Lemborexant Gains Regulatory Clearance in China, Marking Expansion of Eisai's Sleep Medicine Portfolio Across Asia-Pacific

Eisai Co., Ltd. revealed the regulatory approval of lemborexant—marketed as DAYVIGO—in China for treating insomnia characterized by sleep onset difficulties and sleep maintenance problems. The pharmaceutical firm intends to roll out this medication during the second quarter of fiscal year 2025, adding to the drug’s presence in 22 countries worldwide, including Australia and other Asia-Pacific nations.

Understanding the Mechanism: How DAYVIGO Works

DAYVIGO represents a dual orexin receptor antagonist, functioning by inhibiting orexin neurotransmission that governs the sleep-wake cycle. The medication operates through competitive binding to two orexin receptor subtypes—OX1R and OX2R—with particularly potent effects on OX2R. This mechanism addresses both REM and non-REM sleep pathways, enabling patients to experience faster sleep onset coupled with sustained sleep maintenance throughout the night.

The fast on/off kinetics of lemborexant at orexin receptors may facilitate quicker sleep initiation while minimizing residual effects upon waking, differentiating it from certain competing approaches in the insomnia treatment landscape.

Clinical Evidence Supporting Approval

Eisai’s regulatory submission, accepted in January 2024, drew upon robust clinical data from three Phase 3 studies involving approximately 2,000 adult insomnia patients. The SUNRISE 1 and SUNRISE 2 trials conducted globally demonstrated the drug’s efficacy, while Study 311 provided region-specific evidence from Chinese patient populations. This comprehensive database enabled regulatory authorities to make an informed approval decision.

The Scale of Insomnia in China: A Growing Health Concern

China faces a substantial insomnia burden among its adult population. Current epidemiological estimates place the prevalence at 15.0%, translating to approximately 172.5 million individuals experiencing sleep difficulties. Insomnia is clinically defined as persistent difficulty falling asleep, remaining asleep, or both—occurring at least three times weekly for a minimum of one month—leading to downstream consequences including daytime fatigue, concentration impairment, and mood disturbances.

The introduction of lemborexant in Australia and across the region represents an important therapeutic addition, as the medication has already demonstrated clinical value in Japan, the United States, Canada, and other markets.

Looking Forward: Global Expansion and Patient Impact

Eisai continues pursuing worldwide availability of DAYVIGO as a novel insomnia treatment option. The company’s strategic vision centers on enabling patients to reclaim daytime functionality and quality of life through improved sleep architecture—combining rapid sleep initiation with sustained sleep quality throughout the night.