Wed Feb 16, 2005 04:07 PM ET
By Lisa Richwine
GAITHERSBURG, Md. (Reuters) - The heart attack and stroke risks linked to withdrawn arthritis drug Vioxx are an inherent problem for similar pain pills, Vioxx maker Merck & Co. Inc. told advisers to the U.S. Food and Drug Administration on Wednesday.
Merck voluntarily withdrew Vioxx in September after a study showed the drug doubled the risk of heart attack and stroke in patients who took it for at least 18 months.
Since the Vioxx recall, questions have arisen about similar pain pills from Pfizer Inc., Celebrex and Bextra, as well as non-prescription drugs such as naproxen.
The FDA is asking two outside advisory committees if Celebrex and Bextra offer enough benefits to stay on the market, if any pain relievers need stronger warnings and what further research is needed. The advisers are due to meet through Friday.
Studies "strongly suggest" the entire class of drugs called COX-2 inhibitors elevate the chances of cardiovascular problems, Dr. Ned Braunstein, senior director of Merck Research Laboratories, told the panel of FDA advisers.
He added that older, nonprescription pain relievers called non-steroidal anti-inflammatory drugs or NSAIDs, may damage the heart, and said long-term studies were needed to determine the cardiovascular risks of those drugs. NSAIDs include ibuprofen and naproxen.
Merck is trying to win FDA approval to sell another COX-2 inhibitor called Arcoxia in the United States. The drug already is approved in 51 countries, and Merck believes U.S. patients need new alternatives to relieve pain, Merck spokesman Chris Loder said.
The company is testing Arcoxia against an NSAID called diclofenac, Loder said. Arcoxia has not been tested directly against Vioxx to see how it compares, he said.
Pfizer said an analysis of 41 studies concluded Celebrex did not appear to increase the chances of heart attacks or other serious cardiovascular problems.
The risks "may be different in compounds within the class," said Kenneth Verburg, a Pfizer vice president. The Vioxx heart risks appear "distinct," he said.
Pfizer recently added a warning to Bextra about heart problems in bypass patients.
The FDA will work quickly to act on the committee recommendations in the next few weeks, said Dr. Steven Galson, acting director of the FDA's Center for Drug Evaluation and Research. The agency usually follows the advice from its advisory committees, but it is not legally required to do so.
COX-2 inhibitors were designed to relieve pain like NSAIDs while being easier on the stomach. Only Vioxx has been shown to cause fewer serious gastric problems.
Ulcer complications generally afflict about 1 percent to 4 percent of patients who take NSAIDs, Dr. Byron Cryer, a gastroenterologist from the University of Texas, told the panel.
Patients at low risk of stomach problems seemed to suffer fewer stomach problems with COX-2 inhibitors, but no benefit has been seen in people at highest risk, Cryer said.
"A COX-2 may be an attractive option ... but it looks like the target group of interest may not have the anticipated benefit," Cryer said.
Dr. Garret FitzGerald, a pharmacologist at the University of Pennsylvania, said there was evidence the COX-2 drugs raised blood pressure and promoted blood clotting.
"I believe they have value as a class," but the merits of each should be considered separately. To minimize risks, doctors will need to consider each patient's chances of developing heart disease.
Simply reducing doses, as some have suggested, will not eliminate the heart risks because some people will react even to low doses, he said.
(additional reporting by Susan Heavey)