Prevnar 13: Phase III data

The double-blind, international Phase III Study 3005 trial in 938 healthy adults >=70 years of age who had previously been vaccinated with Pneumovax 23 pneumococcal vaccine showed that a single dose of Prevnar 13 met the primary endpoint by demonstrating non-inferior immunogenicity compared to Pneumovax for the 12 serotypes common to both vaccines. Prevnar 13 also met the secondary endpoint of inducing a significantly higher functional antibody response as measured by serotype specific anti-pneumococcal OPA titers at 1 month compared to Pneumovax for the majority of the serotypes (10 of 12) common to both vaccines, as well as for serotype 6A, which is only included in Prevnar 13.

All subjects received a follow-up dose of Prevnar 13 given 1 year later. Pfizer said the second dose of the vaccine in subjects who initially received a single dose of Prevnar 13 was at least as immunogenic as the initial dose for all 13 serotypes. However, in subjects who initially received Pneumovax followed by Prevnar 13 given 1 year later, the functional antibody response for the majority of serotypes was "less robust" compared to a single dose of Prevnar 13. Furthermore, the functional antibody response after a follow-up dose of Prevnar 13 in subjects who initially received a single dose of Prevnar 13 was significantly higher for the majority of the serotypes (12 of 13) compared with the Prevnar 13 response in subjects who initially received a single dose of Pneumovax. The trial is 1 of 6 Phase III trials in the Prevnar 13 adult clinical trial program in about 6,000 adults aged 50 years and older. Data were presented at the European Congress of Clinical Microbiology and Infectious Diseases and at the International Congress of Chemotherapy in Milan. ...