Pharmaceutical giant Merck & Co. said Thursday it will halt worldwide sales of its popular arthritis drug Vioxx in the wake of new data showing increased risk of heart attacks and stroke.
Some 2 million people worldwide are taking the drug, making Merck's move one of the largest prescription drug withdrawals in history. Since the arthritis medicine was introduced in 1999, roughly 84 million prescriptions have been written for it.
"We are taking this action because we believe it best serves the interests of patients," said Raymond Gilmartin, chairman and chief executive of Merck. "Given the availability of alternative therapies and the questions raised by the data, we concluded that a voluntary withdrawal is the responsible course to take."
Sales of Vioxx already had been deteriorating during the last two years following several observational studies and analysis of medical claims that showed the drug caused cardiovascular problems.
But Merck was not convinced. It stood by the product until Thursday, when it said it was 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 those who took a placebo.
That trial, which looked at whether Vioxx could prevent some cancers, showed that 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. "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."
The stakes were high for Merck, which generated more than $2 billion a year in sales from a drug that has been among the top 20 medications in the U.S. in terms of sales.
Vioxx accounted for 11 percent of Merck's $22.5 billion in sales and was needed as the drugmaker faces the loss of patent protection for other top-sellers, such as the company's popular cholesterol drug Zocor, which could face generic competition in 2006.
On news of the product withdrawal, Merck shares plunged $12.07, or 27 percent, to $33 in heavy trading on the New York Stock Exchange.
Earnings to fall
Merck said the Vioxx move will trim 50 to 60 cents a share from its earnings for the rest of the year because of foregone sales, write-offs of inventory held by Merck, customer returns of product and related costs of the withdrawal.
"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 a "super-aspirin" drug class known as cox-2 inhibitors, a group of medications hailed for longer-term use because they do not harm the lining of the stomach as do aspirin and ibuprofen, which are known as "non-steroidal anti-inflammatories."
The drug was primarily used to treat people suffering from osteoarthritis, a disease of the joints affecting more than 20 million Americans.
Given the latest news on Vioxx, at least one consumer group said 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 more like super-disasters," said Dr. Sidney Wolfe, Director of Public Citizen's Health Research Group.
Drugs have defenders
But 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.