Oveporexton: Research & Studies
Scientific evidence, clinical trials, and research findings
๐TL;DR
- โข2 clinical studies cited
- โขOverall evidence level: high
- โข6 research gaps identified
Research Studies
Oveporexton, an Oral Orexin Receptor 2-Selective Agonist, in Narcolepsy Type 1
Dauvilliers Y, Plazzi G, Mignot E, et al. (2025) โข New England Journal of Medicine
Phase 2b randomized, placebo-controlled trial evaluating four dose regimens of oveporexton in 112 participants with narcolepsy type 1 over 8 weeks. All dose groups showed significant improvements in wakefulness, sleepiness, and cataplexy compared to placebo.
Key Findings
- MWT improvement: +12.5 to +25.4 minutes across dose groups vs -1.2 minutes placebo (all P<=0.001)
- ESS improvement: -8.9 to -13.8 points across dose groups vs -2.5 placebo (all P<=0.004)
- Significant reduction in weekly cataplexy rate at week 8
- Most common AEs: insomnia (48%), urinary urgency (33%), urinary frequency (32%)
- No hepatotoxicity or visual disturbances observed
Limitations: 8-week duration; relatively small sample size (n=112); no long-term efficacy or safety data in this publication; limited to narcolepsy type 1
TAK-861, a potent, orally available orexin receptor 2-selective agonist, produces wakefulness in monkeys and improves narcolepsy-like phenotypes in mouse models
Mitsukawa K, Terada M, Yamada R, et al. (2024) โข Scientific Reports
Preclinical pharmacology study characterizing TAK-861 as a potent OX2R agonist with EC50 of 2.5 nM and approximately 3000-fold selectivity over OX1R. Demonstrated wakefulness promotion in monkeys and narcolepsy symptom improvement in mouse models.
Key Findings
- OX2R EC50 of 2.5 nM with approximately 3000-fold selectivity over OX1R
- Approximately 10-fold more potent than TAK-994 (danavorexton)
- Dose-dependent wakefulness promotion at 1 mg/kg in mice and monkeys
- Ameliorated wakefulness fragmentation and cataplexy-like episodes in orexin-deficient mouse models
- Brain-wide neuronal activation pattern highly correlated with orexin-induced patterns
Limitations: Preclinical data only; animal models may not fully recapitulate human narcolepsy; pharmacokinetic translation to human dosing requires clinical confirmation
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๐Research Gaps & Future Directions
- โขLong-term efficacy and safety data beyond 12 weeks from controlled trials (extension study ongoing but not fully published)
- โขEfficacy in narcolepsy type 2, which has different pathophysiology with less complete orexin deficiency (Phase 3 trial underway)
- โขHead-to-head comparison with established narcolepsy treatments (sodium oxybate, pitolisant, modafinil)
- โขEffects on comorbid conditions common in narcolepsy (depression, anxiety, cognitive impairment)
- โขOptimal long-term dosing strategy and whether dose adjustments are needed over time
- โขPediatric narcolepsy type 1 population (not yet studied)
Research Overview#
Oveporexton (TAK-861) has a rapidly growing clinical evidence base, including a pivotal Phase 2b trial published in the New England Journal of Medicine (2025) and two positive Phase 3 trials (FirstLight and RadiantLight). The preclinical pharmacology is well characterized in a 2024 Scientific Reports publication. Collectively, these data establish oveporexton as a first-in-class OX2R-selective agonist with robust efficacy across the core symptoms of narcolepsy type 1.
The evidence level is classified as high based on a positive Phase 2b RCT published in a top-tier journal, two positive Phase 3 RCTs meeting all endpoints, and a well-characterized mechanism of action. FDA NDA acceptance with Priority Review further supports the strength of the evidence package.
Phase 2b Trial (NEJM 2025)#
The Phase 2b trial (Dauvilliers et al., NEJM 2025; PMID 40367374) was a randomized, double-blind, placebo-controlled study evaluating oveporexton in 112 participants with narcolepsy type 1.
Study Design#
- Population: Adults with confirmed narcolepsy type 1 (defined by ICSD-3 criteria including CSF hypocretin-1 deficiency)
- Randomization: 90 participants to oveporexton (four dose groups) and 22 to placebo
- Duration: 8 weeks of treatment
- Primary endpoint: Mean change from baseline to week 8 in average sleep latency on the Maintenance of Wakefulness Test (MWT)
- Secondary endpoints: Epworth Sleepiness Scale (ESS) total score, weekly cataplexy rate, adverse events
Efficacy Results#
All four oveporexton dose groups demonstrated statistically significant improvements over placebo:
Maintenance of Wakefulness Test (MWT):
- 0.5 mg BID: +12.5 minutes (P<=0.001)
- 2 mg BID: +23.5 minutes (P<=0.001)
- 2/5 mg QD: +25.4 minutes (P<=0.001)
- 7 mg QD: +15.0 minutes (P<=0.001)
- Placebo: -1.2 minutes
Epworth Sleepiness Scale (ESS):
- 0.5 mg BID: -8.9 points (P<=0.004)
- 2 mg BID: -13.8 points (P<=0.001)
- 2/5 mg QD: -12.8 points (P<=0.001)
- 7 mg QD: -11.3 points (P<=0.001)
- Placebo: -2.5 points
The 2 mg BID and 2/5 mg QD regimens produced the largest improvements across endpoints, informing dose selection for Phase 3.
Safety Profile#
The most common adverse events were insomnia (48%), urinary urgency (33%), and urinary frequency (32%). Most adverse events were mild to moderate, with onset within 1-2 days of treatment initiation and many resolving within the first week. No hepatotoxicity or visual disturbances were observed, distinguishing oveporexton from earlier OX2R agonists.
Phase 3 Trials (FirstLight and RadiantLight)#
FirstLight (TAK-861-3001)#
FirstLight was a global, multicenter, randomized, double-blind, placebo-controlled Phase 3 trial in 168 participants with narcolepsy type 1 across 19 countries. Participants were randomized to oveporexton 1 mg BID, 2 mg BID, or placebo for 12 weeks.
The trial met all primary and secondary endpoints:
- Statistically significant improvement in MWT at week 12 (P<0.001 for both doses)
- Statistically significant improvement in ESS (P<0.001)
- Significant reduction in weekly cataplexy rate (more than 80% median reduction)
- Majority of participants on 2 mg BID achieved normative MWT values (20 minutes or more)
- Approximately 85% of participants on 2 mg BID achieved ESS scores of 10 or less
RadiantLight (TAK-861-3002)#
RadiantLight was a global, multicenter, randomized, double-blind, placebo-controlled Phase 3 trial in 105 participants with narcolepsy type 1. Participants were randomized to oveporexton 2 mg BID or placebo for 12 weeks.
The trial met all primary and secondary endpoints, confirming the efficacy results from FirstLight.
Cataplexy-Free Days#
Across both Phase 3 trials, participants on oveporexton reported 4-5 cataplexy-free days per week at week 12, compared to none at baseline. This represents a meaningful functional improvement for patients whose daily activities are disrupted by unpredictable cataplexy episodes.
Preclinical Pharmacology (Scientific Reports 2024)#
The preclinical characterization of TAK-861 (Mitsukawa et al., 2024; PMID 39242684) established the pharmacological profile:
- Potency: EC50 of 2.5 nM at OX2R (calcium mobilization), approximately 10-fold more potent than TAK-994
- Selectivity: Approximately 3000-fold selectivity for OX2R over OX1R
- In vivo efficacy: Dose-dependent wakefulness promotion at 1 mg/kg in mice and cynomolgus monkeys
- Disease model efficacy: Amelioration of wakefulness fragmentation and cataplexy-like episodes in orexin/ataxin-3 and orexin-tTA;TetO DTA mouse models
- Neuronal activation: Brain-wide c-Fos activation pattern highly correlated with orexin-induced activation, suggesting engagement of endogenous wakefulness circuitry
- Comparison to modafinil: TAK-861 induced neuronal activation patterns more similar to orexin than modafinil, suggesting a more physiological wake-promoting mechanism
Cognition Secondary Analysis#
A secondary analysis of the Phase 2b trial published in JAMA Neurology examined the effects of oveporexton on cognitive function in narcolepsy type 1. Cognitive impairment is a recognized but often underappreciated aspect of NT1. Results showed improvements in attention and processing speed measures, suggesting that OX2R activation may benefit cognitive domains beyond wakefulness.
Regulatory Timeline#
| Date | Milestone |
|---|---|
| 2024 | Phase 2b results presented at SLEEP 2024 |
| May 2025 | Phase 2b trial published in NEJM |
| September 2025 | Phase 3 results presented at World Sleep 2025 |
| February 2026 | FDA accepts NDA with Priority Review |
| Q3 2026 | PDUFA target date |
Evidence Quality Assessment#
| Evidence Criterion | Assessment | Details |
|---|---|---|
| Study design | Phase 2b and Phase 3 RCTs | Double-blind, placebo-controlled |
| Sample size | Adequate | n=112 (Phase 2b), n=168 and n=105 (Phase 3) |
| Consistency | High | All trials met all endpoints at all doses |
| Primary endpoint | Objective | MWT (standardized sleep latency measure) |
| Publication | Top-tier | NEJM (Phase 2b); Phase 3 full publication pending |
| Regulatory status | NDA filed | Priority Review granted by FDA |
| Long-term data | Emerging | Extension study ongoing |
| Mechanism | Well-characterized | Preclinical pharmacology published in Scientific Reports |
Related Reading#
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