An Open-Label Study to Investigate the Safety of Single Ascending Doses in Children and Adolescents With Dravet Syndrome

Open to people ages 2-18

• Must have DS with onset prior to 12 months of age with recurrent focal motor or hemiconvulsive or generalized tonic-clonic seizures, which are often prolonged and triggered by hyperthermia.
• No history of causal MRI lesion
• No other known etiology
• Normal development at seizure onset.
• Documented pathogenic, likely pathogenic variant, or variant of uncertain significance in the SCN1A gene associated with DS.
• Had at least 2 treatments for epilepsy that either had lack of adequate seizure control (requiring an additional AED) or had to be discontinued due to an AE(s).
• Currently be taking at least one AED at a dose which has been stable for at least 4 weeks prior to Screening.
• All epilepsy medications or interventions for epilepsy (including ketogenic diet or vagal nerve stimulator) must have been stable (including product type, dose, and setting) for at least 4 weeks prior to Screening.

• Known pathogenic mutation in another gene that causes epilepsy
• Currently being treated with an antiepileptic drug acting primarily as a sodium channel blocker including: phenytoin, carbamazepine, oxcarbazepine, lamotrigine, lacosamide, or rufinamide.
• Clinically significant unstable medical conditions other than epilepsy.
• Has had clinically relevant symptoms or a clinically significant illness in the 4 weeks prior to Screening or prior to dosing on Day 1, other than epilepsy.
• Any other significant disease or disorder which, in the opinion of the Investigator, may either put the patient at risk because of participation in the study, may influence the results of the study, or may affect the patient's ability to participate in the study.