T-cell-replete HLA-haploidentical hematopoietic transplantation for hematologic malignancies using post-transplantation cyclophosphamide results in outcomes equivalent to those of contemporaneous HLA-matched related and unrelated donor transplantation

Abstract

Purpose: T-cell-replete grafts from haploidentical donors using post-transplantation cyclophosphamide may represent a solution for patients who require allogeneic hematopoietic cell transplantation (alloHCT) but lack a conventional donor. We compared outcomes of alloHCT using haploidentical donors with those of transplantation using conventional HLA-matched sibling donors (MRDs) and HLA-matched unrelated donors (MUDs).

Patients and methods: Outcomes of 271 consecutive patients undergoing T-cell-replete first alloHCT for hematologic malignancies performed contemporaneously at a single center (53 using haploidentical donors; 117, MRDs; 101, MUDs) were compared. Overall and disease-free survival (DFS) were adjusted for effects of significant patient-, disease-, and transplantation-related covariates using a stratified Cox model.

Results: Patient characteristics were similar between the three donor groups. For patients undergoing MRD, MUD, and haploidentical transplantation, 24-month cumulative incidences of nonrelapse mortality were 13%, 16%, and 7% and of relapse were 34%, 34%, and 33%, respectively (P not significant [NS]). Cumulative incidences of grades 3 to 4 acute graft-versus-host disease (GVHD) at 6 months were 8%, 11%, and 11%, respectively (P NS); extensive chronic GVHD occurred in 54%, 54%, and 38% of patients, respectively (P < .05 for those undergoing haploidentical donor v MRD or MUD transplantation). Adjusted 24-month probabilities of survival were 76%, 67%, and 64% and of DFS were 53%, 52%, and 60%, respectively; these were not significantly different among the three donor groups.

Conclusion: Haploidentical transplantation performed using T-cell-replete grafts and post-transplantation cyclophosphamide achieves outcomes equivalent to those of contemporaneous transplantation performed using MRDs and MUDs. Such transplantation represents a valid alternative for patients who lack a conventional donor.