT. We retrospectively evaluated the effect of acute and chronic GVHD on post-transplantation outcomes following CBT and PTCy-haplo-HCT in adults with AML (n = 1981) between 2014 and 2020 using a Japanese registry database. In univariate analysis, the probability of overall survival was significantly greater in patients who developed grade I-II acute GVHD (P < .001, log-rank test) and limited chronic GVHD (P < .001, log-rank test) among CBT recipients, but these effects were not significant among PTCy-haplo-HCT recipients. In multivariate analysis, in which the development of GVHD was treated as a time-dependent covariate, the effect of grade I-II acute GVHD on reducing overall mortality differed significantly between CBT and PTCy-haplo-HCT (adjusted hazard ratio [HR] for CBT, .73, 95% confidence interval [CI], .60 to .87; adjusted HR for PTCy-haplo-HCT, 1.07; 95% CI, .70 to 1.64; P for interaction = .038). Our data demonstrate that grade I-II acute GVHD was associated with a significant improvement in overall mortality in adults with AML receiving CBT but not in recipients of PTCy-haplo-HCT.