Sepracor Inc has filed a lawsuit in the US District Court for the District of New Jersey against those companies who have filed Abbreviated New Drug Applications (ANDAs) with Paragraph IV certifications for generic copies of eszopiclone. Sepracor markets eszopiclone in the US under the brand name Lunesta. The lawsuit alleges infringement of Sepracor's US Patent Numbers 6,319,926; 6,444,673; 6,864,257; and 7,381,724.

"Given the success of Lunesta, we were not surprised by the ANDA filings," said Adrian Adams, president and chief executive officer of Sepracor. "We believe that our patent position for Lunesta is strong, and we are prepared to vigorously protect our patent rights."

Due to the commencement of this litigation, ANDA approval will be stayed until approximately June 15, 2012 (or potentially six months thereafter if Sepracor successfully obtains a paediatric exclusivity extension) or until a court decides that Sepracor's patents are invalid, unenforceable or not infringed, whichever is earlier. Should Sepracor successfully enforce its patents, ANDA approval should not occur until expiration of the applicable patents, one of which may be extended by Sepracor's outstanding patent term extension application.

Sepracor is a research-based pharmaceutical company dedicated to treating and preventing human disease by discovering, developing and commercializing innovative pharmaceutical products that are directed toward serving large and growing markets and unmet medical needs.