Barr Pharmaceuticals, Inc. said that its subsidiary, Barr Laboratories, Inc., has initiated a challenge of the patents listed by sanofi- aventis US LLC in connection with its Uroxatral (alfuzosin hydrochloride extended-release tablets), 10mg.

Barr's Abbreviated New Drug Application (ANDA) containing a paragraph IV certification for a generic Uroxatral product was received as acceptable for filing by the US Food and Drug Administration (FDA) on June 12, 2007, the first date the FDA could accept an ANDA with a paragraph IV certification for this product. Following receipt of the notice from the FDA that Barr's ANDA had been accepted for filing, Barr notified the NDA and patent holder, said a Barr press release.

On September 21, 2007, sanofi-aventis filed suit in the US District Court for the District of Delaware (Wilmington) to prevent Barr from proceeding with the commercialisation of its product. This action formally initiates the patent challenge process under the Hatch-Waxman Act. Barr understands other companies have filed an ANDA for alfuzosin hydrochloride extended-release tablets, and have been sued.

Uroxatral (alfuzosin hydrochloride extended-release tablets) is indicated for the treatment of the signs and symptoms of benign prostatic hyperplasia. The product had annual sales of approximately $140 million in the US, based on IMS sales data ending July 2007.