Vioxx Timeline: 1998-2005

On Friday, Merck(MRK) lost its first Vioxx trial and promptly said it would appeal the Texas state court jury verdict. The company is facing at least 4,100 individual personal injury suits, a host of class-action lawsuits and litigation claiming Merck's handling of Vioxx violated securities laws as well as laws governing retirement plans. And that's only the U.S. cases. Here's a look at how Merck and Vioxx wound up in court.

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November 1998: Merck submits an application to the Food and Drug Administration seeking approval for the Cox-2 inhibitor drug Vioxx as a treatment for osteoarthritis, on the basis of clinical trials involving 5,400 patients. Merck says rates of cardiovascular risk were "similar" among patients taking Vioxx, placebo or other pain relievers.

January 1999: Merck begins the Vigor trial designed to test gastrointestinal impact of Vioxx. A month later, Merck begins the first of two tests to determine if Vioxx has a beneficial effect on Alzheimer's disease patients.

May 1999: The FDA approves Vioxx.

February 2000: Merck starts the Approve trial designed to ascertain if Vioxx reduces certain colon polyps.

March 2000: Merck receives preliminary results of Vigor trial, suggesting higher risk of cardiovascular problems among patients taking Vioxx vs. patients taking the pain reliever naproxen. Merck later speculates that the difference is caused by the heart-protective effect of naproxen rather than the heart-risk effect of Vioxx.

March 2000: Merck announces preliminary results of Vigor trial and submits data to the FDA. Later in the year, Vigor trial results are published in the New England Journal of Medicine.

February 2001: FDA advisory committee holds a hearing on Vigor trials.

April 2002: After lengthy discussions with the FDA, Merck revises the Vioxx label to include precautions about cardiovascular risk cited in the Vigor trial. Critics would later allege that Merck showed a lack of urgency in changing the label, arguing that this was an example of Merck having known the drug could cause heart problems.