Roche and GlaxoSmithKline vaulted a major hurdle yesterday in their bid to get the prescription obesity drug orlistat approved for over-the-counter use in the USA, after a Food and Drug Administration panel lent its support to the switch.

The joint Nonprescription Drugs and Endocrinologic and Metabolic Drugs Advisory Committee voted by 11 to 3 yesterday to recommend approval of orlistat 60mg capsules as an OTC weight-loss medication, to be used three times daily in combination with a low-fat diet, in adults.

If the FDA follows its advice, orlistat would become the only weight-loss product given the seal of approval by the federal agency, lifting it head and shoulders above the plethora of weight-loss products sold as dietary supplements that populate US drugstore shelves. Some of the panellists said that having orlistat available OTC would be positive because it would provide an alternative to these largely-unproven products.

With an estimated two-thirds of American either overweight or obese, OTC orlistat, which will be sold as Alli (pronounced AL-eye) in the USA, has the potential to become a major non-prescription drug brand with blockbuster sales potential.

GSK Consumer Healthcare currently promotes a 120mg prescription formulation of orlistat as Xenical in the USA following an agreement with Roche, and will sell Alli there if it secures FDA approval.

GSK has said it plans to make Alli available at a cost of around $12 to $15 a week, and expects could be used by 5 to 6 million consumers, which could bring in sales of $1.5 billion or more.

The FDA panel discussed the safety and efficacy of the drug, which had been questioned by the agency’s official reviewer in documents posted on its website ahead of the meeting.

Orlistat has gastrointestinal side effects, including anal leakage and gas, can impair the absorption of vitamins and has to be used with caution by diabetics because it can alter the performance of insulin and oral anti-diabetic drugs. But the consensus was that these factors were not serious enough to keep an OTC version off the market.

They were more concerned about orlistat’s interactions with other drugs, such as the anticoagulant warfarin and the immunosuppressant cyclosporine, but overall the panel felt these concerns could be addressed with labelling.