Timing of Autologous Stem Cell Transplantation for Multiple Myeloma in the Era of Current Therapies

Background: Autologous stem cell transplantation (SCT) during the initial treatment of multiple myeloma has been shown to improve progression-free survival (PFS) but not overall survival (OS). While awaiting further prospective data, we retrospectively analyzed the outcomes of patients at our program. Patients and Methods: We included consecutive patients with newly diagnosed myeloma who had undergone stem cell harvest (SCH) from 2005 to 2014 and separated them into early (SCT within 12 months of diagnosis) and delayed (all others, including SCT not yet) groups. The outcomes were OS, PFS to first relapse, and PFS to second relapse. Results: Of the 514 patients who had undergone SCH, 227 were in the early and 287 in the delayed groups. Patients in the delayed group who had undergone SCT had received more therapy before SCT (55% had received ≥ 2 lines vs. 6% in the early group; P <.001), had had more progressive disease at SCT (34% vs. 4%; P <.001), had received melphalan doses < 200 mg/m² (22% vs. 10%; P =.001), and had had lower rates of very good partial response or better after SCT (58% vs. 79%; P =.001). On multivariable analysis, no differences were found in median OS (90 vs. 84 months; P =.093), PFS to first relapse (40 vs. 37 months; P =.552), or PFS to second relapse (54 vs. 52 months; P =.488) between the early and delayed groups. Conclusion: Delaying SCT did not affect OS or even PFS to second relapse in our cohort of patients with newly diagnosed myeloma who had received current era induction therapy.