Updated

Merck & Co. (MRK) rested its defense Thursday in a closely watched trial aimed at determining whether the company's now-withdrawn arthritis drug Vioxx caused the heart attacks of two New Jersey men. Closing arguments are set for Monday.

The once-popular painkiller was pulled off the market in September 2004 after a study showed it doubled the risk of heart attacks and strokes after 18 months' use. The company faces about 9,650 Vioxx-related suits.

Experts say the case could be a bellwether for thousands of others because it is the first involving plaintiffs who claim long-term use. So far, Merck has won two court cases and lost one.

The latest New Jersey trial, which began March 6, combined the cases of Thomas Cona, 59, of Cherry Hill, and John McDarby, 77, of Park Ridge.

The two blame Vioxx for their heart attacks and say Merck failed to warn consumers about the risks of the drug, which hit the shelves in 1999 and made $2.5 billion in sales in one year alone.

The Whitehouse Station-based company called only five witnesses: two company scientists, two cardiologists and Cona's psychiatrist. The company asserted that it acted responsibly in testing the drug and that the men's pre-existing medical conditions were to blame, not Vioxx.

Lawyers for Cona and McDarby called 14 witnesses, using data from clinical studies of the drug to make the case that the nation's fifth-largest drug maker knew Vioxx caused cardiovascular problems but kept selling it anyway.

Lawyers for Merck and the plaintiffs agreed to preset time limits before the trial began in a bid to keep it moving. Superior Court Judge Carol Higbee's law clerk used chess clocks to keep tabs, pressing a button each time one side's lawyer started or finished questioning a witness.

Both sides rested without using all their allotted time.

"We feel the evidence presented at the trial showed that Merck acted responsibly in testing the drug prior to it going to market and continuing to test it afterward and sharing that information with the FDA and voluntarily withdrawing it," said Chuck Harrell, a spokesman for Merck's legal team.

Lawyers for both sides are to sum up their cases for the six-woman, two-man jury on Monday, after which Higbee will instruct jurors on the law before sending them to deliberate.