# FDA approval of Zanvastro for Alexander disease > Live situation record from CLSTR: https://clstr.news/situations/fda-approval-of-zanvastro-for-alexander-disease > Updated: 2026-09-08T08:59:01.000Z. Sources: 6. Developments: 2. The US Food and Drug Administration (FDA) has approved Zanvastro (zilganersen), developed by Ionis Pharmaceuticals, as the first disease-modifying treatment for Alexander disease (AxD). The therapy is indicated for both pediatric and adult patients. Alexander disease is a rare, progressive neurodegenerative disorder caused by mutations in the GFAP gene, which results in the toxic accumulation of glial fibrillary acidic protein in astrocytes. This buildup can lead to seizures, muscle weakness, and impaired movement. Clinical trial data indicated that the antisense oligonucleotide treatment, administered via quarterly intrathecal injections, targets the underlying biological cause of the disease. In patients aged five and older, the treatment demonstrated a statistically significant stabilization of gait speed compared to control groups. In children aged two to four, the therapy showed improvements in gross motor function. ## Timeline ### 2026-09-08: FDA approves Zanvastro for Alexander disease treatment The FDA has approved Zanvastro (zilganersen), the first disease-modifying therapy for Alexander disease, targeting the underlying genetic cause of this rare neurodegenerative disorder. 3 sources. https://clstr.news/cluster/fda-approves-zanvastro-for-alexander-disease-treatment ### 2026-09-04: Ionis Pharmaceuticals receives FDA approval for Alexander disease treatment The FDA has approved Ionis Pharmaceuticals’ Zanvastro, the first disease-modifying treatment for the rare and often fatal neurological disorder Alexander disease. 3 sources. https://clstr.news/cluster/ionis-pharmaceuticals-receives-fda-approval-for-alexander-disease-treatment --- Cite as: FDA approval of Zanvastro for Alexander disease. CLSTR, https://clstr.news/situations/fda-approval-of-zanvastro-for-alexander-disease