WOODCLIFF LAKE, N.J., and STAMFORD, Conn, Oct. 31, 2016 — Eisai and Purdue Pharma L.P. announced today the initiation of a multi-center, randomized Phase 2 clinical study (Study 202) to evaluate Eisai’s internally-discovered oral dual orexin receptor antagonist lemborexant (E2006) in patients with mild to moderate Alzheimer’s disease dementia (AD) who suffer from Irregular Sleep-Wake Rhythm Disorder (ISWRD)[i]. Lemborexant is being jointly developed by Eisai and Purdue Pharma L.P.

ISWRD, often observed in patients with AD, is a type of circadian rhythm disorder, where there is no clear 24-hour sleep-wake pattern resulting in sleeping and waking occurring at irregular, inconsistent times during the day and night. There is no known treatment approved for this kind of irregular sleep-wake pattern in patients with various causes of dementia,[ii] signifying that this is a condition with high unmet medical need.

“Sleep-wake fragmentation and insomnia associated with dementia are serious problems – both for patients and their caregivers,” said Lynn Kramer, M.D., Chief Clinical Officer and Chief Medical Officer, Neurology Business Group, Eisai. “Through research and development on lemborexant, we are striving to fulfill new unmet medical needs for this type of insomnia disorder.”

“We look forward to enrolling patients in these placebo-controlled studies to evaluate the clinical benefits of lemborexant in the treatment of ISWRD, which would be an important development for this underserved patient population,” said Alan W. Dunton, MD, Head of Research & Development, Purdue Pharma L.P.

About the studyi

Study 202 will evaluate the efficacy and safety of lemborexant in 125 patients aged 65 to 90 with ISWRD and mild to moderate AD. Patients are randomized to receive 2.5, 5, 10 or 15 mg of lemborexant or placebo orally once daily for four weeks. The primary endpoint will be the dose response of the change from baseline of actigraphy-based sleep efficiency and wake efficiency during the last seven nights of four weeks of treatment with lemborexant compared to placebo.  These changes will be measured using actigraphy, a non-invasive device worn on the wrist which is used to assess the circadian rhythm of sleep-wake patterns continuously for many days.

About Lemborexant

Discovered by Eisai, lemborexant is a dual orexin receptor antagonist which competitively binds to the two subtypes of orexin receptors. The orexin system is a major regulator of the sleep-wake system.

In addition to this Phase 2 study, Eisai and Purdue Pharma initiated a Phase 3 Study in May 2016 (Study 304) in patients with insomnia to determine the efficacy and safety of lemborexant in 950 patients 55 and older with insomnia disorder.

This release discusses an investigational use of an agent in development and is not intended to convey conclusions about efficacy and safety.  There is no guarantee that any investigational use of this product will successfully complete clinical development or gain FDA approval. 


Purdue Pharma is a privately-held pharmaceutical company and is part of a global network of independent associated companies that is known for pioneering research in chronic pain and opioids with abuse deterrent properties. The company’s leadership and employees are committed to providing healthcare professionals, patients and caregivers quality products and educational resources to support their proper use. Purdue Pharma is engaged in the research, development, production and distribution of both prescription and over-the-counter medicines and hospital products. With Purdue Pharma’s expertise in drug development, commercialization and life-cycle management, the company is diversifying in high-need areas to expand through strategic acquisitions and creative partnerships. For more information, please visit www.purduepharma.com.


At Eisai Inc., human health care (hhc) is our goal. We give our first thought to patients and their families, and helping to increase the benefits health care provides. As the U.S. pharmaceutical subsidiary of Tokyo-based Eisai Co., Ltd., we have a passionate commitment to patient care that is the driving force behind our efforts to discover and develop innovative therapies to help address unmet medical needs.

Eisai is a fully integrated pharmaceutical business that operates in two global business groups: oncology and neurology (dementia-related diseases and neurodegenerative diseases). Each group functions as an end-to-end global business with discovery, development, and marketing capabilities. Our U.S. headquarters, commercial and clinical development organizations are located in New Jersey; our discovery labs are in Massachusetts and Pennsylvania; and our global demand chain organization resides in Maryland and North Carolina. To learn more about Eisai Inc., please visit us at www.eisai.com/US.



i A Multicenter, Randomized, Double-Blind, Placebo—Controlled, Parallel-Group Study of the Efficacy and Safety of Lemborexant in Subjects with Irregular Sleep-Wake Rhythm Disorder and Mild to Moderate Alzheimer’s Disease in Dementia.

ii Abbott SM, Zee PC. Irregular Sleep-Wake Rhythm Disorder. Sleep Med Clin. 2015; 10:517–522.