Gilead shares positive Phase 3 results for biannual HIV PrEP drug in women

Gilead Sciences has announced that its biannual injectable pre-exposure prophylaxis (PrEP) drug, lenacapavir, has shown complete efficacy in preventing human immunodeficiency virus (HIV) in women, based on late-stage clinical trial results. The phase 3 PURPOSE 1 study included over 5,300 female and adolescent participants aged between 16 and 25 from South Africa and Uganda. These participants were randomly assigned to either receive lenacapavir or one of Gilead’s daily oral PrEP medications, which include Descovy (emtricitabine/tenofovir alafenamide) and Truvada (emtricitabine/tenofovir disoproxil fumarate).

Among the 2,134 women who were administered lenacapavir, there were no new HIV infections, while there were 16 new cases among the 1,068 participants who were given Truvada. This demonstrated that lenacapavir's biannual dosage was superior to the standard background HIV incidence (bHIV). Additionally, the HIV incidence rates in the Descovy group were similar to those in the Truvada group, and neither was statistically superior to bHIV. Lenacapavir was generally well tolerated, with no significant or novel safety issues reported.

Given these compelling results, an independent data monitoring committee has advised Gilead to discontinue the blinded phase of the trial and offer lenacapavir openly to all participants. Merdad Parsey, Gilead’s chief medical officer, highlighted the significance of these findings, noting that having zero infections and achieving 100% efficacy positions lenacapavir as a vital new tool in the prevention of HIV. He expressed optimism about forthcoming results from the ongoing PURPOSE clinical program and Gilead’s continuous efforts to end the HIV epidemic globally.

PrEP is known to be highly effective in preventing HIV when taken consistently as prescribed. However, daily oral therapies often face adherence challenges, partly due to the stigma associated with the treatment and the need for persistent daily intake. Lenacapavir's biannual dosing schedule could potentially overcome these barriers and improve adherence rates, making it a more practical option for many individuals.

Lenacapavir, marketed under the brand name Sunlenca, was approved by the U.S. Food and Drug Administration (FDA) in 2022. It is prescribed in combination with other antiretroviral drugs for adults who have significant treatment experience and are dealing with multi-drug-resistant HIV-1 infections. The hope is that lenacapavir, when used for PrEP, will similarly help to address treatment challenges and increase adherence, thanks to its twice-yearly administration.

These promising results for lenacapavir come on the heels of another encouraging study from Gilead, which announced positive outcomes from an open-label extension study of their experimental PPAR delta agonist, seladelpar, for patients with primary biliary cholangitis just a month earlier.