This Genetic Difference Is Unfairly Keeping Black Americans Out of Clinical Trials

Racial disparities in cancer outcomes are a serious problem, and they begin with clinical trial access. Studies show that people of color, especially Black Americans, are more likely to die from cancer than white people. One reason is that they often don’t have the same access to treatment or clinical trials.

These trials are the bedrock of medical advancement, developing new therapies and improving existing ones. When certain demographic groups are underrepresented, the efficacy and safety of new treatments may not be fully understood across all populations, perpetuating and even exacerbating existing health inequities.

A 2024 study published in JAMA brought to light a critical, often overlooked genetic difference that disproportionately affects people of color: Duffy null-associated neutrophil count (DANC). DANC is a genetic variant more prevalent in individuals of African and Middle Eastern descent, leading to a naturally lower-than-average white blood cell count. Importantly, this lower count does not indicate compromised health or immune function in individuals with DANC.

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The JAMA study meticulously examined clinical trials for five of the most common cancers: breast, prostate, lung, colorectal, and melanoma. The findings were stark: a staggering 76.5 percent of these trials systematically excluded individuals with DANC. This exclusion occurred despite their white blood cell counts being within what is considered a healthy range for people with this genetic variation. The root of this problem lies in the reliance on outdated guidelines that fail to account for the physiological differences associated with DANC. These guidelines, often developed without sufficient representation from diverse populations, create an unintended but very real barrier to trial participation for a significant portion of the population.

Furthermore, the study uncovered another concerning revelation: 53.5 percent of cancer treatment regimens recommended lower doses for patients with DANC. This practice, driven by an assumption that lower white blood cell counts equate to a compromised immune system, can lead to suboptimal treatment and potentially less effective outcomes for these patients. By not adjusting for DANC, medical professionals may inadvertently be under-treating individuals who could safely tolerate and benefit from standard or even higher doses.

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The researchers unequivocally state that these findings underscore a profound unfairness in current cancer treatment guidelines for individuals with DANC. Their recommendation is clear and urgent: clinical trials and treatment regimens must be updated to explicitly account for DANC. Implementing this change is not merely a matter of fairness; it is a critical step towards reducing racial disparities in cancer outcomes and ensuring that everyone has an equitable chance at receiving optimal, life-saving care.

The underrepresentation of Black individuals in clinical trials is a multifaceted issue, stemming from historical mistrust, socioeconomic barriers, and a lack of targeted outreach. However, their participation is vital for several key reasons:

• Ensuring Treatment Efficacy and Safety for All: When clinical trials lack diversity, the data collected may not accurately reflect how a new drug or treatment will perform in different racial and ethnic groups. Genetic variations, metabolic differences, and varying disease presentations can influence a drug’s effectiveness and side effects. For example, some medications are metabolized differently based on genetic factors, which can vary across racial groups. Without Black participants, researchers cannot fully understand these nuances, potentially leading to treatments that are less effective or even harmful for this population.
• Identifying and Addressing Racial Disparities: The JAMA study on DANC is a prime example of how increased participation and targeted research can uncover hidden biases and physiological differences that contribute to disparities. If Black individuals are not adequately represented in trials, such crucial insights might be missed entirely, allowing systemic inequities to persist unchallenged. Their involvement directly contributes to the identification of unique challenges and the development of tailored solutions.
• Building Trust and Reducing Health Inequities: Historical injustices, such as the Tuskegee Syphilis Study, have understandably fostered deep-seated mistrust within the Black community regarding medical research. Increasing the participation of Black researchers, clinicians, and community leaders in the design and execution of trials can help to rebuild this trust. When communities see themselves reflected in the research process, it fosters greater confidence and willingness to participate. This, in turn, helps to dismantle barriers to care and advance health equity.
• Developing Culturally Competent Care: Beyond the purely scientific aspects, diverse trial participation informs the development of culturally competent care. Understanding the social, economic, and cultural contexts that influence health behaviors and outcomes within the Black community is essential for designing effective interventions and support systems. This holistic understanding can only be achieved when research includes the voices and experiences of those it aims to serve.

Ultimately, this study on DANC serves as a powerful reminder of the hidden biases that can permeate cancer treatment and research. By actively addressing these biases and, critically, by ensuring robust and equitable representation of Black individuals in clinical trials, we can move closer to a future where everyone, regardless of their racial or ethnic background, has truly equal access to life-saving and effective cancer care.