What Was Approved?
On August 21, 2025, the U.S. Food and Drug Administration approved Dawnzera (donidalorsen) to prevent attacks of hereditary angioedema, or HAE, in adults and pediatric patients 12 years of age and older.
Dawnzera is a preventive treatment and is not intended to treat an acute HAE attack once it has started.
How Does Dawnzera Work?
Dawnzera is a prekallikrein-directed antisense oligonucleotide.
It reduces production of prekallikrein, a protein involved in the pathway that contributes to swelling attacks in HAE.
How Is Dawnzera Given?
The recommended dose is:
80 mg by subcutaneous injection every 4 weeks.
For some patients, 80 mg every 8 weeks may be considered.
The product may be self-administered after appropriate training.
What Did the Clinical Trial Show?
The OASIS-HAE trial included 90 patients age 12 and older.
Compared with placebo, Dawnzera reduced the rate of investigator-confirmed HAE attacks by approximately:
- 81% with dosing every 4 weeks
- 55% with dosing every 8 weeks
These are average study results and do not predict the response of an individual patient.
What Is an Important Safety Concern?
Serious hypersensitivity reactions, including anaphylaxis, have been reported.
Dawnzera is contraindicated in patients with a history of serious hypersensitivity to donidalorsen or its ingredients.
Bottom Line
Dawnzera (donidalorsen) is an FDA-approved preventive treatment for HAE attacks in patients age 12 and older.
It is administered every four weeks, with an every-eight-week option for selected patients, and it should not be confused with medication used to treat an acute HAE attack.
Sources
- U.S. Food and Drug Administration (FDA) — Drug Trials Snapshot: Dawnzera.
- U.S. Food and Drug Administration (FDA) — Dawnzera Prescribing Information, August 2025.