Apr 11 2006
A consumer watchdog group in the U.S., Public Citizen, has petitioned the U.S. Food and Drug Administration (FDA) to withdraw the prescription diet drug Xenical (orlistat) from the market; the group also want the FDA to refuse approval for the weight-loss pill to be made widely available over the counter.
Public Citizen's petition is based on findings from the pharmacology review of Roche's own data and a recent independent confirmation that Xenical causes pre-cancer in the colon of rats.
Public Citizen has an excellent track record of identifying dangerous drugs well before federal regulators take action to ban or put warnings on these drugs.
Public Citizen alerted consumers about the dangers of Vioxx, Ephedra, Bextra, Rezulin, Baycol, Propulsid and many other drugs years before the drugs were pulled from the market.
Last week the FDA granted drug company GlaxoSmithKline conditional approval for the drug to be sold without a prescription as long as it met certain undisclosed criteria.
Roche and GlaxoSmithKline have a promotion agreement for Xenical in the US.
Dr. Sidney Wolfe, director of Public Citizen's Health Research Group, says the failure to ban the prescription version of the drug, or to make it much more widely available by allowing OTC sales is a decision that is likely to increase the risks of cancer as recent data has linked the drug to precancerous colon lesions in animal studies.
The advocacy group says a December 2005 study confirmed earlier company data showing Xenical can cause abnormal cell growth in the lining of the colon.
Experts widely recognize the lesions as an early indicator of cancer.
The study which was published in the journal Cancer Letters, found "a significant increase" of colon lesions in rats given Xenical regardless of whether they were on high-fat or standard diets.
Xenical comes in 120-milligram capsules to be taken three times a day with meals. The proposed nonprescription version, called Alli, comes in 60 milligram tablets with one to two taken with meals.
Xenical works by preventing fat from being absorbed by the body but can cause excess gas, oily discharge and other gastrointestinal problems.
Public Citizen also said its review of reported side effects after Xenical hit the market in 1999 found 28 cases of breast cancer in patients taking Xenical through June 2005.
A review of its rival, Abbott's appetite suppressant Meridia, found two breast cancer cases between November 1997 and June 2005.
Public Citizen says the FDA was aware of the breast cancer risk as well as possible colon lesions when it initially considered Xenical, but the agency chose to rely on the company's analysis.
Although the link between fat and cancer is unclear, some studies have shown a higher risk in people who are overweight or obese and other studies have shown no change in risk despite lower fat diets.
Some early data did apparently show that Xenical can help curb fatty acids and possibly limit tumor growth, admits Public Citizen and removing it from the market would not stop future research.
The 12-page petition says "The FDA should not allow a drug … to remain on the market for the long-term treatment of a non-lethal condition when it combines so little efficacy coupled with a still unresolved potential to cause breast and colon cancer".