Sepracor Inc. announced that it has received an "approvable" letter from the US Food and Drug Administration (FDA) for its New Drug Application (NDA) for Estorra brand eszopiclone 2 mg and 3 mg tablets for the treatment of insomnia characterized by difficulty falling asleep, and/or difficulty maintaining sleep during the night and early morning for adult and elderly patients, and a 1 mg tablet for elderly patients whose primary complaint is difficulty falling asleep. The FDA has not requested additional clinical or preclinical trials for final approval.

"We are very excited to have received an approvable letter from the FDA for Estorra," said Mark Corrigan, executive vice president of R&D at Sepracor. "The draft labeling is consistent with our proposals regarding indication and intended use. We are particularly pleased that the results of our six-month study are included in the draft labeling."

Contingent upon the outcome of our expected discussion with the agency and their assessment of our resubmission of the NDA, the company believes it is on track for an approval and launch of Estorra mid-2004 if the resubmission is categorized as Class One, which would involve a two-month FDA review. Sepracor would anticipate an approval and launch during the second half of 2004 if the resubmission is categorized as Class Two, which would involve a six-month FDA review.

The NDA, submitted in January 2003, contained 24 clinical trials, with more than 2,700 adult and elderly subjects, and 60 preclinical studies. Six randomized, placebo-controlled Phase III studies, one with a positive control, for the treatment of chronic or transient insomnia were conducted in both adult and elderly patients and were part of the NDA package.

According to the National Institutes of Health, insomnia affects more than 50 million Americans. Symptoms of insomnia include difficulty falling asleep, awakening frequently during the night, waking up too early, an inability to fall back to sleep, or awakening feeling unrefreshed.

According to the National Sleep Foundation (NSF) Sleep in America Poll 2003, 37 million older Americans suffer from frequent sleep problems that, if ignored, can complicate the treatment of several other medical conditions, from arthritis to diabetes, heart and lung disease and depression. This NSF poll shows that poor sleep among older adults often goes unnoticed by the medical community. Although the majority of older adults (67 per cent) report frequent sleep problems, only about seven million elderly patients have been diagnosed with sleep problems.

The US market for prescription sleep products, not including off-label (not indicated for the treatment of insomnia) use of central nervous system agents for the treatment of insomnia, was approximately $1.5 billion in 2002. The US prescription sleep agent market grew at a rate of almost 25 per cent for the past two years, according to IMS Health information.