Ionis Pharmaceuticals, Inc. received FDA approval on August 21, 2025, for DAWNZERA™ (donidalorsen), the first RNA-targeted therapy for prophylaxis against hereditary angioedema (HAE) attacks in adults and pediatric patients aged 12 and older. HAE, a rare genetic condition affecting approximately 7,000 Americans, causes recurrent, potentially life-threatening swelling in various body parts. DAWNZERA targets plasma prekallikrein (PKK), a key protein in HAE attack pathways, and is administered via subcutaneous autoinjector every four (Q4W) or eight weeks (Q8W), offering the longest dosing interval among HAE prophylactics. This approval marks Ionis’ second independent product launch within nine months, following TRYNGOLZA® for familial chylomicronemia syndrome.
The approval is based on robust data from the Phase 3 OASIS-HAE study, which demonstrated an 81% reduction in monthly HAE attack rates with DAWNZERA Q4W compared to placebo over 24 weeks, increasing to 87% from the second dose. The study also showed a ~90% reduction in moderate-to-severe attacks. The ongoing OASISplus open-label extension study further confirmed DAWNZERA’s efficacy, with a 94% mean attack rate reduction after one year for both Q4W and Q8W dosing, highlighting sustained disease control and reduced treatment burden.
Additional OASISplus data from a switch cohort showed that patients transitioning from other prophylactics (lanadelumab, C1-esterase inhibitor, or berotralstat) to DAWNZERA Q4W experienced a 62% reduction in HAE attack rates over 16 weeks, with 84% preferring DAWNZERA for better disease control and ease of administration. The drug’s safety profile is favorable, with common adverse reactions including injection site reactions, upper respiratory infections, urinary tract infections, and abdominal discomfort. Hypersensitivity reactions, including anaphylaxis, are a noted risk, requiring discontinuation and appropriate management if they occur.
Ionis is supporting HAE patients through its Ionis Every Step™ program, offering resources like insurance assistance, patient education, and affordability programs. DAWNZERA will be available in the U.S. soon, with a webcast held on August 21, 2025, to discuss the approval. This milestone underscores Ionis’ commitment to advancing RNA-targeted therapies for rare diseases.
