Gilead Announces FDA Advisory Committee Supports Use of Viread™ in Treatment-Experienced Patients with HIV Infection

Foster City, CA -- October 3, 2001

Gilead Sciences, Inc. (Nasdaq: GILD) today announced that the U.S. Food and Drug Administration's (FDA) Antiviral Drugs Advisory Committee unanimously supports use of the company's investigational antiviral agent Viread™ (tenofovir disoproxil fumarate) for the treatment of HIV infection in adult patients who have received prior antiretroviral therapy.

Stating that the risk/benefit ratio of Viread was favorable among the patients in the principal clinical studies, the FDA asked committee members to comment on several specific topics regarding the Viread New Drug Application (NDA), including the patient population in which the drug should be indicated, preclinical bone studies, virology analyses and the company's plans for follow-up studies. The FDA will consider the advisory committee's comments and recommendations about these issues as it completes its priority review of the Viread NDA.

Advisory committee members agreed that the Viread NDA provides clear evidence of the drug's anti-HIV activity in treatment-experienced adult patients. The committee members commented that the statistically significant reductions in HIV RNA achieved in two Viread pivotal studies were noteworthy given that the patient population had extensive prior antiretroviral treatment and associated HIV resistance mutations.

Although a formal vote was not taken, the panel discussed the breadth of the treatment indication for Viread. The panel unanimously recommended the use of Viread in treatment-experienced patients. There was a split opinion about the indication including treatment-naive patients since the data in the NDA were from clinical trials conducted predominantly in treatment-experienced patients. Gilead will work closely with the FDA to finalize the product label.

To further demonstrate the efficacy and safety of Viread in a broader patient population, Gilead will complete an ongoing confirmatory 96-week, 601-patient Phase III clinical trial (Study 903) in treatment-naive patients with HIV infection. Gilead anticipates completing analyses of the 48-week primary endpoints of Study 903 in the first half of 2002 and conducting a second confirmatory study focused on treatment-experienced pediatric patients.

"Today marks a significant milestone for Gilead - a milestone that brings us closer to providing this important drug to the many people living with HIV infection in the United States who are in need of a new treatment option," said John C. Martin, Ph.D., President and Chief Executive Officer, Gilead Sciences. "Based on data from our pivotal studies, we believe that Viread has the potential to be an important new option for the treatment of HIV. The committee's positive comments are consistent with the FDA's commitment to make innovative medicines for HIV available as soon as safety and effectiveness have been demonstrated."

About Viread
Viread is dosed as a single tablet taken once daily and works by blocking reverse transcriptase, an enzyme crucial to the replication of HIV. In May 2001, Gilead submitted a New Drug Application for Viread to the FDA and a Marketing Authorisation Application to the European Agency for the Evaluation of Medicinal Products. In August, Gilead submitted an application seeking regulatory approval in Australia. As an investigational compound, Viread has not yet been determined safe or efficacious in humans for its ultimate intended use.

Expanded Access Program
In January 2001, Gilead initiated an expanded access program to provide Viread to people with advanced HIV infection. Nearly 5,000 patients have enrolled in Viread expanded access programs in the United States, Canada, France, Germany, Ireland, Italy, Portugal, Spain and the United Kingdom. For more information or to request registration materials, physicians in the United States and Canada may call 1-800-GILEAD-5 and those within Europe may call 33-1-44-90-34-46.

Gilead Sciences, Inc., headquartered in Foster City, CA, is an independent biopharmaceutical company that seeks to provide accelerated solutions for patients and the people who care for them. Gilead discovers, develops, manufactures and commercializes proprietary therapeutics for challenging infectious diseases (viral, fungal and bacterial infections) and cancer. Gilead maintains research, development or manufacturing facilities in the United States, Europe and Australia.

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 that could cause actual results to differ materially from those referred to in the forward-looking statements. Such risks and uncertainties include the risk that the FDA may not follow the advice of the advisory committee and may refuse to grant regulatory approval for Viread or may grant approval for a more limited indication. The reader is cautioned not to rely on these forward-looking statements. These and other risks are described in detail in the Gilead Annual Report on Form 10-K for the year ended December 31, 2000 and in Gilead's Quarterly Reports on Form 10-Q, all of which are on file 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.