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Pfizer Announces Phase III Results for Prevnar 13 Pneumococcal Vaccine in Adults Aged 18 to 49 Years

Current U.S. indication is for children and adults over 50 (Oct. 4)

On October 4, Pfizer Inc. announced top-line data assessing the immunogenicity, tolerability, and safety of Prevnar 13 (pneumococcal polysaccharide conjugate vaccine [13-valent, absorbed]) in adults 18 to 49 years of age.

The primary objective of the study was to demonstrate that the immune response to Prevnar 13 in the 18- to 49-year-old age group is noninferior to the immune response to the vaccine in the 60- to 64-year-old age group, as measured by serotype-specific opsonophagocytic assay (OPA) titers 1 month after vaccination. The primary objective was met for all 13 serotypes in Prevenar 13.

Pneumococcal disease is associated with significant mortality and morbidity for individuals of all ages. According to the company, Prevnar 13 provides the broadest coverage of any pneumococcal conjugate vaccine and has proven effectiveness against invasive pneumococcal disease in children less than 2 years of age when used as part of a routine pediatric immunization program.

Study 6115A1-004 is a pivotal, phase III, multicenter trial designed to compare the immunogenicity, tolerability, and safety of Prevnar 13 with that of the currently licensed nonconjugated pneumococcal polysaccharide vaccine (PPSV) in 740 adults 60 to 64 years of age who were naïve to PPSV, using a randomized, modified double-blind design. The study also assessed the immunogenicity, tolerability, and safety of Prevnar 13 administered open-label to 370 adults 50 to 59 years of age, compared with adults 60 to 64 years of age. In addition, 900 healthy adults 18 to 49 years of age were assessed. These participants received open-label Prevnar 13 to evaluate the immune response to Prevnar 13 in that younger age group and to compare immune responses with those of participants 60 to 64 years of age. Serotype-specific anti-pneumococcal functional antibodies were measured for all 18- to 49-year-old participants prior to vaccination, at 1 month following vaccination, and at 1 year following vaccination.

A detailed analysis of these immunogenicity and safety data will be submitted for future publication. Data concerning the 50-year-old and older cohorts were previously presented at the 21st European Congress of Clinical Microbiology and Infectious Diseases in 2011.

Pneumococcal disease (PD) is a group of illnesses caused by the bacterium Streptococcus pneumoniae, also known as pneumococcus. It can affect people of all ages, although older adults, young children, and individuals with certain chronic medical conditions are at increased risk. PD is associated with significant morbidity and mortality.

Noninvasive PD includes nonbacteremic pneumococcal pneumonia (acute lower respiratory infection that affects the lungs), which is the most common form of PD in adults, as well as sinusitis (upper respiratory tract infection) and acute otitis media (middle-ear infection, most often found in children). Invasive manifestations of the disease include bacteremic pneumonia (lung infection with bacteria in the blood), bacteremia (bacteria in the blood) and meningitis (infection of the tissues surrounding the brain and spinal cord).

In the U.S., Prevnar 13 is indicated for adults 50 years of age and older for the prevention of pneumococcal pneumonia and invasive disease caused by 13 S. pneumoniae strains (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F). This indication is based on immune responses to the vaccine. In children 6 weeks through 5 years of age, Prevnar 13 is indicated for the prevention of invasive disease caused by these same strains, and for the prevention of ear infection caused by 7 of the 13 strains.

Prevnar 13 is not 100% effective and will only help protect against the 13 strains included in the vaccine. The effectiveness of Prevnar 13 when given less than 5 years after a pneumococcal polysaccharide vaccine is not known.

For more information, visit the Pfizer Web site.

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