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

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1. 1h ago

   FDA Approves Fayuvi Gene Therapy for Sanfilippo Syndrome

   The Food and Drug Administration approved Ultragenyx Pharmaceutical's gene therapy Fayuvi to treat Sanfilippo syndrome Type A, marking the first-ever treatment for the rare neurodegenerative condition. Following the approval, the company set the price for the gene therapy at $3.95 million. Investor reaction drove Ultragenyx stock up 13 percent. The approval also includes a Priority Review Voucher for the company. This marks a major milestone for patients with the fatal pediatric disorder who previously had no approved treatments available on the market.

   Why it matters

   Sanfilippo syndrome is an ultra-rare, fatal neurodegenerative disease that affects pediatric patients. The approval of Fayuvi expands Ultragenyx's commercial gene therapy portfolio and manufacturing footprint in the United States. High-priced gene therapies continue to draw scrutiny as developers set multi-million-dollar price tags for ultra-rare disease treatments.

   What is confirmed

   • The FDA approved Ultragenyx's gene therapy Fayuvi for Sanfilippo syndrome.
   • Ultragenyx set a $3.95 million price for the rare disease gene therapy.
   • Ultragenyx stock rose 13 percent following the FDA approval.
   • Fayuvi received full U.S. FDA approval in September 2026 as the first-ever treatment for pediatric patients with Sanfilippo syndrome Type A.

   What to watch next

   • Commercial uptake and patient access to the $3.95 million gene therapy
   • Utilization or sale of the Priority Review Voucher awarded to Ultragenyx
   Sources used for this update (6)

   1. statnews.com — FDA approves a new gene therapy for Sanfilippo syndrome, an ultra-rare disease
   2. Fierce Pharma — FDA approves Ultragenyx’s gene therapy Fayuvi for rare neurodegenerative disorder
   3. Yahoo Finance — RARE Stock Up 13% on FDA Approval of Sanfilippo Syndrome Gene Therapy
   4. Reuters — Ultragenyx sets $3.95 million price for rare disease gene therapy
   5. Endpoints News — Updated: Ultragenyx’s new gene therapy will cost $3.95 million
   6. finance.yahoo.com — How Investors Are Reacting To Ultragenyx Pharmaceutical (RARE) First-In-Disease Gene Therapy Approval For FAYUVI
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