Reduced-Intensity Allogeneic Hematopoietic Stem Cell Transplantation for Relapsed Multiple Myeloma

Despite recent advances, multiple myeloma (MM) remains incurable, and most patients eventually develop progressive disease. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) offers a potentially curative option in 10%-20% of patients with relapsed or refractory disease. We evaluated the outcome of patients undergoing allo-HSCT with reduced-intensity conditioning (RIC) for relapsed and/or refractory MM at our institution. The study cohort included 51 patients with heavily pretreated, relapsed MM who underwent RIC allo-HSCT between 1996 and 2006. The median time from diagnosis to allo-HSCT was 34 months, and median follow-up in surviving patients was 27 months (range, 3-98 months). Cumulative transplantation-related mortality at 1 year was 25%. Progression-free survival (PFS) and overall survival (OS) at 2 years were 19% and 32%, respectively. The incidences of grade II-IV acute and chronic graft-versus-host disease were 27% and 47%, respectively. At the time of this analysis, 12 patients (24%) were alive, 7 of whom (14%) were in remission for up to 6 years after allo-HSCT. A lower β2 microglobulin level (