Acute and chronic graft-versus-host disease after ablative and nonmyeloablative conditioning for allogeneic hematopoietic transplantation.

In this study, we evaluated the influence of nonmyeloablative and ablative conditioning regimens on the occurrence of acute and chronic graft-versus-host disease (GVHD). One hundred thirty-seven patients undergoing matched-related sibling transplantations received the same GVHD prophylaxis. Myeloablative regimens included intravenous busulfan/cyclophosphamide (n=45) and fludarabine/melphalan (n=29). Patients in the nonmyeloablative group (n=63) received fludarabine/idarubicin/cytarabine, cisplatin/fludarabine/idarubicin, and fludarabine/cyclophosphamide. The actuarial rate of grade II to IV acute GVHD was significantly higher (hazard ratio, 3.6; 95% confidence interval, 1.5-8.8) in patients receiving ablative regimens (36%) compared with the nonmyeloablative group (12%). The cumulative incidence of chronic GVHD was higher in the ablative group (40%) compared with the nonmyeloablative group (14%). The rates were comparable within the first 200 days and were significantly higher in the ablative group beyond day 200 (hazard ratio, 5.2; 95% confidence interval, 1.2-23.2). Nonrelapse and GVHD-related mortality were relatively low in both groups. The use of the described nonmyeloablative preparative regimens was associated with a reduced incidence of grade II to IV acute GVHD and chronic GVHD compared with the busulfan/cyclophosphamide and fludarabine/melphalan transplant regimens. It is interesting to note that nonrelapse mortality with nonmyeloablative regimens in older and more debilitated patients was low (14%) and comparable to that achieved with standard high-dose regimens in younger patients.