Orexin receptor 2 agonists: a pathophysiologic approach to narcolepsy type 1.

Narcolepsy type 1 (NT1) is a chronic neurological disorder characterized by excessive daytime sleepiness, cataplexy, and disturbed nocturnal sleep, resulting from the loss of hypothalamic neurons that produce orexin. Current therapies, including stimulants, antidepressants, and sodium oxybate, primarily offer symptomatic relief without addressing the underlying orexin deficiency and often have safety or adherence limitations. Orexin receptor 2 (OX2R) agonists represent a novel therapeutic strategy aimed at restoring physiological wakefulness by directly targeting the core neurochemical deficit. TAK-994, the first oral OX2R agonist, demonstrated remarkable efficacy in reducing cataplexy and improving wakefulness but was discontinued due to dose-dependent hepatotoxicity. TAK-861 (oveporexton), a next-generation OX2R agonist with improved structural properties, has shown encouraging Phase 2 results with comparable efficacy and a favorable safety profile, including minimal hepatic effects and once-daily dosing convenience. If validated in large-scale Phase 3 studies, TAK-861 could become the first disease-modifying therapy for NT1, representing a paradigm shift from symptomatic management to mechanism-based treatment. The ongoing development of OX2R agonists highlights a promising frontier in precision sleep medicine, offering renewed hope for patients by targeting orexin restoration.