OTC weight drug seen unsafe for some -- US FDA staff

By Susan Heavey

WASHINGTON (Reuters) - A proposed over-the-counter version of the diet drug Xenical may pose safety problems for some patients, U.S. Food and Drug Administration staff said in documents released on Friday.

An FDA advisory panel of outside experts is due to meet on Monday to consider GlaxoSmithKline's petition to sell a half-dose version of Xenical without a prescription.

In documents released ahead of the advisory panel, FDA staff reviewers said early data showed some diabetics and other patients who are not supposed to take the drug did not understand the risk after reading the label.

"Preliminary evidence suggests that nonprescription labeling may not adequately direct the safe use of orlistat (Xenical)," the staff wrote.

Still, the FDA reviewers said the proposed version of Xenical helped more patients lose weight after six months than those taking a placebo.

The FDA usually follows the advice of its advisory panels.

Glaxo acquired the U.S. rights for nonprescription Xenical from Roche Holding AG last year.

Known generically as orlistat, Xenical helps prevent fat from being absorbed by the body but can cause excess gas and oily discharge.

It is one of two main prescription obesity drugs on the U.S market for long-term use. Its rival, Abbott Laboratories Inc's Meridia, suppresses appetite.

Glaxo said allowing over-the-counter sales would help fight soaring rates of obesity in the United States, making it easier for overweight Americans to seek treatment.

"OTC orlistat, in conjunction with the behavioral support program and in-pack materials, will serve as a weight loss program," the British drug maker said in documents also released on Friday.

But FDA staff worried that people may not correctly determine whether non-prescription Xenical was safe for them.

Among diabetics taking medication for their condition, 35 percent correctly recognized after reading the label that they should not take Xenical. Half of patients taking blood thinner warfarin or cyclosporine, which prevents organ rejection, realized they should not take the drug, the staff said.

Xenical can also lead to hepatitis, gallstones and kidney stones. FDA staff said it was unclear how Xenical causes such problems.

Glaxo said gastrointestinal problems could be managed by eating less fat.

Shares of Glaxo were down 50 cents, or about one percent, to $50.25 in mid-afternoon trading on the New York Stock Exchange. In London, Glaxo shares closed down less than one percent.

The documents were posted on the FDA's Web site at http://www.fda.gov/ohrms/dockets/ac/06/briefing/2006-4201B1-index-with-disclaimer.htm