for people ages 2-21 (full criteria)
at San Francisco, California and other locations
study started
estimated completion



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.

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)


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.


Dravet Syndrome (DS) Drug Therapy Epilepsies, Myoclonic Syndrome Soticlestat


You can join if…

Open to people ages 2-21

  1. Has documented clinical diagnosis of Dravet Syndrome (DS).
  2. 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.
  3. Weighs ≥10 kg at the screening visit (Visit 1).
  4. 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.
  5. 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.

You CAN'T join if...

  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.


  • University of California Benioff Children's Hospital in progress, not accepting new patients
    San Francisco California 94143 United States
  • David Geffen School of Medicine at UCLA not yet accepting patients
    Los Angeles California 90095 United States


accepting new patients at some sites,
but this study is not currently recruiting here
Start Date
Completion Date
To obtain more information on the study, click here/on this link
Phase 3 Dravet Syndrome Research Study
Study Type
Expecting 142 study participants
Last Updated