Effects of TS-142, a novel dual orexin receptor antagonist, on sleep in patients with insomnia: a randomized, double-blind, placebo-controlled phase 2 study

RATIONALE: Novel compound with potent antagonistic activity against orexin receptors may be new treatment option for patients with insomnia. OBJECTIVE: The aim was to investigate the efficacy and safety of single oral doses of the dual orexin receptor antagonist TS-142 in patients with insomnia. METHODS: This multicenter, double-blind, crossover randomized clinical trial included non-elderly patients with insomnia. Patients were randomized to receive single doses of placebo and TS-142 at doses of 5, 10, and 30 mg in one of four different sequences, with a 7-day washout period between treatments. Primary efficacy endpoints were latency to persistent sleep (LPS) and wake time after sleep onset (WASO) measured by polysomnography. RESULTS: Twenty-four patients were included (mean age 50.3 ± 10.5 years; mean duration of insomnia 5.71 ± 8.68 years). Least-squares mean differences (95% confidence interval) from placebo in LPS with 5, 10, and 30 mg TS-142 were − 42.38 (− 60.13, − 24.63), − 42.10 (− 60.02, − 24.17), and − 44.68 (− 62.41, − 26.95) minutes, respectively (all p < 0.001). Least-squares mean differences (95% confidence interval) from placebo in WASO with 5, 10, and 30 mg TS-142 were − 27.52 (− 46.90, − 8.14), − 35.44 (− 55.02, − 15.87), and − 54.69 (− 74.16, − 35.23) minutes, respectively (all p < 0.01). Self-reported aspects of sleep initiation and sleep quality, determined using the Leeds Sleep Evaluation Questionnaire (LSEQ), were also improved with TS-142 administration versus placebo. TS-142 was well tolerated; all adverse events were mild or moderate and none were serious. CONCLUSION: Single-dose TS-142 was well tolerated and had clinically relevant effects on objective and subjective sleep parameters in patients with insomnia. CLINICAL TRIAL REGISTRATION: JapicCTI173570 (www.clinicaltrials.jp); NCT04573725 (www.clinicaltrials.gov).