Gilead’s Sofosbuvir for Hepatitis C Meets Primary Endpoint in Fourth Pivotal Phase 3 Study

  Gilead’s Sofosbuvir for Hepatitis C Meets Primary Endpoint in Fourth Pivotal
  Phase 3 Study

             -- Initial Regulatory Filings Planned for Q2 2013 --

Business Wire

FOSTER CITY, Calif. -- February 19, 2013

Gilead Sciences (Nasdaq:GILD) today announced topline results from the Phase 3
FUSION study evaluating 12- and 16-week courses of therapy with the once-daily
nucleotide sofosbuvir plus ribavirin (RBV) in treatment-experienced patients
with genotype 2 or 3 chronic hepatitis C virus (HCV) infection who failed
prior treatment. The study met its primary efficacy endpoint of superiority
compared to a predefined historic control sustained virologic response (SVR)
rate of 25 percent. In FUSION, 50 percent of patients (n=50/100) in the
12-week arm and 73 percent of patients (n=69/95) in the 16-week arm achieved
SVR12 (p<0.001 for both arms).

“This study demonstrates that all-oral therapy with sofosbuvir provides
significant efficacy among difficult-to-treat hepatitis C patients who could
not be cured by prior regimens containing pegylated interferon and now have
limited treatment options,” said Norbert Bischofberger, PhD, Executive Vice
President of Research and Development and Chief Scientific Officer. “With
positive results from all four Phase 3 trials now in hand, Gilead is on track
to meet its goal of filing regulatory applications in the United States and
Europe in the second quarter.”

In the FUSION study, HCV genotype 2 or 3 patients who failed prior
interferon-based therapy were randomized (1:1) to receive either a 12-week
(n=103) or 16-week (n=98) course of sofosbuvir 400 mg once daily plus RBV
(1,000 or 1,200 mg/day). Sixty-three percent of patients were infected with
genotype 3. In the 12-week arm, SVR12 rates were 86 percent among genotype 2
and 30 percent among genotype 3 patients. In the 16-week arm, SVR12 rates were
94 percent among genotype 2 and 62 percent among genotype 3 patients. Among
the 34 percent of FUSION participants who had compensated cirrhosis at
baseline, 31 percent achieved SVR12 in the 12-week arm, and 66 percent
achieved SVR12 in the 16-week arm. All patients in the study became HCV
negative on treatment, and relapse accounted for all virologic failures.

No patients discontinued sofosbuvir or RBV due to adverse events. The most
common adverse events reported in ≥15 percent of patients in the study were
fatigue, headache, insomnia and nausea.

Results from all four pivotal Phase 3 studies of sofosbuvir – FUSION,
POSITRON, FISSION and NEUTRINO – will support the initial regulatory filing
for sofosbuvir as part of all-oral therapy with RBV among genotype 2 and 3
treatment-naïve, treatment-experienced and interferon-intolerant HCV patients,
and for sofosbuvir in combination with RBV and pegylated interferon among
treatment-naïve patients with genotypes 1, 4, 5 and 6.

Full results from these studies will be presented at a future scientific
conference. Additional information about these and other ongoing clinical
studies of sofosbuvir can be found at Sofosbuvir is an
investigational product and its safety and efficacy have not yet been

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 possibility that the
proportion of patients who maintain a sustained virologic response with longer
follow up will not be as favorable as the sustained virologic response rates
reported in this press release, and the possibility of unfavorable results
from other clinical trials involving sofosbuvir. As a result, sofosbuvir may
never be successfully commercialized. In addition, Gilead may make a strategic
decision to discontinue development of the compound if, for example, Gilead
believes commercialization will be difficult relative to other opportunities
in its pipeline. Further, Gilead may be unable to file for regulatory approval
of sofosbuvir in the currently anticipated timelines or at all. If marketing
approval is granted for this product, there may be significant limitations on
its use. 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 September 30, 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, follow Gilead on Twitter (@GileadSciences) or call Gilead
             Public Affairs at 1-800-GILEAD-5 or 1-650-574-3000.


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