Gilead sues to stop Actavis' generic bid for Letairis

Actavis plc on Friday said it filed an Abbreviated New Drug Application (ANDA) with FDA seeking approval to market ambrisentan tablets, a generic version of Gilead Sciences, Inc.'s Letairis, a treatment for pulmonary arterial hypertension.

However, Gilead Sciences and Royalty Pharma Collection Trust filed suit against Actavis on April 1 in the U.S. District Court for the District of Delaware, seeking to prevent Actavis from commercializing its ANDA product prior to the expiration of U.S. Patent number RE42,462.  

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“Actavis believes it may be a ‘first applicant’ to file an ANDA for the generic version of Letairis and, should its ANDA be approved, may be entitled to 180 days of generic market exclusivity,” according to a statement from Actavis, based in Dublin, Ireland. For the 12 months ending December 31, 2014, Letairis had global sales of approximately $595 million, according to Gilead.

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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, according to Actavis.

In February, Watson Laboratories Inc. also challenged Gilead’s patent, saying it was seeking FDA permission to sell a generic version of Letairis.

Last month, Actavis completed its acquisition of Allergan Inc., now valued at $70.5 billion, closing the biggest deal from 2014 and ending one of the year’s more dramatic takeover battles, according to The Wall Street Journal. 

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