Recruiting

Elsunersen for Early Onset SCN2A Developmental and Epileptic Encephalopathy in Children

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What is being tested

1mg elsunersen

+ sham procedure
+ 0.5mg elsunersen
Drug
Procedure
Who is being recruted

Epileptic Encephalopathy

+ SCN2A Encephalopathy
Until 18 Years
+7 Eligibility Criteria

See all eligibility criteria

How is the trial designed

Treatment Study

Placebo-Controlled
Phase 3
Interventional
Study Start: August 2025

See protocol details

Summary

Principal SponsorPraxis Precision Medicines
Study ContactHead of Pharmacovigilance
Last updated: October 2, 2025
Sourced from a government-validated database.Claim as a partner
Study start date: August 13, 2025Actual date on which the first participant was enrolled.

This study is focused on understanding if a new treatment called Elsunersen can help children who have a rare condition known as early onset SCN2A developmental and epileptic encephalopathy. This condition affects the brain, causing developmental delays and seizures. The study is particularly important because children with this condition often face significant challenges and there are limited treatment options available. By testing Elsunersen, researchers hope to find a safe and effective treatment that could greatly improve the quality of life for these children and their families. Participants in the study will receive either the treatment, Elsunersen, or a placebo through a controlled procedure. The study is designed to carefully monitor the effects of the drug while ensuring neither the researchers nor the participants know who receives the actual treatment, maintaining a "double-blind" setup. This helps in accurately measuring how well Elsunersen works and checking for any side effects. Through these methods, the study aims to gather reliable data on the safety and effectiveness of this potential new treatment for children with this serious condition.

Official TitleA Randomized, Multi-Center, Double-Blind, Sham-Procedure-Controlled Clinical Trial to Investigate the Efficacy and Safety of Elsunersen in Pediatric Participants With Early Onset SCN2A Developmental and Epileptic Encephalopathy 
Principal SponsorPraxis Precision Medicines
Study ContactHead of Pharmacovigilance
Last updated: October 2, 2025
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details
50 patients to be enrolledTotal number of participants that the clinical trial aims to recruit.
Treatment Study
These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.

How participants are assigned to different groups/arms
In this clinical study, participants are placed into groups randomly, like flipping a coin. This ensures that the study is fair and unbiased, making the results more reliable. By assigning participants by chance, researchers can better compare treatments without external influences.

Other Ways to Assign Participants
Non-randomized allocation: Participants are assigned based on specific factors, such as their medical condition or a doctor's decision.
None (Single-arm trial): If the study has only one group, all participants receive the same treatment, and no allocation is needed.

How treatments are given to participants
Participants receive treatments one after another in a pre-planned sequence. The next treatment may depend on how the participant responds to the previous one.

Other Ways to Assign Treatments
Single-group assignment: Everyone gets the same treatment.
Parallel assignment: Participants are split into separate groups, each receiving a different treatment.
Cross-over assignment: Participants switch between treatments during the study.
Factorial assignment: Participants receive different combinations of treatments.
Other assignment: Treatment assignment does not follow a standard or predefined design.

How the effectiveness of the treatment is controlled
In a placebo-controlled study, some participants receive the experimental treatment, while others receive an inert substance (placebo) to compare outcomes. This method helps to isolate the effect of the treatment from the psychological effects of receiving any treatment at all.

Other Options
Non-placebo-controlled: No placebo is used. All participants receive the actual treatment or alternative interventions (often the Standard of Care), and comparisons are made between these treatments.

How the interventions assigned to participants is kept confidential
Participants, researchers, outcome assessors, and care providers do not know which treatment is being given. This is the most complete way to prevent bias and keep the study as neutral as possible.

Other Ways to Mask Information
Open-label: Everyone knows which treatment is being given.
Single-blind: Participants do not know which treatment they are receiving, but researchers do.
Double-blind: Neither participants nor researchers know which treatment is given.
Triple-blind: Participants, researchers, and outcome assessors do not know which treatment is given.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria
Any sexBiological sex of participants that are eligible to enroll.
Until 18 YearsRange of ages for which participants are eligible to join.
Healthy volunteers not allowedIf individuals who are healthy and do not have the condition being studied can participate.
Conditions
Pathology
Epileptic Encephalopathy
SCN2A Encephalopathy
Criteria
3 inclusion criteria required to participate
Has a documented Gain of Function SCN2A variant confirmed through genetic testing
Has onset of seizures prior to 3 months of age
Seizure frequency of 4 or more countable motor seizures per 28-day during the Baseline Observation Period
4 exclusion criteria prevent from participating
Has any clinically significant or known pathogenic genetic variant other than in the SCN2A gene, or a genetic variant that may explain or contribute to the participant's epilepsy and/or developmental disorder
Has bone, spine (eg, kyphosis, scoliosis), bleeding, or other disorder
Has received any experimental or investigational drug, device, or other therapy within 30 days or 5 half-lives (whichever is longer) prior to Screening, including any prior use of gene therapy
Is currently pregnant or breastfeeding or is planning to become pregnant during the clinical trial

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives
4 intervention groups 

are designated in this study

25% chance 

of being blinded to the placebo group

Treatment Groups
Group I
Experimental
Double-blind treatment period elsunersen
Group II
Sham
Double-blind sham-procedure
Group III
Experimental
Open-label elsunersen
Group IV
Experimental
Open-label elsunersen
Study Objectives
Primary Objectives

Median percent change in monthly (28 days) motor seizure frequency from baseline to treatment after 24 weeks
Secondary Objectives

Responder rate - defined as a ≥50% reduction in monthly seizure frequency from baseline compared to treatment after 24 weeks

Change in motor seizure-free days from baseline

CGI-S assesses the clinician's impression of the participant's current illness state. The clinician should use his/her total clinical experience with this patient population and rate the current severity on a 7-point scale from 1 (normal, not at all ill) to 7 (among the most extremely ill patients).

Clinical Global Impression-Improvement (CGI-I) subdomains scores at each postdose time point

Caregiver Global Impression-Severity (CgGI-S) at baseline compared to treatment after 24 weeks

Caregiver Global Impression-Improvement (CgGI I) subdomains scores at each postdose time point

Sleep assessment scores at baseline compared to each postdose time point

Incidence and severity of treatment-emergent adverse events (TEAEs)

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.
This study has 2 locations
Recruiting
Praxis Research SiteSan Diego, United StatesSee the location
Recruiting
Praxis Research SiteChicago, United States
Recruiting
2 Study Centers