Geographic access to ONC201 (dordaviprone) trials for pediatric diffuse midline glioma in the United States: County travel burden and social vulnerability gradients.

Abstract

e14054 Background: ONC201 (dordaviprone) is currently under study for H3 K27M–mutant midline gliomas including pediatric diffuse midline glioma (DMG). We quantified county travel burden to ONC201 study sites and assessed whether access to clinical trials is worse in socioeconomically vulnerable counties and highlighted the need for more equitable access to trial sites across the United States. Methods: From a ClinicalTrials.gov extract, we identified ONC201 studies with U.S. locations (N=5) and extracted site latitude/longitude; sites were de-duplicated to unique coordinates. Cohorts were (1) pediatric-only DMG interventional trial NCT03416530 and (2) pediatric-eligible ONC201 (interventional plus expanded access). For each county centroid (Census Gazetteer), we calculated haversine distance to the nearest site and summarized thresholds (≤100, ≤200 miles). Counties were linked to 2022 CDC/ATSDR SVI (RPL_THEMES) and categorized into national quintiles; population-weighted metrics used county population. Results: NCT03416530 had 8 U.S. locations across 8 states. Median distance to the nearest pediatric-only site was 279 miles (IQR 169–489); 11.0% and 32.2% of counties were within 100 and 200 miles, respectively. The pediatric-eligible cohort included 54 locations (median 109 miles; 45.9% within 100 miles; 80.9% within 200 miles). Access showed a deprivation gradient: median distance increased from 100.1 miles (SVI Q1) to 124.7 miles (SVI Q5), and population-weighted proximity within 100 miles declined from 76.8% to 71.8%. High-vulnerability counties had lower odds of being within 50 miles (SVI Q5 vs Q1 OR 0.30; p<0.001). In SVI Q5, 10.8% (~9.5M of 88.2M) lived >200 miles from the nearest pediatric-eligible site. That high-burden SVI Q5 population was concentrated in the South (59.9%) and West (38.8%), driven by TX (32.1%), NV (23.8%), TN (11.5%), NM (9.5%), and AR (6.0%). Conclusions: Pediatric-only ONC201 DMG trial access is sparse, and socioeconomic vulnerability is associated with reduced proximity even when expanded access sites are included. Regional satellite activation, travel support, and telemedicine-enabled screening may reduce inequities for families affected by pediatric DMG. Our study highlights the emerging need for policy changes that would incentive clinical trial sites to expand access into socio-economically deprived regions for this rare, aggressive pediatric disease.