Ultragenyx Announces New Data Demonstrating that Treatment with UX111 AAV Gene Therapy Significantly Improved Clinical Function Across Multiple Developmental Domains in Children with Sanfilippo Syndrome Type A (MPS IIIA) Correlated with Sustained Reductio

Modified intent-to-treat group demonstrated +22.7 point (p<0.0001) treatment effect in the mean Bayley-III cognitive raw score compared to natural history data (ages 24-60 months)