Ultragenyx Advances Gene Therapy for Glycogen Storage Disease Type Ia Following Phase 3 Success

1. Positive Phase 3 Results: Ultragenyx announced positive top-line results from its Phase 3 GlucoGene study of DTX401, an investigational gene therapy for glycogen storage disease type Ia (GSDIa) patients aged eight years and older.
2. Primary Endpoint Met: The study met its primary endpoint, demonstrating a statistically significant and clinically meaningful reduction in daily cornstarch intake compared to placebo at Week 48.
3. Safety Profile: DTX401 showed an acceptable and expected safety profile, consistent with Phase 1/2 study results, with manageable vector-induced hepatic effects and no AAV8 class effects of dorsal root ganglion toxicity or thrombotic microangiopathy observed through Week 48.
4. Long-term Efficacy: Long-term Phase 1/2 data presented at the American Society of Gene and Cell Therapy 2024 demonstrated durable response, with sustained, clinically meaningful reductions in cornstarch lasting up to 5 years in patients treated with open-label DTX401.
5. Regulatory Plans: Ultragenyx will present full 48-week data from the Phase 3 study at a scientific conference later this year and will discuss these results with regulatory authorities to support a marketing application in 2025.
6. Impact on Patients: The treatment offers meaningful benefits to patients, improving their quality of life by reducing the need for constant attention to manage blood sugar levels and preventing severe low blood sugar and acidosis.