(PA-405) Nuanced Treatment Decision for Newly Diagnosed Multiple Myeloma Patients Between 65-75 Years Old

Introduction:  Multiple myeloma (MM) is a clonal plasma cell malignancy that accounts for approximately 10% of all hematologic cancers. While MM has always been a disease of older adults, the median age at diagnosis is slowly increasing, paralleling trends in population aging. Recently, DETERMINATION trial reaffirmed the role of autologous stem cell transplantation (ASCT) as part of frontline therapy, offering significant progression-free survival (PFS) benefits for patients aged 65 years or younger. While age 65 has traditionally served as a threshold for transplant eligibility, it lacks biological or clinical justification.
This study aims to evaluate contemporary treatment patterns and outcomes in newly diagnosed MM patients aged 65 to 75 years. By comparing patients aged < 70 and ≥70 years, we seek to characterize differences in treatment selection, transplant utilization, and clinical outcomes, thereby informing a more tailored approach to treatment planning in this key population.

Methods:   This is a longitudinal cohort study conducted between January 2015 and December 2023 at 2 academic centers. A total of 561 patients aged between 65 years and 75 years at MM diagnosis were retrospectively identified and included. Their medical records were reviewed and analyzed for demographics, baseline disease characteristics, details of treatment, treatment outcomes, and survival.

Results:   Patients were categorized into 4 groups: Group 1 age 65-69 + ASCT (N=183); Group 2 age 65-69 + no ASCT (N=133); Group 3 age 70-75 + ASCT (N=15); and Group 4 age 70-75 + no ASCT (N=230). There were no differences between the 4 groups with regards to ISS stage, risk status and basline laboratory results. Triplet regimen was most often used across all groups. Interestingly, about 1/4 of patients in both Group 2 and Group 4 were treated with doublet regimen. ASCT was associated with associated with improved PFS regardless of age (Group 1 39.1M vs Group 2 17.3M vs Group 3 24.2 months vs Group 4 20.7 months). For patients between 65-70, this trend translated into overall survival gain (P< 0.001), but for patients between 70-75 PFS gain did not lead to overall survival gain (P=0.102). Quadruplet regimens demonstrated significantly longer PFS compared to triplet or doublet regimens across all groups.

Conclusions:   Upfront ASCT offers PFS gain for newly diagnosed MM patients upto 75 years old.