The FDA granted accelerated approval to Ultragenyx’s one-time gene therapy Genglycos (pariglasgene brecaparvovec; DTX-401) for glycogen storage disease type Ia (GSDIa), marking the company’s first approved gene therapy and expanding its roster to five marketed treatments. The therapy is designed to deliver a functional gene to the liver to restore glucose regulation in patients with an enzyme deficiency that can drive life-threatening metabolic crises. Ultragenyx said it expects therapy availability within 30 to 60 days at specialized treatment centers and set a per-patient wholesale acquisition cost of $2.7 million. The approval also comes with a priority review voucher, which Ultragenyx plans to sell, supporting the company’s stated path toward profitability. The decision adds to a rare-disease pipeline increasingly shaped by platform-led vector engineering and monetization mechanics such as priority review vouchers. For investors and development teams, it underscores how FDA accelerated pathways can rapidly translate late-stage gene therapy results into market access for very small patient populations. Clinically, the approval also sets the stage for follow-on regulatory catalysts: Ultragenyx continues to position UX111 and GTX-102 for additional FDA decisions tied to other ultra-rare indications and earlier review timelines.