UPDATE 1-Wyeth says new form of Prevnar fares well in study

(Adds quotes, study data, NEW YORK dateline, byline)

By Ransdell Pierson

NEW YORK, Oct 27 (Reuters) - Wyeth (WYE.N) on Monday said trials of an improved form of its blockbuster Prevnar vaccine suggest it is as safe as the original and may offer broader protection against infections in infants and young children.

The experimental product is designed to protect against 13 serotypes -- or forms -- of a bacterium called streptococcus pneumoniae (pneumococcus) that can cause an array of diseases, ranging from ear infections to pneumonia and meningitis.

Prevnar, introduced in 2000 for infants and young children and expected to garner 2008 sales approaching $2.8 billion, protects against seven serotypes that account for about 80 percent of potential infections. Wyeth said the new product could broaden protection to against perhaps 92 percent of potential infections in infants and toddlers.

Data from four late-stage trials was presented at a medical meeting in Washington, D.C., including a "pivotal" 604-infant study conducted in Germany that is expected to be submitted to regulators by the first quarter of 2009 as part of a marketing application for the product.

Wyeth said overall results of the German study suggest that 13-valent Prevnar may be as effective as Prevnar in helping to prevent pneumococcal disease caused by the serotypes already in Prevnar, and will likely prevent disease caused by the six additional serotypes.

Effectiveness was judged by the ability of each vaccine to spur the body to make antibodies that bind to different sugars that coat pneumococcal bacteria, as well as ability to create antibodies that coax a certain type of immune system cell to devour bacteria.

The new form of Prevnar succeeded in nearly 40 assessments of immune response but narrowly missed its goal in one assessment -- of antibody-binding for a serotype called 6B that is protected against by standard Prevnar, Wyeth said.

"That's an excellent showing," said Dr. Emilio Emini, Wyeth's head of vaccine research and development. He described the narrow-miss on serotype 6B "not a big deal because it's almost impossible to achieve (all goals) in all 13 serotypes."

Wyeth said it continued to expect to seek U.S. and international pediatric approval for the 13-valent form of Prevnar by the first quarter of 2009, and aims to seek approval in 2010 to sell the new product to adults aged 50 and older.

Prevnar is not currently approved to protect adults, but sales of the 13-valent product for that population could eventually top $1.5 billion, Wyeth said.

Pneumonia caused by the pneumococcal organism is one of the most significant causes of death in older individuals and its incidence begins to increase when one is roughly 50 years old, and increases rapidly thereafter as the immune system weakens.

The mortality rate for adults with the form of pneumonia averages 10 percent to 20 percent even in developed countries, according to Wyeth, and can exceed 50 percent in high-risk patients.

Standard pneumonia vaccines now available have little or no effectiveness, and are therefore not sold in many countries, Emini said.

Combined future annual sales of 13-valent Prevnar for adults and young children could eventually exceed $4.5 billion, Wyeth said. (Editing by Leslie Gevirtz)