While representing just over half of people living with HIV worldwide, women are still largely absent from clinical trials. This could jeopardize the chances of finding a remedy that is as effective for them as for men.
Today, women make up more than half (54%) of the 35 million HIV-positive people in the world. In France, the number of women living with HIV is estimated at 40,000. A third of new HIV infections discovered each year concern women, the majority of whom come from sub-Saharan Africa, South America or the southern -United.
But, a sign that gender inequalities still persist in the field of medical research, women are still largely excluded from clinical trials for potential treatments, vaccines or cures for the AIDS virus. This astonishing paradox is brought to light in an article by New York Times published this week: how to fight against a pandemic disease without taking into consideration the specificity of half of the people carrying its virus?
Two specific immune systems
According to the American daily, researchers are now more aware of this bias in their trials, which however continue to depend heavily on the participation of gay volunteers. Taking this problem into account is all the more important since women and men often react differently to HIV infection because their immune systems differ.
“There are all kinds of differences between men and women, probably partly due to hormonal effects,” explains the New York Times Dr. Monica Gandhi, professor of medicine at the University of California, San Francisco. Thus, the female hormone estrogen seems to “put to sleep” the virus in the organism. However, a dormant virus is more difficult to eliminate, either by the immune system than by drug treatment.
Different reactions to treatments
In 2016, a study conducted by amfAR (American Foundation for AIDS Research), one of the largest American foundations in the world for the financing of prevention and medical research against AIDS, showed that women represented a median of 11% in cure trials. They are only 19% to participate in trials on antiretroviral drugs and 38% in studies on vaccines.
“If we’re going to find a cure, it’s important that we find a cure that really works for everyone,” said Rowena Johnston, director of research at amfAR.
This gendered difference in access to clinical trials is all the more damaging since women and men do not react in the same way to HIV treatments either. For example, a systemic antiviral called dolutegravir may increase the risk of neural tube defects in children born to mothers who take this drug. The antiretroviral drug nevirapine is more likely to cause a severe rash in women than in men. However, it has been tested on 85% of men.
This absence of diversity in clinical trials is all the more flagrant when we are only interested in black women. For Ublanca Adams, a 60-year-old Californian with HIV, this added barrier for women of color is largely down to mistrust due to a “long history of exploitation by medical researchers.” “There is still a lot of stigma in our research author community,” she explains, lamenting information around the different treatments that is “neither inclusive nor inviting”.
A slow evolution
But why are clinical trials primarily based on predominantly male cohorts? Because it is an “easy way out”, believes the New York Times. Indeed, studies involving female subjects are subject to greater scrutiny by the Food and Drug Administration (FDA) because the American health agency applies very strict rules to include women of childbearing age.
The researchers therefore prefer to recruit men and settle for collecting data from women once the drug has received its marketing authorization.
Fortunately, things are slowly changing. Two recent trials of long-acting antiretroviral drugs – which can be injected monthly instead of taken by mouth daily – have been successful in attracting significant numbers of women: 33% of participants in one study and 23% to the other.
Another trial, meanwhile, focuses only on women, and is looking at a drug that blocks estrogen to see if it facilitates the elimination of HIV. Its authors, however, had to make some concessions and recruited postmenopausal women to circumvent FDA restrictions. However, these participants have lower levels of estrogen, which can skew the results. Yet the lead author is optimistic. “We were one of the fastest trials to recruit. Women are ready to participate,” said Dr. Eileen Scully, assistant professor of medicine at Johns Hopkins University.
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