European CHMP Issues Positive Opinion for Viread(R) for the Treatment of Chronic Hepatitis B

The CHMP's positive opinion will be forwarded to the European Commission, which will amend the Marketing Authorisation for Viread in the 27 countries of the European Union to reflect the Type II variation. The European Commission generally issues an updated Marketing Authorisation within a few months following a positive CHMP recommendation. Viread represents Gilead's second once-daily antiviral developed for the potential treatment of chronic hepatitis B. The active ingredient in Viread, tenofovir disoproxil fumarate, is the most widely prescribed molecule for the treatment of HIV infection in the United States and several countries of the EU.

"The complications associated with chronic hepatitis B make it a leading cause of death worldwide," said Patrick Marcellin, MD, Hopital Beaujon, Clichy, France. "In Europe, the incidence of chronic hepatitis B is significant and growing, which underscores the importance of increased screening and immunization for eligible patients, and the need for safe and effective treatment options that can slow or potentially even halt the progression of liver damage for patients living with chronic hepatitis B."

The application is based primarily on data from two ongoing Phase III clinical trials, Studies 102 and 103, in patients chronically infected with the hepatitis B virus (HBV). These studies evaluate the efficacy, safety and tolerability of Viread compared to adefovir dipivoxil. Positive data from both studies were described in late-breaker presentations at the annual meeting of the American Association for the Study of Liver Diseases in November 2007. Additional 72-week data from these studies will be presented at the annual meeting of the European Association for the Study of the Liver (EASL), taking place in Milan, Italy, April 23-27.

Gilead has also submitted applications for marketing approval of Viread for hepatitis B in the United States, Australia, Canada, New Zealand and Turkey.

About Chronic Hepatitis B

Chronic hepatitis B is a common and potentially fatal liver disease caused by the hepatitis B virus, which is up to 100 times more easily transmitted than HIV. Chronic hepatitis B can produce no symptoms in its earlier stages so many individuals are unaware that they are infected until they have advanced liver disease. Complications commonly associated with chronic hepatitis B include scarring of the liver (cirrhosis), liver failure and liver cancer. More than 400 million people are estimated to be chronically infected with HBV worldwide and, without treatment, up to one quarter of those will ultimately die of liver disease.

About Viread (tenofovir disoproxil fumarate) for HIV

In the United States, Viread is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection.

Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination with other antiretrovirals. Viread is not approved for the treatment of chronic hepatitis B virus (HBV) infection and the safety and efficacy of Viread have not been established in patients coinfected with HBV and HIV. Severe acute exacerbations of hepatitis B have been reported in patients who have discontinued Viread. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in patients who are co-infected with HIV and HBV and discontinue Viread. If appropriate, initiation of anti-hepatitis B treatment may be warranted.

It is important for patients to be aware that anti-HIV medicines including Viread do not cure HIV infection or AIDS, and do not reduce the risk of transmitting HIV to others.

Renal impairment, including cases of acute renal failure and Fanconi syndrome (renal tubular injury with severe hypophosphatemia), has been reported in association with the use of Viread. It is recommended that creatinine clearance be calculated in all patients prior to initiating therapy with Viread and as clinically appropriate during therapy. Routine monitoring of calculated creatinine clearance and serum phosphorous should be performed in patients at risk for renal impairment. Dosing interval adjustment and close monitoring of renal function are recommended in all patients with creatinine clearance less than 50mL/min. Viread should be avoided with concurrent or recent use of a nephrotoxic agent.

The U.S. package insert advises that co-administration of Viread and didanosine should be undertaken with caution. Patients should be monitored closely for didanosine-associated adverse events and didanosine should be discontinued if these occur. Patients on atazanavir and lopinavir/ritonavir plus Viread should be monitored for Viread-associated adverse events and Viread should be discontinued if these occur. When co-administered with Viread, it is recommended that atazanavir be given with ritonavir 100 mg. Atazanavir without ritonavir should not be co-administered with Viread.

Decreases in bone mineral density (BMD) at the lumbar spine and hip have been seen with the use of Viread. The effect on long-term bone health and future fracture risk is unknown. Cases of osteomalacia (associated with proximal renal tubulopathy) have been reported in association with the use of Viread.

Changes in body fat have been observed in patients taking anti-HIV medicines. The mechanism and long-term health effect of these changes are unknown. Immune Reconstitution Syndrome has been reported in patients treated with combination therapy, including Viread.

The most common adverse events among patients receiving Viread with other antiretroviral agents in a pivotal clinical study (Study 903) were mild to moderate gastrointestinal events and dizziness. Moderate to severe adverse events occurring in more than 5 percent of patients receiving Viread included rash (rash, pruritis, maculopapular rash, urticaria, vesiculobullous rash and pustular rash), headache, pain, diarrhea, depression, back pain, fever, nausea, abdominal pain, asthenia (weakness) and anxiety. In another pivotal study (Study 907), less than 1 percent of patients discontinued participation because of gastrointestinal events.

Full prescribing information for Viread in the United States is available at www.Viread.com. For full prescribing information outside of the United States physicians should consult their local product labeling.

The parent compound of Viread was discovered through a collaborative research effort between Dr. Antonin Holy, Institute for Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic (IOCB) in Prague and Dr. Erik DeClercq, Rega Institute for Medical Research, Katholic University in Leuven, Belgium.

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 Australia.

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 risks that regulatory authorities may not approve Viread for the treatment of chronic hepatitis B in the United States or European Union, and marketing approval, if granted, may have 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 Annual Report on Form 10-K for the year ended December 31, 2007, 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.

Viread is a registered trademark of Gilead Sciences, Inc.

For more information on Gilead, please call the Gilead Public Affairs Department at 1-800-GILEAD-5 (1-800-445-3235) or visit www.gilead.com

SOURCE: Gilead Sciences, Inc.

Gilead Sciences, Inc. Susan Hubbard, 650-522-5715 (Investors) Cara Miller, 650-522-1616 (Media) www.gilead.com