FDA Grants Marketing Clearance of Gilead's VISTIDE® for the Treatment of CMV Retinitis in Patients with AIDS

VISTIDE Marks Gilead's First Commercial Product

Foster City, CA -- June 27, 1996

Gilead Sciences Inc. (NASDAQ:GILD) today announced that the U.S. Food and Drug Administration (FDA) granted marketing clearance of VISTIDE (cidofovir injection) for the treatment of cytomegalovirus (CMV) retinitis in patients with AIDS. CMV retinitis is a sight-threatening viral infection that progresses rapidly and may lead to blindness.

Gilead shipped VISTIDE within hours of approval to wholesaler and specialty distributors nationwide. The Company will independently market VISTIDE in the United States with an antiviral specialty sales force.

"Patients with AIDS are terrified of the possibility of going blind from CMV retinitis. With VISTIDE, we now have a new treatment that fights CMV retinitis without requiring daily infusions," said Baruch D. Kuppermann, M.D., Ph.D., of the University of California, Irvine, Department of Ophthalmology and a clinical investigator in human studies of VISTIDE.

VISTIDE is infused once per week for two weeks (induction) and then once every other week thereafter (maintenance). Because of the infrequent dosing schedule, a surgically implanted catheter is not required for VISTIDE drug delivery. In contrast, previously approved intravenous agents are given daily or multiple times each day and often require a chronic catheter surgically implanted in the chest or arm for administration. Catheters are a potential source of life-threatening infection, especially in HIV-infected patients with compromised immune systems.

"VISTIDE is a new weapon in the battle against CMV retinitis that offers patients freedom from daily intravenous infusions," said Dr. Jacob Lalezari, co-director of HIV Clinical Research at the Mt. Zion Medical Center, University of California-San Francisco and a clinical investigator in VISTIDE studies.

FDA clearance followed a unanimous recommendation from an advisory committee on March 15 and was based upon data from two pivotal studies demonstrating that VISTIDE delays the time to progression of CMV retinitis. These studies were conducted in patients with CMV retinitis and AIDS. One study enrolled newly diagnosed patients who had not received prior CMV treatment and the other study enrolled patients with relapsing disease that had progressed despite extensive treatments with other intravenous therapies for CMV retinitis.

A third clinical study of VISTIDE is being conducted by an independent NIH-sponsored research group, the Studies of the Ocular Complications of AIDS (SOCA). In March 1996, enrollment of new patients in this study was stopped based upon an interim analysis of safety and efficacy data suggesting VISTIDE delayed the time to progression of CMV retinitis.

In addition, a Treatment IND expanded access program began in September 1995 and has provided VISTIDE free of charge to approximately 450 patients with relapsing CMV retinitis while the marketing application of VISTIDE was pending. The New Drug Application was submitted in October 1995.

The major toxicity of VISTIDE is renal impairment. The potential for nephrotoxicity can be minimized with the administration of probenecid tablets and hydration on the day of each VISTIDE infusion. In addition, laboratory measurements of a patient's urine protein and serum creatinine, a blood marker of kidney function, are monitored before each dose of VISTIDE. Proper use of these tests can guide physicians to adjust the VISTIDE dosage and minimize the potential for toxicity.

"VISTIDE, our first commercial product, represents a key milestone for Gilead and the first of a new class of antiviral therapeutics," said John C. Martin, Ph.D., Gilead's President and Chief Executive Officer. "We are pleased to have worked diligently with the FDA to make VISTIDE available approximately four years after we began human testing."

Gilead will sell VISTIDE in the United States for a catalog price of $589, which represents the approximate drug costs of a two-week course of maintenance treatment or a one-week course of induction therapy. Since VISTIDE is administered only once per week for the first two weeks (induction) and once every other week thereafter (maintenance), costs associated with the implantation and maintenance of a chronic catheter are not required for VISTIDE administration.

Recognizing the importance for patients with AIDS to obtain access to treatment with VISTIDE, Gilead has established a confidential Support Services Program that will assist all patients seeking reimbursement or financial assistance. Patients interested in these services or more information about VISTIDE may call 1-800-Gilead 5 (1-800-445-3235).

Gilead is also pursuing approval of VISTIDE for the treatment of CMV retinitis through a Market Authorisation Application submitted under the European Community's centralized procedure in December 1995. In cooperation with government authorities, Gilead began making VISTIDE available free of charge in France in March 1996 through an expanded access program for patients with relapsing CMV retinitis.

CMV retinitis affects between 15 and 40 percent of patients with AIDS and is caused by viral infection of the retina. CMV retinitis affects a patient's vision over time and may ultimately lead to blindness. CMV retinitis most typically affects patients with fewer than 50 CD4 T-cells, and it is estimated that the number of patients at risk for developing CMV retinitis is increasing as people with AIDS live longer.

Gilead is committed to developing important therapeutics as quickly as possible for patients with AIDS and other viral infections. In addition to VISTIDE, the Company has other nucleotide analogue product candidates in human testing for the potential treatment of CMV, HIV, herpes simplex virus and human papillomavirus (a cause of genital warts). Studies of these candidates are also ongoing for the potential treatment of herpes simplex virus, human papillomavirus and hepatitis B virus infection for patients not infected with HIV. The Company also has a protease inhibitor in preclinical development for the potential treatment of HIV.

Gilead Sciences is a leader in the discovery and development of a new class of human therapeutics based on nucleotides, the building blocks of DNA and RNA. The Company's research and development efforts encompass three interrelated programs: small molecule antivirals, cardiovascular therapeutics and genetic code blockers for cancer and other diseases. Gilead's expertise in each of these areas has also resulted in the discovery of non-nucleotide product candidates that expand the Company's technology platforms. Gilead common stock is traded on The Nasdaq Stock Market under the symbol GILD.

Full prescribing information on VISTIDE may be obtained from Gilead Medical Services 1-800 Gilead 5 (445-3235).