Barr confirms Ambien patent challenge

USA-based Barr Laboratories has initiated a patent challenge for French drug major Sanofi-Aventis' Ambien CR (zolpidem tartrate) extended-release tablets, 6.25mg and 12.5mg.

Barr filed its Abbreviated New Drug Application containing a paragraph IV certification for a generic Ambien CR product with the Food and Drug Administration in December 2006, and received notification of the application's acceptance for filing in February 2007. Following receipt of the notice from the FDA, Barr notified Sanofi, the New Drug Application and patent owner.

On April 5, Sanofi-Aventis filed suit in the US District Court of New Jersey to prevent Barr from proceeding with the commercialization of its product. This action formally initiates the patent challenge process under the Hatch-Waxman Act, the US firm notes.