347 Daridorexant is Safe and Improves Both Sleep and Daytime Functioning in Elderly Patients with Insomnia

Abstract

Introduction Insomnia affects elderly more than younger adults, and comorbidities more prevalent in elderly populations can add to symptom burden and reduce therapeutic options. Drugs that improve insomnia symptoms with limited safety risks are needed to treat this patient group. We report elderly subgroup analyses from a Phase-3 registration trial with daridorexant. Methods In this multi-center, double-blind trial (NCT03545191), adult (18–64y) and elderly (≥65y) patients with insomnia were randomized (1:1:1) to receive oral daridorexant 25mg, 50mg or placebo every evening for 3 months. Month 3 endpoints were: change from baseline in polysomnography-measured wake-after-sleep-onset (WASO) and latency-to-persistent-sleep (LPS) (both primary endpoints), subjective total sleep time (sTST), and daytime functioning (Insomnia Daytime Symptoms and Impacts Questionnaire [IDSIQ] – sleepiness domain; with a lower score indicating improved daytime functioning). Safety endpoints included treatment emergent adverse events (TEAE), AEs of special interest (AESI; symptoms related to excessive daytime sleepiness or complex sleep behavior, and suicidal ideation/self-injury) and withdrawal effects upon treatment cessation (assessed by the Benzodiazepine Withdrawal Symptom Questionnaire total score and relevant AEs). Results Of the 930 patients randomized, 364 (39.1%) were ≥65y: daridorexant 25mg (n=121), 50mg (n=121) and placebo (n=122). In this subgroup, at Month 3, the placebo-corrected least-square mean of change from baseline [95%CL] for daridorexant 25mg and 50mg were: WASO -17.0[-27.0,-7.0] and -19.6[-29.5,-9.7] mins; LPS -7.8[-15.2,-0.4] and -14.9[-22.3,-7.5] mins; sTST 18.7[4.1,33.2] and 30.6[16.1,45.2] mins; IDSIQ sleepiness domain -0.6[-2.2,0.9] and -2.6[-4.1,-1.0], all respectively. TEAEs were reported in 32.2%, 35.3%, and 31.1% of patients ≥65y in the 25mg, 50mg and placebo groups, respectively. Falls (n=1,1,4 for 25mg, 50mg, placebo, respectively) and dizziness (n=4,1,1), both of particular interest in elderly, were least frequent in the 50mg group. Compared to placebo, somnolence was as frequent for 50mg daridorexant (n=6,1,1) while fatigue was more frequent in both daridorexant groups (n=4,3,1); incidence did not appear dose-related. AESI, of mild intensity, were reported in 2 patients ≥65y (one in each daridorexant group). There was no evidence of withdrawal symptoms. Conclusion Daridorexant is efficacious in the elderly population for improvements in sleep and daytime functioning. No safety concerns in this vulnerable population were identified at either dose. Support (if any) Funded by Idorsia Pharmaceuticals Ltd.