By Lisa Seachrist

Washington Editor

Looking to make Tamiflu the treatment option for the entire flu-infected family, Hoffmann-La Roche Inc. filed a new drug application (NDA) for use of Tamiflu and Tamiflu oral suspension in children 12 months and older.

The move comes just one month after the Nutley, N.J.-based company submitted a supplemental NDA for Tamiflu (oseltamivir phosphate) for the prevention of flu, and signals the continuing battle for market share between Tamiflu and London-based Glaxo Wellcome plc's drug, Relenza.

"We are very excited about this filing," said Charles Alfaro, director of public affairs for Roche. "Treating children with flu is really an unmet medical need. We're very pleased with the results we've seen."

Tamiflu is an oral neuraminidase inhibitor, originally developed by Foster City, Calif.-based Gilead Sciences Inc. Roche and Gilead completed clinical development of the drug and Roche markets the product worldwide. Neuraminidase facilitates the influenza virus' ability to spread from cell to cell in the respiratory tract.

Approved just in time for the 1999-2000 flu season, Tamiflu has been fighting for market share with Glaxo's Relenza, an inhaled neuraminidase inhibitor. Al Rauch, senior vice president and biotech analyst at First Union Securities Inc. in Chicago, noted early last year Relenza had the advantage, but by the end of the year Tamiflu, with its capsule formulation, had garnered about 80 percent of the market. The company estimates its market share at 58 percent. (See BioWorld Today, July 28, 1999, p. 1; and October 29, 1999, p. 1.)

"Each one is trying to become the drug of choice to treat the flu," Rauch said. "Last year, there were definitely physicians who were using the drug off label in the pediatric populations. Having an indication for such broad pediatric use is definitely going to give Tamiflu an advantage."

The preference for an oral formulation is just what Roche is banking on. Alfaro said, "An oral formulation is more convenient, especially for children."

The basis for the NDA was findings from Phase III randomized, double-blind, placebo-controlled clinical trials of children aged 1 to 12, including 695 otherwise healthy children and 334 asthmatic children aged 6 to 12. The study involving healthy children was conducted in the U.S. and Canada while the study of asthmatic children included medical centers from 15 countries around the world. The healthy children study served as the efficacy component of this filing.

In the otherwise healthy children study, Tamiflu reduced the duration of influenza by 26 percent, allowing the children to return to normal health and activity almost two days sooner than children receiving a placebo.

The study for asthmatic children provided the company with safety information in this high-risk group. The company reported the drug was well tolerated, but noted kids from both trials receiving Tamiflu had about 5 percent more vomiting than those on the placebo arm.

"When you look at our primary endpoint of return to normal health and activity, this is a very important improvement," Alfaro said. "Children have a very high rate of influenza infection, contracting the disease at a significantly higher rate than adults. And, they are susceptible to secondary complications like otitis media."

Alfaro also pointed out by returning children to health sooner, parents could go back to the workplace sooner and children may not be so likely to infect their parents. That could be a very important benefit of treating children because every year 40 million people develop the flu, at an estimated annual cost of $14.6 billion in physician visits, lost productivity and lost wages.

"We're really pleased the program is moving along so well," said Sheryl Meredith, a spokeswoman for Gilead. "Children are really [sources] for this disease. Hopefully, this will allow more individuals who come in contact with influenza to avoid getting sick."

Gilead received a milestone payment in May for the prophylaxis indication; however, there was no milestone associated with the pediatric filing. (See BioWorld Today, May 24, 2000, p. 1.)

Neither Alfaro nor Meredith could speculate about how fast a pediatric indication would be reviewed by FDA, but Alfaro did say the company was in discussion with the agency.

Gilead's stock (NASDAQ:GILD) closed Friday at $65.75, up $1.375.

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