Allogeneic transplantation of multiple myeloma patients may allow long-term survival in carefully selected patients with acceptable toxicity and preserved quality of life.

Despite significantly improved survival and response rates in patients diagnosed with multiple myeloma, it still remains an incurable disease with a poor outcome, especially in high-risk groups. Allogeneic stem cell transplantation offers a potentially curative option but remains controversial due to considerable treatment-related toxicity. We analyzed 109 consecutive myeloma patients who had received reduced-intensity conditioning allogeneic transplantation at the Freiburg University Medical Center between 2000 and 2016. Although most patients were heavily pre-treated in high-risk constellations, the overall response rate was high with 70%, the median overall survival (OS) 39.2%, and the median progression-free survival (PFS) 14.2 months, with a median follow up of 71.5 months. Survival was significantly better in patients with response to previous therapies than in those with progressive disease (median OS 65 vs. 11.5 months, P =0.003; median PFS 18.4 vs. 5.1 months, P =0.001). Moreover, survival of patients transplanted in first-line was significantly prolonged compared to relapsed/refractory disease (median OS not reached vs. 21.6 months, P <0.001; median PFS 47.7 vs. 9.6 months, P <0.001). The non-relapse mortality was relatively low with a cumulative incidence of 12.4% at ten years. Acute graft- versus -host disease (GvHD) grade II-IV was observed in 25%, and moderate or severe chronic GvHD in 24%. Quality of life (QoL) assessed with the revised Myeloma Comorbidity Index before and after transplantation remained unchanged. Our data suggest that allogeneic transplantation in the context of novel immunotherapeutic approaches may enable long-term survival and even a potential cure in a carefully selected subgroup of high-risk multiple myeloma patients with acceptable toxicity and preserved QoL.