2000 First Quarter Highlights

Foster City, CA -- April 27, 2000

Gilead Sciences is an independent biopharmaceutical company that seeks to provide accelerated solutions for patients and the people who care for them. During the first quarter of 2000, the Company received product and royalty revenue from the sale of AmBisome® (liposomal amphotericin B) for the treatment of severe fungal infections, Tamiflu™ (oseltamivir phosphate) for the treatment of influenza A and B in adults, DaunoXome® (daunorubicin citrate liposome injection) for AIDS-related Kaposi’s Sarcoma and VISTIDE® (cidofovir injection) for the treatment of CMV retinitis, as well as from collaborative agreements with its pharmaceutical partners.

• Gilead and Virco Collaborate to Promote HIV Resistance Services – In March, Gilead and Virco announced a collaboration to promote Virco’s HIV resistance services designed to characterize the susceptibility of the human immunodeficiency virus (HIV) to available drugs. Under the terms of this fee-for-service agreement, effective April 1, 2000, the Gilead sales force is responsible for promoting the Virco portfolio of phenotypic and genotypic tests and interpretive services to HIV-treating physicians in the United States.

• Exclusive License Agreement for NX 1838 Announced – In April, Gilead and EyeTech Pharmaceuticals announced an exclusive, worldwide licensing agreement for NX 1838, Gilead’s proprietary aptamer for the potential treatment of age-related macular degeneration. Under this agreement, EyeTech has paid Gilead an up-front licensing fee of $7 million, and Gilead will receive additional cash payments of up to $25 million upon achievement of certain development milestones, as well as royalties on product sales. EyeTech has also issued Gilead a warrant to purchase 833,333 shares of EyeTech Series B Convertible Preferred Stock, exercisable over a five year period at a per share price of $6.00, the price paid by the investors participating in EyeTech’s recent round of venture capital financing.

• New AmBisome Label Includes Superior Safety Data – In February, Fujisawa Healthcare, Inc., Gilead’s North American marketing partner, received approval from the U.S. FDA for a supplemental new drug application to expand the package insert for AmBisome. The new label now includes comparative data from a multi-center, randomized, double-blind trial where AmBisome was demonstrated to be significantly safer than Abelcet® (amphotericin B lipid complex) in the management of potentially life threatening fungal infections in febrile neutropenic cancer patients.

• AmBisome Receives Approvals in Canada, Norway and New Indication in Sweden, Turkey – In March, Fujisawa received marketing approval from Health Canada for AmBisome for the treatment of systemic or disseminated infections due to Candida, Aspergillus or Cryptococcus in patients who are refractory to or intolerant of conventional amphotericin B therapy, or have renal impairment. Fujisawa Canada will market AmBisome exclusively in Canada. AmBisome also received marketing approval in Norway and approval for the Fever of Unknown Origin indication in Sweden and Turkey.

• Data Describing Adefovir Dipivoxil Activity Against Lamivudine-Resistant HBV Presented – In April, at the 10th International Symposium on Viral Hepatitis and Liver Disease in Atlanta, Marion Peters, MD, Professor of Medicine and Chief of Hepatology Research at the University of California, San Francisco Medical Center presented clinical data from an open-label study evaluating adefovir dipivoxil in 23 patients with chronic hepatitis B (HBV) infection who have failed treatment with the antiviral agent lamivudine (3TC) due to viral resistance. The data suggest that treatment with adefovir dipivoxil was associated with suppression of HBV DNA to undetectable levels in 80 percent of patients who had 12 to 15 months of treatment. Serious drug-related side effects were not observed, and no patient discontinued therapy due to drug-related side effects.

• Positive Preliminary Tenofovir DF 48-Week Data Released – In April, at the 13^th International Conference on Antiviral Research, Melanie Thompson, MD, Director of the AIDS Research Consortium of Atlanta, presented preliminary 48-week results from a Phase II dose-ranging clinical trial (Study 902) evaluating the safety and efficacy of once-daily tenofovir disoproxil fumarate (tenofovir DF) when used to intensify a stable background antiretroviral regimen in 189 treatment-experienced HIV patients. Treatment with the highest dose of tenofovir DF (300 mg) in 41 antiretroviral-experienced patients was associated with a mean change from baseline in HIV RNA of 0.68 log₁₀ copies/mL at 48 weeks. The discontinuation rate and incidence of adverse events were similar across all arms of the study, including placebo. Additionally, through 48 weeks, no patients randomized to tenofovir DF 300 mg had confirmed elevations (>0.5 mg/dL) of serum creatinine (a marker of kidney function).

• Upcoming Milestones

SAFE HARBOR DISCLAIMER: The Upcoming Milestones listed above contain “forward-looking” information (within the meaning of the Private Securities Litigation Reform Act of 1995) that involves substantial risk and uncertainty. Actual results may differ materially based on a variety of factors, particularly those relating to the development, approval and marketing of pharmaceutical products as described in the “Risk Factors” section of Gilead’s SEC reports, including the report on Form 10-K for the year ended December 31, 1999.