---
schema_version: "secwatch.filing_event.v1"
accession: "0001515673-26-000006"
form_type: "8-K"
ticker: "RARE"
cik: "0001515673"
company_name: "Ultragenyx Pharmaceutical Inc."
filed_at: "2026-09-17T19:55:37+00:00"
generated_at: "2026-09-17T19:57:24.087996+00:00"
event_type: "regulatory"
sentiment: "positive"
materiality_score: 0.8
calibrated_materiality_score: 0.8
confidence: "high"
source: SEC EDGAR
---

# Ultragenyx gets FDA standard full approval for FAYUVI, first Sanfilippo type A treatment

## Summary
- FDA granted standard full approval of FAYUVI (UX111) for pediatric MPS IIIA (Sanfilippo syndrome type A) on Sept 17, 2026.
- FAYUVI is the first-ever FDA-approved treatment for Sanfilippo syndrome type A, a progressive fatal neurodegenerative disease.
- This is Ultragenyx's second gene therapy approval; company received a Priority Review Voucher upon approval.
- Approval covers pediatric patients with mucopolysaccharidosis type IIIA; trade name rebisufligene etisparvovec-hopf.

## SEC filing metadata
- accession: 0001515673-26-000006
- form_type: 8-K
- ticker: RARE
- cik: 0001515673
- company_name: Ultragenyx Pharmaceutical Inc.
- filed_at: 2026-09-17T19:55:37+00:00
- event_type: regulatory
- sentiment: positive
- materiality_score: 0.8
- calibrated_materiality_score: 0.8
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1515673/000151567326000006/0001515673-26-000006-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1515673/000151567326000006/rare-20260917.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001515673-26-000006
- JSON: https://secwatch.observer/filing/0001515673-26-000006.json
- Plain text: https://secwatch.observer/filing/0001515673-26-000006.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.