Orexin 2 receptor‐selective agonist danavorexton (<scp>TAK</scp>‐925) promotes wakefulness in non‐human primates and healthy individuals

<jats:title>Summary</jats:title><jats:p>The orexin 2 receptor‐selective agonist danavorexton (TAK‐925) has been shown to produce wake‐promoting effects in wild‐type mice, narcolepsy‐model mice, and individuals with narcolepsy type 1 and type 2. Here, we report wake‐promoting effects of danavorexton in non‐human primates and healthy men during their sleep phase. Electroencephalogram analyses revealed that subcutaneous administration of danavorexton significantly increased wakefulness in common marmosets (<jats:italic>p</jats:italic> < 0.05 at 0.1 mg kg<jats:sup>−1</jats:sup>, and <jats:italic>p</jats:italic> < 0.001 at 1 mg kg<jats:sup>−1</jats:sup> and 10 mg kg<jats:sup>−1</jats:sup>) and cynomolgus monkeys (<jats:italic>p</jats:italic> ≤ 0.05 at 1 mg kg<jats:sup>−1</jats:sup> and 3 mg kg<jats:sup>−1</jats:sup>). In a phase 1b crossover, randomized, double‐blind, placebo‐controlled and active‐controlled study in sleep‐deprived healthy participants (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://clinicaltrials.gov">ClinicalTrials.gov</jats:ext-link> identifier: NCT03522506), modafinil 300 mg (used to demonstrate assay sensitivity) and continuous infusion of danavorexton 44 mg and danavorexton 112 mg showed statistically superior wake‐promoting effects to placebo (<jats:italic>n</jats:italic> = 18). Measured using the Maintenance of Wakefulness Test, mean (standard deviation) sleep latencies during infusion of danavorexton 44 mg, danavorexton 112 mg and placebo were 21.4 (8.9), 31.8 (3.2) and 9.2 (6.4) min, respectively. Least‐squares mean difference from placebo in average sleep latency was 16.8 min with danavorexton 44 mg and 30.2 min with danavorexton 112 mg (both <jats:italic>p</jats:italic> < 0.001). Karolinska Sleepiness Scale scores were statistically significantly lower (indicating decreased sleepiness) for participants receiving danavorexton than for those receiving placebo during infusion (danavorexton 44 mg, <jats:italic>p</jats:italic> = 0.010; danavorexton 112 mg, <jats:italic>p</jats:italic> < 0.001). Together, these results indicate that an orexin 2 receptor agonist increases wakefulness in non‐human primates and healthy individuals during their sleep phase.</jats:p>