---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-337099"
form_type: "8-K"
ticker: "RARE"
cik: "0001515673"
company_name: "Ultragenyx Pharmaceutical Inc."
filed_at: "2025-12-30T23:59:59+00:00"
generated_at: "2026-05-16T11:58:59.574707+00:00"
event_type: "regulatory"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Ultragenyx completes rolling BLA submission for DTX401 gene therapy to FDA for GSDIa

## Summary
- BLA submission for DTX401 (pariglasgene brecaparvovec) completed for glycogen storage disease type Ia; based on 52 treated patients with up to 6 years follow-up.
- Phase 3 GlucoGene study showed significant reductions in daily cornstarch intake while maintaining euglycemia and improved quality of life.
- Rolling review began with non-clinical/clinical modules in August 2025; CMC module now submitted to complete the package.
- DTX401 was well tolerated with an acceptable safety profile per the press release.

## SEC filing metadata
- accession: 0001193125-25-337099
- form_type: 8-K
- ticker: RARE
- cik: 0001515673
- company_name: Ultragenyx Pharmaceutical Inc.
- filed_at: 2025-12-30T23:59:59+00:00
- event_type: regulatory
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1515673/000119312525337099/0001193125-25-337099-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1515673/000119312525337099/rare-20251230.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-337099
- JSON: https://secwatch.observer/filing/0001193125-25-337099.json
- Plain text: https://secwatch.observer/filing/0001193125-25-337099.txt

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