A Clinical Trial of PRAX-222 in Pediatric Participants With Early Onset SCN2A Developmental and Epileptic Encephalopathy

Inclusion Criteria:

• Has onset of seizures prior to 3 months of age.

• Has a minimum weight of at least 10 kg at screening.

• Has a documented SCN2A variant through genetic testing obtained via a laboratoryaccredited per Clinical Laboratory Improvement Amendments (CLIA) or College ofAmerican Pathologists (CAP) or equivalent.

• Additional inclusion criteria apply and will be assessed by the study team

Exclusion Criteria:

• Has any clinically significant or known pathogenic genetic variant other than in theSCN2A gene, or a genetic variant that may explain or contribute to the participant'sepilepsy and/or developmental disorder.

• Is taking more than 2 sodium channel blocking anti-seizure medications

• Additional exclusion criteria apply and will be assessed by the study team