Celebrex May Play Role in Colon Cancer Prevention
Oct. 18, 1999 (Phoenix) -- A powerful new arthritis drug, Celebrex (celecoxib), may hold the key to preventing colon cancer. Cancer experts are impressed because treatment with the drug appears to reduce the number of polyps in patients with familial adenomatous polyposis.
Familial adenomatous polyposis is a rare condition that runs in certain families. It accounts for about 1% of all colon cancers. However, multiple colon polyps begin to arise in adolescence, and the risk of developing colon cancer at some point during an individual's lifetime is nearly 100%.
A new study shows that taking 400 mg of Celebrex twice a day for six months reduced the number of polyps in patients with the inherited disease by 28%, says Gideon Steinbach, MD, of the M.D. Anderson Cancer Center in Houston. Steinbach says that the drug also reduced "polyp burden" by 30%. Polyp burden is a term used to describe the overall impact of the disease: number of polyps, size of polyps, and area of the colon affected by the polyps. He plans to present the study here Wednesday at the 64th annual meeting of the American College of Gastroenterology.
The drug blocks cells from producing a substance called Cox-2, which was discovered just a few years ago. Cox-2 is an enzyme involved in the production of inflammation, which leads to the pain seen in disorders such as arthritis. Celebrex was designed to specifically target and block Cv-2, reducing inflammation. For some time researchers have been reporting that aspirin and other drugs like it appear to reduce the risk of colon cancer. These drugs are called nonsteroidal anti-inflammatory drugs, or NSAIDs. Whereas Celebrex and other Cox-2 inhibitors effectively reduce inflammation, the Cox-2 inhibitors don't cause the stomach problems associated with aspirin and other NSAIDs.
Steinbach tells WebMD that this study of 77 patients with familial adenomatous polyposis "is more than three-times larger than any of the previous trials ... for the first time it demonstrated the efficacy of Cox-2 inhibition in reducing or controlling colorectal adenomas."
Steinbach, along with other researchers from the National Cancer Institute and St. Mark's Hospital, Middlesex, England, randomized patients to receive either 100 mg of Celebrex twice a day, 400 mg of Celebrex twice a day, or a placebo. "There may have been a slight response or trend toward response at 100 mg, but it was not significant compared to placebo," Steinbach says.
Steinbach says that all of the patients in the study already had evidence of polyps associated with the disorder. He says that he cannot speculate on a preventive role for Cox-2 inhibitors among persons who have the genetic disorder but show no symptoms. "This [study] is a first step. It would require further study to assess a Cox-2 inhibitor for prevention," he says.
The tumors seen in people with familial adenomatous polyposis develop similarly to people who develop colon cancer but do not have the genetic disorder, according to Steinbach. "That's why there is a lot of work with this disorder, because it is very likely that drugs effective in familial adenomatous polyposis could be used in prevention of sporadic colon cancer," he says.
Last month, the pharmaceutical firm Searle, maker of Celebrex, obtained priority review status from the FDA for its application asking that doctors be allowed to prescribe Celebrex for familial adenomatous polyposis. The FDA is expected to rule on that application by next spring.
Partial funding for Steinbach's study came from Searle, although he says that this study was not submitted as a part of that FDA application.