Ultragenyx Secures FDA Acceptance for UX111 BLA With Sept. 19, 2026 PDUFA Date
Ultragenyx’s FDA accepted the resubmitted BLA for UX111 AAV9 gene therapy to treat Sanfilippo syndrome Type A, with a PDUFA action date set for September 19, 2026. The resubmission includes up to eight years of long-term clinical follow-up showing durable improvements versus natural history and acceptable safety.
1. FDA Acceptance and Review Timeline
Ultragenyx announced FDA acceptance of the resubmitted Biologics License Application for UX111, seeking accelerated approval for Sanfilippo syndrome Type A. The agency has set a Prescription Drug User Fee Act action date of September 19, 2026, under a Priority Review granted in February 2025.
2. Long-Term Clinical Data
The BLA resubmission incorporates up to eight years of follow-up data demonstrating clinical improvement over natural history decline and a durable treatment effect across multiple biomarkers. Safety profiles remained acceptable, addressing prior late-cycle review feedback on neurodevelopmental outcomes and biomarker support.
3. Manufacturing and Global Designations
If approved, UX111 will be produced entirely in the U.S. at Andelyn Biosciences in Columbus and Ultragenyx’s Bedford facility. The program has Fast Track, Regenerative Medicine Advanced Therapy, Rare Pediatric Disease and Orphan Drug designations in the U.S., plus PRIME and Orphan medicinal product status in the EU.