Injectable PrEP continues to show promising results

A twice-yearly injectable form of the HIV prevention medication known as PrEP slashed infections by 96% in a clinical trial, outperforming the effectiveness of PrEP’s daily pill option.

The research, announced by Gilead Sciences, represents yet another critical investigation of the effectiveness of the injectable form of PrEP, which could serve as a pivotal tool in the fight against HIV because it does not require individuals to take a pill every day. 

There are now multiple forms of injectable PrEP medications. Lenacapavir, which is Gilead’s injectable drug, differs from ViiV Healthcare’s Apretude, or cabotegravir, which is also an injectable form of PrEP but is administered once every other month instead of twice annually.

The Food and Drug Administration (FDA) approved Apretude’s injectable PrEP option in 2021, but many candidates have not yet gravitated towards it because of a high price tag and regulations stipulating that health insurers only need to cover oral PrEP for the time being. However, last summer the U.S. Preventive Services Task Force gave injectable PrEP an “A” rating, paving the way for the Affordable Care Act to require it to be covered by 2025.

Lenacapavir, the twice-annual injectable option, has already been utilized for the purpose of treating drug-resistant HIV. Gilead hopes to get FDA approval to use lenacapavir for PrEP later this year with the possibility of debuting it by the middle or end of next year.

A previous trial run to test the effectiveness of lenacapavir as injectable PrEP indicated that it was 100% effective in preventing HIV among more than 5,000 young cisgender women in Africa.

In a follow-up trial, researchers compared injectable PrEP to oral PrEP among 3,200 cisgender men, transgender men, transgender women, and non-binary individuals 16 years of age or older who have sex with individuals assigned male at birth in Argentina, Brazil, Mexico, Peru, South Africa, Thailand, and the United States. Among the 2,180 people who took lenacapavir as injectable PrEP, there were two “incident cases,” and 99.9% of people did not acquire HIV, according to Gilead. Among those who took Truvada as oral PrEP, there were nine “incident cases” among 1,087 individuals on Truvada.

Referring to background HIV, also known as bHIV — which measures the anticipated HIV rates without using PrEP — researchers concluded that lenacapavir offered a 96% drop in risk compared to bHIV.

“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,” said Daniel O’Day, who is the chair and chief executive officer of Gilead. “Now that we have a comprehensive dataset across multiple study populations, Gilead will work urgently with regulatory, government, public health and community partners to ensure that, if approved, we can deliver twice-yearly lenacapavir for PrEP worldwide, for all those who want or need PrEP.”

Reducing racial disparities is a key issue in the fight against HIV. Although the FDA approved PrEP more than a decade ago, research showed that by 2019, just 8% of Black people and 14% of Latinx individuals eligible for PrEP received prescriptions for it, compared to 63% of white people.

Other concerns about PrEP include the difficulty of adhering to a daily pill regimen. That challenge has been apparent by the way some health departments have proposed a PrEP-on-demand schedule in which people take the medication around the time when they have sex.

However, some warn that an injectable option may not necessarily translate into broader access and greater uptake. In a written statement, PrEP4All — a non-profit fighting for greater access to HIV prevention medication — said ViiV’s long-acting injectable has had very poor uptake several years after FDA approval. PrEP4All said the same fate could await Gilead’s injectable PrEP option given that the pharma giant’s HIV prevention drugs have been far too expensive and primarily only benefitted white cisgender men. 

“No status quo approach will result in anything close to equitable access to lenacapavir as PrEP,” PrEP4All said. “This is a moment for advocates and policy makers to forcefully get behind the movement for a National PrEP Program and support a pathway to reasonable public health pricing for lenacapavir.”