Long-term Effectiveness and Safety of Lemborexant in Adults with Insomnia Disorder: Results from a Phase 3 Randomized Clinical Trial

Objective/background: Lemborexant is a dual orexin receptor antagonist approved in the United States, Japan, and Canada for the treatment of insomnia in adults. We report effectiveness and safety outcomes in subjects with insomnia who received up to twelve months of continuous lemborexant treatment in Study E2006-G000-303 (Study 303; SUNRISE-2).

Patients/methods: Study 303 was a twelve-month, global, multicenter, randomized, double-blind, parallel-group, Phase 3 study divided into two treatment periods. In Treatment Period 1 (first six months), subjects (n = 949, Full Analysis Set) were randomized to daily placebo, lemborexant 5 mg (LEM5) or lemborexant 10 mg (LEM10). In Treatment Period 2 (second six months), placebo subjects were rerandomized to LEM5 or LEM10, and subjects randomized to lemborexant continued their assigned treatment (LEM5, n = 251; LEM10, n = 226). Sleep onset and sleep maintenance endpoints were analyzed from daily electronic sleep diary data. Treatment-emergent adverse events (TEAEs) were monitored.

Results: For all sleep parameters, the significant benefits observed with LEM5 and LEM10 versus placebo over six months were maintained at twelve months in subjects who received twelve continuous months of treatment. There was no evidence of rebound insomnia or withdrawal in either lemborexant group following treatment discontinuation. Over twelve months of lemborexant treatment, most TEAEs were mild/moderate; the most common TEAEs were nasopharyngitis, somnolence and headache.

Conclusions: LEM5 and LEM10 had significant benefit on sleep onset and sleep maintenance compared with placebo, and importantly, lemborexant effectiveness persisted at twelve months, suggesting that lemborexant may provide long-term benefits for subjects with insomnia.

Clinical Trial Registration: ClinicalTrials.gov, NCT02952820; ClinicalTrialsRegister.eu, EudraCT Number 2015-001463-39.