Lenacapavir posts 100% HIV prevention in PURPOSE 1
Decision brief
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Gilead’s lenacapavir posted 100% efficacy in the Phase 3 PURPOSE 1 trial for HIV prevention in cisgender women. The result strengthens the case for Lenacapavir PrEP and raises the stakes for Gilead’s next regulatory and clinical catalysts.
Lenacapavir for HIV treatment already had a multidrug-resistant therapy niche; PURPOSE 1 then reset the prevention narrative. Twice-yearly injectable lenacapavir posted 100% HIV prevention efficacy in cisgender women, later anchoring FDA approval of Yeztugo for PrEP in adults and adolescents weighing at least 35 kg.
Contents10 sections
Key Takeaways
- PURPOSE 1: zero infections in the lenacapavir arm; 100% risk reduction versus background HIV incidence and superiority versus daily Truvada.
- NEJM publication (NCT04994509) confirmed 0 infections /100 person-years (95% CI 0.00–0.19) among lenacapavir recipients.
- FDA approved Yeztugo for PrEP on June 18, 2025, supported by PURPOSE 1 and PURPOSE 2.
- PURPOSE 2 reported two infections among 2,179 Yeztugo recipients (~99.9% remained HIV-negative) in a broader population.
What did PURPOSE 1 prove?
In the Phase 3 PURPOSE 1 trial, adolescent girls and young women in South Africa and Uganda were randomized to twice-yearly subcutaneous lenacapavir, daily oral F/TAF (Descovy), or daily oral F/TDF (Truvada). Lenacapavir produced zero incident HIV infections and was superior to both background HIV incidence and daily Truvada.
Full efficacy and safety results presented at AIDS 2024 reiterated zero infections (0/100 person-years) versus background incidence of 2.41/100 person-years, a 100% reduction, with statistical superiority versus Truvada (p<0.0001). Primary disclosure: Business Wire AIDS 2024 results.
How do peer-reviewed data frame the result?
The New England Journal of Medicine PURPOSE 1 paper reports 0 infections among lenacapavir recipients, 39 among F/TAF recipients, and 16 among F/TDF recipients in the analyzed cohorts, with low oral adherence and more injection-site reactions on lenacapavir (about 68.8% versus 34.9% on placebo injections). No new systemic safety concerns were identified in that report.
Where does FDA PrEP approval leave lenacapavir for HIV treatment?
On June 18, 2025, the FDA approved Yeztugo (lenacapavir) for PrEP to reduce sexually acquired HIV-1 risk in adults and adolescents ≥35 kg, requiring a negative HIV-1 test before initiation and with each injection. That prevention label is distinct from earlier treatment uses of lenacapavir in combination regimens for multidrug-resistant HIV-1.
Gilead’s approval wire notes PURPOSE 1 zero infections among 2,134 Yeztugo-group participants and PURPOSE 2’s two infections among 2,179 participants. See the June 2025 Business Wire approval release and FDA labeling on accessdata.fda.gov.
Strategic implications for PrEP markets
A twice-yearly injectable that beat daily oral Truvada on prevention efficacy changes the adherence and stigma calculus versus daily pills. Clinics can schedule two injection visits per year instead of relying on daily pill-taking, which may matter most where oral PrEP persistence is historically low. That operational shift still requires cold-chain or clinic capacity for subcutaneous dosing and reliable HIV testing before each injection.
Payers will demand HIV-negative confirmation workflows, resistance monitoring if infection occurs on PrEP, and net-price negotiations. Global access will hinge on voluntary licensing and procurement timelines rather than U.S. approval alone. For product strategists, Yeztugo’s PrEP launch also reframes how lenacapavir for HIV treatment is messaged: prevention and treatment audiences overlap in brand recognition but diverge in labeling, combinations, and safety communications.
Pipeline extensions beyond PURPOSE 1
PURPOSE 2 extended evidence to cisgender men and gender-diverse people, reporting two infections among 2,179 Yeztugo recipients and superiority versus daily Truvada and background incidence. Additional PURPOSE studies and once-yearly or oral long-acting concepts remain under evaluation. Registry context for PURPOSE 1 remains NCT04994509.
Those extensions do not change the core PURPOSE 1 fact pattern: zero infections on twice-yearly lenacapavir in the reported cisgender-women cohort. Competitive diligence should still compare injection-site reaction rates, oral lead-in requirements if any, and real-world continuation after the second and third doses—metrics that Phase 3 superiority on incidence alone cannot fully answer.
What remains unproven
PURPOSE 1 does not prove superiority to every future long-acting PrEP competitor, nor does it guarantee real-world effectiveness where injection visit adherence falters. Pricing, LMIC supply, and resistance outcomes after breakthrough infections need continued surveillance. Lenacapavir for HIV treatment outcomes in highly treatment-experienced patients remain a separate evidence base from PrEP and should not be inferred from prevention trial zeros.
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Frequently Asked Questions
What did PURPOSE 1 show for lenacapavir?
PURPOSE 1 found zero HIV infections among participants receiving twice-yearly subcutaneous lenacapavir, corresponding to 100% efficacy versus background HIV incidence and superiority versus daily oral Truvada (F/TDF) in cisgender women in sub-Saharan Africa.
Is lenacapavir FDA-approved for PrEP?
Yes. On June 18, 2025, the FDA approved Yeztugo (lenacapavir) as PrEP to reduce the risk of sexually acquired HIV-1 in adults and adolescents weighing at least 35 kg, based on PURPOSE 1 and PURPOSE 2.
How does PrEP use differ from lenacapavir for HIV treatment?
Lenacapavir for HIV treatment is a separate labeled use in combination antiretroviral regimens for multidrug-resistant HIV-1. PURPOSE 1 and the Yeztugo PrEP approval address prevention in people without HIV; treatment dosing, combinations, and resistance management follow different labeling.
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