Eisai Inc. and Purdue Pharma L.P. announced 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). 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, signifying that this is a condition with high unmet medical need.

“Sleep-wake fragmentation and sleep complaints associated with dementia are serious problems—both for patients and their caregivers,” says Lynn Kramer, MD, chief clinical officer and chief medical officer, Neurology Business Group, Eisai, in a release. “Through research and development on lemborexant, we are striving to potentially fulfill unmet medical needs for this type of sleep disorder.”

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

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 will be randomized to receive 2.5, 5, 10 or 15 mg of lemborexant or placebo orally once daily for four weeks. Over the four weeks of treatment with lemborexant compared to placebo, the primary endpoint will be the dose response of the change from baseline in actigraphy-based sleep efficiency and wake efficiency during the last seven nights of treatment. Patients and investigators interested in participating in this trial should contact Eisai Medical Information at 1-888-274-2378.

About Lemborexant

Discovered by Eisai, lemborexant is a dual orexin receptor antagonist that 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 L.P. initiated a Phase 3 Study in May 2016 (Study 304) in patients with insomnia disorder 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 this investigational agent will successfully complete clinical development or gain FDA approval.