Gilead Claims 96% HIV Risk Cut With Semiannual PrEP, Plans Regulatory Filings

Gilead Sciences is advancing its efforts to secure regulatory approval for lenacapavir as a pre-exposure prophylactic (PrEP) treatment for HIV, following promising interim results from its Phase III PURPOSE 2 trial. The trial focused on a diverse group of individuals, including cisgender and transgender men, transgender women, and gender non-binary individuals who have sex with partners assigned male at birth.

The interim results from PURPOSE 2 revealed that lenacapavir, administered as a twice-yearly injection, significantly reduced the risk of HIV infection by 96% compared to its background incidence. Out of the 2,180 participants in the study, only two contracted HIV, indicating that 99.9% of participants were free from the infection at the time of analysis.

Moreover, lenacapavir outperformed the daily regimen of Truvada (emtricitabine/tenofovir) for HIV PrEP, showcasing its potential as a superior alternative. An independent data monitoring committee validated that the PURPOSE 2 trial achieved its primary efficacy endpoint, leading to the recommendation to end the blinded phase of the study and offer open-label lenacapavir to all participants.

Gilead's CEO, Daniel O’Day, described the results as "remarkable" and emphasized the drug’s potential to revolutionize HIV prevention and contribute to ending the epidemic. He underscored the company's commitment to working with regulatory bodies, governments, public health organizations, and community partners to make lenacapavir widely available if approved.

Gilead is planning to initiate global regulatory submissions by the end of this year, aiming for an initial product launch in 2025. Lenacapavir functions as a selective inhibitor of the HIV-1 capsid, which disrupts various stages of the virus’s life cycle, including its assembly and release from infected host cells. This mechanism differentiates it from other antiviral HIV drugs that typically target only one stage of the viral replication process. Importantly, lenacapavir has demonstrated no cross-resistance to existing drug classes, enhancing its appeal as an innovative HIV treatment.

Previously, in August 2022, lenacapavir received its first approval from the European Commission for twice-yearly treatment of adults with multidrug-resistant HIV, marketed under the name Sunlenca. However, its use as a PrEP treatment remains investigational and has yet to receive regulatory clearance.

To substantiate the PrEP application, Gilead is conducting the Phase III PURPOSE program, which includes the PURPOSE 1 trial. In June 2024, Gilead released data from PURPOSE 1, demonstrating 100% efficacy for twice-yearly lenacapavir. None of the 2,134 women who received lenacapavir contracted HIV, in contrast to 16 out of 1,068 women in the Truvada group and 39 out of 2,136 women who were on Descovy.

These promising results bolster the case for lenacapavir as a groundbreaking PrEP option, offering an extended duration of protection and a high efficacy rate. As Gilead prepares for its regulatory submissions, the company is poised to potentially transform the landscape of HIV prevention with lenacapavir, presenting a powerful tool in the global fight against HIV/AIDS.