PHOENIX, AZ -- October 21, 1999 -- The cyclooxygenase 2 (COX-2) selective NSAID celecoxib reduced the number and size of colorectal polyps in familial adenomatous polyposis (FAP) in a double-blind, placebo-controlled study presented Wednesday (Oct. 20) at the American College of Gastroenterology meeting, in Phoenix, AZ.
The study, supported by the National Cancer Institute and G. D. Searle & Co., included 77 patients with FAP randomized to either celecoxib (100 mg or 400 mg twice daily) or placebo. Five patients withdrew due to non-compliance or side effects.
At six months, in the group of patients taking 400 mg, there was a reduction in polyp number (28 percent versus 4.5 percent for placebo, p = 0.003), size (4.9 percent versus 0.7 percent for placebo, p = 0.055) and overall colorectal polyp burden (30.7 percent reduction in sum of polyp diameters versus 4.9 percent, p = 0.003). In addition, fewer patients on celecoxib 400 mg had an increase in colorectal polyps over baseline (7 percent) as compared to the placebo group (20 percent).
"These findings in humans support the extensive experimental evidence that cyclooxygenase 2 plays a role in colorectal carcinogenesis," said Dr. Gideon Steinbach, of M.D. Anderson Cancer Center, in Houston, TX.
There was no statistically significant difference in reported side effects between celecoxib and placebo, and no gastric or duodenal ulcers were seen at six months.
A number of important questions remain unanswered. For example, smaller polyps show a more pronounced response, though the data seems to suggest large polyps respond as well. "I believe this study basically demonstrates the efficacy of inhibition of cyclooxygenase 2," Dr. Steinbach said. "Certainly more studies will be needed to fully understand the biologic mechanism."