The US Supreme Court Tuesday authorized Merck shareholders to sue the pharmaceutical giant for fraud for "knowingly" misrespresenting the risk of heart attacks from the use of the anti-inflammatory drug Vioxx.
The nation's top judges ruled unanimously in the case, which involves millions of dollars in damages.
The company "knowingly misrepresented the risks of heart attacks accompanying the use of Merck's pain killer drug Vioxx, leading to economic losses when the risks later became apparent," the court ruled.
Merck voluntarily withdrew Vioxx from sale in September 2004 after a company internal study in 2001 showed the drug doubled the risks of heart attack in patients who took it for 18 months or longer.
Internal analyses dating from April 2001 of pooled data from the two trials "identified a significant three-fold increase in total mortality," a 2008 study found.
The ruling Tuesday marks the latest blow for Vioxx, which in 2007 was the focus of a 4.85-billion-dollar legal settlement.
The deal, which allowed Merck to settle more than 95 percent of lawsuits over the drug, marked a major reversal for the company, which had earlier said it would fight more than 27,000 lawsuits.
The Supreme Court said the "judgment of the Court of Appeals is affirmed" in that shareholders were misled about the risk, saying "we need only to conclude that prior to November 6, 2001, the plaintiffs did not discover and Merck has not shown that a reasonably diligent plaintiff would have discovered (the facts constituting the violation)."