A Clinical Study to Evaluate the Safety and Efficacy of ETX101 in Infants and Children with SCN1A-Positive Dravet Syndrome (ENDEAVOR)

Encoded Therapeutics

Status and phase: Enrolling; Phase 2; Phase 1

Conditions: Dravet Syndrome

Treatments: Drug: ETX101

Study type: Interventional

Funder types: Industry

Identifiers

NCT05419492

ETX-DS-002

Details and patient eligibility

About

ENDEAVOR is a Phase 1/2, 2-part, multicenter study to evaluate the safety and efficacy of ETX101 in participants with SCN1A-positive Dravet syndrome aged ≥6 to <36 months (Part 1) and aged ≥6 to <48 months (Part 2). Part 1 follows an open-label, dose-escalation design, and Part 2 is a randomized, double-blind, sham delayed-treatment control, dose-selection study.

Enrollment: 22 estimated patients

Sex: All

Ages: 6 to 47 months old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Participant must be aged between ≥6 months and <36 months in Part 1 and <48 months in Part 2.
• Participant must have a predicted loss of function pathogenic or likely pathogenic SCN1A variant.
• Participant must have experienced their first seizure between the ages of 3 and 15 months.
• Participant must have a clinical diagnosis of Dravet syndrome or the treating clinician must have a 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, including under an expanded access and/or compassionate use program.
• Participant has clinically significant underlying liver disease.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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22 participants in 2 patient groups

Part 1

Experimental group

Description:

Part 1 will follow an open-label, rule-based, dose-escalation design and will evaluate up to 4 dose levels of ETX101.

Treatment:

Drug: ETX101

Part 2

Sham Comparator group

Description:

Part 2 is a dose-selection study, which will follow a double-blind (up through Week 52), randomized, sham delayed-treatment control design. There will be up to 3 cohorts in Part 2. If it is determined two dose levels of ETX101 will be evaluated in Part 2, participants will be randomized 1:1:1 to study treatment or sham procedure with delayed treatment. If Part 2 proceeds with a single dose level of ETX101, participants will be randomized 2:1 to study treatment or sham procedure with delayed treatment.

Treatment:

Drug: ETX101