A Phase 1/2 interventional study of ETX101 in Dravet Syndrome, sponsored by Encoded Therapeutics. Recruiting at 14 sites in 3 countries. Open to participants aged 6 Months to 17 Years. Per ClinicalTrials.gov, last updated 2026-10-23.
Sponsored by Encoded Therapeutics · Phase 1/2, Interventional, and Treatment
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.
92 studies on the registry are indexed under Epilepsies, Myoclonic; 21 are open to participants now.
This study's planned enrollment of 113 is above the median of 31 across 56 interventional studies indexed under Epilepsies, Myoclonic.
Browse Epilepsies, Myoclonic studies →Encoded Therapeutics is the lead sponsor of 4 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
The criteria were revised on the registry on Oct 23, 2026. See what changed
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Drug: ETX101
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.
Drug: 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.
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).
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.
Change from Baseline in Vineland-3 subdomain GSVs at Week 52.
Time frame: From Baseline to Week 52.
Change from Baseline in Bayley-4 subdomain GSVs at Week 52.
Time frame: From Baseline to Week 52.
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).
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).
Change from Baseline in the Vineland-3 Adaptive Behavior Composite standard score at Week 52.
Time frame: From Baseline to Week 52.
Change from Baseline in Vineland-3 subdomain raw scores at Week 52.
Time frame: From Baseline to Week 52.
Change from Baseline in Bayley-4 subdomain raw scores (excluding cognitive subdomain) at Week 52.
Time frame: From Baseline to Week 52.
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.
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.
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.
Safety Endpoint: Proportion of participants experiencing SAEs leading to hospitalization.
Time frame: From Day 1 through Study Completion.
Plan to share: No
No publications or documents are linked to this record.
Started May 2024 (actual). Primary completion is estimated for Jun 2028, 49 months after the start.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 23, 2026: primary completion Jan 2028 → Jun 2028 and completion Jan 2033 → Jun 2034.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: ETX101
Encoded Therapeutics