Zanvastro (zilganersen) for Alexander disease
What is being decided
Ionis Pharmaceuticals has a NDA under FDA review for Zanvastro (zilganersen) in Alexander disease. First and only treatment approved for Alexander disease, cleared ahead of its September 22nd target date. Ionis also received a Rare Pediatric Disease Priority Review Voucher.
Who this decision matters to
Alexander disease is a rare inherited leukodystrophy caused by mutations in the GFAP gene affecting astrocyte function. The condition leads to progressive neurological deterioration with abnormal protein accumulation in the central nervous system. Three clinical forms exist with varying age of onset and progression rate.
Prevalence: Approximately 1 in 100,000 to 200,000 people. See our full Alexander Disease page for current treatments, recruiting trials, and community resources.
About the drug
Zanvastro antisense oligonucleotide that reduces GFAP protein production Our full Zanvastro profile covers how it works, side effects in plain language, and its trial history.
Where Alexander Disease treatment stands today
The treatment landscape changed in September 2026, when the FDA approved Zanvastro (zilganersen) as the first treatment for Alexander disease. It is given as a spinal fluid injection once every 3 months and lowers production of GFAP, the protein that builds up in astrocytes and drives the disease. In its pivotal study, patients 5 and older held their walking speed steady over 61 weeks while the control group declined. Ask a neurologist experienced in leukodystrophies whether it is appropriate for you or your child. Clinical trials continue to investigate other approaches, including RNA interference strategies to reduce GFAP expression and agents modulating the glial response and neuroinflammation. Genetic counseling is important given autosomal dominant inheritance and the possibility of de novo mutations. Seizure management with appropriate antiepileptic drugs and supportive care maximize quality of life and neurological function. The United Leukodystrophy Foundation and Alexander Disease Information & Support Center connect patients with specialists experienced in leukodystrophies and maintain trial registries. Neuropsychological support and adaptive strategies help optimize function. Work with neurologists experienced in leukodystrophies and pediatric neurodegenerative disease for access to clinical trials.
Meanwhile, 3 Alexander Disease trials are recruiting
Whatever the FDA decides here, research on Alexander Disease does not stop. A few currently enrolling studies, US sites first:
Get notified when new alexander-disease trials open or existing trials change status, add sites, or update eligibility.
Our coverage
Frequently asked questions
When will the FDA decide on Zanvastro?
The FDA has already decided: the application was approved. See the outcome details above.
What is Zanvastro being reviewed for?
Ionis Pharmaceuticals submitted a NDA for Zanvastro in Alexander disease. First and only treatment approved for Alexander disease, cleared ahead of its September 22nd target date. Ionis also received a Rare Pediatric Disease Priority Review Voucher.
What happens after the Zanvastro decision?
If approved, availability is not immediate: specialty pharmacy setup, insurance review, and patient assistance typically take weeks even when everything goes right. If the FDA issues a complete response letter, the application was not approved in its current form; CRLs are often about manufacturing or data presentation rather than efficacy, and sponsors frequently resubmit. This page updates with the outcome either way.
Where this date comes from
The FDA does not publish PDUFA dates; companies disclose them. This one comes from Ionis press release. Dates can move, and the FDA can act early or late. This page rechecks against our calendar, which is re-verified weekly.