DTX401 AAV gene therapy (pariglasgene brecaparvovec) was approved by the FDA on August 19, 2026 for glycogen Storage Disease Type Ia (GSDIa).
GENGLYCOS (pariglasgene brecaparvovec-opnr), an AAV8 gene therapy for glycogen storage disease type Ia, granted accelerated approval on August 19, 2026 - four days ahead of its August 23 PDUFA goal date.
The PDUFA target action date was August 23, 2026; the FDA granted accelerated approval on August 19 and Ultragenyx announced it after the market close that day. GENGLYCOS is the first FDA-approved treatment designed to treat the underlying cause of GSDIa, and Ultragenyx's first approved gene therapy. It is a single intravenous AAV8 gene therapy delivering G6Pase expression under the native promoter; patients in clinical studies reduced their reliance on round-the-clock cornstarch dosing. As a condition of accelerated approval, Ultragenyx will provide two years of safety and efficacy data from open-label commercial treatment of 50 patients and 20 control patients. The BLA held Priority Review, and the approval earned Ultragenyx a rare pediatric disease 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: Ultragenyx press release, August 19, 2026
FDA record of the action: the FDA approved on August 19, 2026, per CBER approval letter (GENGLYCOS) (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 |
|---|---|---|---|
| RTW Investments | 7,796,895 | $260.3 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 GENGLYCOS (pariglasgene brecaparvovec-opnr, DTX401) on August 19, 2026, per the FDA's own record. The primary source is linked on this page.
GENGLYCOS (pariglasgene brecaparvovec-opnr, DTX401) is an Ultragenyx Pharmaceutical Inc. (RARE) program. The FDA decision came on August 19, 2026; the company's own announcement is linked on this page.
Measured over the 120 trading days before the decision (T-120 to T-1), RARE moved +10.6%. That is the recorded price path into this specific event. Historical measurement, not a prediction, and not investment advice.