---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-030590"
form_type: "8-K"
ticker: "RARE"
cik: "0001515673"
company_name: "Ultragenyx Pharmaceutical Inc."
filed_at: "2026-01-30T23:59:59+00:00"
generated_at: "2026-05-16T05:57:41.719383+00:00"
event_type: "regulatory"
sentiment: "positive"
materiality_score: 0.8
calibrated_materiality_score: 0.8
confidence: "high"
source: SEC EDGAR
---

# Ultragenyx resubmits UX111 BLA for Sanfilippo type A to FDA; PDUFA expected Q3 2026

## Summary
- Resubmitted BLA for UX111 gene therapy for Sanfilippo type A on Jan 30, 2026.
- Submission addresses CMC observations from July 2025 CRL and includes additional year of clinical follow-up data.
- FDA previously acknowledged robust neurodevelopmental data; updated data show durable treatment effect and acceptable safety.
- PDUFA action date expected within a month; six-month review period suggests PDUFA in Q3 2026.
- If approved, UX111 would be the first approved therapy for Sanfilippo syndrome type A.

## SEC filing metadata
- accession: 0001193125-26-030590
- form_type: 8-K
- ticker: RARE
- cik: 0001515673
- company_name: Ultragenyx Pharmaceutical Inc.
- filed_at: 2026-01-30T23:59:59+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/1515673/000119312526030590/0001193125-26-030590-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1515673/000119312526030590/rare-20260130.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-030590
- JSON: https://secwatch.observer/filing/0001193125-26-030590.json
- Plain text: https://secwatch.observer/filing/0001193125-26-030590.txt

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