The larger of the two studies -- conducted by researchers at Brigham and Women's Hospital in Boston -- tracked the occurrence of polyps called adenomas in more than 2,000 patients with a prior history of the growths, which are precursors to colon cancer. The patients were split into three groups: The first received placebo, the second received 200 mg of Celebrex twice a day and the third received 400 mg of Celebrex twice daily.
The patients received regular colonoscopies for the next three years, and by the study's end, the researchers found that 60 percent of the placebo patients had developed polyps, while 43 percent of the lower-dose Celebrex recipients developed the growths, and 37.5 percent of the high-dose patients grew polyps. However, the patients taking Celebrex had more than double the rate of serious cardiovascular events compared to the placebo patients. The low-dose patients ran a particularly high risk, with 2.6 times the rate of heart problems over the placebo group.
"The message is that celecoxib (Celebrex) has no role as a chemotherapeutic agent -- in people with adenomas or in people among the general population," writes Dr. Bruce Psaty, a professor of medicine at the University of Washington who co-authored an editorial accompanying the study in the Aug. 31 New England Journal of Medicine. "The risks far exceed the potential benefits."
A second study by University of Texas researchers compared adenoma patients taking a placebo with those taking 400 mg of Celebrex per day, and yielded similar results. The Celebrex patients experienced a 36 percent reduction of adenomas over three years, but their risk of cardiovascular events such as heart attack and heart failure were significantly increased.
Celebrex -- the only cox-2 inhibitor left on the market after Vioxx and Bextra were pulled in 2004 and 2005, respectively -- currently carries the FDA's strongest "black box" warning informing consumers of the heart risks associated with the drug.