Updated

The judge in the second Vioxx trial Thursday denied Merck & Co.'s (MRK) request for a directed verdict in its favor, saying evidence presented by the plaintiff in the product-liability trial justifies a continuation of the court battle.

The decision by New Jersey Superior Court Judge Carol Higbee came on the day Merck began presenting its defense against allegations that its painkiller Vioxx (search) caused the 2001 heart attack of Frederick "Mike" Humeston, a 60-year-old Vietnam War veteran.

In denying Merck's motion, Higbee said lawyers for Humeston had presented "substantial evidence ... if the jury chooses to believe it, that there were misrepresentations and omissions and unconscionable marketing practices by Merck."

The judge five times has denied efforts by Merck attorneys to have a mistrial declared.

Merck pulled Vioxx off the market last year after a clinical trial showed the arthritis and pain medication doubled the incidence of heart attacks with long-term use. The company had heavily marketed the drug since it was introduced in 1999, turning it into a $2.5 billion-a-year blockbuster.

Briggs Morrison, a vice president for Merck Research Labs (search), took the stand as the first defense witness and told the court he had been excited about Vioxx's potential but concerned about how results of a 1997 study comparing the drug to an older painkiller might be interpreted.

Morrison was asked to explain what he meant in an e-mail to Merck colleagues about the study in which he referred to the possibility that Vioxx would be "killed."

He told the court he feared that "people would misinterpret the results and a great drug might end up not making it to market."

Morrison testified that he believed the other drug, naproxen — a common non-steroidal anti-inflammatory drug (search), or NSAID — had heart-protective qualities and that Vioxx by comparison would appear to pose a higher cardiovascular risk.

Humeston's side contends that Merck long knew of the heart risks associated with Vioxx and hid those risks to protect a lucrative revenue source.

Merck's lawyers on Wednesday asked the judge for a directed verdict — a ruling that Humeston's lawyers had failed to prove their case during nearly three weeks of testimony, ending the case in Merck's favor.

But Higbee, in rejecting the motion, said Humeston's lawyers had presented evidence showing Merck knew, or should have known, about the risks of Vioxx but did not adequately communicate them to doctors or to the public.

"The evidence was further presented that there have been studies which showed five times as many heart attacks on Vioxx as naproxen (search), and that these were completed before Mr. Humeston was given his prescription" for Vioxx, the judge said.

She also cited evidence presented that Merck had minimized heart attack risk while highlighting Vioxx's gastrointestinal benefits.

The case is being closely watched following Merck's defeat in August in the first Vioxx lawsuit to go to trial. In that trial, a Texas jury ordered Merck to pay the widow of a Vioxx user $253 million.

Merck has vowed to appeal that verdict, and is facing some 5,000 additional Vioxx product-liability lawsuits.