Wednesday, November 18, 2009

FDA Advisory Board Votes Pfizer's Prevnar Vaccine As Effective

By Kristina Peterson, Of DOW JONES NEWSWIRES

WASHINGTON -(Dow Jones)- An advisory board to the Food and Drug Administration recommended Wednesday that a new version of the children's vaccine Prevnar be considered safe and effective.

Now marketed by Pfizer Inc. (PFE), the Prevnar 13 vaccine purports to prevent more strains of the streptococcus pneumoniae bacteria that cause illnesses like ear infections, pneumonia and meningitis.

The advisory board voted 10-1 that the vaccine should be considered both effective and safe. However, several advisers expressed concern over data from clinical trials showing that the new vaccine had not proved more effective than the original Prevnar vaccine in two of the original strains and one new strain.

"There was a slightly lower response, but in terms of functional activity, they're very similar," said Dr. Emilio Emini, chief scientific officer for Pfizer's vaccine research.

The vaccine is typically administered to infants in a series of four doses when they are 2, 4 and 6 months old, and then as toddlers between the ages of 12 and 15 months old.

The original Prevnar vaccine developed by Wyeth has significantly decreased the prevalence of pneumococcal diseases among children since it was introduced in 2000. The Centers for Disease Control and Prevention estimated Prevnar prevented 210,000 cases of pneumococcal disease between 2001 and 2007, said CDC medical epidemiologist Dr. Matthew Moore.

Between 1998 and 2007, the vaccine reduced the number of cases by 76%, said Dr. Bill Gruper, Pfizer's senior vice president of vaccine clinical research. The updated vaccine would target the strains still making children sick, including the most common strain, called 19A, which is resistant to many antibiotics. In 2005, the 19A strain caused 40% of invasive pneumococcal diseases among children younger than 5 years old, according to Pfizer.

Though Pfizer could not do full clinical trials using a placebo, the company did find in non-inferiority trials that the new vaccine is a significant improvement over its predecessor in all but one of the six additional strains.

Vicky Debold, director of patient safety at the National Vaccine Information Center and the advisory board's consumer representative, voted against considering the vaccine safe and effective. She asked if new vaccines would be continuously needed.

Parents will ask, "Is there an end to this or are we going to have to continue to deal with the emergence of antibiotic pneumococcal strains?" Debold said.

-By Kristina Peterson, Dow Jones Newswires; 202-862-6619; kristina.peterson@

(END) Dow Jones Newswires


Copyright (c) 2009 Dow Jones & Company, Inc.

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