People at high risk for colon cancer may slow or prevent development of the disease by taking the painkiller Celebrex, two large studies suggest. But some doctors caution an increased risk of heart attacks and strokes from the medicine overshadows its potential benefits for cancer prevention.
Two studies published in the New England Journal of Medicine this week show that Pfizer Inc.'s Celebrex, most commonly taken to relieve arthritis pain, reduced the recurrence of polyps, small growths in the colon that can become cancerous over time.
In one study, 61% of patients on placebo developed new polyps over three years compared with 43% on 200 milligrams of Celebrex twice a day. For people taking 400 milligrams of Celebrex twice a day, the incidence of new polyps was 38%. All the patients had polyps of the colon removed previously, a risk factor for colon cancer. But patients taking the placebo had an incidence of 1% for serious cardiovascular events, such as heart attack, compared with 2.6% for the lower dose of Celebrex and 3.4% for the higher dose.
A second study found that 34% of people taking 400 milligrams of Celebrex once a day developed new polyps over three years compared with 49% of patients taking a placebo. Some 2.5% of patients taking Celebrex experienced serious cardiovascular trouble compared with 1.9% in the placebo group. A common dose of the drug for arthritis pain is 200 milligrams a day.
Despite the intriguing results, an editorial accompanying the two studies concluded that due mainly to the cardiovascular risks Celebrex, or celecoxib generically, has "no role" in preventing cancer in the general population or people who don't have profound hereditary risks for colon cancer. If polyps are found early by colonoscopy, they can be removed, preventing cancer.
Still, the inhibition of polyps "was proof of principle" that a medicine could make a difference in the course of the disease, said John Saltzman, a researcher on one of the trials, called APC, and director of endoscopy at Brigham and Women's Hospital, Boston. While the APC investigators also concluded that Celebrex isn't appropriate for widespread use to prevent colon cancer, Dr. Saltzman said he would consider Celebrex for patients with a very high risk for polyps and a low risk of cardiovascular disease.
Michael Osborne, president of the Strang Cancer Prevention Center in New York, said the next step is to better characterize the risk factors to identify patients who might benefit without undue danger.
Simon Lowry, a medical director for Celebrex at Pfizer, described the cancer results as "encouraging" but said, "We do not recommend Celebrex in treating and preventing cancer." But for arthritis sufferers, Dr. Lowry added, the drug is "an important treatment option."
The first study was funded by the federal National Cancer Institute and Pfizer. The study was stopped in December 2004 after a safety review found an increase in serious cardiovascular problems in the group of patients taking Celebrex compared with the placebo group. The second study was financed by Pfizer and was halted after the safety findings in the first study.
An in-depth review of safety data in the first, or APC, trial was done after a similar trial of Merck & Co.'s Vioxx for cancer prevention revealed an increased cardiovascular risk that led the company to take the drug off the market.
More about Celebrex current clinical trials at Drug Pipeline Database
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