STAT+: FDA approves a new gene therapy for Sanfilippo syndrome, an ultra-rare disease

On Thursday, Sept. 17, 2026, the FDA approved a new gene therapy called Fayuvi, developed by Ultragenyx, for Sanfilippo syndrome type A — an ultra-rare disease sometimes known as childhood Alzheimer's. It is the first drug specifically approved to treat Sanfilippo. Ultragenyx did not immediately release a price.

Cara O'Neill, chief science officer of the Cure Sanfilippo Foundation, said in an interview earlier that week that it is hard to overstate what the approval means for everyone living with the horrific disease and watching their children suffer and pass away early. She said it would finally mean that when patients and families receive the shocking diagnosis, they would not be told to take their kids home and love them, but instead would be given hope and an action plan for treatment.