Icatibant is a synthetic 10-amino-acid peptidomimetic (MW ~1304.5 g/mol) that acts as a selective, competitive antagonist of the bradykinin B2 receptor. It was FDA-approved in August 2011 (Firazyr) for the treatment of acute attacks of hereditary angioedema (HAE) in adults. Icatibant contains five non-natural amino acids that confer resistance to enzymatic degradation and selectivity for the B2 receptor, and is self-administered as a subcutaneous injection.
Category: Rare Disease / Bradykinin Antagonist. Evidence rating: A (strong human clinical data).
Clinical status: FDA-approved (Firazyr for acute HAE attacks, August 2011)
Icatibant is a competitive antagonist at the bradykinin B2 receptor. In hereditary angioedema (HAE), deficiency or dysfunction of C1-esterase inhibitor leads to uncontrolled activation of the kallikrein-kinin system and excessive bradykinin generation. Bradykinin binding to B2 receptors on…
Safety considerations: Very common (>=10%): injection site reactions (97% — erythema, swelling, burning, pruritus at injection site; typically mild and self-limiting within hours); Common (1-10%): pyrexia, transient liver enzyme elevations, dizziness, headache, nausea, rash; No serious drug-related adverse events reported in pivotal clinical trials.
Reviewed by the PeptideAtlas Editorial Team.
| Amino-acid sequence | D-Arg-Arg-Pro-Hyp-Gly-Thi-Ser-D-Tic-Oic-Arg |
|---|---|
| Molecular weight | ~1304.5 g/mol |
| CAS number | 130308-48-4 |
| Half-life | ~1-2 hours |
| Bioavailability | ~97% subcutaneous |
| Production method | synthetic |
| Anti-doping status | not-listed |
| US regulatory status | FDA-approved (Firazyr, August 2011) for acute HAE attacks in adults 18 years and older. Generic versions approved. |
In clinical trials, the median time to onset of symptom relief was approximately 2 hours after subcutaneous injection. Most patients experienced clinically meaningful improvement within 2-5 hours. A second dose may be administered after 6 hours if symptoms persist, up to a maximum of 3 injections in 24 hours.
Icatibant has been studied off-label for ACE inhibitor-induced angioedema, which is also bradykinin-mediated. Small studies and case series suggest efficacy, but it is not FDA-approved for this indication. Larger trials are ongoing.
No. Icatibant is an on-demand treatment for acute HAE attacks only. It is not indicated for prophylaxis. Preventive HAE treatments include lanadelumab (Takhzyro), berotralstat (Orladeyo), and C1-esterase inhibitor concentrates.