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On April 6, 2026, Praxis Precision Medicines announced topline results from the EMBRAVE Part A clinical trial — and the findings represent a meaningful step forward for the SCN2A community.
The trial evaluated Elsunersen (also known as PRAX-222), an antisense oligonucleotide (ASO) therapy designed specifically for children with early-onset SCN2A developmental and epileptic encephalopathy (DEE) caused by GOF mutations. Here is what the results showed, what they mean, and what comes next.
If you are new to the SCN2A conversation, it helps to start with the basics. To learn more about SCN2A and how mutations affect the brain, visit our dedicated resource page. In short: the SCN2A gene provides instructions for building a sodium channel protein called Nav1.2, which helps brain cells communicate. When a mutation causes this channel to be overactive — a gain-of-function (GOF) variant — it can lead to severe, early-onset seizures and developmental challenges.
An antisense oligonucleotide (ASO) is a short, synthetic strand of genetic material designed to target and reduce the activity of a specific gene. Think of it as a precision dimmer switch: rather than turning a gene fully off, an ASO is engineered to dial it down to a more manageable level.
ASO therapies have been successfully developed for other rare neurological conditions. Elsunersen applies this same approach specifically to the SCN2A gene.
Preclinical studies of Elsunersen reported by Praxis have demonstrated reduction in both SCN2A gene expression and protein levels in vitro. In vivo, Elsunersen has shown dose-dependent seizure reduction, improvement in behavioral and locomotor activity, and increased survival in SCN2A mouse models.
Elsunersen is designed to reduce SCN2A gene expression — which is the right therapeutic direction for GOF mutations, where the channel is overactive. It is not appropriate for loss-of-function (LOF) mutations, where the channel is already underactive. Mutation type drives treatment direction, which is why genetic testing and specialist guidance are essential parts of every SCN2A care plan.
EMBRAVE Part A is a randomized, placebo-controlled Phase 1/2 clinical trial that evaluated the safety and efficacy of ascending doses of Elsunersen in pediatric patients with SCN2A DEE. The SCN2A research landscape has been building toward trials like this for years.
Nine patients between the ages of 2 and 12 with early-seizure-onset SCN2A DEE were enrolled. Patients were randomly assigned in a 3:1 ratio to receive either Elsunersen or a sham procedure.
Participants received treatment every four weeks for 24 weeks. Each patient received a starting dose of 1 mg, with optional dose escalation based on observed seizure reduction and individual tolerability. Following the 24-week controlled period, all nine patients continued into an open-label extension (OLE) — meaning every participant, including those initially on placebo, had the opportunity to receive Elsunersen. OLE data extended follow-up to up to one year.
The results from EMBRAVE Part A were reported by Praxis Precision Medicines on April 6, 2026. All figures below are drawn directly from that announcement.
Elsunersen demonstrated a 77% placebo-adjusted seizure reduction from baseline (p=0.015, 95% CI [33, 92]).
By period 6 of the trial, 71% of elsunersen-treated patients achieved greater than 50% seizure reduction. Additionally, 57% of patients experienced at least one 28-day period of complete seizure freedom — a milestone that carries profound meaning for families who live through daily or near-daily seizures.
Efficacy was sustained in the open-label extension (OLE) for up to one year.
One of the most striking findings extended beyond seizure counts. 100% of elsunersen-treated patients showed improvements in at least one of the following areas: sleep, motor function, muscle tone, attention, or neuropsychomotor development. No patients in the placebo group had additional improvements in these areas.
For caregivers who know that SCN2A affects far more than seizure frequency, this finding speaks directly to quality of life — not just seizure logs.
Elsunersen was reported to be well-tolerated in EMBRAVE Part A. Key safety findings from the trial announcement include:
As with all clinical trials, these results come from a small, carefully selected patient group. They are meaningful — and they will need to be replicated in the larger EMBRAVE3 study before regulatory conclusions can be drawn.
Praxis has confirmed that the pivotal EMBRAVE3 study is already underway. EMBRAVE3 is the larger, placebo-controlled trial designed to generate the confirmatory data needed to support a potential regulatory submission.
Elsunersen has received Orphan Drug Designation (ODD) and Rare Pediatric Disease Designation (RPDD) from the FDA, as well as ODD and PRIME designation from the European Medicines Agency — regulatory recognitions that acknowledge the seriousness of SCN2A DEE and support an accelerated development pathway.
If you want to join the fight to accelerate SCN2A therapies, there are meaningful ways to be part of this moment — from participating in research to supporting the Foundation's mission.
EMBRAVE Part A is a Phase 1/2 trial. Elsunersen is not yet approved. It is not available outside of clinical trials at this time. At the same time, the results are genuinely encouraging. A 77% placebo-adjusted seizure reduction in a randomized, controlled trial — sustained for up to a year — alongside broad developmental improvements across all treated patients is a signal the community has been working toward for years.
SCN2A research is moving. Families deserve to know that.
Every family navigating an SCN2A diagnosis deserves answers, community, and hope. The work to find them depends on your support. Please consider signing up for our patient registry and making a donation to help fund the research and resources that move us all forward.
This content is provided for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. Elsunersen is an investigational therapy and is not approved for general use. Always consult a qualified neurologist or healthcare provider regarding your child’s specific diagnosis, mutation type, and care plan.
1. Praxis Precision Medicines. “Praxis Precision Medicines Announces Positive Results from the EMBRAVE Part A Trial of Elsunersen in Patients with SCN2A Early-Onset Developmental and Epileptic Encephalopathy.” April 6, 2026. https://ir.praxismedicines.com/news-releases/news-release-details/praxis-precision-medicines-announces-positive-results-embrave
2. EMBRAVE3 Study Information. https://www.embravestudy.com/
3. Praxis Precision Medicines — Elsunersen Resources and Publications. https://praxismedicines.com/resources
4. ClinicalTrials.gov — Elsunersen Studies. https://clinicaltrials.gov/search?term=elsunersen
5. NIH NINDS — Epilepsy Information. https://www.ninds.nih.gov/health-information/disorders/epilepsy
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On April 6, 2026, Praxis Precision Medicines announced topline results from the EMBRAVE Part A clinical trial — and the findings represent a meaningful step forward for the SCN2A community.
The trial evaluated Elsunersen (also known as PRAX-222), an antisense oligonucleotide (ASO) therapy designed specifically for children with early-onset SCN2A developmental and epileptic encephalopathy (DEE) caused by GOF mutations. Here is what the results showed, what they mean, and what comes next.
If you are new to the SCN2A conversation, it helps to start with the basics. To learn more about SCN2A and how mutations affect the brain, visit our dedicated resource page. In short: the SCN2A gene provides instructions for building a sodium channel protein called Nav1.2, which helps brain cells communicate. When a mutation causes this channel to be overactive — a gain-of-function (GOF) variant — it can lead to severe, early-onset seizures and developmental challenges.
An antisense oligonucleotide (ASO) is a short, synthetic strand of genetic material designed to target and reduce the activity of a specific gene. Think of it as a precision dimmer switch: rather than turning a gene fully off, an ASO is engineered to dial it down to a more manageable level.
ASO therapies have been successfully developed for other rare neurological conditions. Elsunersen applies this same approach specifically to the SCN2A gene.
Preclinical studies of Elsunersen reported by Praxis have demonstrated reduction in both SCN2A gene expression and protein levels in vitro. In vivo, Elsunersen has shown dose-dependent seizure reduction, improvement in behavioral and locomotor activity, and increased survival in SCN2A mouse models.
Elsunersen is designed to reduce SCN2A gene expression — which is the right therapeutic direction for GOF mutations, where the channel is overactive. It is not appropriate for loss-of-function (LOF) mutations, where the channel is already underactive. Mutation type drives treatment direction, which is why genetic testing and specialist guidance are essential parts of every SCN2A care plan.
EMBRAVE Part A is a randomized, placebo-controlled Phase 1/2 clinical trial that evaluated the safety and efficacy of ascending doses of Elsunersen in pediatric patients with SCN2A DEE. The SCN2A research landscape has been building toward trials like this for years.
Nine patients between the ages of 2 and 12 with early-seizure-onset SCN2A DEE were enrolled. Patients were randomly assigned in a 3:1 ratio to receive either Elsunersen or a sham procedure.
Participants received treatment every four weeks for 24 weeks. Each patient received a starting dose of 1 mg, with optional dose escalation based on observed seizure reduction and individual tolerability. Following the 24-week controlled period, all nine patients continued into an open-label extension (OLE) — meaning every participant, including those initially on placebo, had the opportunity to receive Elsunersen. OLE data extended follow-up to up to one year.
The results from EMBRAVE Part A were reported by Praxis Precision Medicines on April 6, 2026. All figures below are drawn directly from that announcement.
Elsunersen demonstrated a 77% placebo-adjusted seizure reduction from baseline (p=0.015, 95% CI [33, 92]).
By period 6 of the trial, 71% of elsunersen-treated patients achieved greater than 50% seizure reduction. Additionally, 57% of patients experienced at least one 28-day period of complete seizure freedom — a milestone that carries profound meaning for families who live through daily or near-daily seizures.
Efficacy was sustained in the open-label extension (OLE) for up to one year.
One of the most striking findings extended beyond seizure counts. 100% of elsunersen-treated patients showed improvements in at least one of the following areas: sleep, motor function, muscle tone, attention, or neuropsychomotor development. No patients in the placebo group had additional improvements in these areas.
For caregivers who know that SCN2A affects far more than seizure frequency, this finding speaks directly to quality of life — not just seizure logs.
Elsunersen was reported to be well-tolerated in EMBRAVE Part A. Key safety findings from the trial announcement include:
As with all clinical trials, these results come from a small, carefully selected patient group. They are meaningful — and they will need to be replicated in the larger EMBRAVE3 study before regulatory conclusions can be drawn.
Praxis has confirmed that the pivotal EMBRAVE3 study is already underway. EMBRAVE3 is the larger, placebo-controlled trial designed to generate the confirmatory data needed to support a potential regulatory submission.
Elsunersen has received Orphan Drug Designation (ODD) and Rare Pediatric Disease Designation (RPDD) from the FDA, as well as ODD and PRIME designation from the European Medicines Agency — regulatory recognitions that acknowledge the seriousness of SCN2A DEE and support an accelerated development pathway.
If you want to join the fight to accelerate SCN2A therapies, there are meaningful ways to be part of this moment — from participating in research to supporting the Foundation's mission.
EMBRAVE Part A is a Phase 1/2 trial. Elsunersen is not yet approved. It is not available outside of clinical trials at this time. At the same time, the results are genuinely encouraging. A 77% placebo-adjusted seizure reduction in a randomized, controlled trial — sustained for up to a year — alongside broad developmental improvements across all treated patients is a signal the community has been working toward for years.
SCN2A research is moving. Families deserve to know that.
Every family navigating an SCN2A diagnosis deserves answers, community, and hope. The work to find them depends on your support. Please consider signing up for our patient registry and making a donation to help fund the research and resources that move us all forward.
This content is provided for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. Elsunersen is an investigational therapy and is not approved for general use. Always consult a qualified neurologist or healthcare provider regarding your child’s specific diagnosis, mutation type, and care plan.
1. Praxis Precision Medicines. “Praxis Precision Medicines Announces Positive Results from the EMBRAVE Part A Trial of Elsunersen in Patients with SCN2A Early-Onset Developmental and Epileptic Encephalopathy.” April 6, 2026. https://ir.praxismedicines.com/news-releases/news-release-details/praxis-precision-medicines-announces-positive-results-embrave
2. EMBRAVE3 Study Information. https://www.embravestudy.com/
3. Praxis Precision Medicines — Elsunersen Resources and Publications. https://praxismedicines.com/resources
4. ClinicalTrials.gov — Elsunersen Studies. https://clinicaltrials.gov/search?term=elsunersen
5. NIH NINDS — Epilepsy Information. https://www.ninds.nih.gov/health-information/disorders/epilepsy
Vlad Magdalin
