Real-world data suggest that patients with hereditary angioedema (HAE) experience significant treatment burden associated with US Food and Drug Administration (FDA)-approved on-demand therapies for HAE attacks, according to a study published in Annals of Allergy, Asthma & Immunology.

“Results generally support those found in clinical trials, particularly for icatibant, for which 97% of patients experience injection-site reactions,” the authors said.

Icatibant (Firazyr®) had the highest rate of adverse drug reactions per year for site pain, erythema, and swelling, whereas access site complications and malfunctions were highest for recombinant C1 inhibitor. Human C1 inhibitor and ecallantide (Kalbitor®) had the lowest adverse drug reaction rates per year (less than 2).

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Considering all drugs, the most frequently reported adverse drug reaction domains were injection site pain, erythema, swelling, and access site complications or malfunctions. Adverse drug reaction rates were based on spontaneous reporting rather than exposure-adjusted.

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Tachdjian et al searched the FDA’s Adverse Event Reporting System for administration site adverse drug reactions reported for human C1 inhibitor, ecallantide, icatibant, and recombinant C1 inhibitor from October 1, 2009 to March 31, 2021.

The treatment of HAE has evolved during the last 2 decades, with the FDA approving several pharmacological agents to manage HAE attacks, including including Cinryze® (C1-esterase inhibitor [human]), Berinert® (C1-esterase inhibitor [human]), Kalbitor® (ecallantide), Firazyr® (icatibant), and Ruconest® (C1 Esterase inhibitor [recombinant]). In addition, long-term prophylaxis against acute HAE attacks can be considered for HAE patients.

Current guidelines from the World Allergy Organization/European Academy of Allergy and Clinical Immunology and the US Hereditary Angioedema Association Medical Advisory Board recommend on-demand treatment for all HAE attacks. If first-line therapies are not available, HAE attacks can be treated with solvent detergent-treated plasma or fresh frozen plasma.


Tachdjian R, Savic S, Fridman M, Frade J, Audhya P, Fasehun M. Real-world treatment burden associated with parenteral on-demand therapies for hereditary angioedema. Ann Allergy Asthma Immunol. 2022;129(5, Supplement):S15-S16. doi: