Bristol-Myers Squibb is combining its protease inhibitor Reyataz (atazanavir sulfate) with a pharmacoenhancing agent from Gilead Sciences Inc. called cobicistat that can increase blood levels of HIV medicines to possibly allow for one-pill, once-daily dosing.

Phase 2 and 3 trials for atazanavir and cobicistat are being studied by Gilead in HIV-1 treatment-naïve patients.

Eliott Sigal, M.D., Ph.D., Executive Vice President, Chief Scientific Officer, & President of R&D for Bristol-Myers Squibb, says, “This collaboration with Gilead builds on Bristol-Myers Squibb’s longstanding commitment to develop medicines that have the potential to provide meaningful benefit to HIV patients, specifically aiming to enhance treatment options.A REYATAZ and cobicistat fixed-dose combination has the potential not only to help simplify HIV therapy but also to address an unmet medical need in HIV for additional, innovative treatment options.”

The medication Reyataz is typically used with other medicines that treat HIV-positive people 6 years of age or older.

Bristol-Myers Squibb plans to manufacture, develop, register, formulate, distribute, and commercialize Reyataz and cobicistat fixed-dose combinations worldwide, while paying Gilead an undisclosed royalty based on sales.

Only Gilead will possess the rights for the manufacture, development, and commercialization of cobicistat as a stand-aolone product.

Cobicistat is a mechanism-based inhibiter of cytochrome P450 3A (CYP3A), an enzyme that is able to metabolize drugs in the body. Cobicistat has not yet been determined safe or effective in humans, given that it is still considered an investigational product.

Norbert Bischofberger, Ph.D., Executive Vice President of R&D, and Chief Scientific Officer for Gilead Sciences explains how cobicistat, “provides us with the potential to co-formulate with a variety of commercially available HIV medicines that require boosting for optimal efficacy, such as the protease inhibitor atazanavir. This agreement represents a shared commitment between Gilead and Bristol-Myers Squibb to develop multiple treatment options that can address individual patient needs.”