Recruiting
Phase 1
Phase 2

ETX101

Sponsor:

Encoded Therapeutics

Code:

NCT05419492

Conditions

Dravet Syndrome

Eligibility Criteria

Sex: All

Age: 0 - 17

Healthy Volunteers: Not accepted

Interventions

ETX101

Study Details

Brief summary:

ENDEAVOR is a Phase 1/2, 2-part, multicenter study to evaluate the safety and efficacy of ETX101 in participants with SCN1A-positive Dravet syndrome aged ≥6 to <36 months (Part 1A), aged ≥48 months to <18 years (Part 1B), and aged ≥6 to <48 months (Part 2). Part 1A follows an open-label, dose-escalation design, Part 1B follows an open-label design, and Part 2 is a randomized, double-blind, sham delayed-treatment control study.

Conditions

Dravet Syndrome

Study ID

NCT05419492

Start date

May 14, 2024

Status verified date

Feb, 2026

Completion date

Jan, 2033

Anticipated

Primary completion date

Jan, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 0 - 17

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Participant must be aged between ≥6 months and <36 months in Part 1A, ≥48 months and <18 years in Part 1B, ≥6 months and <48 months in Part 2.
  • Participant must have a predicted loss of function pathogenic or likely pathogenic SCN1A variant.
  • Participant must have experienced their first seizure between the ages of 3 and 15 months.
  • Participant must have a clinical diagnosis of Dravet syndrome or the treating clinician must have a high clinical suspicion of a diagnosis of Dravet syndrome.
  • Participant is receiving at least one prophylactic antiseizure medication.

Exclusion Criteria:

  • Participant has another genetic mutation or clinical comorbidity which could potentially confound the typical Dravet phenotype.
  • Participant has a known central nervous system structural and/or vascular abnormality (indicated by an MRI or CT scan of the brain).
  • Participant has an abnormality that may interfere with CSF distribution and/or has an existing ventriculoperitoneal shunt.
  • Participant has received sodium channel blockers during the Pre-Dosing Seizure Period.
  • Participant has experienced seizure freedom for a period of 4 consecutive weeks within the 90-day period prior to informed consent.
  • Participant has previously received gene or cell therapy.
  • Participant is currently enrolled in a clinical trial or receiving an investigational therapy.
  • Participant has clinically significant underlying liver disease.

Study Design

Enrollment

47 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Part 1 (US Only)

Part 1A will follow an open-label, rule-based, dose-escalation design and will evaluate up to 4 dose levels of ETX101. Part 1B will follow an open-label design and will evaluate 1 dose level of ETX101.

sham comparator: Part 2

Part 2 will follow a double-blind (up through Week 52), randomized, sham delayed-treatment control design.

There will be 2 cohorts in Part 2. A single dose level of ETX101 will be evaluated in Part 2 and participants will be randomized 2:1 to study treatment or sham procedure with delayed treatment.

Interventions

ETX101

ETX101 is a non-replicating, recombinant adeno-associated viral vector serotype 9 (rAAV9) comprising a GABAergic regulatory element (reGABA) and an engineered transcription factor that increases transcription of the SCN1A gene (eTFSCN1A). ETX101 is intended as a one-time intracerebroventricular (ICV) administration.

Primary outcome measure

  • Percent change in monthly countable seizure frequency (MCSF) between the Pre-Dosing Seizure Period and the Post-Dosing Assessment Period. [ Time Frame: Between the Pre-Dosing Seizure Period and the Post-Dosing Assessment Period (defined as Week 5 to Week 52). ]

Central Contacts and Locations

Central contacts

Encoded Patient Advocacy

+1 (650) 398-4301patientadvocacy@encoded.com

Locations

UCSF Benioff Children's Hospitals

Recruiting

San Francisco, California, United States, 94158

Contacts

Adam Numis, MD

Adam.numis@ucsf.edu

Principal Investigator:

Adam Numis

Colorado Children's Hospital

Recruiting

Aurora, Colorado, United States, 80045

Contacts

Kallie Dock

720-777-5322Kallie.dock@childrenscolorado.org

Nicklaus Children's Hospital

Recruiting

Miami, Florida, United States, 33155

Contacts

Matt Lallas

305-662-8330Matt.Lallas@nicklaushealth.org

Dainelys Pena Rodriguez

786-624-3547Dainelys.PenaRodriguez@nicklaushealth.org

Ann & Robert H. Lurie Children's Hospital of Chicago

Recruiting

Chicago, Illinois, United States, 60611

Contacts

Jazmine Ibarra

312-227-0967jazibarra@luriechildrens.org

Principal Investigator:

Linda Laux

Mott Children's Hospital

Recruiting

Ann Arbor, Michigan, United States, 48109

Contacts

Stephanie Rau

734-232-8474shatchew@med.umich.edu

Mayo Clinic

Recruiting

Rochester, Minnesota, United States, 55905

Contacts

Bridget Neja

507-266-9150neja.bridget@mayo.edu

Duke Children's Hospital & Health Center

Recruiting

Durham, North Carolina, United States, 27705

Contacts

Makenzi Buchanan

919-613-1232Makenzi.hayes@duke.edu

Oregon Health and Science University (OSHU)

Recruiting

Portland, Oregon, United States, 97239

Contacts

Emily Stein

steine@ohsu.edu

Cook Children's Medical Center

Recruiting

Fort Worth, Texas, United States, 76104

Contacts

Dianna Grado, RN, CCRC

(682) 885-2844Dianna.Grado@cookchildrens.org

Principal Investigator:

Scott Perry

More Information

Sponsor

Encoded Therapeutics

Last update posted

Aug 21, 2026

Last verified

Feb, 2026

Keywords

  • Dravet
  • SCN1A
  • DEE
  • developmental and epileptic encephalopathy
  • Dravet Syndrome
  • SCN1A-positive
  • SCN1A+

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Encoded Therapeutics on 2026-08-21.