Introduction

Racial and ethnic minorities are underrepresented as participants in urologic oncology research.^1-3 Diversity in clinical trials for drug development is critical to producing externally valid results and building trust between underserved communities and the health care system. The United States Food and Drug Administration (FDA) has acknowledged racial and ethnic disparities in clinical research and encourages more equitable enrollment to address the disproportionate impact of underrepresentation, especially in cancer care.⁴ Several pharmaceutical companies have also committed to more inclusive clinical trial recruitment.^5-7 This study aims to examine trends in racial demographic representation across clinical trial data for urologic oncology drugs approved by the FDA since 2012.

Methods

A review of the FDA Oncology/Hematologic Malignancies Approval Notifications and the Center for Drug Evaluation and Research New Drug Approvals was conducted. Demographic data from registered national clinical trials that the FDA used as evidence to approve oncology drugs for urological indications from January 1, 2012 to December 31, 2022 was aggregated. Participants were categorized into one of 5 racial groups: White, Black, Asian, American Indian/Alaska Native (AIAN), or not reported. The percentage of trials reporting race and each racial group as a percentage of total participants was calculated. Clinical trial data were pooled into 3 chronological groupings (2012-2016, 2017-2019, 2020-2022), and the proportion of each racial group was compared across groups to assess change in demographic composition over time. Trends in racial composition were also analyzed based on the subtype of urological malignancy.

Results and Discussion

A total of 20,578 participants were evaluated across 30 national clinical trials that examined novel treatments for urological cancers and reported at least 1 race associated with their patient population. Fifteen trials focused on drugs for prostate adenocarcinoma, 8 on drugs for renal cell carcinoma, and 7 on drugs for urothelial carcinoma. Significant disparities in representation across races were observed in clinical trials for all urological malignancies and within the 3 subgroups of urological cancers. White individuals were consistently overrepresented compared to all other races. Over time, the percentage of White individuals has decreased while the percentage of all other races has marginally increased (see Figure).

Figure. Racial composition of clinical trial participants for U.S. Food and Drug Administration–approved urological cancer therapies. AIAN indicates American Indian/Alaska Native.

Of the 17 trials in the 2020-2022 cohort, 74.4% of the 9,154 participants identified as White, 3.0% as Black, 15.9% as Asian, 0.4% as AIAN, and 6.3% did not report. Trials focused on drugs for renal cell carcinoma were most skewed toward the overrepresentation of White individuals (Table 1). Of the 10 trials in the 2017-2019 cohort, 76.3% of the 8,746 participants identified as White, 2.6% as Black, 13.8% as Asian, 0.3% as AIAN, and 7.0% did not report. Again, trials focused on drugs for renal cell carcinoma were most skewed toward the overrepresentation of White individuals (Table 2). Of the 3 trials in the 2012-2016 cohort, 88.2% of the 2,678 participants identified as White, 2.5% as Black, 5.0% as Asian, 0.2% as AIAN, and 4.3% did not report. Trials focused on drugs for prostate adenocarcinoma were most skewed toward the overrepresentation of White individuals (Table 3).

Table 1. Clinical Trial Participants by Reported Race for U.S. Food and Drug Administration–approved Urological Cancer Therapies, 2020-2022

Table 2. Clinical Trial Participants by Reported Race for U.S. Food and Drug Administration–approved Urological Cancer Therapies, 2017-2019

Table 3. Clinical Trial Participants by Reported Race for U.S. Food and Drug Administration–approved Urological Cancer Therapies, 2012-2016

The percentage of national clinical trials reporting race has also increased over the last decade. In the 2012-2016 cohort, only 3 out of 8 trials (37.5%) reported race. In the 2017-2019 cohort, 10 out of 14 trials (71.4%) reported race. In the 2020-2022 cohort, 17 out of 19 trials reported race (89.5%). Even fewer of these trials reported ethnicity (ie, Hispanic or Latino, not Hispanic or Latino); the number of trials with information on participant ethnicity was 2 out of 8 (25%), 5 out of 14 (35.7%), and 8 out of 19 (42.1%) for each respective chronological group.

When comparing the 2020-2022 cohort to the 2020 U.S. census data,⁸ the White and Asian populations are considerably overrepresented in clinical trials (74.4% vs 61.6% White, 15.9% vs 6.0% Asian), whereas the Black and AIAN populations are significantly underrepresented (3.0% vs 12.4% Black, 0.4% vs 1.1% AIAN). Although comparison to the U.S. census data is limited by the fact that Americans were able to identify as multiracial (and many did), the stark differences underscore how clinical trial participants in urologic oncology research do not reflect the larger population. This is particularly relevant with respect to therapy for prostate cancer, as Black men have the highest rate of new prostate cancer diagnoses at 164 per 100,000 males compared to 99 per 100,000 males in their White counterparts.⁹ Yet, despite the recognized higher incidence, Black men represented only 4.5% of total participants in the 5 prostate adenocarcinoma clinical trials since 2020.

Unfortunately, racial disparities in clinical trial participation are not unique to drug development for urological cancers; the FDA’s newest guidance for the pharmaceutical industry notes that the underrepresentation of racial minority groups is prevalent across all biomedical research, again despite the known disproportionate burden on these groups for certain diseases.¹⁰

Diversity, equity, and inclusion across races in clinical trials should be a fundamental priority for future research. Collecting data on and reporting race is the first step in achieving this goal. Although narrative information on race and ethnicity in clinical trial participants has improved over time, clinicians and researchers who recruit and oversee these trials must strive to gather this demographic information from 100% of participants. Both the FDA and private pharmaceutical companies must commit to media outreach and public education on the importance of equity in biomedical research. Strategic partnerships with community organizations, meaningful investment in culturally sensitive resources and non-English language materials, and improvements in trustworthy health advocacy can help to mitigate barriers to participation for racial minority groups.

Conclusion

Increased efforts are reducing racial disparities in clinical trials for the development of urologic oncology drugs, but inequitable representation for non-White individuals persists. Lack of inclusion limits the evidence for evaluating the safety and efficacy of innovative drugs for urological malignancies. Clinical trial participation should ultimately strive to reflect the population that will use these treatments. Therefore, enrollment should align with the racial and ethnic makeup of the U.S. population and the epidemiological incidence of these cancers.