Haploidentical transplantation with post-transplant cyclophosphamide versus single cord blood transplantation in adults with relapsed/refractory non-Hodgkin lymphoma.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment for relapsed or refractory non-Hodgkin lymphoma (R/R NHL). Allo-HSCT using post-transplant cyclophosphamide (PTCY-haplo) and umbilical cord blood transplantation (uCBT) are important donor options in the absence of matched related siblings. However, the data comparing these two donor sources in R/R NHL are limited. Using the Japanese nationwide transplantation registry data, we identified 857 patients with R/R NHL, including 169 patients who received PTCY-haplo and 688 who received uCBT for their first allo-HSCT between January 2013 and December 2021; 514 patients (60%) had B-cell lymphoma. More PTCY-haplo recipients received allo-HSCT using a reduced-intensity conditioning regimen in recent years. The 3-year overall survival (OS), progression-free survival (PFS), and graft-versus-host disease (GVHD)-free/relapse-free survival (GRFS) rates in the PTCY-haplo and uCBT groups were 44% versus 39% (P = 0.326), 34% versus 33% (P = 0.660), and 19% versus 23% (P = 0.910), respectively; the adjusted hazard ratios for OS, PFS, and GRFS were 0.89 (95% confidence interval: 0.69-1.15, P = 0.373), 0.98 (0.78-1.22, P = 0.852), and 0.92 (0.83-1.21, P = 0.920), respectively. The PTCY-haplo group showed faster neutrophil and platelet engraftment and a lower incidence of grade III-IV acute GVHD. Thus, PTCY-haplo and uCBT could serve as alternative donor sources in patients with R/R NHL.