---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-257538"
form_type: "8-K"
ticker: "RARE"
cik: "0001515673"
company_name: "Ultragenyx Pharmaceutical Inc."
filed_at: "2025-10-30T23:59:59+00:00"
generated_at: "2026-05-17T01:19:12.450374+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Ultragenyx doses first patient in Aurora study of GTX-102 for Angelman; Aspire Phase 3 fully enrolled

## Summary
- First patient dosed in global Aurora study (NCT07157254) evaluating GTX-102 (apazunersen) for Angelman syndrome across all genotypes and ages 1 to <65.
- Aurora will enroll ~60 participants in four cohorts based on age and genotype; primary endpoints include Bayley-4 and MDRI.
- Phase 3 Aspire study fully enrolled with 129 participants (ages 4-17, UBE3A deletion), data expected H2 2026.
- Aurora expands patient population beyond deletion-type to include UPD, ICD, and mutation genotypes.
- Cohorts A, B, C single-arm; Cohort D randomized 2:1 GTX-102 vs no treatment with crossover at Week 24.

## SEC filing metadata
- accession: 0001193125-25-257538
- form_type: 8-K
- ticker: RARE
- cik: 0001515673
- company_name: Ultragenyx Pharmaceutical Inc.
- filed_at: 2025-10-30T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1515673/000119312525257538/0001193125-25-257538-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1515673/000119312525257538/rare-20251030.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-257538
- JSON: https://secwatch.observer/filing/0001193125-25-257538.json
- Plain text: https://secwatch.observer/filing/0001193125-25-257538.txt

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