BACKGROUND The majority of patients in need of a hematopoietic-cell transplant do not have a matched related donor. Data are needed to inform the choice among various alternative donor-cell sources. METHODS In this retrospective analysis, we compared outcomes in 582 consecutive patients with acute leukemia or the myelodysplastic syndrome who received a first myeloablative hematopoietic-cell transplant from an unrelated cord-blood donor (140 patients), an HLA-matched unrelated donor (344), or an HLA-mismatched unrelated donor (98). RESULTS The relative risks of death and relapse between the cord-blood group and the two other unrelated-donor groups appeared to vary according to the presence of minimal residual disease status before transplantation. Among patients with minimal residual disease, the risk of death was higher in the HLA-mismatched group than in the cord-blood group (hazard ratio, 2.92; 95% confidence interval [CI], 1.52 to 5.63; P = 0.001); the risk was also higher in the HLA-matched group than in the cord-blood group but not significantly so (hazard ratio, 1.69; 95% CI, 0.94 to 3.02; P = 0.08). Among patients without minimal residual disease, the hazard ratios were lower (hazard ratio in the HLA-mismatched group, 1.36; 95% CI, 0.76 to 2.46; P = 0.30; hazard ratio in the HLA-matched group, 0.78; 95% CI, 0.48 to 1.28; P = 0.33). The risk of relapse among patients with minimal residual disease was significantly higher in the two unrelated-donor groups than in the cord-blood group (hazard ratio in the HLA-mismatched group, 3.01; 95% CI, 1.22 to 7.38; P = 0.02; hazard ratio in the HLA-matched group, 2.92; 95% CI, 1.34 to 6.35; P = 0.007). Among patients without minimal residual disease, the magnitude of these associations was lower (hazard ratio in the HLA-mismatched group, 1.28; 95% CI, 0.51 to 3.25; P = 0.60; hazard ratio in the HLA-matched group, 1.30; 95% CI, 0.65 to 2.58; P = 0.46). CONCLUSIONS Our data suggest that among patients with pretransplantation minimal residual disease, the probability of overall survival after receipt of a transplant from a cord-blood donor was at least as favorable as that after receipt of a transplant from an HLA-matched unrelated donor and was significantly higher than the probability after receipt of a transplant from an HLA-mismatched unrelated donor. Furthermore, the probability of relapse was lower in the cord-blood group than in either of the other groups.

Purpose T-cell-replete HLA-haploidentical donor hematopoietic transplantation using post-transplant cyclophosphamide was originally described using bone marrow (BM). With increasing use of mobilized peripheral blood (PB), we compared transplant outcomes after PB and BM transplants. Patients and MethodsA total of 681 patients with hematologic malignancy who underwent transplantation in the United States between 2009 and 2014 received BM (n = 481) or PB (n = 190) grafts. Cox regression models were built to examine differences in transplant outcomes by graft type, adjusting for patient, disease, and transplant characteristics. ResultsHematopoietic recovery was similar after transplantation of BM and PB (28-day neutrophil recovery, 88% v 93%, P = .07; 100-day platelet recovery, 88% v 85%, P = .33). Risks of grade 2 to 4 acute (hazard ratio [HR], 0.45; P , .001) and chronic (HR, 0.35; P , .001) graft-versus-host disease were lower with transplantation of BM compared with PB. There were no significant differences in overall survival by graft type (HR, 0.99; P = .98), with rates of 54% and 57% at 2 years after transplantation of BM and PB, respectively. There were no differences in nonrelapse mortality risks (HR, 0.92; P = .74) but relapse risks were higher after transplantation of BM (HR, 1.49; P = .009). Additional exploration confirmed that the higher relapse risks after transplantation of BM were limited to patients with leukemia (HR, 1.73; P = .002) and not lymphoma (HR, 0.87; P = .64). ConclusionPB and BM grafts are suitable for haploidentical transplantation with the post-transplant cyclophosphamide approach but with differing patterns of treatment failure. Although, to our knowledge, this is the most comprehensive comparison, these findings must be validated in a randomized prospective comparison with adequate follow-up.