Effects of Suvorexant on the Insomnia Severity Index in Patients with Insomnia: Analysis of Pooled Phase-3 Data (P4.292)

Objective: To evaluate the effects of suvorexant on the Insomnia Severity Index (ISI) which assesses sleep problems and their impact on daytime function. Background: Previously-reported Phase-3 results showed that the orexin receptor antagonist suvorexant improves sleep maintenance and onset. Methods: The analysis included pooled-data from two similar randomized, double-blind, placebo-controlled, parallel-group, 3-month trials in elderly (≥65y) and non-elderly (18-64y) insomnia patients. Age-adjusted (non-elderly/elderly) dose-regimes of 40/30mg and 20/15mg were evaluated. Fewer patients were assigned to 20/15mg than 40/30mg or placebo. The ISI, a 7-item patient questionnaire, was administered as an exploratory assessment at Months 1 and 3. Results: 1824 patients were included in the analysis. Compared to placebo, suvorexant improved change-from-baseline in total score at both timepoints (Month 3: 20/15mg = -6.2, 40/30mg = -6.7, placebo = -4.9, p-values u003c0.001) and the percentage of responders (≥6-point improvement from baseline) at both timepoints (Month 3: 20/15mg = 55.5[percnt], 40/30mg = 54.9[percnt], placebo = 42.2[percnt], p-values u003c0.001). Scores for individual items of the ISI showed numerical improvement for both suvorexant dose regimes versus placebo at both timepoints; the “impact of insomnia” component (last 3 items) which assesses the impact of insomnia on daytime function/quality-of-life was also improved by both dose regimes. Conclusions: Suvorexant 20/15mg and 40/30 mg improve sleep as assessed by the ISI in patients with insomnia. Improvement in sleep onset/maintenance as well as a reduction of the impact of sleep problems on daytime function contribute to the overall improvement observed in ISI total score. Given that the maximum approved dose is 20mg, the 20/15mg data are the most clinically relevant. Study Support: Merck u0026 Co. Inc., Kenilworth, NJ, USA Disclosure: Dr. Herring has received personal compensation for activities with Merck u0026 Co. Inc., as an employee. Dr. Snyder has received personal compensation for activities for Merck. Dr. Snavely has received personal compensation for activities with Merck u0026 Co., Inc. as an employee. Dr. Lines has received personal compensation for activities with Merck as an employee. Dr. Michelson has received personal compensation for activities with Merck u0026 Co., Inc. as an employee.