Abstract
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).
Keywords
Background
Commercial IRBs review over 70% of U.S. clinical trials for drugs and medical devices. These IRBs tend to have quicker review times which may come at a cost to proper assessment of potential participant harms and inclusion of minority representation.
Methods
We assessed participant representation in phase 3 clinical trials registered on clinicaltrials.gov that were conducted in the U.S. between 2020 and 2024. Participant demographics for analysis included age, sex, ethnicity, and race. Additionally, the IRB name and type used to approve the trial was determined from the consent form, publication, or by e-mail inquiry. IRB types were categorized as academic, commercial, medical center, or other/not reported. We considered our sample size sufficient for descriptive analysis. Chi square tests of independence were conducted to examine the relationship between participant's ethnicity and race by IRB type, along with a comparison of representation before the diversity action plan (DAP) guidance and after. To compare clinical trial enrollment with the U.S. census, one-sample tests of proportions were conducted by sex, ethnicity, and race for all clinical trials combined compared to U.S. census data. Results were considered statistically significant when p < 0.05.
Results
A total of 130,855 participants were enrolled in the 211 clinical trials analyzed. Most study participants were White (70%) and female (54%). Trials were approved by 52 different IRBs. 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).
Limitations:
Many pharmaceutical trials did not provide IRB information. These studies were less representative of the American population similar to studies approved by commercial IRBs. Including IRB information on clinicatrials.gov would provide greater transparency for industry studies. Most studies were conducted in the pre-DAP timeframe, including many COVID-19 related trials, making it difficult to assess the impact of the DAP.
Discussion
The type of IRB of record had an impact on trial participant diversity. With the increased reliance on commercial IRBs and impending single IRB mandate for industry sponsored trials, these results are concerning. One charge of an IRB is that it must ensure justice. IRBs ensure equity and fairness by evaluating inclusion/exclusion criteria, recruitment procedures, and participant selection. It is imperative that all IRBs include review of sample representation as a key component. Executive Order 14151 terminated diversity programs including the DAP. Without a national mandate, the role of IRBs in ensuring trial participant diversity is even more important.
