Impax confirms challenge of patents in connection with INTUNIV

Dec 3 2010

Impax Laboratories, Inc. (NASDAQ: IPXL) today confirms that it has initiated a challenge of patents listed by Shire Development Inc. in connection with INTUNIV^TM (guanfacine hydrochloride), 4 mg.

Impax filed its Abbreviated New Drug Application (ANDA) containing a paragraph IV certification for a generic version of INTUNIV^™ with the U.S. Food & Drug Administration (FDA). Following receipt of the notice from the FDA that Impax's ANDA had been accepted for filing, Impax notified the New Drug Application holder and patent owners of its paragraph IV certification.

On December 2, 2010, Shire LLC, Supernus Pharmaceuticals, Inc., Amy F.T. Arnsten, Pasko Rakic, and Richard D. Hunt filed suit for patent infringement against Impax in the United States District Court for the Northern District of California. This action formally initiates the patent challenge process under the Hatch-Waxman Act.

Once the ANDA is approved by FDA, Global Pharmaceuticals, Impax's generic division, will commercialize the products.

INTUNIV^™ is indicated for the treatment of Attention Deficit Hyperactivity Disorder. According to Wolters Kluwer Health, U.S. sales of INTUNIV^™, 4 mg, were approximately $14 million for the twelve-month period ending September 30, 2010.

SOURCE Impax Laboratories, Inc.