The widely publicized study in March 2000 found that patients taking Vioxx were five times more likely to have heart attacks than individuals using the generic medicine naproxen. Merck insisted at the time that this was a result of naproxen's cardioprotective properties and not any defect in Vioxx.
But behind the scenes, company scientists were considering combining Vioxx with another agent to reduce the risk of heart attacks and strokes, according to a document that was mistakenly provided by Merck to plaintiff lawyers as part of the evidence-gathering process in one of the hundreds of Vioxx lawsuits around the country.
That document, a communication between Merck researchers and the company's patent department, stated that the way Vioxx works to reduce pain might also increase cardiovascular problems. They suggested a patent be sought for a combination drug mixing Vioxx with another agent to lessen the risk.
Merck removed Vioxx from the market last September after a later study showed it doubled patients' risk of heart attacks and strokes. Thousand of wrongful death and injury lawsuits have been filed against Merck based on claims that the company hid Vioxx's risks. Analysts estimate the company's liability could reach as high as $18 billion. The first trial is set to begin next month in Angelton, Texas.
The document is potentially among the most damaging to emerge since the drug's sales were suspended because it calls into question the bedrock Merck defense that company officials were convinced of the drug's safety. The desire to reformulate the drug suggests a level of urgency that goes beyond previously disclosed internal e-mails that discussed safety risks.
"The document suggests a level of concern about the drug. The fact that they wanted to patent a different product raises questions — it says something," said Anthony Sebok, a professor at Brooklyn Law School. "Should they have been open about concerns? The failure to be honest is what gets companies (in product liability cases) in trouble."
A copy of the document was provided to The Associated Press on the condition that its source not be identified. A lawyer for Merck declined to discuss the specifics of the document, contending that it was a privileged internal company discussion.
"We continue to believe we acted responsibly," said Merck spokeswoman Cynthia Smith.
Merck shares fell 1 cent to $31.98 in trading Wednesday on the New York Stock Exchange. They have traded in a 52-week range of $25.60 and $48.42 a share.
According to the document, Edward Scolnick, the former head of Merck's research labs, was the first to suggest combining Vioxx with an agent that would block blood platelets from clotting. Such clots can lead to heart attacks and strokes. There are three dates on the document; the first is March 30, 2000.
The document's authors said Vioxx might reduce the production of a substance called prostacyclin, which prevents platelet aggregation. That reduction may alter the ratio of prostacyclin to thromboxane, a substance which can constrict blood vessels and cause clotting. The change may cause increased risk of cardiac and cerebral adverse events, the document said.