Eisai Inc, the US subsidiary of Eisai Co Ltd, and Purdue Pharma LP presented results from two research studies on the novel oral dual orexin receptor antagonist lemborexant during the American College of Neuropsychopharmacology (ACNP) 56th annual meeting this month.

The abstract “Nonclinical evaluation of abuse liability for the novel orexin receptor antagonist lemborexant – comparison to suvorexant” presentation reported a non-clinical study demonstrating differences in lemborexant abuse liability when compared to a currently marketed insomnia treatment, suvorexant.

In the abstract “Efficacy of the novel dual orexin receptor antagonist lemborexant in a preclinical animal model of Irregular Sleep Wake Rhythm Disorder,” researchers presented a description of a potential preclinical animal model of Irregular Sleep-Wake Rhythm Disorder (ISWRD), as well as the effects of lemborexant treatment on sleep/wake patterns and circadian rhythmicity in this animal model. ISWRD, a condition in which sleep/wake patterns are irregular and unpredictable throughout the day and nighttime hours, is commonly seen in Alzheimer’s disease patients and is associated with behavioral disturbances including agitation and restlessness.

A lemborexant phase 2 clinical study, “Lemborexant, A Dual Orexin Receptor Antagonist (DORA) for the Treatment of Insomnia Disorder: Results from a Bayesian, Adaptive, Randomized, Double-Blind, Placebo-Controlled Study,” was recently published in the Journal of Clinical Sleep Medicine. This study evaluated multiple doses of lemborexant, demonstrating statistically significant improvement in sleep initiation and sleep maintenance without increasing next-day residual sleepiness compared to placebo. Adverse events were mostly mild to moderate, included dose-related somnolence, and were consistent with the known pharmacology of orexin receptor antagonists.1

Discovered by Eisai, lemborexant is a dual orexin receptor antagonist that inhibits orexin neurotransmitter activity by binding competitively to two subtypes of orexin receptors (orexin receptor 1 and 2). Lemborexant is being jointly developed by Eisai and Purdue. Information about currently enrolling clinical studies is available at clinicaltrials.gov.

This release discusses investigational uses of agents in development and is not intended to convey conclusions about efficacy or safety.