IMPAX Laboratories, Inc. and ThoRx Laboratories Confirm Patent Challenge Relating to Generic OPANA® ER 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg, 30 mg, and 40 mg

HAYWARD, Calif.--(BUSINESS WIRE)--Impax Laboratories, Inc. (NASDAQ: IPXL) and its wholly owned subsidiary, ThoRx Laboratories, Inc., today confirm that they have initiated a challenge of the patents listed in the Orange Book in connection with Opana® ER (oxymorphone hydrochloride extended-release tablets, 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg, 30 mg, and 40 mg). ThoRx filed its Abbreviated New Drug Application (ANDA) containing a paragraph IV certification for a generic version of Opana® ER with the U.S. Food & Drug Administration (FDA). Following receipt of the notice from FDA that ThoRx’s ANDA had been accepted for filing, ThoRx notified the New Drug Application holder and patent owner of its paragraph IV certification. On November 14, 2012, Endo Pharmaceuticals Inc. and Grunenthal GMBH filed suit for patent infringement against ThoRx Laboratories, Inc. and Impax Laboratories, Inc. in the United States District Court for the Southern District of New York. This action formally initiates the patent challenge process under the Hatch-Waxman Act.

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