2127 - Assessing Compliance and Diversity in Early Phase Radiation Oncology Clinical Trials in the United States

A. Rezaei¹, A. T. Price², S. McClelland III³, and L. E. Henke²; ¹University Hospitals, Seidman Cancer Center, Case Western Reserve University, Cleveland, OH, ²Department of Radiation Oncology, University Hospitals Seidman Cancer Center, Case Western Reserve University, Cleveland, OH, ³Case Western Department of Radiation Oncology, Cleveland, OH

Purpose/Objective(s): Racial and ethnic minority populations are underrepresented in cancer clinical trials, with significant barriers more pronounced in these groups. The US Food and Drug Administration (FDA) recommends the inclusion of underrepresented racial and ethnic populations and provides a standardized approach for collecting and reporting race and ethnicity data. This study aims to evaluate compliance with this recommendation and the distribution of national accrual among different race/ethnicity groups in early phase radiation oncology clinical trials. Materials/

Methods: We searched the clinicaltrials.gov database for registered interventional clinical trials over a 10-year period, including those started on or after January 1, 2014, and completed by January 1, 2024. The intervention for all included trials was "radiation therapy" without further specification. Other inclusion criteria were adult age >18 years, study phase = "early phase 1" or "phase 1," study type = "interventional," funder type = "NIH" or "industry," and trial location = "United States." The data were screened to remove irrelevant information before analysis. Participants were recategorized as: non-Hispanic black (NHB), non-Hispanic white (NHW), Asian, Hispanic, and Others. Data were reported using descriptive statistics, with confidence intervals (CIs) for rates calculated using the binomial exact distribution and a significance level set at <0.05.

Results: Out of 215 clinical trials that met the search criteria, 172 were related to radiation oncology interventions. Of these, 105 (61.4%) were completed before January 1, 2024 (the rest were terminated or withdrawn). Results for 86 (81.9%; 95%CI 73.2-88.7) clinical trials were published; of these, 39 (45.3%; 95%CI 34.6-56.4) were in peer-reviewed journals and 47 (54.6%; 95%CI 43.5-65.4) were only published as abstracts at scientific meetings. Of the 86 published clinical trials, only 16 (18.6%; 95%CI 11.0-28.4) reported the racial distribution of study participants per FDA recommendations. Of the 432 subjects enrolled in these 16 studies, 213 (49.3%; 95%CI 44.5-54.1) were male and 219 (50.7%; 95%CI 45.9-55.5) were female. The racial/ethnic distribution was as follows: 32 (7.4%; 95%CI 5.1-10.3) NHB, 317 (73.4%; 95%CI 68.9-77.5) NHW, 11 (2.5%; 95%CI 1.3-4.5) Hispanic, 7 (1.6%; 95%CI 0.6-3.3) Asian, and 65 (15.0%; 95%CI 11.8-18.8) Others.

Conclusion: Less than 20% of early phase clinical trials in radiation oncology complied with the FDA’s recommendations for the collection and reporting of race and ethnicity data. Moreover, the lack of racial and ethnic diversity in early phase radiation oncology clinical trials has persisted over the past decade, necessitating immediate interventions to address this disparity.