FDA

Dawnzera approved for prophylaxis of hereditary angioedema

August 25, 2025

Brand name: Dawnzera

Generic name: donidalorsen

Manufacturer: Ionis Pharmaceuticals

Approval date: August 21, 2025

FDA approved Dawnzera (donidalorsen), a prekallikrein-directed antisense oligonucleotide, for prophylaxis to prevent attacks of hereditary angioedema (HAE) in adult and pediatric patients ≥12 years of age.

According to a manufacturer press release, Dawnzera is the first RNA-targeted medicine approved for HAE, designed to target plasma prekallikrein (PKK), a key protein that activates inflammatory mediators associated with acute attacks of HAE.

Efficacy

Approval was based on positive results from the phase 3, multicenter, randomized, double-blind, placebo-controlled OASIS-HAE study (NCT05139810) in patients with HAE. The study met its primary endpoint, with Dawnzera q4wks significantly reducing monthly HAE attack rate by 81% compared with placebo over 24 weeks. Mean attack rate reduction increased to 87% when measured from the second dose, a key secondary endpoint. Additionally, Dawnzera q4wks reduced moderate-to-severe HAE attacks by approx. 90% over 24 weeks when measured from the second dose.

The results are supplemented by the ongoing OASISplus open-label extension (OLE) study, in which Dawnzera q8wks had a similar effect as q4wks over time. Dawnzera resulted in a 94% total mean attack rate reduction from baseline across both dosing groups after one year in the OLE.

The OASISplus study also includes a switch cohort evaluating Dawnzera q4wks in patients previously treated with lanadelumab, C1-esterase inhibitor or berotralstat for at least 12 weeks. Switching to Dawnzera reduced mean HAE attack rate by 62% from prior prophylactic treatment over 16 weeks, with no mean increase in breakthrough attacks observed during the switch. 84% of patients surveyed preferred Dawnzera over their prior prophylactic treatment, citing better disease control, less time to administer and less injection site pain or reactions.

Safety

Most common adverse reactions (incidence ≥5%) reported in clinical trials were injection site reactions, upper respiratory tract infection, UTI, and abdominal discomfort.

Recommended dose

Dawnzera 80mg is self-administered via SC autoinjector either q4wks or q8wks.

Sources:

Dawnzera™ (donidalorsen) approved in the US as first and only RNA-targeted prophylactic treatment for hereditary angioedema. [News release]. 2025. https://ir.ionis.com/news-releases/news-release-details/dawnzeratm-donidalorsen-approved-us-first-and-only-rna-targeted

Dawnzera (donidalorsen) [package insert]. Ionis Pharmaceuticals. https://ionis.com/medicines/DAWNZERA/DAWNZERA-FPI.pdf Revised August 2025. Accessed August 22, 2025.