Ionis Pharmaceuticals Releases Long-Term Data For Dawnzera Showing Durable Efficacy And Safety

Author: Benzinga Newsdesk | November 06, 2025 08:19am

• DAWNZERA showed durable efficacy, demonstrating 94% overall mean HAE attack rate reduction at one year in OASISplus open-label extension study
• Patients in OASISplus switch study achieved 68% improvement in mean HAE attack rate compared to prior prophylactic therapy one year after switching to DAWNZERA
• Long-term efficacy and safety maintained up to four years in Phase 2 open-label extension

Ionis Pharmaceuticals, Inc. (NASDAQ:IONS) today announced new long-term data for DAWNZERA™ (donidalorsen), the first and only RNA-targeted prophylactic medicine for hereditary angioedema (HAE), to be presented at the 2025 American College of Allergy, Asthma & Immunology (ACAAI) Annual Scientific Meeting in Orlando, Florida. Results demonstrate the long-term durability and safety of DAWNZERA, including new data from patients who were followed for one year in the ongoing OASISplus open-label extension (OLE) and switch cohorts, as well as new four-year results from the Phase 2 OLE study.

DAWNZERA was recently approved by the U.S. Food and Drug Administration for prophylaxis to prevent attacks of HAE in adult and pediatric patients 12 years of age and older.

"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," said Kenneth Newman, M.D., senior vice president, clinical development, Ionis. "The latest results from across our clinical studies support the strong and durable efficacy and safety profile of DAWNZERA. Presentations at the congress offer patients and physicians valuable insights to support informed treatment decisions, including when transitioning to DAWNZERA from a previous prophylactic therapy."

The OASISplus OLE cohort enrolled adult and adolescent patients continuing from the Phase 3 OASIS-HAE pivotal trial, who received DAWNZERA every four (Q4W) or every eight weeks (Q8W). At Week 52 in the OLE, DAWNZERA demonstrated a 94% and 95% mean attack reduction from baseline for patients in the Q4W (n=69) and Q8W (n=14) dosing groups, respectively. Nearly all (97%) patients reported well-controlled disease as measured by the Angioedema Control Test (AECT score ≥10) at Week 52 compared to baseline.

OASISplus also included a switch cohort evaluating DAWNZERA Q4W in patients previously treated with lanadelumab, C1-esterase inhibitor or berotralstat. At Week 52, patients who switched to DAWNZERA (n=64) experienced a 68% improvement in monthly HAE attack rate compared to baseline with prior prophylactic therapy, with 90% reporting well-controlled disease as measured by the AECT.

In the Phase 2 OLE study, patients treated with DAWNZERA Q4W showed a 97% mean HAE attack rate reduction over four years. The median attack-free interval was 2.7 years, and 71% of patients were attack-free for more than one year.

Across all studies, DAWNZERA demonstrated a favorable long-term safety and tolerability profile. The majority of treatment-emergent adverse events (TEAEs) were mild or moderate, with no serious TEAEs related to DAWNZERA.

Posted In: IONS