Gilead Sciences Receives Marketing Authorization for VISTIDE® in European Union

Pharmacia & Upjohn Has Exclusive Rights in Europe

Foster City, CA -- May 1, 1997

Gilead Sciences, Inc. (NASDAQ:GILD) announced today that it has received marketing authorization for VISTIDE (cidofovir injection) from the European Commission (EC). This authorization allows the product to be marketed in all 15 countries of the European Union as an intravenous treatment for cytomegalovirus (CMV) retinitis in patients with AIDS. CMV retinitis is a rapidly progressing viral infection that may affect a patient's vision over time and may ultimately lead to blindness in patients with late-stage AIDS. The EC's action follows a December 1996 recommendation for approval from the Committee for Proprietary Medicinal Products (CPMP).

Pharmacia & Upjohn (P&U) has exclusive marketing rights for VISTIDE outside the United States. In Europe, an amendment will be filed to transfer the marketing authorization from Gilead to P&U. P&U will then begin making the product available throughout the European Union on a country-by-country basis as pricing and reimbursement negotiations are completed.

VISTIDE - A Potent Option for CMV Retinitis

Results from human clinical studies demonstrate that VISTIDE, a potent systemic therapy, significantly delays the progression of both newly diagnosed and previously treated (relapsing) CMV retinitis in patients with AIDS. VISTIDE is given by intravenous infusion once per week for two weeks (induction) and once every other week thereafter (maintenance). In contrast, other approved intravenous treatments for CMV retinitis are given daily or multiple times each day and often require the use of a surgically implanted catheter in the chest or arm for chronic administration. The dose-limiting side effect of VISTIDE is renal impairment, which can be managed with proper patient selection and adherence to dosing guidelines, including the co-administration of oral probenecid and hydration.

The Gilead / P&U Marketing Agreement

Gilead Sciences developed VISTIDE and currently markets the product independently in the United States for the treatment of CMV retinitis in patients with AIDS. In August 1996, Gilead licensed marketing rights outside the United States to P&U. Under the terms of this agreement, Pharmacia & Upjohn paid Gilead a $10 million up-front licensing fee and will pay Gilead a $10 million milestone fee within 30 days of the EC authorization announced today.

In addition, within 60 days, P&U will purchase 1,133,786 newly issued shares of Gilead Series B Preferred Stock for $40 million, or $35.28 per share, which represents a 45% premium over the average closing price of Gilead's Common Stock for the 30 trading days prior to today's announcement of European Union marketing authorization. These shares will not be publicly registered and will be convertible at P&U's option into shares of Gilead Common Stock on a one-for- one basis.

Gilead Sciences

Gilead Sciences is a biopharmaceutical company dedicated to the development and commercialization of treatments for human diseases. The Company's business and scientific endeavors are focused on making new therapies available to patients, physicians and the healthcare system. Gilead's expertise has resulted in a pipeline of proprietary therapeutics for important viral diseases, and the Company's research programs seek additional treatment options for viral diseases, as well as vascular diseases and cancer. Gilead common stock is traded on The Nasdaq Stock Market under the symbol GILD.

Pharmacia & Upjohn

Pharmacia & Upjohn is a global, innovative-driven pharmaceutical and health care company. Pharmacia & Upjohn's products, services and employees demonstrate its commitment to improve wellness and quality of life for people around the world.

VISTIDE is a registered trademark of Gilead Sciences, Inc.