Milestone: First Twice-Yearly HIV Preventive Therapy Achieves Zero Infections

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Milestone: First Twice-Yearly HIV Preventive Therapy Achieves Zero Infections

Milestone: First Twice-Yearly HIV Preventive Therapy Achieves Zero Infections

On June 20, Gilead Sciences announced the top-line results of a pivotal Phase 3 clinical trial, PURPOSE 1. The interim analysis revealed that the HIV-1 capsid inhibitor lenacapavir, administered biannually, demonstrated 100% efficacy in preventing HIV infections among cisgender women.

Milestone: First Twice-Yearly HIV Preventive Therapy Achieves Zero Infections

Image Source: Gilead Official Website

This is the first Phase 3 clinical trial in HIV prevention to show zero infections. Dr. Merdad Parsey, Gilead Sciences’ Chief Medical Officer, remarked that the results indicate lenacapavir’s potential to be a groundbreaking preventive measure against HIV when administered twice a year. He expressed optimism about further findings from ongoing PURPOSE trials, which aim to contribute to the global fight against HIV.

First HIV Prevention Drug Achieves Zero Infections in Late-Stage Trial

Gilead Sciences is renowned for developing antiviral drugs and has already received approval in China for two HIV pre-exposure prophylaxis (PrEP) medications: emtricitabine/tenofovir disoproxil fumarate (Truvada) in 2020 and emtricitabine/tenofovir alafenamide (Descovy) earlier this year.

The PURPOSE 1 trial is a double-blind, randomized Phase 3 study assessing the safety and efficacy of subcutaneous lenacapavir (administered twice yearly) versus daily oral Descovy (emtricitabine 200mg/tenofovir alafenamide 25mg). The trial involved over 5,300 cisgender women and adolescent girls aged 16-25 from 25 locations in South Africa and three in Uganda, who were randomized into lenacapavir, Descovy, and Truvada groups in a 2:2:1 ratio. Remarkably, no HIV infections occurred among the 2,134 women in the lenacapavir group (incidence rate: 0.00 per 100 person-years).

Gilead reported that PURPOSE 1 met its primary efficacy endpoint, demonstrating the superiority of lenacapavir administered twice yearly compared to daily Truvada and the background HIV infection rate. Lenacapavir was well-tolerated with no significant new safety concerns.

Detailed data from the PURPOSE 1 trial will be presented at future conferences. Gilead is also conducting other key trials for lenacapavir, with results from the PURPOSE 2 study expected by late 2024 or early 2025. PURPOSE 2 evaluates the efficacy of biannual lenacapavir in men who have sex with men (MSM) and other groups across Argentina, Brazil, Mexico, Peru, South Africa, Thailand, and the United States. Positive results from these studies could lead to regulatory approval for lenacapavir as a PrEP option for various high-risk groups and communities.

Dr. Linda-Gail Bekker, Director of the Desmond Tutu HIV Centre at the University of Cape Town and former President of the International AIDS Society, commented that while traditional PrEP medications are highly effective when taken as prescribed, lenacapavir’s biannual administration could address challenges related to the stigma and discrimination associated with oral PrEP and improve adherence and continuity in PrEP usage.

A New Dawn in the Fight Against AIDS

The fight against AIDS has been challenging due to the lack of a cure and difficulties in control. Currently, no curative medications or preventive vaccines exist. Post-exposure prophylaxis (PEP) within 72 hours of high-risk exposure remains the last line of defense against HIV infection.

Once diagnosed, individuals must undergo lifelong antiretroviral therapy (ART), which often leads to issues such as drug resistance and poor patient adherence. According to the United Nations, over half of the global HIV population receives ART.

Experts emphasized that early detection and treatment are crucial for reducing viral loads, promoting immune reconstruction, and lowering the incidence of AIDS-related opportunistic infections or tumors. Early treatment also helps reduce HIV transmission and alleviates the economic burden on individuals and society.

Due to the challenges in developing an effective AIDS vaccine, research has shifted towards long-acting formulations. experts also stated that inconsistent adherence to ART can lead to insufficient drug levels in the body, reducing viral suppression and increasing the risk of drug resistance. Long-acting formulations can lower the frequency of administration, maintain effective drug levels, and improve adherence.

Gilead’s announcement has garnered significant global attention. If approved by the FDA, lenacapavir would become an important new option for HIV prevention. PrEP is a crucial tool in preventing HIV infection, and lenacapavir’s advantage lies in its biannual administration, which enhances adherence.