Gilead Submits New Drug Application to U.S. FDA for Sofosbuvir for the Treatment of Hepatitis C

  Gilead Submits New Drug Application to U.S. FDA for Sofosbuvir for the
  Treatment of Hepatitis C

 -- Sofosbuvir Would Form Basis of First All-Oral Regimen for HCV Genotype 2
  and 3 Patients, and Interferon-Sparing Regimen for Genotype 1 Patients --

Business Wire

FOSTER CITY, Calif. -- April 08, 2013

Gilead Sciences (Nasdaq: GILD) today announced that the company has submitted
a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA)
for approval of sofosbuvir, a once-daily oral nucleotide analogue for the
treatment of chronic hepatitis C virus (HCV) infection. The data submitted in
this NDA support the use of sofosbuvir and ribavirin (RBV) as an all-oral
therapy for patients with genotype 2 and 3 HCV infection, and for sofosbuvir
in combination with RBV and pegylated interferon (peg-IFN) for treatment-naïve
patients with genotype 1, 4, 5 and 6 HCV infection.

Chronic HCV infection affects up to four million Americans, particularly
individuals born between 1946 and 1964. The disease is the leading cause of
liver cancer and liver transplantation in the United States. Treatment for HCV
currently includes 24-48 weeks of therapy with peg-IFN, which has to be
injected and is associated with significant side effects, leaving some
patients unable to complete therapy. If approved, sofosbuvir would shorten HCV
therapy to 12 to 16 weeks, and depending on the genotype, would either
eliminate or reduce the duration of peg-IFN injections.

“Current therapies are not suitable for large numbers of patients with HCV
infection, and are challenging to take and tolerate,” said John C. Martin,
PhD, Chairman and Chief Executive Officer of Gilead Sciences. “Sofosbuvir’s
antiviral potency, safety profile and once-daily administration have the
potential to improve cure rates by simplifying and shortening therapy for
patients with this disease.”

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). Patients who achieve SVR12 are considered
cured of HCV.

Gilead plans to file for regulatory approval of sofosbuvir in other
geographies, including the European Union, in the second quarter of 2013. The
European Medicines Agency (EMA) has accepted Gilead’s request for accelerated
assessment for sofosbuvir, a designation that is granted to new medicines of
major public health interest. Accelerated assessment could shorten the EMA’s
review time of sofosbuvir by two months. Granting of accelerated assessment
does not guarantee a positive opinion from the CHMP or approval by the
European Commission.

About Sofosbuvir

Sofosbuvir is a nucleotide analogue inhibitor of the HCV NS5B protein, which
plays an essential role in HCV replication. Unlike ribavirin and pegylated
interferon, sofosbuvir is a direct-acting agent, meaning that it interferes
directly with the HCV life cycle by suppressing viral replication. Sofosbuvir
is intended to become a cornerstone of interferon-free, all-oral treatment
regimens for HCV that achieve higher cure rates more rapidly and with fewer
side effects than current therapeutic options. Sofosbuvir is an
investigational product and its safety and efficacy has 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, EMA and
other regulatory agencies may not approve sofosbuvir, and that any marketing
approvals, if granted, may have significant limitations on their use. In
addition, additional 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 detail in Gilead’s Annual Report on Form 10-K for
the year ended December 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.

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.

Contact:

Gilead Sciences
Patrick O’Brien, 650-522-1936 (Investors)
Nathan Kaiser, 650-522-1853 (Media)