A scientist’s claim of evidence that Pfizer Inc.’s Bextra might be even riskier for people with heart disease than rival arthritis drug Vioxx sparked controversy Wednesday at a medical meeting and sent the company’s stock lower.
Dr. Garret FitzGerald, a University of Pennsylvania cardiologist who helped test these types of drugs years ago, told a medical conference that he had reanalyzed some previously published studies on Bextra and concluded that it roughly doubled the risk of heart attacks and strokes the reason Merck & Co. pulled Vioxx off the market in September.
But FitzGerald’s numbers haven’t been published or independently reviewed, and he presented only partial information in a speech rather than a scientific session at the American Heart Association meeting where others could evaluate and critique it.
Pfizer, which besides Bextra also sells a similar painkiller, Celebrex, complained FitzGerald had selectively chosen data that made results appear worse than they were from larger studies of Bextra’s safety.
“Pfizer has shared Bextra clinical results in a timely manner with regulatory authorities both in the United States and worldwide,” said Dr. Joseph Feczko, Pfizer’s president of worldwide development.
FitzGerald said Pfizer and the federal Food and Drug Administration should move more forcefully to determine whether the labels of the whole class of drugs called cox-2 inhibitors need to carry a warning of risks in heart disease patients, and to do larger studies to define their safety for people with arthritis but not heart risks.
He and others have criticized Merck and the FDA for not removing Vioxx before 80 million people took it and the risks became known.
In an opinion piece in the New England Journal of Medicine last month, FitzGerald argued that studies long ago suggest that the problems with Vioxx are a “class effect” shared by other cox-2 inhibitors.
The same mechanism that inhibits inflammation and makes the drugs easier on the stomach than traditional painkillers also blocks a substance that prevents heart problems, FitzGerald believes.
“We have a clear mechanism that applies to this class that explains not only what happened but how it happened,” he said.
In light of the Vioxx withdrawal and his alleged new analysis showing risks of Bextra, “This has shifted the burden of proof onto those who would have to establish that this is not a class effect,” he said.
The Food and Drug Administration plans to convene an advisory committee in February to review the safety of all cox-2 inhibitors.
“We look forward to a scientific and reasoned evaluation in this appropriate setting,” Pfizer’s Feczko said.