No significant difference in progression-free survival between cord blood and haploidentical transplantation for leukemia or lymphoma
Lower non-relapse mortality and superior overall survival favors haploidentical marrow over cord blood transplantation
Results of two parallel phase II trials of transplantation of unrelated umbilical cord blood or bone marrow from HLA-haploidentical relatives provided equipoise for direct comparison of these donor sources. Between June 2012 and June 2018, 368 patients aged 18-70 years with chemotherapy-sensitive lymphoma or acute leukemia in remission were randomly assigned to undergo cord blood (n=186) or haploidentical (n=182) transplant. Reduced intensity conditioning comprised total body irradiation with cyclophosphamide and fludarabine for both donor types. Graft-versus-host disease prophylaxis for cord blood transplantation was cyclosporine and mycophenolate mofetil and for haploidentical transplantation, post‐transplant cyclophosphamide, tacrolimus and mycophenolate mofetil. The primary endpoint was 2-year progression-free survival. Treatment groups had similar age, sex, self-reported ethnic origin, performance status, disease and disease status at randomization. Two-year progression-free survival was 35% (95% CI, 28-42%) compared to 41% (95% CI, 34-48%) after cord blood and haploidentical transplants, respectively (p=0.41). Pre-specified analysis of secondary endpoints recorded higher 2-year non-relapse mortality after cord blood, 18% (95% CI, 13-24%) compared to haploidentical transplantation, 11% (95% CI, 6-16%), p=0.04. This led to lower 2-year overall survival after cord blood compared to haploidentical transplantation, 46% (95% CI, 38-53) and 57% (95% CI 49-64%), respectively (p=0.04). The trial did not demonstrate a statistically significant difference in the primary endpoint, 2-year progression-free survival, between the donor sources. While both donor sources extend access to reduced intensity transplantation, analyses of secondary endpoints, including overall survival, favor haploidentical bone marrow donors. (Funded by the National Heart, Lung, and Blood Institute-National Cancer Institute; ClinicalTrials.gov number, NCT01597778).