ATLANTA — Wyeth Pharmaceuticals is in the process of planning the transition from routine childhood immunization with the 7-valent Prevnar to use of a 13-valent pneumococcal conjugate vaccine that is still under investigation.
The Food and Drug Administration has granted fast-track status for PCV13 for the pediatric indication, based on “an unmet medical need.” The company planned to complete the data submission process for PCV13 by the end of March, at which point the agency would decide about priority review, Peter Paradiso, Ph.D., vice president of new business and scientific affairs at Wyeth, Collegeville, Pa., said at the winter meeting of the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention.
The 13-valent version contains the same amounts of the same seven serotypes that Prevnar has (4, 6B, 9V, 14, 18C, 19F, and 23F) along with six new strains (1, 3, 5, 6A, 7F, and 19A). Each of these polysaccharides in both vaccines is conjugated to the same carrier protein, CRM197, he noted.
Since the introduction of Prevnar in 2000, the proportion of cases of invasive pneumococcal disease (IPD) caused by the seven vaccine strains has declined dramatically, while the proportion caused by other strains—19A in particular—has risen.
Dr. Paradiso summarized previously reported data from a pivotal trial done in Germany in which 603 infants received either PCV7 or PCV13 at 2, 3, and 4 months of age. The 13-valent version was noninferior against each serotype, while provoking a high antibody response rate to each of the six new serotypes.
Wyeth's transition scheme—which would be subject to approval by both the FDA and the ACIP after PCV13 is licensed—would involve the substitution of PCV13 for PCV7 at any point in the immunization schedule.
Since data show that a single dose of PCV13 will induce an immune response to the six new serotypes in more than 90% of children aged 12 months and older, any child who received the primary 3-dose series with PCV7 could simply receive PCV13 as a booster after the age of 12 months. For children 12 months and older who already received the complete series with PCV7 including the booster, one additional dose of PCV13 would be needed. Infants aged 6 months or younger who received one or two doses of PCV7 would complete the primary series and the booster using PCV13.
The company will first seek an indication for the use of PCV13 in children under 5 years old. It then hopes to bring it to adults over age 50, and ultimately to the entire population, Dr. Paradiso said.