Ultragenyx Resubmits BLA for UX111 Gene Therapy with New Long-Term Data for Sanfilippo Syndrome Type A
Ultragenyx resubmitted its Biologics License Application (BLA) to the FDA for UX111, an AAV9 gene therapy for Sanfilippo syndrome type A (MPS IIIA), including long-term clinical data on neurologic, biomarker, and safety improvements.12345
The resubmission addresses a Complete Response Letter from July 2025 related to manufacturing (CMC) observations and adds durable biomarker reductions, such as CSF heparan sulfate, with favorable safety profile.245
FDA's six-month priority review has begun; PDUFA action date expected in Q3 2026.245
If approved, UX111 would be the first therapy for this fatal pediatric neurodegenerative disorder.1345
New long-term data announced February 3, 2026, shows substantial biomarker improvements and functional benefits vs. natural history, consistent across age and severity.2
Sources:
1. https://simplywall.st/stocks/us/pharmaceuticals-biotech/nasdaq-rare/ultragenyx-pharmaceutical/news/ultragenyx-bla-resubmission-puts-ux111-and-rare-valuation-in/amp
2. https://curesanfilippofoundation.org/2026/01/ultragenyx-resubmits-ux111-to-fda-for-accelerated-approval-of-sanfilippo-type-a/
3. https://simplywall.st/stocks/us/pharmaceuticals-biotech/nasdaq-rare/ultragenyx-pharmaceutical/news/how-ultragenyxs-resubmitted-ux111-gene-therapy-application-c
4. https://www.stocktitan.net/sec-filings/RARE/8-k-ultragenyx-pharmaceutical-inc-reports-material-event-6355e02fde79.html