FDA Approves First Sanfilippo Gene Therapy From Ultragenyx

Ultragenyx Pharmaceutical won FDA approval for Fayuvi, the first treatment addressing the root cause of Sanfilippo syndrome type A, an ultra-rare inherited neurological disorder, according to MedCity News.

Sanfilippo syndrome type A, also known as MPS IIIA, stems from a genetic defect that prevents the body from breaking down certain sugar molecules. The buildup damages the central nervous system, leading to progressive cognitive and neurological decline in children. Until now, there was no approved therapy targeting that underlying mechanism. Fayuvi is a gene therapy designed to correct the defect rather than manage symptoms.

The approval is Ultragenyx's second for a gene therapy, cementing the company's position as a specialist in rare disease medicines. For a patient population with no prior options, the decision is a meaningful milestone. It also adds to the growing roster of FDA-cleared gene therapies, a category that continues to expand despite ongoing questions about pricing, access, and long-term durability of one-time treatments.