Takeda Reports Positive Phase 3 Results for Oveporexton in Narcolepsy Type 1

OSAKA, Japan and CAMBRIDGE, MA, USA – On July 14, 2025, Takeda (TSE:4502/NYSE:TAK) made a significant announcement regarding its investigational drug, oveporexton (TAK-861), which targets narcolepsy type 1 (NT1). The company revealed that its Phase 3 clinical trials, FirstLight and RadiantLight, successfully met all primary and secondary objectives. These studies confirm the drug's efficacy in enhancing various symptoms associated with NT1, a disorder stemming from the loss of orexin-producing neurons in the brain.

Oveporexton, an oral orexin receptor 2 (OX2R)-selective agonist, holds promise as a pioneering treatment option by directly addressing the root cause of orexin deficiency. This breakthrough was validated by Phase 3 trials, marking the first time this mechanism has shown such significant improvements in symptoms. Christophe Weber, Takeda's president and CEO, emphasized this milestone as a testament to the company's capabilities in developing innovative treatments for complex conditions like NT1. He highlighted Takeda's commitment to advancing orexin biology and establishing a robust orexin-focused drug portfolio, positioning the company for sustained growth.

The global Phase 3 trials, conducted across 19 countries, involved rigorous testing against a placebo and spanned a 12-week period. Both studies demonstrated statistically significant improvements in key symptoms, including wakefulness, excessive daytime sleepiness, and cataplexy. The trials further evaluated oveporexton's impact on participants' attention, quality of life, and daily functioning, revealing clinically meaningful results across the spectrum of symptoms.

Safety-wise, oveporexton was generally well-tolerated. The trials reported no serious adverse events linked to the treatment. Common side effects included insomnia and urinary issues. Impressively, over 95% of participants who completed the trials opted to continue into an ongoing long-term extension study.

Dr. Andy Plump, president of R&D at Takeda, expressed gratitude towards the patients, their families, and the medical teams involved in the trials. He noted that the studies progressed at an unprecedented pace, driven by the urgency to provide NT1 patients with a potential treatment. Dr. Plump highlighted that the comprehensive assessment of the Phase 3 trials builds upon transformative results seen in earlier studies, with most participants achieving near-normal symptom ranges by the end of the treatment period. This progress underscores the momentum within Takeda's late-stage pipeline, which aims to deliver substantial value to patients globally.

Takeda plans to present these findings at upcoming medical conferences and intends to file a New Drug Application with the U.S. Food and Drug Administration, as well as other global regulatory agencies, within the 2025 fiscal year. Importantly, the outcomes from these studies are not expected to alter Takeda's financial forecast for the fiscal year ending March 31, 2026.

Narcolepsy type 1 is a chronic neurological disorder characterized by symptoms such as excessive daytime sleepiness, cataplexy, disrupted nighttime sleep, and occasional hallucinations upon falling asleep or waking. The condition is attributed to the loss of orexin-producing neurons, which play a crucial role in regulating wakefulness and other cognitive functions. Existing treatments primarily address symptoms but do not tackle the underlying cause. Oveporexton, by selectively stimulating the OX2R, aims to mitigate the orexin deficiency, offering a comprehensive approach to treating both daytime and nighttime symptoms.

Takeda continues to lead in orexin science, with oveporexton as the flagship asset in its orexin-focused lineup. The drug has received Breakthrough Therapy designation for NT1-related excessive daytime sleepiness from the U.S. FDA and China's National Medical Products Administration. Takeda is also exploring additional orexin agonists for conditions with normal orexin levels, such as narcolepsy type 2 and idiopathic hypersomnia.