Twice-yearly injectable lenacapavir, an HIV-prevention drug, reduces risk by 96%

In September, Gilead Sciences announced that Lenacapavir, the twice-yearly injectable HIV-1 capsid inhibitor, demonstrated superiority to the once-daily Truvada in a recent Phase 3 clinical trial. It was one of two Phase 3 trials halted early due to successful results.

Both Phase 3 trials used background HIV (bHIV), or the expected incidence of HIV without the use of PrEP, as the primary comparator, and used Truvada as a secondary comparator.

The Independent Data Monitoring Committee (DMC) halted the trials during interim analysis after determining they had met key efficacy endpoints early.

“With such remarkable outcomes across two Phase 3 studies, lenacapavir has demonstrated the potential to transform the prevention of HIV and help to end the epidemic,” Daniel O’Day, chairman and CEO of Gilead, said in a statement.

Purpose 1, the first Phase 3 trial, took place in June of 2024 and measured the effectiveness of lenacapavir in cisgender women of the sub-Saharan Africa.

Purpose 2, the second Phase 3 trial, included cisgender and transgender men, transgender women, and gender non-binary individuals in Argentina, Brazil, Mexico, Peru, South Africa, Thailand, and the United States, and who engage in sexual relations with partners assigned male at birth. 2,180 participants used lenacapavir and 1,087 participants used Truvada. There were only two reported incidents of HIV in the lenacapavir test group versus nine in the Truvada group. Lenacapavir also showed a reported 96 percent relative risk reduction versus bHIV.

Gilead and the study’s researchers see lenacapavir as a potential milestone in the battle against HIV.

“In the United States, the stubbornly high rate of HIV diagnoses — especially in the U.S. South, and particularly among gay and bisexual men of color and transgender people — demands novel approaches to help people prevent HIV acquisition,” said Colleen Kelley, MD, MPH, Professor of Medicine at Emory University and a principal investigator in the Purpose 2 Phase 3 trial. “Because adherence to oral products can be challenging for some people, twice-yearly injectable lenacapavir for PrEP has the potential to be one of the most impactful interventions we could have to drive down new infections and bring us closer to ending the HIV epidemic in the United States.”

Lenacapavir’s price right now for use as HIV treatment is $3,450 per month, according to NBC News. The outlet reports that Gilead hasn't set a different price for use as PrEP. A Gilead spokesperson told NBC News "that the reference point for the price of lenacapavir as PrEP will not be its current use as treatment. It remains unclear whether that statement signals a willingness on the part of the pharmaceutical giant to bring the injectable drug’s price down closer to Earth for its use as HIV prevention."