FDA Staff Concerned Over Safety of OTC Version of XenicalJan 22, 2006
While an FDA advisory panel of outside experts is scheduled to meet on Monday to discuss the petition by GlaxoSmithKline (GSK) to market a half-dose over-the-counter (OTC) version of the weight-loss drug Xenical, FDA staffers have expressed reservations about the product’s safety with respect to some patients.
Approval of Xenical (orlistat) by the FDA would be a first for OTC weight-loss drugs. It would also mean enormous potential revenue for pharmaceutical giant GSK (No. 2 in the world), which purchased the U.S. rights for OTC Xenical from Roche Holding AG (No. 9 in the world) in 2005.
While the FDA staffers acknowledged the OTC version of the drug helped more patients lose weight after six months than those on placebo, they were concerned that early data showed some diabetics and others for whom the drug would be contraindicated did not understand the risk to them after reading the product label. In addition, the staff noted that once the drug is discontinued, users regained the weight they had lost.
Thus, the staff wrote: "Preliminary evidence suggests that nonprescription labeling may not adequately direct the safe use of orlistat (Xenical)."
The mechanism that makes the drug effective is that it helps prevent fat from being absorbed by the body. This, however, can cause some unpleasant side-effects like excess gas and oily discharge.
GSK proposes to market Xenical with a behavioral support program and in-pack materials that will serve as a weight loss program for Americans seeking treatment for obesity, which has reached record rates in the U.S. The company suggests the gastrointestinal side-effects could be managed by cutting down on the amount of dietary fat.
The unpleasant and unpredictable side effects are regarded as the reason why worldwide sales of prescription strength Xenical are relatively low (some $460 million in 2004).
The other leading prescription weight-loss drug is Abbott Laboratories Inc’s Meridia, an appetite suppressant that is the subject of widespread safety concerns among consumer watchdog groups and pharmaceutical experts who claim that the drug is linked to side effects such as rapid heart rate, increased blood pressure, heart disease, stroke, seizure, and mental impairments.
Both form of the drug must be taken three times each day. The cost is about $1 to $2 per pill for the prescription version ($90 to $180 a month) and about 60 cents per pill for the OTC version ($54 a month).
According to the concerned FDA staffers, only 35% of diabetics on medication correctly recognized they should not take Xenical after reading the product label. Only 50% of the patients on prescription blood-thinners (warfarin) or cyclosporine (to prevent organ rejection) understood that they too should not take Xenical.
Xenical can also lead to hepatitis, gallstones, and kidney stones, although the cause of this is still unclear.