Zanvastro (zilganersen) for Alexander disease
What the FDA decided
The FDA approved Ionis Pharmaceuticals's NDA 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
Read our full Alexander Disease treatment summary
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.
The Alexander Disease page has every treatment and trial →Meanwhile, 2 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:
You'll hear about future FDA decisions and new recruiting trials for Alexander Disease. Unsubscribe anytime.
Our coverage
Frequently asked questions
Has the FDA decided on Zanvastro?
The FDA has already decided. It approved the application.
Details: the outcome and what it means are at the top of this page.
Source: Ionis press release
What was Zanvastro approved for?
The FDA approved Ionis Pharmaceuticals's NDA for Zanvastro in Alexander disease.
What to know: 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.
How it works: Antisense oligonucleotide that reduces GFAP protein production.
More: the Zanvastro drug page explains it in plain language.
Is there already an FDA-approved treatment for Alexander Disease?
Yes. Trial Friend's drug list includes 1 FDA-approved drug for Alexander Disease.
Approved: Zanvastro (zilganersen).
Check: the Alexander Disease page also searches FDA drug labels for approved treatments.
What did the Zanvastro trials show?
The FDA approved Zanvastro on September 3, 2026. The pivotal study (NCT04849741) ran at 13 sites in 8 countries.
More: the Zanvastro drug page has the full trial history and sources.
What are the side effects of Zanvastro?
The most common side effects (in more than 25% of patients) were vomiting, back pain, cough, headache, and headache after the spinal injection. Some patients developed aseptic meningitis, which is irritation of the lining around the brain and spinal cord.
More: the Zanvastro drug page lists the warnings in full.
How much will Zanvastro cost?
Trial Friend does not list a price for Zanvastro. What you pay depends on your insurance and on help from the drugmaker or a charity fund.
Drugmaker help: Ionis Every Step.
Find help: the patient assistance finder lists programs by insurance type.
What happens after the Zanvastro decision?
The FDA approved Zanvastro for Alexander disease on September 3, 2026.
Next steps: getting the drug still takes time. Specialty pharmacy setup, insurance review and patient assistance often take weeks. Our guide covers what families can do on day 1.
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 daily.