---
schema_version: "secwatch.filing_event.v1"
accession: "0001140361-25-032176"
form_type: "8-K"
ticker: "IONS"
cik: "0000874015"
company_name: "IONIS PHARMACEUTICALS INC"
filed_at: "2025-08-21T23:59:59+00:00"
generated_at: "2026-05-17T11:00:42.283685+00:00"
event_type: "regulatory"
sentiment: "positive"
materiality_score: 0.9
calibrated_materiality_score: 0.9
confidence: "high"
source: SEC EDGAR
---

# FDA approves Ionis' DAWNZERA (donidalorsen) for HAE prophylaxis in patients 12+

## Summary
- First and only RNA-targeted HAE medicine; self-administered every 4 or 8 weeks via autoinjector.
- Phase 3 OASIS-HAE: Q4W reduced monthly attack rate 81% vs placebo (primary endpoint); 87% from second dose.
- OASISplus OLE: 94% attack rate reduction after one year; switch cohort reduced attacks 62% vs prior therapy.
- Ionis' second independent launch in nine months; 84% of patients surveyed preferred DAWNZERA over prior treatment.

## SEC filing metadata
- accession: 0001140361-25-032176
- form_type: 8-K
- ticker: IONS
- cik: 0000874015
- company_name: IONIS PHARMACEUTICALS INC
- filed_at: 2025-08-21T23:59:59+00:00
- event_type: regulatory
- sentiment: positive
- materiality_score: 0.9
- calibrated_materiality_score: 0.9
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/874015/000114036125032176/0001140361-25-032176-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/874015/000114036125032176/ef20054334_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001140361-25-032176
- JSON: https://secwatch.observer/filing/0001140361-25-032176.json
- Plain text: https://secwatch.observer/filing/0001140361-25-032176.txt

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