Injectable HIV Prevention Drug Shows Promising Results in Clinical Trials

By Thuku Kariuki and Daniel Furnad

An injectable medication to prevent the transmission of HIV, taken twice a year, has successfully passed the first clinical trial in South Africa and Uganda. 

Lenacapavir, developed by Gilead Sciences, a research-based biopharmaceutical company in the US, will mark a significant advancement in the global fight against HIV if proven efficient.

 Four studies are scheduled to determine how the drug works for vulnerable populations. 5300 cisgender young African women and adolescents between 16 and 26 from the two countries were enrolled in the just completed PURPOSE 1 HIV prevention trial. The study evaluates injectable lenacapavir for PrEP and daily oral emtricitabine/tenofovir alafenamide (F/TAF) for PrEP. No new infections were reported among participants who received the injection.

Three more studies will be rolled out in the next year and a half. A companion trial, PURPOSE 2, is ongoing in Argentina, Brazil, Mexico, Peru, South Africa, Thailand and the US. The second trial is testing twice-yearly lenacapavir for PrEP among cisgender men who have sexual relations with men, transgender women, transgender men, and gender non-binary people. Results from PURPOSE 2 are expected by early 2025.  

PURPOSE 3 will focus on cisgender women in the USA, whole PURPOSE 4 will study intravenous drug users. At some stage, Gilead Sciences will present its findings to regulatory agencies, such as the Food and Drug Administration (FDA) in America, for general approval.

HIV activist organizations, like the AIDS Vaccine Advocacy Coalition (AVAC) in the USA, see these initial results as ground-breaking.

"We are incredibly excited about this result, especially about what it can mean for women in Africa," says Nandisile Sikwana, Regional Stakeholder Engagement Manager for AVAC.

"This is one of the most important results we've seen to date in an HIV prevention study," adds Mitchell Warren, AVAC's executive director.

7.2 percent of women in Uganda have contracted HIV. 19 percent of South African adults between 15 and 49 years are infected. Therefore, zero new infections among more than 5000 participants in the trial is remarkable.

 The American Center for Disease Control recommends Pre-Exposure Prophylaxis (PrEP) for all groups at risk of exposure to the human immunodeficiency virus. The CDC's campaign to fight the spread of the virus in the USA emphasizes PrEP coverage and has seen its use expand from about 13 percent in 2017 to 50 percent today.

While Prophylaxis has been available for the past 14 years, PrEP medication is usually administered orally. This mode of administration may lead to missed doses, especially for individuals who pay less attention to their calendars. Having injectable medicines, such as lenacapavir, is seen as a much more effective way to prevent HIV transmission.

AVAC officials are concerned that lenacapavir be made available among a broad spectrum of communities in the developed and developing world. AVAC's Warren urged action by the United Nations, saying, "We also call on WHO to be prepared to quickly include lenacapavir, if approved by regulatory agencies, in HIV prevention guidelines. There is no time to waste if we are to translate these exciting clinical trial results into actual public health impact and expand the toolbox of HIV prevention choices."

AVAC is looking to mobilize the assistance of civil society organizations, national governments, and international donors to make lenacapavir widely available quickly. They hope that lessons learned from the rollout of daily oral PrEP, and more recently, the dapivirine vaginal ring and injectable cabotegravir, will help speed regulatory approval and guideline development in key countries. They are rallying various organizations to work together to design effective programs and promote community understanding of and acceptance of lenacapavir for PrEP.

The days when HIV was a death sentence are long gone. But soon, the world may be able to shield its most vulnerable populations from the pain and stigma that the virus brings. This successful study should spur organizations across the globe to protect against further transmissions, benefitting community health, wealth, and social unity.