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Celebrex Cuts Pre-cancerous Colon Growths in Study

Posted on: Monday, 3 April 2006, 17:35 CDT

By Lisa Richwine

WASHINGTON (Reuters) - High doses of Pfizer Inc.'s arthritis pill Celebrex reduced the number of pre-cancerous growths in the colon in two large studies but ongoing concerns about heart risks make it too soon to recommend that use, researchers said on Monday.

More study is needed to determine if taking Celebrex daily for years makes sense for some patients who face a high risk of developing colon cancer, the scientists said.

"We are very confident of the efficacy results. The problem is that we cannot be so confident of the toxicity results," said Dr. Monica Bertagnolli, a Harvard researcher who worked on one of the studies.

Celebrex, known generically as celecoxib, is in the same family of drugs as Merck & Co. Inc.'s Vioxx, which was pulled from the market in 2004 because of a link to heart attacks and strokes. Both drugs inhibit the COX-2 enzyme involved in inflammation.

Shortly after the Vioxx withdrawal, Pfizer said preliminary analyses of a cancer-prevention study showed Celebrex more than doubled heart attack risk. At the time, the company said another trial to reduce colon polyps did not show an increase in heart problems.

Additional details, including the effectiveness results, from those studies were released on Monday at a meeting of the American Association for Cancer Research.

A new, broader analysis "found more cardiovascular events with Celebrex compared to placebo" in both trials, Pfizer said in a statement. "These results are consistent with the current warnings on cardiovascular risk in the Celebrex label," the company said.

Researchers said Celebrex clearly worked to reduce the number of benign growths called adenomas in the colon.

One study of 2,035 patients tested 200- and 400-milligram doses of Celebrex or a placebo taken twice a day for three years. All patients started taking the pills after having benign growths removed from the colon and were considered at risk of developing colon cancer.

The number of patients who had one or more adenomas in the colon three years later was 45 percent lower among Celebrex patients, researchers said. The study was funded by Pfizer and the National Cancer Institute.

In a second study funded by Pfizer, colon polyps were detected in 34 percent of patients who took 400-milligrams of Celebrex once a day, compared with 50 percent of placebo patients.

The number of cardiovascular problems was small, making it difficult to tell who is at risk for such complications, researchers said. More study may yield clues as to who is most likely to suffer heart problems while taking Celebrex and who might benefit most from a cancer-prevention use.

"I don't think there is a subset of patients we can recommend celecoxib use in today (for reducing polyps). Nonetheless, the degree of efficacy suggests we really do need to keep looking," said Dr. Ernie Hawk, a National Cancer Institute researcher.

In addition to its widespread use for treating arthritis pain, Celebrex is approved for treating patients with a rare hereditary condition in which hundreds or thousands of polyps form on the colon and eventually turn cancerous.

The drug carries a warning that it and other pain relievers known as non-steroidal anti-inflammatory drugs may increase the chances of developing possibly fatal cardiovascular problems.

Pfizer is funding a separate study designed to determine the heart risks of Celebrex compared to other pain relievers.

Scientists believe COX-2 inhibitors may help ward off certain cancers because the diseases are linked to inflammation. COX-2 is one component of inflammation.

Shares of New York-based Pfizer gained 20 cents to close at $25.12 on the New York Stock Exchange.

(Additional reporting by Deena Beasley and Julie Steenhuysen)

Source: REUTERS

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