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XEN1101

Phase 3

Focal Epilepsy | Small molecule | Neurology |Xenon Pharmaceuticals Inc.|Last Updated: Sep 11, 2026

Target and mechanism

Molecular targetKv7
Target classPotassium Channel
ModalitySmall molecule

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials2
Total Enrollment1,205

FDA Designations

No designations recorded

Clinical trial landscape

XEN1101 · 6 trials · 5 indications

Phase 3 4Phase 2 2
NCT05716100A Randomized Study of XEN1101 Versus Placebo in Focal-Onset Seizures (X-TOLE3)Focal Onset Seizures
RECRUITING360 Analytics
NCT05718817An Open-label Study of XEN1101 in EpilepsyFocal Epilepsy
ENROLLING BY_INVITATION880 Analytics
NCT05667142A Study to Evaluate XEN1101 as Adjunctive Therapy in Primary Generalized Tonic-Clonic SeizuresPrimary Generalized Tonic-Clonic Seizures
RECRUITING160 Analytics
NCT05614063A Randomized Study of XEN1101 Versus Placebo in Focal-Onset SeizuresFocal Onset Seizures
COMPLETED380 Analytics
PHASE3RECRUITING
A Randomized Study of XEN1101 Versus Placebo in Focal-Onset Seizures (X-TOLE3)
Focal Onset SeizuresUnlock trial analytics
PHASE3ENROLLING BY_INVITATION
An Open-label Study of XEN1101 in Epilepsy
Focal EpilepsyUnlock trial analytics
PHASE3RECRUITING
A Study to Evaluate XEN1101 as Adjunctive Therapy in Primary Generalized Tonic-Clonic Seizures
Primary Generalized Tonic-Clonic SeizuresUnlock trial analytics
PHASE3COMPLETED
A Randomized Study of XEN1101 Versus Placebo in Focal-Onset Seizures
Focal Onset SeizuresUnlock trial analytics

Study Endpoints

Primary Endpoints

Median percent change (MPC) in focal seizure frequency from baseline to DBP for XEN1101 versus placebo.
From baseline through to the double blind period (week 12).
The adverse events
From the start of treatment in the open-label extension (OLE) study through 8 weeks after the last dose.

To assess the safety and tolerability of XEN1101

Median percent change (MPC) in monthly (28 days) PGTCS frequency
Baseline through DBP (Week 12)

Median percent change (MPC) in monthly (28 days) PGTCS frequency from baseline through the DBP for XEN1101 versus placebo.

Median percent change (MPC) in monthly (28 days) focal seizure frequency from baseline to DBP for XEN1101 versus placebo.
From baseline through to the double blind period (week 12)
Change in Montgomery-Åsberg Depression Rating Scale (MADRS) score.
From baseline to end of treatment (Week 6).
Frequency and severity of treatment-emergent adverse events (TEAEs), treatment-emergent serious adverse events (SAEs), and TEAEs leading to treatment discontinuations.
From randomization to Week 10.
Median Percent Change in Focal Seizure Frequency
From baseline (8 weeks prior to Day 0) through to the final dose (up to Day 56)

Median percent change in monthly (28 days) focal seizure frequency from baseline to DBP for XEN1101 versus placebo

Secondary Endpoints

Proportion of subjects experiencing ≥50% reduction in focal seizure frequency from baseline through the DBP for XEN1101 versus placebo.
From baseline through to the double blind period (week 12).
MPC in weekly (7 days) focal seizure frequency from baseline to Week 1 for XEN1101 versus placebo.
From baseline through to the week 1.
Proportion of subjects experiencing "at least much improved" (including "much" and "very much improved") in Patient Global Impression of Change (PGI-C).
From baseline through to the double blind period (week 12).
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
XEN1101 25 mg/dayEXPERIMENTALXEN1101 25 mg/day
XEN1101 15 mg/dayEXPERIMENTALXEN1101 15 mg/day
PlaceboPLACEBO_COMPARATORPlacebo
XEN1101 15 or 25 mg/dayEXPERIMENTALXEN1101 15 or 25 mg/day
XEN1101 10 mgEXPERIMENTALDuring the double blind treatment period (42 days), subjects will take 1 capsule of XEN1101 10 mg, orally with food, per day
XEN1101 20 mgEXPERIMENTALDuring the double blind treatment period (42 days), subjects will take 1 capsule of XEN1101 20 mg, orally with food, per day
25 mg XEN1101EXPERIMENTALCapsule filled with 25 mg XEN1101
20 mg XEN1101EXPERIMENTALCapsule filled with 20 mg XEN1101
10 mg XEN1101EXPERIMENTALCapsule filled with 10 mg XEN1101

Interventions

NameTypeDescription
XEN1101DRUGXEN1101 Capsules
PlaceboDRUGPlacebo Capsules
XEN1101 10 mgDRUGXEN1101 oral capsule
XEN1101 20 mgDRUGXEN1101 oral capsule
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites95

Inclusion Criteria: * Be properly informed of the nature and risks of the study and give informed consent in writing, prior to entering the study * Diagnosis (≥2 years) of focal epilepsy according to the International League Against Epilepsy (ILAE) Classification of Epilepsy (2017). Subject must ha...

Countries:United StatesArgentinaAustraliaAustriaBelgiumBulgariaChileCroatiaCzechiaFinlandFranceGermanyHungaryIsraelItalyMexicoNetherlandsPolandPortugalSpainCanadaGeorgiaIrelandNew ZealandUnited KingdomLatviaMoldovaUkraine
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Recent Changes (Last 90 Days)

LOWSep 11, 2026NCT05718817lastUpdatePostDate: changed
LOWSep 11, 2026NCT05718817lastUpdatePostDate: changed
LOWAug 11, 2026NCT05667142lastUpdatePostDate: changed
LOWAug 11, 2026NCT05718817lastUpdatePostDate: changed
LOWAug 11, 2026NCT05667142lastUpdatePostDate: changed
LOWAug 11, 2026NCT05718817lastUpdatePostDate: changed
LOWAug 11, 2026NCT05667142lastUpdatePostDate: changed
LOWAug 11, 2026NCT05718817lastUpdatePostDate: changed
LOWJul 8, 2026NCT05667142lastUpdatePostDate: changed
LOWJul 8, 2026NCT05718817lastUpdatePostDate: changed
LOWJul 8, 2026NCT05667142lastUpdatePostDate: changed
LOWJul 8, 2026NCT05718817lastUpdatePostDate: changed
MEDIUMJun 14, 2026NCT05614063TRIAL_REMOVED: changed
MEDIUMJun 14, 2026NCT05614063TRIAL_REMOVED: changed

Frequently asked questions about XEN1101

What is XEN1101 used for?

XEN1101 is an investigational small molecule being developed for focal epilepsy, focal onset seizures, primary generalized tonic-clonic seizures, and major depressive disorder. It is in Phase 3 clinical development and is not yet approved for any indication.

What does XEN1101 target?

XEN1101 targets Kv7 potassium channels. By modulating these channels, it is designed to regulate neuronal excitability, which is the basis for its development in seizure disorders and major depressive disorder.

Who is developing XEN1101?

XEN1101 is being developed by Xenon Pharmaceuticals Inc., which trades on the Nasdaq under the ticker XENE. The company is running multiple Phase 3 trials of XEN1101 in epilepsy indications.

What phase is XEN1101 in?

XEN1101 is in Phase 3 clinical development. It is investigational and has not been approved by the FDA. The Phase 3 program includes completed and ongoing trials in focal onset seizures and primary generalized tonic-clonic seizures.

What clinical trials is XEN1101 in?

XEN1101 is being studied in several Phase 3 trials, including NCT05718817 (open-label epilepsy study), NCT05716100 (X-TOLE3 in focal-onset seizures), NCT05667142 (adjunctive therapy in primary generalized tonic-clonic seizures), and NCT05614063 (completed focal-onset seizures study). Total enrollment across these trials is approximately 1,205 participants.