No More Excuses: Vaccine Trials Prove Clinical Trial Diversity Is Doable

John Whyte, MD, MPH


February 10, 2021

The increased representation of minority patients in the COVID vaccine trials puts the rest of medicine to shame.

John Whyte, MD, MPH

For decades there have been calls to make clinical trials more diverse, but the 2015-2019 Drug Trials Snapshots Summary Report by the US Food and Drug Administration (FDA) shows that the efforts to date haven't made much difference.

At first glance, there seem to be a few points to celebrate in the report, especially when it comes to women. Slightly more than half of all clinical trial participants during the past 5 years were women. That's huge progress from a few years before, when it was often less than 30%. However, minority participation is disappointing. Only 7% of participants were Black and/or African American, and 13% were Hispanic.

US vs Eastern Europe

When you stratify by location of sites, 16% of clinical trial enrollees in the United States were Black. Keep in mind that more than 65% of clinical trials are conducted outside the United States, largely in Eastern Europe. Countries such as Poland and Russia have set up clinical trial enterprises that funnel patients to a few centers to facilitate efficient recruitment, but participants in these countries typically do not match the diversity of the United States.

If you scrutinize the final pages of the report, you will see what I mean in the tables and graphs that stratify therapeutic areas by sex, age, race, and ethnicity. For cardiovascular disease trials, only 3% of all male participants under age 65 were Black compared with 79% White. The case is not much better for Black women, who represent 6% of female participants below age 65 and a paltry 2% aged 65 or older.

Diabetes is a leading cause of death in minority populations, but only 5%-7% of participants under age 65 in endocrinology trials were Black. American Indians represent less than 1%. How is it that for a condition that affects literally millions of brown and Black persons, shockingly few such persons are enrolled in trials of that condition?

Representation in oncology trials is also concerning. If you have a cancer that is not responsive to standard therapy, you don't have many options unless you enroll in a clinical trial. Yet, Black men and women comprise less than 5% of participants in cancer clinical trials, and Hispanic men and women less than 8%. Keep in mind that major cancer centers sit in geographically diverse locations such as Boston, Atlanta, and Philadelphia. Who's coming in their doors to enroll? We know it's not people of color.

Stigma and Race

If you are looking for proportionality, look no further than infectious diseases, where Black persons typically represent 20% of participants. Isn't it odd that infectious disease investigators can enroll a large percentage of minorities in their trials, but diabetes, heart disease, and cancer researchers can't?

What may be most striking is clinical trial participation for conditions that have stigma. Schizophrenia and bipolar disorder are roughly equally prevalent in Black and White Americans. In 2015, five mental health drugs were approved — three for schizophrenia, and one each for bipolar disorder and depression. In the schizophrenia trials, Black participation ranged from 24% to 40%; for bipolar disorder it was 25%. Yet for depression, it was only 12%.

Of note, the same drug was used in the depression and schizophrenia trials. So why was Black enrollment double for one disease compared with the other? Same drug, same trial sites. Is it a success story that the schizophrenia trial had so many Black participants or is it an example of systemic bias that more people of color are enrolled in trials of diseases that have stigma?

COVID might be the catalyst for finally increasing diversity in research trials. Both the Pfizer and Moderna vaccine trials had close to 40% minority participation. How did they do it? It started with a commitment upfront, before recruitment began, given the disproportionate impact that COVID has had on communities of color. Other trials need to do the same.

Let's stop talking about increasing the number of clinical trial sites. We've been talking about it for years with little, if any, change in who participates.

Instead, we must have a public commitment to diversity in clinical trials. We should not wait until a drug is approved and marketed to determine whether there is variability of response by sex, age, race, or ethnicity. We need to revise clinical trial inclusion criteria which often are unnecessarily restrictive. And let's reimburse patients for routine costs of clinical trial participation; these are not unethical inducements.

Longer-term, we need to have more Black and Hispanic researchers and clinical trial recruiters. The clinical and scientific communities have demonstrated through vaccine studies that diversity in clinical trials is possible. We now need to make it happen.

John Whyte, MD, MPH, is a board-certified practicing physician and chief medical officer at WebMD. He formerly worked at the Center for Drug Evaluation and Research at the US Food and Drug Administration, where he developed numerous initiatives to address diversity in clinical trials, including the drug trials snapshot program.

You can follow him on Twitter @DrJohnWhyte

Follow Medscape on Facebook, Twitter, Instagram, and YouTube


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.