Ultragenyx disclosed new clinical data from its resubmitted gene therapy for Sanfilippo syndrome type A aimed at convincing the FDA to grant approval. The company reported cognition-related measures from 17 treated patients as part of the resubmission package and framed the dataset as addressing prior regulatory concerns. Ultragenyx’s filing and accompanying data release represent a critical regulatory inflection: the firm is attempting to convert additional clinical signals into an approvable benefit-risk profile for a devastating pediatric neurodegenerative disorder. FDA response to the resubmission will determine whether this gene therapy advances toward commercialization or requires further evidence.