A new study has found that donidalorsen, an antisense prekallikrien inhibitor, was well-tolerated and effective in reducing hereditary angioedema (HAE) attacks in patients 18 and older.

The study, published in the Journal of Allergy and Clinical Immunology, will be presented at the 2023 American Academy of Allergy, Asthma and Immunology (AAAAI) Annual Meeting from February 24 -27 in San Antonio, Texas.

HAE is a rare disease characterized by episodes of disabling swelling in the limbs, face, gastrointestinal tract and airway. It is an autosomal dominant disorder generally caused by a deficiency or dysfunction of C1 inhibitor (C1-INH); however a new type of HAE in individuals with normal C1-INH has recently been identified.

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The research team conducted an open-label extension study (NCT04307381) on 8 adult patients with HAE who completed week 17 of the NCT04030598 trial, with the aim of examining the safety of extended vs alternative dosing and/or dose frequency of donidalorsen.

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The on-treatment period included fixed and flexible dosing periods. The fixed period dose was weeks 1-13 of 80 mg donidalorsen subcutaneously every 4 weeks, and the flexible period was weeks 17-53 and included 80 mg donidalorsen every 4 weeks, 80 mg every 8 weeks, or 100 mg every 4 weeks.

Primary outcome measures included changes in plasma prekallikrien levels and angioedema quality of life scores.

The results revealed that overall, donidalorsen every 8 weeks was effective in reducing HAE attack rates and was well tolerated by the participants, the study authors wrote. Eight patients in the flexible period switched to 80 mg every 8 weeks, 5 were attack-free and stayed on this regimen, and 3 had attacks and switched back to 80 mg every 4 weeks, which resulted in fewer attacks.

Overall, there was a 76% reduction in attacks in all 8 patients, and 62.5% of the participants were attack-free at the end of the study period.


Newman K, Riedl M, Lui C, et al. The impact of donidalorsen taken every 8 weeks in patients with hereditary angioedema. J Allergy Clin Immunol. 2023;(151)2:AB134. doi:10.1016/j.jaci.2022.12.420.