Business Wire·Aug 24, 2026, 2:36 AM ET

ORZEYFUL (oveporexton) Approved in Japan as the First and Only Medicine to Treat the Underlying Cause of Narcolepsy Type 1

Takeda received approval from Japan's Ministry of Health, Labour and Welfare (MHLW) for ORZEYFUL (oveporexton) to treat narcolepsy type 1 (NT1) in adults.
ORZEYFUL is the first oral orexin receptor 2 (OX2R) agonist approved in Japan, marking the third major regulatory approval for the drug globally following endorsements in China and the United States.
The medication targets the underlying orexin deficiency associated with NT1 rather than managing individual symptoms, offering potential improvements across the full range of disease manifestations including excessive daytime sleepiness, cataplexy, disrupted nighttime sleep, sleep paralysis, hallucinations, and cognitive issues.
Approval was based on global Phase 3 clinical trials (FirstLight and RadiantLight) which demonstrated statistically significant improvements in symptoms with a safety profile consistent with previous studies.
Common adverse events reported in clinical trials included insomnia, urinary urgency, urinary frequency, and excessive saliva.
The recommended adult dosage in Japan is 1mg administered orally twice daily, with a potential increase to 2mg twice daily if well-tolerated and efficacy is insufficient.
Oveporexton was discovered and developed internally by Takeda's laboratories in Japan, representing the first validation of the company's broader orexin strategy.
In the United States, the controlled substance classification for ORZEYFUL is currently under review by the Drug Enforcement Administration (DEA).