Pfizer sees big Prevnar 13 sales among adults

*Could generate peak sales of $1.5 billion annually

NEW YORK Jan 12 (Reuters) - Pfizer Inc (PFE.N) on Tuesday said it plans to seek approvals this year for use of its experimental Prevnar 13 vaccine among adults, with expectations the product will eventually generate peak annual sales of more than $1.5 billion for that population.

Pfizer is awaiting U.S. approval of the improved version of its blockbuster Prevnar vaccine for infants and young children. The product, acquired through Pfizer's recent purchase of rival U.S. drugmaker Wyeth, prevents a range of infections caused by pneumococcal bacteria.

Martin Mackay, president of PharmaTherapeutics at Pfizer, told investors at the annual J.P. Morgan Healthcare Conference in San Francisco that Prevnar 13 is among the most promising of the company's products in late-stages of testing.

The current Prevnar vaccine, which protects against seven strains of streptococcus pneumoniae, is approved for infants and young children. The newer product, which protects against 13 strains of the bacterium, would be marketed to young children as well as adults over 50 years of age, if approved by regulators.

Pfizer said its other promising late-stage products include: Tanezumab, an antibody used to treat osteoarthritis; CP-690,550, a so-called JAK3 Inhibitor to treat rheumatoid arthritis; Dimebon and Bapineuzumab to treat Alzheimer's disease and PF-2341066 to treat non-small cell lung cancer.

Pfizer shares were up 4 cents to $18.87 on the New York Stock Exchange during mid-day trade. (Reporting by Ransdell Pierson, editing by Leslie Gevirtz)