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Updated: May 22, 2026

Optogenetic Manipulation of Neural Circuits During Monitoring Sleep/wakefulness States in Mice
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Optogenetic Manipulation of Neural Circuits During Monitoring Sleep/wakefulness States in Mice

Published on: June 19, 2019

Orexin receptor antagonism, a new sleep-enabling paradigm: a proof-of-concept clinical trial

P Hoever1, G Dorffner, H Beneš

  • 1Actelion Pharmaceuticals Ltd., Allschwil, Switzerland.

Clinical Pharmacology and Therapeutics
|May 3, 2012
PubMed

Insights

Almorexant, a dual orexin receptor antagonist, significantly improved sleep efficiency and reduced sleep latency in primary insomnia patients. This study suggests the orexin system offers a promising new treatment for insomnia.

Area of Science:

  • Neuroscience
  • Sleep Medicine

Background:

  • The orexin system critically regulates sleep-wake cycles.
  • Primary insomnia is a prevalent sleep disorder with significant impact on quality of life.

Purpose of the Study:

  • To evaluate the efficacy and safety of almorexant, a dual orexin receptor antagonist, in treating primary insomnia.
  • To assess the dose-dependent effects of almorexant on sleep parameters.

Main Methods:

  • A multicenter, double-blind, randomized, placebo-controlled, two-way crossover study.
  • 161 primary insomnia patients received almorexant (50-400 mg) or placebo in 1-week intervals.
  • Sleep efficiency (SE), latency to persistent sleep (LPS), and wake after sleep onset (WASO) were measured by polysomnography.

Main Results:

  • Almorexant demonstrated dose-dependent improvements in SE, LPS, and WASO.
  • Significant improvement in SE (14.4%) and reduction in LPS (–18 min) and WASO (–54 min) were observed at 400 mg compared to placebo.
  • Adverse event incidence was dose-related.

Conclusions:

  • Almorexant consistently and dose-dependently improved key sleep variables in patients with primary insomnia.
  • The orexin system presents a potential novel therapeutic target for primary insomnia treatment.

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