Feature|Articles|September 14, 2026

Zilganersen FAQs: What Clinicians Should Know About the First Approved Treatment for Alexander Disease

The FDA has approved zilganersen (Zanvastro), the first Alexander disease treatment, giving clinicians a disease-modifying option and a clearer framework for counseling patients across the full age and phenotype spectrum.

The FDA recently approved zilganersen injection (Zanvastro) for treating Alexander disease in pediatric and adult patients, marking the first approved therapy for this rare, progressive neurological disorder. For context, Alexander disease is caused by mutations producing abnormal glial fibrillary acidic protein (GFAP) and affects fewer than 1 in a million people; zilganersen is an antisense oligonucleotide administered by spinal canal injection every three months to reduce abnormal GFAP production before it accumulates and causes damage.