The FDA approved Ionis Pharmaceuticals’ antisense therapy zilganersen (Zanvastro) for Alexander disease in pediatric and adult patients, making it the first and only disease-modifying treatment for the ultra-rare neurodegenerative disorder. The approval gives Ionis its first wholly owned neurology commercial product. The therapy is designed to reduce GFAP production associated with Alexander disease. Ionis said the FDA decision was based on trial results showing statistically significant stabilization of gait speed on the 10-Meter Walk Test in patients aged 5 and older at week 61, with additional benefit signals in younger pediatric patients assessed using the Gross Motor Function Measure-88. Ionis also said Zanvastro will be available in the coming weeks and noted a rare pediatric disease priority review voucher. The company has set up an access program called Every Step to support insurance and patient needs. For the rare-disease pipeline, the move reinforces Ionis’ push to bring RNA-based platform medicines into neurology, while also setting expectations for adoption and payer coverage once the drug reaches clinics.