Twice-yearly injection is 96% effective at HIV prevention
In order for oral antiretrovirals that prevent HIV infection to be effective, they must be taken daily as directed. Now, results from a phase 3 clinical trial have indicated that a twice-yearly injection offers a 96% reduced risk of infection overall, making it significantly more effective than daily medication.
The randomised, double-blind clinical trial compared the efficacy of a common oral pre-exposure prophylaxis (PrEP) medication, known as Truvada, against Gilead Sciences’ twice-yearly injectable HIV-1 capsid inhibitor, known as lenacapavir. The study was funded by Gilead and led by physicians at Emory University and Grady Health System, with results published in The New England Journal of Medicine.
During the trial, only two participants in the lenacapavir group, which comprised 2179 people, acquired HIV. This compares to nine new HIV infections in the Truvada group, which had 1086 people. The trial showed that adherence to the injectable was higher than of the daily oral pill.
“Seeing these high levels of efficacy — at almost 100% — in an injectable that people only have to take every six months is incredible,” said Colleen Kelley, lead author of the study and a professor at Emory University. “This is a considerable and profound advancement in medicine, especially for people whose circumstances don’t allow them to take a daily oral medication, and for those among populations disproportionately impacted by HIV.”
Kelley, who is also the Co-Director of the Emory Center for AIDS Research, said that while PrEP is incredibly effective at preventing infection, part of what made the injection more effective in the clinical trial was the challenges associated with adherence to a daily oral pill.
“What we see over time is that about half of people who start taking daily oral PrEP stop within a year due to various factors,” she said. “Having an effective injectable that is only needed twice annually is very significant for people who have trouble accessing health care or staying adherent to daily oral pills.”
The trial groups comprised cisgender men and gender-diverse people at 88 sites in Peru, Brazil, Argentina, Mexico, South Africa, Thailand and the US. The inclusion of racially, ethnically and gender-diverse participants is representative of populations disproportionately impacted by HIV in real time, as well as those that have limited access to PrEP or may have difficulty consistently taking the medication.
“We are not reaching everyone we need to reach with our current HIV prevention interventions, such as those who are disproportionately impacted by HIV and healthcare disparities,” Kelley said. “For people that are unable to take the daily oral pills, the injectable agents can really give incredible efficacy and be a game changer in helping them stay HIV negative.”
With the phase 3 clinical trial now completed and submitted to the FDA for consideration, the researchers are hopeful that Lenacapavir may be approved by 2025 for commercial use.
“Long-acting antiretrovirals offer new hope for those who are not able to take oral medications,” said Dr Carlos del Rio, Director of the Emory Center for AIDS Research. “The challenge is now to roll out and make these tools available and accessible in an equitable way — only then we will see new HIV infections dramatically decreased locally and globally.”
Image credit: iStock.com/Liudmila Chernetska