---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-24-084254"
form_type: "8-K"
ticker: "RARE"
cik: "0001515673"
company_name: "Ultragenyx Pharmaceutical Inc."
filed_at: "2024-07-17T23:59:59+00:00"
generated_at: "2026-05-31T20:12:05.592748+00:00"
event_type: "regulatory"
sentiment: "positive"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Ultragenyx aligns with FDA on Phase 3 design for GTX-102 in Angelman syndrome

## Summary
- FDA alignment on EoP2 meeting for GTX-102; Phase 3 trial to enroll ~120 UBE3A deletion patients.
- Primary endpoint: Bayley-4 cognitive raw score; 48-week double-blind, sham-controlled design.
- Patients in control arm eligible to roll over to treatment after double-blind period.
- EMA accepted Phase 3 design under PRIME; PMDA meeting expected in coming weeks.
- Plans for open-label study to evaluate GTX-102 in other Angelman genotypes and age groups.

## SEC filing metadata
- accession: 0000950170-24-084254
- form_type: 8-K
- ticker: RARE
- cik: 0001515673
- company_name: Ultragenyx Pharmaceutical Inc.
- filed_at: 2024-07-17T23:59:59+00:00
- event_type: regulatory
- sentiment: positive
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1515673/000095017024084254/0000950170-24-084254-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1515673/000095017024084254/rare-20240717.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-24-084254
- JSON: https://secwatch.observer/filing/0000950170-24-084254.json
- Plain text: https://secwatch.observer/filing/0000950170-24-084254.txt

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