Gilead's PURPOSE 1 extension shows zero new HIV cases through 52 weeks
Long-term follow-up data heading to AIDS 2026 extend lenacapavir's PrEP efficacy signal, though the presentation covers a contraceptive sub-analysis rather than fresh incidence results.
Executive Summary
- Gilead will present extended open-label follow-up from its Phase 3 PURPOSE 1 prevention trial at a July HIV conference, adding a year of real-world use on top of the data that already won lenacapavir its US approval.
- No new infections turned up among participants who stayed on or switched to twice-yearly lenacapavir, and injection adherence held up through the full follow-up period, extending rather than revising the drug's approved efficacy record.
- Lenacapavir remains the only capsid inhibitor in Phase 3 testing for HIV prevention, with its nearest mechanism neighbors being Gilead's own integrase and reverse-transcriptase franchises rather than a rival capsid program.
- Gilead is using the moment to talk up regulatory filings and no-profit supply expansion beyond the US, a signal about reach and access rather than a change to the clinical case itself.
The presentation
Gilead Sciences, Inc. said it will present new long-term follow-up data from the open-label extension phase of PURPOSE 1 (NCT04994509) at the 26th International AIDS Conference, running July 26-31 in Rio de Janeiro. PURPOSE 1 is the Phase 3 trial that tested twice-yearly lenacapavir injections against daily oral PrEP in adolescent girls and young women across South Africa and Uganda, enrolling 5,368 participants. The trial's randomized blinded phase already met its efficacy endpoints and was unblinded early in June 2024; this presentation covers what happened next, as participants moved into an extension phase and continued on the drug. Gilead+1Gilead to Present New HIV Research at AIDS 2026 Across Prevention, Treatment and CureJul 21, 2026Pre-Exposure Prophylaxis Study of Lenacapavir and Emtricitabine/Tenofovir Alafenamide in Adolescent Girls and Young Women at Risk of HIV InfectionNCT04994509
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
The result
More than 95% of eligible PURPOSE 1 and PURPOSE 2 participants chose to continue on lenacapavir or switch to it from daily oral PrEP after the blinded phase ended. In PURPOSE 1, Gilead said no new HIV infections were observed during the extension phase, including among those who switched over from daily pills, across more than 7,178 person-years of follow-up. Adherence, defined as receiving injections on the twice-yearly schedule, held at 96% through 52 weeks. The safety profile stayed consistent with the randomized phase, with no new safety signals and no difference in signals between those who stayed on lenacapavir and those who switched to it. GileadGilead to Present New HIV Research at AIDS 2026 Across Prevention, Treatment and CureJul 21, 2026
What the label already established
Lenacapavir is approved in the US as Yeztugo for HIV pre-exposure prophylaxis, an approval the FDA granted in June 2025 built on the PURPOSE 1 and PURPOSE 2 program. A separate lenacapavir formulation, Sunlenca, is approved for treatment of multidrug-resistant HIV. Because the prevention indication is already approved, this extension data functions as a durability update on an established efficacy and adherence profile rather than a new pivotal test. The trial's own protocol history shows the primary completion date moved three times between 2023 and 2025, most recently settling at May 27, 2024 after the trial had already reported results, a pattern typical of a trial finalizing its record after an early unblinding rather than a sign of instability going forward. NCT04994509Pre-Exposure Prophylaxis Study of Lenacapavir and Emtricitabine/Tenofovir Alafenamide in Adolescent Girls and Young Women at Risk of HIV InfectionNCT04994509
Where lenacapavir sits in the field
Lenacapavir is the only capsid inhibitor in Phase 3 testing for HIV infection prevention; the trial data show no other capsid-targeted program has reached that phase in this indication. Its closest comparators by mechanism are Gilead's own bictegravir, an integrase inhibitor tested in combination regimens, and islatravir, a reverse-transcriptase-targeted nucleoside analog, both different targets within the same small-molecule modality. Beyond Gilead's own portfolio, ViiV Healthcare's cabotegravir and dolutegravir represent the established long-acting and daily oral integrase-inhibitor competition in HIV-1 infection. None of these share lenacapavir's capsid mechanism, leaving twice-yearly dosing as the axis lenacapavir competes on against daily oral and injectable alternatives that require more frequent administration.
The regulatory framing
Gilead's release describes advancing regulatory filings across additional regions and engaging the Pan American Health Organization to explore access pathways in Latin America, alongside plans for generic availability and an expanded no-profit supply commitment. Those statements point to geographic reach and access rather than a new clinical hurdle, since the US approval for prevention is already in place. GileadGilead to Present New HIV Research at AIDS 2026 Across Prevention, Treatment and CureJul 21, 2026
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.