Colorectal polyps, which are precursors to colon cancer, were known to over produce COX-2.

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The study enrolled 2, 587 patients with a family history of colorectal polyps and assigned them to take either Vioxx or a placebo.

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Merck's (nyse: MRK - news - people ) decision is based on new three-year data from a clinical trial designed to test the effect of Vioxx on preventing colorectal polyps.

FORBES: Merck Withdraws Vioxx