Orexin receptor (repositioned)

Class

Dual orexin antagonist repositioned for AD-associated sleep disturbance

The orexin (hypocretin) system is a pair of neuropeptides, orexin-A and orexin-B, that act on two G-protein-coupled receptors, OX1R and OX2R, expressed in brain regions that govern arousal. Orexin neurons in the hypothalamus fire during wakefulness and quiet during sleep, acting as a stabilizing switch that keeps the brain in either a wake or a sleep state rather than drifting between the two. Dual orexin receptor antagonists block both receptor subtypes, dampening this wake-promoting signal and allowing sleep onset and maintenance without directly sedating other brain circuits the way older hypnotics do. This mechanism is being explored beyond primary insomnia in neurodegenerative disease, particularly Alzheimer's disease, where sleep-wake cycles become fragmented and nighttime wakefulness is common. Because sleep supports clearance of metabolic waste products, including amyloid-beta, in the brain, disturbed sleep architecture may accelerate underlying neurodegeneration, and improving sleep quality is hypothesized to have value beyond symptom relief alone. Repositioning a dual orexin antagonist for this population reflects the idea that correcting a shared upstream driver of poor sleep could benefit both daytime function and the broader disease trajectory, an area of active scientific interest rather than an established therapeutic pathway.