Developmental and Epileptic Encephalopathy 1Phase 3EMERALDNCT07010471
A Clinical Trial for Participants With DEE to Assess Efficacy, Safety, Tolerability, and PK of Relutrigine
A Phase 3 study testing 1.0mg/kg/day PRAX-562 and 1.5mg/kg/day PRAX-562 in people with Developmental and Epileptic Encephalopathy 1, run by Praxis Precision Medicines at 11 sites in 3 countries.
Trial summary
A Phase 3, Randomized, Multi-Center, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of Relutrigine in Participants with Developmental and Epileptic Encephalopathies Followed by an Open-Label Extension Read more about this study
- Who is it for?
- Ages 2 to 65 years
- Conditions the study is for
- Developmental and Epileptic Encephalopathy 1
- What is being tested?
- 1.0mg/kg/day PRAX-562 and 1.5mg/kg/day PRAX-562
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 160 participants
- Where
- 11 sitesin 3 countries
- Study dates
- 9 Jul 2025to Nov 2027
- 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 2 to 65 years
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Has a documented diagnosis of a developmental and epileptic encephalopathy.
- Onset of seizures <12 years old.
- Has a weight >7 kg at the time of signing consent/assent.
Who cannot join
- Has a history of left bundle branch block, arrhythmias, Brugada syndrome, congenital heart disease, familial short QT syndrome, or family history of sudden death or ventricular arrhythmias, including idiopathic ventricular fibrillation.
- Had 2 or more episodes of convulsive status epilepticus requiring hospitalization and intubation in the 6 months prior to Screening.
- Has an abnormal ECG reading, including a QT interval corrected for heart rate using Bazett's method (QTcB) <350 and >450 ms (males), or <360 and >460 ms (females) at Screening and/or on Day 1.
- Any nerve stimulation must have been placed at least 3 months prior to Screening with at least 1 month of stable settings prior to Screening.
- Has received any other 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 or within 5 half-lives of the last study drug dose.
Trial locations and contacts
11 sites in 3 countries.
11 sites in 3 countries
United States6 sites
Praxis Research Site
Chevy Chase, Maryland, 20815
Praxis Research Site
Gulf Breeze, Florida, 32561
Praxis Research Site
Hackensack, New Jersey, 07601
Praxis Research Site
La Jolla, California, 92037
Praxis Research Site
Philadelphia, Pennsylvania, 19104
Praxis Research Site
Roseville, Minnesota, 55113
Brazil4 sites
Praxis Research Site
Paraná, 80250
Praxis Research Site
Rio de Janeiro, 20231
Praxis Research Site
Rio Grande, Do Sul, 90610
Praxis Research Site
São Paulo, 15090
About this study
Official title: A Phase 3, Randomized, Multi-Center, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of Relutrigine in Participants With DEE Followed by an Open-Label Extension
A Phase 3, Randomized, Multi-Center, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of Relutrigine in Participants with Developmental and Epileptic Encephalopathies Followed by an Open-Label Extension
- Being tested
- 1.0mg/kg/day PRAX-562, 1.5mg/kg/day PRAX-562, Placebo
- Keywords
- DEE, Developmental and Epileptic Encephalopathy, epilepsy
- Medical subject headings
- Infantile Epileptic-Dyskinetic Encephalopathy, Epilepsy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
1.0mg/kg/day PRAX-562Drug
Also called relutrigine
Once daily orally or gastronomy/jejunostomy
1.5mg/kg/day PRAX-562Drug
Once daily orally or gastronomy/jejunostomy
PlaceboDrug
Once daily orally or gastronomy/jejunostomy
| Study group | Role | What they receive |
|---|---|---|
| Part A: Double-Blind Treatment Period | Experimental | Eligible participants will be randomly assigned in a double-blind manner and a 1:1 ratio to receive 1.0mg-1.5mg/kg relutrigine or placebo once daily orally or gastronomy/jejunostomy for 16 weeks Receives: Drug: 1.0mg/kg/day PRAX-562; Drug: 1.5mg/kg/day PRAX-562 |
| Part A: Double-Blind Treatment Period (Placebo) | Placebo comparator | Eligible participants will be randomly assigned in a double-blind manner and a 1:1 ratio to receive 1.0mg-1.5mg/kg relutrigine or placebo once daily orally or gastronomy/jejunostomy for 16 weeks Receives: Drug: Placebo |
| Part B: Open-Label Extension Treatment Period | Experimental | Participants from Part A will have the option to rollover to Part B to receive 1.0mg-1.5mg/kg of relutrigine once daily orally or gastronomy/jejunostomy for 32 weeks Receives: Drug: 1.0mg/kg/day PRAX-562; Drug: 1.5mg/kg/day PRAX-562 |
What is being measured
The primary outcome is the main question the study is designed to answer.
To assess the effect of relutrigine on seizure frequency in participants with DEEs compared to placebo
Change from baseline in monthly motor seizure frequency
Measured: 16 weeks
Secondary outcomes (14)
Achieve >50% reduction in monthly seizure frequency from baseline
Proportion of patients achieving >50% reduction in monthly seizure frequency from baseline
Measured: 16 weeks
Change in seizure-free days
Change in seizure-free days from baseline
Measured: 16 weeks
Clinical Global Impression-Severity questionnaire
CGI-S at baseline after 16 weeks
Measured: 16 weeks
Clinical Global Impression-Improvement questionnaire
CGI-I subdomains scores after 16 weeks
Measured: 16 weeks
Caregiver Global Impression-Severity questionnaire
CgGI-S at baseline after 16 weeks
Measured: 16 weeks
Caregiver Global Impression-Improvement questionnaire
CgGI-I subdomains scores after 16 weeks
Measured: 16 weeks
To evaluate the safety and tolerability of relutrigine in participants with DEEs
Incidence and severity of TEAEs
Measured: 16 weeks
Columbia-Suicide Severity Rating Scale questionnaire
Incidence of suicidal ideation or behavior as measured by the C-SSRS
Measured: 16 weeks
Evaluate the safety and tolerability of relutrigine in participants with DEEs
Incidence of clinically significant ECG abnormalities
Measured: 16 weeks
To evaluate the safety labs and tolerability of relutrigine in participants with DEEs
The principal investigator (PI) or sub investigator will review the laboratory report and document this review. Any clinically significant adverse changes occurring during the clinical trial will be documented as adverse events.
Measured: 16 weeks
To evaluate the change in respiratory rate and tolerability of relutrigine in participants with DEEs
Change in respiratory rate in breaths per minute
Measured: 16 weeks
To evaluate the change in blood pressure and tolerability of relutrigine in participants with DEEs
Change in blood pressure in mm/Hg
Measured: 16 weeks
To evaluate the change in pulse and tolerability of relutrigine in participants with DEEs
Change in heart rate in beats per minute
Measured: 16 weeks
To evaluate the change in body temperature and tolerability of relutrigine in participants with DEEs
Change in tympanic temperature in Celsius
Measured: 16 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Jun 2025
- Study start9 Jul 2025
- Primary completionDec 2026 (estimated)
- Study completionNov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Developmental and Epileptic Encephalopathy 1Studies 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
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 160 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
- NCT07010471
- Sponsor's protocol ID
- PRAX-562-311
- Acronym
- EMERALD
- Status last verified
- Jul 2026
- First submitted
- 30 May 2025
- Last updated
- 4 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 4 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3, Randomized, Multi-Center, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of Relutrigine in Participants With DEE Followed by an Open-Label Extension
- ClinicalTrials.gov ID
- NCT07010471
- Acronym / sponsor ID
- EMERALD / PRAX-562-311
- Keywords
- DEE, Developmental and Epileptic Encephalopathy, epilepsy
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 160 participants (estimated)
- Lead sponsor
- Praxis Precision MedicinesIndustry (pharma, biotech, devices)
- Study start
- 9 Jul 2025 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Nov 2027 (estimated)
- First posted
- 8 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 Phase 3, Randomized, Multi-Center, Double-Blind, Placebo-Controlled Clinical Trial to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of Relutrigine in Participants with Developmental and Epileptic Encephalopathies Followed by an Open-Label Extension
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Part A: Double-Blind Treatment Period | Experimental | Drug: 1.0mg/kg/day PRAX-562, Drug: 1.5mg/kg/day PRAX-562Eligible participants will be randomly assigned in a double-blind manner and a 1:1 ratio to receive 1.0mg-1.5mg/kg relutrigine or placebo once daily orally or gastronomy/jejunostomy for 16 weeks |
| Part A: Double-Blind Treatment Period (Placebo) | Placebo comparator | Drug: PlaceboEligible participants will be randomly assigned in a double-blind manner and a 1:1 ratio to receive 1.0mg-1.5mg/kg relutrigine or placebo once daily orally or gastronomy/jejunostomy for 16 weeks |
| Part B: Open-Label Extension Treatment Period | Experimental | Drug: 1.0mg/kg/day PRAX-562, Drug: 1.5mg/kg/day PRAX-562Participants from Part A will have the option to rollover to Part B to receive 1.0mg-1.5mg/kg of relutrigine once daily orally or gastronomy/jejunostomy for 32 weeks |
Who may qualify
- Ages
- 2 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (3 listed)
- Has a documented diagnosis of a developmental and epileptic encephalopathy.
- Onset of seizures <12 years old.
- Has a weight >7 kg at the time of signing consent/assent.
Key exclusion criteria (6 listed)
- Has a history of left bundle branch block, arrhythmias, Brugada syndrome, congenital heart disease, familial short QT syndrome, or family history of sudden death or ventricular arrhythmias, including idiopathic ventricular fibrillation.
- Had 2 or more episodes of convulsive status epilepticus requiring hospitalization and intubation in the 6 months prior to Screening.
- Has an abnormal ECG reading, including a QT interval corrected for heart rate using Bazett's method (QTcB) <350 and >450 ms (males), or <360 and >460 ms (females) at Screening and/or on Day 1.
- Any nerve stimulation must have been placed at least 3 months prior to Screening with at least 1 month of stable settings prior to Screening.
- Has received any other 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.
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 |
|---|---|---|
| 1.0mg/kg/day PRAX-562Also: relutrigineOnce daily orally or gastronomy/jejunostomy | Drug | Part A: Double-Blind Treatment Period, Part B: Open-Label Extension Treatment Period |
| 1.5mg/kg/day PRAX-562Once daily orally or gastronomy/jejunostomy | Drug | Part A: Double-Blind Treatment Period, Part B: Open-Label Extension Treatment Period |
| PlaceboOnce daily orally or gastronomy/jejunostomy | Drug | Part A: Double-Blind Treatment Period (Placebo) |
Primary outcome
To assess the effect of relutrigine on seizure frequency in participants with DEEs compared to placebo
Time frame: 16 weeks
Change from baseline in monthly motor seizure frequency
14 secondary outcomes
Achieve >50% reduction in monthly seizure frequency from baseline
Time frame: 16 weeks
Change in seizure-free days
Time frame: 16 weeks
Clinical Global Impression-Severity questionnaire
Time frame: 16 weeks
Clinical Global Impression-Improvement questionnaire
Time frame: 16 weeks
Caregiver Global Impression-Severity questionnaire
Time frame: 16 weeks
Caregiver Global Impression-Improvement questionnaire
Time frame: 16 weeks
To evaluate the safety and tolerability of relutrigine in participants with DEEs
Time frame: 16 weeks
Columbia-Suicide Severity Rating Scale questionnaire
Time frame: 16 weeks
Evaluate the safety and tolerability of relutrigine in participants with DEEs
Time frame: 16 weeks
To evaluate the safety labs and tolerability of relutrigine in participants with DEEs
Time frame: 16 weeks
To evaluate the change in respiratory rate and tolerability of relutrigine in participants with DEEs
Time frame: 16 weeks
To evaluate the change in blood pressure and tolerability of relutrigine in participants with DEEs
Time frame: 16 weeks
To evaluate the change in pulse and tolerability of relutrigine in participants with DEEs
Time frame: 16 weeks
To evaluate the change in body temperature and tolerability of relutrigine in participants with DEEs
Time frame: 16 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 4 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. This study is not recruiting at the moment.
Medical Director study director
Praxis Precision Medicines
11 sites in 3 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing 1.0mg/kg/day PRAX-562 and 1.5mg/kg/day PRAX-562 in people with Developmental and Epileptic Encephalopathy 1, run by Praxis Precision Medicines at 11 sites in 3 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 6 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: under way, not looking for participants, as of the sponsor's last update on 4 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 11 sites in United States, Brazil, Australia. 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. Some participants in this study may receive a placebo. 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?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To assess the effect of relutrigine on seizure frequency in participants with DEEs compared to placebo (time frame: 16 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 4 Aug 2026.