100% efficacy in HIV prevention for teens taking powerful drug lenacapavir
Researchers at the Conference on Retroviruses and Opportunistic Infections (CROI) shared exciting news about the efficacy of the long-acting injectable lenacapavir for HIV prevention when tested with cisgender women age 16 – 17: zero HIV infections among study participants who received twice-yearly medication doses on schedule, and medication that proved to be safe and well-tolerated.
“This study is breaking new ground in HIV prevention–especially for adolescents,” explained Dr. Katherine Gill from Desmond Tutu Health Foundation. “Due to strict ethical and regulatory guidelines, adolescents are oftentimes excluded from HIV prevention studies, which can delay their access to new effective prevention options. PURPOSE I is the first large-scale phase III HIV prevention study to intentionally include 16 and 17 year olds from the beginning, ensuring that they aren’t kept waiting for years after adult approval for access to prevention.”
The PURPOSE I study is a double-blind, randomized study that included more than 5,300 cisgender women from South Africa and Uganda; there were a total of 124 adolescents included in the trial (age 16-17). Of the adolescents, 56 received lenacapavir injections every 26 weeks, 45 received F/TAF (tenofovir alafenamide fumarate/emtricitabine, used for oral PrEP and sold under the brand name Descovy); and 23 received F/TDF (tenofovir disoproxil fumarate/emtricitabine, used for oral PrEP and sold under the brand name Truvada).
There were zero HIV infections that occurred among adolescents receiving any of the study medications, including among those who received long-acting lenacapavir over the more than 52 weeks of the study.
Lenacapavir injections were safe and well-tolerated, with adverse events such as injection site pain and injection site nodules occurring with about the same prevalence between adults and adolescents. There were no adverse events which led to adolescents receiving lenacapavir to stop the study.
The researchers also measured the plasma (blood) concentration of lenacapavir at the 26-week mark, and found that the “trough,” or lowest medication levels, were similar to those of adult participants (31.1 ng/mL median for adolescents compared to 29.8 ng/mL for adults).
Gill emphasized the thoughtful process the study team used to engage the community before including young people in the study, explaining that they engaged with adolescent medicine experts and community advocates to build procedures for seeking consent and other study activities.
“This early and continuous engagement allowed us to challenge the traditional approach of prioritizing adults before adolescents,” said Gill. “By collaborating with regulators, rapidly reviewing adult safety data, and working with local ethics committees in South Africa and Uganda, we were able to accelerate adolescent involvement while ensuring the study was ethically sound and in line with community needs.”
Long-acting injectable lenacapavir is a capsid inhibitor which is currently approved by the FDA for the treatment of HIV and currently being tested as a method of PrEP. Gilead Sciences, the drug’s manufacturer, submitted approval for the drug’s use as PrEP at the end of 2024 and approval for HIV prevention is eagerly anticipated in 2025.
