FDA Advisory Committee Supports Approval of Gilead’s Sofosbuvir for Chronic Hepatitis C Infection

  FDA Advisory Committee Supports Approval of Gilead’s Sofosbuvir for Chronic
  Hepatitis C Infection

     – Final FDA Decision on Sofosbuvir Anticipated by December 8, 2013 –

Business Wire

FOSTER CITY, Calif. -- October 25, 2013

Gilead Sciences, Inc. (Nasdaq: GILD) today announced that the Antiviral Drugs
Advisory Committee of the U.S. Food and Drug Administration (FDA) has voted
unanimously (15-0) that the available data support approval of the once-daily
nucleotide analogue sofosbuvir in combination with ribavirin for the treatment
of chronic hepatitis C in adult patients with genotype 2 and 3 infection.
Committee members also voted unanimously (15-0) that the available data
support approval of sofosbuvir in combination with pegylated interferon and
ribavirin for the treatment of chronic hepatitis C in treatment-naïve adult
patients with genotype 1 and 4 infection.

The recommendations of the Advisory Committee are not binding, but will be
considered by FDA as the agency completes its review of Gilead’s New Drug
Application (NDA) for sofosbuvir. Gilead submitted the NDA on April 8, 2013
and was granted a priority review. The FDA also granted sofosbuvir a
Breakthrough Therapy designation. The FDA grants Breakthrough Therapy
designation and priority review status to drug candidates that may offer major
advances in treatment over existing options. A target review date of December
8, 2013 has been set under the Prescription Drug User Fee Act (PDUFA).
Applications for marketing approval of sofosbuvir are also pending in the
European Union, Australia, Canada, New Zealand, Switzerland and Turkey.

The sofosbuvir NDA is supported primarily by data from four Phase 3 studies,
NEUTRINO, FISSION, POSITRON and FUSION, in which 12 or 16 weeks of
sofosbuvir-based therapy was found to be superior or non-inferior to currently
available treatment options or historical controls, based on the proportion of
patients who had a sustained virologic response (HCV undetectable) 12 weeks
after completing therapy (SVR12). During the review, data from an additional
Phase 3 study, VALENCE, were filed to the NDA. In this study, patients with
genotype 3 HCV infection were treated with sofosbuvir and ribavirin for 24
weeks. Patients who achieve SVR12 are considered cured of HCV.

About Sofosbuvir

Sofosbuvir is a nucleotide analogue inhibitor of the HCV NS5B polymerase
enzyme, which plays an essential role in HCV replication. Sofosbuvir is a
direct-acting agent, meaning that it interferes directly with the HCV life
cycle by suppressing viral replication. Sofosbuvir is an investigational
product and its safety and efficacy have not 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 and South 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, EMA and
other regulatory agencies may not approve sofosbuvir in the currently
anticipated timelines or at all, and that any marketing approvals, if granted,
may have significant limitations on their use. In addition, future studies of
sofosbuvir, including in combination with other products, may not produce
favorable results. Further, even if approved, Gilead may not be able to
successfully commercialize sofosbuvir, and may make a strategic decision to
discontinue its development if, for example, the market for the product 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 Gilead’s
Quarterly Report on Form 10-Q for the quarter ended June 30, 2013, 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.

 For more information onGilead Sciences, please visit the company’s website
 atwww.gilead.com, follow Gilead on Twitter (@GileadSciences) or call Gilead
             Public Affairs at 1-800-GILEAD-5 or 1-650-574-3000.

Contact:

Gilead Sciences, Inc.
Patrick O’Brien, 650-522-1936 (Investors)
Cara Miller, 650-522-1616 (Media)