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Of the estimated 38 million people living with HIV around the world, more than half are women. Women, especially young women, are at greater risk for HIV infection than men.

So why would a company omit cisgender women from its clinical trials testing a pre-exposure prophylaxis (PrEP) regimen?


PrEP is a breakthrough HIV strategy that, when taken as a daily pill, is more than 90% effective at preventing sexually acquired HIV. The first drug for PrEP, Truvada, has become an essential tool for bringing us closer to ending the HIV epidemic in the U.S. and around the world.

Gilead Sciences, which manufactures Truvada, sought Food and Drug Administration approval to market Descovy, its anti-HIV therapy, as a PrEP regimen. According to the company, it would have required too many resources to enroll a sufficient number of cisgender women into a trial and closely monitor their adherence to the daily pill regimen. The company presented the FDA with data only from a clinical trial involving men who have sex with men, and transgender women.

So when the FDA approved Descovy for PrEP last month, it did not approve it for those “at risk from receptive vaginal sex,” but only for men who have sex with men and transgender women. Member of the FDA advisory committee, however, had cited significant concerns that cisgender women were not included in studies presented for the drug’s licensing.


Gilead’s approach is incredibly disappointing. I have spent nearly 10 years working in HIV research and now lead the New York City Health Department’s Bureau of HIV, in addition to being a primary care physician and HIV specialist. I have seen firsthand the effect of HIV on women, as well as the lack of funding and institutional support for research on women.

The fact that women are more likely to acquire HIV stems from a confluence of factors, including structural forces that disproportionately impact women, from poverty and lack of education to sexual and gender-based violence and restrictive laws that limit women’s ability to protect their sexual and reproductive health. Yet even though they bear a significant burden of the HIV/AIDS epidemic, women still do not have equitable access to HIV prevention and treatment, nor equitable opportunities to participate in HIV research.

Given Gilead’s earnings and past spending on HIV drug research and development, the company is more than capable of addressing the “challenges” of including cisgender women in PrEP clinical trials. Rather than exclude cisgender women from participating in the Descovy trials, Gilead could have and should have invested in formative work and community engagement to ensure successful recruitment of this important group for HIV prevention.

The use of PrEP among men who have sex with men in the U.S. has skyrocketed by approximately 500% since 2014, while its use among cisgender women has essentially flatlined. As men who have sex with men currently constitute the majority of the market share for PrEP in the U.S., Gilead’s decision to exclude cisgender women from its clinical trials for Descovy appears nothing short of profit-driven.

The lack of cisgender women in clinical trials of HIV drugs and the FDA’s willingness to tolerate studies that do not include them are indicative of a broader and more systemic disregard for women’s health.

Sadly, this is nothing new. There’s a dearth of data on the safety and efficacy of PrEP in women relative to men, and even fewer data on interventions that could help them more readily use it and stick with it. This has translated into misconceptions among many women and their providers about whether women are candidates for PrEP and can take PrEP safely.

We have reached a juncture when the end to the domestic HIV epidemic is in sight. But we cannot move forward if we leave women behind.

Oni Blackstock, M.D., is the assistant commissioner for the Bureau of HIV at the New York City Health Department.

  • I think women should be included in such trials, especially something as widespread as HIV. It is not just a “male” disease.
    And as a women I reject the term “cis”. It is outrageous that men and “transwomen” aka men are completely disregarding women’s health.

  • Note to the author…Dr. Blackstock, thank you for your critique of both the FDA and Gilead Science regarding the exclusion of women from clinical trials of the anti-HIV drug Descovy. The critique is entirely justified, however, there are multiple problems with your use of terminology. You wrote that Gilead Sciences excluded “cisgender women” and presented the FDA with data only from a clinical trial involving “men who have sex with men, and transgender women”. If you are intent on being consistently politically correct, and you have called genetic females “cisgender women”, you must also call genetic males “cisgender men”. Moreover, the correct term for genetic males who have transitioned to female is “transwomen”.

    Frankly, in service of absolute clarity on matters of life and death, such as prevention of HIV/AIDS, it would be best to dispense with the politically correct terminology altogether and just spell out the facts in the most biologically correct terms possible.

    • “Females” seems to me the simplest and most precise term. “Cisgender women” is just saying “females, and ooh look at me, I know the fashions and I’m better than you!”

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