A Study of Soticlestat as an Add-on Therapy in Children and Young Adults With Dravet Syndrome
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ClinicalTrials.gov Identifier: NCT04940624 |
Recruitment Status :
Recruiting
First Posted : June 25, 2021
Last Update Posted : June 21, 2022
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The main aim of the study is to learn if soticlestat, when given as an add-on therapy, reduces the number of convulsive seizures in children and young adults with Dravet Syndrome.
Participants will receive their standard anti-seizure therapy, plus either a tablet of soticlestat or placebo for 16 weeks. A placebo looks just like soticlestat but will not have any medicine in it.
Participants may continue treatment in an extension study, based on the extension study's entry criteria. Those that want to stop treatment will have a gradual dose reduction during 1 week and then be followed up for 2 weeks.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Dravet Syndrome (DS) | Drug: Soticlestat Drug: Placebo | Phase 3 |
The drug being tested in this study is called soticlestat (TAK-935). Soticlestat as an adjunctive therapy will be assessed for efficacy, safety, and tolerability in pediatric and adult participants with Dravet Syndrome (DS).
The study will enroll approximately 142 pediatric and young adult patients. Participants will be randomized at a 1:1 ratio to receive standard of care (SOC) plus one of the following adjunctive therapies:
- Soticlestat or
- Placebo
The total daily dose of study drug will be calculated based on body weight in the 4 weeks Titration Period. Following the Titration Period, participants will continue to receive the same dose in the Maintenance Period. The dose will then be down-tapered.
This multi-center trial will be conducted worldwide. The overall time to participate in the study will be from 22-25 weeks. Participants may have an option to either enter or to discontinue Open-label Extension (OLE). If participants discontinue, they will be followed-up for safety.
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 142 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel Group Study to Evaluate the Efficacy, Safety, and Tolerability of Soticlestat as Adjunctive Therapy in Pediatric and Young Adult Subjects With Dravet Syndrome (DS) |
Actual Study Start Date : | October 28, 2021 |
Estimated Primary Completion Date : | March 5, 2023 |
Estimated Study Completion Date : | March 5, 2023 |

Arm | Intervention/treatment |
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Experimental: Soticlestat
Participants weighing <45 kg: Soticlestat, mini-tablets, at the dose of 40 mg to 200 mg, orally or via gastrostomy tube (G-tube) or percutaneous endoscopic gastrostomy (PEG) tube, twice daily (BID) based on the body weight up to 4 weeks in Titration Period. Participants will continue to receive the dose that they are on at the end of the Titration Period, for 12 weeks in the Maintenance Period. The total duration of the treatment will be up to 16 weeks (Treatment Period). The dose will be tapered down if participants decide to discontinue the treatment. Participants weighing ≥45 kg: Soticlestat mini-tablets or tablets with a starting dose of 100 mg BID followed by 200 mg BID and, then 300 mg BID, up to 4 weeks in Titration Period. Participants will continue to receive 300 mg BID for 12 weeks in the Maintenance Period. The total duration of the treatment will be up to 16 weeks (Treatment Period). The dose will be tapered down if participants decide to discontinue the treatment. |
Drug: Soticlestat
Soticlestat mini-tablets or tablets.
Other Name: TAK-935 |
Placebo Comparator: Placebo
Soticlestat placebo-matching mini-tablets or tablets, orally or via G-tube or PEG tube, BID, up to 4 weeks in the Titration Period. Participants will continue to receive the soticlestat placebo-matching mini-tablets or tablets for 12 weeks in the Maintenance Period. The total duration of the treatment will be up to 16 weeks. Soticlestat matching tapering will be done to maintain the blind if participants decide to discontinue the treatment.
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Drug: Placebo
Soticlestat placebo-matching mini-tablets or tablets. |
- Percent Change From Baseline in Convulsive Seizure Frequency per 28 days During the Full Treatment Period [ Time Frame: Baseline up to Week 16 ]Convulsive seizure frequency per 28 days is defined as total number of convulsive seizures reported during the period divided by number of days during the period seizures were assessed multiplied by 28. Percent change from Baseline will be defined as (frequency of seizures per 28 days during Treatment Period - frequency of seizures per 28 days at Baseline) divided by the frequency of seizures per 28 days at Baseline multiplied by 100.
- Percent Change From Baseline in Convulsive Seizure Frequency per 28 days During the Maintenance Period (EMA Region Specific) [ Time Frame: Baseline up to Week 16 ]Convulsive seizure frequency per 28 days is defined as total number of convulsive seizures reported during the period divided by number of days during the period seizures were assessed multiplied by 28. Percent change from Baseline will be defined as (frequency of seizures per 28 days during Maintenance Period - frequency of seizures per 28 days at Baseline) divided by the frequency of seizures per 28 days at Baseline multiplied by 100. This outcome measure is European Medicines Agency (EMA) specific.
- Percentage of Responders During Maintenance Period [ Time Frame: Baseline up to Week 16 ]Responders are defined as those with ≥50% reduction from baseline in convulsive seizures during the Maintenance Period.
- Percentage of Responders During the Full Treatment Period [ Time Frame: Baseline up to Week 16 ]Responders are defined as those with ≥50% reduction from baseline in convulsive seizures during the Treatment Period.
- Percent Change From Baseline in Frequency of all Seizures per 28 Days During the Maintenance Period [ Time Frame: Baseline up to Week 16 ]Seizure frequency per 28 days is defined as total number of seizures reported during the period divided by number of days during the period seizures were assessed multiplied by 28. Percent change from Baseline is defined as (frequency of seizures per 28 days during Maintenance Period - frequency of seizures per 28 days at Baseline) divided by the frequency of seizures per 28 days at Baseline multiplied by 100.
- Percent Change From Baseline in Frequency of all Seizures per 28 Days During the Full Treatment Period [ Time Frame: Baseline up to Week 16 ]Seizure frequency per 28 days is defined as total number of seizures reported during the period divided by number of days during the period seizures were assessed multiplied by 28. Percent change from Baseline is defined as (frequency of seizures per 28 days during Treatment Period - frequency of seizures per 28 days at Baseline) divided by the frequency of seizures per 28 days at Baseline multiplied by 100.
- Percent Change From Baseline in Convulsive Seizure Frequency per 28 days During the Maintenance Period [ Time Frame: Baseline up to Week 16 ]Convulsive seizure frequency per 28 days is defined as total number of convulsive seizures reported during the period divided by number of days during the period seizures were assessed multiplied by 28. Percent change from Baseline is defined as (frequency of seizures per 28 days during Maintenance Period - frequency of seizures per 28 days at Baseline) divided by frequency of seizures per 28 days at Baseline multiplied by 100.
- Percentage of Participants with ≤0%, >0% to ≤25%, >25% to ≤50%, >50% to ≤75%, and >75% to ≤100% Reduction in Convulsive Seizures in a Cumulative Response Curve [ Time Frame: Baseline up to Week 16 ]
- Change from Baseline in Percentage of Convulsive Seizure-free Days [ Time Frame: Baseline up to Week 16 ]Convulsive seizure-free days will be defined as number of days a participant remained convulsive seizure free after initiation of the treatment.
- Longest Convulsive Seizure-free Interval. [ Time Frame: Baseline up to Week 16 ]Longest convulsive seizure-free interval will be defined as the longest time period that the participant remained convulsive seizure free after initiation of the treatment.
- Number of Days When Rescue Antiseizure Medication (ASM) is Used [ Time Frame: Baseline up to Week 16 ]
- Clinical Global Impression of Improvement (CGI-I) Score [ Time Frame: Baseline up to Week 16 ]The CGI-I Clinician is a 7-point Likert scale that the investigator uses to rate a participant's change (improvement) in overall seizure control, behavior, safety and tolerability, after the initiation of study drug relative to Baseline (before treatment with study drug). The participant will be rated as follows: 1 (very much improved), 2 (much improved), 3 (minimally improved), 4 (no change), 5 (minimally worse), 6 (much worse), and 7 (very much worse). Higher score will indicate worse symptoms.
- Caregiver Global Impression of Improvement (Care GI-I) Score [ Time Frame: Baseline up to Week 16 ]The Care GI-I is a 7-point Likert scale that the caregiver uses to rate improvement in overall seizure control, behavior, safety and tolerability after the initiation of study drug relative to Baseline (before treatment with study drug). The participant will be rated as follows: 1 (very much improved), 2 (much improved), 3 (minimally improved), 4 (no change), 5 (minimally worse), 6 (much worse), and 7 (very much worse). The parent/caregiver will complete the Care GI-I via interview. Higher score will indicate worse symptoms.
- CGI-I Seizure Intensity and Duration Score [ Time Frame: Baseline up to Week 16 ]The CGI-I seizure Intensity and duration instrument is used by the parent/caregiver to rate improvement in intensity and duration of convulsive seizures from the first assessment. The participant's symptoms will be rated on 7-point scale as follows: 1 (very much improved), 2 (much improved), 3 (minimally improved), 4 (no change), 5 (minimally worse), 6 (much worse), and 7 (very much worse). Higher score will indicate worse symptoms.
- CGI-I Nonseizure Symptoms Score [ Time Frame: Baseline up to Week 16 ]The CGI-I nonseizure symptoms instrument is a series of single-item assessments that the investigator uses to rate improvement in the symptoms and impacts in select nonseizure domains since initiating the study drug. The participant will be rated on 7-point scale by the investigator as follows: 1 (very much improved), 2 (much improved), 3 (minimally improved), 4 (no change), 5 (minimally worse), 6 (much worse), and 7 (very much worse). At baseline, a symptoms form is completed by the clinician in collaboration with the primary caregiver to assess the participants status based on the presence of any nonseizure symptoms. Higher score will indicate worse symptoms.
- Change in Quality of Life Inventory-Disability (QI-Disability) Score [ Time Frame: Baseline up to Week 16 ]The QI-Disability tool is a parent/caregiver-reported questionnaire that evaluates quality of life in children with intellectual disabilities. It contains 32 items covering 6 domains of quality of life: physical health, positive emotions, negative emotions, social interaction, leisure and the outdoors, and independence. Scores are from a 5-point Likert scale and then are transformed to a scale of 0 to 100. Possible scores range from 0-100, with higher scores indicating better quality of life.

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Ages Eligible for Study: | 2 Years to 21 Years (Child, Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Has documented clinical diagnosis of Dravet Syndrome (DS).
- Has ≥4 convulsive seizures in each 1-month period in the 3 months before screening based on the historical information and has ≥4 convulsive seizures per 28 days during the 4- to 6-week prospective baseline period.
- Weighs ≥10 kg at the screening visit (Visit 1).
- Failure to control seizures despite appropriate trials of at least 2 ASMs based on historical information and is currently on an antiseizure therapy or other treatment options considered as SOC.
- Currently taking 0 to 4 antiseizure medication (ASMs) at stable doses for at least 4 weeks before the screening visit (Visit 1); benzodiazepines used chronically (daily) to treat seizures are considered ASMs. ASM dosing regimen must remain constant throughout the study.
Exclusion Criteria:
1. Unstable, clinically significant neurologic (other than the disease being studied), psychiatric, cardiovascular, ophthalmologic, pulmonary, hepatic, renal, metabolic, gastrointestinal, urologic, immunologic, hematopoietic, endocrine disease, malignancy including progressive tumors, or other abnormality that may impact the ability to participate in the study or that may potentially confound the study results. It is the responsibility of the investigator to assess the clinical significance; however, consultation with the medical monitor may be warranted.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04940624
Contact: Takeda Contact | +1-877-825-3327 | medinfoUS@takeda.com |

Study Director: | Study Director | Takeda |
Responsible Party: | Takeda |
ClinicalTrials.gov Identifier: | NCT04940624 |
Other Study ID Numbers: |
TAK-935-3001 jRCT2051210074 ( Registry Identifier: jRCT ) |
First Posted: | June 25, 2021 Key Record Dates |
Last Update Posted: | June 21, 2022 |
Last Verified: | June 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement. |
Supporting Materials: |
Study Protocol Statistical Analysis Plan (SAP) Informed Consent Form (ICF) Clinical Study Report (CSR) |
Access Criteria: | IPD from eligible studies will be shared with qualified researchers according to the criteria and process described on https://vivli.org/ourmember/takeda/. For approved requests, the researchers will be provided access to anonymized data (to respect patient privacy in line with applicable laws and regulations) and with information necessary to address the research objectives under the terms of a data sharing agreement. |
URL: | https://vivli.org/ourmember/takeda/ |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Product Manufactured in and Exported from the U.S.: | Yes |
Drug Therapy |
Epilepsies, Myoclonic Syndrome Disease Pathologic Processes Epilepsy, Generalized |
Epilepsy Brain Diseases Central Nervous System Diseases Nervous System Diseases Epileptic Syndromes |