Eisai Co., Ltd. (Headquarters: Tokyo, President & CEO: Haruo Naito, “Eisai”) announced today that it received approval from Japan's Ministry of Health, Labour and Welfare (MHLW) on January 18, 2012 to market Lunesta® (eszopiclone), a product the company has been developing in Japan, as a treatment for insomnia.

Lunesta, originally discovered and developed by Sunovion Pharmaceuticals Inc. (“Sunovion”; formerly Sepracor Inc., “Sepracor”; a U.S. subsidiary of Dainippon Sumitomo Pharma Co., Ltd.), has been marketed in the United States since April 2005. The agent was approved as the first insomnia treatment not to have restrictions on its length of use, and is widely used by individuals suffering from insomnia. Eisai has been pursuing the development of Lunesta since acquiring the exclusive rights to develop and market it in Japan from Sunovion (at the time known as Sepracor) in July 2007. The company submitted a marketing authorization application to the MHLW in November 2010.

Lunesta is a non-benzodiazepine type GABAA agonist that is believed to enhance GABA activity while exerting hypnotic and sedative effects. Results from clinical studies conducted in Japan and overseas demonstrated that the agent is effective in those patients who have trouble falling asleep or wake up often during the night, two major symptoms of insomnia. A distinctive feature of Lunesta is that patients do not experience clinically problematic issues such as dependency or carry-over effects or develop a tolerance (experience diminished efficacy) with long-term use.

In a Phase II/III study (Study 126) conducted in Japan in patients with primary insomnia, Lunesta was shown to statistically significantly improve Sleep Latency (SL)1) as measured against placebo. In addition, Lunesta was shown in Study 126 to cause a statistically significant (when measured against placebo) reduction in latency to persistent sleep (LPS), as objectively measured by an overnight polysomnography (PSG)2). The measurement of the impact of Lunesta on SL and LPS were the two co-primary endpoints of Study 126. The favorable safety profile of Lunesta was also confirmed in a long-term study (Study 150) in patients with various forms of insomnia, including elderly adults and adults with insomnia associated with psychological disorders.

Insomnia is a condition that has a repeated negative effect on a person's ability to fall asleep, remain asleep or obtain quality of sleep, and can interfere with everyday activities despite having ample opportunity to sleep. In Japan, it is estimated that more than 20 million people suffer from some kind of sleep disorder and this number expected to increase even further.

By providing Lunesta as a new treatment for insomnia, Eisai seeks to make contributions to increase the benefits provided to patients.

  • 1)
    Sleep latency (SL): the interval from “lights out” until sleep begins
  • 2)
    Overnight polysomnography (PSG): a diagnostic tool that measures brain activity, eye movement, and skeletal muscle activation to simultaneously record throughout the night the biophysical activity that occurs during sleep

[ Please refer to the following notes for a product outline as well as further information on Lunesta® and Japan clinical studies ]

Media Inquiries:

Public Relations Department,
Eisai Co., Ltd.

< Notes to editors >

1. Product Outline

  • 1)

    Product Name

    Lunesta® Tablets 1 mg, Lunesta® Tablets 2 mg, Lunesta® Tablets 3 mg

  • 2)

    Generic Name


  • 3)

    Indications and Usage


  • 4)

    Dosage and Administration

    The recommended dose of eszopiclone is 2 mg for non-elderly adults and 1mg for elderly adults taken orally immediately before bedtime. Dosage may be adjusted according the patients symptoms; however, it should not excess 3 mg per dose for non-elderly adults or 2 mg per dose for elderly patients.

2. About Lunesta

Lunesta is a non-benzodiazepine type GABAA agonist (non-benzodiazepine sedative hypnotic) that was originally discovered and developed by Sunovion Pharmaceuticals Inc. (formerly Sepracor Inc.). It is an S-enantiomer obtained through optical resolution of the racemic compound (a mixture containing equal parts of the R- and S-enantiomers) zopiclone. Sleep is thought to be induced as a result of inhibition of (excitatory) neurotransmission in the brain's arousal system, with the neurogenic amino acid derivative GABA (γ-aminobutyric acid) serving as the chief inhibitory neurotransmitter. GABAA agonists are thought to enhance GABA effects and induce sleep by binding directly or allosterically to the ionotropic GABAA receptor complex. Clinical trials conducted overseas have confirmed that Lunesta is effective in treating transient and chronic insomnia and that it can be used over the long term without patients developing a tolerance to it. In other words, its efficacy does not diminish over time. The marketing authorization application submitted in Japan was based on data from the following domestic clinical trials as well as data from trials conducted overseas.

3. Japan Clinical Trials

  • 1)

    Study 126

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Study Design: Multicenter, randomized, placebo-controlled, 5-way crossover, double-blind comparison
Eligibility: Chronic insomnia patients aged between 21 and 64 years old who had been diagnosed with primary insomnia (72 subjects)
Primary Objective: To investigate and evaluate the dose response of eszopiclone and its superiority relative to placebo
Treatment Arms: eszopiclone 1 mg, 2 mg, 3 mg, placebo, zolpidem tartrate 10 mg
Treatment Period: Five treatment phases for two consecutive nights, each separated by a washout period of four to six days
Primary Endpoints: Latency to persistent sleep (LPS), as measured by an overnight polysomnography (PSG), and sleep latency (SL), as measured by subjective evaluation
  • 2)


Study Design: Multicenter, randomized, parallel-arm, double-blind comparison
Eligibility: Chronic insomnia patients aged between 20 and 84 years old (325 subjects)
Primary Objective: To evaluate the long-term safety of eszopiclone
Treatment Arms: Non-elderly adults: eszopiclone 2 mg, 3 mg; Elderly adults: eszopiclone 1 mg, 2 mg
Treatment Period: Once daily for a period of 24 weeks
Primary Endpoints: Adverse events