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TAK-861

Phase 3

Narcolepsy Type 1 | Small molecule | Neurology |Takeda Pharmaceutical Company Limited|Last Updated: Sep 1, 2026

Target and mechanism

Molecular targetOX2R
Target classReceptor
ModalitySmall molecule

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials4
Total Enrollment885

FDA Designations

No designations recorded

Clinical trial landscape

TAK-861 · 6 trials · 4 indications

Phase 3 3Phase 2 3
NCT07363720A Trial of TAK-861 for the Treatment of Narcolepsy With CataplexyNarcolepsy Type 1 (NT1)
ACTIVE NOT_RECRUITING98 Analytics
NCT06505031A Study of TAK-861 in People With Narcolepsy Type 1Narcolepsy Type 1
COMPLETED105 Analytics
NCT06470828A Study of TAK-861 for the Treatment of Narcolepsy Type 1Narcolepsy Type 1
COMPLETED168 Analytics
PHASE3ACTIVE NOT_RECRUITING
A Trial of TAK-861 for the Treatment of Narcolepsy With Cataplexy
Narcolepsy Type 1 (NT1)Unlock trial analytics
PHASE3COMPLETED
A Study of TAK-861 in People With Narcolepsy Type 1
Narcolepsy Type 1Unlock trial analytics
PHASE3COMPLETED
A Study of TAK-861 for the Treatment of Narcolepsy Type 1
Narcolepsy Type 1Unlock trial analytics

Study Endpoints

Primary Endpoints

Time to Loss of Response in the Epworth Sleepiness Scale (ESS) Score During the Up to 4-Week RW Period
Up to 4-week RW period

The ESS provides individuals with 8 different situations of daily life and asks them how likely they are to fall asleep in those situations (scored 0 to 3) and to try to imagine their likelihood of dozing even if they have not actually been in the identical situation; the scores are summed to give an overall score of 0 to 24. Higher scores indicate stronger subjective daytime sleepiness, and scores below 10 are considered to be within normal range.

Change From Baseline to Week 12 in Mean Sleep Latency From the Maintenance of Wakefulness Test (MWT) Wake Trials
Baseline, Week 12

The MWT evaluates a person's ability to remain awake under soporific conditions for a defined period of time. Because there is no biological measure of wakefulness, wakefulness is measured indirectly by the inability or delayed tendency to fall asleep. This tendency to fall asleep is measured via electroencephalography-derived sleep latency in the MWT. The MWT consists of four 40-minute sessions (trials) done 2 hours apart. Sleep latency in each session was recorded. Participants were required to stay awake in between the four sessions. A positive change from baseline indicates an improvement. The linear MMRM was used for analysis.

Change From Baseline to Week 12 in ESS Total Score
Baseline, Week 12

The ESS provides individuals with 8 different situations of daily life and asks them how likely they are to fall asleep in those situations (scored 0 to 3) and to try to imagine their likelihood of dozing even if they have not actually been in the identical situation; the scores are summed to give an overall score of 0 to 24. Higher scores indicate stronger subjective daytime sleepiness. A negative change from baseline indicates an improvement. The linear mixed effects model for repeated measures (MMRM) was used for analysis.

Change From Baseline to Week 12 in Mean Sleep Latency From the 4 Maintenance of Wakefulness Test (MWT) Wake Trials
Baseline, Week 12

The MWT evaluates a person's ability to remain awake under soporific conditions for a defined period of time. Because there is no biological measure of wakefulness, wakefulness is measured indirectly by the inability or delayed tendency to fall asleep. This tendency to fall asleep is measured via electroencephalography-derived sleep latency in the MWT. The MWT consists of four 40-minute sessions (trials) done 2 hours apart. Sleep latency in each session was recorded. Participants were required to stay awake in between the four sessions. A positive change from baseline indicates an improvement. The linear mixed effects model for repeated measures (MMRM) was used for analysis.

Number of Participants With at Least One or More Treatment-emergent Adverse Events (TEAEs)
From signing the informed consent form up to follow-up of 4 weeks after the last dose (Up to approximately 5 years)

An adverse event (AE) is defined as any untoward medical occurrence in a clinical investigation participant administered a drug; it does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (e.g., a clinically significant abnormal laboratory finding), symptom, or disease temporally associated with the use of a drug, whether or not it is considered related to the drug. A TEAE is defined as an adverse event with an onset that occurs after receiving trial intervention.

Change From Baseline in the Average Sleep Latency as Determined From the MWT at Week 8
Baseline, Week 8

The MWT is a validated, objective measure that evaluates a participant's ability to remain awake under soporific conditions for a defined period. During each MWT session (1 session = 40 minutes), participants were instructed to sit quietly and remain awake for as long as possible. Sleep latency in each session was recorded on EEG. If no sleep was observed according to these rules, then the latency was defined as 40 minutes. The linear mixed effects model for repeated measures (MMRM) was used for analysis.

Secondary Endpoints

Change From the End of the OL Treatment Period to Week 2 of the RW Period on the Maintenance of Wakefulness Test (MWT)
From the end of the OL treatment period (Week 16) to Week 2 of the RW period (Week 18)
Weekly Cataplexy Rate (WCR) at Week 2 of the RW Period
Week 2 of the RW period
Change from the End of the OL Treatment Period to Week 2 of the RW Period in Mean Number of Lapses on the Psychomotor Vigilance Test (PVT)
From the end of the OL treatment period (Week 16) to Week 2 of the RW period (Week 18)
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Double-blind RW Period: TAK-861EXPERIMENTALParticipants on stable TAK 861 dose will receive the same dose of TAK-861 they were taking at the end of the OL treatment period, for up to 4 weeks in the double-blind RW period.
Double-blind RW Period: PlaceboPLACEBO_COMPARATORParticipants will receive TAK-861 matching-placebo, for up to 4 weeks in the double-blind RW period.
PlaceboPLACEBO_COMPARATORParticipants received oveporexton matching placebo tablets, orally, twice daily (BID) for 12 weeks.
TAK-861EXPERIMENTALParticipants received oveporexton tablets, 2 milligrams (mg), orally, BID for 12 weeks.
OVE 1 mg BIDEXPERIMENTALParticipants received OVE tablets, 1 milligram (mg), orally, for 12 weeks.
OVE 2 mg BIDEXPERIMENTALParticipants received OVE tablets, 2 mg, orally, for 12 weeks.
TAK-861 0.5 mg BIDEXPERIMENTALParticipants received TAK-861 0.5 milligrams (mg), orally, BID, from Days 1 to 56.
TAK-861 2 mg BIDEXPERIMENTALParticipants received TAK-861 2 mg, orally, BID, from Days 1 to 56.
TAK-861 2 mg and 5 mgEXPERIMENTALParticipants received TAK-861 2 mg followed by 5 mg dose, orally, BID, from Days 1 to 56.
TAK-861 7 mg QDEXPERIMENTALParticipants received TAK-861 7 mg, orally, once daily (QD), from Day 1 to 56. Placebo was given as the second dose.
TAK-861 2 milligrams (mg) BIDEXPERIMENTALParticipants received TAK-861 2 mg, orally, BID, from Days 1 to 56.

Interventions

NameTypeDescription
TAK-861DRUGTAK-861 tablets
PlaceboDRUGTAK-861-matching placebo tablets
OveporextonDRUGOral tablet.
TAK-861 2 mgDRUGTAK-861 2 mg tablets.
TAK-861 2 mg and 5 mgDRUGTAK-861 2 mg and 5 mg tablets.
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Eligibility Criteria

Age Range16 Years to 70 Years
SexALL
Healthy VolunteersNo
Study Sites25

Inclusion Criteria: 1. The participant has a body mass index (BMI) within the range 18 to 40 kilograms per square meter (kg/m\^2). 2. The participant has an International Classification of Sleep Disorders, Third Edition (ICSD-3) or International Classification of Sleep Disorders, Third Edition, Tex...

Countries:United StatesFranceGermanyItalyNetherlandsSpainSwitzerlandAustraliaAustriaBelgiumChinaFinlandPolandSouth KoreaSwedenCanadaJapanNorwayUnited Kingdom
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Recent Changes (Last 90 Days)

MEDIUMSep 1, 2026NCT07363720Status: RECRUITING → ACTIVE_NOT_RECRUITING
MEDIUMSep 1, 2026NCT07363720Status: RECRUITING → ACTIVE_NOT_RECRUITING
MEDIUMAug 16, 2026NCT06505031TRIAL_REMOVED: changed
MEDIUMAug 16, 2026NCT06505031TRIAL_REMOVED: changed
MEDIUMAug 16, 2026NCT06505031TRIAL_REMOVED: changed
MEDIUMAug 16, 2026NCT06505031TRIAL_REMOVED: changed
LOWJul 8, 2026NCT07363720lastUpdatePostDate: changed
LOWJul 8, 2026NCT07363720lastUpdatePostDate: changed

Frequently asked questions about TAK-861

What is TAK-861 used for?

TAK-861 is an investigational small molecule being developed for the treatment of narcolepsy, specifically Narcolepsy Type 1 (NT1) and Narcolepsy Type 2. It is being studied in clinical trials for these conditions, including a Phase 3 trial for narcolepsy with cataplexy.

What does TAK-861 target?

TAK-861 targets the orexin 2 receptor (OX2R), a receptor involved in regulating wakefulness and sleep. By acting on this receptor, the drug is being investigated as a potential treatment for narcolepsy types 1 and 2.

Who makes TAK-861?

TAK-861 is being developed by Takeda Pharmaceutical Company Limited, a global biopharmaceutical company listed on the stock exchange under the ticker TAK. Takeda is conducting clinical trials to evaluate the drug's safety and efficacy in narcolepsy.

What phase is TAK-861 in?

TAK-861 is currently in Phase 3 clinical development for narcolepsy. It has completed Phase 2 trials in Narcolepsy Type 1 and Type 2, and a Phase 3 trial in Narcolepsy Type 1 has also been completed. An additional Phase 3 trial is active but not recruiting participants.

What clinical trials is TAK-861 in?

TAK-861 has been studied in four clinical trials. Completed trials include NCT05687903 (Phase 2, Narcolepsy Type 1), NCT05687916 (Phase 2, Narcolepsy Type 2), and NCT06505031 (Phase 3, Narcolepsy Type 1). An active Phase 3 trial, NCT07363720, is investigating TAK-861 for narcolepsy with cataplexy.

Is TAK-861 the same as a drug for narcolepsy with cataplexy?

TAK-861 is being studied for narcolepsy with cataplexy, which is a symptom of Narcolepsy Type 1. The active Phase 3 trial NCT07363720 specifically enrolls participants with narcolepsy with cataplexy, and the drug is also being evaluated in broader Narcolepsy Type 1 and Type 2 populations.