New Phase 3 Data Continue to Indicate that Wyeth’s Investigational 13-valent Vaccine Has the Potential to Broaden Coverage Against Pneumococcal Disease

COLLEGEVILLE, Pennsylvania - New data from Phase 3 European clinical trials reinforce that Wyeth’s (NYSE: WYE) investigational pneumococcal vaccine, Prevenar 13* (Pneumococcal Polysaccharide Conjugate Vaccine, 13-valent [Adsorbed]), has the potential to provide coverage against the 13 most prevalent serotypes associated with pneumococcal disease (PD), the leading cause of vaccine-preventable death in children younger than five worldwide.

The Phase 3 data presented at the 27th Annual Meeting of the European Society for Pediatric Infectious Diseases (ESPID) come from seven core studies in the pediatric clinical trial program for Prevenar 13 which were conducted in France, Italy, Poland, Spain and the UK. Researchers also presented health economic models which estimated the potential public health and economic impact of Prevenar 13 — if approved and incorporated into national immunization programs — for the Netherlands, the UK, as well as Germany and the U.S.

“Our investigational vaccine, Prevenar 13, builds on the scientific foundation of Prevenar and is designed to provide more comprehensive protection against pneumococcal disease,” says Emilio A. Emini, Ph.D., Executive Vice President, Vaccines Research and Development, Wyeth Pharmaceuticals. “These new data indicate that Prevenar 13 has the potential to provide direct coverage of the 13 most common disease-causing serotypes, including 3, 6A and 19A, which have been increasing in prevalence in many regions around the world.”

Prevenar 13 includes the seven serotypes (4, 6B, 9V, 14, 18C, 19F and 23F) in Prevenar* (Pneumococcal Polysaccharide Conjugated Vaccine, [Adsorbed]) — the current global standard in PD prevention in infants and young children as well as six additional serotypes (1, 3, 5, 6A, 7F and 19A) associated with the greatest remaining burden of invasive disease. Both Prevenar 13 and Prevenar use CRM197 — an immunological carrier protein with a 20-year history of use in pediatric vaccines.

Phase 3 Data Results

Data from the studies presented at ESPID indicate that Prevenar 13 is immunogenic for all serotypes and showed a safety profile similar to Prevenar. Among the study findings:

- In a study conducted in France, 613 children were randomized to receive either four doses of Prevenar or Prevenar 13 at 2, 3, 4 and 12 months, or three doses of Prevenar at 2, 3 and 4 months with a booster dose of Prevenar 13 or Prevenar at 12 months. Antibody response was measured at month 13. Both of the Prevenar 13 schedules induced a robust immune response for all 13 serotypes. - In a study conducted in Italy, 606 healthy infants aged 3 months were randomized to receive Prevenar 13 or Prevenar along with Infanrix hexa(R) [GlaxoSmithKline], the combined diphtheria, tetanus, pertussis, hepatitis B, inactivated poliovirus, and Hib vaccine, at 3, 5, and 11 months of age. Assessment of functional antibody levels (serotype specific opsonphagocytic assay) one month after the infant series and after the booster dose showed that a high percentage of infants receiving Prevenar 13 had functional antibodies for all serotypes. Prevenar 13 did not affect responses to the concomitantly administered vaccine and showed a safety profile comparable to Prevenar. - A study of 352 children in Poland assessed the safety and immunogenicity of Prevenar 13 in older children not previously immunized with Prevenar. Children were vaccinated with one of three different catch-up schedules currently recommended for Prevenar. These treatment schedules included the following: 1) two doses of Prevenar 13 at age 7 to <12 months with a booster at age 12-16 months; 2) two doses of Prevenar 13 at age 12 to <24 months; and 3) a single dose of Prevenar 13 at age 24 to <72 months. Each of the 3 regimens was shown to elicit immune response levels against all 13 serotypes that were either comparable to or greater than the IgG antibody concentrations achieved in infants after a 3-dose infant series and to have acceptable tolerability and safety profiles.

Overall, the most frequently reported adverse events in the Phase 3 trials included injection site reactions, (redness, swelling, and tenderness), fever (greater than or equal to 38 degrees C/100.4 degrees F), irritability, drowsiness, restless sleep, decreased appetite, vomiting, diarrhea and rash.

Health Economic Models

Three health economic models presented at ESPID estimated the potential public health and economic impact of Prevenar 13. The results of the analyses in the Netherlands, the UK, and Germany and the US suggested that the introduction of Prevenar 13, if approved, to national immunization programs has the potential to further reduce PD levels in children who are vaccinated as well as in the unvaccinated population (through a herd effect). Based on these economic models, the researchers estimated that routine vaccination with Prevenar 13 could be cost effective or cost saving.

Registration Status

To date, Wyeth has submitted regulatory applications for the pediatric use of Prevenar 13 in more than 45 countries. In December 2008, Wyeth submitted a marketing authorization application (MAA) for Prevenar 13 to the European Medicines Agency (EMEA). In March 2009, Wyeth submitted a Biologic License Application (BLA) for Prevenar 13 to the U.S. Food and Drug Administration (FDA). Last month, the FDA granted the BLA priority review — a designation given to products that, if approved, would be a significant therapeutic or public health advance. Prevenar 13 is also being studied in global Phase 3 clinical trials in adults, with regulatory submissions expected in 2010.

Pneumococcal Disease

Pneumococcal disease is complex and describes a group of illnesses, all caused by the bacterium Streptococcus pneumoniae. Pneumococcal disease affects both children and adults, and includes invasive infections such as bacteremia/sepsis and meningitis, as well as pneumonia and otitis media (middle ear infection).

Most recently 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.

Indication for Prevenar

Prevenar is indicated for active immunization against disease by Streptococcus pneumoniae serotypes 4, 6B, 9V, 14, 18C, 19F and 23F (including sepsis, meningitis, pneumonia, bacteremia, and acute otitis media) in infants and children from 2 months up to 5 years of age.

Important Safety Information for Prevenar

In clinical studies (n=18,168), the most frequently reported adverse events included injection site reactions, fever (greater than or equal to 38 degrees C/100.4 degrees F), irritability, drowsiness, restless sleep, decreased appetite, vomiting, diarrhea, and rash.

Risks are associated with all vaccines, including Prevenar. Hypersensitivity to any vaccine component, including diphtheria toxoid, is a contraindication to its use. Prevenar does not provide 100% protection against vaccine serotypes or protect against non vaccine serotypes. The decision to administer Prevenar should be based on its efficacy in preventing invasive pneumococcal disease (IPD).

About Wyeth Pharmaceuticals

Wyeth Pharmaceuticals, a division of Wyeth, has leading products in the areas of women’s health care, infectious disease, gastrointestinal health, central nervous system, inflammation, transplantation, haemophilia, oncology, vaccines and nutritional products.

Wyeth is one of the world’s largest research-driven pharmaceutical and health care products companies. It is a leader in the discovery, development, manufacturing and marketing of pharmaceuticals, vaccines, biotechnology products, nutritionals and non-prescription medicines that improve the quality of life for people worldwide. The Company’s major divisions include Wyeth Pharmaceuticals, Wyeth Consumer Healthcare and Fort Dodge Animal Health.

The statements in this press release that are not historical facts are forward-looking statements that are subject to risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. In particular, clinical trial data are subject to differing interpretations, and the views of regulatory agencies, medical and scientific experts and others may differ from ours. There can be no assurance that Prevenar 13 will ever receive regulatory approval or be successfully developed and commercialized. Other risks and uncertainties that could cause actual results to differ materially from those expressed or implied by forward-looking statements include, among others, risks related to our proposed merger with Pfizer, including satisfaction of the conditions of the proposed merger on the proposed timeframe or at all, contractual restrictions on the conduct of our business included in the merger agreement, and the potential for loss of key personnel, disruption in key business activities or any impact on our relationships with third parties as a result of the announcement of the proposed merger; the inherent uncertainty of the timing and success of, and expense associated with, research, development, regulatory approval and commercialization of our products and pipeline products; government cost-containment initiatives; restrictions on third-party payments for our products; substantial competition in our industry, including from branded and generic products; emerging data on our products and pipeline products; the importance of strong performance from our principal products and our anticipated new product introductions; the highly regulated nature of our business; product liability, intellectual property and other litigation risks and environmental liabilities; the outcome of government investigations; uncertainty regarding our intellectual property rights and those of others; difficulties associated with, and regulatory compliance with respect to, manufacturing of our products; risks associated with our strategic relationships; global economic conditions; interest and currency exchange rate fluctuations and volatility in the credit and financial markets; changes in generally accepted accounting principles; trade buying patterns; the impact of legislation and regulatory compliance; risks and uncertainties associated with global operations and sales; and other risks and uncertainties, including those detailed from time to time in our periodic reports filed with the Securities and Exchange Commission, including our current reports on Form 8-K, quarterly reports on Form 10-Q and annual report on Form 10-K, particularly the discussion under the caption “Item 1A, Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2008, which was filed with the Securities and Exchange Commission on February 27, 2009. The forward-looking statements in this press release are qualified by these risk factors. We assume no obligation to publicly update any forward-looking statements, whether as a result of new information, future developments or otherwise.

* Trademark

Source: Wyeth Pharmaceuticals

Media, Lili Gordon, Wyeth Pharmaceuticals, +1-484-865-6671, or Douglas Petkus, Wyeth, +1-973-660-5218, or Investors, Justin Victoria, Wyeth, +1-973-660-5340