June 22, 2024

Groundbreaking HIV prevention drug shows 100% efficacy 

Groundbreaking HIV prevention drug shows 100% efficacy 

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By Shola Ogundipe

A promising new HIV prevention drug called lenacapavir has shown 100 percent efficacy in a clinical trial among adolescent girls and young women in South Africa and Uganda.

The twice-yearly injection was found to be superior to daily Truvada, the current standard for pre-exposure prophylaxis (PrEP). This is according to Gilead Sciences, the developer of lenacapavir.

In a release signed by Kay Marshall, Senior Communications Advisor for AVAC, the organization welcomes the groundbreaking results of the PURPOSE 1 study which enrolled over 5,300 cisgender adolescent girls and young women ages between the age of 16 and 26 in South Africa and Uganda.

The study evaluated injectable lenacapavir for PrEP and daily oral emtricitabine/tenofovir alafenamide (F/TAF) for PrEP.

An independent data and safety monitoring board (DSMB), at a scheduled review of the trial data, found the regimen to be safe and highly effective, with no infections seen among trial participants who received injectable lenacapavir. 


HIV prevention advocate and AVAC’s executive director, Mitchell Warren hails the lenacapavir trial results as a significant advancement. He emphasized the potential of long-acting injectables to increase adherence, improve access, and reduce strain on healthcare systems.

“We expect to see a timeline that takes into account a full analysis of PURPOSE 1 data and the coming data from PURPOSE 2 from Gilead as soon as possible, and we urge regulatory agencies to prepare to fast track regulatory review.

“We look forward to working with civil society partners, Gilead, international donors, normative agencies and national governments to ensure that this groundbreaking HIV prevention option is made available as quickly as possible and that we don’t squander this opportunity to drive down new HIV infections,” Warren said. 

The Regional Stakeholder Engagement Manager for AVAC, and a member of the PURPOSE 1 Global Community Advisory Group, Nandisile Sikwana said, “We are incredibly excited about this result, especially about what it can mean for women in Africa. We applaud Gilead’s commitment to Good Participatory Practice in this and the other PURPOSE studies. 

“While we wait for full data from the study, including adherence data of oral F/TAF, it is imperative that planning for rollout of lenacapavir be accelerated. We know that even with the most ambitious timeline, it will take time for lenacapavir to be rolled out”. 

A companion trial, PURPOSE 2, is underway in Argentina, Brazil, Mexico, Peru, South Africa, Thailand and the US, testing twice-yearly lenacapavir for PrEP among cisgender men who have sex with men, transgender women, transgender men, and gender non-binary people. Results from PURPOSE 2 are expected by early 2025. 

… additional studies

Additional studies in critical populations, including PURPOSE 3 among cisgender women in the US and PURPOSE 4 among people who use injection drugs, are also underway, and it will be imperative to understand how today’s results influence these trials. 

Gilead’s plans for submission to regulatory agencies and future access, including the US Food and Drug Administration (FDA), are not yet clear. But the results reported today make this urgent. 

“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,” he continued. 

“We now know that lenacapivir for PrEP is safe and highly effective among women. Even as we await the results of the trial among other essential populations and for regulatory submission and review, there is urgent work to be done now by communities, policymakers, funders and program implementers to design and build HIV prevention programmes and prepare health systems to deliver the growing array of biomedical PrEP options, including the addition of twice-yearly injectable lenacapavir.

“The full range of PrEP products – including oral PrEP – must be made feasible choices for all people who need and want HIV prevention options,” Sikwana added.

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