Second transplants for multiple myeloma relapsing after a previous autotransplant-reduced-intensity allogeneic vs autologous transplantation.

There is no standard therapy for multiple myeloma relapsing after an autotransplant. We compared the outcomes of a second autotransplant (N=137) with those of an allotransplant (N=152) after non-myeloablative or reduced-intensity conditioning (NST/RIC) in 289 subjects reported to the CIBMTR from 1995 to 2008. NST/RIC recipients were younger (median age 53 vs 56 years; P<0.001) and had a shorter time to progression after their first autotransplant. Non-relapse mortality at 1-year post transplant was higher in the NST/RIC cohort, 13% (95% confidence interval (CI), 8-19) vs 2% (95% CI, 1-5, P0.001). Three-year PFS and OS for the NST/RIC cohort were 6% (95% CI, 3-10%) and 20% (95% CI, 14-27%). Similar outcomes for the autotransplant cohort were 12% (95% CI, 7-19%, P=0.038) and 46% (95% CI, 37-55%, P=0.001). In multivariate analyses, risk of death was higher in NST/RIC recipients (hazard ratio (HR) 2.38 (95% CI, 1.79-3.16), P<0.001), those with Karnofsky performance score<90 (HR 1.96 (95% CI, 1.47-2.62), P<0.001) and transplant before 2004 (HR 1.77 (95% CI, 1.34-2.35) P0.001). In conclusion, NST/RIC was associated with higher TRM and lower survival than an autotransplant. As disease status was not available for most allotransplant recipients, it is not possible to determine which type of transplant is superior after autotransplant failure.