Assessment of CAR-T clinical trial availability and accessibility in the United States.

1558 Background: Chimeric antigen receptor T-cell (CAR-T) therapy has transformed outcomes in hematologic malignancies and is increasingly evaluated in solid tumors. CAR-T trials requires specialized infrastructure, potentially limiting access by geography and institutional concentration. We assessed the national distribution of CAR-T clinical trials, population distant from trial sites, and institutional clustering. Methods: All active U.S. interventional Phase I-III CAR-T trials (adult/pediatric) were identified via ClinicalTrials.gov (accessed January 2026). Trial locations were geocoded by ZIP code and linked to 2020 Census ZIP Code Tabulation Areas. Population access was defined as residence within 30 or 60 miles of a trial site using Haversine distance. Rurality (RUCA codes), income quartiles, and race/ethnicity (ACS 2023) were evaluated to assess disparities. Institutional concentration was assessed by the proportion of trial sites contributed by individual institutions. Results: Out of 264 identified trials, 189 were selected, conducted across 356 unique institutions. More than 85% of trials were early phase(Phase I–II), spanning lymphoma, myeloma, leukemia, and solid tumor indications. Access was limited. At a 30-mile radius, 43.3% of the U.S. population (~145 million individuals) lacked proximity to an active CAR-T trial site; 27.1% (~91 million) remained without access at 60 miles. Within 30 miles, lack of access affected 94.1% of rural residents, compared with substantially lower coverage in urban areas, and 63.2% of individuals in the lowest income quartile. By race and ethnicity, 37.4% of Hispanic and 32.0% of Black populations lacked access within 30 miles. These patterns were consistent when access was defined at 60 miles. Trial availability was highly centralized. The top 10 of institutions accounted for over 60% of all CAR-T trials, led by large academic centers such as City of Hope, Memorial Sloan Kettering, MD Anderson, Texas Children’s Hospital, and Stanford University. These centers are located in major metropolitan regions, resulting in dense trial availability for populations living nearby while leaving large geographic regions without access. In contrast, approximately 60% of participating institutions hosted only a single CAR-T trial, indicating limited diffusion of trial infrastructure beyond major academic hubs. Conclusions: CAR-T clinical trial access in the United States is restricted by both geographic exclusion and marked institutional concentration. As CAR-T indications expand, addressing these structural bottlenecks will be critical to improving equitable access and ensuring broader participation in cellular therapy development. Access to CAR-T clinical trials. Population Group 30 mi 60 mi Overall US Pop 43.3% 27.1% Rural Pop 94.1% 65.6% Lowest income quartile 63.2% 45.8% Hispanic 37.4% 25.9% Black 32.0% 20.1%