Praxis Precision Medicines, Inc. (NASDAQ:PRAX) shares climbed 4% on Monday after the company announced that the U.S. Food and Drug Administration had granted Breakthrough Therapy Designation to elsunersen for the treatment of seizures linked to SCN2A Developmental and Epileptic Encephalopathy (SCN2A-DEE).
The regulatory milestone follows encouraging clinical data and is expected to support the continued development of the experimental therapy.
Positive Trial Results Supported FDA Decision
The designation was awarded based on findings from Part A of the EMBRAVE study, which evaluated elsunersen, an antisense oligonucleotide therapy designed to target the underlying genetic cause of the disorder.
According to the company, patients receiving treatment experienced a 77% reduction in monthly seizure frequency compared with the sham control group. The improvement was maintained during the open-label extension phase for up to one year.
Strong Seizure Reduction Observed in Pediatric Patients
The randomized, sham-controlled Phase 1/2 trial assessed escalating doses of elsunersen in nine pediatric patients between the ages of two and 12 who were diagnosed with early-seizure-onset SCN2A-DEE.
Results showed that 71% of treated patients achieved a reduction in seizure frequency of more than 50%, while 57% experienced at least one seizure-free period lasting 28 days or longer during the six-month treatment phase.
The data suggest the therapy may offer meaningful clinical benefits for patients suffering from this severe neurological disorder.
Pivotal EMBRAVE3 Study Continues Enrollment
Praxis said its registrational EMBRAVE3 trial is currently enrolling patients under a streamlined development pathway agreed with the FDA.
Following regulatory discussions completed in December 2025, the study design was modified to a single-arm, baseline-controlled format. All participants receive elsunersen for an initial 24-week treatment period, followed by an additional 24-week extension phase.
The company plans to enroll approximately 30 patients in the study.
Therapy Receives Multiple Regulatory Designations
Elsunersen has now secured several important regulatory designations aimed at accelerating development and review.
In the United States, the therapy has received Breakthrough Therapy Designation, Orphan Drug Designation and Rare Pediatric Disease Designation from the FDA.
In Europe, the treatment has been granted both Orphan Drug Designation and PRIME status by the European Medicines Agency.
Addressing a Significant Unmet Medical Need
Early-seizure-onset SCN2A-DEE is a rare and severe form of genetic epilepsy caused by gain-of-function mutations in the SCN2A gene.
The condition is associated with frequent seizures, developmental impairment and significant neurological challenges.
Currently, no approved therapies specifically target the underlying genetic cause of the disease, highlighting the potential importance of elsunersen if future clinical studies continue to demonstrate positive results.