The Impact of Underrepresentation of Diverse Groups in Clinical Trials

How does this play out? Here’s one example. Although Black Americans account for about 13.6% of the US population, and 22% of yearly cancer cases, the median enrollment of Black Americans in clinical trials is only about 4.5%, according to a 2020 study on the participation of Black Americans in cancer trials. The impact is serious: for example, Black/African American men are twice as likely to die from prostate cancer, as compared to non-Hispanic white men. Black/African American women are twice as likely to be diagnosed with stomach cancer, and they are 2.3 times more likely to die from stomach cancer, as compared to non-Hispanic white women.

A lack of gender diversity during clinical trials also has a major impact. Men’s health, particularly that of white men, has been studied much more than women’s health in both clinical trial research and general research. One example is the gender differences in heart disease. Men tend to be diagnosed sooner, prescribed medication more often, and treated with medical interventions more often and sooner than women, because the way that heart disease presents in men is much more well understood due to the fact that cardiovascular disease in women has not been studied enough in clinical trials. Yet cardiovascular disease is the number one cause of death in women. Unfortunately, the evidence gap in cardiovascular disease has led to physicians diagnosing and prescribing for women with cardiovascular disease less readily than men. Increased participation of women in clinical studies is one way to close that gap. Go Red for Women, a campaign of the American Heart Association, is also focused on raising awareness of heart health for women through events like National Wear Red Day.

A GSK retrospective study of clinical trial diversity looking at nearly 500 trials with a total of 100,000 participants showed that benchmarking trial diversity against epidemiological data, instead of US Census data, might be more appropriate. The study looked at four diseases — asthma, COPD, HIV and influenza — and results revealed that census data differed from the epidemiological data. For example, while US Census Bureau data indicates 13.6% of the total US population is Black, Black Americans make up 17% of the population with asthma, 7.1% of those with COPD, 55.3% of those with HIV and 23.7% of those with influenza.

Equity in clinical trial participation has lagged far behind other areas of society where attempts have been made to address the issue. The fact that this is still the case in 2023 is shocking, and has serious implications for the health of millions of Americans.

The government agrees, and new legislation has now made representation in clinical trials not just a priority for life sciences companies, but a mandate. A new law that went into effect in late 2022 contains a mandate for the FDA to require trial sponsors to include a diversity action plan in their clinical trials. The goal is to encourage researchers to have a strategy before the trial begins, and ultimately, to understand how drugs being developed will affect a wider population, not just the white men who have historically been clinical trial participants. Starting in 2024, the FDA must publish an annual report in aggregate about the action plans and reasons that trials fell short. How this will work is not yet finalized, and waivers are possible. The FDA released draft guidance in April 2022 on how they think trials should be more inclusive, including setting enrollment goals (not quotas) based on who is affected by the disease being studied. Increasing ethnic representation is the focus, although the new law includes age, sex, geographic location, and socioeconomic status.

Diversifying clinical trials should be a business goal, but now it is mandatory. What challenges do pharmaceutical and biotech companies face when it comes to creating more diverse trials? That’s the subject of our next blog post in the series.