Effect of Lemborexant on Daytime Functioning in Adults With Insomnia: Patient-Reported Outcomes From a Phase 3 Clinical Trial.

Objective: Insomnia and some insomnia treatments can impact an individual's daytime functioning. Here, we performed post hoc analyses of patient-reported outcomes from a phase 3 clinical trial to assess the impact of lemborexant (LEM), a dual orexin receptor antagonist, on daytime functioning. Methods: Adults with insomnia were randomized 1:1:1 to receive placebo, LEM 5 mg (LEM5) or LEM 10 mg (LEM10) for 6 months. Treatment impact on subjects' perceptions of their insomnia symptoms and daytime functioning was assessed by the Insomnia Severity Index (ISI) and Fatigue Severity Scale (FSS) questionnaires. Safety assessments included monitoring of treatment emergent adverse events. Results: Compared with placebo, LEM5 and LEM10 treatment significantly improved ISI Total Score (ISI-TS) (LEM5, P < .01; LEM10, P < .0001) and ISI Daytime Functioning Score (ISI-DFS) (LEM5, P < .05; LEM10, P < .01) at 1 month; these improvements were maintained at the end of 6 months (P < .0001 for LEM5 and LEM10, both scores). In separate analyses, baseline ISI-TS or ISI-DFS was used to classify subjects' symptom severity into 1 of 4 categories. At 1 and 6 months, greater proportions of subjects treated with LEM5 and LEM10 shifted to a category associated with less severe symptoms (P < .01 for all comparisons vs placebo). FSS score also improved with LEM treatment vs placebo as assessed at month 3; improvements were maintained at month 6 (P < .05). LEM5 and LEM10 treatment was well tolerated. Conclusion: Improved insomnia symptoms with LEM treatment may translate into improved daytime functioning, suggesting LEM may be appropriate for adults experiencing daytime impairment with their nighttime symptoms. Trial Registration: ClinicalTrials.gov identifier: NCT02952820. Prim Care Companion CNS Disord 2025;27(1):24m03810. Author affiliations are listed at the end of this article.