Dawnzera (donidalorsen) granted European Union marketing authorisation for the prevention of hereditary angioedema
January 21, 2026 – Biotechnology, Clinical Trials, Drug Discovery, Other, Pharmaceutical – European Commission, Ionis Pharmaceuticals, Otsuka Pharmaceutical Europe, clinical trials, hereditary angioedema, marketing authorisation
- Donidalorsen is a first-in-class RNA-targeted prophylactic therapy for patients with hereditary angioedema (HAE)
- Donidalorsen demonstrated a significant reduction in HAE attack rate compared with placebo in the Phase 3 OASIS-HAE study
- HAE is a rare and potentially life-threatening genetic condition affecting approximately 15,000 people in Europe.
21 January 2026 — Windsor, UK — Otsuka Pharmaceutical Europe Ltd today announces that the European Commission (EC) has granted marketing authorisation for Dawnzera (donidalorsen) for the routine prevention of recurrent attacks of hereditary angioedema (HAE) in adults and adolescents aged 12 years and older.
HAE is a genetic condition which causes unpredictable swelling episodes that can affect the extremities, face, abdomen, genitals and the larynx. Approximately 50% of people with HAE experience their first symptoms by the age of 10 with the majority experiencing symptoms or their first attack by 18 years of age. Anxiety and depression are common in patients with HAE, often stemming from the unpredictable nature, frequency, and severity of swelling episodes.
“As the first European-approved RNA-targeted therapy for HAE, donidalorsen represents a welcome development in therapeutic options for preventing attacks,” said Henrik Balle Boysen, President, HAE International (HAEi), the global network of HAE patient organisations. “Today’s approval gives people living with HAE and their physicians another choice for aligning treatment with individual needs.”
The pivotal, double-blind, placebo-controlled, Phase 3 OASIS-HAE study (n=90) showed the use of donidalorsen 80mg every four weeks (Q4W) led to an 81% reduction in 4-weekly HAE attack rate compared to placebo (mean attack rates 0.44 vs. 2.26 respectively) over 24 weeks, meeting the study’s primary endpoint. A 55% reduction (mean attack rate 1.02) compared to placebo was observed with dosing every eight weeks (Q8W).
At week 24, 91% of donidalorsen Q4W patients had well-controlled disease compared to 41% of patients in the placebo group, as measured by the Angioedema Control Test, and improvements in quality of life were observed, demonstrated by a reduction from baseline of 24.8 points in mean Angioedema Quality-of-Life total score.
No major safety concerns were identified in the study, with similar Q4W and Q8W dosing adverse event profiles. The most common adverse events with donidalorsen include injection site reactions, increased hepatic enzymes and hypersensitivity (including anaphylaxis).
“The European Commission’s authorisation of donidalorsen is a welcome decision for the HAE clinical community,” said Prof. Danny Cohn, Internist, Department of Vascular Medicine, Amsterdam University Medical Center. “With encouraging trial results donidalorsen has demonstrated clinical efficacy and offers a beneficial addition to our current treatment options.”
Ionis Pharmaceuticals, Inc. and Otsuka Pharmaceutical Co., Ltd entered the initial license agreement for the commercialisation of donidalorsen in Europe in 2023, with the agreement later broadening to Asia Pacific. Ionis has maintained the clinical development of donidalorsen as well as the responsibility for its launch in the United States with Otsuka utilising its expertise in rare disease and commercial infrastructure to prepare for future market launches.
“We are proud of the decision from the European Commission to authorise the use of donidalorsen in HAE. This represents another key milestone in the collaboration between Otsuka and Ionis which aims to address unmet need in a challenging rare disease,” said Andy Hodge, President and CEO at Otsuka Pharmaceutical Europe Ltd. “We would like to thank all those at Otsuka and Ionis whose commitment has helped us introduce this medicine to HAE patients.”
The decision follows the positive opinion issued by the Committee for Medicinal Products for Human Use (CHMP) in November 2025. The new authorisation applies to all 27 EU member states, as well as Iceland, Liechtenstein, and Norway.
About Otsuka
Otsuka Pharmaceutical Co., Ltd. is a total healthcare company that focuses on each individual’s potential to enhance their well-being. Our medical-related business provides treatments and diagnostics for both physical and mental health. Our nutraceutical business supports daily health maintenance and improvement. Otsuka’s products and services are based on scientific evidence, under the guidance of our corporate philosophy: Otsukapeople creating new products for better health worldwide. Otsuka Europe employs around 500 people and focuses on psychiatric and neurologic disorders, nephrology and
immunology, haemato-oncology, and digital therapeutics. For further information on Otsuka, please visit www.otsuka-europe.com.
