“Racial diversity in clinical trials serves as a metric of societal equality and access to health care,” Dr. Kanwal Raghav of The University of Texas MD Anderson Cancer Center, in Houston, and colleagues write in JAMA Oncology, online August 15. It also allows “assessment of biologic differences that may determine differential efficacy of drugs,” they add.
Dr. Raghav added in an email to Reuters Health, “Representation of select racial groups in cancer clinical trials (even pivotal clinical trials) has been deficient over the years indicating a concerning persistence of healthcare inequity, conceivably a result of complex socioeconomic dynamics.”
The researchers examined data from 230 trials involving more than 112,000 participants. These supported FDA oncology-drug approvals granted between 2008 and 2018.
Only 13 Native Americans reportedly participated in these trials and analyses were restricted to four major race/ethnicity categories within the United States: white, Asian, black and Hispanic.
Sixty-three percent of the studies reported on at least one race, while the rest had no mention of race. Only 18 (7.8%) documented the four categories and 58 (25.2%) reported race subgroup analyses.
Reporting on whites was included in 144 trials (62.6%). For Asians, the number was 47.8%, for blacks 38.2% and for Hispanics 10.0%. Race reporting in trials changed “minimally” over the study period, from 55.6% in 2008-2013 to 67.1% 2013-2018.
Black and Hispanic patients, the researchers add, “were consistently underrepresented compared with their expected proportion based on cancer incidence and mortality in the United States, whereas Asian patients appeared to be overrepresented, and white patients had enrollment that nearly matched their expected proportion.”
“Compared with whites (98% of expected proportion), blacks (22% of expected proportion) and Hispanics (44% of expected proportion) were underrepresented in these trials relative to their proportion among the US cancer population,” the team reports.
Dr. Otis W. Brawley, professor of oncology and epidemiology at Johns Hopkins University, in Baltimore, Maryland, and former Chief Medical and Scientific Officer of the American Cancer Society, questioned the basis of the study.
“While I encourage diversity and inclusion of as many people as possible in clinical research,” he told Reuters Health by email, “this paper makes a mistake that many in science and society are making. The NIH Revitalization Act of 1993 is legislation that requires we use race as a biological construct. This paper and the law assume that race is a biological categorization. The focus is on racial diversity, we need to focus on knowing how a drug is metabolized and how that varies among populations identified by genetics. Racial diversity does not ensure the validity of research, nor does it assure equity in health.”
“In reality,” Dr. Brawley said, “race is a sociopolitical categorization. Indeed, the one thing that (genetic-testing companies) 23andMe and Ancestry.Com have shown us is that these racial categories are not suitable for biologic categorization. Blacks in the U.S. have lots of European, African and native American genetics in varied amounts. There is high variability within so-called Blacks as to how they metabolize any drug.”
“Categorizing populations by race is like slicing soup, it just does not work,” he concluded.
JAMA Oncol 2019.