WASHINGTON (Legal Newsline) -The U.S. Supreme Court on Monday dealt pharmaceutical giant Pfizer Inc. a major legal blow, rejecting its appeal of a securities lawsuit over its pain medication Celebrex.

Plaintiffs in the case alleged that Pfizer's Pharmacia unit deliberately withheld the conclusions of a study showing that there was no advantage to using Celebrex over similar, less expensive drugs.

Urging dismissal of the lawsuit, Pfizer said investors filed their lawsuit after the two-year statute of limitations expired. For their part, plaintiffs said they did not know Pfizer may have broken the law until an August 2001 story in the Washington Post revealed the possible fraud.

Therefore, they argued that their lawsuit, filed in April 2003, was valid. Last year, the 3rd U.S. Circuit Court of Appeals, based in Philadelphia, ruled the lawsuit was filed in time.

By not agreeing to hear the case, the U.S. Supreme Court let that ruling stand.

Celebrex, a Cox-2 inhibitor, was approved by the U.S. Food and Drug Administration to treat common pain and inflammation.

A week ago, the justices ruled that investors didn't wait too long to file securities lawsuits against Merck & Co. for allegedly misrepresenting the safety of its now-off-the-market painkiller Vioxx.

The drug was taken off the market after studies showed Vioxx increased the risk of heart attacks and strokes. Celebrex is still used, but contains a black box warning about its side effects.

From Legal Newsline: Reach staff reporter Chris Rizo at chrisrizo@legalnewsline.com.