Although it is a rare disease, HAE is an autosomal dominant disorder
that can be potentially life-threatening when swelling manifests itself
within the upper airways. Antagonism of the constitutively expressed B2
receptor, therefore, would not only be beneficial in the treatment of HAE but also find application in inflammatory, allergic, and hyperalgesic
disorders.Designed to possess enhanced metabolic stability with the
inclusion of five non-proteinogenic amino acids, icatibant is a competitive and selective B2 receptor antagonist (devoid of activity against
the inducible B1 receptor) with a Ki of 2.2±0.7 nM, and it is the first
downstream targeting agent to receive regulatory approval. It joins
purified C1 esterase inhibitor, danazol (an attenuated androgen), and
tranexamic acid (an antifibrinolytic agent) as acute and prophylactic
treatments for HAE.