Dawnzera safely prevents HAE swelling attacks for up to 4 years
Newly approved therapy shows long-term effectiveness in 2 studies
Long-term treatment with Dawnzera (donidalorsen) — approved in the U.S. earlier this year for people with hereditary angioedema (HAE) — effectively reduced swelling attacks in HAE patients in two clinical trial extension studies, according to new data.
The newly reported results were based on data from patients who were followed for one year in the Phase 3 OASISplus (NCT05392114) study and for up to four years in a Phase 2 (NCT04307381) study in the U.S. and the Netherlands.
The findings were presented at the American College of Allergy, Asthma & Immunology’s (ACAAI) 2025 Annual Scientific Meeting, held earlier this month in Orlando, Florida.
“These new long-term data support our belief that Dawnzera, which is now available to people living with HAE in the U.S., is well-positioned to transform the treatment paradigm for HAE,” Kenneth Newman, MD, senior vice president of clinical development at Ionis, Dawnzera’s developer, said in a company press release.
The “presentations at the congress [offered] patients and physicians valuable insights to support informed treatment decisions, including when transitioning to Dawnzera from a previous prophylactic therapy,” Newman added.
HAE is characterized by swelling attacks triggered by the overproduction of bradykinin, a signaling molecule that causes blood vessels to become more permeable. This allows fluid to leak into nearby tissues, causing the disease’s symptoms.
Dawnzera approved in US in August for HAE patients 12 and older
Dawnzera is a subcutaneous (under-the-skin) injection therapy approved in the U.S. in August for use in preventing swelling attacks in people ages 12 and older with HAE. It works by reducing the production of prekallikrein, a precursor of kallikrein, an enzyme needed for bradykinin production.
The OASISplus study enrolled adolescents and adults with HAE who had participated in the Phase 3 OASIS-HAE (NCT05139810) pivotal trial, as well as some patients who’d never received Dawnzera and had been on other prophylactic therapies. The study demonstrated that Dawnzera significantly reduced HAE attacks compared with a placebo, supporting the treatment’s U.S. approval. Participants in OASISplus received Dawnzera once a month or every other month.
After one year, Dawnzera reduced the monthly HAE attack rates by 94% when given once monthly and by 95% when given every other month. Additionally, patients reported a clinically meaningful improvement in quality of life, and nearly all (97%) considered their disease well-controlled, defined as a score of 10 or higher in the Angioedema Control Test.
The latest results from across our clinical studies support the strong and durable efficacy and safety profile of Dawnzera.
An analysis of the study results, based on patients’ baseline attack rates, demonstrated that participants with two or fewer monthly attacks at baseline — the start of the study — experienced the longest period without attacks. The median duration of the longest attack-free interval was 359 days, or nearly one year, and 79% of participants remained free from attacks for six months.
For participants with more than five monthly attacks, the longest period without attacks was 133 days, or approximately 4.5 months, with 43% remaining attack-free for six months or longer.
In patients previously treated with Takhzyro (lanadelumab), a C1-esterase inhibitor, or Orladeyo (berotralstat) who switched to Dawnzera, monthly HAE attack rates decreased by 68%. Additionally, 90% of patients reported that the disease was well controlled and their quality of life had improved.
In the Phase 2 study extension study, patients treated with Dawnzera once monthly showed a 97% mean reduction in HAE attack rates over four years, while those receiving treatment once every two months experienced an 83% reduction. The median longest attack-free interval was 2.7 years, and 71% of the patients were attack-free for more than one year.
Dawnzera demonstrated a favorable long-term safety and tolerability profile in all studies, with most treatment-emergent adverse events being mild or moderate. No serious adverse events were considered related to the treatment, and early treatment discontinuation rates were low.
“The latest results from across our clinical studies support the strong and durable efficacy and safety profile of Dawnzera,” Newman said.
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