Ionis Zilganersen Antisense Oligonucleotide for Alexander Disease PDUFA Target Date September 22, 2026
Ionis Pharmaceuticals (NASDAQ: IONS) awaits its September 22, 2026 PDUFA target action date for zilganersen (an intrathecally-administered antisense oligonucleotide designed to reduce production of glial fibrillary acidic protein / GFAP) for the treatment of Alexander disease, a rare autosomal dominant neurodegenerative disease caused by GFAP gene mutations. If approved, zilganersen would become the first FDA-approved therapy for Alexander disease and Ionis's next commercial launch following Wainua (eplontersen) for hereditary transthyretin amyloid polyneuropathy (with the CARDIO-TTransform ATTR-CM primary endpoint miss now behind the company). Zilganersen was granted FDA Fast Track designation and Orphan Drug designation. Alexander disease presents in infancy through adulthood with progressive motor and cognitive decline; no disease-modifying therapies are currently approved. Not a peptide, but the antisense oligonucleotide class continues to complement peptide-based rare-disease therapies (Rein Therapeutics LTI-03 Caveolin-1 peptide for IPF among others) as the RNA modality expands into ultra-orphan indications.