Clinical Practice of Treatment Switch in Transplant-eligible Patients with Multiple Myeloma: An Exploratory Retrospective Analysis.

Objective In the real-world clinical setting of transplant-eligible patients with multiple myeloma (MM), a certain proportion of patients switch from induction therapy to other regimens because of insufficient response or adverse events. However, the prognostic benefits of these changes remain unclear. This retrospective study investigated the impact of pre-transplant induction therapy switches on the prognosis. Methods We analyzed the treatment course, patient background, risk classification, and post-transplantation event-free survival (EFS) of 35 patients who achieved partial response or better with triplet therapy and underwent autologous stem cell transplantation (ASCT) at our institution between January 2017 and July 2023. Results Induction therapy included VRd therapy in 11 patients and switching therapy in 20 patients (7 due to intolerance and 13 due to insufficient treatment effects). Among the 13 patients who switched treatment due to insufficient treatment effects, 10 showed an improved response, leading to a trend towards a better EFS. Nevertheless, high-risk chromosomal abnormalities, particularly t (4;14), were associated with a significantly poorer EFS, regardless of the treatment received. Conclusion Even with a response-guided induction treatment switch, maintaining long-term remission after ASCT in high-risk patients remains challenging. A careful risk assessment using fluorescence in situ hybridization or a genomic analysis may improve the prognosis of patients with MM in the future.