Biannual Gilead HIV drug shots effective in major prevention study

Gilead Sciences has announced that its HIV drug, lenacapavir, demonstrated such high efficacy in preventing infections during a significant late-stage clinical trial that monitors recommended halting the trial early. The study, known as Purpose 1, was conducted in South Africa and Uganda and included cisgender women as participants. Lenacapavir's performance was compared to once-daily Truvada and the general HIV infection rates among the population. Remarkably, no HIV infections were reported in the group receiving lenacapavir, indicating its superior effectiveness.

Gilead aims to establish lenacapavir as a viable and more convenient preventive option for individuals at risk of HIV infection by offering it as a twice-yearly injection. The company anticipates receiving additional data from another study by the end of this year or early next year. This upcoming study focuses on cisgender men who have sex with men, as well as certain transgender and gender non-binary individuals.

In recent years, Gilead has heavily invested in oncology, spending tens of billions on acquiring cancer drugs and their developers. Nevertheless, HIV remains a core area for the company, with a range of approved pills designed to prevent or treat infections. Lenacapavir, being an injection administered twice a year, could present a more user-friendly preventive measure against HIV.

Linda-Gail Bekker, director of the Desmond Tutu HIV Center at the University of Cape Town, emphasized the potential benefits of lenacapavir for pre-exposure prophylaxis (PrEP). She highlighted that although traditional HIV prevention methods are effective when used as prescribed, twice-yearly lenacapavir could mitigate the stigma and discrimination associated with taking or storing oral PrEP pills. Additionally, the biannual dosing schedule might improve adherence and persistence in PrEP usage.

Gilead shared limited results from the Purpose 1 trial, with detailed information to be disclosed at a forthcoming medical conference. The study involved over 5,300 women and adolescent girls, who were randomized to receive either preventive lenacapavir, once-daily oral Descovy, or once-daily oral Truvada. Both Descovy and Truvada are already approved PrEP options. Lenacapavir and Descovy were compared against Truvada and background HIV rates, as using a placebo in HIV prevention studies is now deemed unethical. Researchers noted zero HIV infections in the lenacapavir group, compared to a background incidence rate of 2.41 per 100 person-years.

While lenacapavir outperformed once-daily Truvada, Gilead did not disclose the specific incidence rate for the Truvada group. HIV incidence in the once-daily Descovy group was similar to that in the Truvada group but did not meet the statistical threshold to demonstrate superiority over background HIV rates. Gilead attributed this finding to potential adherence issues with daily pills.

Brian Abrahams, an analyst at RBC Capital Markets, described the study results as nearly ideal. Although positive outcomes were anticipated, some uncertainty existed because Gilead had not conducted a mid-stage study beforehand. To support an approval application for lenacapavir's use in HIV prevention, Gilead needs positive results from the ongoing Purpose 2 study. Currently, lenacapavir is approved in the U.S. and Europe as Sunlenca for treating resistant HIV infections in cases where other therapies are ineffective.

Gilead has promised to provide more information soon on its efforts to support access to lenacapavir, particularly in countries with high infection rates but limited resources, if the drug is approved for PrEP.