Icatibant

Icatibant is a synthetic ten-amino-acid peptide developed as HOE140 and marketed as Firazyr, with generics also available. Hereditary angioedema produces episodic severe skin, abdominal or airway swelling. FDA approval was in 2011.

C1-inhibitor deficiency or dysfunction in HAE allows excessive bradykinin, which activates vascular B2 receptors, causing dilation and leakage into tissue. Icatibant competitively blocks B2 receptors, interrupting that downstream swelling signal regardless of the upstream bradykinin source.

In FAST-3, median time to meaningful symptom relief was approximately two hours with icatibant versus 20 hours with placebo. This acute-attack result does not establish treatment for all causes of swelling.

FDA approved icatibant in 2011 for acute HAE attacks in adults. Patients are trained to inject the subcutaneous abdominal formulation at attack onset. Airway or laryngeal attacks still need medical attention and monitoring, including after treatment because symptoms may be delayed.

Redness, swelling, pain and itching at injection sites are nearly universal. Fever and dizziness also occur, and hives have been reported after approval. The potential severity of airway swelling remains a clinical priority beyond local injection reactions.