Effect of graft source on mismatched unrelated donor hemopoietic stem cell transplantation after reduced intensity conditioning.

This retrospective report compared the results of graft source on outcome after allogeneic stem cell transplantation (allo-SCT) in patients with hematologic malignancies receiving a reduced intensity conditioning (RIC) regimen. A total of 152 patients received either a RIC allo-SCT using a 9/10 mismatched unrelated donor (MisMUD, n=42) or a double unrelated umbilical cord blood (dUCB, n=110) graft. With a median follow-up of 30.3 months, the cumulative incidence of non-relapse mortality was 26% in the dUCB group versus 24% in the MisMUD group (P=0.95). Grade 3-4 acute graft-versus-host disease (GVHD) incidence was 19.7% in the dUCB group versus 21.4% in the MisMUD group (P=0.83). The cumulative incidence of extensive chronic GVHD at 2 years was 6.4% in the dUCB group versus 21.4% in the MisMUD group (P=0.02). The Kaplan-Meier estimate of overall survival at 2 years was comparable between both groups (52.3% (95% confidence interval (CI), 42.1-61.5%) in the dUCB group versus 47.9% (95% CI, 31.6-62.4%) in the MisMUD group, P=0.55). Progression-free survival at 2 years was 43.3% (95% CI, 33.7-52.5%) in the dUCB group versus 38.3% (95% CI, 23.2-53.3%) in the MisMUD group (P=0.55). These data suggest that dUCB is a valid alternative graft source with significantly less chronic GVHD compared with MisMUD in the setting of RIC allo-SCT.