Dravet SyndromeLONG-DSNCT07251673
Longitudinal Study of Phenotypic and Developmental Severity in Patients With Dravet Syndrome With SCN1A Gene Mutation
An observational study of Dravet Syndrome, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
Trial summary
Dravet syndrome with SCN1A gene mutation is a developmental and epileptic encephalopathy characterized by treatment-resistant epilepsy and global developmental delay. Despite the considerable attention recently Dravet syndrome (DS) in drug development, studies characterising the progression of the neurodevelopmental… Read more about this study
- Who is it for?
- Ages 6 months to 21 years
- Conditions the study is for
- Dravet Syndrome
- How many people
- 50 participants
- Where
- 1 siteFrance
- Study dates
- 15 Sep 2025to 1 Oct 2030
- Phase
- Observational
- 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 months to 21 years
- All sexes
- No healthy volunteers
- Child, Adult
Study population: Patients aged 6 months to 21 years with Dravet syndrome due to a pathogenic or probably pathogenic variant of the SCN1A
Who may be able to join
- The patient or his/her legal representative must be able to give informed consent for participation in the study.
- The participant or legal representative are able (in the opinion of the investigator) to comply with the research protocol.
- Patient (male/female) between 6 months and 21 years of age inclusive at the time of consent.
- The patient has a confirmed pathogenic or probably pathogenic variant of the SCN1A gene demonstrated by a genetic test.
- The patient had normal development prior to the onset of the first seizure.
- The patient had an onset of epileptic seizures between the ages of 3 and 15 months inclusive.
- The patient is receiving at least one of the following anti-epileptic drugs prior to consent: brivaracetam, clobazam, cannabidiol, fenfluramine, levetiracetam, sodium valproate, stiripentol, topiramate
Who cannot join
- The patient has a copy number variation of the SCN1A gene affecting other genes, including a microdeletion of SCN1A.
- The patient has a mutation in the SCN1A gene on both alleles.
- The patient has a known or clinically suspected pathogenic mutation in a gene associated with epilepsy other than the SCN1A gene.
- The patient has a concomitant genetic mutation or clinical comorbidity deemed likely to disrupt the typical phenotype of Dravet syndrome.
- The patient has a known gain-of-function mutation, defined by functional studies, including p.Thr226Met.
- The patient has a history of neurodevelopmental abnormality prior to the onset of seizures, based on the medical record.
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- The patient has been seizure free for a period of one year prior to informed consent.
- The patient has, at any time, taken antiepileptic drugs with a worsening effect for 6 consecutive weeks or more, including: carbamazepine, eslicarbazepine, lacosamide, lamotrigine, oxcarbazepine, phenytoin (chronic oral administration), tiagabine and vigabatrin.
- The patient has already received innovative therapies such as antisense ologonucleotides, gene therapy or cell therapy.
- The patient has a structural abnormality on brain imaging (MRI or CT scan) which the principal investigator considers to be an epileptogenic lesion.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
France1 site, 1 recruiting
- Recruiting
Robert Debré Hospital
Paris, Ap-hp / DRCI, 75019
Stéphane AUVIN, MD, PhD, 0033140032000, stephane.auvin@aphp.fr
About this study
Dravet syndrome with SCN1A gene mutation is a developmental and epileptic encephalopathy characterized by treatment-resistant epilepsy and global developmental delay.
Despite the considerable attention recently Dravet syndrome (DS) in drug development, studies characterising the progression of the neurodevelopmental phenotype over time remain limited. In particular, many previous studies of natural history studies have been of short duration or have focused only on a subgroup of the paediatric population.
This prospective natural history study is being conducted to define more precisely the neurodevelopmental trajectory of SCN1A-positive Dravet syndrome in patients aged aged 6 months to 21 years with SCN1A mutations. The study will examine these characteristics over a 4-year period using standardised assessments. The study will also explore potential metabolomic biomarkers and their relationship with clinical outcomes.
Read the detailed description
A prospective cohort to document the evolutionary trajectory over a 4-year period of patients with Dravet syndrome with a confirmed pathogenic or probably pathogenic variant in the SCN1A gene aged between 6 months and 21 years.
Pre-selection/eligibility stage Patients and their legal representatives will be contacted by an investigator. Inclusion and non-inclusion criteria will be assessed to confirm the participant's eligibility, allowing entry into the study and completion of the baseline assessment. Following a discussion of the objectives, risks and benefits of the study, the patient's non-objection to taking part in the research will be obtained, together with the patient's assent, if applicable.
Baseline assessment (Year 0)
An initial visit will be organized to collect demographic, historical and clinical data, and to carry out :
- A detailed medical assessment (age, sex, history of seizures genetic diagnosis, co-morbidities, current treatments).
- The Vineland-3 (parental module), analyzed by a psychologist
- GMFM-66 for motor functions (by a physiotherapist).
- CGI-S scale (clinician and carer)
- An additional tube of blood taken during a blood test for metabolomics analysis (including serum GABA).
- Bayley-IV (up to 8 years, depending on chronological or developmental age).
Annual visits (Years 1 to 4)
Annual assessments will be carried out to document clinical progress and will include:
- A medical update (new diagnoses, types and frequency of seizures, treatments).
- The same assessment tools as at the initial visit (Vineland-3, GMFM-66, CGI-S, Bayley-IV).
- The CGI-I scale to measure changes since the previous visit.
- An extra tube of blood taken during a blood test for metabolomics for metabolomic analysis.
- The collection of data from medical examinations carried out as part of the treatment.
End of the study After four annual visits following the baseline assessment, the participant will complete the study. A final report will be drawn up to document the clinical and functional evolution of Dravet syndrome over a 4-year period
- Conditions
- Dravet Syndrome
- Keywords
- Dravet syndrom, epilepsy
- Medical subject headings
- Epilepsies, Myoclonic, Epilepsy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Dravet syndrom Cohort | Blood sample for metabolomic analysis and scale |
What is being measured
The primary outcome is the main question the study is designed to answer.
Score of scale Vineland-3
Change in adaptive function measured by the Vineland-3 over time at 1, 2, 3 and 4 years follow-up (160 is the maximum score and 20 is the minimum score - the higher score is the better outcome)
Measured: Up to 4 years
Secondary outcomes (5)
Score of scale Gross Motor Function Measure-66 (GMFM-66)
Changes in motor function and activity measured by the GMFM-66 Max value:201 Min value:0 Higher score is the better outcome
Measured: Up to 4 years
Score of scale Bayley-IV sub-domains
To study the evolution of adaptive capacities over time in Dravet syndrome by changes in raw score for Bayley-IV sub-domains (160 is the maximum score and higher score and 40 is the minimum score - the higher score is the better outcome)
Measured: Up to 4 years
Average Clinical Global Impressions (CGI) scale score at each age
To understand the severity of Dravet syndrome with SCN1A mutation (Rating by the investigator, where 1 is the best outcome and 7 is the worst outcome)
Measured: Up to 4 years
Score of improvement scale
To understand the severity of Dravet syndrome with SCN1A mutation and how this severity changes with age. (Rating by the investigator, where 1 is the best outcome and 7 is the worst outcome)
Measured: Up to 4 years
Dosage of serum GABA
Average serum GABA level in each age group
Measured: Up to 4 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Nov 2025
- Study start15 Sep 2025
- Primary completion1 Oct 2030 (estimated)
- Study completion1 Oct 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.
- More trials run by Assistance Publique - Hôpitaux de ParisThe sponsor's other registered studies.
- 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Assistance Publique - Hôpitaux de Paris
- Sponsor type
- University, hospital or other
- Collaborators
- Encoded Therapeutics
- Responsible party
- Sponsor
- Investigators
- Stéphane Auvin, MD, PhD, Principal investigator, Assistance Publique - Hôpitaux de Paris
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07251673
- Sponsor's protocol ID
- APHP241685
- Other IDs
- 2024-A02640-47
- Acronym
- LONG-DS
- Status last verified
- Feb 2026
- First submitted
- 19 Aug 2025
- Last updated
- 3 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Longitudinal Study of Phenotypic and Developmental Severity in Patients With Dravet Syndrome With SCN1A Gene Mutation
- ClinicalTrials.gov ID
- NCT07251673
- Acronym / sponsor ID
- LONG-DS / APHP241685
- Conditions
- Dravet Syndrome
- Keywords
- Dravet syndrom, epilepsy
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Assistance Publique - Hôpitaux de ParisUniversity, hospital or other
- Collaborators
- Encoded Therapeutics
- Study start
- 15 Sep 2025 (actual)
- Primary completion
- 1 Oct 2030 (estimated)
- Study completion
- 1 Oct 2030 (estimated)
- First posted
- 26 Nov 2025 (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.
Dravet syndrome with SCN1A gene mutation is a developmental and epileptic encephalopathy characterized by treatment-resistant epilepsy and global developmental delay.
Despite the considerable attention recently Dravet syndrome (DS) in drug development, studies characterising the progression of the neurodevelopmental phenotype over time remain limited. In particular, many previous studies of natural history studies have been of short duration or have focused only on a subgroup of the paediatric population.
This prospective natural history study is being conducted to define more precisely the neurodevelopmental trajectory of SCN1A-positive Dravet syndrome in patients aged aged 6 months to 21 years with SCN1A mutations. The study will examine these characteristics over a 4-year period using standardised assessments. The study will also explore potential metabolomic biomarkers and their relationship with clinical outcomes.
Detailed description
A prospective cohort to document the evolutionary trajectory over a 4-year period of patients with Dravet syndrome with a confirmed pathogenic or probably pathogenic variant in the SCN1A gene aged between 6 months and 21 years.
Pre-selection/eligibility stage Patients and their legal representatives will be contacted by an investigator. Inclusion and non-inclusion criteria will be assessed to confirm the participant's eligibility, allowing entry into the study and completion of the baseline assessment. Following a discussion of the objectives, risks and benefits of the study, the patient's non-objection to taking part in the research will be obtained, together with the patient's assent, if applicable.
Baseline assessment (Year 0)
An initial visit will be organized to collect demographic, historical and clinical data, and to carry out :
- A detailed medical assessment (age, sex, history of seizures genetic diagnosis, co-morbidities, current treatments).
- The Vineland-3 (parental module), analyzed by a psychologist
- GMFM-66 for motor functions (by a physiotherapist).
- CGI-S scale (clinician and carer)
- An additional tube of blood taken during a blood test for metabolomics analysis (including serum GABA).
- Bayley-IV (up to 8 years, depending on chronological or developmental age).
Annual visits (Years 1 to 4)
Annual assessments will be carried out to document clinical progress and will include:
- A medical update (new diagnoses, types and frequency of seizures, treatments).
- The same assessment tools as at the initial visit (Vineland-3, GMFM-66, CGI-S, Bayley-IV).
- The CGI-I scale to measure changes since the previous visit.
- An extra tube of blood taken during a blood test for metabolomics for metabolomic analysis.
- The collection of data from medical examinations carried out as part of the treatment.
End of the study After four annual visits following the baseline assessment, the participant will complete the study. A final report will be drawn up to document the clinical and functional evolution of Dravet syndrome over a 4-year period
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Dravet syndrom Cohort | – | –Blood sample for metabolomic analysis and scale |
Who may qualify
- Ages
- 6 months to 21 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
- Study population
- Patients aged 6 months to 21 years with Dravet syndrome due to a pathogenic or probably pathogenic variant of the SCN1A
Key inclusion criteria (7 listed)
- The patient or his/her legal representative must be able to give informed consent for participation in the study.
- The participant or legal representative are able (in the opinion of the investigator) to comply with the research protocol.
- Patient (male/female) between 6 months and 21 years of age inclusive at the time of consent.
- The patient has a confirmed pathogenic or probably pathogenic variant of the SCN1A gene demonstrated by a genetic test.
- The patient had normal development prior to the onset of the first seizure.
Key exclusion criteria (10 listed)
- The patient has a copy number variation of the SCN1A gene affecting other genes, including a microdeletion of SCN1A.
- The patient has a mutation in the SCN1A gene on both alleles.
- The patient has a known or clinically suspected pathogenic mutation in a gene associated with epilepsy other than the SCN1A gene.
- The patient has a concomitant genetic mutation or clinical comorbidity deemed likely to disrupt the typical phenotype of Dravet syndrome.
- The patient has a known gain-of-function mutation, defined by functional studies, including p.Thr226Met.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Score of scale Vineland-3
Time frame: Up to 4 years
Change in adaptive function measured by the Vineland-3 over time at 1, 2, 3 and 4 years follow-up (160 is the maximum score and 20 is the minimum score - the higher score is the better outcome)
5 secondary outcomes
Score of scale Gross Motor Function Measure-66 (GMFM-66)
Time frame: Up to 4 years
Score of scale Bayley-IV sub-domains
Time frame: Up to 4 years
Average Clinical Global Impressions (CGI) scale score at each age
Time frame: Up to 4 years
Score of improvement scale
Time frame: Up to 4 years
Dosage of serum GABA
Time frame: Up to 4 years
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 3 Feb 2026.
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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.
Stéphane Auvin, MD, PhD principal investigator
Assistance Publique - Hôpitaux de Paris
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Dravet Syndrome, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
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 7 inclusion and 10 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: looking for participants now, as of the sponsor's last update on 3 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. 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.
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?
Contact Stéphane Auvin, MD, PhD (0033140032000, stephane.auvin@aphp.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Score of scale Vineland-3 (time frame: Up to 4 years). 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 3 Feb 2026.