Watson Pharmaceuticals, Inc. announced that Actavis South Atlantic LLC has filed an Abbreviated New Drug Application (ANDA) with the US Food and Drug Administration (FDA) seeking approval to market oxymorphone hydrochloride extended-release tablets.

Watson has acquired Actavis South Atlantic LLC in October. Actavis' ANDA product is a generic version of the currently marketed formulation of Endo Health Solutions' Opana ER, which is an opioid agonist indicated for the relief of moderate to severe pain in patients requiring continuous around-the-clock opioid treatment for an extended period of time.

Endo and Grunenthal GmbH filed suit against Actavis on January 18, 2013, in the US District Court for the Southern District of New York seeking to prevent Actavis from commercializing its ANDA product prior to the expiration of certain US patents. The lawsuit was filed under the provisions of the Hatch-Waxman Act, resulting in a stay of final FDA approval of Actavis' ANDA for up to 30 months from the date the plaintiffs received notice of Actavis' ANDA filing or until final resolution of the matter before the court, whichever occurs sooner, subject to any other exclusivities.

For the 12 months ending November 30, 2012, Opana ER had total US sales of approximately $512 million according to IMS Health data.

Watson Pharmaceuticals, Inc. is a global, integrated specialty pharmaceutical company focused on developing, manufacturing and distributing generic, brand and biosimilar products.