The drug appeared to be safe. It also appears likely to be effective. These individuals weren’t at risk of HIV. But the levels of the drug in their blood plasma remained high, even in the people who got the lower dose.
A year after their injection, the levels of the drug were still higher than those seen in people who were protected from HIV in last year’s trials. This suggests the new annual shot will be just as protective as the twice-yearly shot, says Renu Singh, a senior director in clinical pharmacology at Gilead Sciences, who presented the findings at the Conference on Retroviruses and Opportunistic Infections in San Francisco.
“I was just so excited [to hear the results],” says Carina Marquez, an associate professor of medicine at the University of California, San Francisco, who both studies infectious disease and treats people with HIV.
Annual shots would make things easier—and potentially cheaper—for both patients and health-care providers, says Marquez. “It will be a game changer if it works, which looks promising from the phase I data,” she says.
The drug works by interfering with the virus’s ability to replicate. But it also seems to have some very unusual properties, says Singh. It can be taken daily or yearly. Small doses can stay in the blood for days rather than hours. And bigger doses form what’s known as a depot, which gradually releases the drug over time.
“I previously worked at the FDA, and looked at many, many different molecules and products, but I’ve never seen [anything] like this,” Singh adds. She and her colleagues have come up with nicknames for the drug, including “magical,” “the unicorn,” and “limitless len.”
Once a phase I trial is successfully completed, researchers will typically move on to a phase II trial, which is designed to test the efficacy of a drug. That’s not necessary for lenacapavir, given the unprecedented success of last year’s trials. The team at Gilead is currently planning a phase III trial, which will involve testing annual shots in large numbers of people at risk of HIV infection.
The drug isn’t approved yet, but the researchers at Gilead have submitted twice-yearly lenacapavir for approval by the FDA and the European Medicines Agency and hope to have it approved by the FDA in June, says Das. The drug is also being assessed under the EU-Medicines for all (EU-M4all) procedure, which is a collaboration between the EMA and the World Health Organizations to fast-track the approval of drugs for countries outside Europe.
