The investors are seeking billions of dollars in damages from Merck. A federal trial judge in New Jersey said the investors' lawsuits weren't filed within the allowable two-year time frame and dismissed them as untimely. An appeals court, however, reinstated the lawsuits last year.
The Supreme Court, in a short one-line order, agreed to consider Merck's appeal of the decision to allow the lawsuits to proceed.
Investors filed the first of several securities lawsuits against Merck in November 2003, alleging the drug maker misled them by downplaying the significance of clinical-trial results that appeared to show that patients taking Vioxx faced an increased risk of heart attack.
The investors said this alleged deception cause them to pay inflated prices for Merck's stock.
The central issue before the Supreme Court focuses on when investors should have known that there was a possible Vioxx fraud.
The trial judge ruled that investors missed their two-year window to sue because "storm warnings" about possible Vioxx fraud were public by October 2001.
The 3rd U.S. Circuit Court of Appeals in Philadelphia, however, disagreed and reinstated the lawsuits. The appeals court, on a 2-1 vote, said investors didn't have enough concrete evidence to suspect a possible Vioxx fraud until 2003.
Merck said in a statement that it "properly informed the FDA and the scientific community" about Vioxx-related data as it emerged.
The drug maker said the trial judge was correct to throw out the lawsuits because "the intense public discussion of data surrounding Vioxx had put investors on inquiry notice of the relevant issues long before Merck became aware of and announced the new scientific information that led to the voluntary withdrawal."
Sean Coffey, co-lead attorney for the plaintiffs, said he was confident the Supreme Court would side with the investors.
Coffey said Merck argued that ample evidence existed in 2001 for investors to bring Vioxx fraud lawsuits, but then also claimed that there's not evidence even now to show that the company acted fraudulently.
"They're arguing out of both sides of their mouth," he said.