Expert believes Vioxx causes heart attacks, and can trigger an event in a month

Lawyers for Merck & Co. were expected to cross examine an expert witness on Friday over his belief that the company's former blockbuster pain drug Vioxx can cause heart attacks and can trigger an event in less than a month.

Wayne Ray, who studies the risks and benefits of drugs, told jurors on Thursday that he reached his conclusions after analyzing numerous studies, including the one that pushed Merck to removed Vioxx from the market last year after tests showed it doubled patients risk of heart attacks after 18 months.

Jurors will be asked to decide if Vioxx contributed to the fatal heart attack Richard "Dicky" Irvin suffered in May 2001. The 53-year old manager of a seafood distributor had been taking the drug for about a month to alleviate back pain when his colleagues found him dead at his desk. Irvin's widow, Evelyn Irvin Plunkett, is suing Merck, which has scored a loss in Texas and a win on its home turf of New Jersey in the first two state-level Vioxx cases.

Merck faces about 7,000 state and federal lawsuits, and analysts have estimated its liability could reach $50 billion (Ђ42.57 billion). The brief duration of Irvin's Vioxx use is expected to be a big issue in the case, with Merck arguing that the drug only showed signs of problems after 18 months.

Ray said he examined two epidemiological studies of patients taking Vioxx for 30 days or less. One found the drug increased patients likelihood of having a heart attack one and a half times while the other found an elevated risk of nearly threefold.

Epidemiological studies are typically retrospective examinations of existing data. While they are considered useful because they examine how drugs act in the greater population, blinded clinical trials that directly compare a drug to a placebo in a controlled setting are considered the gold standard in the pharmaceutical industry.

Ray used both kinds of studies in his overall analysis. When he just examined clinical trials, Ray found that Vioxx increased the risk from more than two times to just under three times. He said the odds were one in a million that the results were due to chance.

Ray also disputed Merck's assertion that there was increased risk after 18 months; he said data showed risk becomes apparent at six months. Earlier in the day, Dr. Thomas Baldwin testified that Irvin was at low risk for a heart attack and his blocked artery didn't need invasive treatment.

The Kansas City-based cardiologist said Irvin lacked many of the factors associated with heart attacks, such as high blood pressure and diabetes, the AP reports. Plunkett alleges that Vioxx _ which inhibits an enzyme that promotes inflammation_ led to the clot formation because it thins the blood. Merck says that plaque, or fatty deposits in artery walls, ruptured and caused the clot that lead to Irvin's death.

Baldwin said the clog in the major artery wasn't significant enough to treat. According to testimony, the artery was 60 percent clogged, but Baldwin said the condition appears worse after death so it probably wasn't as constricted as believed. A.M.