The pharmacokinetics, pharmacodynamics, and safety profile of vornorexant were investigated in healthy Japanese participants in three double‐blind studies: a single ascending dose of 1–30 mg (Study 101; n=6) and multiple ascending doses of 10–30 mg (Study 102; n=6). Study 202 consisted of two steps: an open‐label, 20 mg repeated‐dose in non‐elderly individuals (Step 1; n=12) and a double‐blind, 20 mg repeated‐dose in elderly individuals (Step 2; n=8/3 for vornorexant/placebo). Vornorexant was rapidly absorbed and eliminated under fasting conditions, with a time to maximum plasma concentration of 0.500–3.00 h (range) and elimination half‐life of 1.32–3.25 h. The area under the plasma concentration‐time curve (AUC) of vornorexant increased proportionally with dose increments. Sleepiness‐related pharmacodynamic outcome changes (Karolinska Sleepiness Scale, Digit Symbol Substitution Test, and Psychomotor Vigilance Task) were generally increased with dose increments at 1 and 4 h post‐dose, whereas no consistent dose‐related changes were detected the next morning. Food intake did not affect the maximum observed plasma concentration of vornorexant but increased the AUC0–inf. Exposure in elderly individuals was generally comparable to that in non‐elderly individuals. Altogether, vornorexant may have a favorable profile for insomnia treatment, including rapid onset of action and minimal next‐day residual effects.

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).

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Introduction TS-142 is a novel dual orexin receptor antagonist (DORA) developed for the treatment of insomnia. Here we report its pharmacokinetic profile in the healthy subjects and its efficacy and safety in patients with insomnia. Methods A phase1 study was conducted to clarify pharmacokinetic profile, in which various doses of TS-142 (1–30 mg) were orally administered once to thirty two healthy subjects. Subsequently, a phase 2a study utilizing polysomnography (PSG) was carried out in patients with primary insomnia, in which 5, 10, or 30 mg of TS-142, or placebo was randomly administered in a double-blind manner. Karolinska Sleepiness Scale (KSS) and Digit Symbol Substitution Test (DSST) were also examined in the morning after PSG. Results Following single administration of TS-142, plasma concentration of unchanged compound reached maximum within 2.50 h (median), and then eliminated rapidly, giving mean elimination half-life between 1.32 and 3.25 h. Twenty-three patients with insomnia completed the Phase2a study. Both latency to persistent sleep (LPS) and wake after sleep onset (WASO) were significantly improved with TS-142 at all doses, in comparison with placebo (-42, -42 and -45 for LPS [min] and -28, -35 and -55 for WASO [min] in 5, 10, 30 mg, respectively). KSS and DSST administered in the morning indicated no serious hangover effects. No serious adverse events were observed in these trials. Conclusion The phase 1 trial showed favorable pharmacokinetic profiles. The phase 2a trial demonstrated that TS-142 was efficacious in objective sleep onset and maintenance with minimal next-day residual effects. TS-142 was generally well tolerated in both studies. Support Taisho Pharmaceutical. Co., Ltd.