Pfizer Inc shares fell 1 percent on Thursday after it said a U.S. decision on whether to approve the company's new version of its big-selling Prevnar vaccine that fights pneumonia and meningitis would push past the deadline.

The delay on action for Prevnar 13 marked the second setback this week for the world's largest drugmaker. Pfizer said on Tuesday it ended an advanced lung-cancer study for its experimental drug figitumumab after an analysis showed it was unlikely to meet the main goal of improving overall survival.

Pfizer shares were down 19 cents, or 1 percent, at $18.31 in morning trading on the New York Stock Exchange, making it the worst performer in the NYSE Arca Pharmaceutical index <.DRG> of large drugmakers.

Wall Street is worried that Pfizer lacks enough products to prop up revenue and profits when its giant-selling Lipitor cholesterol treatment loses U.S. patent protection in the next few years.

Prevnar 13 is a more protective form of the original vaccine, which was introduced in 2000. A decision by the U.S. Food and Drug Administration on Prevnar 13 had been expected by Wednesday, but Pfizer said late on Wednesday that the FDA had not yet completed its review.

Robert Hazlett, an analyst with BMO Capital Markets, said he expects Prevnar 13 to be approved in the first half of 2010. He maintained his estimate for Prevnar franchise sales of $3.7 billion in 2012.

The Prevnar 13 review appears to be another example of missed deadlines at the FDA, as Pfizer has indicated the FDA has not pointed out any issues with the application, Hazlett said in a research note.

Prevnar was one of the major franchises that Pfizer obtained in its $67 billion acquisition of Wyeth, which closed in October and helps the world's largest drugmaker diversify into vaccines and biotechnology medicines. Analysts also expect Pfizer to wring out significant cost savings through the deal.

(Reporting by Lewis Krauskopf)