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NCT Number: NCT05419492

A Clinical Study to Evaluate the Safety and Efficacy of ETX101 in Infants and Children With SCN1A-Positive Dravet Syndrome

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.

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Key information

Conditions

Dravet Syndrome Brain Diseases Central Nervous System Diseases Epilepsies, Myoclonic Epilepsy Epilepsy, Generalized Epileptic Syndromes Generalized Epilepsy With Febrile Seizures Plus, Type 2 Nervous System Diseases

Age range

6 month–17 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1 / Phase 2

Primary location

The Royal Children's Hospital, Melbourne, Australia

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

ETX101

Drug

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 outcomes

  1. 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).

Secondary outcomes

  1. Change from Baseline in Bayley-4 cognitive subdomain raw score at Week 52 (Key Secondary Endpoint for Part 2).

    Time frame: From Baseline to Week 52.

  2. Change from Baseline in Vineland-3 subdomain GSVs at Week 52.

    Time frame: From Baseline to Week 52.

  3. Change from Baseline in Bayley-4 subdomain GSVs at Week 52.

    Time frame: From Baseline to Week 52.

  4. Proportion of participants achieving ≥ 75% reduction in 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).

  5. Proportion of participants achieving ≥ 50% reduction in 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).

  6. Change from Baseline in the Vineland-3 Adaptive Behavior Composite standard score at Week 52.

    Time frame: From Baseline to Week 52.

  7. Change from Baseline in Vineland-3 subdomain raw scores at Week 52.

    Time frame: From Baseline to Week 52.

  8. Change from Baseline in Bayley-4 subdomain raw scores (excluding cognitive subdomain) at Week 52.

    Time frame: From Baseline to Week 52.

  9. Proportion of CGI-I responders, defined as participants with a CGI-I score of 1 (Very much improved) or 2 (Much improved), at Week 52.

    Time frame: From Baseline to Week 52.

  10. Proportion of CGI-S responders, defined as participants who either have a CGI-S score of 1 (Normal, not at all ill) or demonstrate a ≥2 point improvement from Baseline, at Week 52.

    Time frame: From Baseline to Week 52.

Other outcomes

  1. Safety Endpoint: Proportions of participants experiencing any treatment-emergent DLTs (for Part 1A only), AEs, serious adverse events (SAEs), related AEs, AEs with severity Grade ≥ 3, AEs resulting in study discontinuation, and AEs resulting in death.

    Time frame: From Day 1 through Study Completion.

  2. Safety Endpoint: Proportion of participants experiencing SAEs leading to hospitalization.

    Time frame: From Day 1 through Study Completion.

  3. Safety Endpoint: Overall survival.

    Time frame: From Day 1 through Study Completion.

Study contacts

Contact information is provided by the study sponsor or research team.

Encoded Patient Advocacy

CONTACT

[email protected]

+1 (650) 398-4301

Sponsors and collaborators

Lead sponsor

Encoded Therapeutics

Industry

Registry information

Official study title

ENDEAVOR: A Clinical Study to Evaluate the Safety and Efficacy of ETX101, an AAV9-Delivered Gene Therapy in Infants and Children With SCN1A-Positive Dravet Syndrome

Acronym: ENDEAVOR

Important dates

Study start
2024
Primary completion
2028
Study completion
2033
First posted
Jun 15, 2022
Registry last updated
Jul 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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