NATIONAL HARBOR, MD. -- Over 25 years of clinical research, phase 3 trials of approved disease-modifying therapies (DMTs) for multiple sclerosis (MS) were overwhelmingly made up of White subjects, a new analysis finds, and many studies failed to report percentages of non-White subjects at all. Researchers also found that the websites of multiple major drug manufacturers don’t include any trial data about how medications may affect people of different races and ethnicities.
It’s clear that “non-White participants are significantly underreported and unrepresented,” said study corresponding author and Dell Medical School/The University of Texas at Austin neurologist Leorah Freeman, MD, PhD, in an interview.
The study was presented at the annual meeting of the Consortium of Multiple Sclerosis Centers and published in Neurology.
“The lack of diversity in MS research is something that has been sporadically discussed in the past. By conducting this systematic review of MS phase 3 trials, we wanted to put numbers on this issue and review the evidence systematically,” Dr. Freeman said. “By doing so, we hoped to raise awareness about the problem of underreporting and underrepresentation of non-White participants in trials so that we, as a community involved in MS research, can start having the difficult conversations needed for change to occur.”
25 years of clinical research
The researchers reviewed 44 phase 3 studies from 1995-2020 that represented 45 trials. “We wanted to capture data from the very first global trials being conducted for the approval of MS DMTs, and the first was published in 1995,” Dr. Freeman said. “We were interested in understanding the impact of trial globalization over a long period of time on diversity of enrollment.”
The studies include trials of mainstays of MS treatment such as interferon, glatiramer acetate, teriflunomide, dimethyl fumarate, diroximel fumarate, fingolimod, natalizumab, and others.
The researchers found that 17 (37.8%) of the trials did not report race or ethnicity, 14 (31.1%) reported race and ethnicity as proportion of White participants only, and 14 (31.1%) reported 2 or more races/ethnicities.
Of the 28 trials with racial breakdowns, the median percentage of White participants was 93.8% (range 78.5-99.6% across 28 studies), 1.9% for Black participants (range 0.1-8.1% across 14 studies), and 0.5% for Asian participants (range 0.1-14.5% across 11 studies).
The studies often failed to account for non-White subjects even though “Black people, in particular, have been shown to have a more severe disease course,” Dr. Freeman said.
A 2022 study of more than 2.6 million Southern California adults finds that prevalence of MS was similar among White and Black people at about 230 per 100,000. “Taken together with previous studies, these findings indicate that the burden of MS in the United States Black community has long been underrecognized,” the researchers wrote.
According to Dr. Freeman, it’s unclear why the studies were so dominated by White subjects. “Lack of awareness about the importance of this information likely explains why this information often goes unreported.”
She highlighted the TOWER (teriflunomide) and DEFINE and CONFIRM (dimethyl fumarate) studies as positive examples. “We noted the inclusion of trial sites in Asia and consequently a higher representation of Asian people with MS in those trials. We felt these studies were examples of how trial globalization can support better representation of underrepresented groups.”
And she noted that the ongoing CHIMES trial is examining the use of ocrelizumab in Black and Hispanic people with MS. “This study was designed in partnership with MS patients and advocacy groups to bridge gaps in clinical trial participation in these communities,” she said. “Innovative strategies were developed to increase participation of Black and Hispanic patients in this trial.”
What should happen next?
Going forward, Dr. Freeman said, “MS researchers, DMT manufacturers, sponsors, and publishers need to set better standards for racial and ethnic representation and reporting in trial publications.”
In an interview, epidemiologist Luisa N. Borrell, DDS, PhD, a professor who studies race and medicine at City University of New York, said the new study is valid and useful. She noted that it reflects the findings of a 2022 analysis of more than 20,500 clinical trials in the U.S. from 2000-2020: Only 43% reported racial/ethnic breakdowns, and the subjects were much more White than the population at large.
Possible reasons for the disparity include distrust among possible participants and lack of health literacy, she said, which are both “modifiable issues.”
Dr. Borrell added: “Clinical trials should aim to recruit populations affected by the outcome of interest. That would allow for the intervention to effectively treat those who need it the most. Moreover, the lack of diversity of trials brings issues of generalizability and transportability of the findings.”
No funding is reported. Dr. Freeman and some of the other study authors report various disclosures.