Allogeneic hematopoietic cell transplant for multiple myeloma using reduced intensity conditioning therapy, 1998-2006: factors associated with improved survival outcome.

This study reports on the outcome of 95 allogeneic hematopoietic cell transplants (HCTs) using reduced intensity conditioning (RIC) performed for patients with multiple myeloma (MM) in Australia and New Zealand between 1998 and 2006. The median age at HCT was 52 years. Of the 32 patients for whom the allograft was performed as a first transplant, 15 (47%) had their allograft less than 1 year from diagnosis, while for the 63 patients who had an allograft following an autograft, nine (14%) were allografted within 1 year post-diagnosis (p < 0.001). The cumulative incidence of transplant-related mortality (TRM) was 19% at 1 year post-transplant. At 5 years post-transplant the overall survival (OS) was 40% and progression-free survival (PFS) was 23%, with no apparent survival plateau. Three factors were independently favorable predictors of OS in a Cox regression model: immunoglobulin G (IgG) myeloma (hazard ratio [HR] = 0.42, 95% confidence interval [CI] 0.24-0.75, p = 0.004), a human leukocyte antigen (HLA)-identical sibling donor (HR = 0.37, 95% CI 0.18-0.74, p = 0.005), and less than 1 year between MM diagnosis and RIC HCT (HR = 0.27, 95% CI 0.12-0.59, p = 0.001). Patterns of outcome indicate that RIC HCT may offer the potential for cure for only a small group of patients with MM.