NEW YORK (CNNMoney.com) -- The plaintiff in the next scheduled Vioxx case has dropped her suit against Merck, the drug company said.

Sharon Rigby, who had accused Merck's painkiller Vioxx of causing her heart attack, dropped out just two weeks before the proceedings in her case were scheduled to begin in Texas, Merck said.

Merck (down $0.16 to $45.54, Charts), the No. 4 U.S. drugmaker behind Pfizer (down $0.57 to $27.16, Charts), Johnson & Johnson (down $0.46 to $68.64, Charts) and Abbott Laboratories (down $0.93 to $47.90, Charts), still has plenty of work to do defend its former product Vioxx from a tally of 23,800 lawsuit cases. Former Vioxx patients, who took the drug as an anti-inflammatory for their arthritis, and their suriviving family members have accused the drug of causing heart attacks and strokes. They have also accused Merck of misrepresenting the risks of the drug.

Merck, based in Whitehouse Station, N.J., has consistently denied accusations of wrongdoing and said its drug didn't kill anyone. Company executives said they will not settle and have vowed to fight all cases one by one, if necessary.

Vioxx sales were $2.5 billion annually before Merck pulled the drug off the market on Sept. 30, 2004 after a company-funded study showed that the drug increased risk of heart attack.

Merck legal spokesman Kent Jarrell attributed the recent surge in Vioxx lawsuit filings to the recent expiration of a two-year statute of limitations on personal injury and wrongful death cases in at least 22 states.

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