Pivotal Trials Will Address Diversity With New FDA Initiative

NEW YORK — Underrepresentation by gender and race in major clinical trials has been a cause for complaint for decades, but the US Food and Drug Administration (FDA) has drafted a regulatory solution to this issue expected to be implemented sometime in 2025.

This initiative, known as the FDA’s Diversity Action Plan (DAP), will require plans for all pivotal and phase 3 trials to provide details in their design of how diversity will be achieved or, if there are no plans for diversity, the reason why, according to Valerie M. Harvey, MD, MPH, associate clinical professor, Edward Via College of Osteopathic Medicine, Blacksburg, Virginia. These rules will be codified, she said at the 2024 Skin of Color Update.

Once the DAP is enacted, “the sponsor must specify the rationale and goals for study enrollment by age, ethnicity, sex, and race,” she said. Furthermore, the submission to the FDA must “describe the methods to meet the diversity benchmarks.”

Lack of Trial Diversity Is Common Across Medicine

Although she focused on the relevance of this initiative to dermatology, Harvey said the lack of diversity in clinical trials is pervasive throughout medicine. In one survey of randomized controlled trials, less than 60% of trials even specified the race and ethnicity of the participants. In recent psoriasis trials, only 30% met a diversity definition of ≥ 20% of patients identifying as minority (Black, Hispanic, Asian, or other non-White group), said Harvey, who practices dermatology in Newport News, Virginia.

The FDA draft guidance for DAP was released in June 2024 and is now available for submitting comments (until September 26). The plan is expected to be published in June 2025, according to Harvey. It will pertain to all pivotal and phase 3 trials enrolling 180 days after the publication date and will be relevant to all drugs and biologics as well as certain devices.

This initiative could be a critical step toward ensuring diversity in major clinical trials after years of stagnation. Harvey said, noting that despite repeated calls for more diversity in clinical trials, the literature suggests “little progress.”

However, she said that increasing diversity in clinical trials is just one step toward gathering data about the generalizability of efficacy and safety across racial and ethnic groups. A much more complex issue involves how race and ethnicity are defined in order to understand differences, if any, for efficacy and risk.

“Race is a dynamic social construct and a poor measure for biologic variation and skin color,” Harvey said. This means that work is needed to address the more complex issue of race and ethnicity stratification that will help clinicians understand the relative benefits and risks for the drugs in these trials.

Rather than differences based on genetic or other sources of biologic differences, she said, outcomes by race alone are often suspected of reflecting disparities in access to healthcare rather than a difference in therapeutic response.

Skin Color Is Inadequate to Define Race

When stratifying patients by race or ethnicity, Harvey said that “we have to be very, very careful in considering the study purpose and what the study question is.” A study attempting to compare benefits and risks among subgroups by race or ethnicity will require descriptors beyond skin color, she added.

The recognized limitations of measuring skin tone as a surrogate of race are one reason for widespread interest in moving away from the Fitzpatrick skin type (FST) rating that has been widely considered a standard, according to Harvey. Several alternatives have been proposed, including the Monk Skin Tone Scale, the Individual Typology Angle, and the Eumelanin Human Skin Color Scale, but she cautioned that these are less well validated and generally have the limitations of the FST.

If skin color was ever useful for grouping individuals on the basis of shared physiology, growing rates of intermarriage and immigration have made skin color increasingly irrelevant to racial identity. If the goal is to evaluate the safety and efficacy of drugs across racial groups and ethnicities, the characterization of populations will almost certainly require multiple descriptors and biomarkers, she said.

“It is very important to have many tools for characterizing patients by skin type,” Susan Taylor, MD, professor of dermatology and vice chair for diversity, equity, and inclusion for the Department of Dermatology, University of Pennsylvania, Philadelphia, said at the meeting.

The reason is “there are limitations to all of them,” she said, noting also that the questions being asked about how and if skin color and race are relevant to therapeutic options differ by the question, such as innate response or access to care.

Taylor is part of a workshop that she said is evaluating a combination of instruments for characterizing skin color and race in ways relevant to the specific question being asked.

The solutions might differ. While simple clinical assessments involving skin color might be made with methods captured on a smartphone app, Taylor acknowledged that far more complex tools might be required to document the effect of racial or ethnic differences in drug efficacy and safety in a research setting.

Outside of a research setting, any tools that might be useful for assessing race as a variable must be practical, according to Harvey. She suggested that these must be time efficient, of reasonable cost, and most importantly, reliable.

Tools meeting these criteria do not currently exist, but Harvey said the work is underway. She expects a “top-down” collaborative approach to validate alternatives to the FST. If such tools can be developed with buy-in from the FDA, they might be particularly useful for translating trial data to patient care, she added.

Harvey reported financial relationships with AbbVie, Bristol Myers Squibb, Janssen, Johnson & Johnson, L’Oréal, and SkinCeuticals. Taylor, president-elect of the American Academy of Dermatology, reported financial relationships with more than 25 pharmaceutical and cosmetic companies.

Ted Bosworth is a medical journalist based in New York City.