Ultragenyx said on Sept. 17, 2026, that the FDA granted full approval to FAYUVI (rebisufligene etisparvovec-hopf), also known as UX111, for pediatric patients with Sanfilippo syndrome type A, or MPS IIIA.
FAYUVI is the first FDA-approved treatment specifically for Sanfilippo type A, a rare, progressive and often fatal neurodegenerative disease affecting the brain and nervous system.
The AAV9-based gene therapy is indicated for neurologic manifestations in children with preserved neurodevelopmental function.
The FDA granted standard approval rather than the accelerated approval Ultragenyx had initially sought. The company also received a Priority Review Voucher.
Ultragenyx expects FAYUVI to become available through qualified U.S. treatment centers within 30 to 60 days. Its reported U.S. list price is $3.95 million for the one-time treatment.
The approval follows a 2025 FDA complete-response letter related to chemistry, manufacturing and controls issues; Ultragenyx later resubmitted the application.
This is Ultragenyx’s second gene-therapy approval and sixth overall FDA approval.
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