Lawyers for Merck & Co. told the Supreme Court Monday that investors waited too late and didn't do all of the necessary investigations to sue the drug maker over whether it properly warned about the risks of its blockbuster painkiller Vioxx.

Whether the high court agrees with the drug maker will help clarify the legal standards for determining exactly when the clock starts running for the two-year window to sue a company accused of defrauding investors.

Merck wants the high court to overturn a decision by the 3rd U.S. Circuit Court of Appeals that will let proceed a class-action securities lawsuit related to the tens of billions of dollars in shareholder value lost overnight after Merck pulled Vioxx off the market.

The Whitehouse Station, New Jersey-based company withdrew the drug from the market on Sept. 30, 2004, because it doubled the risks of heart attack, stroke and death.

Investors had accused Merck of providing misleading information or omitting information about the risks of Vioxx. After a widely publicized study comparing Vioxx to naproxen, another pain reliever, found about five times more heart attacks in the patient group taking Vioxx, Merck officials argued repeatedly that was because naproxen protected the heart.