secwatch.observer — SEC 8-K summary
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Issuer:     Ultragenyx Pharmaceutical Inc. (RARE)
CIK:        0001515673
Form:       8-K
Filed at:   2024-04-15T23:59:59+00:00
Accession:  0000950123-24-003302
Event type: other_material
Sentiment:  positive
Materiality: 0.85
Item codes: 8.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

Ultragenyx reports positive Phase 1/2 GTX-102 data in Angelman syndrome with rapid, sustained improvements
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- Expansion Cohorts A&B (24 patients) at Day 170 showed clinically meaningful improvements across cognition, behavior, sleep, motor, and communication domains vs natural history.
- Multi-domain responder index (MDRI) net response of +2.0 (p<0.0001) at Day 170; majority of patients achieved +2 to +4 domain improvement.
- Dose-escalation Cohorts 4-7 (15 patients) at Day 758 showed sustained long-term benefit; MDRI net response +2.0 (p=0.0007) at Day 338.
- No unexpected serious adverse events; three patients had mild-moderate lower extremity weakness (resolved, no recurrence on re-dosing).
- FDA notified of safety events; no issues raised or additional actions required; data to be presented at AAN 2024.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1515673/000095012324003302/0000950123-24-003302-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1515673/000095012324003302/rare-20240415.htm
  HTML page:      https://secwatch.observer/filing/0000950123-24-003302

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