Merck & Co. Inc. (MRK) has only started presenting its defense in the second Vioxx trial, but one thing seems clear: The company's lawyers have gotten off to a shaky start.

Already reeling from a big loss in the first Vioxx (search) trial — and harsh criticism of how its legal team handled that case — Merck has a lot riding on the product liability trial under way in its home state of New Jersey.

But experts say the drug company's lawyers may be struggling to regroup after New Jersey Superior Court Judge Carol Higbee on Friday threw out the testimony of Merck's first witness, research executive Briggs Morrison, prompting an unusual shouting match between the judge and a Merck lawyer.

"The witness whose testimony was struck was their first and perhaps their strongest witness, and so that could make it difficult going forward on the case," said Carl Tobias, a law professor at the University of Richmond (search) in Virginia.

"The question is: 'Where does Merck go now?" he said. "Whatever that witness was testifying to, they have to try to replicate that testimony the best they can, and I'm not certain how they will do that."

Merck withdraw the popular painkiller Vioxx from the market last year after studies showed increased heart risk after long-term use. About half of the roughly 5,000 Vioxx cases pending against Merck have been consolidated under Judge Higbee, making her rulings particularly important.

In the New Jersey case, which began in mid-September in an Atlantic City courtroom, plaintiff Frederick Humeston blames Vioxx for his 2001 heart attack.

It's tough to handicap an ongoing trial, but Merck does "have its work cut out for it" in presenting its defense, said John Brenner, a mass tort litigation attorney at law firm McCarter & English in Newark, New Jersey, who is not involved in any Vioxx litigation.

To some lawyers watching the trial, the vehement argument between Merck lawyer Diane Sullivan and the judge on Friday was possibly a calculated move by the defense.

Merck may be hoping to get Higbee removed from the case by trying to portray her as biased in the plaintiffs' favor, these lawyers say. As they sparred, the judge repeatedly ordered Sullivan to stop speaking and at one point threatened to remove the lawyer from the courtroom. Jurors were not present when the argument took place.

"There is such a term, called 'judge baiting' — baiting the judge into losing her cool and her temper," said Steven Wittels, a plaintiff's attorney at law firm Sanford, Wittels & Heisler who has about 100 Vioxx cases pending in New Jersey. "I don't know that they (Merck's lawyers) sit around and think that, but anything is possible."

A member of Merck's defense team, Ted Mayer of law firm Hughes Hubbard and Reed, told Reuters on Monday that the outburst was "absolutely not" planned.

"We were really very surprised by the judge's ruling, which went beyond anything that had been argued about," he said. "Diane Sullivan, like all of us, felt very strongly that the ruling was in error."

Brenner said he doubts Merck intentionally tried to provoke the judge, partly because the stakes in the trial are so high.

Sullivan's outburst likely reflected "an advocate who was caught up in the emotion of the moment," he said.

In the first Vioxx trial in Texas, a jury found the company liable in the death of a Vioxx user and ordered Merck to pay his widow $253 million. Merck's courtroom tactics in that trial were criticized by some legal observers, who said that the company's lawyers likely alienated jurors by tough questioning of the widow for 90 minutes on cross examination.

Experts say the company likely will try to get an emergency appeal before a higher court in an effort to overturn Judge Higbee's ruling barring Morrison's testimony. But chances of success likely are very small, they said.

"If they get an appeal heard, that would be dramatic," said Brenner.

Mayer said the company had not filed an appeal. "We are still considering that," he said.

Merck shares rose $1.21, or 4.75 percent, on the New York Stock Exchange to $26.71. The rebound followed a decline late Friday when several million shares were unloaded in a single transaction, said pharmaceutical analyst Shaojing Tong of Mehta Partners.