FDA advisory panel backs expanded pneumococcal vaccine

Cumulative data from 15 safety and immunogenicity trials support licensure of a 13-valent pneumococcal conjugate vaccine, the FDA’s Vaccines and Related Biologicals Advisory Committee agreed today.

If the FDA follows the committee’s recommendations and approves the four-dose regimen, it will provide additional protection against six strains of Streptococcus pneumoniae that are not included in the currently licensed seven-valent pneumococcal conjugate vaccine (PCV7, Prevnar). These additional strains were responsible for 62% of invasive pneumococcal diseases in children younger than 5 in 2007.

Studies of the investigational 13-valent pneumococcal conjugate vaccine (13vPnC, Pfizer) and PCV7 revealed comparable antibody responses among the seven strains contained in both vaccines (4, 6B, 9V, 14, 18C, 19F and 23F).

Noninferiority criterion for the six additional strains (1, 3, 5, 6A, 7F, and 19A), based on the lowest antibody response among PCV7 strains, indicated that each of the additional strains were comparable, except serotype 3, which failed to meet primary and secondary endpoints.

The addition of the 19A serotype is important, because this strain has increased in prevalence as PCV7 use increased, said panel member Patricia Ferrieri, MD.

The most commonly reported adverse events associated with the 13-valent vaccine were mild, including tenderness and irritability, safety data indicated, and occurrence rates were similar to those experienced by PCV7 recipients.

Committee members voted 10 to 1 that the vaccine, administered at 2, 4, 6 and 12-15 months, was safe and effective. The panel was divided as to whether the data were strong enough to endorse an indication for otitis media caused by the additional six serotypes, and favored keeping the current indications for the seven serotypes common to PCV7 until more data become available.

“Otitis media is not the main driver for pneumococcal vaccine,” said Matthew Moore, MD, MPH, of the CDC, who added that 13vPnC is expected to protect against between 80% and 90% of pneumococcal serotypes seen worldwide. – by Nicole Blazek