secwatch.observer — SEC 8-K summary
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Issuer:     Ultragenyx Pharmaceutical Inc. (RARE)
CIK:        0001515673
Form:       8-K
Filed at:   2026-02-03T23:59:59+00:00
Accession:  0001193125-26-034474
Event type: other_material
Sentiment:  positive
Materiality: 0.85
Item codes: 8.01
LLM model:  deepseek-v4-flash:cloud@v2

Ultragenyx UX111 gene therapy shows significant cognitive benefit in MPS IIIA; BLA resubmitted with PDUFA Q3 2026
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- Children under 2 treated with UX111 showed +23.2 point improvement in Bayley-III cognitive raw score vs natural history (p<0.0001).
- 81.5% of overall efficacy set achieved ≥50% reduction in CSF heparan sulfate; median reduction 63.98% (p<0.001).
- Functional retention observed: all older children retained communication; 9/10 retained ambulation and self-feeding.
- UX111 well-tolerated with median follow-up 4.8 years; no TMA, myocarditis, DRG toxicity, or malignancy.
- BLA resubmitted to FDA seeking accelerated approval; PDUFA date expected in Q3 2026.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1515673/000119312526034474/0001193125-26-034474-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1515673/000119312526034474/rare-20260203.htm
  HTML page:      https://secwatch.observer/filing/0001193125-26-034474

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