Lenacapavir is a long-acting HIV capsid inhibitor that has demonstrated high effectiveness in preventing HIV acquisition when used as PrEP. Unlike oral PrEP, which requires consistent daily medication, lenacapavir is administered via a subcutaneous injection every six months.
The significance of this innovation was demonstrated in the PURPOSE 1 clinical trial, which investigated HIV prevention among adolescent girls and young women in South Africa and Uganda. The trial reported zero HIV infections among participants receiving twice-yearly lenacapavir during the primary analysis period, demonstrating 100% efficacy against HIV acquisition in the trial population (Bekker et al., 2024).
Similarly, the PURPOSE 2 trial demonstrated approximately 96% efficacy compared with estimated background HIV incidence among a diverse population of cisgender men and gender-diverse individuals (Kelley et al., 2025).
These findings represent an important milestone in HIV prevention science. They suggest that long-acting prevention technologies could address some of the structural and behavioural challenges associated with daily oral PrEP.
In June 2025, the World Health Organization (WHO) issued recommendations supporting twice-yearly injectable lenacapavir as an additional HIV prevention option, recognising its potential to expand choice and improve access to HIV prevention services (WHO, 2025).
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