secwatch.observer — SEC 8-K summary
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Issuer:     Ultragenyx Pharmaceutical Inc. (RARE)
CIK:        0001515673
Form:       8-K
Filed at:   2025-10-30T23:59:59+00:00
Accession:  0001193125-25-257538
Event type: other_material
Sentiment:  neutral
Materiality: 0.65
Item codes: 8.01
LLM model:  deepseek-v4-flash:cloud@v2

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

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1515673/000119312525257538/0001193125-25-257538-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1515673/000119312525257538/rare-20251030.htm
  HTML page:      https://secwatch.observer/filing/0001193125-25-257538

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer