UPDATE 1-U.S. panel votes against new bug-based flu vaccine

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By Maggie Fox, Health and Science Editor

BETHESDA, Maryland Nov 19 (Reuters) - More safety data would be needed before a new type of influenza vaccine made in insect cells should get approval, federal advisers said on Thursday.

A divided committee advising the U.S. Food and Drug Administration said the new Protein Sciences Corp FluBlok vaccine appears effective among adults under age 50 but said the company has not shown that it is safe enough to be approved.

The vaccine is made using genetically engineered pieces of flu virus inserted into caterpillar cells, instead of the current method of growing virus in chicken eggs. The company says it could produce a vaccine much more quickly -- in two months, versus five to six months for vaccines made using eggs.

"This is a promising technology, and I think we need it," said Dr. Bruce Gellin, head of the Health and Human Services Department's National Vaccine Program Office and a member of the panel. He said companies making such new vaccines would be paying close attention to the panelists' comments.

The U.S. government is struggling to vaccinate the population against H1N1, which the U.S. Centers for Disease Control and Prevention estimates has infected 22 million Americans and killed 3,900 since April.

Fewer than 50 million doses of H1N1 vaccine are now available.

Some panel members were concerned about some side-effects seen in a few of the 3,200 people who volunteered to test it, such as a woman who had Bell's palsy, a temporary paralysis of the face, that flared up an hour after she was vaccinated.

They also worried that several people who volunteered to test the vaccine had been "lost to follow-up", meaning the researchers had been unable to find out how they fared after being vaccinated.

"I don't feel the safety database is large enough," said Pamela McInnes of the National Institutes of Health. She said the vaccine is a new formulation and so the burden of proof is higher than simply changing the influenza strain from one season to another.

"I feel the safety data do not raise significant red flags," disagreed Dr. Jack Stapleton of the University of Iowa.

"What we are dealing with, rock bottom, is a pretty mediocre vaccine,' said Dr. Theodore Eickhoff, a professor emeritus at the University of Colorado School of Medicine and a panel member.

The vaccine is made using cells from a caterpillar and would be the first influenza vaccine made using cell cultures approved in the United States.

The FDA usually follows the recommendations of its advisory committees.

The Vaccines and Related Biological Products Advisory Committee said the data show the vaccine works well enough in adults aged up to 50, but six of 11 members said studies do not show the vaccine works safely.

Connecticut-based Protein Sciences, a closely held biotech, won a $35 million federal contract in June to make vaccines for pandemic influenza. The contract could be expanded over five years for a total of nearly $150 million.

Protein Sciences tested a formulation for seasonal influenza vaccine, but it could easily be changed to cover pandemic H1N1 swine flu. (Editing by Gerald E. McCormick and Carol Bishopric)