Dravet SyndromePhase 1/2UK OnlyNCT06283212
A Clinical Study to Evaluate the Safety and Efficacy of ETX101, an AAV9-Delivered Gene Therapy in Children With SCN1A-positive Dravet Syndrome
A Phase 1/2 study testing ETX101 in people with Dravet Syndrome, run by Encoded Therapeutics at 3 sites in United Kingdom.
Trial summary
EXPEDITION is a Phase 1/2 study in the UK to evaluate the safety and efficacy of ETX101 in participants with SCN1A-positive Dravet Syndrome aged 6 to < 48 months. The study follows and open-label, dose-escalation design. Read more about this study
- Who is it for?
- Ages 6 to 47 months
- Conditions the study is for
- Dravet Syndrome
- What is being tested?
- ETX101
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 5 participants
- Where
- 3 sitesUnited Kingdom
- Study dates
- 9 May 2024to Oct 2030
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 6 to 47 months
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- Participant has a predicted loss of function pathogenic or likely pathogenic SCN1A variant
- Participant must have experienced their first seizure between the age of 3 and 15 months
- Participant must have a clinical diagnosis of Dravet syndrome or the treating clinician must have high clinical suspicion of a diagnosis of Dravet syndrome
- Participant is receiving at least one prophylactic antiseizure medication
Who cannot join
- 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 is currently taking or has taken antiseizure medications (ASMs) at a therapeutic dose that are contraindicated in Dravet syndrome, including sodium channel blockers.
- 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.
Trial locations and contacts
3 sites in 1 country.
United Kingdom3 sites
Queen Elizabeth Hospital
Glasgow, G51 4TF
Great Ormond Street Hospital
London, WC1N3JH
Sheffield Children's Hospital
Sheffield, S10 2TH
About this study
Official title: EXPEDITION: A Clinical Study to Evaluate the Safety and Efficacy of ETX101, an AAV9-Delivered Gene Therapy in Children With SCN1A-positive Dravet Syndrome
EXPEDITION is a Phase 1/2 study in the UK to evaluate the safety and efficacy of ETX101 in participants with SCN1A-positive Dravet Syndrome aged 6 to < 48 months. The study follows and open-label, dose-escalation design.
- Conditions
- Dravet Syndrome
- Being tested
- ETX101
- Medical subject headings
- Epilepsies, Myoclonic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ETX101Drug
ETX101 is composed of a non-replicating, recombinant adeno-associated viral serotype 9 (rAAV9) vector used to deliver a GABAergic regulatory element (reGABA) and an engineered transcription factor that increases transcription of the SCN1A gene (eTFSCN1A)
| Study group | Role | What they receive |
|---|---|---|
| Cohort A | Experimental | Cohort A will evaluate ETX101 dose level 1. Receives: Drug: ETX101 |
| Cohort B | Experimental | Cohort B will evaluate ETX101 dose level 2. Receives: Drug: ETX101 |
| Cohort C | Experimental | Cohort C will evaluate ETX101 dose level 3. Receives: Drug: ETX101 |
| Cohort D | Experimental | Cohort D will evaluate ETX101 dose level 4. Receives: Drug: ETX101 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percent change in monthly countable seizure frequency (MCSF) between the Pre-Dosing Seizure Period and the Post-Dosing Assessment Period.
Measured: Between the Pre-Dosing Seizure Period and the Post-Dosing Assessment Period (defined as Week 5 to Week 52)
Secondary outcomes (10)
Change from Baseline in Bayley-4 cognitive subdomain raw score at Week 52
Measured: Baseline to Week 52
Change from Baseline in Vineland-3 subdomain GSVs at Week 52.
Measured: Baseline to Week 52.
Change from Baseline in Bayley-4 subdomain GSVs at Week 52.
Measured: Baseline to Week 52.
Proportion of participants achieving ≥ 75% reduction in MCSF between the Pre-Dosing Seizure Period and the Post-Dosing Assessment Period.
Measured: 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.
Measured: 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.
Measured: Baseline to Week 52.
Change from Baseline in Vineland-3 subdomain raw scores at Week 52.
Measured: Baseline to Week 52.
Change from Baseline in Bayley-4 subdomain raw scores (excluding cognitive subdomain) at Week 52.
Measured: 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.
Measured: 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.
Measured: Baseline to Week 52.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Feb 2024
- Study start9 May 2024
- Primary completionOct 2030 (estimated)
- Study completionOct 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Dravet SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 5 participants (actual)
Sponsor and investigators
- Lead sponsor
- Encoded Therapeutics
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Salvador Rico, M.D., Ph. D, Study director, Encoded Therapeutics
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06283212
- Sponsor's protocol ID
- ETX-DS-005
- Acronym
- UK Only
- Status last verified
- Jun 2026
- First submitted
- 22 Feb 2024
- Last updated
- 8 Jun 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 8 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- EXPEDITION: A Clinical Study to Evaluate the Safety and Efficacy of ETX101, an AAV9-Delivered Gene Therapy in Children With SCN1A-positive Dravet Syndrome
- ClinicalTrials.gov ID
- NCT06283212
- Acronym / sponsor ID
- UK Only / ETX-DS-005
- Conditions
- Dravet Syndrome
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 5 participants (actual)
- Lead sponsor
- Encoded TherapeuticsIndustry (pharma, biotech, devices)
- Study start
- 9 May 2024 (actual)
- Primary completion
- Oct 2030 (estimated)
- Study completion
- Oct 2030 (estimated)
- First posted
- 28 Feb 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
EXPEDITION is a Phase 1/2 study in the UK to evaluate the safety and efficacy of ETX101 in participants with SCN1A-positive Dravet Syndrome aged 6 to < 48 months. The study follows and open-label, dose-escalation design.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Cohort A | Experimental | Drug: ETX101Cohort A will evaluate ETX101 dose level 1. |
| Cohort B | Experimental | Drug: ETX101Cohort B will evaluate ETX101 dose level 2. |
| Cohort C | Experimental | Drug: ETX101Cohort C will evaluate ETX101 dose level 3. |
| Cohort D | Experimental | Drug: ETX101Cohort D will evaluate ETX101 dose level 4. |
Who may qualify
- Ages
- 6 to 47 months
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (4 listed)
- Participant has a predicted loss of function pathogenic or likely pathogenic SCN1A variant
- Participant must have experienced their first seizure between the age of 3 and 15 months
- Participant must have a clinical diagnosis of Dravet syndrome or the treating clinician must have high clinical suspicion of a diagnosis of Dravet syndrome
- Participant is receiving at least one prophylactic antiseizure medication
Key exclusion criteria (8 listed)
- 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 is currently taking or has taken antiseizure medications (ASMs) at a therapeutic dose that are contraindicated in Dravet syndrome, including sodium channel blockers.
- Participant has experienced seizure freedom for a period of 4 consecutive weeks within the 90-day period prior to informed consent.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ETX101ETX101 is composed of a non-replicating, recombinant adeno-associated viral serotype 9 (rAAV9) vector used to deliver a GABAergic regulatory element (reGABA) and an engineered transcription factor that increases transcription of the SCN1A gene (eTFSCN1A) | Drug | Cohort A, Cohort B, Cohort C, Cohort D |
Primary outcome
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)
10 secondary outcomes
Change from Baseline in Bayley-4 cognitive subdomain raw score at Week 52
Time frame: Baseline to Week 52
Change from Baseline in Vineland-3 subdomain GSVs at Week 52.
Time frame: Baseline to Week 52.
Change from Baseline in Bayley-4 subdomain GSVs at Week 52.
Time frame: 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: Baseline to Week 52.
Change from Baseline in Vineland-3 subdomain raw scores at Week 52.
Time frame: Baseline to Week 52.
Change from Baseline in Bayley-4 subdomain raw scores (excluding cognitive subdomain) at Week 52.
Time frame: 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: 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: Baseline to Week 52.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Jun 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Salvador Rico, M.D., Ph. D study director
Encoded Therapeutics
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing ETX101 in people with Dravet Syndrome, run by Encoded Therapeutics at 3 sites in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 8 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the 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)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Jun 2026.