The cost of racial disparities in clinical trials
Black Americans are consistently underrepresented in clinical trials for diseases ranging from diabetes to heart disease to different cancers, despite being disproportionately affected by many of them.
Why it matters: The current COVID-19 pandemic is taking an unequal toll on underrepresented communities. As researchers race to develop treatments, having diverse trial participants is key to creating safe and effective drugs and to understanding how socioeconomic and environmental factors influence diagnosis, treatment and outcome.
Case in point: This week, a steroid was hailed as a "breakthrough" treatment and the first to save lives of some people with COVID-19. The preliminary results from the University of Oxford found dexamethasone reduced deaths by one-third in ventilated patients.
- Yes, but: There also is some evidence that African Americans may respond differently to glucocorticoids like dexamethasone, such as having a diminished response, says Namandjé Bumpus, professor and chair of the pharmacology department at Johns Hopkins University School of Medicine.
- "[W]e need to make sure that [with] all of this excitement about dexamethasone ... black people are included" in any study on its impact, she adds.
- The study authors did not respond to requests for information about the racial and ethnic makeup of the 2,104 randomized patients in the study, which has not been peer reviewed or distributed as a preprint.
- Meanwhile, the University of Pittsburgh Medical Center says its separate trial testing multiple COVID-19 treatments (including corticosteroids similar to dexamethasone) has about 50% African American patients and roughly 50% female participants enrolled so far.
Other examples: A new class of anti-cholesterol drugs, called PCSK9 inhibitors, was found after working with a small population of African Americans with genetic variants linked to super-low cholesterol levels, says Josh Denny, CEO of the National Institutes of Health's All of Us program, an effort to build one of the most diverse health databases.
- He also points to the finding that the blood-thinning drug Clopidogrel does not work in most Pacific Islanders (which led to a lawsuit and a countersuit) and that it appears African Americans often need more immunosuppressants when they've had a kidney transplant.
The big picture: African Americans, Latinos, women and older people tend to be particularly underrepresented in clinical trials, Bumpus says.
- More than 80% of genome-wide association studies are based on people of European descent, an analysis found.
- Most human and animal studies have been done in males, so different effects experienced by women are often not taken into account, Bumpus points out. For example, only 34% of participants in trials for cardiovascular drugs were female even though cardiovascular diseases are the leading cause of death for women.
- 36% of people in trials of new drugs approved in 2019 were over the age of 65.
- Poor representation in trials "could result in the use of new drugs that have little data about the efficacy of the new treatment or its side effects in that population," says Joseph Unger, who studies disparities in clinical trials and barriers to participation at the Fred Hutchinson Cancer Research Center. "Ultimately, it can impact how treatments are disseminated into vulnerable populations."
Zoom in: From studies of prostate cancer treatments, prevention and screening to those of new heart disease and cancer drugs, African Americans have long been underrepresented in clinical trials — including those for diseases that disproportionately impact their communities.
- Distrust in the medical system is a big factor because of historical events. For example, the federal government's Tuskegee Study intentionally did not provide penicillin treatment to black men with syphilis so researchers could study the disease.
- A lack of transportation and child care along with work constraints also play a role, as does having other health conditions that can exclude people from trials.
- There's also less awareness of clinical trials, whether because providers are less likely to discuss possible trials with black patients compared to white patients or hospitals that predominantly serve people of color have fewer open trials than others.
What to watch: This week, All of Us announced steps it's taking to better study how COVID-19 affects underrepresented communities.
- AI is playing an increased role in vaccine trials and decisions about telehealth in the pandemic but "providers need to watch which groups are likely to be underrepresented in the data used to train algorithms, along with patterns of inequality in existing health systems," Axios' Ina Fried points out.
- As telehealth is quickly adopted in the pandemic, it may be that researchers and institutions will look to make some aspects of clinical trials remote, possibly increasing diversity in them in the process, says Harvard Medical School's Emily Rencsok, a graduate student and author of the study about prostate cancer trials.