---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-094806"
form_type: "8-K"
ticker: "RARE"
cik: "0001515673"
company_name: "Ultragenyx Pharmaceutical Inc."
filed_at: "2025-07-09T23:59:59+00:00"
generated_at: "2026-05-18T08:52:12.810315+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Ultragenyx's UX143 Phase 3 Orbit passes DMC safety review; final analysis year-end 2025

## Summary
- DMC confirms acceptable safety profile for UX143 in pediatric/young adult OI patients; study continues to final analysis.
- Final analysis of Phase 3 Orbit trial expected around end of 2025, with statistical threshold p<0.04.
- Safety in younger patients consistent with prior studies; no data from Cosmic study analyzed at interim.
- Patients continue dosing; final analyses after at least 18 months therapy.

## SEC filing metadata
- accession: 0000950170-25-094806
- form_type: 8-K
- ticker: RARE
- cik: 0001515673
- company_name: Ultragenyx Pharmaceutical Inc.
- filed_at: 2025-07-09T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1515673/000095017025094806/0000950170-25-094806-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1515673/000095017025094806/rare-20250709.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-094806
- JSON: https://secwatch.observer/filing/0000950170-25-094806.json
- Plain text: https://secwatch.observer/filing/0000950170-25-094806.txt

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