A Clinical Study to Evaluate the Safety and Efficacy of ETX101, an AAV9-Delivered Gene Therapy in Children With SCN1A-positive Dravet Syndrome

EXPEDITION: A Clinical Study to Evaluate the Safety and Efficacy of ETX101, an AAV9-Delivered Gene Therapy in Children With SCN1A-positive Dravet Syndrome

EXPEDITION is a Phase 1/2 study in the UK to evaluate the safety and efficacy of ETX101 in participants with SCN1A-positive Dravet Syndrome aged 6 to < 48 months. The study follows and open-label, dose-escalation design.

Inclusion Criteria:

• Participant has a predicted loss of function pathogenic or likely pathogenic SCN1A variant
• Participant must have experienced their first seizure between the age of 3 and 15 months
• Participant must have a clinical diagnosis of Dravet syndrome or the treating clinician must have high clinical suspicion of a diagnosis of Dravet syndrome
• Participant is receiving at least one prophylactic antiseizure medication

Exclusion Criteria:

• Participant has another genetic mutation or clinical comorbidity which could potentially confound the typical Dravet phenotype
• Participant has a known central nervous system structural and/or vascular abnormality (indicated by an MRI or CT scan of the brain).
• Participant has an abnormality that may interfere with CSF distribution and/or has an existing ventriculoperitoneal shunt.
• Participant is currently taking or has taken antiseizure medications (ASMs) at a therapeutic dose that are contraindicated in Dravet syndrome, including sodium channel blockers.
• Participant has experienced seizure freedom for a period of 4 consecutive weeks within the 90-day period prior to informed consent.
• Participant has previously received gene or cell therapy.
• Participant is currently enrolled in a clinical trial or receiving an investigational therapy.
• Participant has clinically significant underlying liver disease.