In a new perspective piece published in the February 5 issue of Science, pharmacologist Namandje Bumpus, Ph.D. – who recently became the first African American to head a division at the Johns Hopkins University School of Medicine and the only African American to head a pharmacology division in the country – outlines the molecular origins for differences in how certain drugs work in different populations. It also puts forward a four-part plan to improve drug development equity.
“People are more similar than we are different,” says Bumpus. “However, the slightest change in our genetic material can cause huge differences in the way drugs work in our bodies. This is not a new idea.”
Genetic variants may be more common in some races than others, and as an advocate of diversity in science, Bumpus advocates that these differences make it even more important to increase diversity in clinical trials of new drugs and therapies. However, many clinical trials continue without differential involvement, potentially leading to poor results for people of color and less access to new therapies.
Some drugs available today, such as warfarin for blood thinning, have been shown to be less effective in people of African descent. According to previous studies, every fifth new drug approved by the FDA showed differences in effectiveness between ethnic groups.
Now that new treatments and vaccines are leading us to a critical turning point in a pandemic that disproportionately affects people of skin color, the need for better standards for diversity in clinical trials is greater than ever, says Bumpus, EK Marshall and Thomas H. Maren Professor and Director of the Department of Pharmacology and Molecular Sciences at the Johns Hopkins University School of Medicine.
However, simply increasing the number of underrepresented minorities in clinical trials is not enough to solve the systemic problems, she adds.
Bumpus’ framework for better drug development includes a four-part plan that includes laboratory research on cell and animal models to study genetic variability. better recruitment practices to diversify the academic workforce; Diversity requirements for funding agencies; and requirements for diversity reporting on clinical trial demographics in articles published in scientific journals.
By implementing diversity requirements that require diversity among clinical trial participants and in trial design, funding agencies would ensure accountability – and scientific journals would increase transparency to their audiences, Bumpus says. At the research, biotech and pharmaceutical company level, Bumpus advocates hiring practices to build a more diverse workforce. With a diverse workforce comes a diversity of thoughts, and an increased likelihood that researchers will be better prepared to incorporate genetic variation into their studies.
She notes that animal models can be genetically engineered to reflect differences between ethnic groups, possibly to “improve the predictability of drug outcomes and provide a mechanistic basis for understanding disparities”.
Genetic variations associated with drug response are often linked to a family of enzymes important in drug metabolism known as cytochrome P450. This family of enzymes in humans processes about 75% of the drugs available clinically.
Still, subtle genetic differences can alter the enzyme in humans, and some gene variants are more common in certain ethnic groups. The altered enzyme could affect how drugs are processed and used by the body, so what works for one person may be ineffective or toxic to another.
Since most clinical trials of these drugs included people of European descent and a small number of people of African descent, differences in drug efficacy are often not immediately known.
Bumpus said the framework could force the drug development field to take steps toward a future where “treatments are most likely to work for all people” and “do not exacerbate existing health disparities.”
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