December 1998: Food and Drug Administration approves Pfizer Inc.'s Celebrex, the first Cox-2 inhibitor, to treat arthritis. Cox-2 drugs, part of the nonsteroidal anti-inflammatory (NSAID) drug class, inhibit the Cox-2 enzyme, which promotes inflammation, but protect users against stomach bleeds and ulcers.
May 1999: FDA approves Merck & Co.'s Vioxx, another Cox-2 inhibitor, for treatment of arthritis and acute pain in adults.
June 2000: Merck gives FDA results of VIGOR study, which shows Vioxx users suffered five times as many heart attacks as users of the older painkiller naproxen, sold under the brand name Aleve. Merck attributes the disparity to naproxen's cardioprotective qualities rather than a defect in Vioxx.
September 2001: Merck receives a warning letter from the FDA about the company's post-VIGOR Vioxx promotional campaign "that minimizes the potentially serious cardiovascular findings" and "misrepresents the safety profile of Vioxx."
November 2001: FDA approves Pfizer's Bextra, also a Cox-2 inhibitor.
April 2002: FDA changes warning label on Vioxx to reflect VIGOR study results showing increased risk of heart attacks and strokes.
May 2002: Carol Ernst sues Merck, alleging Vioxx triggered the May 2001 death of her husband, Robert Ernst, 59.
September 2004: Merck stops long-term APPROVe study, saying it showed Vioxx could double risk of heart attack or stroke if taken for 18 months or longer. Merck voluntarily withdraws Vioxx from the market.
April 7, 2005: Pfizer withdraws Bextra from the market at request of the FDA, which said it carries additional risks of serious, sometimes fatal skin reactions.
July 19, 2005: U.S. District Judge Eldon Fallon schedules the first federal Vioxx trial for Nov. 28, later pushed to Nov. 29.
Aug. 19, 2005: Texas jury finds Merck liable or the death of Robert Ernst, awarding his widow $253.4 million in damages. Merck plans to appeal.
Sept. 14, 2005: The second Vioxx trial begins with opening arguments in New Jersey Superior Court in Atlantic City. Lawyers for Boise, Idaho postal worker Frederick "Mike" Humeston argue his Sept. 2001, heart attack was caused by Vioxx.
Oct. 24, 2005: In its quarterly earnings report, Merck says that as of Sept. 30, it has been named as a defendant in about 6,400 lawsuits over Vioxx. At least several hundred additional lawsuits are filed in October.
Nov. 3, 2005: Atlantic County Superior Court jury rules Merck & Co. not responsible for Humeston's heart attack.
Nov. 28, 2005: Merck announces it will eliminate 7,000 jobs and five production plants and revamp manufacturing in the first phase of an anticipated global reorganization.
Nov. 29, 2005: The third Vioxx trial and the first in federal court begins in Houston rather than its original venue of New Orleans because of hurricane damage. The plaintiff, Evelyn Irvin Plunkett, alleges her husband, Richard "Dicky" Irvin, of St. Augustine, Fla., died in May 2001 after taking Vioxx for about a month, leading to a fatal heart attack. Merck counters that no studies show Vioxx to be dangerous with such short-term use. By this time Merck faces about 7,000 state and federal Vioxx lawsuits.
Dec. 8, 2005: The New England Journal of Medicine publishes an editorial that says Merck concealed heart attacks suffered by three patients in the VIGOR study published in the New England Journal in 2000.
Dec. 12, 2005: A judge in Houston declares a mistrial in the federal lawsuit over Vioxx.
Jan. 25, 2006: A trial over the death of Vioxx user Leonel Garza, 71, gets under way in state court in Rio Grande City, Texas. The trial is ongoing.
Feb. 18, 2006: A jury in federal court in New Orleans takes up the Irvin case in a retrial and finds Merck wasn't responsible in Irvin's death.
April 5, 2006: A jury in Atlantic City, N.J., finds Merck liable for New Jersey resident John McDarby's nonfatal heart attack, but not for one suffered by fellow plaintiff Thomas Cona. The jury ordered that McDarby receive $4.5 million in compensatory damages; the panel said Cona should get $45.