A Multicenter, Open-label, Pilot Study of Soticlestat (TAK-935/OV935) in Participants With 15Q Duplication Syndrome (Dup 15q) or Cyclin-Dependent Kinase-Like 5 (CDKL5) Deficiency Disorder (ARCADE STUDY)

A Multicenter, Open-label, Pilot Study of TAK-935 (OV935) in Patients With 15Q Duplication Syndrome or CDKL5 Deficiency Disorder (ARCADE Study)

The purpose of this study is to investigate the effect of soticlestat on the frequency of motor seizures for participants with Dup15q or CDD during the Maintenance Period.

The drug being tested in this study is called soticlestat. Soticlestat is being tested to treat people with Dup 15q or CDD. This study will assess the effects of TAK-935 on seizure frequency, safety.

The study will enroll approximately 30 participants. Participants will be enrolled into 2 groups based on their diagnosis as: Dup 15q or CDD.

All participants will be asked to take soticlestat tablets twice daily with or without food.

The study comprises of 2 periods: Screening/Baseline Period and Treatment Period (Dose Optimization and Maintenance). The overall time to participate in this study is approximately 30 weeks, including 4 to 6 weeks Screening/Baseline Period, 20 weeks Treatment Period, 2 weeks Taper, and 2 weeks safety follow up period. Participants completing this study will have an option to enroll in the open-label extension (OLE) study, under a separate protocol.

Inclusion Criteria:

1. Clinical diagnosis of Dup 15q or CDKL5 deficiency disorder.
2. Currently taking 1 to 6 antiepileptic drugs (AEDs) at a stable dose.

Exclusion Criteria:

1. Two or more episodes of convulsive status epilepticus per 3 months requiring hospitalization and intubation.
2. Currently receiving a study drug or participated in a clinical study involving another investigational product in the previous month.