Objectives: The aim of this study was to identify prognostic factors for outcome of high-risk patients with multiple myeloma after allogeneic transplantation prepared by reduced intensity conditioning (RIC).
Materials and methods: Data from 45 consecutive patients (median age 52 years, range 38-68), who received grafts from a sibling (n = 34) or unrelated donor (n = 11) were analyzed. Fourteen patients received an RIC allotransplant while chemosensitive (>/=partial remission [PR]), whereas 31 chemoresistant patients (<PR) had either relapsed (n = 28) or were refractory (n = 3) after one or more autografts; of these 28 patients, 4 had secondary myelodysplasia concurrent with relapse. Of the 14 chemosensitive patients, 12 received an RIC allotransplant as consolidation after an autotransplant (AT).
Results: Twenty-nine (64%) were in a complete remission (CR) or near CR, 5 were in PR, and 5 had progressive disease. Twenty-five patients died, 17 of transplant-related complications, 7 of progressive disease, and 1 of a nontransplant-related cause. With a median follow-up of 15 months, the following factors were significantly associated with a better event-free survival (EFS) probability at 3 years: chemosensitive disease (64% vs 12%), pretransplant performance score (PS, Zubrod) </=2 (36% vs 0%), CR + near CR post transplant (36% vs 0%), and presence of chronic graft-vs-host disease (GVHD; 29% vs 0%). The same factors and absence of grade III to IV acute GVHD (52% vs 0%) were significant for a better overall survival (OS). On multivariate analysis including only pretransplant factors, both chemosensitive response and PS </=2 were significant for overall survival and event-free survival (p < 0.01). When response to RIC allotransplant and GVHD were added to the model, chronic GVHD was significant for better event-free survival, with an odds ratio of 1.5 (p < 0.01).
Conclusions: Our data suggest that although RIC allotransplant induces high rates of CR and near CR, even in refractory disease, it appears to result in a durable response only if it is applied early in the disease in high-risk patients, when they still are chemosensitive and have an adequate PS.