A prospective PETHEMA study of tandem autologous transplantation versus autograft followed by reduced-intensity conditioning allogeneic transplantation in newly diagnosed multiple myeloma

One hundred ten patients with multiple myeloma ( MM) failing to achieve at least near-complete remission (nCR) after a first autologous stem cell transplantation ( ASCT) were scheduled to receive a second ASCT ( 85 patients) or a reduced-intensity- conditioning allograft (allo-RIC; 25 patients), depending on the human leukocyte antigen (HLA)-identical sibling donor availability. There was a higher increase in complete remission (CR) rate (40% vs 11%, P =. 001) and a trend toward a longer progression-free survival (PFS; median, 31 months vs not reached, P =. 08) in favor of allo-RIC. In contrast, it was associated with a trend toward a higher transplantation-related mortality (16% vs 5%, P =. 07), a 66% chance of chronic graft-versus-host disease and no statistical difference in event-free survival and overall survival. Although the PFS plateau observed with allo-RIC is very encouraging, this procedure is associated with high morbidity and mortality, and therefore it should still be considered investigational and restricted to well-designed prospective clinical trials.