Injectable Lenacapavir for PrEP

Last Updated: 8 July 2024

Injectable lenacapavir (LEN) is an investigational antiretroviral (ARV) drug that is being studied as a potential PrEP product. Below are details on its distinct characteristics and ongoing Phase II and III clinical trials, as well as resources to learn more.

The Basics

• Given every six months.
• Two subcutaneous injections given on the same visit in the abdomen.
• Developed by Gilead.
• Approved in multiple countries as treatment under the brand name Sunlenca.
• Currently under investigation for use as prevention in two large Phase III clinical trials, PURPOSE 1 and PURPOSE 2. Early results from PURPOSE 1 showed no HIV infections in the LEN for PrEP arm.
• Three smaller Phase II clinical trials PURPOSE 3, PURPOSE 4, and PURPOSE 5 are investigating safety and efficacy in populations not included in PURPOSE 1 and 2.

The Trials

PURPOSE 1

• Conducted among approximately 5,000 cisgender women in South Africa and Uganda.
• Testing the efficacy of both LEN for PrEP and the daily pill emtricitabine/tenofovir alafenamide (F/TAF) in preventing HIV.
• In June 2024, the trial was unblinded after meeting its primary endpoint of superiority to oral PrEP (TDF/FTC) and background HIV incidence.
• Scheduled to run until July 2027.
• The first Phase III clinical trial to include pregnant and lactating people from the start—which could make it easier to get approval for use in this population if found to be effective and safe.
• More details here.

PURPOSE 2

• Conducted among 3,000 men who have sex with men, gay men, transgender men, transgender women, and gender non-binary people in Argentina, Brazil, Mexico, Peru, Puerto Rico, South Africa, Thailand, the USA, and Vietnam.
• Scheduled to run until April 2027.
• More details here.

PURPOSE 3

• Conducted among 250 cisgender women in the USA.
• Scheduled to run until January 2028.

PURPOSE 4

• Conducted among 250 people who inject drugs in the USA.
• Scheduled to run until July 2027.

PURPOSE 5

• Exact population and timeframe still to be announced, but will be conducted among people who may benefit from but are not yet taking PrEP in France and the United Kingdom.

Further Resources

• The Lens on LEN — AVAC’s primer on lenacapavir
• AVAC’s press release on the PURPOSE 1 trial interim results
• Gilead’s press release on the PURPOSE 1 trial interim results
• Visit our study dashboard for more details on LEN for PrEP clinical trials.