New HIV vaccine trial finds it effective in 99% of cases

Researchers at Emory University have conducted clinical trials of a new drug, Lenacapavir, to prevent HIV infection. The work, supported by the pharmaceutical company Gilead Sciences, was published in the New England Journal of Medicine. It proves that the vaccine can protect even vulnerable populations from the virus.

Clinical trials were conducted with 3,265 participants from different countries including the US, South Africa, Mexico, Brazil and Thailand. Participants were randomly divided into two groups: the first received injections of Lenacapavir every 26 weeks, while the second group took the antiretroviral drug Truvada daily. Of the 2,179 people who took Lenacapavir, two (less than one percent) ended up infected. In the second group, nine people out of 1,086 (17 percent) became infected.

It is known that the effectiveness of antiretrovirals depends on strict adherence, but many people stop taking the pills daily after a year due to social and economic factors. The main advantage of “Lenacapavir” is that it can be administered subcutaneously only twice a year.

“Lenacapavir acts as an inhibitor to prevent the breakdown of the capsid, the protein shell that protects the genetic material of the virus and facilitates its delivery to the target cell. Once inside the cell, the capsid breaks down, releasing the viral genome into the cytoplasm, where the virus begins to utilize cellular resources for its reproduction. In contrast, pre-exposure prophylaxis drugs such as Truvada and Descovy work through a different mechanism: they block the reverse transcriptase enzyme, which is responsible for introducing viral genes into the host cell's DNA.

The results show that twice-daily injections reduce the risk of infection by 96% compared to conventional prevention methods. The scientists said they hope the new drug will be approved for commercial use as early as 2025 and will be part of a pre-exposure prophylaxis that prevents anyone who has had an injection from contracting the virus sexually. For now, however, researchers cite increasing the affordability of the drug as the most important challenge, as the cost of an annual dose of the vaccine exceeds $40,000.

 The study is a continuation of the phase 3 double-blind, randomized PURPOSE 1 trial conducted by Gilead Sciences, Inc. A previous clinical trial demonstrated that Lenacapavir was 100% effective in preventing HIV infection and was superior to all available drugs.

According to the World Health Organization, by 2023, AIDS caused by the human immunodeficiency virus has caused about 40.4 million people to pass away. During the same period, approximately 39 million people worldwide are living with HIV, of whom 29.8 million are on antiretroviral therapy. In 2022, about 630,000 people passed away because of AIDS.