Barr Pharmaceuticals, Inc. has confirmed that its subsidiary, Barr Laboratories, Inc., has initiated a challenge of the patent listed by Boehringer Ingelheim in connection with its Aggrenox (Aspirin/Extended- Release Dipyridamole) 25 mg/200 mg capsules.

The company believes that it is the first to file an Abbreviated New Drug Application (ANDA) containing a paragraph IV certification for Aggrenox.
Barr filed its ANDA containing a paragraph IV certification for a generic Aggrenox product with the US Food and Drug Administration (FDA) in January 2007, and received notification of the application's acceptance for filing in May 2007. Following receipt of the notice from the FDA, Barr notified the New Drug Application (NDA) holder and patent owner.

On July 11, 2007, Boehringer Ingelheim, et al., filed suit in the US district court of Delaware to prevent Barr from proceeding with the commercialization of its product. This action formally initiates the patent challenge process under the Hatch-Waxman Act.

Aggrenox capsules are indicated to reduce the risk of stroke in patients who have had transient ischemia of the brain or completed ischemic stroke due to thrombosis. The product had sales of approximately $258 million in the US, based on IMS sales data for the twelve months ended May 2007.