# FDA approval of Genglycos for GSDIa

> Live situation record from CLSTR: https://clstr.news/situations/fda-approval-of-genglycos-for-gsdia
> Updated: 2026-08-26T17:55:01.000Z. Sources: 8. Developments: 2.

The U.S. Food and Drug Administration (FDA) has granted accelerated approval to Ultragenyx Pharmaceutical’s gene therapy, Genglycos (pariglasgene brecaparvovec-opnr). This is the first authorized gene therapy for adult and pediatric patients aged eight years and older suffering from glycogen storage disease type Ia (GSDIa).

GSDIa is a rare genetic metabolic disorder caused by a deficiency in the glucose-6-phosphatase enzyme, which prevents the liver from releasing glucose into the bloodstream. Management of the condition typically requires frequent intake of raw cornstarch to maintain glucose levels. Genglycos utilizes an adeno-associated virus serotype 8 (AAV8) vector to deliver a functional copy of the G6PC gene to liver cells.

The therapy is intended to reduce, rather than entirely replace, the daily requirement for cornstarch supplementation. Clinical data from a Phase III trial indicated that the treatment reduced daily cornstarch consumption by 31%. To maintain its approval, Ultragenyx is required to provide ongoing efficacy and safety data.

## Timeline

### 2026-08-26: FDA approves Genglycos for glycogen storage disease type Ia

The FDA has granted accelerated approval to Genglycos, the first gene therapy for adults and children with glycogen storage disease type Ia.

2 sources. https://clstr.news/cluster/fda-approves-genglycos-for-glycogen-storage-disease-type-ia

### 2026-08-19: Ultragenyx's Genglycos receives FDA accelerated approval for GSDIa

The FDA has granted accelerated approval to Ultragenyx Pharmaceutical’s Genglycos, the first gene therapy targeting the underlying cause of glycogen storage disease type Ia (GSDIa).

6 sources. https://clstr.news/cluster/ultragenyxs-genglycos-receives-fda-accelerated-approval-for-gsdia

---
Cite as: FDA approval of Genglycos for GSDIa. CLSTR, https://clstr.news/situations/fda-approval-of-genglycos-for-gsdia