- Gilead said Monday that it has addressed manufacturing and quality control issues related to one of its most closely watched HIV medicines, and is now permitted to resume testing it.
- In December, Gilead disclosed that the Food and Drug Administration had paused 10 studies of the medicine, called lenacapavir, which is being developed in both oral and injectable versions. The hold specifically pertained to the injectable version, with regulators fearing interactions between it and the glass vials in which it was contained could cause tiny glass particles to form in the solution. By March, these fears led the FDA to reject an approval application for lenacapavir.
- Gilead has since devised a plan and generated data on the "storage and compatibility" of its drug with a different kind of vial. According to the company, the FDA reviewed this work and concluded the studies of injectable lenacapavir may continue. Moving forward, Gilead said it will work as quickly as possible with study site investigators to get trials fully running again.
Gilead has long been the dominant player in the market for HIV treatment. Last year, its arsenal of drugs, which includes blockbuster products like Biktarvy, Genvoya and Descovy, brought in more than $16 billion.
But in spite of this leading position, competition from deep-pocketed rivals like GSK, Johnson & Johnson and Merck & Co. has pushed Gilead to innovate. On that front, the company has identified lenacapavir as one of its most valuable assets.
Lenacapavir has a unique way of preventing HIV from replicating. It's also given once every six months, which is less often than currently available options.
In clinical testing, the drug was shown to keep the virus in check in people who had developed resistances to multiple other HIV drugs. A late-stage study that enrolled 72 of these hard-to-treat patients, for example, found that after half a year of treatment, 80% of those who received lenacapavir and an "optimized background therapy" had viral expression low enough to be considered undetectable by laboratory testing.
Gilead believed these results were strong enough to secure approval, and submitted an application to the FDA last June.
But by December, the approval outlook had at least somewhat dimmed due to study halts and the vial issues. When the FDA later turned down lenacapavir, analysts at Baird noted to clients how the verdict was "not entirely surprising," and would likely delay the drug's launch by a year.
Gilead is now using vials made from aluminosilicate glass as opposed to borosilicate, a change that appears to have alleviated the FDA's concerns. Analysts therefore expect the lenacapavir application to be resubmitted and ultimately approved.
While the initial approval, if it comes, would be for heavily pre-treated HIV patients, Gilead is also testing lenacapavir in combination with other therapies in patients whose infections are already suppressed.
Additionally, the company is evaluating its drug's use as a preventive, so-called PrEP treatment. Data from those trials is expected in 2024.
Should lenacapavir be approved in these broader settings, analysts at RBC Capital Markets estimate that peak annual sales of the drug could exceed $4 billion. They argue, too, that various aspects of the drug, such as its ability to work in combination with other therapies and be dosed both orally and via an injection, could make it a "backbone" in Gilead's HIV franchise after key patents protecting some of the company's other medicines expire in 2025.