Comparison of Outcomes of Hematopoietic Cell Transplants from T-Replete Haploidentical Donors Using Post-Transplantation Cyclophosphamide with 10 of 10 HLA-A, -B, -C, -DRB1, and -DQB1 Allele-Matched Unrelated Donors and HLA-Identical Sibling Donors: A Mul

•T-replete grafts from haploidentical and MUD donors produce similar survival.•Chronic GVHD is lower following haploidentical than MUD donor transplants.•Less chronic GVHD in haploidentical transplants is independent of PBSC vs BM source.•These results are confirmed in multivariate analysis.

Outcomes of 475 consecutive patients undergoing first allogeneic transplantation for hematologic malignancy performed using T-replete HLA-haploidentical donors and post-transplantation cyclophosphamide (HIDT; n = 116) were compared with contemporaneous patients transplanted from 10 of 10 HLA allele-matched unrelated donors (MUDT; n = 178) or HLA-identical sibling donors (MRDT; n = 181). Uniform supportive care measures and assessments were used. Median follow-up was 45 months. HIDT patients were more likely than MUDT patients to be black (44% versus 2%; P < .001). At 2 years after transplantation, estimates of overall survival were 57% for HIDT, 59% for MUDT, and 72% for MRDT (P not significant [NS] for HIDT versus MUDT; P = .02 for HIDT versus MRDT); corresponding disease-free survival rates were 54%, 50%, and 56% (P NS for both comparisons). The respective cumulative incidences (CIs) of nonrelapse mortality were 17%, 16%, 14%, and those of relapse were 29%, 34%, and 30% (P NS for all). The respective CIs of acute graft-versus-host disease (GVHD) grade II-IV were 41%, 48%, and 28% (P = NS for HIDT versus MUDT; P = .005 for HIDT versus MRDT). At 2 years, the respective CIs of moderate/severe chronic GVHD were 31%, 47%, and 44% (P = .004 for HIDT versus MUDT; P = .032 for HIDT versus MRDT) and 19% of HIDT recipients, 42% of MUDT recipients, and 35% of MRDT recipients were on systemic immunosuppressive treatment (P = .007 for HIDT versus MUDT). In recipients of peripheral blood stem cell grafts, the incidence of moderate-severe chronic GVHD was significantly lower in HIDT recipients compared with MUDT recipients (2-year CI, 25% versus 48%; P = .002). In a multivariate analysis incorporating Disease Risk Index and other significant covariates, survival (hazard ratio [HR], 1.31; P = .15) and disease-free survival (HR, 0.96; P = .79) were not significantly different between HIDT and MUDT recipients, but the incidence of chronic GVHD was lower in HIDT recipients (moderate-severe, HR, 0.59; P = .007). HIDT produced similar long-term survival with lower rates of chronic GVHD than optimally matched MUDT. HIDT should be considered a standard of care option for patients lacking a matched sibling donor.