comparison of haploidentical bone marrow versus matchet unrelated donor peripheral blood stem cell transplantation with posttransplant cyclophosphamide in patients with acute leukemia

Purpose:Posttransplant cyclophosphamide (PTCy) is increas-ingly being utilized as a principle GvHD prophylaxis strategy inallogeneic hematopoietic cell transplantation (allo-HCT). A hap-loidentical (haplo) or matched unrelated donor (UD) is a validoption in the absence of a matched related donor.Experimental Design:We compared the outcomes of patientswith acute leukemia who underwent haplo bone marrow (haplo-BM,N¼401) versus UD mobilized peripheral blood stem cells (UD-PB,N¼192) transplantation in the setting of PTCy.Results:The median follow-up duration was 36 months in thehaplo-BM group and 16.6 months in the UD-PB group, respectively(P<0.01). Myeloablative conditioning was used in 64.6% and 42.7%of haplo-BM and UD-PB patients, respectively (P<0.01). Cumu-lative incidence of neutrophil engraftment at day 30 was 87% inhaplo-BM versus 94% in UD-PB, respectively (P¼0.21). In themultivariate analysis, the risk of grade 2–4 acute GvHD (HR¼0.53,P¼0.01) and chronic GvHD (HR¼0.50,P¼0.02) was signif-icantly lower in the haplo-BM group compared with the UD-PBgroup. There was no significant difference between the studygroups with respect to relapse incidence, nonrelapse mortality,leukemia-fee survival, overall survival, or GvHD-free and relapse-free survival.Conclusions:The use of a haplo donor with a BM graft resultedin a lower incidence of GvHD compared with a UD-PB stem cellgraft in the setting of PTCy for patients with acute leukemia.However, differences in GvHD did not translate into a differencein survival outcomes. Based upon these data, UD-PB or haplo-BMshould be considered equally acceptable sources for allo-HCT