ClinicalTrials.gov record NCT05419492

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

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Jul 27, 2026

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

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.
Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.
PhasePhase 1/2A study that combines safety and dose-finding (phase 1) with a first look at whether the treatment has an effect (phase 2).
Age6 months old to 17 years old
SexAll
LocationAustralia, United Kingdom, United States
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This Phase 1/2 study evaluates ETX101, a one-time AAV9-delivered gene therapy, in children with SCN1A-positive Dravet syndrome. The study has two parts: open-label dose exploration in younger infants and an open-label arm in older children, plus a randomized, double-blind, sham delayed-treatment control component. Main results are measured through Week 52 and include seizure counts and developmental assessments.

What it is studying. The study is testing the safety and efficacy of ETX101, a one-time intracerebroventricular (ICV) AAV9-delivered gene therapy designed to increase SCN1A gene transcription. It compares ETX101 with a sham delayed-treatment procedure in the randomized part and collects measures of seizure frequency and developmental functioning over the first year after treatment.

What the researchers hope to learn. To evaluate the safety of ETX101 and to measure its effects on monthly seizure frequency. To assess effects on developmental outcomes using standardized tests (for example, Bayley-4 and Vineland-3) and clinical global impression measures. To gather data that could inform dosing and design of future studies.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

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.

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Drug
  • ETX101

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

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 description and what participation involves

The registry record has no detailed description beyond the summary above.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

After screening, participants may have a one-time intracerebroventricular (ICV) administration of ETX101; in Part 2 participants are randomized (2:1) to ETX101 or a sham delayed‑treatment procedure and are blinded through Week 52. Follow-up visits occur through at least Week 52 and include seizure monitoring (for example, recording seizure frequency), developmental assessments such as Bayley‑4 and Vineland‑3, and safety monitoring (physical exams and tests). Part 1A is open-label dose escalation and Part 1B is open-label; Part 2 is double-blind with delayed treatment for the sham group. The registry record does not list exact visit schedules or all specific tests.

How the study is structured. Phase 1/2 interventional study with two parts. Part 1A is open-label, rule-based dose-escalation in younger participants; Part 1B is open-label at a single dose level in older children. Part 2 is randomized (2:1), double-blind (masked), sham delayed-treatment control through Week 52 and evaluates a single dose level. ETX101 is given as a one-time intracerebroventricular administration; outcomes include seizure counts and developmental tests up to Week 52.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

  • This is an early-phase study, mainly about safety and dose. What is already known about this treatment?
  • The listed sites are in Australia, United Kingdom, United States. Is any of them reachable for me, and does the study help with travel?
  • Which of the eligibility criteria would need to be checked with tests before I could join?

More on Dravet syndrome

This trial is also listed on this site under CDKL5 deficiency disorder.

Clinical trials22 trials listed for Dravet syndromeEvery trial the registry lists for Dravet syndrome, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in Dravet syndrome researchLatest monthly update: September 2026. Includes: CBD in practice. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start
May 14, 2024
Primary completion
January 2028 (estimated)
Study completion
January 2033 (estimated)
Target enrollment
47 participants (estimated)
Last updated on registry
Sep 22, 2026
Data verified
Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor
Encoded Therapeutics

Central study contact

If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.

Participating sites (14)

Terms used on this page · explanations by MedicalUpdates.ai

open-label
No masking is used, so the assigned intervention is not deliberately hidden from participants or study staff.
dose-escalation
Groups of participants receive increasing doses of a treatment, one group after another, to find a dose that can be given safely.
randomized
Participants are assigned to the study groups by chance, like a coin toss, rather than chosen by the doctor or the participant. This is done so the groups are comparable.
double-blind
Two types of people involved in the study do not know which intervention a participant is receiving. The ClinicalTrials.gov record specifies who is masked, for example participants, care providers, investigators or outcome assessors.
sham
A procedure designed to resemble the real procedure, for example the same visit and equipment, without its active part. It is the procedure equivalent of a placebo.
MRI
A scan that uses magnets and radio waves, not X-rays, to make detailed pictures of the inside of the body. Some implants and metal objects mean a person cannot have one.
CT scan
An X-ray scan that builds detailed cross-section images of the body. 'High-resolution' CT (HRCT) is used to look closely at the lungs.
informed consent
The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
investigational
A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
Inclusion Criteria
The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Exclusion Criteria
The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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