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Immune & inflammation

Icatibant

A synthetic decapeptide that blocks bradykinin B2 receptors, approved for acute attacks of hereditary angioedema in adults.

L5Practice-changingApproved — narrow indicationApprovedHigh confidenceLast reviewed 2026-08-23
SC injection

Also known as: Firazyr, icatibant acetate

Evidence passport

Last reviewed 2026-08-23

Evidence level
L5Practice-changing
Confidence
High confidence
Human efficacy
75/100
Human safety
75/100
Regulatory status
Approved — narrow indication
Development
Approved
Routes
SC injection
Evidence base
Includes human data
Furthest stage
Approved
Source curation
Sources fully curated
Clinical maturity
Approved rare-disease medicine

Overview

Human evidence75/100
Preclinical evidence65/100
Human safety evidence75/100

Clinical maturity: Approved rare-disease medicine

Routes & formulations

Studied / approved routes

SC injection

The approved product is a subcutaneous injection used to treat acute attacks; patients are typically trained to administer it under clinical guidance.

Route availability is not evidence of efficacy, and evidence from one route does not transfer to another. The Registry never provides dosing or sourcing information.

Peptide lifecycle

  1. Discovery

  2. Preclinical

  3. Phase I

  4. Phase II

  5. Phase III

  6. Approved

Approved

What it is

A ten-amino-acid synthetic peptide antagonist of the bradykinin B2 receptor, intercepting the peptide signal that drives angioedema swelling.

What people claim

  • Treats acute hereditary angioedema attacks

What the evidence actually says

Randomised controlled trials in hereditary angioedema supported approval for acute attacks. It is a tidy example of peptide-versus-peptide pharmacology: one synthetic peptide blocking the receptor for another.

Human evidence

  • Randomised controlled trials in acute hereditary angioedema attacks.

Preclinical evidence

  • Bradykinin-receptor pharmacology.

Animal and cell findings are Level 1–2 evidence.

Mechanism and pathways

  • Competitive B2-receptor antagonism blocks bradykinin-driven vascular permeability and swelling.

Safety and unknowns

  • Injection-site reactions are the most common labelled effects.
  • Label guidance covers laryngeal attacks requiring medical follow-up.

Cancer relevance

No concern identified

No established human cancer signal within approved use.

Regulatory status

FDA-approved (Firazyr) for treatment of acute attacks of hereditary angioedema in adults 18 years and older, given by subcutaneous injection.

Evidence grade

L5Practice-changingHigh confidence

Replicated large randomised trials, pivotal Phase 3 programmes, or a major regulatory decision.

What would change our rating?

  • Not applicable at this evidence tier.

References and sources

Sources fully curated

Source hierarchy: regulatory documents and trial registries first, peer-reviewed work next, sponsor material flagged as non-independent. We never use supplier or clinic marketing as evidence, and where a verified source has not yet been curated we say so rather than inventing one.

Evidence change history

No recorded changes yet. Baseline position set on 2026-08-23.