GlaxoSmithKline’s proposal to switch obesity drug Xenical (orlistat) from prescription to over-the-counter status will go up against a US Food and Drug Administration advisory committee next month.

GSK filed for approval to sell Xenical OTC in June, after acquiring non-prescription marketing rights to the drug from Roche in July 2004 for $100 million dollars. Roche retained all rights to market Xenical as a prescription drug in the US and all rights (prescription and non-prescription) outside this market.

Discussion at the joint advisory committee meeting on January 23 may focus on the potential use or misuse of the drug’s OTC version in adolescent populations, according to a report on fdaadvisorycommittee.com. Although Xenical can be prescribed to adolescents, GSK’s proposal recommends that those under the age of 18 seek the advice of their physician.

OTC approval would give the Xenical franchise a needed boost. The product has failed to achieve its once prophesied blockbuster status, but nevertheless has seen annual sales peak in the 600 million Swiss franc region. But Xenical experienced flagging sales last year - down 2% to 593 million francs, and this followed a 13% dip a year earlier.

Nevertheless, prospects for the drug have been improved by having its label expanded to include a benefit on glucose intolerance, as well as approval for adolescent obesity.

GSK has said it expects Xenical to be available OTC by mid-2006.