Praxis Introduces Breakthrough Elsunersen Therapy for Treating SCN2A Developmental and Epileptic Encephalopathy
Praxis Precision Medicines has introduced elsunersen (PRAX-222) for the treatment of seizures associated with SCN2A developmental and epileptic encephalopathy (SCN2A-DEE) caused by gain-of-function variants in the SCN2A gene.
Elsunersen is an investigational antisense oligonucleotide (ASO) designed to reduce SCN2A gene expression and target the underlying cause of early-seizure-onset SCN2A-DEE. The therapy is being developed to address seizures and other neurological symptoms associated with gain-of-function SCN2A mutations.
The designation is supported by results from the EMBRAVE Part A Phase 1/2 study involving nine children aged two to 12 years. Treatment with elsunersen resulted in a 77% sham-adjusted reduction in monthly seizures from baseline, while 71% of treated patients achieved more than a 50% reduction in seizures. More than half of the treated patients also experienced at least a 28-day period without seizures during the six-month treatment period.
SCN2A-DEE is a rare and severe genetic form of epilepsy caused by gain-of-function variants in the SCN2A gene. Seizures generally begin during infancy and can be accompanied by developmental impairment and other neurological complications. There are currently no approved treatments that directly address the underlying genetic cause of the condition.
The FDA’s Breakthrough Therapy Designation is intended to accelerate the development and regulatory review of medicines for serious conditions where preliminary clinical evidence indicates the potential for substantial improvement over existing therapies. Praxis is advancing elsunersen through the pivotal EMBRAVE3 study, which is evaluating approximately 30 patients using a single-arm, baseline-controlled design.
Elsunersen has also received Orphan Drug and Rare Pediatric Disease designations from the FDA, as well as Orphan Drug and PRIME designations from the European Medicines Agency. The therapy is being developed as a potential disease-modifying treatment for SCN2A-DEE.
