Ionis Pharmaceuticals, Inc. (NASDAQ:IONS) today announced that the first participant has been dosed in the Phase 1-2 ASCEND study of ION337, an investigational RNA-targeted medicine for people living with Dravet syndrome, a rare, severe and lifelong neurological disorder. Dravet syndrome typically begins in infancy and is associated with prolonged seizures, developmental delays, cognitive impairments and an increased risk of sudden death.

"The first participant to receive ION337 in the ASCEND study marks an important step toward advancing a potential disease modifying therapy for people living with Dravet syndrome," said Holly Kordasiewicz, Ph.D., executive vice president, chief development officer, Ionis. "ION337 is our first wholly owned medicine developed using Ionis’ advanced NMA technology, which is designed to enhance the potency of our medicines and potentially support infrequent intrathecal dosing of every six months or less. This milestone reflects a new wave of scientific innovation across Ionis’ advancing neurology pipeline for people living with serious neurological conditions. We look forward to advancing the development of ION337 alongside the Dravet syndrome community."

ASCEND (NCT07531745) is an open-label, Phase 1-2 study evaluating the safety and tolerability of ION337 in children aged 2 to 12 years with a clinical diagnosis of Dravet syndrome. The study consists of two parts: an initial 6-month single ascending dose (SAD) component, followed by a 24-month multiple ascending dose (MAD) component with dosing of ION337 every 6 months, and an additional 7-month safety follow-up period.

ION337 uses next-generation N-Methylacetamide modifications (NMA technology) designed to enhance the potency of splice modulating antisense oligonucleotides (ASOs). This advanced molecular design is intended to provide sustained activity, supporting infrequent dosing.