Zanvastro (zilganersen) approved as the first treatment for Alexander disease, in pediatric and adult patients (Sep 3 2026).
Run-up into the decision (T-120 → T+5)
Daily close, T-120 (3/13/26) through T+1. Run-up high $86.33 on 7/7/26, low $51.77 on 7/31/26 (T-120 to T-1). FDA decision 9/3/26. Historical price action, not a forecast.
Key facts
FDA decision date2026-09-03
OutcomeApproved
Drug / candidateZanvastro (zilganersen)
IndicationAlexander disease in pediatric and adult patients
CompanyIonis Pharmaceuticals, Inc.
Market-cap tierMid
120-day run-up (T-120→T-1)-13.9%
Cohort decision-day move (history)2.2% median (n=232)
The PDUFA goal date was September 22, 2026. The FDA approved on September 3, 2026, 19 days early. Zanvastro is an antisense oligonucleotide given by intrathecal injection every three months, and the first FDA-approved treatment for Alexander disease. The application carried Orphan Drug, Fast Track, Breakthrough Therapy and Rare Pediatric Disease designations, the last conferring a priority review voucher.
Run-up figures are the stock's own daily closing path over the 120 trading days before the decision, from our price history. Cohort move is the historical median absolute decision-day move for this market-cap tier. History, not a prediction.
Not affiliated with or endorsed by the FDA. pdufa.bio is an independent publication with no affiliation with, endorsement by, sponsorship by, or connection to the U.S. Food and Drug Administration or any other government agency. “FDA”, “PDUFA” and all company, drug and ticker names are used descriptively and remain the property of their respective owners.
Informational and educational purposes only. Not investment advice. Nothing on this page is investment, legal, tax or medical advice, or an offer or solicitation to buy or sell any security. pdufa.bio is not a registered investment adviser or broker-dealer and does not recommend trades or publish individual-drug approval probabilities. Verify every date and outcome against primary FDA, SEC or company filings. Data is provided as is, without warranty of any kind, and past behaviour does not predict future outcomes.