FOSTER CITY, Calif.--(BUSINESS WIRE)--Jun. 28, 2012--
      Gilead Sciences, Inc. (Nasdaq: GILD) announced today it has submitted a
      New Drug Application (NDA) to the U.S. Food and Drug Administration
      (FDA) for marketing approval of cobicistat, a pharmacoenhancing or
      “boosting” agent that increases blood levels of certain commercially
      available protease inhibitors, including atazanavir and darunavir, in
      order to enable once-daily dosing. Cobicistat is also a component of the
      Quad once-daily single tablet regimen for HIV, which is currently under
      U.S. and European regulatory review for treatment-naïve adult patients.
    
      “With today’s filing, Gilead’s series of U.S. and European regulatory
      filings for the Quad and its investigational components is complete,”
      said Norbert Bischofberger, PhD, Executive Vice President, Research and
      Development and Chief Scientific Officer, Gilead Sciences. “We will
      continue to work with regulatory authorities to bring these important
      new therapies to people living with HIV.”
    
      The NDA for cobicistat is supported by 48-week data from a pivotal Phase
      3 study (Study 114) in which cobicistat met its primary objective of
      non-inferiority to ritonavir when both agents were administered with a
      background regimen of atazanavir sulfate plus Truvada®
      (emtricitabine and tenofovir disoproxil fumarate). The NDA is also
      supported by pharmacokinetic data demonstrating that cobicistat boosts
      blood levels of atazanavir and darunavir similar to ritonavir.
    
      Gilead entered into an agreement with Janssen R&D Ireland in June 2011
      for the development of a fixed-dose combination of cobicistat and
      darunavir. In October 2011, Gilead announced an agreement with
      Bristol-Myers Squibb to develop a fixed-dose combination of cobicistat
      and atazanavir. Subject to regulatory approval, Janssen and
      Bristol-Myers Squibb will be responsible for the formulation,
      manufacturing, registration, distribution and worldwide
      commercialization of the cobicistat and darunavir fixed-dose combination
      and the cobicistat and atazanavir fixed-dose combination, respectively.
    
About Cobicistat
      Cobicistat is Gilead’s proprietary potent mechanism-based inhibitor of
      cytochrome P450 3A (CYP3A), an enzyme that metabolizes drugs in the
      body. Unlike ritonavir, cobicistat acts only as a pharmacoenhancer and
      has no antiviral activity.
    
About the Quad
      The Quad contains four Gilead compounds in a complete once-daily, single
      tablet regimen: elvitegravir 150 mg, an integrase inhibitor; cobicistat
      150 mg, a “boosting” agent that enables elvitegravir once-daily dosing;
      and Truvada (emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg).
    
      Cobicistat, elvitegravir and the Quad are investigational products and
      their safety and efficacy have not yet been established.
    
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.
    
Forward-Looking Statement
      This press release includes forward-looking statements, within the
      meaning of the Private Securities Litigation Reform Act of 1995, that
      are subject to risks, uncertainties and other factors, including the
      risk that FDA and other regulatory agencies may not approve cobicistat
      or any co-formulations containing cobicistat, or the Quad, and that any
      marketing approvals, if granted, may have significant limitations on
      their use. Further, even if approved, Gilead may not be able to
      successfully commercialize these products, and may make a strategic
      decision to discontinue their development if, for example, the market
      for the products fails to materialize as expected. These risks,
      uncertainties and other factors could cause actual results to differ
      materially from those referred to in the forward-looking statements. The
      reader is cautioned not to rely on these forward-looking statements.
      These and other risks are described in detail in Gilead’s Quarterly
      Report on Form 10-Q for the quarter ended March 31, 2012, as filed with
      the U.S. Securities and Exchange Commission. All forward-looking
      statements are based on information currently available to Gilead, and
      Gilead assumes no obligation to update any such forward-looking
      statements.
    
U.S. full prescribing information for Truvada is available at www.Truvada.com.
    
Truvada is a registered trademark of Gilead Sciences, Inc.
For more information on Gilead Sciences, please visit the company’s
      website at www.gilead.com,
      follow Gilead on Twitter (@GileadSciences)
      or call Gilead Public Affairs at 1-800-GILEAD-5 or 1-650-574-3000.
Source: Gilead Sciences, Inc.
      Gilead Sciences, Inc.Patrick O’Brien, 650-522-1936 (Investors)Erin
      Rau, 650-522-5635 (Media)