A Clinical Trial of PRAX-562 in Subjects With Developmental and Epileptic Encephalopathies (DEE) (EMBOLD)

Praxis Precision Medicines

Status and phase

Enrolling

Phase 2

Conditions

SCN8A Encephalopathy

SCN2A Encephalopathy

Treatments

Drug: Part A: 0.5mg/kg/day PRAX-562 for 12 Weeks and Matching Placebo for 4 Weeks

Drug: Part B: 0.5mg/kg/day PRAX-562

Drug: Part A: 0.5mg/kg/day PRAX-562 for 16 Weeks

Study type

Interventional

Funder types

Industry

Identifiers

NCT05818553

PRAX-562-221

Details and patient eligibility

About

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.

Enrollment

20 estimated patients

Sex

All

Ages

2 to 18 years old

Volunteers

No Healthy Volunteers

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.

Trial design

Primary purpose

Treatment

Allocation

Randomized

Interventional model

Parallel Assignment

Masking

Triple Blind

20 participants in 2 patient groups

Part A: Randomized, Double-Blind 0.5mg/kg/day PRAX-562 or PRAX-562/Placebo

Experimental group

Description:

Eligible participants from each cohort will be randomized in a 1:1 ratio to either 0.5 milligrams/kilograms/day (mg/kg/day) PRAX-562 for 16 weeks (PRAX-562 arm) or 0.5 mg/kg/day PRAX-562 for 12 weeks and matching placebo for 4 weeks (PRAX-562/placebo arm) administered orally or via gastrostomy tube (G-tube).

Treatment: