The number of unique clinical trial sites in the United States with phase I studies for patients with non–small cell lung cancer (NSCLC) decreased by 44% from 2020 to 2024, showing a significant consolidation of studies to only high trial volume sites in the country, according to the results of a quantitative study presented at the American Association for Cancer Research (AACR) Annual Meeting 2026 (Abstract 1395).
"This analysis demonstrates a concerning trend towards trial consolidation at top performing sites in the U.S., further supporting concerns regarding site saturation and conflicting with appeals to decentralize and move trials into the community," the study authors noted in their abstract.
Background and Study Methods
The U.S. Food and Drug Administration (FDA) has placed regulatory importance on bringing clinical trials closer to where patients are living throughout the United States and to increase clinical trial enrollment so that trial results are more accurately representative of the overall U.S. patient population. The Oncologic Drugs Advisory Committee has also noted that trial site saturation and distribution is another issue impacting clinical trial enrollment.
“It is imperative that clinical trial populations reflect as closely as possible the end-user population to sufficiently determine a therapy’s safety and efficacy and inform its optimal use,” said presenting author Brittany Avin McKelvey, PhD, the Senior Director of Regulatory Policy at LUNGevity Foundation. “Therefore, a better understanding of where clinical trials are being conducted, and how the participation of trial sites changes over time, can ensure that we support policies that encourage representativeness and applicability of trial results to the U.S. population.”
Researchers from the LUNGevity Foundation examined the distribution of global clinical trial sites, using lung cancer trials as an example to understand recent trends. They completed a quantitative descriptive assessment of interventional, industry-sponsored phase I clinical trials for NSCLC within and outside of the United States over time. They searched ClinicalTrials.gov data to find early phase I or phase I trial openings between 2020 and 2024.
In the study, a trial instance was defined as the initiation of a unique trial at a unique site.
Key Findings
For the study period, a total of 555 phase I trials in NSCLC were opened for a total of 8,393 trial instances in 47 countries. The most common trial sites were in the United States (45%) followed by China (11%).
The number of trial openings increased over the study period, but the number of unique trial sites and trial instances, both internationally and within the United States, decreased starting in 2022 and through 2024.
"Our analysis showed a concerning trend towards trial consolidation at top-performing sites in the United States, further affirming concerns raised at the recent FDA ODAC meetings about site saturation and conflicting with the agency’s appeals to decentralize and move trials into the community,” Dr. McKelvey said. “This geographically concentrated clinical trial landscape may result in more limited access to clinical trials.”
In the United States, trial sites with at least one trial opening decreased significantly from 395 sites with an initiating trial in 2020 to 223 sites in 2024. Sites with the highest trial volume, the top 20 sites, did not see any decrease over this time period; the top 20 sites had at least 27 trials opening in this study period.
“The competitive oncology landscape for trial enrollment may favor established sites with proven track records, creating a self-reinforcing cycle where high-performing sites attract more trials, develop greater expertise, and become increasingly preferred by sponsors—while lower-volume sites struggle to maintain the infrastructure and expertise needed to compete for trials,” Dr. McKelvey said.
“This could suggest that the infrastructure support and integration into research networks at [National Cancer Institute (NCI) Community Oncology Research Program (NCORP)] sites may be able to buffer these community sites against the factors driving consolidation,” Dr. McKelvey said. “Overall, addressing this consolidation and ensuring identification of the appropriate sites for clinical research will require coordinated efforts to reduce site activation barriers, provide infrastructure support, and potentially implement policy incentives that encourage diversification of trial portfolios within the United States.”
DISCLOSURES: This study was funded by LUNGevity Foundation through unrestricted grants. Dr. McKelvey declared no conflicts of interest. For full disclosures of the other study authors, visit abstractsonline.com.
