Roche's Tamiflu™ Granted FDA Approval for the Prevention of Influenza

-- This flu season, Tamiflu™ (oseltamivir phosphate), the number one prescribed antiviral treatment for influenza, can also be used to prevent flu when taken once daily --

Nutley, NJ -- November 20, 2000

Hoffmann-La Roche Inc. and Gilead Sciences, Inc. (NASDAQ:GILD), announced today that the U.S. Food and Drug Administration (FDA) has granted Roche marketing approval for a prophylaxis indication for its influenza antiviral Tamiflu™ (oseltamivir phosphate). Tamiflu received government approval in October 1999 for the treatment of uncomplicated acute illness due to influenza infection in adults. This flu season, Tamiflu will be available for the prevention of naturally occurring influenza A & B in adults and adolescents 13 years and older.

The results of several clinical studies show that Tamiflu is up to 92% effective in preventing influenza illness in adolescents, adults and the elderly when taken once daily. The studies examined Tamiflu’s ability to prevent the development of flu in three different settings: households, communities and residential nursing homes. The results can vary year-to-year depending on the incidence of flu.

“Last year, Tamiflu was shown to be safe and effective in treating patients who contracted the influenza virus. This year, Tamiflu will have an added benefit for physicians and their patients,” said Michael Hassman, D.O., Comprehensive Clinical Research. “Tamiflu is the first antiviral pill, effective against all common strains of flu, that can safely protect people who are in close contact with someone who has the flu.”

Tamiflu is not a replacement for vaccines. Early vaccination on an annual basis is recommended by the Centers for Disease Control’s Immunization Practices Advisory Committee unless vaccination is contraindicated, not available or not feasible.

Prophylaxis Studies
The prevention indication 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). The prophylaxis studies examined the drug’s preventative capabilities in a household setting where family members were exposed to the virus, during a community outbreak and during outbreaks within residential nursing home settings.

Post-Exposure Trial
In one trial of over 950 patients (493 patients on Tamiflu and 462 on placebo), 75mg of Tamiflu taken once daily for seven days reduced the incidence of influenza from 12% in the placebo group to 1% in the Tamiflu group (a difference of 92%) in adults and adolescents who were in contact with a household member infected with the flu.

“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 Arnold S. Monto , M.D., University of Michigan School of Public Health. “The protection rate observed in households is exciting because it shows that Tamiflu can provide immediate protection for people who have been exposed to the virus through contact with someone infected with influenza.”

Study participant Robert Stone notes that Tamiflu was able to protect his family from the flu, “My son was very sick with the flu. He had a high fever, chills, and body aches. I was certain that the rest of the family was going to get sick, so we enrolled in the Tamiflu study. I was surprised how well Tamiflu worked; my wife, our two daughters, and I all remained healthy. It is comforting to know that there was something out there to prevent us from the misery that my son went through with the flu.”

Community Outbreak and Nursing Home Outbreak Trials
Tamiflu was shown to reduce the incidence of laboratory confirmed influenza from 4.8% in the placebo group to 1.2% in the Tamiflu group (a difference of 76%) in healthy adults during a community outbreak and from 4.4% in the placebo group to 0.4% in the Tamiflu group (a difference of 92%) in the elderly in residential nursing home settings. In total, 796 people received the recommended dose, one 75 mg pill of Tamiflu once daily for up to 42 days (791 people received placebo).

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.

“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 Monto.

Tamiflu is generally well tolerated. 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. Serious bacterial infections may begin with influenza-like symptoms or may co-exist with or occur as complications during the course of influenza. Tamiflu has not been shown to prevent such complications.

About Tamiflu
Tamiflu (oseltamivir phosphate), co-developed with Gilead Sciences of Foster City, California, is a systemic treatment for all common strains of influenza (types A & B) and is available in a convenient pill form. Tamiflu was approved by the U.S. Food and Drug Administration in October 1999 for the treatment of uncomplicated influenza in adults and is now the market leader in antiviral influenza treatment. In its first season of availability for treatment, Tamiflu 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.

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.

About Hoffmann-La Roche and Gilead Sciences
Hoffmann-La Roche Inc. (Roche), based in Nutley, N.J., is the U.S. prescription drug unit of the Roche Group, a leading research-based health care enterprise that ranks among the world’s leaders in pharmaceuticals, diagnostics and vitamins. Roche discovers, develops, manufactures and markets numerous important prescription drugs that enhance people's health, well-being and quality of life. 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.

For more information on the Roche pharmaceuticals business in the United States, visit the company’s web site at: www.rocheusa.com. To learn about influenza surveillance and to find out if flu is in your area, log onto www.flustar.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.

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