Ultragenyx UX111 AAV9 Gene Therapy for Sanfilippo Syndrome Type A PDUFA Date September 19, 2026
Ultragenyx Pharmaceutical (NASDAQ: RARE) awaits its September 19, 2026 PDUFA target action date for UX111 (rebisufligene etisparvovec, an AAV9 gene therapy delivering the SGSH gene) for the treatment of Sanfilippo syndrome type A (mucopolysaccharidosis type IIIA, MPS IIIA, a rare autosomal recessive lysosomal storage disorder caused by SGSH gene mutations that results in progressive cognitive decline in early childhood and death typically by the second decade). If approved, UX111 would become the first FDA-approved therapy for MPS IIIA, where the current standard of care remains supportive symptom management. The AAV9-based intravenous delivery approach mirrors the Novartis Zolgensma (onasemnogene abeparvovec) commercial template for spinal muscular atrophy and continues the neurometabolic gene therapy pipeline. Not a peptide, but the approval would extend the AAV gene therapy commercial category that has continued to reshape the rare-disease landscape alongside enzyme replacement therapies and the emerging small-molecule chaperone class.