Reaserching a Monthly Pill for PrEP for Cis Women

Researchers Receive $122 Million to Study Monthly Pill for PrEP

The University of Washington School of Medicine announced that it has received $122 million from the Bill & Melinda Gates Foundation to study the effectiveness of islatravir, a once-a-month pill for use as PrEP.

The five-year grant will support the IMPOWER 22 Phase 3 study, designed to evaluate the efficacy and safety of monthly oral islatravir as PrEP compared to a daily preventive pill. The study has begun screening and enrolling participants. The study will involve 4,500 healthy, HIV-negative cisgender women ages sixteen to forty-five, with 4,000 participants from across twenty-one African sites in South Africa, Uganda, Kenya, Malawi, Eswatini, Zimbabwe, and Zambia, and 500 women at sites in the southeastern and eastern United States.

The first women enrolled will be those aged eighteen or older. Once the safety of the once-a-month pill has been ascertained, the age will be lowered to sixteen to begin data collection from adolescent women. This is the first such study in which women who become pregnant during the trial will be given the option to remain on the regimen or to withdraw.

“This could be a game-changer,” Dr. Connie Celum, a UW professor of global health, medicine and epidemiology, and the study’s lead investigator, said in a press release. “The whole field is moving toward less adherence-dependent and easier strategies for users of HIV prevention.”

The UN’s global goal for 2020 was to have 3 million people on PrEP, but by year’s end, fewer than 1 million people worldwide had started taking the daily pills.

Celum’s research has shown that young African women, who account for twenty-five percent of new HIV transmissions worldwide, have grave doubts about using the daily-dosage PrEP available. They cite fear of being perceived as HIV-positive, challenges with discreet storage, potential side effects, and difficulty remembering to take the daily drug. “For some people, a daily pill is easy,” said Celum. “But when you’re talking about populations where sexual activity is stigmatized, particularly young African women, men who have sex with men, or female sex workers, there are a lot of barriers to taking a pill a day. If we’re going to impact the HIV epidemic through prevention, we have to do it at a much larger scale. If you only had to take one little tablet once per month and not deal with daily pill-taking and storage, that’s a totally different ball game.”

If the Phase 3 trial is successful, islatravir will be submitted to the U.S. Food and Drug Administration for review.

For details about UW Medicine, please visit

—Reporting by Hank Trout

Hank Trout, Senior Editor, edited Drummer, Malebox, and Folsom magazines in the early 1980s. A long-term survivor of HIV/AIDS (diagnosed in 1989), he is a forty-year resident of San Francisco, where he lives with his husband Rick.