Black Americans make up 13% of the US population and carry a disproportionate burden of certain cancers, cardiovascular disease and diabetes. In clinical trials, they account for roughly 5%.¹ Non-Hispanic white Americans, at approximately 61% of the population, represent more than 90% of trial participants in some therapeutic areas.²

That gap is not just a question of fairness. It is a scientific problem with measurable consequences: drug metabolism, disease presentation and treatment response all vary by ancestry, genetics and the social and environmental conditions that shape health over a lifetime. Trials that do not reflect the people who will use a treatment produce evidence that is harder to generalise and less useful in clinical practice.

Juneteenth, observed on 19 June, marks the day in 1865 when freedom was finally delivered to people it had long been promised to. It is a reminder that inclusion does not happen by default. It has to be built, deliberately, into the systems that shape people’s lives. Clinical trials are one of those systems, and one the research industry has the power to change.

The vaccine trial that paused to get it right

The COVID-19 vaccine programme showed what happens when the gap is caught early. When enrollment data for one major trial revealed Black Americans made up approximately 7% of participants, the sponsor paused recruitment, actively enrolled more participants from under-represented communities and then proceeded. That decision strengthened the ability to interpret safety and efficacy data across a broader population.³

It also demonstrated something important: the problem responds to deliberate action.

Four approaches that work

Published evidence supports a set of practical changes, increasingly standard in well-designed inclusive trials.

• Put trials where patients are. Placing studies in community hospitals and federally qualified health centres broadens the enrollment pool before a single participant is recruited. The ASCO-ACCC Joint Research Statement identified site selection and community-centred trial infrastructure as key levers for reducing barriers to diverse participation.⁴

• Reduce the travel burden. Decentralised trial designs that allow remote or local-clinic participation remove one of the biggest barriers for under-represented communities. WCG data shows that trials incorporating inclusive designs report a 30% higher retention rate among diverse populations.⁵

• Go to the community, not the other way around. Embedding researchers in churches, civic organisations and community spaces reaches populations that academic centres routinely miss. One NIH-supported programme at the Eastern Virginia Medical School engaged more than 1,700 people across 45 community events in Hampton Roads, including health fairs, civic events and talks at Black churches, as part of outreach for the AHEAD Alzheimer’s study.⁶

• Fix the protocol, not the pipeline. Eligibility criteria that exclude patients with common comorbidities reduce diversity before recruitment begins. In one analysis, 60% of study eligibility criteria in oncology trials were directly related to comorbidities or performance status; when those conditions are more prevalent in specific populations, demographic disparities in enrollment follow.⁷ Addressing this at the design stage is more effective than trying to correct it downstream.⁸

What better data looks like

Approvals based on more representative populations carry stronger evidence of safety and efficacy across the full range of patients who will use those treatments. Differences in drug response between population groups are more likely to be identified, understood and reflected in labelling, dosing and prescribing decisions.

The regulatory direction supports this. The US Food and Drug Administration’s diversity action plan requirements under FDORA (2022) signal a structural shift toward requiring sponsors to demonstrate how their trials will reflect the populations most affected by a disease, though the timeline for final enforcement guidance remains subject to change.⁹

WCG data and broader trends suggest that meaningful progress is achievable within a single decade when the right conditions hold: community engagement, decentralised design, protocol criteria that reflect real patient populations and a research workforce that increasingly represents the communities it serves.⁵

Where TFS fits

TFS HealthScience runs clinical research across 40 countries in oncology, neuroscience, dermatology and internal medicine. The decisions that shape how broadly a trial can reach, and how meaningful its findings turn out to be, happen early: at protocol design, in site selection, in eligibility criteria and in community engagement strategy.

We work with sponsors to build those considerations in from the start rather than retrofitting them later. That work is operational and methodological, and it creates value at every stage of a programme.

Juneteenth reminds us that inclusion is worth pursuing with intention. In medicine, that means science built to reflect the full diversity of the patients it serves.

Editorial note: This article is for informational purposes only and reflects a summary of publicly available information. It does not constitute scientific, medical or regulatory advice, nor does it endorse any investigational product. All data are sourced from published or institutional research; figures may vary by indication, geography and methodology. TFS HealthScience was not a sponsor or investigator in any studies referenced.

Sources

1. Alegria M et al. (2021), as cited in Alsan M et al., “Investigator racial diversity and clinical trial participation,” Journal of Health Economics, 2025. Also: National Cancer Institute, “Black Patients’ Beliefs About Clinical Research,” 2024. cancer.gov
2. Coakley M et al., “Minority Representation in Clinical Trials in the United States,” Mayo Clinic Proceedings, 2021. mayoclinicproceedings.org
3. Harvard Medical School, “Embracing Diversity: The Imperative for Inclusive Clinical Trials.” learn.hms.harvard.edu
4. Oyer RA et al., “Increasing Racial and Ethnic Diversity in Cancer Clinical Trials: An ASCO and ACCC Joint Research Statement,” Journal of Clinical Oncology, May 2022. ascopubs.org
5. WCG, 2025 Trends & Insights Report: Diversity in Clinical Trials, January 2025. wcgclinical.com
6. “Faith-Based Community Outreach to Increase Alzheimer’s Clinical Research Participation in the Black Community,” Alzheimer’s & Dementia / NIH NCBI, 2023. ncbi.nlm.nih.gov
7. Riner AN et al., “Eligibility Criteria Perpetuate Disparities in Enrollment and Participation of Black Patients in Pancreatic Cancer Clinical Trials,” Journal of Clinical Oncology, 2022; editorial: “Clinical Trial Eligibility Criteria: A Structural Barrier to Diversity,” JCO, 2022. ascopubs.org
8. Al Hadidi S et al., “Participation of Black Americans in Cancer Clinical Trials: Current Challenges and Proposed Solutions,” JCO Oncology Practice, 2021. ascopubs.org
9. US FDA, “Diversity Action Plans to Improve Enrollment of Participants from Underrepresented Populations in Clinical Studies,” draft guidance, June 2024; mandated under FDORA Section 3601 (2022). fda.gov