FDA Panel Rejects Aviron's Nasal-Spray Flu Vaccine on Safety Concerns
Dow Jones Newswires
WASHINGTON -- A federal panel declined to endorse Aviron Inc.'s nasal-spray flu vaccine
FluMist, which would be co-marketed in the U.S. with American Home Products Corp.
The panel said Aviron's (AVIR) data proved FluMist was effective in preventing the flu, but the
group wasn't fully convinced of the vaccine's safety.
Most panelists were excited about the possibility of having the first nasal- spray vaccine
approved in the U.S., but said they need additional safety data before they would be comfortable
with the product being used in the general population.
The decision now rests with the Food and Drug Administration which will consider the panel's
votes and comments when it considers FluMist by Aug 31. Most panelists who said the safety of
FluMist wasn't established also said the vaccine will likely prove effective once all of the data is
fully analyzed and when ongoing studies are completed.
"At this time the data is not adequate," said panelist Dr. Martin Myers director of the National
Vaccine Program Office. "It is likely to prove safe, but the data and analysis is not complete."
The FDA advisory panel's decision will keep FluMist off the market this flu season, but Aviron
Chairman and Chief Executive Boyd Clarke said the company still plans to meet its primary goal
to have the product available for the 2002- 2003 flu season.
He added Aviron has much of the data the panel requested and that the company is in the
process of analyzing it before submission to the FDA.
"We will get this product over the line," Mr. Clarke vowed.
Panelists were concerned that there is no data describing how FluMist interacts with other
vaccines, especially since very young children are given many vaccinations. Also, the group said
administering the vaccine to children with asthma is a concern, although Aviron only asked the
drug to be approved in healthy people ages 1 to 64.
Panel members were also hesitant to support FluMist because of incidents of pneumonia and
fever in some of patients studied and asked for additional data on the safety of repeatedly
vaccinating adults every year, since the company only gave one dose of the vaccine to adults in
the study.
Several panelists who reviewed Aviron's data on FluMist in a two-day meeting said the drug
appeared effective in preventing the flu in people ages two to 64. However five of the 15
panelists said more data is needed to support the approval the company wants, which includes
those between the age of one and two.
"The efficacy data was really quite strong," said panelist Dr. Nancy Cox chief of the Centers for
Disease Control and Prevention's Influenza Branch. "It would be nice to have additional data on
younger children."
The flu, the common name for influenza, is a respiratory infection marked by fever, headaches,
fatigue and muscle aches.
Unlike the flu shot, which contains dead virus, FluMist is made with a weakened form of a live
virus designed to stimulate the immune system to create defenses against actual infection. FluMist
is proposed to be administered annually, with unvaccinated children under nine years of age
getting two initial doses one month apart. Since only 10% of healthy children and 30% of healthy
adults get a yearly flu vaccination, Aviron and American Home (AHP) hope the inhaled product
would expand the market.
In the companies' trials of FluMist, which was first developed in 1995, almost 20,000 children
and 5,000 adults were studied. In children, Aviron said FluMist was 87% effective. For those
who did contract the flu, FluMist cut the days the children experienced fever in half compared
with an inactive placebo.
In one study of adults, FluMist was 85% effective in preventing the flu, while the traditional flu
shot proved 71% effective.
Panelist Dr. David S. Stephens, medical professor and director of the Infectious Diseases
Division at Emory University School of Medicine, said determining what is a healthy adult will be
difficult because people often have a variety of medical conditions.
However, he said FluMist is a crucial product. "I do think this is an important vaccine," Dr.
Stephens added. "It is an important breakthrough."
Shares of Aviron weren't open for trading Friday, as the Nasdaq Stock Market halted activity
until after the panel's decision was made. Although it became public shortly before 3 p.m. EDT,
trading didn't open before regular activity ended at 4 p.m. The stock closed Thursday at $40.80.
Dr. Sharon R. Seiler, an analyst who follows Aviron for Punk, Ziegel & Co., said the panel's
vote was "clearly a setback." But, she said most panelists want more data, and thinks that data
will sway them toward approval.
Aviron will co-market FluMist in the U.S. with American Home's Wyeth Lederle Vaccines, while
in most other countries, Wyeth Lederle will sell the product.
Write to Otesa Middleton at otesa.middleton@dowjones.com
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