FDA Approves Ionis Pharma Drug, the First for Ultra-Rare Alexander Disease

The FDA has approved Ionis Pharmaceuticals' drug Zanvastro (zilganersen), the first treatment for ultra-rare Alexander disease, marking a significant commercial and regulatory milestone for Ionis, which plans to commercialize the drug in the U.S. while licensing ex-U.S. rights. Zanvastro is an antisense oligonucleotide therapy targeting GFAP protein production, with dosing every three months and an estimated U.S. patient population of 300, priced at $285,000 per dose.

This Wire brief sits within Fusion42's coverage of Biotech, and 15 sources have reported it between 3 Sep 2026 and 22 Sep 2026.