SINGAPORE & OSAKA, JAPAN & CAMBRIDGE, MASS. -- Takeda (TSE:4502/NYSE:TAK) presented data from two global Phase 3 double-blind, placebo-controlled studies of oveporexton (TAK-861)[1], a potential first-in-class investigational oral orexin receptor 2 (OX2R)-selective agonist in narcolepsy type 1 (NT1), during multiple oral presentations at the World Sleep 2025 Congress in Singapore beginning at 3:15 p.m. SGT On 8th Sept..

Both the FirstLight (TAK-861-3001) and RadiantLight (TAK-861-3002) studies met all primary and secondary endpoints demonstrating statistically significant improvement across a broad range of NT1 symptoms compared to placebo with p-values of <0.001 across all doses (twice-daily 1mg/twice-daily 2mg) at week 12. Oveporexton was generally well-tolerated with a safety profile consistent across clinical studies to date. No serious treatment-related adverse events were reported. The most common adverse events were insomnia, urinary urgency and frequency.

NT1 is a chronic, rare neurological disease caused by the loss of orexin neurons in the brain that results in a range of debilitating symptoms, which can severely impact every aspect of life. Currently, the standard available therapies only partially address some of the symptoms people face. As an orexin agonist, oveporexton is designed to fully address a broad range of NT1 symptoms by targeting the underlying orexin deficiency.

“Our research has shown that the loss of orexin is the cause of narcolepsy type 1, which results in symptoms like excessive daytime sleepiness and cataplexy,” said Dr. Emmanuel Mignot, M.D., Ph.D., principal investigator for the FirstLight Phase 3 study and one of the presenting authors. “Takeda’s groundbreaking efforts targeting the orexin receptor 2 in clinical studies led to positive Phase 3 results for oveporexton, bringing us a major step closer to having the first orexin therapy that addresses the underlying cause of narcolepsy type 1—with the potential of transforming the current treatment paradigm.”

Oveporexton was discovered in our Takeda labs. The Phase 3 oveporexton program is one of the largest, most comprehensive development programs for NT1. The studies investigated 14 primary and secondary endpoints over a total of 12 weeks in 273 patients across 19 countries. More than 95 percent of the participants who completed the studies enrolled in the ongoing long-term extension (LTE) study.

The oral presentations at World Sleep include data from objective and patient-reported measures of wakefulness, cataplexy, symptom severity and quality of life, including[2,3,4,5]:

· Wakefulness: Oveporexton improved excessive daytime sleepiness demonstrating statistically significant improvement from baseline in mean sleep latency on the Maintenance of Wakefulness Test (MWT) and in Epworth Sleepiness Scale (ESS) scores at week 12 across doses compared to placebo. The majority of participants treated with the 2/2mg dose achieved wakefulness within normative range (≥20 min) on the MWT, and close to 85 percent of participants achieved ESS scores comparable to healthy individuals (≤10).

· Cataplexy: Oveporexton demonstrated significant reduction in weekly cataplexy rate over 12 weeks across doses compared to placebo (median of percent change from baseline more than 80%). Median cataplexy free days compared to placebo improved from 0 days at baseline to 4-5 days per week at week 12. Cataplexy is a defining symptom for NT1 and is the sudden loss of muscle tone triggered by strong emotions.
Symptom Severity: Oveporexton showed statistically significant changes from baseline in the narcolepsy severity scale (NSS-CT) total score compared to placebo with more than 70 percent of participants reporting the lowest severity level (mild; score 0-14) across doses. Oveporexton also resulted in statistically significant improvements in overall narcolepsy symptoms as assessed by the self-rated Patient Global Impression of Change (PGI-C) scale with nearly all treated participants (97%) reporting improvements.

· Quality of Life: Oveporexton resulted in statistically significant improvements in quality of life reaching scores in the normative range as assessed by the Short Form-36-item (SF-36) survey. These outcomes were supported by significant improvements on exploratory endpoints including the EuroQol 5-Dimension 5-Level (EQ-5D-5L).

· Safety Profile: Across both studies, oveporexton was generally well-tolerated. No treatment-related serious adverse events were observed. Consistent with our experience from previous clinical studies, the most common adverse events were insomnia, urinary urgency and frequency. Most adverse events were mild to moderate.

“We are leveraging our leadership in orexin science and development with the aim to bring oveporexton to patients expeditiously in partnership with health authorities,” said Sarah Sheikh, M.Sc., B.M., B.Ch., MRCP, Head, Neuroscience Therapeutic Area Unit and Global Development at Takeda. “We are excited to share these transformative results at World Sleep, which demonstrate the potential for a new era of care defined by multiple treatment measures that matter to patients.”

Takeda will share other presentations during the World Sleep Congress in oral and poster sessions, including the impact of stigma on people with NT1, evaluations of sleep algorithms and orexin biomarkers for more accurate NT1 diagnosis and additional analyses from the oveporexton Phase 2b study, including patient satisfaction with treatment survey and impact on cognition, microsleeps and napping.

Results from the Phase 3 studies have no significant impact on the full year consolidated forecast for the fiscal year ending March 31, 2026.