November 11, 2004
A University of Pennsylvania researcher says patients taking Pfizer's Bextra may double their risk of suffering a heart attack or stroke. The company called the claim "unsubstantiated" and said a recent analysis found no cardiovascular problems among arthritis patients taking Bextra.
Bextra is one of the few alternative COX-2 pain killers for patients who had been using Merck's Vioxx, withdrawn from the market in September following studies which found the drug increased the risk of heart attack and stroke in patients who took it for more than 18 months.
Last month, Pfizer conceded that Bextra was linked to increased risk of heart attack and stroke in a study of coronary bypass patients but said the risk did not extend to other users.
The latest finding comes from Garret A. FitzGerald, of the Center for Experimental Therapeutics at the University of Pennsylvania, a prominent COX-2 researcher. He presented his findings at a meeting of the American Heart Association.
FitzGerald, who has not yet published his findings in a peer-reviewed journal, says the patients in his analysis are "the canary in the coal mine" -- an early-warning sign for the millions of patients who have not yet been harmed.
FitzGerald said his findings strongly suggest that patients at risk of heart attack and strokes should avoid COX-2 medications while lower-risk patients should take them only with great caution.
FitzGerald acknowledges limitations in his study but says the Vioxx withdrawal has put the burden of proof on the drug companies to show conclusively that the COX-2 drugs are safe.
FitzGerald's study did not include Pfizer's other COX-2 drug, Celebrex, a much bigger seller than Bextra.
FitzGerald's analysis was based on 7,771 patients; 5,930 took Bextra while 1,841 took a placebo. There were 45 heart attacks and strokes among patients taking Bextra, seven in the placebo group. That translates into an approximately 2.2 times higher risk of a heart attack or stroke for those taking Bextra.
With an estimated seven million patients having taken Bextra since its introduction in 2001, more than 150,000 patients could have experienced ill effects if FitzGerald's analysis is accurate.
