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

Takeda

Status and phase: Completed; Phase 3

Conditions: Dravet Syndrome (DS)

Treatments: Drug: Soticlestat; Drug: Placebo

Study type: Interventional

Funder types: Industry

Identifiers

NCT04940624

2021-002480-22 (EudraCT Number)

TAK-935-3001

jRCT2051210074 (Registry Identifier)

Details and patient eligibility

About

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.

Full description

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.

Enrollment: 144 patients

Sex: All

Ages: 2 to 21 years old

Volunteers: No Healthy Volunteers

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.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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144 participants in 2 patient groups, including a placebo group

Placebo

Placebo Comparator group

Description:

Soticlestat placebo-matching mini-tablets or tablets, orally or via gastrostomy tube (G-tube) or low-profile gastric tube (MIC-KEY) button or jejunostomy tube (J-tube), twice daily (BID), up to 4 weeks during titration. Participants continued to receive the soticlestat placebo-matching mini-tablets or tablets for 12 weeks during maintenance. The total duration of the treatment was up to 16 weeks (Full Treatment Period). Soticlestat matching tapering was done to maintain the blind if participants decided to discontinue the treatment.

Treatment:

Drug: Placebo

Soticlestat

Experimental group

Description:

Participants weighing \<45 kg: Soticlestat, mini-tablets, at the dose of 40 mg to 200 mg, orally or via G-tube or MIC-KEY button or J-tube, BID based on the body weight up to 4 weeks during titration. Participants continued to receive the dose that they were on at the end of the titration, for 12 weeks during maintenance. The total duration of the treatment was up to 16 weeks (Full Treatment Period) with dose tapered down if participants decided 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 during titration. Participants continued to receive 300 mg BID for 12 weeks during maintenance. The total duration of the treatment was up to 16 weeks (Full Treatment Period) with dose tapered down if participants decided to discontinue the treatment.

Treatment:

Drug: Soticlestat