PrEP4U: Assessing the Effectiveness of Integrated Same-Day Lenacapavir Initiation and Follow-up Choice on PrEP Persistence

Since the introduction of oral PrEP over a decade ago, more than 1.3 million HIV infections occur globally each year, far exceeding the UNAIDS 2030 target of < 335,000 cases. UNAIDS estimated that only 2.3 million people used PrEP in 2023, far below the target of 10 million by 2025. Oral PrEP persistence remains low, with many individuals discontinuing within 6-12 months. Factors contributing to low uptake and persistence include pill fatigue, stigma, access barriers, and medical mistrust. The gap is especially stark in sub-Saharan Africa and Latin America, where PrEP coverage lags behind epidemic burden.

The United States mirrors this global picture; despite broad access to healthcare, disparities in uptake and continuation persist along racial, ethnic, and gender lines. According to the CDC, in 2022 only 36% of individuals eligible for PrEP were prescribed it. Marked disparities exist: Black and Hispanic/Latino individuals and women represent a disproportionate share of new HIV diagnoses but a much smaller fraction of PrEP users. In Massachusetts, for example, Black and Hispanic/Latino individuals accounted for 35% and 31% of new HIV cases in 2022, yet only 7% and 12% of PrEP users in 2023, respectively. These disparities highlight ongoing barriers to access, stigma, and persistence.

Lenacapavir is a first-in-class HIV-1 capsid inhibitor with a novel mechanism of action and an exceptionally long half-life, enabling subcutaneous administration every 26 weeks. PURPOSE 1 and PURPOSE 2, large multicenter randomized clinical trials, established lenacapavir's efficacy for HIV prevention. In PURPOSE 2, a Phase 3 randomized trial of over 3,000 participants at risk for HIV infection, HIV incidence with lenacapavir was 0.10 per 100 person-years, compared to 0.93 per 100 person-years in the oral F/TDF arm and 2.37 per 100 person-years in the background incidence cohort. Lenacapavir reduced HIV incidence by 96% compared with background incidence and by 89% compared with oral PrEP. No major safety concerns were identified, though 1.2% discontinued due to injection-site reactions. These findings, published in the New England Journal of Medicine in 2025, demonstrated that twice-yearly lenacapavir is a highly effective PrEP agent.

Lenacapavir addresses key limitations of oral PrEP:

• Persistence challenges with daily oral adherence.
• Barriers to clinic attendance for frequent refills or injections.
• Stigma associated with oral PrEP use, which may be mitigated by less frequent, more discreet dosing.

Thus, lenacapavir has the potential to transform HIV prevention - if delivery strategies are optimized.

While clinical trials demonstrate efficacy, implementation science questions remain:

1. Same-day initiation: Oral PrEP initiation has successfully shifted to same-day models. However, injectable PrEP initiation has been complicated by requirements for multiple laboratory tests, delaying access. PURPOSE 1 and 2 used a combination of rapid HIV Ag/Ab, laboratory Ag/Ab, and quantitative RNA tests prior to injection. In real-world settings, RNA testing may be impractical and introduce delays. Rapid HIV testing, with confirmatory laboratory Ag/Ab tests pending, is a feasible approach aligned with WHO guidance. This balance enables timely initiation without undue barriers.
2. Follow-up and persistence: Lenacapavir's twice-yearly dosing reduces pill burden but raises questions of where and how injections are delivered. Relying on centralized hospital clinics may perpetuate barriers (transportation, stigma, scheduling). In contrast, home-based and community-based PrEP delivery have shown promise for improving persistence and acceptability.

Suffolk County, Massachusetts - home to central Boston - is designated a high-burden HIV area in the U.S. "Ending the HIV Epidemic" initiative, reporting 118 new HIV diagnoses in 2022. Despite broad health insurance coverage and a state-sponsored PrEP assistance program, PrEP uptake and persistence remain insufficient among Black, Hispanic/Latino, and female populations. PrEP4U will specifically recruit participants from these priority populations through community partner organizations, mobile van services, and clinical sites. The trial is designed to address equity gaps by testing models of care that reduce stigma, bring services closer to people, and incorporate patient choice.