Epileptic EncephalopathyPhase 3NCT07019922
A Clinical Trial of Elsunersen in Pediatric SCN2A-DEE to Assess Efficacy and Safety
A Phase 3 study testing 1mg elsunersen and 0.5mg elsunersen in people with Epileptic Encephalopathy and SCN2A Encephalopathy, run by Praxis Precision Medicines at 10 sites in 4 countries.
Trial summary
A Multi-Center, Single-Arm Clinical Trial to Investigate the Efficacy and Safety of Elsunersen in Pediatric Participants with Early Onset SCN2A Developmental and Epileptic Encephalopathy Read more about this study
- Who is it for?
- Ages 1 day to 18 years
- Conditions the study is for
- Epileptic Encephalopathy, SCN2A Encephalopathy
- What is being tested?
- 1mg elsunersen and 0.5mg elsunersen
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 10 sitesin 4 countries
- Study dates
- 13 Aug 2025to Dec 2028
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 1 day to 18 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
10 sites in 4 countries. Contact the study team or a site near you to ask about taking part.
10 sites in 4 countries
United States6 sites, 6 recruiting
- Recruiting
Praxis Research Site
Aurora, Colorado, 80045
- Recruiting
Praxis Research Site
Chicago, Illinois, 60612
- Recruiting
Praxis Research Site
Cincinnati, Ohio, 45229
- Recruiting
Praxis Research Site
Memphis, Tennessee, 38105
- Recruiting
Praxis Research Site
Philadelphia, Pennsylvania, 19104
- Recruiting
Praxis Research Site
San Diego, California, 92123
Brazil2 sites
- Withdrawn
Praxis Research Site
Porto Alegre, 90035
- Withdrawn
Praxis Research Site
São Paulo, 05403
About this study
Official title: A Multi-Center, Single-Arm Clinical Trial to Investigate the Efficacy and Safety of Elsunersen in Pediatric Participants With Early Onset SCN2A Developmental and Epileptic Encephalopathy
A Multi-Center, Single-Arm Clinical Trial to Investigate the Efficacy and Safety of Elsunersen in Pediatric Participants with Early Onset SCN2A Developmental and Epileptic Encephalopathy
- Conditions
- Epileptic Encephalopathy, SCN2A Encephalopathy
- Being tested
- 1mg elsunersen, 0.5mg elsunersen
- Keywords
- epilepsis, early onset scn2a, epileptic encephalopathy, scn2a, gain of function, seizure
- Medical subject headings
- Epilepsy, Seizures
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
1mg elsunersenDrug
24 weeks every 4 weeks intrathecally
0.5mg elsunersenDrug
24 weeks every 4 weeks intrathecally
| Study group | Role | What they receive |
|---|---|---|
| Cohort 1 Arm 1: Open-Label Treatment Period | Experimental | Open-label elsunersen Receives: Drug: 1mg elsunersen |
| Cohort 2: Open-Label Treatment Period | Experimental | Open-label elsunersen Receives: Drug: 1mg elsunersen |
| Cohort 3: Open-Label Treatment Period | Experimental | Open-label elsunersen Receives: Drug: 0.5mg elsunersen |
What is being measured
The primary outcome is the main question the study is designed to answer.
To assess the efficacy of elsunersen on seizure frequency in participants with early-onset SCN2A DEE
Median percent change in monthly (28 days) motor seizure frequency from baseline to treatment after 24 weeks
Measured: 24 weeks
Secondary outcomes (8)
To assess secondary efficacy outcomes of elsunersen in participants with early-onset SCN2A DEE
Responder rate - defined as a ≥50% reduction in monthly seizure frequency from baseline compared to treatment after 24 weeks
Measured: 24 weeks
To assess secondary efficacy outcomes of elsunersen in participants with early-onset SCN2A DEE
Change in motor seizure-free days from baseline
Measured: 24 weeks
CGI-S change 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).
Measured: 24 weeks
CGI subdomain scores at each postdose time point
Clinical Global Impression-Improvement (CGI-I) subdomains scores at each postdose time point
Measured: 24 weeks
CgGI-S from baseline
Caregiver Global Impression-Severity (CgGI-S) at baseline compared to treatment after 24 weeks
Measured: 24 weeks
CgGI-I subdomain scores at each postdose time point
Caregiver Global Impression-Improvement (CgGI I) subdomains scores at each postdose time point
Measured: 24 weeks
Sleep assessment scores from baseline
Sleep assessment scores at baseline compared to each postdose time point
Measured: 24 weeks
To evaluate the safety and tolerability of elsunersen in participants with early-onset SCN2A DEE
Incidence and severity of treatment-emergent adverse events (TEAEs)
Measured: 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Jun 2025
- Study start13 Aug 2025
- Primary completionDec 2026 (estimated)
- Study completionDec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Epileptic EncephalopathyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Model description
- Specific milestones have to be met in Cohort 1 for enrollment to open in Cohort 2 and the same will apply to open Cohort 3.
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Praxis Precision Medicines
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Praxis Precision Medicines
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07019922
- Sponsor's protocol ID
- PRAX-222-311
- Status last verified
- Jul 2026
- First submitted
- 5 Jun 2025
- Last updated
- 3 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Multi-Center, Single-Arm Clinical Trial to Investigate the Efficacy and Safety of Elsunersen in Pediatric Participants With Early Onset SCN2A Developmental and Epileptic Encephalopathy
- ClinicalTrials.gov ID
- NCT07019922
- Acronym / sponsor ID
- PRAX-222-311
- Conditions
- Epileptic Encephalopathy, SCN2A Encephalopathy
- Keywords
- epilepsis, early onset scn2a, epileptic encephalopathy, scn2a, gain of function, seizure
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Praxis Precision MedicinesIndustry (pharma, biotech, devices)
- Study start
- 13 Aug 2025 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Dec 2028 (estimated)
- First posted
- 13 Jun 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A Multi-Center, Single-Arm Clinical Trial to Investigate the Efficacy and Safety of Elsunersen in Pediatric Participants with Early Onset SCN2A Developmental and Epileptic Encephalopathy
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- Specific milestones have to be met in Cohort 1 for enrollment to open in Cohort 2 and the same will apply to open Cohort 3.
| Arm | Type | Receives |
|---|---|---|
| Cohort 1 Arm 1: Open-Label Treatment Period | Experimental | Drug: 1mg elsunersenOpen-label elsunersen |
| Cohort 2: Open-Label Treatment Period | Experimental | Drug: 1mg elsunersenOpen-label elsunersen |
| Cohort 3: Open-Label Treatment Period | Experimental | Drug: 0.5mg elsunersenOpen-label elsunersen |
Who may qualify
- Ages
- 1 day to 18 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (3 listed)
- 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.
Key exclusion criteria (4 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 1mg elsunersen24 weeks every 4 weeks intrathecally | Drug | Cohort 1 Arm 1: Open-Label Treatment Period, Cohort 2: Open-Label Treatment Period |
| 0.5mg elsunersen24 weeks every 4 weeks intrathecally | Drug | Cohort 3: Open-Label Treatment Period |
Primary outcome
To assess the efficacy of elsunersen on seizure frequency in participants with early-onset SCN2A DEE
Time frame: 24 weeks
Median percent change in monthly (28 days) motor seizure frequency from baseline to treatment after 24 weeks
8 secondary outcomes
To assess secondary efficacy outcomes of elsunersen in participants with early-onset SCN2A DEE
Time frame: 24 weeks
To assess secondary efficacy outcomes of elsunersen in participants with early-onset SCN2A DEE
Time frame: 24 weeks
CGI-S change from baseline
Time frame: 24 weeks
CGI subdomain scores at each postdose time point
Time frame: 24 weeks
CgGI-S from baseline
Time frame: 24 weeks
CgGI-I subdomain scores at each postdose time point
Time frame: 24 weeks
Sleep assessment scores from baseline
Time frame: 24 weeks
To evaluate the safety and tolerability of elsunersen in participants with early-onset SCN2A DEE
Time frame: 24 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Aug 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Medical Director study director
Praxis Precision Medicines
10 sites in 4 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing 1mg elsunersen and 0.5mg elsunersen in people with Epileptic Encephalopathy and SCN2A Encephalopathy, run by Praxis Precision Medicines at 10 sites in 4 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 3 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 10 sites in United States, Brazil, Germany, Italy. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Head of Pharmacovigilance (617-300-8460, clinicaltrials@praxismedicines.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To assess the efficacy of elsunersen on seizure frequency in participants with early-onset SCN2A DEE (time frame: 24 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Aug 2026.