African Americans Underrepresented in Cancer Clinical Trials

Samer Al Hadidi

At a time when many people are talking about equity in health care, research published today in the Annals of Internal Medicine showed just how underrepresented African Americans are in oncology clinical trials.

Samer Al Hadidi, M.D., M.S. and his colleagues at the Baylor College of Medicine computed the “participation-to-prevalence” ratio for clinical trials for 75 cancer drugs approved by the FDA between 2014 and 2018. For the purposes of this study, participation is the percentage of those who enrolled in the trials who are African Americans. The prevalence is the percentage of African Americans among those who have the disease. A participation-to-prevalence ratio of 1.0 would mean that the proportion of African American participants in the clinical trials matches the proportion of African Americans with the disease.

The results reported by Al Hadidi and his colleagues show that, by cancer type, the participation-to-prevalence ratio wasn’t even close to 1.0.

For trials of the nine FDA-approved breast cancer drugs, the participation-to-prevalence ratio was 0.29; for the trials of the eight lung cancer drugs, the ratio was  0.15,  and for trials for the 17 leukemia drugs, it was 0.1. Of the results for the cancer types shown in the study - which the Annals classified as a “brief research report” - multiple myeloma had the lowest participation-to-prevalence ratio at 0.04.

For all the trials lumped together the participation-to-prevalence ratio was 0.31. Of the sum total of the 61,763 people enrolled in the trials included in this study, 7.44% were African American.

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The disproportionate burden of many types of cancer on African Americans is well documented. Data on the HHS Office of Minority Health website show, for example, that the cancer death rate for prostate cancer is twice as high among African American men as it is among non-Hispanic white men (38.9 per 100,000 vs. 18.1 per 100,000). The death rates for African American women are higher than those for white non-Hispanic women for breast, cervical, colorectal, liver, myeloma, pancreas, stomach, and uterine. When all sites are combined, the death rate for African American women is 156 per 100,000 compared with 141.9 for non-Hispanic women, according to the data posted on minority health website.

As the Al Hadidi and his co-authors note, the problem of low African American participation hasn’t gone unnoticed, NIH and others have launched efforts to address. They mention the NIH Revitalization Act of 1993 and the FDA’s “Drug Trials Snapshots.”

They float several ideas for what might be done to increase African American participation, including greater funding for sites that enroll more African Americans and better information about the benefits to the community.