Dravet Syndrome (DS)Phase 3NCT06422377
A Study Evaluating Soticlestat in Participants With Dravet Syndrome or Lennox-Gastaut Syndrome Who Have Been Exposed to Fenfluramine
A Phase 3 study testing Soticlestat in people with Dravet Syndrome (DS) and Lennox-Gastaut Syndrome (LGS), run by Takeda at 1 site in Denmark.
Trial summary
The purpose of this study is to check how soticlestat impacts symptoms of Dravet syndrome [DS] and Lennox-Gastaut syndrome [LGS] in participants who have been exposed to fenfluramine. Read more about this study
- Who is it for?
- Ages 2 to 65 years
- Conditions the study is for
- Dravet Syndrome (DS), Lennox-Gastaut Syndrome (LGS)
- What is being tested?
- Soticlestat
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 1 participants
- Where
- 1 siteDenmark
- Study dates
- 25 Apr 2024to 14 Aug 2024
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 2 to 65 years
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- The participant has been exposed to fenfluramine (currently on or used previously).
- The participant has a clinical diagnosis of LGS and a history of, on average, ≥12 MMD seizures in the last 90 days immediately before screening based on historical information, and the participant has ≥4 MMD seizures during a minimum of 4 weeks of seizure data collection during the prospective baseline period.
- The participant is currently taking 0 to 5 antiseizure treatments (eg. antiseizure medications [ASMs], vagus nerve stimulation [VNS], ketogenic diet) at stable doses.
Who cannot join
- The participant is currently enrolled in a clinical study involving an investigational product or treatment device (ie, not approved in that country, other than soticlestat), or concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study. Note: Compatibility will be determined on the basis of consultation with the sponsor/designee.
- The participant has a known hypersensitivity to any component of the soticlestat formulation.
- Participants aged ≥6 years who have positive answers on item numbers 4 or 5 on the Columbia-Suicide Severity Rating Scale (C-SSRS) before dosing are excluded. This scale will only be administered to participants aged ≥6 years at the time of enrollment or participants who turn 6 after enrollment.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: An Open-label, Nonrandomized, Phase 3 Study to Evaluate the Efficacy and Safety of Soticlestat in Participants With Dravet Syndrome or Lennox-Gastaut Syndrome Who Have Been Exposed to Fenfluramine
The purpose of this study is to check how soticlestat impacts symptoms of Dravet syndrome [DS] and Lennox-Gastaut syndrome [LGS] in participants who have been exposed to fenfluramine.
Read the detailed description
The drug being tested in this study is called soticlestat. Soticlestat is being tested to treat people who have DS or LGS and have been exposed to fenfluramine. This study will assess the efficacy and safety of soticlestat in addition to standard care in the treatment of DS or LGS.
The study will enroll approximately 45 patients. This study comprises a screening period of up to 6 weeks, a 4-week titration period, a 48-week maintenance period, a taper period of up to 1 week and a follow-up safety visit. Participants will be enrolled to receive soticlestat along with the standard of care:
- Soticlestat 100-300 milligrams (mg)
Participants will receive oral administration of soticlestat Dose 1 (days 1 to 7), Dose 2 (days 8 to 14), and Dose 3 (Days 15 to 28) with a minimum dose of 100 mg to a maximum dose of 300 mg depending on participant's body weight in the titration period followed by maintenance period up to end of treatment (up to approximately 52 weeks). Percent change from baseline in convulsive in participants with DS and major motor drop (MMD) in participants with LGS seizure frequency per 28 days during the initial 12 weeks of the maintenance period will be assessed.
This multi-center trial will be conducted in the United Kingdom and Europe. The overall time to participate in this study is approximately 60 weeks. Participants will make multiple visits to the clinic and will be followed up for safety by visiting the clinic or by telephone approximately 2 weeks after the last dose of the study drug.
- Being tested
- Soticlestat
- Keywords
- Drug Therapy
- Medical subject headings
- Epilepsies, Myoclonic, Lennox Gastaut Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SoticlestatDrug
Also called TAK-935
Soticlestat tablets or mini-tablets
| Study group | Role | What they receive |
|---|---|---|
| Soticlestat | Experimental | Participant received soticlestat at a starting dose of 100 mg to 200 mg in the 4-week titration. As a part of maintenance (initially planned for 48 weeks per protocol), participant remained on the 200 mg BID dose for 9 days followed by a 1-week taper to receive soticlestat 100 mg BID. Receives: Drug: Soticlestat |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percent Change From Baseline in Convulsive Seizure Frequency Per 28 Days During First 12 Weeks of Maintenance Period for DS Participants
Measured: Baseline to Week 12 of Maintenance Period
Percent Change From Baseline in Major Motor Drop (MMD) Seizure Frequency Per 28 Days During First 12 Weeks of Maintenance Period for LGS Participants
Measured: Baseline to Week 12 of Maintenance Period
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 May 2024
- Study start25 Apr 2024
- Primary completion14 Aug 2024
- Study completion14 Aug 2024
Why it stopped: Business decision unrelated to patient safety.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Dravet Syndrome (DS)Studies of the same condition, open and under way.
- More trials run by TakedaThe 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
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 1 participants (actual)
Sponsor and investigators
- Lead sponsor
- Takeda
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Takeda (Note: This product was divested to Mistrau Bio, Inc. in 2026)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06422377
- Sponsor's protocol ID
- TAK-935-3004
- Other IDs
- 2023-504104-29-00, 2023
- Status last verified
- Aug 2026
- First submitted
- 15 May 2024
- Last updated
- 4 Sep 2026
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: De-identified individual participant data from this particular study will not be shared as there is a reasonable likelihood that individual patients could be re-identified (due to the limited number of study participants/study sites, …).
Study at a glance
From the registry record, last updated by the sponsor on 4 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-label, Nonrandomized, Phase 3 Study to Evaluate the Efficacy and Safety of Soticlestat in Participants With Dravet Syndrome or Lennox-Gastaut Syndrome Who Have Been Exposed to Fenfluramine
- ClinicalTrials.gov ID
- NCT06422377
- Acronym / sponsor ID
- TAK-935-3004
- Keywords
- Drug Therapy
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Business decision unrelated to patient safety.
- Enrolment
- 1 participants (actual)
- Lead sponsor
- TakedaIndustry (pharma, biotech, devices)
- Study start
- 25 Apr 2024 (actual)
- Primary completion
- 14 Aug 2024 (actual)
- Study completion
- 14 Aug 2024 (actual)
- First posted
- 21 May 2024 (actual)
- Results
- Posted 6 Mar 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to check how soticlestat impacts symptoms of Dravet syndrome [DS] and Lennox-Gastaut syndrome [LGS] in participants who have been exposed to fenfluramine.
Detailed description
The drug being tested in this study is called soticlestat. Soticlestat is being tested to treat people who have DS or LGS and have been exposed to fenfluramine. This study will assess the efficacy and safety of soticlestat in addition to standard care in the treatment of DS or LGS.
The study will enroll approximately 45 patients. This study comprises a screening period of up to 6 weeks, a 4-week titration period, a 48-week maintenance period, a taper period of up to 1 week and a follow-up safety visit. Participants will be enrolled to receive soticlestat along with the standard of care:
- Soticlestat 100-300 milligrams (mg)
Participants will receive oral administration of soticlestat Dose 1 (days 1 to 7), Dose 2 (days 8 to 14), and Dose 3 (Days 15 to 28) with a minimum dose of 100 mg to a maximum dose of 300 mg depending on participant's body weight in the titration period followed by maintenance period up to end of treatment (up to approximately 52 weeks). Percent change from baseline in convulsive in participants with DS and major motor drop (MMD) in participants with LGS seizure frequency per 28 days during the initial 12 weeks of the maintenance period will be assessed.
This multi-center trial will be conducted in the United Kingdom and Europe. The overall time to participate in this study is approximately 60 weeks. Participants will make multiple visits to the clinic and will be followed up for safety by visiting the clinic or by telephone approximately 2 weeks after the last dose of the study drug.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Soticlestat | Experimental | Drug: SoticlestatParticipant received soticlestat at a starting dose of 100 mg to 200 mg in the 4-week titration. As a part of maintenance (initially planned for 48 weeks per protocol), participant remained on the 200 mg BID dose for 9 days followed by a 1-week taper to receive soticlestat 100 mg BID. |
Who may qualify
- Ages
- 2 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (3 listed)
- The participant has been exposed to fenfluramine (currently on or used previously).
- The participant has a clinical diagnosis of LGS and a history of, on average, ≥12 MMD seizures in the last 90 days immediately before screening based on historical information, and the participant has ≥4 MMD seizures during a minimum of 4 weeks of seizure data collection during the prospective baseline period.
- The participant is currently taking 0 to 5 antiseizure treatments (eg. antiseizure medications [ASMs], vagus nerve stimulation [VNS], ketogenic diet) at stable doses.
Key exclusion criteria (3 listed)
- The participant is currently enrolled in a clinical study involving an investigational product or treatment device (ie, not approved in that country, other than soticlestat), or concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study. Note: Compatibility will be determined on the basis of consultation with the sponsor/designee.
- The participant has a known hypersensitivity to any component of the soticlestat formulation.
- Participants aged ≥6 years who have positive answers on item numbers 4 or 5 on the Columbia-Suicide Severity Rating Scale (C-SSRS) before dosing are excluded. This scale will only be administered to participants aged ≥6 years at the time of enrollment or participants who turn 6 after enrollment.
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 |
|---|---|---|
| SoticlestatAlso: TAK-935Soticlestat tablets or mini-tablets | Drug | Soticlestat |
Primary outcome
Percent Change From Baseline in Convulsive Seizure Frequency Per 28 Days During First 12 Weeks of Maintenance Period for DS Participants
Time frame: Baseline to Week 12 of Maintenance Period
Percent Change From Baseline in Major Motor Drop (MMD) Seizure Frequency Per 28 Days During First 12 Weeks of Maintenance Period for LGS Participants
Time frame: Baseline to Week 12 of Maintenance Period
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Sep 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- To obtain more information on the study, click this link.Link provided by the sponsor.
- Individual participant dataSharing planned: No. De-identified individual participant data from this particular study will not be shared as there is a reasonable likelihood that individual patients could be re-identified (due to the limited number of study participants/study sites, …).
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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.
Medical Director study director
Takeda (Note: This product was divested to Mistrau Bio, Inc. in 2026)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Soticlestat in people with Dravet Syndrome (DS) and Lennox-Gastaut Syndrome (LGS), run by Takeda at 1 site in Denmark.
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 3 inclusion and 3 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: stopped early, as of the sponsor's last update on 4 Sep 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 Denmark. 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 phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 6 Mar 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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 From Baseline in Convulsive Seizure Frequency Per 28 Days During First 12 Weeks of Maintenance Period for DS Participants (time frame: Baseline to Week 12 of Maintenance Period). The study lists 2 primary outcomes in all. 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 4 Sep 2026.