Sepracor Inc announced that the United States Patent and Trademark Office has determined that US Patent No. 6,444,673, which is a composition of matter patent that covers the human drug product Lunesta (eszopiclone), received a patent term extension under 35 USC § 156. The period of extension was determined to be 760 days, and the new expiration date of the patent is February 14, 2014.

Lunesta is marketed by Sepracor for the treatment of insomnia. In addition, the exclusivity period could potentially be extended for an additional six months if Sepracor successfully obtains a paediatric exclusivity extension by submitting data developed in accordance with the pediatric Written Request.

In 2008 and early 2009, Sepracor completed two paediatric studies of Lunesta in response to a Written Request from the US Food and Drug Administration (FDA) in connection with its efforts to obtain paediatric exclusivity for Lunesta. In April 2009, Sepracor initiated two additional paediatric studies in accordance with the US FDA's Written Request. In July, the US FDA notified Sepracor that it placed these two studies on clinical hold due to its concerns regarding non-clinical data that the US FDA thought could be relevant to the administration of eszopiclone in children. The US FDA recently informed Sepracor that the clinical hold placed on these Lunesta paediatric studies has now been lifted. The company is in the process of determining the next steps for the trials.

Lunesta brand eszopiclone is a non-narcotic non-benzodiazepine indicated for the treatment of insomnia.