Icatibant (Firazyr)

Written by The Peptide Record editorialClinical review not yet completedLast reviewed 12 September 2026

Icatibant is a real, FDA-approved bradykinin-receptor blocker for acute attacks of hereditary angioedema — a genuinely rare disease with previously few acute-treatment options. Its trial base is real but smaller and more mixed than most drugs on this site: three separate trials against two different comparators, and the very first one (FAST-1) didn't reach statistical significance against placebo. The later trials did. The honest read is a real, working rescue treatment for a rare emergency, built on a genuinely smaller and more heterogeneous evidence base than a first glance suggests.

In brief

Should you care? Yes if hereditary angioedema is a live concern — icatibant is a real, on-demand rescue treatment with genuine trial support, but a rarer-disease evidence base with more moving parts than most drugs covered here.

The short version

FDA-approved August 25, 2011 (Firazyr) for acute attacks of hereditary angioedema in adults.
Backed by three trials (FAST-1, FAST-2, FAST-3) against two different comparators — placebo and, in one trial, oral tranexamic acid.
FAST-1 missed its primary endpoint against placebo (2.5h vs. 4.6h, p=0.14); FAST-2 (vs. tranexamic acid, 2.0h vs. 12.0h, p<0.001) and FAST-3 (vs. placebo, 2.0h vs. 19.8h, p<0.001) both hit theirs clearly.

What it is, and its real 2011 approval

Icatibant is a synthetic decapeptide that selectively blocks the bradykinin B2 receptor. In hereditary angioedema (HAE), a genetic C1-esterase-inhibitor deficiency leads to excess bradykinin generation, which drives the disease's characteristic swelling attacks; blocking the B2 receptor directly counters that mechanism. FDA approved icatibant (as Firazyr, Shire/Takeda) on August 25, 2011, for acute HAE attacks in adults, delivered as a single subcutaneous injection from a room-temperature-stable prefilled syringe.

The FAST trials — one miss, two hits

Icatibant's approval rested on three randomized trials: FAST-1 and FAST-2 (Cicardi et al., N Engl J Med 2010;363(6):532-541, DOI 10.1056/NEJMoa0906393) and FAST-3 (Lumry et al., Ann Allergy Asthma Immunol 2011;107(6):529-537). FAST-1 compared icatibant against placebo and did not reach statistical significance on its primary endpoint (median time to clinically significant symptom relief: 2.5 hours with icatibant vs. 4.6 hours with placebo, p=0.14). FAST-2 compared icatibant against oral tranexamic acid, a real active comparator rather than placebo, and found a clear, highly significant benefit (2.0 hours vs. 12.0 hours, p<0.001). FAST-3, placebo-controlled again, also found a clear benefit (2.0 vs. 19.8 hours, p<0.001).

Not a uniformly clean trial record

One of icatibant's three pivotal trials missed its primary endpoint against placebo. That doesn't erase the two trials that succeeded — but it's worth knowing before treating the FAST program as an unambiguous, uniformly positive result.

What the successful trials actually showed

Across FAST-2 and FAST-3 specifically, icatibant produced meaningfully faster symptom relief than either tranexamic acid or placebo — a real, clinically relevant difference for an acute-attack rescue drug, especially for HAE's most dangerous presentation, laryngeal attacks, where delayed relief is a genuine mortality risk.

Who it's for

Icatibant is approved only for adults with confirmed hereditary angioedema — not for other forms of angioedema, and not as a preventive therapy (separate long-term prophylactic drugs exist for that). Its most consistently reported adverse effect is near-universal injection-site reactions, which the label frames as expected and generally self-limited rather than a reason to withhold treatment during a genuine attack.

References

FDA approval of Firazyr (icatibant), 25 August 2011, for acute attacks of hereditary angioedema in adults.
Cicardi M, Banerji A, Bracho F, et al., "Icatibant, a New Bradykinin-Receptor Antagonist, in Hereditary Angioedema," N Engl J Med 2010;363(6):532-541, DOI 10.1056/NEJMoa0906393 (FAST-1 and FAST-2).
Lumry WR, Li HH, Levy RJ, et al., "Randomized placebo-controlled trial of the bradykinin B2 receptor antagonist icatibant for the treatment of acute attacks of hereditary angioedema: the FAST-3 trial," Ann Allergy Asthma Immunol 2011;107(6):529-537.