Association between survival outcomes in patients with multiple myeloma and treatment facility volume.

7529 Background: Oncology research previously demonstrated a volume-outcome relationship, where patients treated at healthcare centers with higher (vs lower) treatment volumes have improved survival. In multiple myeloma (MM), evidence supporting this association remains limited. Most patients with MM are treated at lower volume centers; it is important to recognize and prioritize partnerships between higher and low-volume centers. Methods: Adults (≥18 years) receiving ≥1 active MM therapy—IMiD, PI, anti-CD38 mAb, CAR-T, ASCT—from 2017 - 2023 with ≥6-month pre-index enrollment were identified in Komodo Health’s Healthcare Map. Patients lacking facility data or treated outside their diagnosing site were excluded. Facilities were segmented based on volume, defined as the average number of new patients with MM per year: ≤1 (very low), 1–5 (low), >5–10 (medium volume), >10 (higher volume). Outcomes included overall survival (OS) and event-free survival (EFS), the latter separately defined as time to 1) therapy change and 2) first symptomatic progression (based on CRAB criteria). Multivariable mixed-effects Cox models were adjusted for diagnosis year, demographics, comorbidities, payer type and treatment exposure. Subgroup analysis of patients initiating 2L therapy was also conducted. Results: 18,646 MM patients and 2,049 facilities were identified. Volume distribution was highly skewed: 81.0% were treated at very low volume centers and ~1.9% were treated at higher volume centers. Higher volume centers had the highest use of ASCT (63.7%) and CAR-T (2.1%). Among all patients, use of IMiD-, PI-, and anti-CD38–based regimens were 51.42%, 63.55% and 35.69%, respectively. Although median OS was not reached for any of the segments, higher volume centers had the highest unadjusted median EFS using therapy-based (771 days) and CRAB-defined progression (213 days) definitions (p<.001 vs all other segments). After adjustment, lower-volume segments (very low, low and medium volume centers) had shorter median OS (HRs: 1.03-1.26, 95% CI 0.88-1.46) than higher volume centers. However, compared with higher volume centers, median EFS was similar in lower-volume segments (HRs: 0.97-1.09, 95% CI 0.86-1.23). Among 2L patients, OS models and CRAB-defined EFS showed similar volume-related patterns compared with adjusted overall results. Conclusions: Higher-volume centers had more experience with novel therapies and combination of therapies. Experience from high volume centers can effectively be used to partner with smaller volume centers to advance MM care and be able to improve outcomes for patients. Adjusted EFS and OS hazard ratios by treatment facility segment. Change in Therapy EFS OS Facility Volume Segment Overall 95% CI Overall 95% CI Higher volume Ref Ref Ref Ref Medium volume 0.97 (0.86, 1.09) 1.03 (0.88, 1.21) Low volume 1.03 (0.92, 1.16) 1.15 (0.99, 1.34) Lower volume 1.09 (0.97, 1.23) 1.26 (1.09, 1.46)