Gilead Sciences, Inc. (GILD Quick QuoteGILD - Free Report) recently announced additional efficacy, safety and demographic data from its late-stage study on lenacapavir, a twice-yearly injectable HIV-1 capsid inhibitor, for the prevention of HIV.

Data reinforce that twice-yearly lenacapavir could be a highly effective and potentially game-changing HIV prevention option.

Additional Data From GILD’s HIV Study

The double-blind, multicenter, randomized study phase III study, PURPOSE 2, is evaluating the safety and efficacy of twice-yearly subcutaneous lenacapavir for pre-exposure prophylaxis (PrEP) versus once-daily oral Truvada and background HIV incidence (bHIV) in 3,273 cisgender gay, bisexual, and other men, transgender women, transgender men, and gender nonbinary individuals aged 16 years or older.

Safety and tolerability findings from PURPOSE 2 demonstrated no significant or new safety concerns. Lenacapavir was generally well-tolerated.

Last month, Gilead announced that lenacapavir was highly effective at reducing infections among trial participants. 99.9% of participants did not acquire HIV in the lenacapavir group, with two incident cases among 2,179 participants.

The results demonstrated the superiority of twice-yearly lenacapavir over bHIV with 96% relative risk reduction compared with nine incident cases among 1,086 individuals in the Truvada group. Additionally, twice-yearly lenacapavir was 89% more effective than once-daily Truvada.

There were fewer discontinuations due to injection site reactions with lenacapavir.

Per Gilead, PURPOSE 2 is the second late-stage study to demonstrate superior efficacy for twice-yearly lenacapavir for the investigational use of HIV prevention as PrEP. The study is was unblinded early because it met its key efficacy endpoints.

In June 2024, Gilead reported that the PURPOSE 1 trial evaluated lenacapavir for PrEP among cisgender women in sub-Saharan Africa. The trial was also unblinded early because it met its key efficacy endpoints.

Per Gilead, the importance of studying HIV prevention across diverse global communities and populations, including gender-diverse populations, was one of the key recommendations from the PURPOSE 2 Global Community Advisory Group (G-CAG) and other community members.

Consequently, the study enrolled participants from seven countries across four continents and was the first phase III HIV prevention trial to intentionally include transgender men and non-binary individuals.

Gilead expects data from both trials to support a series of global regulatory filings for lenacapavir for PrEP (expected to begin by the end of 2024).

A Potential Approval Should Boost GILD

Gilead is a dominant player in the HIV market.  Biktarvy is the number one prescribed regimen for both treatment-naïve and switch patients.

It continues to maintain its dominant position with an increasing market share for treatment and prevention. Gilead projects HIV sales to grow 4% in 2024.

Lenacapavir is already approved under the brand name Sunlenca in the United States for the treatment of HIV-1 infection in heavily treatment-experienced adults with multi-drug-resistant infections.

At present, there are two FDA-approved daily oral medications for PrEP — Truvada and Descovy.

Please note that Descovy for PrEP is indicated in at-risk adults and adolescents (≥35 kg) to reduce the risk of sexually acquired HIV-1 infection, excluding individuals at risk from receptive vaginal sex.

Truvada is a two-drug combination of emtricitabine and tenofovir disoproxil fumarate, approved for the treatment of HIV-1 infection and PrEP.

The strong results increase the probability of lenacapavir’s approval that should further solidify GILD’s HIV franchise. Lenacapavir has a competitive advantage as it needs to be taken only twice yearly, unlike daily oral pills, and addresses a broad population.

Lenacapavir is already approved under the brand name Sunlenca in the United States for the treatment of HIV-1 infection in heavily treatment-experienced adults with multi-drug resistant infection.

A long-acting injectable form of PrEP was also approved by the FDA. In 2021, the regulatory body approved ViiV Healthcare’s Apretude (cabotegravir extended-release injectable suspension) for use in at-risk adults and adolescents weighing at least 35 kilograms for PrEP to reduce the risk of sexually acquired HIV.

ViiV Healthcare is a global specialist HIV company, majorly owned by GSK plc (GSK Quick QuoteGSK - Free Report) , with Pfizer (PFE Quick QuotePFE - Free Report) and Shionogi as shareholders. The company was formed by GSK and Pfizer in 2009.

Apretude is given first as two initiation injections, administered a month apart and then every two months. Patients in need can either start their treatment with Apretude or take oral cabotegravir (Vocabria) for four weeks to understand how well they can tolerate the drug.

GSK is a key competitor for GILD in the HIV market. GSK posted 13% growth in HIV sales in the second quarter, driven by strong patient demand for two drug regimens — Dovato and Juluca — and long-acting drugs (Cabenuva and Apretude).