Roche Seeks New Tamiflu Indication for the Prevention of Influenza

Tamiflu™ (oseltamivir phosphate), the number one prescribed antiviral treatment for influenza, now shown to prevent incidence of flu when taken once daily

Nutley, NJ -- May 23, 2000

Hoffmann-La Roche Inc. and Gilead Sciences, Inc. (Nasdaq:GILD), announced today that Roche has submitted an application to the U.S. Food and Drug Administration (FDA) for a new indication for its influenza antiviral Tamiflu™ (oseltamivir phosphate) for the prevention of naturally occurring influenza in adults and adolescents 13 years and older. Tamiflu, the first pill to treat most common strains of influenza, types A and B, received government approval in October 1999 for the treatment of uncomplicated acute illness due to influenza infection in adults.

The prevention application is supported by clinical trial data which showed that Tamiflu reduced the incidence of influenza by 92 percent in adults and adolescents who were in contact with a household member infected with the flu. Participants of this trial received one 75 mg pill of Tamiflu once daily for seven days. Additional studies also found that Tamiflu reduced the incidence of influenza in healthy adults during a community outbreak and the elderly in a nursing home setting.

“Oseltamivir (Tamiflu) has been shown in several clinical settings to be highly effective in protecting against influenza illness, and is well tolerated when taken once daily,” said Frederick G. Hayden, M.D., Stuart S. Richardson Professor of Clinical Virology and Professor of Internal Medicine and Pathology at the University of Virginia School of Medicine. “The 92 percent protection rate observed in households is exciting because it shows that oseltamivir (Tamiflu) can provide immediate protection for people who have been exposed to the virus through contact with someone infected with influenza.”

Prophylaxis Studies

The new application is supported by findings from three separate Phase III randomized, double-blind, placebo-controlled clinical trials involving 3,434 healthy patients (adolescents, adults and the elderly). In one trial, 75 mg of Tamiflu taken once daily for seven days reduced the incidence of influenza by 92 percent in adults and adolescents who were in contact with a household member infected with the flu.

In addition, Tamiflu was shown to reduce the incidence of laboratory confirmed influenza by 76 percent in healthy adults during a community outbreak and by 92 percent in the elderly in residential nursing home settings. In total, 1,480 people received the recommended dose, one 75 mg pill of Tamiflu once daily for up to 42 days.

In these studies, Tamiflu reduced the incidence of influenza among the participants, many of whom were not vaccinated. In the residential nursing home trial, the protection level of Tamiflu was demonstrated among elderly participants, 80 percent of whom had been vaccinated, suggesting that the benefits of Tamiflu complement those of vaccination. Tamiflu also reduced the incidence of influenza-associated bronchitis, pneumonia and sinusitis by 86 percent.

The Centers for Disease Control’s Immunization Practices Advisory Committee recommends early vaccination as the method for preventing influenza unless vaccination is contraindicated, not available or not feasible.

“For people who aren’t vaccinated, in cases where the vaccine does not match the influenza strain of the season, or for high-risk patients who might need additional protection, Tamiflu can provide an added means of preventing influenza illness,” said Deborah Arrindell, M.D., J.D., Medical Director of Hoffmann-La Roche Inc. “Tamiflu is the first antiviral pill that can safely protect people exposed to influenza in the home or at work, on the bus, subway or in the supermarket.”

In clinical trials, the adverse events were qualitatively similar to those seen in treatment studies, despite the longer duration of treatment, and no clinically relevant differences in safety profile were seen in the elderly patients compared to the younger population. The most frequently reported adverse events were nausea, vomiting, diarrhea and headache.

About Tamiflu

Tamiflu, co-developed with Gilead Sciences of Foster City, California, is a systemic treatment for all common strains of influenza (types A & B). The medication targets one of the two major surface structures of the influenza virus, the neuraminidase protein. The neuraminidase site is virtually the same in all common strains of influenza. If neuraminidase is inhibited, the virus is not able to infect new cells.

In its first season of availability for treatment, Tamiflu has amassed more than 58 percent of the market share within the new class of antivirals called neuraminidase inhibitors, and garnered more than 30 percent of the overall influenza antiviral market.

Influenza’s Impact

Each year, up to 40 million Americans develop the flu, resulting in an annual cost of $14.6 billion in physician visits, lost productivity and lost wages. In addition, nearly 300,000 people are hospitalized, and 20,000 to 40,000 die from influenza and its complications. The risks for hospitalization and death from influenza are higher among people ages 65 or older, and those people with underlying high-risk medical conditions.

About Hoffmann-La Roche and Gilead Sciences

Hoffmann-La Roche Inc. is a leading research-intensive pharmaceutical company that discovers, develops, manufactures and markets numerous important prescription drugs that improve, prolong and save the lives of patients with serious illnesses. Among the company’s areas of therapeutic interest are: Virology, including HIV/AIDS and hepatitis C; Infectious Diseases, including influenza; Cardiology; Neurology; Oncology; Transplantation; Dermatology; and Metabolic Diseases, including obesity and diabetes.

The company provides a wide range of medications in the United States through its marketing and sales subsidiary, Roche Laboratories Inc. Headquartered in Nutley, N.J., both companies are members of the Basel, Switzerland-based Roche Group, a global leader in health care with principal businesses in pharmaceuticals, diagnostics, vitamins, and fragrances and flavors. For more information on Roche Pharmaceuticals in the United States, visit the company’s web site at: http://www.rocheusa.com.

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 Foster City, CA; Boulder, CO; San Dimas, CA; Cambridge, UK and Dublin, Ireland and sales and marketing organizations in the United States, Europe and Australia. For more information about Gilead, please visit www.gilead.com.