Salvage autologous stem cell transplantation outcomes and the use of maintenance in relapsed multiple myeloma: Real world evidence from the Canadian Myeloma Research Group Database

BACKGROUND: Salvage autologous stem cell transplantation (ASCT2) remains a treatment option for selected patients with relapsed multiple myeloma (MM). In this multicenter study, we conducted a retrospective analysis using the Canadian Myeloma Research Group (CMRG) database to evaluate real-world outcomes of ASCT2 in the maintenance era. PATIENTS AND METHODS: Three hundred and fifty-two patients underwent ASCT2 following progression after ASCT1 between 2012 and 2021. Progression-free survival (PFS), overall survival (OS), depth of response, and the impact of maintenance therapy after ASCT2 were assessed, with further stratification based on maintenance use after ASCT1. RESULTS: Our analysis demonstrated that post-ASCT2 maintenance therapy was associated with improved outcomes, particularly in patients who had also received maintenance after ASCT1 (25.2 months (95% CI, 20.8-39.6) versus 11.6 months (95% CI, 8.51-18.8)). In patients receiving lenalidomide maintenance after ASCT1, a remission lasting less than 3 years represented a high risk group with poor outcomes with an ASCT2. CONCLUSION: While novel agents continue to expand treatment options, ASCT2 remains a viable therapeutic strategy in appropriately selected patients, especially those with durable responses to prior therapy.