Salvage Autologous Stem Cell Transplantation in Relapsed/Refractory Multiple Myeloma: Long-Term Efficacy and Safety Outcomes from a Single-Center Real-World Cohort

Background: The role of salvage autologous stem cell transplantation (ASCT) in relapsed/refractory multiple myeloma (R/R MM) is being reconsidered in the era of novel immunotherapies. We evaluated the long-term efficacy and safety of salvage ASCT in a real-world single-center cohort. Methods: We retrospectively analyzed 57 patients with R/R MM who underwent salvage ASCT between March 2012 and August 2025. Clinical characteristics, treatment responses, toxicities, progression-free survival (PFS), overall survival (OS), and prognostic factors were assessed. Results: The mean age at salvage ASCT was 60.2 ± 8.2 years. Before salvage ASCT, 50.9% of patients achieved complete response or very good partial response, increasing to 80.7% by day +100. Transplant-related mortality was 3.5%, while infection or febrile neutropenia occurred in 77.2%. Median PFS and OS after salvage ASCT were 34.0 months (95% CI, 28.8–39.2) and 67.2 months (95% CI, 46.2–88.2), respectively. Median OS from diagnosis was 130.5 months. In multivariate analysis, higher LDH and pre-transplant refractory status were independently associated with PFS, whereas age at salvage ASCT and beta-2 microglobulin level were independently associated with OS. Conclusions: Salvage ASCT was associated with durable disease control and acceptable transplantation-related outcomes in this carefully selected cohort. Its comparative role relative to contemporary immunotherapies requires prospective evaluation.