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Novavax delays testing on flu vaccine

ROCKVILLE, Md. (AP) -- Novavax Inc. said Tuesday that the next mid-stage trial of its influenza vaccine will be delayed until 2013. The trial had been expected to start in the fourth quarter of this year.

The company announced preliminary results from mid-stage testing of an experimental vaccine designed to protect against four strains of the influenza virus. The company reported that the 500-patient study of the vaccine achieved its primary goal of safely triggering an immune system response to the four viral strains.

However, the vaccine did not completely meet a second goal needed to win accelerated approval from the Food and Drug Administration. Patients achieved the FDA's requirement for antibody production for three of the viral strains, but not the fourth.

The FDA grants accelerated approval to promising medical products designed to treat serious diseases.

"While the data from this trial were positive on balance, we are evaluating both process and assay refinements that we believe will further improve the immunogenicity profile of our vaccine, pushing the start of our next phase II trial into 2013, rather than the fourth quarter of this year," Novavax CEO Stanley Erck said.

Novavax announced the trial results after the close of trading on Wall Street on Tuesday. Earlier, its shares fell 12 cents, or 6.5 percent, to close at $1.72. In extended trading, they slipped 1 cent.