Overview

This is a Phase 2, double-blind, randomized clinical trial to explore the safety, tolerability, efficacy, and pharmacokinetics of PRAX-562 in pediatric participants who have seizures associated with early-onset SCN2A-DEE and SCN8A-DEE.

Eligibility

Inclusion Criteria:

• Has a documented rare missense variant in SCN2A with onset of seizures occurring in the first three months of life or has a documented de novo (not observed in either parent) missense variant in SCN8A with onset of seizures occurring in the first six months of life.
• Has a seizure frequency as follows:
  • At least 8 countable motor seizures in the 4 weeks immediately prior to Screening as reported by the parent/legal guardian or in the opinion of the investigator AND
  • At least 8 countable motor seizures during the 28 day Baseline Observation Period (during which seizure frequency is recorded in a daily seizure diary).
• Additional inclusion criteria apply and will be assessed by the study team.

Exclusion Criteria:

• Has any clinically significant or known pathogenic or likely pathogenic genetic variant other than in SCN2A and SCN8A or a genetic variant that may explain or contribute to the participant's epilepsy and/or developmental disorder.
• Has a documented, functionally characterized loss-of-function (LoF) missense variant or a presumed LoF variant (nonsense or frameshift variant) based on genetic testing and/or clinical evidence that prior exposure to a sodium channel blocker (SCB) medication worsened seizures.
• Has 2 or more episodes of convulsive status epilepticus requiring hospitalization and intubation in the 6 months prior to Screening.
• Additional exclusion criteria apply and will be assessed by the study team.