Zilganersen (ION373) was approved by the FDA on September 3, 2026 for Alexander disease, the 37th novel drug approval of 2026 on the FDA's Novel Drug Approvals list.
Verified against: FDA action day September 3, 2026 (NDA 220210 ORIG-1) · Announcement September 3, 2026 (sponsor announcement) · Goal date September 22, 2026 (source not recorded on this row).
Zanvastro (zilganersen) approved as the first treatment for Alexander disease, in pediatric and adult patients (Sep 3 2026).
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.
Primary source: FDA press announcement, September 3, 2026
FDA record of the action: the FDA approved on September 3, 2026, per NDA 220210 ORIG-1 (FDA letter). The sponsor announced it the same day. Action dates on pdufa.bio come from the FDA's own record, not the press release. Every FDA action we hold, by FDA date: FDA approval letters.
| Fund | Shares | Value at quarter end | Filing |
|---|---|---|---|
| Baker Bros. Advisors | 2,047,727 | $162.4 million | filed August 14, 2026 |
| Perceptive Advisors | 566,000 | $44.9 million | filed August 14, 2026 |
13F reports list long positions in common stock at quarter end, are due 45 days later, and show no short positions or later trades. Notes, warrants and other instruments are not counted as shares.
Yes. The FDA approved the application for Zanvastro (zilganersen) on September 3, 2026, per the FDA's own record. The primary source is linked on this page.
Zanvastro (zilganersen) is an Ionis Pharmaceuticals, Inc. (IONS) program. The FDA decision came on September 3, 2026; the FDA's own record of the decision is linked on this page.
Measured over the 120 trading days before the decision (T-120 to T-1), IONS moved -13.9%. That is the recorded price path into this specific event. Historical measurement, not a prediction, and not investment advice.