Ultragenyx said the European Medicines Agency (EMA), the European Union medicines regulator, has validated its Marketing Authorisation Application for rebisufligene etisparvovec, an investigational gene therapy for mucopolysaccharidosis type IIIA (MPS IIIA), also known as Sanfilippo syndrome Type A. Validation confirms that the application is sufficiently complete for formal scientific review, but does not constitute approval or establish the therapy’s safety or efficacy. The therapy has also received PRIME and Orphan Drug Designations from the EMA. Ultragenyx said it is continuing regulatory discussions in multiple regions, including with the UK’s Medicines and Healthcare products Regulatory Agency and the Saudi Food and Drug Authority, while the application will be assessed under the European Union’s Joint Clinical Assessment framework. MPS IIIA is an ultra-rare, fatal lysosomal storage disease that causes progressive neurological deterioration in early childhood. Ultragenyx said the therapy received FDA approval on September 17, 2026.