A Study of Soticlestat as an Add-on Therapy in Children and Young Adults With Dravet Syndrome

Takeda144 enrolled

Overview

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 DS. Participants will receive their standard antiseizure 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.

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 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 12-weeks Maintenance Period. This multi-center trial will be conducted worldwide. The overall time to participate in the study will be from 22-25 weeks. At the end of the Full Treatment Period, participants have the option to either complete the study and taper off the investigational product or to enter the OLE if they meet eligibility requirements. If participants discontinue, they will be followed-up on phone call approximately 14 days after the last dose of study drug for safety.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Enrollment

144

Conditions

Dravet Syndrome (DS)

Interventions

SoticlestatDRUG

Soticlestat mini-tablets or tablets.

PlaceboDRUG

Soticlestat placebo-matching mini-tablets or tablets.

Eligibility

Sex: ALLMin age: 2 YearsMax age: 21 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Has documented clinical diagnosis of DS. 2. Had ≥12 convulsive seizures over 12 weeks before screening based on the historical information and has had ≥4 convulsive seizures per 28 days during the 4- to 6-week prospective baseline period. 3. Weighs ≥10 kg at the screening visit (Visit 1). 4. Failure to control seizures despite appropriate trials of at least 1 ASM based on historical information and is currently on an antiseizure therapy or other treatment options considered as SOC. 5. Artisanal cannabidiols are allowed at a stable dose for at least 4 weeks before the screening visit (Visit 1); the dosing regimen and manufacturer should remain constant throughout the study (Artisanal cannabidiols will not be counted as ASMs.). 6. Currently taking 0 to 4 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. Fenfluramine and cannabidiol (Epidiolex) are allowed where available and should be counted as an ASM. 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.

Locations (66)

Outcomes

Primary Outcomes

Percent Change From Baseline in Convulsive Seizure Frequency Per 28 Days During the Full Treatment Period

Convulsive seizure frequency per 28 days was defined as the total number of convulsive seizures reported during the period divided by the number of days during the period seizures were assessed multiplied by 28. Percent change from Baseline was defined as (frequency of seizures per 28 days during the Full Treatment Period - frequency of seizures per 28 days at Baseline) divided by the frequency of seizures per 28 days at Baseline multiplied by 100.

Time frame: Baseline; Full Treatment Period: Weeks 1 to 16

Percent Change From Baseline in Convulsive Seizure Frequency Per 28 Days During the Maintenance Period

Convulsive seizure frequency per 28 days was defined as the 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 was 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.

Time frame: Baseline; Maintenance Period: Weeks 5 to 16

Secondary Outcomes

Percentage of Responders During Maintenance Period

Responders were defined as those with ≥50% reduction from Baseline in convulsive seizures during the Maintenance Period. Percentages were rounded off to the nearest single decimal place.

Time frame: Maintenance Period: Weeks 5 to 16

Percentage of Responders During the Full Treatment Period

Responders were defined as those with ≥50% reduction from Baseline in convulsive seizures during the Full Treatment Period. Percentages were rounded off to the nearest single decimal place.

Time frame: Full Treatment Period: Weeks 1 to 16

Percentage of Participants With ≤0%, >0% to ≤25%, >25% to ≤50%, >50% to ≤75%, and >75% to ≤100% Reduction in Convulsive Seizures During the Full Treatment Period

Data from ClinicalTrials.gov

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Phoenix Childrens Hospital

Phoenix, Arizona, United States

David Geffen School of Medicine at UCLA

Los Angeles, California, United States

University of California Benioff Children's Hospital

San Francisco, California, United States

Clinical Integrative Research Center of Atlanta

Atlanta, Georgia, United States

University of Iowa Hospitals & Clinics - (CRS)

Iowa City, Iowa, United States

NYU Comprehensive Epilepsy Center

New York, New York, United States

University of Toledo

Toledo, Ohio, United States

Medical University of South Carolina

Charleston, South Carolina, United States

Seattle Children's Hospital

Seattle, Washington, United States

Multicare Health System - Mary Bridge Pediatrics

Tacoma, Washington, United States

...and 56 more locations

Percent reduction from Baseline (%) was defined as \[(Full Treatment Period Convulsive Seizure Frequency - Baseline Convulsive Seizure Frequency) divided by Baseline Convulsive Seizure Frequency\] multiplied by 100. Data was reported as reduction of ≤0%, \>0% to ≤25%, \>25% to ≤50%, \>50% to ≤75%, \>75% to ≤100% or more in seizures from Baseline. Percentages were rounded off to the nearest single decimal place.

Time frame: Full Treatment Period: Weeks 1 to 16

Percentage of Participants With Caregiver Global Impression of Improvement (Care GI-I) Scale Responses as Per the Parent/Caregiver Reported Impression at Week 16

The Care GI-I is a 7-point Likert scale that the caregiver used to rate improvement in overall seizure control, behavior, safety and tolerability after the initiation of study drug relative to Baseline (before treatment with the study drug). The participant was 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 completed the Care GI-I via interview. Lower scores indicate improvement. Percentages were rounded off to the nearest single decimal place.

Time frame: Week 16

Percentage of Participants With Clinical Global Impression of Improvement (CGI-I) Scale Responses as Per the Investigator Reported Impression at Week 16

The CGI-I (Clinician) is a 7-point Likert scale that the investigator used 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 the study drug). The participant was 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 investigator or designee completed the CGI-I. Lower scores indicate improvement. Percentages were rounded off to the nearest single decimal place.

Time frame: Week 16

Percentage of Participants With CGI-I Nonseizure Symptoms Instrument Responses for Each Domain as Per the Investigator Reported Impression at Week 16

The CGI-I non-seizure symptoms instrument is a series of single-item assessments that the investigator used to rate improvement in the symptoms and impacts in select non-seizure domains (alertness, communication, and disruptive behaviors) since initiating the study drug. The participant was rated by the investigator for each domain 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). Lower scores indicated improvement. Data for percentage of participants categorized based on the responses for each domain are presented. Percentages were rounded off to the nearest single decimal place.

Time frame: Week 16

Change From Baseline in Quality of Life Inventory-Disability (QI-Disability) Total Score at Week 16

The QI-Disability tool is a parent/caregiver-reported questionnaire that evaluated the 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. Each QI-Disability item is rated on a Likert scale of: Never, Rarely, Sometimes, Often, and Very Often. Items were linearly transformed to a scale of 0 to 100, with higher scores representing better quality of life. Domain scores are calculated by averaging item scores. The domain scores are summed and divided by 6 to yield a total score. The total score ranges from 0 to 100, with higher scores indicating a better quality of life. A negative change from Baseline implies deteriorating quality of life. Mixed-effects model for repeated measures (MMRM) was used for analysis.

Time frame: Baseline, Week 16

Percentage of Participants With CGI-I Seizure Intensity and Duration Instrument Responses as Per the Parent/Caregiver Reported Impression at Week 16

The CGI-I seizure intensity and duration instrument was used by the parent/caregiver to rate changes in intensity and/or duration of the most impactful seizures from the first assessment. The participant's symptoms were 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). Lower scores indicate improvement. Percentages were rounded off to the nearest single decimal place.

Time frame: Week 16

Percent Change From Baseline in Frequency of All Seizures Per 28 Days During the Maintenance Period

Seizure frequency per 28 days was defined as the total number of seizures reported during the period divided by the number of days during the period seizures were assessed multiplied by 28. Percent change from Baseline was defined as (frequency of seizures per 28 days during the Maintenance Period - frequency of seizures per 28 days at Baseline) divided by the frequency of seizures per 28 days at Baseline multiplied by 100.

Time frame: Baseline; Maintenance Period: Weeks 5 to 16

Percent Change From Baseline in Frequency of All Seizures Per 28 Days During the Full Treatment Period

Seizure frequency per 28 days was defined as the 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 was defined as (frequency of seizures per 28 days during the Full Treatment Period - frequency of seizures per 28 days at Baseline) divided by the frequency of seizures per 28 days at Baseline multiplied by 100.

Time frame: Baseline; Full Treatment Period: Weeks 1 to 16

Change From Baseline in Percentage of Convulsive Seizure-free Days During the Full Treatment Period

Convulsive seizure-free days was defined as number of days a participant remained convulsive seizure-free after initiation of the treatment. The change from baseline in percentage of convulsive seizure-free days, was defined as the percentage of seizure-free days during the Full Treatment Period minus the percentage of seizure-free days during the Baseline. A linear model with treatment group and age stratum as factors and baseline percentage as a covariate was used for analysis.

Time frame: Baseline up to Week 16

Longest Convulsive Seizure-free Interval During the Full Treatment Period

Longest convulsive seizure-free interval was defined as the longest time period that the participant remained convulsive seizure free after initiation of the treatment. A linear model with treatment group and age stratum as factors was used for analysis.

Time frame: Full Treatment Period: Weeks 1 to 16

Number of Days When Rescue Antiseizure Medication (ASM) is Used During the Full Treatment Period

Use of rescue ASM was recorded in the case report form (CRF) along with start and end date of medication. Based on the start and end dates for all rescue ASMs taken by a participant, the number of days during the Full Treatment Period when rescue ASM was used was derived.

Time frame: Full Treatment Period: Weeks 1 to 16