Immune
Ecallantide
A recombinant plasma kallikrein inhibitor for acute hereditary angioedema attacks, given under medical supervision.
What it is
Ecallantide is a recombinant 60-amino-acid protein that inhibits plasma kallikrein, the enzyme that releases bradykinin. It is licensed in the US (Kalbitor) for acute hereditary angioedema attacks, and because of a small but real risk of anaphylaxis it must be given where resuscitation is available - it is not licensed for self-administration.
How it works
- 1
Binds and inhibits plasma kallikrein.
- 2
Blocks the release of bradykinin from high-molecular-weight kininogen.
- 3
Removes the vasodilatation and capillary leakage that drive swelling.
- 4
Works upstream of the bradykinin receptor, unlike icatibant.
- 5
Half-life of about two hours, so repeat dosing may be needed.
What it's studied for
Reported and studied effects
- Median time to meaningful symptom improvement of roughly 2 hours in EDEMA4
- Significant improvement in composite symptom scores versus placebo
- Anaphylaxis risk of a few percent, which dictates the supervision requirement
Research protocol notes
Research context onlyResearch context only - a supervised clinical treatment. Licensed dosing is 30 mg subcutaneously, given as three 10 mg injections, with a further 30 mg possible within 24 hours if the attack recurs; patients are observed for anaphylaxis for at least an hour, and the EDEMA trials measured a composite symptom score change over 4 hours.
These figures are described so you can understand what researchers did. They are not a dose, a schedule, or a suggestion — and they are not a substitute for a doctor.
Possible side effects and contraindications
Safety profile
Possible side effects
- Anaphylaxis, including in patients without prior exposure
- Headache
- Nausea and diarrhoea
- Injection-site reactions
- Fever
- Rare antibody formation
Contraindications and cautions
- Prior hypersensitivity to ecallantide
- Must be administered where anaphylaxis can be managed
- Pregnancy only if clearly needed
- Not for histamine-mediated angioedema
A side-effect list is never complete, and these are not the only situations that warrant caution. Anything unexpected, or anything you are unsure about, should be discussed with a doctor before use.
Evidence assessment
Two randomised controlled trials of moderate size, one of which met its primary endpoint and one of which did not, plus a real anaphylaxis signal.
References
- 01Levy et al., EDEMA4: a phase 3, double-blind study of subcutaneous ecallantide treatment for acute attacks of hereditary angioedema, Annals of Allergy, Asthma and Immunology 2010
- 02FDA - Kalbitor (ecallantide) prescribing information
References link to published literature, regulator pages or literature indexes. Where a link points to a search, it collects the peer-reviewed work on that molecule rather than a single study.
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A bradykinin receptor blocker given under the skin to abort hereditary angioedema attacks.