The nine-member jury on Thursday decided that Merck provided adequate warning to doctors about health risks associated with its withdrawn painkiller and did not commit consumer fraud in marketing the drug.
The jury also found the drug maker did not misrepresent, suppress or conceal information about increased risks of heart attack and stroke from the painkiller.
The verdict in the seven-week trial in New Jersey may help Merck defend itself against at least 2,700 other cases in the state and some 6,400 cases nationwide.
Last August, in the first Vioxx case to go to trial, a Texas jury found Merck liable for the death of a 59-year-old Vioxx user and awarded his widow US$253 million in damages. Merck is appealing that decision.
Despite the latest victory the company faces a laborious defence in courtrooms nationwide.
"We recognise that this litigation is not over, that there are many more cases to go," Merck general counsel Kenneth Frazier said.
Heart attack claim
The latest case was filed in New Jersey Superior Court by Frederick Humeston, 60, an Idaho postal worker and Vietnam War veteran, who claimed Vioxx caused his mild heart attack in 2001 after less than two months of intermittent use.
He filed his lawsuit in mid-2003, a year before Merck recalled Vioxx due to cardiovascular safety concerns.
His lawyers accused Merck of hiding for years evidence that Vioxx caused increased heart risks in order to protect huge profits.
But after more than a day of deliberation, the jurors decided 8-1 that Merck scientists in 2001 did not believe that Vioxx could increase risks of heart attack and stroke.
They found that the company had no obligation to warn physicians, including the doctor who prescribed Vioxx to Mr Humeston for knee pain caused by a shrapnel wound.
The drugmaker said it pulled the US$2.5 billion-a-year drug from the market in September 2004 as soon as it had clear data showing that long-term Vioxx use doubled the risk of heart attacks and strokes.
The jury of six women and three men, voting 9-0, also rejected a consumer fraud charge.
"He only took it for two months, and he was taking a lot of other stuff," one juror, Nellie Stetzer, said.
The study that led to the Vioxx withdrawal found increased heart risk only after 18 months of continuous use of the drug.
Vickie Heintz, a 40-year-old juror from New Jersey, said Mr Humeston had "way too many health issues," to win his case.
"If you looked at his medical records over the past 20 years it was riddled with a history of medications and health problems. Stress absolutely played a role," Ms Heintz said.
Merck's lawyers argued that the postal worker was under tremendous job-related stress at the time of his heart attack.
"Frederick Humeston would have suffered a heart attack when he did, whether he was taking Vioxx or not," said Jim Fitzpatrick, one of Merck's attorneys.
The case was being closely watched as a potential indicator of future Vioxx litigation.
"I wish to impart to other plaintiffs, do not let this deter you because Vioxx is a bad product," Mr Humeston told reporters after the verdict.
Judge Carol Higbee, who presided over the Humeston case, is expected to oversee the bulk of the New Jersey cases.
The first federal Vioxx case is scheduled to go to trial on November 28.
"There will be other Vioxx trials and we will vigorously defend them one by one over the coming years," Merck’s general counsel Kenneth Frazier said.
Merck has set aside US$675 million to fight the Vioxx lawsuits.
Analysts say Merck could eventually have to pay anywhere from US$5 billion to US$50 billion to cover potential liability from the growing wave of lawsuits.