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Gilead and Tibotec To Develop New Combo Pill

Gilead Sciences and Tibotec Pharmaceuticals announced a collaboration to develop a fixed-dose combination pill containing the protease inhibitor darunavir (Prezista) plus the novel boosting agent cobicistat.

Cobicistat is an experimental booster, or pharmacoenhancer, that does not have anti-HIV activity itself. Cobicistat is also included in the investigational single-tablet regimen "Quad" pill containing elvitegravir (a new integrase inhibitor) plus tenofovir/emtricitabine (the drugs in Truvada).

Below is an edited excerpt from a press release issued last week by Gilead; the full release is available online at http://investors.gilead.com. Tibotec issued a similar announcement the same day, available at http://www.investor.jnj.com.

Gilead Sciences Announces Agreement With
Tibotec Pharmaceuticals to Develop and Commercialize
a New Fixed-Dose Combination of Cobicistat and Prezista

Foster City, CA -- June 28, 2011 -- Gilead Sciences, Inc. (Nasdaq:GILD) today announced that it has entered into a license agreement with Tibotec Pharmaceuticals for the development and commercialization of a new fixed-dose antiretroviral combination product containing Gilead's cobicistat and Tibotec's protease inhibitor Prezista (darunavir). Cobicistat is an investigational pharmacoenhancing or "boosting" agent that increases blood levels of certain HIV medicines to allow for once-daily dosing. Prezista is indicated in the United States for the treatment of HIV-infected individuals and is co-administered with ritonavir in combination with other antiretroviral agents.

"Cobicistat's formulation and clinical profile provides us with the flexibility to co-formulate and develop new combination products, including the potential to co-formulate with protease inhibitors such as Prezista," said Norbert W. Bischofberger, PhD, Gilead's Executive Vice President, Research and Development and Chief Scientific Officer. "This agreement represents another important step forward in our commitment to developing simplified treatment regimens that can help address the individual needs of people living with HIV."

Subject to regulatory approval, Tibotec will be responsible for the formulation, manufacturing, registration, distribution and commercialization of the cobicistat and Prezista fixed-dose combination worldwide. Gilead retains sole rights for the manufacture, development and commercialization of cobicistat as a stand-alone product and for use in combination with other agents.

In connection with this agreement, the companies are also negotiating terms for the development and commercialization of a future single-tablet regimen (STR) combining Prezista with Gilead's Emtriva (emtricitabine), which is approved for the treatment of HIV infection on a worldwide basis, and its investigational agents GS 7340 and cobicistat. Gilead would be responsible for the development and commercialization of the new STR on a worldwide basis. The agreement to develop the fixed-dose combination of cobicistat and Prezista iscontingent uponthe signing of the agreement to develop the Emtriva, GS 7340, cobicistat and Prezista STR.

About Cobicistat

Gilead is evaluating cobicistat in a pivotal Phase III program, both as a stand-alone boosting agent for protease inhibitors, in this case with once-daily atazanavir, as well as part of the all Gilead investigational fixed-dose single-tablet "Quad" regimen of elvitegravir, cobicistat and Truvada (emtricitabine/tenofovir disoproxil fumarate) for the treatment of HIV infection.

Cobicistat is Gilead's proprietary potent mechanism-based inhibitor of cytochrome P450 3A (CYP3A), an enzyme that metabolizes drugs in the body.

About GS 7340

GS 7340, Gilead's investigational anti-HIV agent in Phase Ib studies, is a prodrug of tenofovir, the active agent in the company's HIV drug Viread (tenofovir disoproxil fumarate). A GS 7340/Emtriva tablet has been developed and entered a human bioavailability study earlier this year.

Cobicistat and GS 7340 are investigational products and have not yet been determined safe or efficacious in humans.

About Gilead Sciences

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company's mission is to advance the care of patients suffering from life-threatening diseases worldwide. Headquartered in Foster City, California, Gilead has operations in North America, Europe and Asia Pacific.

7/5/11

Sources

Gilead Sciences. Gilead Sciences Announces Agreement With Tibotec Pharmaceuticals to Develop and Commercialize a New Fixed-Dose Combination of Cobicistat and Prezista. Press release. June 28, 2011.

Tibotec Pharmaceuticals. Tibotec Pharmaceuticals announces agreement with Gilead Sciences to Develop and Commercialize a New Fixed-Dose Combination of Prezista and Cobicistat. Press release. June 28, 2011.