Somerset Pharmaceuticals and partner Bristol-Myers Squibb are facing a three-month delay in their bid to get a transdermal product to treat depression onto the US market, as the US Food and Drug Administration (FDA) digests dietary restriction data.

Somerset, a joint venture between Mylan Laboratories and Watson Pharmaceuticals, said yesterday that the FDA has extended until February 26 its action date for Emsam (selegiline), for the acute and maintenance treatment of major depressive disorders.

The extension is intended to give additional time to the FDA to review an amendment to the application dossier filed after last month's Psychopharmacologic Drug Advisory Committee, which concluded that Emsam could be safely administered without tyramine dietary modifications at its lowest dose of 20mg. Ahead of the meeting, the FDA had suggested that all three doses of the product (20mg, 30mg and 40mg patches) should carry the warnings

Tyramine is an amino acid found in dairy and meat products. All drugs products based on selegiline, a monoamine oxidase inhibitor, carry dietary warnings because if patients ingest too much tyramine while taking them they can suffer dramatic elevations in blood pressure.

Somerset received an ‘approvable’ letter for Emsam from the FDA in January 2004, and if cleared by the agency would be the first patch for the treatment of major depressive disorder.