Consolidation With Second High Dose Therapy and Autologous Stem Cell Transplantation Is Associated With Improved Overall Survival in Patients With Multiple Myeloma in First Relapse.

Background: High dose chemotherapy and autologous stem cell transplantation (HDT/ASCT) remains the preferred first line consolidation strategy for newly diagnosed multiple myeloma (MM). However, The role of HDT/ASCT in first relapse is uncertain in the context of novel therapies. This study evaluates real-world outcomes of MM patients in first relapse, focusing on the role of consolidative HDT/ASCT.

Patients and methods: This retrospective cohort study was conducted at a large tertiary referral center in Northern Netherlands. MM patients who received first-line HDT/ASCT and obtained a good response were included. The time to next treatment or death (TTNT-D 2) and overall survival (OS) were evaluated, while identifying prognostic factors. A landmark analysis was performed at 6 months, including only patients with a partial response (PR) or better after re-induction.

Results: This study identified 237 patients potentially eligible for repeated HDT/ASCT of whom 111 (47%) underwent a second consolidative HDT/ASCT. The median follow-up is 40 months. Baseline characteristics were largely similar, though second HDT/ASCT was applied only after achieving PR or better. In the landmark analysis, absence of high-risk cytogenetics and good performance status were associated with longer TTNT-D 2. Consolidative second HDT/ASCT, absence of high-risk cytogenetics and longer first response duration were associated with longer OS. Transplantation-related mortality rate was < 1%.

Conclusion: This study highlights the viability of second HDT/ASCT as treatment option for relapsed MM, particularly for patients with good responses to first-line HDT/ASCT. In the era of novel agents, second HDT/ASCT should be considered a feasible and effective consolidative strategy.