Gilead and Chiron Corporation Sign Non-Exclusive HCV Licensing Agreement; Gilead to Initiate Research Programs in Hepatitis C

FOSTER CITY, Calif.--(BUSINESS WIRE)--Aug. 4, 2003--Gilead Sciences, Inc. (Nasdaq:GILD) announced today that it has entered into a non-exclusive licensing agreement with Chiron Corporation for the research, development and commercialization of small molecule therapeutics against selected hepatitis C virus (HCV) drug targets. Under the agreement, Gilead will receive non-exclusive rights to Chiron's HCV technology for drug screening purposes. The financial terms and other details of the agreement were not disclosed.

"Hepatitis C is a therapeutic area with significant unmet medical needs," said John C. Martin, PhD, President and CEO, Gilead Sciences. "We are initiating a significant research and discovery effort to identify and develop potential HCV therapies, leveraging our proven capabilities in antiviral drug development."

Hepatitis C is a viral liver disease, caused by infection with the hepatitis C virus. Globally, more than 170 million people have chronic hepatitis C. Hepatitis C is one of the primary causes of liver failure and transplantation in the United States. Currently, there is no vaccine that can protect against hepatitis C infection.

About Gilead

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes therapeutics to advance the care of patients suffering from life-threatening diseases worldwide. The company has seven marketed products and focuses its research and clinical programs on anti-infectives. Headquartered in Foster City, CA, Gilead has operations 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. 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 the Gilead Annual Report on Form 10-K for the year ended December 31, 2002 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.

For more information on Gilead Sciences, please visit the company's web site at www.gilead.com or call Gilead Public Affairs at 1-800-GILEAD-5 or 1-650-574-3000.


    CONTACT: Gilead Sciences, Inc. Susan Hubbard, 650/522-5715 (Investors)
             Erin Edgley, 650-522-5635 (Media)

    SOURCE: Gilead Sciences, Inc.