By Lisa Seachrist

Washington Editor

WASHINGTON — Yearly painful flu shots are one step closer to becoming a mere memory.

Mountain View, Calif.-based Aviron has submitted its first product for FDA review by filing product and establishment license applications (PLA/ELA) for FluMist, the company's intranasal attenuated influenza vaccine. The vaccine has been shown to be effective in both adults and children.

"It's an exciting milestone for the company," said J. Leighton Read, president and CEO of Aviron.

However, patients eager to gain protection from the flu without getting stuck with a needle will have to wait at least for the 1999-2000 flu season.

"FDA and Aviron have a lot of work to do to allow this product to be ready for the 1999 flu season," said Read. "We are committed to working with the agency in order to get approval in the fastest time frame possible."

Epidemic influenza affects approximately 10 to 20 percent of the U.S. population each year, causing 35 million to 50 million cases of illness and 20,000 deaths.

Aviron Seeks Broad Label For Vaccine

Aviron is asking the FDA to approve FluMist to prevent influenza and its complications in both children and adults. In addition, the company is seeking an indication for FluMist when co-administered with the flu shot for high risk adults, such as the elderly.

In May, the company reported in the New England Journal of Medicine that FluMist provided 93 percent protection against influenza. Only 1 percent of 1,070 children who received the vaccine developed culture-confirmed influenza during the 1996 flu season, compared with 18 percent of 532 children who received a placebo. In addition, only one child of the 1,070 vaccinated with FluMist developed otitis media, compared to 20 of the 532 in the placebo group.

In a challenge study of healthy adults, FluMist offered an 85 percent protection rate against influenza. Those receiving a standard flu shot experienced a 71 percent protection rate.

The company also is studying whether FluMist vaccination can reduce the number of days missed from work and health care dollars spent treating the illness in adults. Side effects of the immunization include a short-lived runny nose and sore throat.

In order to support use for the elderly, the company is relying on safety trial data generated by the National Institute of Allergy and Infectious Diseases, in Bethesda, Md., which showed FluMist added 61 percent protection to that afforded by the standard flu shot among elderly patients. That additional protection provided between 75 percent and 88 percent protection from the flu.

Aviron's flu vaccine, like other modified live-virus vaccines, produces an infection without causing illness.

FluMist is a cold-adapted trivalent vaccine containing two different influenza A strains and one influenza B strain which are selected each year by an FDA committee based on worldwide surveillance. The internal flu proteins from these master strains of influenza A and B virus grow at cooler temperatures and combine with hemaglutinin and neuraminidase, the surface proteins found on contemporary circulatory viruses.

In addition to being delivered in a nasal spray rather than an injection, FluMist stimulates the mucosal immune system as well as the systemic immune system resulting in a strong cytotoxic T cell response.

Wyeth Ayerst Laboratories, of King of Prussia, Pa., studied the vaccine from 1989 to 1993 before dropping development. In 1995, Aviron licensed the vaccine from the University of Michigan, Ann Arbor, and entered into a cooperative research and development agreement with NIAID for its development into a commercial product.

"This vaccine was supported solely by [NIAID] at a time when commercial companies weren't interested in it," Read said. "They have been excellent partners and deserve a lot of the credit for its success."

Aviron's stock (NASDAQ:AVIR) closed Wednesday at $30.75, down $0.438. *