Ultragenyx’s MPS IIIA Gene Therapy Application Validated by EMA

On October 2, 2026, Ultragenyx announced that the European Medicines Agency (EMA) had validated its marketing authorisation application for rebisufligene etisparvovec (UX111), an investigational gene therapy for mucopolysaccharidosis type IIIA (MPS IIIA), also known as Sanfilippo syndrome type A.

EMA validation means the application is sufficiently complete to begin formal scientific review. It is not marketing approval and does not establish the therapy’s safety or efficacy.

The proposed treatment is a single-dose intravenous AAV9 gene therapy designed to deliver a functional copy of the SGSH gene, which is deficient in people with MPS IIIA.

The therapy has received EMA PRIME and Orphan Drug designations. The application is also expected to fall under the EU’s Joint Clinical Assessment framework.