HIV prevention in cisgender women shows promising interim results from Gilead Sciences’ Phase III PURPOSE 1 trial, which evaluates the efficacy of the twice-yearly injectable HIV-1 capsid inhibitor, lenacapavir. The company reports that lenacapavir demonstrated a 100% efficacy rate, making it superior to once-daily oral Truvada (emtricitabine 200 mg and tenofovir disoproxil fumarate 300 mg). Consequently, an independent Data Monitoring Committee has recommended that Gilead end the blinded phase of the trial and start administering open-label lenacapavir to all participants.
“With zero infections and 100% efficacy, twice-yearly lenacapavir has demonstrated its potential as an important new tool to help prevent HIV infections,” said Merdad Parsey, MD, PhD, chief medical officer of Gilead Sciences. “We look forward to additional results from the ongoing PURPOSE clinical program and continuing toward our goal of helping to end the HIV epidemic for everyone, everywhere.”
The double-blind, randomized PURPOSE 1 trial is assessing the safety and efficacy of twice-yearly subcutaneous lenacapavir for pre-exposure prophylaxis (PrEP) compared to once-daily oral Descovy (emtricitabine 200 mg and tenofovir alafenamide 25 mg). The trial enrolled over 5,300 cisgender women and adolescent girls aged 16-25 years from South Africa and Uganda. Participants were divided into three groups: one receiving twice-yearly lenacapavir, another taking once-daily oral Descovy, and a third group taking once-daily oral Truvada. The primary endpoint was to determine the superiority of twice-yearly lenacapavir over the background HIV incidence (bHIV), with a secondary endpoint of superiority over Truvada.
Lenacapavir Shows Zero HIV Infections in Phase III Trial, Promising Alternative to Daily PrEP
The results showed that in the lenacapavir group, zero HIV infections were reported among 2,134 women. In contrast, the Truvada group reported 16 cases out of 1,068 women, and the Descovy group reported 39 cases out of 2,136 women, which was not superior to bHIV. These findings suggest that lenacapavir could improve adherence and reduce the stigma associated with daily oral PrEP regimens. More data from the trial will be announced at a later date.
Lenacapavir, Descovy, and Truvada were generally well-tolerated, with no new safety signals emerging from the trial. Common adverse events in the Descovy cohort included diarrhea, nausea, headache, fatigue, and abdominal pain. Results from PURPOSE 2, which evaluates different populations including cisgender men and transgender individuals from Argentina, Brazil, Mexico, Peru, South Africa, Thailand, and the United States, are expected later this year or in early 2025. These trials are anticipated to support regulatory filings to expand lenacapavir’s approval across diverse populations.
“Twice-yearly lenacapavir for PrEP, if approved, could provide a critical new choice for HIV prevention that fits into the lives of many people who could benefit from PrEP around the world—especially cisgender women,” said Linda-Gail Bekker, MBChB, DTM&H, DCH, FCP(SA), PhD, director of the Desmond Tutu HIV Center at the University of Cape Town, South Africa, and past president of the International AIDS Society. “While we know traditional HIV prevention options are highly effective when taken as prescribed, twice-yearly lenacapavir for PrEP could help address the stigma and discrimination some people may face when taking or storing oral PrEP pills, as well as potentially help increase PrEP adherence and persistence given its twice-yearly dosing schedule.”
Gilead’s Lenacapavir Shows 100% Efficacy in HIV Prevention Trial for Cisgender Women
Currently, neither lenacapavir nor Descovy has been approved for the prevention of HIV in cisgender women by any regulatory body globally. Gilead Sciences’ Phase III PURPOSE 1 trial for lenacapavir has shown groundbreaking interim results, demonstrating 100% efficacy in preventing HIV in cisgender women. This trial is significant because it highlights the potential of lenacapavir as a twice-yearly injectable option for HIV prevention, providing an alternative to daily oral medications like Truvada and Descovy. The trial’s success led an independent Data Monitoring Committee to recommend transitioning all participants to open-label lenacapavir.
The PURPOSE 1 trial, involving over 5,300 cisgender women and adolescent girls from South Africa and Uganda, compared the efficacy of twice-yearly lenacapavir with daily oral Truvada and Descovy. The lenacapavir group reported zero HIV infections, while the Truvada and Descovy groups had 16 and 39 infections, respectively. These results underscore lenacapavir’s potential to improve adherence to HIV prevention regimens and reduce the stigma associated with daily pills.
Safety profiles for lenacapavir, Descovy, and Truvada were consistent, with no new safety concerns. Common side effects included diarrhea, nausea, headache, fatigue, and abdominal pain. Further results from the PURPOSE 2 trial, which includes a more diverse population, are expected soon and will support regulatory filings to broaden lenacapavir’s approval. Experts like Linda-Gail Bekker highlight the importance of lenacapavir in providing a flexible and less stigmatizing option for HIV prevention, particularly for cisgender women. The success of lenacapavir in this trial marks a significant step towards expanding effective HIV prevention methods and addressing the global HIV epidemic.
Resource: Gilead, June 21, 2024
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