In one of the largest prescription drug recalls in U.S. history, worldwide sales of the popular arthritis drug Vioxx were halted today after new data pointed to an increased patient risk for heart attacks and stroke.
With an estimated 2 million people worldwide taking the drug, many arthritis patients today were making panicked calls to their doctors. The drug's maker, pharmaceutical giant Merck & Co., deflected widespread criticism it didn't act soon enough.
But Merck wasn't convinced and stood by the product until today, when it said it was finally able to view comparative data from a clinical trial of what it called a "broad base" of patients, comparing their experience on the medication to that of those who took a placebo.
The clinical trial, testing Vioxx's potential to prevent some cancers, showed the drug at a 25-milligram dose doubled the "risk of a cardiovascular event," the company said.
"Some of us in the medical profession have seen this coming and have been discussing this with patients," said Dr. Calvin Brown, an associate professor of rheumatology at Rush University Medical Center in Chicago. "Doctors phones across the city are ringing off the hook. I don't think Merck hid anything, but they saw the glass as half full. But many of us in the medical profession saw it as half empty."
To be sure, the stakes were high for Merck, which generated more than $2 billion a year in sales from a drug that had been among the top 20 drugs in the U.S. in terms of sales.
Vioxx accounted for 11 percent of the company's $22.5 billion in sales and was needed as the company faces the loss of patent protection for other top sellers like the company's popular cholesterol drug Zocor, which could face generic competition in 2006.
About 2 million people worldwide are currently taking Vioxx and 84 million have taken it since it came on the market in 1999. "It's a disaster for Merck, coming at the worst time," health care analyst Hemant Shah of HKS & Co. in Warren, N.J. told the Associated Press.
Vioxx had been part of drug class of "super aspirin" known as Cox-2 inhibitors, a group of drugs hailed for long-term use because they don't harm the linking of the stomach as do aspirin and ibuprofen, which are as "non-steroidal anti-inflammatories." The drug was primarily used to treat people suffering osteoarthritis, a disease of the joints affecting 20 million Americans.
Given the latest news on Vioxx, consumer groups and some medical professionals believe patients should also stop using the two other most-prescribed Cox-2 inhibitors, Celebrex and Bextra, which are sold by Pfizer Inc.
"Today's announcement by Merck is the latest evidence that this family of drugs, the Cox-2 inhibitors, once referred to as super aspirins are turning out to be super disasters," said Dr. Sidney Wolfe, director of Public Citizen's Health Research Group. "In trying to be a good citizen, Merck ignores its checkered history with Vioxx."
Pfizer and some doctors defended Celebrex and Bextra, saying available data and clinical studies have not shown problems similar to the cardiovascular issues with Vioxx.
Merck said its latest study covered three years and was the first study "of this length ever conducted with a Cox-2 inhibitor," the New Jersey-based drug-maker said in a statement.
In the first 18 months of the study, Merck said there was no difference in the risk of heart attack or stroke in patients taking either Vioxx or a placebo.
"Beginning after 18 months, however, the risk of cardiovascular event did increase among those on Vioxx," said Merck chairman and chief executive officer Raymond Gilmartin. "Accordingly, we are withdrawing Vioxx effective today. We are taking this action because we believe it best serves the interest of patients."
Merck said the company believed it could have continued to market the drug by adding information to its warning label. Further, the Food and Drug Administration believed the risk to patients was minimal but said it had been reviewing earlier studies of Vioxx to see if labeling needed to be updated for possible additional warnings. The FDA said the drug had been labeled, warning of cardiovascular risks.
The FDA said neither Merck nor the agency had calculated the number of heart attacks or strokes that had occurred under Vioxx treatment, and that such a calculation would be impossible.
In the three-year clinical trial, 3.5 percent of the Vioxx patients suffered a heart attack or stroke, while only 1.9 percent of the patients in the placebo group suffered a cardiovascular event, the FDA said.
"We agree with Merck's actions and believe they did the right thing," an FDA official said during a conference call this morning.