Center-level delivery patterns and capacity during rapid CAR-T expansion in the United States (2021-2023).

Abstract

11089 Background: Chimeric antigen receptor T-cell (CAR-T) therapy has rapidly expanded in the United States, accompanied by substantial growth in utilization and expenditures. However, whether this expansion has been matched by proportional growth in delivery capacity and how CAR-T workload is distributed across centers remains unclear. Methods: We conducted a national retrospective analysis using publicly available Medicare administrative data from 2021-2023 obtained from the Medicare Inpatient Hospitals dataset on data.cms.gov. CAR-T hospitalizations were identified using the diagnosis-related group (DRG) descriptions for CAR-T therapy and other immunotherapies. Active CAR-T centers were defined annually based on inpatient discharges. This DRG-based approach may include non-CAR-T immunotherapies, and Medicare data captures primarily older adults, potentially missing younger patients with acute lymphoblastic leukemia and lymphoma. Center-level CAR-T volume and expenditures were aggregated annually. Per-center delivery burden was assessed by strain (total CAR-T discharges divided by number of active centers). Concentration of CAR-T delivery across centers was evaluated using cumulative contribution analyses. Results: From 2021 to 2023, active CAR-T centers increased from 23 to 46, while total CAR-T discharges rose from 544 to 1,303. Total annual CAR-T expenditure increased substantially over the same period, from $728 million in 2021 to $2.56 billion in 2023. Despite this expansion, median annual discharges per center remained relatively stable (24 in 2021 vs 25.5 in 2023), while mean discharges increased from 23.7 to 28.3, indicating that growth was driven disproportionately by higher-volume centers. Correspondingly, the center-level strain increased from 23.6 to 28.3, reflecting rising per-center delivery burden. CAR-T delivery remained moderately concentrated across years, with top quartile of centers (approximately 21.7% of centers) accounting for 37.3% of CAR-T discharges in 2021, increasing to 39.5% of discharges in 2023. Conclusions: Despite rapid expansion in CAR-T centers and substantial growth in utilization and expenditures, delivery is increasingly concentrated among higher-volume centers. Stable median per-center volumes alongside increasing mean volumes and persistent concentration patterns suggest that growth has outpaced effective distribution of delivery capacity. While the relationship between center volume and patient outcomes remains incompletely characterized, these findings highlight the need for workforce development, infrastructure investment, and policy strategies to support both high-volume centers experiencing rising delivery burden and lower-volume centers developing expertise, ensuring sustainable and equitable CAR-T delivery as utilization continues to expand.