Rare Disease Therapies Advance for Dravet Syndrome and Spinal Muscular Atrophy
New treatments for rare pediatric neurological conditions show promise, with zorevunersen reducing seizures in Dravet syndrome patients and an SMA therapy under FDA review following stem cell research breakthroughs.
A study published in the New England Journal of Medicine found that children and teenagers with Dravet syndrome who were treated with the medication zorevunersen experienced reductions in seizure frequency, more seizure-free days and significant improvements in quality of life and overall functioning. Separately, a treatment for the pediatric disease spinal muscular atrophy currently is under review by the U.S. Food and Drug Administration.
Dravet syndrome is a rare, severe form of epilepsy that begins in infancy, often with prolonged seizures triggered by fever. It is most commonly caused by mutations in the SCN1A gene and leads to frequent seizures, developmental delays and other neurological challenges. Treatment options remain limited for this lifelong condition.
Zorevunersen is an antisense oligonucleotide designed to target the SCN1A gene and increase production of the NaV1.1 protein, with the goal of addressing the underlying cause of the disease. The study, supported by Stoke Therapeutics, enrolled 81 participants with Dravet syndrome between the ages 2 to 18 who were receiving anti-seizure medications into two Phase 1/2a open-label multicenter trials – MONARCH and ADMIRAL.
Patients were put into two cohorts, a single-ascending-dose cohort or a multiple-ascending-dose cohort. Of the 81 participants, 75 who completed the Phase 1/2a trials and were eligible enrolled in open-label extension studies – LONGWING and SWALLOWTAIL – where treatment with zorevunersen continued.
The median reductions in seizure frequency were largest in patients who received multiple initial doses of 70mg of zorevunersen in the Phase 1/2a trials. Continued treatment in the extension studies was associated with stabilized reductions in the frequency of convulsive seizures through 36 months.
"In this trial, beyond seizure reduction, we observed improvements in quality of life and overall functioning that were reported by both clinicians and caregivers," said a pediatric neurologist at Children's National Hospital and co‑author of the study. "These outcomes are especially meaningful for individuals with Dravet syndrome and their families, given the broad and persistent impact of the disease."
Zorevunersen is currently being further evaluated in an ongoing Phase 3 clinical study in patients with Dravet syndrome.
The spinal muscular atrophy treatment under FDA review emerged from research led by a professor of Stem Cell and Regenerative Biology and director of the Stem Cell Research Program at Boston Children's Hospital, who won the 2026 March of Dimes Richard B Johnston Jr., MD Prize for pioneering work in hematology and stem cell biology.
The researcher was one of the first scientists to use zebrafish as model organisms for revealing new insights about human diseases, especially blood disorders and cancers in children. In 2007, the lab showed how the hormone prostaglandin E2 could dramatically boost stem cell populations in zebrafish. Later clinical trials showed that adding it to umbilical cord blood in humans also greatly increased the stem cell populations.
These discoveries improved transplant procedures for leukemia patients and these treatments now are routinely used for genetic blood diseases such as sickle cell anemia, thalassemia, and primary immunodeficiencies. The research has led to the development of a therapeutic for Diamond-Blackfan anemia that is nearing clinical trials.