Allogeneic stem cell transplantation and subsequent treatments as a comprehensive strategy for long-term survival of multiple myeloma patients

We evaluated 71 patients treated with allogeneic hematopoietic cell transplantation (allo-HCT) for multiple myeloma (MM). Forty-three patients (61%) received allo-HCT after the first line of therapy. Fifty-eight patients (82%) had chemosensitive disease at the time of allo-HCT. A HLA-matched related or unrelated donor was available for 68 patients (96%). Non-myeloablative or reduced-intensity conditioning regimen and peripheral blood hematopoietic cells as a graft source were used in most patients. The cumulative incidence of grade II-IV acute GVHD at day +100 and chronic GVHD at 5 years was 13% (95% CI 7-23%) and 35% (95% CI 24-46), respectively. Non-relapse mortality and relapse/progression incidence at 5 years were 12% (95% CI 5-23) and 65% (95% CI 49-76), respectively. With a median follow-up in survivors of 100 months (range 16-186), the 5-year PFS and OS were 39% (95% CI 27-52) and 60% (95% CI 55-77), respectively. On multivariate analysis: age >55 years was associated with both a reduced PFS (RR 2.11, 95% CI 1.15-3.87) and OS (RR 5.53, 95% CI 2.22-13.76); chemorefractory disease at allo-HCT was associated with both reduced PFS (RR 3.09, 95% CI 1.37-7.00) and OS (RR 3.19, 95% CI 1.23-8.22). At relapse, 24 patients (56%) received bortezomib, 28 (65%) lenalidomide, 11 (26%) pomalidomide, 16 (37%) donor lymphocytes infusion as part of salvage therapy after allo-HCT relapse. Median PFS from time of salvage treatment was 7 months (range 0-113 months) for bortezomib-based therapy, 14 months (range 0-79 months) for lenalidomide and 10 months (range 1-28) for pomalidomide. Allo-HCT is a feasible and effective strategy in selected patients with MM and could be an effective platform for subsequent therapies.