KENILWORTH, N.J. – Gilead Sciences and Merck today announced that they have entered into an agreement to co-develop and co-commercialize long-acting treatments in HIV that combine Gilead’s investigational capsid inhibitor, lenacapavir, and Merck’s investigational nucleoside reverse transcriptase translocation inhibitor, islatravir, into a two-drug regimen with the potential to provide new, meaningful treatment options for people living with HIV.

Islatravir and lenacapavir are both potentially first-in-class medicines in late-stage clinical trials, with significant clinical data generated to date. Both medicines have long half-lives and have demonstrated activity at low dosages in clinical studies, which support development as an investigational combination regimen with long-acting formulations, both oral and injectable.

The first clinical studies of the oral combination are expected to begin in the second half of 2021. Under the terms of the agreement, Gilead and Merck will work as partners, sharing operational responsibilities, as well as development, commercialization and marketing costs, and any future revenues.

Merck and Gilead seek to build on their legacies of transforming HIV care by focusing on long-acting therapies, which may represent a meaningful innovation in HIV drug development. While daily, single-tablet regimens are available for people living with HIV, options that would allow for less frequent, oral dosing or infrequent injections rather than daily dosing have the potential to addresspreference considerations, as well as issues associated with adherence and privacy.

As the field of HIV treatment evolves, long-acting therapies may provide additional options for people living with HIV and their physicians that will help continue to put the needs of individuals at the center of their own care.

“At Merck, we are resolute in our commitment to advancing the care of people living with HIV as part of our mission to save and improve lives,” said Kenneth C. Frazier, chairman and chief executive officer, Merck. “This collaboration with Gilead brings together two companies dedicated to the fight against HIV to develop potential new long-acting treatment options, and is an important stepforward in our strategy to harness the full potential of islatravir for the treatment of HIV.”

“Through this agreement with Merck, Gilead is reinforcing its long-term role in transforming HIV care,” said Daniel O’Day, chairman and chief executive officer, Gilead Sciences. “Our work in HIV over the past decades has been shaped by listening to people living with HIV and the physicians who treat them. Now we are taking the same approach with long-acting therapies, combining the mostadvanced science from both companies to accelerate progress.”

Lenacapavir and islatravir, alone and in combination, are investigational and not approved anywhere globally. Their safety and efficacy have not yet been established.