Clinical trials have historically lacked representation (I.e., they have included exclusively White male patients). When clinical trials do not include patients who represent the diversity of the real-world patient population, it can limit the generalizability of trial results, slow enrollment, and perpetuate health disparities.

The stricter the eligibility criteria, the less diverse the study population becomes, which restricts the ability to apply clinical trial findings to the broader population that will receive treatment outside of the study. For example, if a clinical trial for a new medication only includes participants between ages of 30 and 40 who are in perfect health, the results may not be applicable to older adults are those with existing health conditions who will also use the medication in real-world settings. This restricts the ability to apply clinical trial findings to the broader population that will receive treatment.

The U.S. Food and Drug Administration (FDA) encourages equitable trial enrollment practices aimed at ensuring clinical trials are representative of populations in which a drug is likely to be used upon approval. For instance, FDA issued guidance on planning for representative trials titled, “Diversity Action Plans to Improve Enrollment of Participants from Underrepresented Populations in Clinical Studies; Draft Guidance for Industry.”