CARLSBAD, Calif., August 21, 2025 — The U.S. Food and Drug Administration (FDA) has approved DAWNZERA™ (donidalorsen), the first and only RNA-targeted prophylactic therapy for hereditary angioedema (HAE). Approved for adults and adolescents aged 12 years and older, the therapy offers dosing once every 4 or 8 weeks through a subcutaneous autoinjector, representing a new benchmark in rare disease care.
Science Significance
DAWNZERA targets plasma prekallikrein (PKK), a key protein that triggers inflammatory pathways responsible for acute HAE attacks. By silencing this RNA target, the treatment delivers sustained reduction in attack frequency and improved disease control.
The pivotal Phase 3 OASIS-HAE trial showed that DAWNZERA reduced monthly attack rates by 81% compared with placebo over 24 weeks, with efficacy increasing to 87% after the second dose. An open-label extension confirmed long-term control with 94% mean attack reduction after one year.
Regulatory Significance
This approval marks a regulatory milestone as the first FDA-cleared RNA-targeted therapy for HAE, expanding the therapeutic toolkit for a rare genetic disorder with limited treatment options. Acceptance was based on strong safety and efficacy data, supported by long-term extension results and patient-reported outcomes showing preference for this therapy over prior prophylactics
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Business Significance
With HAE affecting an estimated 7,000 people in the U.S., DAWNZERA’s approval positions RNA-based medicines as a commercially viable option for rare disease markets. The extended dosing schedule—every 4 or 8 weeks—reduces treatment burden and enhances patient adherence, strengthening its competitive edge against existing prophylactic options.
Patients’ Significance
For patients, this therapy offers improved quality of life through fewer injections, reduced treatment burden, and strong disease control. In switch studies, patients previously treated with lanadelumab, C1-esterase inhibitors, or berotralstat experienced a 62% further reduction in attack rates after transitioning to DAWNZERA. Additionally, 84% of patients preferred this therapy for convenience, less injection pain, and better outcomes
Policy Significance
This approval highlights the growing policy role of RNA therapeutics in rare disease treatment. It underscores the FDA’s support for innovative modalities addressing high-unmet-need conditions and could shape future guidance on RNA-targeted drug development. The therapy also reflects broader policy efforts to accelerate precision medicine pathways in orphan diseases.
The FDA approval of DAWNZERA marks a transformative step in hereditary angioedema management, introducing the first RNA-based prophylaxis that significantly reduces attack frequency while easing treatment schedules. It reflects the convergence of scientific innovation, regulatory foresight, and patient-centered care, setting the stage for the next generation of RNA therapeutics in rare diseases.
Source: Ionis Pharmaceuticals, Inc. Press Release
