Praxis Precision Medicines Inc. (NASDAQ:PRAX) said on Monday that the U.S. Food and Drug Administration granted Breakthrough Therapy Designation to elsunersen (PRAX-222), its investigational therapy for seizures associated with SCN2A developmental and epileptic encephalopathy (SCN2A-DEE) caused by gain-of-function variants in the SCN2A gene.
SCN2A-DEE is a rare genetic epilepsy that typically begins during infancy and is associated with severe developmental and neurological impairments.
The designation marks the third Breakthrough Therapy Designation for the company’s late-stage pipeline and is expected to accelerate the development and regulatory review process for the experimental treatment.
Marcio Souza, president and CEO of Praxis, said that results from the EMBRAVE Part A study support elsunersen’s potential to become the first disease-modifying, targeted therapy for patients with SCN2A gain-of-function disease.
Trial Data Show Significant Reduction In Seizures
The FDA’s decision was supported by topline findings from the randomized, sham-controlled Phase 1/2 EMBRAVE Part A trial, which evaluated ascending doses of elsunersen in nine pediatric patients aged 2 to 12 years with early-seizure-onset SCN2A-DEE.
According to Praxis, treatment with elsunersen resulted in a 77% sham-adjusted reduction in monthly seizures from baseline. Additionally, 71% of treated patients achieved more than a 50% reduction in seizures, while 57% experienced at least 28 consecutive days without seizures during the six-month treatment period.
The company said treatment benefits were maintained for up to one year in the ongoing open-label extension study.
Praxis also reported that all patients receiving elsunersen demonstrated improvements in at least one additional clinical measure, including sleep, motor function, muscle tone, attention, or neuropsychomotor development. No patients in the sham group experienced similar improvements.
EMBRAVE3 Study Continues Enrollment
The company said elsunersen was generally well tolerated, with no drug-related serious adverse events, no treatment discontinuations, and no signs of neuroinflammation at doses up to 8 milligrams. Most treatment-emergent adverse events were mild to moderate.
Following discussions with the FDA announced in December 2025, Praxis modified the pivotal EMBRAVE3 study to a single-arm, baseline-controlled design.
The study is currently enrolling approximately 30 patients, all of whom will receive elsunersen for 24 weeks followed by an additional 24-week treatment extension.
PRAX Price Action: Praxis Precision Medicine shares were up 4.70% at $295.58 at the time of publication on Monday, according to Benzinga Pro data.
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