Pfizer Pulls the Pin on Bextra

Updated from 11:38 a.m. EDT

Pfizer(PFE Quote) shares fell Thursday after the drugmaker agreed to a Food and Drug Administration request to withdraw its controversial arthritis drug Bextra.

Regulators also called for a so-called black box warning on the drugmaker's Celebrex, a bigger part of Pfizer's arthritis franchise. The black-box warning is the most serious warning required by the FDA, and it greatly limits a drug's usage and appeal as well as a company's advertising efforts.

The FDA action on Bextra is a result of the agency's conclusion that "the overall risk vs. benefit profile for the drug is unfavorable," the FDA said. Pfizer has agreed to the request, even though it disagrees with the finding.

"Today's actions protect and advance the health of the millions of Americans who rely on these drugs every day," said Dr. Steven K. Galson, acting director of FDA's Center for Drug Evaluation and Research. "FDA is providing the public information based on the latest available scientific data to guide the careful and appropriate use of these drugs aimed at maximizing their potential benefits and minimizing their risks."

Pfizer said it "respectfully disagrees" with the FDA's assessment of Bextra's risks vs. benefits. Pfizer said it "will explore options" with the agency to determine under what circumstances Bextra might be returned to the market.

Pfizer said it will talk to the FDA about the precise wording of the new Celebrex label. "Pfizer has accumulated extensive Celebrex clinical data over the past 10 years involving more than 40,000 patients," the company said. As it noted last year, Pfizer repeated Thursday that it plans to conduct additional long-term clinical studies on the risks and benefits of Celebrex.

The announcement will clearly have an impact on Pfizer's bottom line. Celebrex produced $3.30 billion in sales last year while Bextra added $1.29 billion. Still, analysts had discounted the future sales impact of both products, with many figuring the drugs would produce perhaps half the sales in 2005 that they did in 2004. Now, analysts will have to revise their economic models again as they speculate if Pfizer will have to cut more costs to make up for lost revenue.