Abstract
AIMS: Lemborexant, a dual orexin receptor antagonist, is approved for treating adults with insomnia. We present diary-based sleep parameters, self-reported sleep quality, insomnia severity, and health-related quality of life following direct transition to lemborexant from previous treatment in Japanese patients with insomnia using data from the SOMNUS Study. METHODS: The prospective, nonrandomized, open-label, multicenter SOMNUS Study analyzed data from 90 patients across four cohorts of direct switching to lemborexant from Z-drugs (monotherapy cohort: n = 25), suvorexant (monotherapy cohort: n = 25, combination cohort: n = 21), and ramelteon (combination cohort: n = 19) up to 14 weeks. RESULTS: Diary-based sleep parameters (subjective sleep onset latency, subjective wake time after sleep onset, subjective total sleep time, and subjective sleep efficiency) significantly improved after transitioning to lemborexant in the 90 patients. At 2, 6, and 14 weeks, significant reductions in Insomnia Severity Index total scores were observed (-2.6 ± 3.81, -4.4 ± 5.13, and -5.3 ± 4.80, respectively; all p < 0.0001). Self-reported sleep quality and morning alertness also showed consistent, significant improvements across all time points. Short Form-8 physical component summary and mental component summary scores demonstrated positive trends, with notable improvements observed in the overall population by the end of the study. Treatment-emergent adverse events (TEAEs) occurred in 47.8 % of patients; most were mild or moderate in severity. No serious TEAEs occurred; somnolence was the most common TEAE. CONCLUSIONS: These findings indicate that transitioning to lemborexant from previous insomnia treatment is efficacious in improving sleep parameters, insomnia severity, and health-related quality of life, with a favorable safety profile. TRIAL REGISTRATION: NCT04742699.