Dual Orexin Receptor Antagonist, Almorexant, in Elderly Patients With Primary Insomnia: A Randomized, Controlled Study

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Objective: Sleep laboratory study to determine the dose-related efficacy and safety of almorexant in elderly patients with primary chronic insomnia.

Methods: Patients aged ≥65 years with primary insomnia were enrolled into a prospective, randomized, double-blind, placebo-controlled, multicenter dose-finding study with a five-period, five-way Latin square cross-over design. Patients were randomized to one of 10 unique sequences of two-night treatment with oral almorexant 25, 50, 100, or 200 mg capsules, or matching placebo. The primary efficacy endpoint was polysomnography (PSG)-determined mean wake time after sleep onset (WASO). Secondary and exploratory efficacy endpoints were also assessed.

Results: 112 patients were randomized (mean [SD] age 72.1 [5.0] years; 69.9% female). Significant, dose-related improvements (reductions) in mean WASO were observed with almorexant. Least-squares mean (95% CI) treatment effects in the almorexant 200, 100, 50, and 25 mg dose groups versus placebo were -46.5 minutes (-53.0, -39.9; p < .0001), -31.4 minutes (-38.0, -24.9; p < .0001), -19.2 minutes (-25.7, -12.6; p < .0001), and -10.4 minutes (-17.0, -3.9; p = .0018), respectively. Mean total sleep time was significantly increased with each almorexant dose (mean increases versus placebo ranged 55.1-14.3 minutes; p < .0001 for each dose). Latency to persistent sleep was statistically significantly reduced only with almorexant 200 mg versus placebo (mean [95% CI] treatment effect -10.2 minutes, [-15.4, -5.0]; p = .0001). No unexpected safety concerns were identified. Adverse events were similar between all almorexant dose groups and placebo.

Conclusions: Two-night oral administration of almorexant was effective and well tolerated in treating primary insomnia in elderly patients.

Medical Subject Headings

Acetamides; Aged; Aged, 80 and over; Chronic Disease; Cross-Over Studies; Dose-Response Relationship, Drug; Double-Blind Method; Drug Administration Schedule; Female; Follow-Up Studies; Humans; Isoquinolines; Male; Orexin Receptor Antagonists; Polysomnography; Prospective Studies; Sleep Initiation and Maintenance Disorders; Time Factors; Treatment Outcome

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