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Volume 12 No. 09
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Accepted Papers

Scientific Investigations

Suvorexant in Patients with Insomnia: Pooled Analyses of Three-Month Data from Phase-3 Randomized Controlled Clinical Trials

W. Joseph Herring, MD, PhD1; Kathleen M. Connor, MD1; Ellen Snyder, PhD1; Duane B. Snavely, MA1; Ying Zhang, PhD1; Jill Hutzelmann, MS1; Deborah Matzura-Wolfe, BS1; Ruth M. Benca, MD2; Andrew D. Krystal, MD3; James K. Walsh, PhD4; Christopher Lines, PhD1; Thomas Roth, PhD5; David Michelson, MD1
1Merck & Co., Inc., Kenilworth, NJ; 2University of Wisconsin, Madison, WI; 3Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC; 4Sleep Medicine and Research Center, St. Luke's Hospital, St. Louis, MO; 5Henry Ford Hospital Sleep Center, Detroit, MI

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Study Objectives:

Suvorexant is an orexin receptor antagonist approved for treating insomnia at a maximum dose of 20 mg. Phase-3 trials evaluated two age-adjusted (non-elderly/elderly) dose-regimes of 40/30 mg and 20/15 mg with the primary focus on 40/30 mg. We report here results from pooled analyses of the 20/15 mg dose-regime, which was evaluated as a secondary objective in the trials.


Prespecified analysis of pooled data from two identical randomized, double-blind, placebo-controlled, parallel-group, 3-month trials in non-elderly (18–64 years) and elderly (≥ 65 years) patients with insomnia. Patients were randomized to suvorexant 20/15 mg (non-elderly/elderly), suvorexant 40/30 mg (non-elderly/elderly), or placebo; by design, fewer patients were randomized to 20/15 mg. Efficacy was assessed by self-reported and polysomnography (PSG; subset of patients) sleep maintenance and onset endpoints.


Suvorexant 20/15 mg (N = 493 treated) was effective compared to placebo (N = 767 treated) on patient-reported and PSG sleep maintenance and onset endpoints at Night-1 (PSG endpoints) / Week-1 (subjective endpoints), Month-1 and Month-3, except for effects on PSG sleep onset at Month-3. Suvorexant 20/15 mg was generally well tolerated, with 3% of patients discontinuing due to adverse events over 3 months vs. 5.2% on placebo. Somnolence was the most common adverse event (6.7% vs. 3.3% for placebo). There was no systematic evidence of rebound or withdrawal signs or symptoms when suvorexant was discontinued after 3 months of nightly use.


Suvorexant 20/15 mg improved sleep onset and maintenance over 3 months of nightly treatment and was generally safe and well tolerated.

Clinical Trial Registration: trial registration numbers: NCT01097616, NCT01097629.


Herring WJ, Connor KM, Snyder E, Snavely DB, Zhang Y, Hutzelmann J, Matzura-Wolfe D, Benca RM, Krystal AD, Walsh JK, Lines C, Roth T, Michelson D. Suvorexant in patients with insomnia: pooled analyses of three-month data from phase-3 randomized controlled clinical trials. J Clin Sleep Med 2016;12(9):1215–1225.

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