Impact of graft-versus-host disease after reduced-intensity conditioning allogeneic stem cell transplantation for acute myeloid leukemia: a report from the Acute Leukemia Working Party of the European group for blood and marrow transplantation

This report investigated the impact of graft-versus-host disease (GVHD) on transplantation outcomes in 1859 acute myeloid leukemia patients given allogeneic peripheral blood stem cells after reduced-intensity conditioning (RIC allo-SCT). Grade I acute GVHD was associated with a lower risk of relapse (hazards ratio (HR) 0.7, P = 0.02) translating into a trend for better overall survival (OS; HR 1.3; P = 0.07). Grade II acute GVHD had no net impact on OS, while grade III-IV acute GVHD was associated with a worse OS (HR 0.4, P < 0.0.001) owing to high risk of nonrelapse mortality (NRM; HR 5.2, P < 0.0001). In time-dependent multivariate Cox analyses, limited chronic GVHD tended to be associated with a lower risk of relapse (HR 0.72; P = 0.07) translating into a better OS (HR 1.8; P < 0.001), while extensive chronic GVHD was associated with a lower risk of relapse (HR 0.65; P = 0.02) but also with higher NRM (HR 3.5; P < 0.001) and thus had no net impact on OS. In-vivo T-cell depletion with antithymocyte globulin (ATG) or alemtuzumab was successful at preventing extensive chronic GVHD (P < 0.001), but without improving OS for ATG and even with worsening OS for alemtuzumab (HR 0.65; P = 0.001). These results highlight the role of the immune-mediated graft-versus-leukemia effect in the RIC allo-SCT setting, but also the need for improving the prevention and treatment of severe GVHD. Leukemia (2012) 26, 2462-2468; doi: 10.1038/leu.2012.135