Impact of Institutional Review Board Type and Food and Drug Administration Diversity Action Plan Draft Guidance on Demographics of Participants Enrolled Clinical Trials Conducted from 2020 to 2024

We assessed participant representation in phase 3 clinical trials registered on clinicaltrials.gov that were conducted in the U.S. between 2020 and 2024. From the 211 clinical trials analyzed, most relied on commercial IRBs (23.2%). Most of the trials in the “unknown” category were sponsored by pharmaceutical companies which likely relied on commercial IRBs. Trials relying on commercial and other/unknown IRBs had the least Black (10.4 −12.1%) and Asian (3.1–3.8%) participation as compared to Academic IRBs which had the highest Black (13.7%) and Asian (9.4%) enrollment (p < .01). Medical Center IRBs had the highest Hispanic enrollment (23.2%) compared to commercial (16.8%) and other IRBs (18.3%). When assessing the impact of the DAP, demographic composition was more varied after the DAP (p < .01). NIH and other sources of funding had greater overall participant representation, by ethnicity and race compared to industry funded trials (p < .01).