Takeda Announces Positive Phase 3 Data for Oveporexton (TAK-861), a First-in-Class Oral OX2R Agonist for Narcolepsy Type 1

China Finance Network, September 8th – During the 2025 World Sleep Conference held in Singapore, Takeda Pharmaceutical Company Limited (TSE: 4502/NYSE: TAK) presented data from two global Phase 3 double-blind, placebo-controlled studies of Oveporexton (TAK-861) in multiple oral presentations starting at 3:15 PM local time.

Oveporexton is a potential first-in-class investigational oral selective orexin type 2 receptor (OX2R) agonist for the treatment of Type 1 Narcolepsy (NT1).

FirstLight (TAK-861-3001) and RadiantLight (TAK-861-3002) studies both met all primary and secondary endpoints. The results showed that, compared with placebo, a broad range of symptoms in type 1 narcolepsy achieved statistically significant improvement. At week 12, the p-values for all dose groups (1mg twice daily / 2mg twice daily) were <0.001. To date, Oveporexton has been generally well tolerated, with a consistent safety profile across clinical studies. No serious adverse events related to treatment have been reported. The most common adverse events were insomnia, urinary urgency, and urinary frequency.

Type 1 narcolepsy is a chronic, rare neurological disorder caused by the loss of orexin neurons in the brain, leading to a range of impaired physiological functions and potentially severely affecting all aspects of life. Currently, existing standard treatments can only alleviate some symptoms. Oveporexton, as an orexin agonist, aims to comprehensively address the broad clinical manifestations of type 1 narcolepsy by targeting the underlying orexin deficiency.

"Type 1 narcolepsy is characterized by symptoms such as excessive daytime sleepiness and cataplexy. Our research shows that its cause is orexin deficiency," said Dr. Emmanuel Mignot (M.D., Ph.D.), principal investigator of the FirstLight Phase 3 study and one of the conference presenters. Takeda Pharmaceutical Company Limited's work on orexin type 2 receptors in clinical research has yielded positive results for the Phase 3 study of Oveporexton, which is expected to become the first orexin therapy targeting the underlying cause of Type 1 narcolepsy, potentially transforming the current treatment paradigm.

Oveporexton was discovered by Takeda Pharmaceutical Company Limited. The Phase 3 clinical study of Oveporexton is one of the largest and most comprehensive clinical development programs for Type 1 narcolepsy, covering 273 patients across 19 countries, and evaluating 14 primary and secondary endpoints over 12 weeks. More than 95% of the participants have entered the long-term extension study.

The oral presentation at the World Sleep Congress includes data on objective and patient-reported awakenings, cataplexy, symptom severity, and quality of life metrics.

Sarah Sheikh, M.Sc., B.M., B.Ch., MRCP, Head of Neuroscience Research and Development at Takeda Pharmaceutical Company Limited, stated: "We are leveraging Takeda's leadership in orexin science and development to collaborate with health regulatory authorities, aiming to provide treatment for patients with Type 1 narcolepsy as soon as possible. We are thrilled to share the groundbreaking results of this study at the World Sleep Congress, showcasing its potential to usher in a new era of patient-centered, diversified treatment options."

Takeda Pharmaceutical Company Limited will share additional reports in oral and poster formats during the World Sleep Congress, including the impact of stigma on patients with type 1 narcolepsy, evaluation of sleep algorithms and orexin biomarkers (for more accurate diagnosis of type 1 narcolepsy), and further analyses from the Oveporexton Phase 2b study (including patient treatment satisfaction surveys and effects on cognition, microsleep, and napping).