If researchers want to know whether a new therapy works, they need to test it in the people most affected by the disease. That sounds obvious. Yet too often, clinical trials fail to do just that.

A recent example highlights the problem. Researchers tested a promising asthma medication called Dupixent in children with moderate-to-severe uncontrolled asthma. The study enrolled more than 400 children ages 6 to 11. Results published in the New England Journal of Medicine showed a 65% reduction in severe asthma attacks compared to a placebo.

Those results sound encouraging. But there’s a major concern.

Ninety percent of the children enrolled in the study were white. Meanwhile, Black and Puerto Rican children experience asthma at much higher rates.

According to the Asthma and Allergy Foundation of America, asthma affects 9.5% of white children. In contrast, asthma affects 18% of Black children and 24% of Puerto Rican children.

In other words, the children most affected by asthma received the least representation in a study designed to evaluate a new asthma treatment.

Who Benefits When Trials Lack Diversity?

Some people may wonder whether race or ethnicity really matters. If a treatment works for one child, shouldn’t it work for another?

Research suggests otherwise.

A study published in the Journal of Allergy and Clinical Immunology found that race and ethnicity influenced the relationship between asthma severity and immunoglobulin E (IgE) levels, an antibody linked to asthma.

Researchers found that elevated IgE levels correlated with worse asthma outcomes in Puerto Rican children. They also concluded that eligibility for asthma biologic therapies may differ across pediatric racial and ethnic groups.

The authors called for more studies that include diverse populations. They argued that researchers must improve representation to ensure equitable treatment for minority patients with asthma.

Unfortunately, the Dupixent study did not meet that standard.

Why Representation Matters in Research

This problem extends well beyond asthma research.

A recent JAMA Network Open study examined vaccine clinical trials and found significant gaps in participant diversity. White participants made up nearly 80% of enrollment. Black participants accounted for only 10.6%, while Latino participants represented just 11.6%.

The disparities appeared in pediatric trials as well. Black children made up just over 10% of participants. Latino children represented 22.5%.

The researchers concluded that vaccine trials in the United States need specific diversity enrollment targets.

The same principle should apply to all clinical trials. Researchers cannot develop truly effective therapies if study populations fail to reflect the communities most affected by disease.

Building Equity Into Every Clinical Trial

At the California Institute for Regenerative Medicine (CIRM), diversity, equity, and inclusion remain central to our mission.

That commitment extends across everything we do. For example, all applicants seeking CIRM funding must submit a written DEI plan.

Our President and CEO, Dr. Maria Millan, recently co-authored an article in Nature Cell Biology that highlighted the urgent need for greater diversity in basic science and biomedical research.

Medical breakthroughs should benefit everyone. To make that happen, research must include everyone.

Diverse clinical trials produce stronger science, better therapies, and more equitable outcomes for patients. That is not just a goal. It is a necessity.