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A specimen of the Cognitive drawer Drawer E · Cognitive

Oveporexton

Investigational

A first-in-class oral orexin receptor 2 (OX2R) selective agonist developed by Takeda for narcolepsy type 1. Though not a peptide itself, oveporexton restores orexin peptide signaling lost due to autoimmune destruction of orexin-producing neurons. A Phase 2 trial (NEJM 2025) demonstrated significant reductions in excessive daytime sleepiness and cataplexy; Phase 3 trials are ongoing. Granted FDA Breakthrough Therapy designation.

TAK-861

Research evidence
Moderate

22 human studies

Preclinical
21%
Clinical
79%

Based on 28 cited sources

Evidence Score67/100
Emerging / moderate
Research Depth70/100
Mechanism91/100
Plausibility91/100
Global Coverage55/100
Community Experience12/100
Effectiveness74/100

clinically demonstrated · moderate confidence

Demonstrated effect magnitude — not a recommendation or safety claim.

Research Depth 70: best verified human evidence is a single adequately-powered, double-blind, placebo-controlled multicenter Phase 2 RCT (Dauvilliers et al., NEJM 2025, PMID 40367374, NCT05687903, n=112) — 1A=28 (single RCT n>=50; the real Phase 3 trials NCT06470828/NCT06505031 are completed but not yet published, so Phase 3 efficacy is not credited), 1B=15 (low-RoB RCT, no systematic review yet), 1C=6 (total human N ~112, 50-300 band), 1D=13 (direct: NT1 population, oral route, MWT/ESS/cataplexy outcomes), 1E=8 (substantial multi-model preclinical foundation: orexin and OX2R knockouts PMID 10481909 / 12797957, discovery work PMID 9491897). Mechanism 91: OX2R is a named target with binding + functional confirmation and OX2R-knockout dissection of the wake effect (2A=40), full Gq/11 -> arousal-center pathway mapped (2B=26), dose-response across human dose groups and in-vivo models (2C=15), confirmed in vivo (2D=10). Plausibility 91: full mechanism -> surrogate (MWT/ESS) -> clinical outcome (cataplexy) chain (3A=34), restoring the exact deficient orexin signal is textbook NT1 pathophysiology (3B=25), same-class OX2R agonists danavorexton/TAK-994 show the analogous effect (3C=18), tightly scoped single-indication claim (3D=14). Global Coverage 55: pivotal data from one sponsor program (Takeda) replicated for the class across groups (4A=18), Phase 2 multinational across ~7 countries (4B=20), modest compound-specific literature ~28 sources (4C=12), FDA Breakthrough Therapy + registered ongoing Phase 3 but no approval yet (4D=5). Community Experience 12: investigational, not marketed, no meaningful documented real-world use or longevity (5A=3,5B=3,5C=2,5D=4). Effectiveness 74 (clinical, moderate confidence): Phase 2 RCT showed large, MCID-exceeding effects — MWT average sleep latency +25.4 min vs -1.2 placebo and ESS -13.8 vs -2.5 (E1=27, E2=22), validated patient-relevant wakefulness/cataplexy endpoints (E3=12), superior to placebo on clinical outcomes with no head-to-head vs sodium oxybate (E4=13); confidence moderate as evidence rests on one Phase 2 trial with Phase 3 pending.

Scored June 2026 How we rate →
~
Evidence Level
moderate
Not approved for human use by any regulatory agency
Limited human clinical trial data
Consult a healthcare provider before use
Not FDA Approved WADA Prohibited
Identity
SCALE · 1:1 N-TERMINUS C-TERMINUS ~450-550 Da (estimated)
Also Known As
TAK-861
Class
Small molecule OX2R agonist
Length
0 amino acids
Mol. weight
~450-550 Da (estimated)
Sequence
N/A (small molecule)
Molecular Structure
Hydrophobic
Polar
Positive
Negative

Oveporexton is a first-in-class selective orexin receptor 2 (OX2R) agonist that restores the missing orexin signal in narcolepsy type 1 patients.

How It Works (Simplified)

Oveporexton replaces the missing orexin signal through targeted receptor activation:

OX2R Activation

Selectively binds and activates orexin receptor 2 in key arousal centers, mimicking the effect of endogenous orexin peptides.

Arousal Network

Activates wake-promoting neurons in TMN, locus coeruleus, and VTA, releasing histamine, norepinephrine, and dopamine.

Sleep-Wake Stability

Restores clear boundaries between sleep and wakefulness, reducing inappropriate sleep intrusions during the day.

Cataplexy Control

Suppresses REM sleep intrusions that cause cataplexy, the sudden muscle weakness triggered by emotions in NT1.

Key Research: Sakurai et al. (Cell 1998) discovered orexins and their receptors. PMID:9491897

Important Limitations

  • Oveporexton is NOT a peptide; it is a small molecule that modulates the orexin peptide system
  • Currently investigational - not yet approved by FDA or other regulatory agencies
  • Efficacy in narcolepsy type 2 (normal CSF orexin) is still being evaluated
  • Long-term safety data beyond clinical trial duration is pending
  • Head-to-head comparative trials vs sodium oxybate not yet completed
i. OX2R-Gq/11 Signaling Pathway · Wake Promotion
OveporextonOX2R bindingGq/11 activationPLCIP3 + DAGCa2+ release + PKCNeuronal depolarization
ii. Arousal Center Cascade · Neurotransmitter Release
OX2R activationTMN (histamine) + LC (norepinephrine) + VTA (dopamine)Stable wakefulness
Mechanism Selective OX2R agonism activating arousal centers (TMN, LC, VTA)
Established 12 direct studies
Benefit shown to reduce excessive daytime sleepiness in narcolepsy type 1
Evidence Level
High
8 Human
4 Animal
2 In Vitro
Mechanism Restoration of orexin signaling stabilizing sleep-wake boundaries
Established 10 direct studies
Benefit shown to reduce cataplexy attacks in narcolepsy type 1
Evidence Level
High
6 Human
4 Animal
Mechanism OX2R activation in tuberomammillary nucleus enhancing histaminergic arousal
Established 8 direct studies
Benefit shown to improve objective wakefulness on Maintenance of Wakefulness Test
Evidence Level
High
4 Human
6 Animal
2 In Vitro
Mechanism G-protein coupled receptor signaling via Gq/11 pathway
Established 15 direct studies
Benefit shown to address root pathophysiology of narcolepsy type 1
Evidence Level
High
3 Human
8 Animal
6 In Vitro
Mechanism Confidence
Established
Supported
Emerging
Evidence Level
High
Moderate
Low
Very Low
Phase 01 1
Week 1-2

Based on Phase 2 data: Rapid onset of wake-promoting effects. Patients may notice reduced daytime sleepiness within first weeks. Cataplexy frequency begins to decrease.

NCT05687903
Phase 02 2
Week 2-4

Continued improvement in wakefulness measures. Phase 2 endpoints assessed at multiple timepoints showed progressive benefit. Optimal steady-state drug levels achieved.

NCT05687903
Phase 03 3
Week 4-8

Full therapeutic effects observed in the Phase 2 trial. ESS improvements stabilize and weekly cataplexy rate is significantly reduced vs placebo through week 8.

NCT05687903
Phase 04 4
Week 8+

Long-term extension study (NCT05816382) ongoing to assess durability. Safety monitoring continues. Phase 3 trials completed in 2025 with results pending publication.

NCT05816382

Research-based observations

This timeline reflects observations from published clinical and preclinical studies. Individual responses may vary significantly. This is not a guarantee of effects or a dosing schedule. Consult qualified healthcare providers for personalized guidance.

Good Signs (5 indicators)
Pharmaceutical-grade product from licensed manufacturer (once approved)
Proper packaging with lot number and expiration date
Clear prescribing information from healthcare provider
Obtained through legitimate pharmacy channels
Consistent tablet or capsule appearance per manufacturer specifications
Warning Signs (4 indicators)
Product obtained outside of regulated pharmaceutical supply chain
Compounded formulation without proper quality assurance
Missing or inconsistent lot numbers
Packaging that appears tampered with or non-authentic
Bad Signs (5 indicators)
Product sold as 'research chemical' without regulatory approval
No verifiable manufacturer or source information
Obtained from unregulated online sources
Claims of identical efficacy at significantly lower cost from unknown sources
Any product claiming to be oveporexton before regulatory approval
Positive quality indicator
Requires evaluation
Potential quality issue

For Research Evaluation Only

These quality indicators are general guidelines based on typical peptide characteristics. Professional laboratory testing (HPLC, mass spectrometry) provides definitive quality verification. This checklist is for initial visual evaluation only.

Synergistic
Compatible
Caution
Avoid

Oveporexton mimics the endogenous orexin peptide signal at OX2R. In narcolepsy type 1, where orexin-A is deficient, oveporexton provides replacement receptor activation.

Orexin-B preferentially activates OX2R, the same target as oveporexton. The drug compensates for lost orexin-B signaling in NT1 patients.

Different wake-promoting mechanisms (dopamine/NE modulation vs OX2R agonism). May be used in combination, though oveporexton alone may be sufficient.

H3 receptor antagonist with different mechanism. Potential for complementary wake promotion, though clinical combination data is limited.

Suvorexant is a dual orexin receptor antagonist (DORA) used for insomnia. Concurrent use would cause direct pharmacological antagonism, negating therapeutic effects.

Lemborexant is a DORA for insomnia. Combining with oveporexton would result in opposing receptor effects and is contraindicated.

Research Note: Interaction data is based on published literature, mechanistic understanding, and theoretical considerations. Most peptide combinations lack direct clinical study. This information is for educational purposes only and does not constitute medical advice. Always consult qualified healthcare providers.

This dossier synthesizes available evidence from peer-reviewed literature, regulatory documents, and clinical trial registries. Evidence strength ratings follow a modified GRADE approach.

For complete methodology details, see our Methodology page.

Important Disclaimer

This dossier is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making health decisions.

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