Impact of New Drugs on the Long-Term Follow-Up of Upfront Tandem Autograft-Allograft in Multiple Myeloma

Before the introduction of “new drugs,” we designed a trial in which 162 newly diagnosed myeloma patients were biologically randomized to receive either an autologous stem cell transplant (auto-SCT) followed by a nonmyeloablative allogeneic stem cell transplant (allo-SCT) or a double auto-SCT. Fifty-eight patients in the allo-SCT arm and 46 in the double auto-SCT arm completed the assigned treatment. At a median follow-up of 12.3 years from allo-SCT and 12.1 years from second auto-SCT, median overall survival (OS) was 11.4 in the allo-SCT arm and 3.9 years in the auto-SCT -arm (P = .007), whereas event-free survival was 3.6 and 1.5 years (P < .001), respectively. A subset of allo-SCT patients showed persistent molecular remission. Two-year cumulative incidence of chronic graft-versus-host disease was 67.2%. At 5 years, 39% of these patients were alive, disease-free, and off immunosuppression; 36.6% had relapsed and 12.2% were still on immunosuppression. Thirty-three of 58 patients (allo-SCT arm) and 39 of 46 (auto-SCT arm) relapsed at least once and were rescued with new drugs. In the allo-SCT arm, 2 patients in biochemical relapse did not reach clinical criteria for treatment. Overall 28 (90%) were treated with new drugs and 14 (45%) received donor lymphocyte infusions (DLIs). In 28 of 31 patients (90%) DLIs were given with new drugs. Median OS from first relapse was 7.5 years in the allo-SCT arm and 2 years in the auto-SCT arm (P = .01). Patients who received DLI showed significantly longer OS (hazard ratio, .38; P = .042) as compared with auto-SCT patients. This difference was slightly lower when only allo-SCT patients who did not receive DLIs were considered (hazard ratio, .56; P = .154). In summary, long-term disease-free survival and survival outcomes after treating relapse with new drugs with or without DLIs were better in allo-SCT patients.