Takeda’s investigational orexin agonist oveporexton (TAK-861) demonstrated broad Phase 3 benefits across narcolepsy type 1, improving cognition, daily functioning, and nighttime sleep. The FDA is reviewing the NDA under Priority Review with a PDUFA date in Q3 2026.
Written By: Kirti Kumbar, M. Pharm (QA)
Reviewed By: Pharmacally Editorial Team
Takeda reported additional Phase 3 findings for oveporexton (TAK-861), an investigational oral orexin receptor 2 (OX2R)-selective agonist, demonstrating broad clinical benefits across narcolepsy type 1 (NT1). Data presented at the SLEEP 2026 annual meeting showed significant improvements in daily functioning, cognition, and nighttime sleep compared with placebo, extending previously reported positive Phase 3 efficacy results.
The findings come as oveporexton remains under regulatory review in the United States, Japan, and China. The FDA has granted Priority Review to the New Drug Application, with a Prescription Drug User Fee Act (PDUFA) target date expected in the third quarter of 2026.
Restoring Orexin Signaling in Narcolepsy
Narcolepsy type 1 is a chronic neurological disorder caused by the loss of orexin-producing neurons in the hypothalamus. The resulting orexin deficiency disrupts wakefulness regulation and contributes to excessive daytime sleepiness, cataplexy, fragmented nighttime sleep, hallucinations, sleep paralysis, and cognitive impairment.
Unlike currently available therapies that primarily manage individual symptoms, oveporexton activates orexin receptor 2 to restore orexin signaling. By addressing the underlying neurochemical deficit, the therapy has the potential to improve both daytime and nighttime manifestations of NT1.
Phase 3 Studies Show Broad Clinical Benefits
The new analyses were derived from two global, multicenter, placebo-controlled Phase 3 studies: FirstLight (TAK-861-3001, NCT06470828) and RadiantLight (TAK-861-3002, NCT06505031).
FirstLight enrolled 168 participants randomized to twice-daily oveporexton 2 mg, 1 mg, or placebo, while RadiantLight enrolled 105 participants assigned to twice-daily oveporexton 2 mg or placebo. Both studies evaluated efficacy, safety, and tolerability over 12 weeks.
Across all evaluated doses, oveporexton significantly improved daily functioning versus placebo at Week 12 (p<0.001), as measured by the Functional Impacts of Narcolepsy Instrument (FINI). Improvements were observed across all six domains assessed by the scale, including tiredness, cognitive functioning, cataplexy, social participation, everyday activities, and daily responsibilities. Most treated participants reached or exceeded published normative thresholds in these domains.
The therapy also demonstrated meaningful benefits on cognitive symptoms. Objective neuropsychological assessments showed improvements in attention, executive function, and memory. Patient-reported outcomes supported these findings, with approximately 70% of participants receiving oveporexton reporting no significant cognitive difficulties on the FINI cognitive function domain, compared with roughly 15% of placebo-treated participants.
Exploratory analyses further showed improvements in nighttime sleep quality. Most participants receiving oveporexton reported no hallucinations or sleep paralysis, while patients treated with the 2 mg twice-daily regimen experienced clinically meaningful reductions in disrupted nighttime sleep. Investigators also observed shifts in rapid eye movement (REM) sleep patterns toward those typically seen in healthy individuals.
Benefits Extend Beyond Sleepiness
Emmanuel Mignot, MD, PhD, principal investigator of the FirstLight study, noted that NT1 extends far beyond excessive daytime sleepiness and cataplexy. He emphasized that the observed improvements across cognitive function, sleep quality, daily functioning, and quality of life support a broader therapeutic impact of orexin restoration.
Takeda’s neuroscience leadership highlighted that the Phase 3 program was structured to evaluate the full disease burden of NT1, reflecting the multifaceted impact of orexin deficiency on patients’ daily lives.
Regulatory Review Continues
Additional analyses from the Phase 3 program will be presented at SLEEP 2026, including pooled efficacy data, evaluations of microsleep reduction, and further assessments of symptom burden in patients with NT1.
More than 95% of participants who completed FirstLight and RadiantLight enrolled in the ongoing long-term extension study, which will provide critical data on durability of response and long-term safety.
If approved, oveporexton would become the first orexin agonist available for narcolepsy type 1, introducing a mechanism-based treatment approach that could reshape disease management beyond symptomatic control.
Reference
Oveporexton Phase 3 Results Show Benefits for Narcolepsy Type 1 Symptoms
About the Writer
Kirti Kumbhar (LinkedIn) is an M.Pharm graduate with experience in Quality Assurance at Lupin Limited and a strong interest in clinical research, regulatory affairs, and Trial Master File (TMF) management. She has developed knowledge of regulatory documentation, quality systems, compliance, and healthcare research through her professional experience. Passionate about clinical development and continuous learning, Kirti is committed to supporting high-quality healthcare documentation, regulatory excellence, and research-driven healthcare advancements.