P-331: ASCT: A Viable First-Line Treatment Option for Elderly Multiple Myeloma Patients Without Access to New Drugs

Introduction: The standard first-line therapy for multiple myeloma (MM) involves induction therapy combined with autologous hematopoietic stem cell transplantation (ASCT). While no guidelines explicitly recommend against ASCT based on age, many centers typically set a cutoff at 65 years for this treatment.

Methods: We conducted a retrospective analysis at Beneficência Portuguesa of São Paulo on patients with multiple myeloma (MM) who underwent autologous hematopoietic stem cell transplantation (ASCT) between 2016 and 2023. The study focused on patients over 65 and included a sub analysis of patients over 70. We analyzed progression-free survival (PFS) and overall survival (OS).

Results: We included 136 patients aged 65 and older in our study, of whom 39 were over 70. The one-year, two-year, and three-year progression-free survival (PFS) rates were 80%, 67%, and 53%, respectively, with a median PFS of 3.3 years. In a subanalysis by conditioning regimen (melphalan 200mg/m², melphalan 140mg/m², melphalan 100mg/m² and BuMel), no significant differences in PFS were observed after two years. However, in one year, patients who received a Melphalan 200 mg/m² conditioning regimen had a PFS of 83%, compared to 74% for those on a less intensive regimen Mel 140 mg/m² and Mel 100mg/m². The median overall survival (OS) in proven population were 86.4% in the first year, 80.3% at the second year, and 74.1% at the third year. Our sub analysis revealed no significant differences in OS between patients under and over 70 years old regardless of conditioning regimen.

Conclusions: This study provides a real-world perspective on the safety and survival benefits of ASCT in the elderly population. The overall survival (OS) and progression-free survival (PFS) rates observed are comparable to those in younger age groups studies. Currently, ASCT remains a viable treatment option for elderly patients and should be reevaluated in the future as newer therapies, such as CAR-T cells and bispecific drugs, become more established. This study provides a real-world perspective on the PFS and OS benefits of ASCT in the elderly population where the results are comparable modern protocols with combined drugs in young patients (MAIA and SWOG S0777). The ASCT in this population can be beneficent in first line therapy as new protocols are unavailable.