By Kim Coghill

Washington Editor

Gilead Sciences Inc. said Thursday that its marketing partner, Hoffmann-La Roche Inc., has received FDA approval to market Tamiflu, an antiviral influenza therapeutic for children ages 1 to 12.

The pediatric indication, which will be available by mid-January in a tutti frutti-flavored liquid suspension, is for the treatment of acute illness due to influenza in children who have been symptomatic for no more than two days. The liquid also can be used by adults who cannot swallow a capsule.

In October 1999 Tamiflu was approved for treatment of influenza infection in adults and adolescents, and in November it was approved for prophylaxis indication, also for adults and adolescents. (See BioWorld Today, Nov. 21, 2000, and Oct. 29, 2000.) Tamiflu (oseltamivir phosphate) treats the most common strains of influenza, types A and B.

"The flu for years has been a fairly undertreated disease in all populations," said Charles Alfaro, director of public affairs for Nutley, N.J.-based Hoffmann-La Roche. "It is a disease that people ride out. When you look at the adult population alone, up to 40 million Americans a year may come down with the flu and leave the disease untreated and stay at home and are miserable. Now there's a treatment option for both adults and children all the way down to age 1 that is effective against all common strains and can reduce the duration."

Analysts expect that Tamiflu likely will benefit children more than adults, since children are more susceptible to infection.

In a written analysis, John Sonnier, senior biotech analyst for Prudential Vector Healthcare Group in Deerfield, Ill., said sales due to the expanded market of Tamiflu likely will grow from $57 million in 2000 to $201 million in 2001 with royalties to Gilead of $12 million and $34 million, respectively.

Prudential Vector considers Gilead a "strong buy," the analysis said. Gilead's stock (NASDAQ:GILD) closed Friday at $77.187, down 62.5 cents.

Pediatric clinical studies show that Tamiflu reduced the duration of influenza by 1.5 days in children ages 1 to 12 when given within two days of onset of symptoms.

The new indication is supported by findings from Phase III randomized, double-blind placebo-controlled clinical trials involving 1,032 children ages 1 to 12, including 698 otherwise healthy children ages 1 to 12 and 334 asthmatic children ages 6 to 12. In total, 515 patients received the Tamiflu oral suspension formulation.

Tamiflu was well-tolerated and the most common adverse event was vomiting. The product is not a replacement for vaccines.

"Tamiflu is a tremendous option that helps relieve the misery of children and reduces the duration of the time they are sick," Alfaro said.

Tamiflu already has taken 58 percent of the neuraminidase inhibitor market, where its only competitor is Relenza (zanamivir), marketed by London-based Glaxo Wellcome plc, and 30 percent of the flu market, which includes other drugs for relief of the troublesome seasonal ailment.