Eisai Co., Ltd. announced the launch of DAYVIGO (lemborexant) in China on August 18, 2025, marking the introduction of the first orexin receptor antagonist for insomnia treatment in the Chinese market. The in-house developed drug received regulatory approval on May 27, 2025, for treating adults with insomnia characterized by difficulties with sleep onset and/or sleep maintenance.
Novel Mechanism of Action
DAYVIGO represents a departure from conventional insomnia treatments through its unique mechanism of action. Unlike traditional benzodiazepines that act directly on sleepiness, DAYVIGO functions as a dual orexin receptor antagonist that inhibits orexin neurotransmission by binding competitively to both subtypes of orexin receptors (OX1R and OX2R). The drug regulates sleep-wake rhythm by suppressing hyperactive wakefulness rather than inducing sleepiness directly.
The compound demonstrates stronger inhibition effects on OX2R, which suppresses both REM and non-REM sleep drive. This selective binding profile may contribute to DAYVIGO's potential to provide faster sleep onset and better sleep maintenance for patients. The fast on/off receptor kinetics of lemborexant to orexin receptors may influence the drug's ability to facilitate improvements in sleep onset and maintenance with minimal morning residual effects.
Addressing Significant Medical Need
Insomnia affects approximately 15.0% of adults in China, translating to roughly 172.5 million people suffering from the condition. The disorder is characterized by difficulty falling asleep, staying asleep, or both despite adequate opportunity to sleep, occurring at least three times per week for at least one month. These sleep disturbances can lead to fatigue, difficulty concentrating, and irritability, significantly impacting patients' daytime function and quality of life.
Currently, mainstream prescription drugs for insomnia in China primarily consist of treatments that act directly on sleepiness, creating increasing demand for new treatment options with different mechanisms of action.
Clinical Development and Approval
Eisai's application for DAYVIGO approval in China was accepted in January 2024, supported by robust clinical evidence from multiple Phase 3 studies. The approval was based on outcomes from two pivotal global Phase 3 clinical studies (SUNRISE 1: NCT02783729 and SUNRISE 2: NCT02952820) conducted in approximately 2,000 adult patients with insomnia, as well as results from a China-specific Phase 3 clinical study (Study 311: NCT04549168).
Dosing and Administration
The recommended dosage of DAYVIGO is 5 mg taken once per night, immediately before going to bed, with at least 7 hours remaining before the planned time of awakening. The dose may be increased to a maximum of 10 mg based on individual patient needs.
Global Market Presence
DAYVIGO has established a significant international presence, with approvals for insomnia treatment in more than 25 countries including Japan, the United States, Canada, Australia, and various Asian countries. The China launch represents an important milestone in Eisai's global expansion strategy for this novel sleep medication.
The company aims to contribute to the restoration of daytime function and recovery for patients with insomnia by potentially delivering an active daytime life through fast sleep onset and good quality sleep, addressing the substantial unmet medical need in the Chinese market.
