Swiss researchers reported Thursday in an international medical journal that evidence was clear and overwhelming in 2000 that Vioxx doubled the rate of heart attacks, and Merck & Co. Inc. should have withdrawn the drug four years ago.
The analysis, by Peter Juni and colleagues at the University of Berne, looked at results from 18 Vioxx studies, all sponsored by Merck, that showed that 41 patients out of about 11,000 Vioxx users by late 2000 had suffered heart attacks, twice the rate of those receiving a placebo or other painkillers.
The study, funded by the Swiss National Science Foundation, analyzed 18 randomized controlled Vioxx trials and 11 related observational studies. The results were published online by the British journal The Lancet. The data was based on data obtained primarily from the U.S. Food and Drug Administra-tion.
When Merck withdrew Vioxx Sept. 30, after a company-sponsored study found a doubling of the risk of heart attack and stroke in users after 18 months, Merck said the data was “unexpected.”
Merck said in a press release Thursday that it has been “vigilant in monitoring and disclosing the cardiovascular safety of Vioxx,” and “we absolutely disagree with any implication to the contrary.”
Prudential Equity Group analyst Tim Anderson said that the Lancet’s report “plays into the hands of plaintiffs’ attorneys” and “has the ability to bolster their case against the company.” However, Anderson said lawyers suing Merck must prove two things: The company was negligent and knew about the Vioxx risks, and that the drug played a role in causing heart attacks or strokes.
Proving causation that Vioxx caused people’s heart problems will be “much harder to achieve,” Anderson said. “We do not think at this time, at least, that the company’s ultimate liability will sum to fen-phen-like proportions,” referring to the $16.6 billion Wyeth has set aside to pay for liability from its recalled diet drugs.
David Risinger, an analyst at Merrill Lynch, estimates Merck’s legal costs could reach $4 billion to $18 billion, including $2.5 billion to $15.3 billion to cover “serious” cardiovascular claims.
Merck said recently at least 300 lawsuits have been filed by people who took Vioxx. More than 20 million Americans have taken Vioxx since it was introduced in 1999. With annual sales of $2.5 billion, Vioxx last year accounted for about 11 percent of Merck’s revenue.