Tandem autologous/reduced-intensity allogeneic stem cell transplantation versus autologous transplantation in myeloma – long term follow up.

Purpose Results of allogeneic transplantation in myeloma are controversial. In this trial reduced intensity conditioning matched sibling donor allotransplantation sequentially followingautotransplantation (AutoRICallo) was compared to autografting only in previously untreated multiple myeloma.Patients and Methods 357 myeloma patients up to the age of 69 were enrolled from 2001 to 2005. Patients with an HLA-identical sibling were allocated to AutoRICallo (n=108) and patients without a matched sibling donor to the autotransplant-arm (n=249). Single (n=145) or tandem (n=104) autografting was optional. Conditioning for autologous transplantation was melphalan 200 mg/m2, and for the allograft total body irradiation 2 Gy plus fludarabine 30 mg/m2/day x 3. Median follow-up time was 61 months. Primary endpoint was progression-free survival.Results Progression-free survival at 60 months was significantly better with AutoRICallo (35% vs 18%, p=0.001), as was the risk of death and of relapse in the long term (p=0.047 and p=0.003respectively); at 60 months, overall survival was 65% vs 58%, and relapse incidence was 49% vs 78%. Complete remission rates were 51% and 41%, respectively (p=0.020). Non-relapsemortality at 24 months was 12% after AutoRICallo compared to 3% in the auto-group (p=0.0001). The incidence of grade II-IV acute graft-versus-host disease (GvHD) was 20%, and the incidence of limited and extensive chronic GvHD 31% and 23%.Conclusions In patients with previously untreated multiple myeloma, long-term outcome with respect toprogression-free survival, overall survival and relapse rate is superior after AutoRICallo as compared to autologous transplantation only. Non-relapse mortality is on a reasonable level in both groups.