Suvorexant in Elderly Patients with Insomnia: Pooled Analyses of Data from Phase III Randomized Controlled Clinical Trials

Abstract

Objective: Suvorexant is an orexin receptor antagonist approved for treating insomnia at doses of 10-20 mg. Previously reported phase III results showed that suvorexant was effective and well-tolerated in a combined-age population (elderly and nonelderly adults). The present analysis evaluated the clinical profile of suvorexant specifically in the elderly.

Methods: Prespecified subgroup analyses of pooled 3-month data from two (efficacy) and three (safety) randomized, double-blind, placebo-controlled, parallel-group trials. In each trial, elderly (≥65 years) patients with insomnia were randomized to suvorexant 30 mg, suvorexant 15 mg, and placebo. By design, fewer patients were randomized to 15 mg. Patient-reported and polysomnographic (subset of patients) sleep maintenance and onset endpoints were measured.

Results: Suvorexant 30 mg (N = 319) was effective compared with placebo (N = 318) on patient-reported and polysomnographic sleep maintenance, and onset endpoints at Night 1 (polysomnographic endpoints)/Week 1 (patient-reported endpoints), Month 1, and Month 3. Suvorexant 15 mg (N = 202 treated) was also effective across these measures, although the onset effect was less evident at later time points. The percentages of patients discontinuing because of adverse events over 3 months were 6.4% for 30 mg (N = 627 treated), 3.5% for 15 mg (N = 202 treated), and 5.5% for placebo (N = 469 treated). Somnolence was the most common adverse event (8.8% for 30 mg, 5.4% for 15 mg, 3.2% for placebo).

Conclusion: Suvorexant generally improved sleep maintenance and onset over 3 months of nightly treatment and was well-tolerated in elderly patients with insomnia (clinicaltrials.gov; NCT01097616, NCT01097629, NCT01021813).

Keywords: Suvorexant; efficacy; orexin; randomized clinical trial; safety.