FDA Grants Approval for HIV Treatment to Fight Drug Resistance

Last week, the FDA approved Gilead Science’s Sunlenca (lenacapavir), the first and only capsid inhibitor-based HIV treatment. The treatment is intended for adult patients whose HIV cannot be treated with other available drugs because of resistance, tolerance, or safety considerations.

Sunlenca was tested in the Phase 2 CAPELLA study that included 36 participants with drug-resistant HIV-1 and a detectable viral load. The drug was administered every six months in combination with the patients’ failing antiretroviral regimen. After a year of therapy, 83% of patients in the test arm of the study achieved an undetectable viral load. Researchers conducting the Phase 2 study also found no serious adverse events associated with the trial.

The Sunlenca regimen is delivered by an initial loading phase where patients are administered oral tablets of the drug, followed by a maintenance dose of subcutaneous injections every six months. Currently, it is the only HIV treatment administered twice yearly.

“An effective antiretroviral regimen can be devised for most people living with the virus; however, some people living with HIV no longer have durable viral suppression due to resistance to multiple classes of antiretroviral therapies,” said Sorana Segal-Maurer, MD, Director of the Dr. James J. Rahal Jr. Division of Infectious Diseases at New York-Presbyterian Queens, and the Site Principal Investigator for the CAPELLA trial. “Following today’s decision from the FDA, lenacapavir helps to fill a critical unmet need for people with complex prior treatment histories and offers physicians a long-awaited twice-yearly option for these patients who otherwise have limited therapy choices."

In December of 2021, the FDA placed a clinical hold on Sunlenca due to chemistry, manufacturing, and control issues. Experts at the agency rejected the borosilicate glass vials used to store the solution and encouraged Gilead to change the type of glass they were using. Eventually, the FDA lifted the clinical hold after Gilead found an alternative glass type compatible with the Sunlenca injectable solution.

Drug-resistant HIV infections that Sunlenca would treat occur when the HIV virus mutates and reduces the effectiveness of medications. Drug-resistant HIV can also spread from person to person via traditional forms of transmission. Currently, up to 10% of patients with HIV develop drug resistance to at least one class of drug, and the level of drug-resistant HIV infections has slowly increased over time.

Capsid inhibitors present a new class of treatment options that interferes with the HIV virus’ outer shell, disrupting multiple stages of the HIV life cycle. Most currently approved antiretroviral drugs do not target the HIV capsid. In addition to Sunlenca, The FDA has already approved or tentatively approved over 200 anti-retroviral therapies to treat HIV worldwide.

*This article was corrected on 1-3-2023 to reflect correct dosing information and the date of an FDA clinical hold*