Event-driven PrEP for women may work, modelling study predicts
Injectable PrEP clearly works at least as well for cisgender women having vaginal sex as it does for people having anal sex. But there remains some uncertainty as to whether the much lower effectiveness of oral PrEP seen in most studies in women is entirely due to poorer adherence, or whether biological differences in drug absorption and elimination also contribute.
These doubts continue to affect dosing recommendations for women using PrEP and have prevented event-driven or ‘on demand’ PrEP for women from being adopted in guidelines. One 2017 paper concluded that event-driven PrEP could not work for women.
However, a modelling study presented by Dr Mackenzie Cottrell of the University of North Carolina at last week’s Conference on Retroviruses and Opportunistic Infections (CROI 2025), has found that, based on studies of drug absorption and clearance, event-based dosing for women using tenofovir disoproxil/emtricitabine (TDF/FTC) should be effective. The model related drug levels in tissues in women to observed efficacy cells taken from the female genital tract, circulating lymphocytes and rectal tissue.
Read the full news story at aidsmap.
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HIV acquisition in women with good adherence to TAF/FTC PrEP is rare
Evidence for the effectiveness of the alternative formulation of oral PrEP in women was presented at the Conference on Retroviruses and Opportunistic Infections (CROI 2025) in San Francisco last week.
The data come from the PURPOSE 1 study, conducted with 5338 cisgender women in South Africa and Uganda. The study compared HIV prevention efficacy of injectable lenacapavir and two types of oral PrEP: the oldest, cheapest and still most-used option of tenofovir disoproxil and emtricitabine (TDF/FTC), and the alternative formulation, tenofovir alafenamide and emtricitabine (TAF/FTC). As no studies have previously tested TAF/FTC in cisgender women, drug regulators have not approved the formulation for this population.
Read the full news story at aidsmap.
View all aidsmap reports from CROI 2025
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