Effect of Graft Source on Unrelated Donor Hemopoietic Stem Cell Transplantation in Adults with Acute Myeloid Leukemia after Reduced-Intensity or Nonmyeloablative Conditioning: A Study from the Societe Francaise de Greffe de Moelle et de Therapie Cellulaire

This retrospective report compared the 4-year outcomes of allogeneic stem cell transplantation (allo-SCT) in 651 adult patients with acute myeloid leukemia receiving a reduced-intensity (RIC) or nonmyeloablative conditioning (NMA) regimen according to the type of unrelated donors. These were either umbilical cord blood (UCB, n = 205), a 9/10 mismatched unrelated donor (MisMUD, n = 99), or a 10/10 matched unrelated donor (MUD, n = 347) graft. Neutrophil recovery was slower in UCB (74.5% by day 42) compared with MisMUD (94.8%) and MUD (95.6%) (P < .001). There was no significant difference in nonrelapse mortality between UCB and both MUD (hazard ratio Din 1.05; 95% confidence interval [CI], .62 to 1.78; P = .85) and MisMUD (HR, 1.58; 95% CI, .88 to 2.83; P = .13) The relapse/progression was similar between UCB and MisMUD (HR,.62; 95% CI,.37 to 1.03; P = .07), but was significantly lower in MUD compared with UCB (HR, .60; 95% CI, .39 to .92; P = .02). The rate of extensive chronic graft-versus-host disease (GVHD) was similar between UCB and both MUD (HR, 2.15; 95% CI, .93 to 4.97; P = .08) and MisMUD (HR, 1.84; 95% CI, .68 to 4.95; P = .23). The rate of severe grade III and IV acute GVHD was significantly increased in MisMUD compared with UCB (HR, 2.61; 95% CI, 1.30 to 5.23; P = .007). There was no significant difference in overall survival between UCB and both MisMUD (HR, .98; 95% CI, .66 to 1.45; P = .92) and MUD (HR, .74; 95% CI, .52 to 1.03; P = .08). These data suggest that in the setting of RIC/NMA, allo-SCT UCB is a valid alternative graft source, with significantly less chronic GVHD, compared with MisMUD, when there is no MUD available or when urgent transplantation is needed. (C) 2015 American Society for Blood and Marrow Transplantation.