The U.S. Food and Drug Administration (FDA) grants Fast Track designation to Lu AH69593, an investigational oral orexin 2 receptor agonist being developed by Lundbeck for the treatment of narcolepsy. The orexin 2 receptor is described by the sponsor as part of a biological pathway involved in wakefulness and the regulation of the sleep-wake cycle. Fast Track is a regulatory program intended to facilitate the development and review of therapies that are meant to address serious conditions and meet specific criteria. The designation applies to Lu AH69593 for use in patients with narcolepsy, according to the announcement. The sources provided do not include trial results, specific study designs, timelines, or additional FDA decisions beyond the Fast Track status. The information focuses on the regulatory designation and the proposed biological mechanism associated with the orexin 2 receptor and sleep-wake regulation.