Investigational Vaccine May Broaden Protection Against Pneumoccocal Disease In Children

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Data from a pivotal trial and three other Phase 3 studies presented today indicate that Wyeth's (NYSE: WYE) investigational 13-valent pneumococcal conjugate vaccine (PCV13) may offer broader protection against pneumococcal disease (PD) in infants and young children compared to Prevnar, Pneumococcal 7-valent Conjugate Vaccine (Diphtheria CRM197 Protein).

Specifically, the data indicate that PCV13 may be as effective as Prevnar (also referred to as PCV7) in helping to prevent invasive pneumococcal disease (IPD) due to the seven serotypes shared by the vaccines, and may provide expanded coverage for six additional serotypes found worldwide. The data were presented at the joint annual meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) and the Infectious Diseases Society of America (IDSA) in Washington, D.C.

The candidate vaccine includes the 13 most common pneumococcal serotypes associated with serious PD. Seven of these (4, 6B, 9V, 14, 18C, 19F and 23F) are included in Prevnar -- the current global standard in PD prevention in infants and young children. The six additional serotypes (1, 3, 5, 6A, 7F and 19A) are associated with the greatest burden of residual, or remaining, invasive disease. Both vaccines contain CRM197 -- an immunological carrier protein with a 20-year history of use in pediatric vaccines.

"These new data suggest that the 13-valent pneumococcal vaccine has the potential to address a critical unmet need," says Emilio A. Emini, Ph.D., Executive Vice President, Vaccine Research and Development, Wyeth Pharmaceuticals. "Based on the known prevalence of pneumococcal serotypes, it is estimated that the candidate vaccine has the potential to cover up to 92 percent of invasive pneumococcal disease in infants and young children worldwide. Given the global burden of serious pneumococcal disease, this candidate vaccine is designed to provide more comprehensive protection."

The Company expects to complete its U.S. filing for pediatric use of the vaccine in the first quarter of 2009, with other pediatric global filings expected at the same time, or possibly earlier. The 13-valent candidate vaccine is also being studied in global Phase 3 clinical trials in adults, with regulatory filings expected in 2010.

Pneumococcal disease affects both children and adults, and is a leading cause of illness and death worldwide. Pneumococcal disease describes a group of illnesses, all caused by the bacterium Streptococcus pneumoniae, that include invasive infections such as bacteremia/sepsis and meningitis, as well as pneumonia and otitis media. Most recently, the pneumococcal serotype 19A, which is included in the candidate vaccine, has been increasing in prevalence in many regions of the world and is frequently resistant to antibiotics.

Phase 3 Data Results

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The data presented today represent four of 13 core Phase 3 studies in the pediatric clinical trial program intended to support regulatory filings for licensure of the 13-valent vaccine.

European Pivotal Data

The pivotal Phase 3 trial (#G-2117), conducted in Germany with 604 infants, compared the candidate PCV13 to Prevnar. The immunogenicity assessments were conducted at one month after completion of the infant vaccination series (using a vaccination schedule of 2, 3 and 4 months). The immunogenicity objectives of the study were to:

-- Compare the immune responses elicited by PCV13 and Prevnar against each of the seven pneumococcal serotypes common to the two vaccines.

-- Evaluate the immune response elicited by the six additional pneumococcal serotypes included in the 13-valent vaccine.

On the basis of a prospectively defined set of immunogenicity criteria, the results of the study indicated that the responses elicited by PCV13 for all 13 serotypes were comparable (scientifically referred to as "non-inferior") to those of Prevnar. Additionally, PCV13 elicited functional (biologically active) antibodies for all 13 serotypes. The results of this study also indicated that the safety and tolerability of PCV13 and Prevnar were comparable.

Finally, the study evaluated the immune responses elicited against several components (hepatitis B, Haemophilus influenzae type B and diphtheria) of the concomitantly administered Infanrix hexa (GlaxoSmithKline) pediatric vaccine. Immune responses to these vaccine antigens were comparable when co-administered with either PCV13 or Prevnar.

Overall, the results of this pivotal study suggest that PCV13 may be as effective as Prevnar in helping to prevent pneumococcal disease caused by the serotypes currently in Prevnar, and that PCV13 may provide expanded coverage in helping to prevent PD caused by the six additional serotypes.

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