Ultragenyx Gets Accelerated FDA Approval for DTX401 Gene Therapy Targeting Rare Metabolic Disorder GSDIa

The U.S. Food and Drug Administration granted accelerated approval to Ultragenyx Pharmaceutical's gene therapy DTX401, known generically as pariglasgene brecaparvovec, for the treatment of Glycogen Storage Disease Type Ia, or GSDIa, a rare metabolic disorder. The decision came just ahead of the PDUFA action date of August 23, 2026, that had been assigned when the FDA accepted the Biologics License Application for Priority Review in February 2026.

GSDIa patients currently rely on demanding dietary management that places a significant burden on individuals and families. The approval sent shares of Ultragenyx, which trades on Nasdaq under the ticker RARE, sharply higher on Wednesday. DTX401 is an AAV8-based gene therapy, and its clearance marks a significant commercial milestone for Ultragenyx as it works to build out a gene therapy portfolio that also includes UX111 for Sanfilippo syndrome Type A, whose own BLA carries a PDUFA date of September 19, 2026.