Benralizumab
Biologics for asthma
Biologics for asthma
An antibody against the IL-5 receptor that removes eosinophils, used as add-on treatment in severe eosinophilic asthma and in EGPA.
Quick facts
- Group
- Biologics for asthma
- Target
- Interleukin-5 receptor alpha chain (IL-5Rα)
- Used for
- Eosinophilic granulomatosis
- Key effects
- Headache · Sore throat · Injection-site reactions
- Monitor
- Blood eosinophil count · Exacerbations
- ATC
- R03DX10
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows IL-5 bound to the human IL-5 receptor alpha chain (crystal structure). Benralizumab binds this receptor chain; the antibody itself is not in the model.
Benralizumab is a humanised IgG1 monoclonal antibody against the alpha chain of the interleukin-5 receptor, which sits mainly on eosinophils. It blocks IL-5 signalling and, unlike the antibodies that only capture IL-5, it is cytolytic: it marks eosinophils for destruction, so they are depleted from blood and airway tissue. Exacerbations and the need for oral corticosteroids fall in eosinophilic asthma.
- Benralizumab binds IL-5 receptor alpha on eosinophils
- IL-5 can no longer signal through the receptor
- Bound eosinophils are destroyed and depleted
- Eosinophilic inflammation and flare-ups fall
Indications
- Severe eosinophilic asthma not controlled by current treatment, as add-on maintenance in adults and children from six years Asthma →
- Eosinophilic granulomatosis with polyangiitis (EGPA) in adults Eosinophilic granulomatosis with polyangiitis (Churg–Strauss) →
Adverse effects
Common
- Headache
- Sore throat
- Injection-site reactions
Contraindications
- Hypersensitivity to benralizumab
- Not for an acute asthma attack or bronchospasm
- A worm (helminth) infection is reported and treated first
Key interactions
- Other asthma medicines, including corticosteroids
- Are not reduced or stopped without medical supervision
What is monitored
- Blood eosinophil count (selection)
- Exacerbations and oral corticosteroid use
- Allergic reactions after injections
Administration and safety
- Subcutaneous injection into the upper arm, thigh or abdomen, usually in a clinic
- An autoinjector may be used at home after training; each device is single-use
- Avoid the area around the navel and tender, bruised, red, hard or scarred skin
Pregnancy and breastfeeding
Data in pregnancy are limited; antibodies cross the placenta, and use is decided with the specialist.
Nursing care
- Ask about worm infections before starting
- Teach the signs of an allergic reaction
- Remind that it does not treat an attack: the rescue inhaler is still needed
- Other asthma medicines are not stopped on the patient's own
Pharmacokinetics
- Absorption
- Subcutaneous injection
- Elimination
- Broken down like other antibodies (proteolysis)
- Onset and duration
- Blood eosinophils fall quickly; clinical benefit builds over months
Test yourself
Think of the answer, then tap the question to see it.
What does benralizumab bind, and how is that different from mepolizumab?
The IL-5 receptor alpha chain on eosinophils; mepolizumab binds IL-5 itself.
Why does benralizumab deplete eosinophils rather than just block them?
It is cytolytic: once bound, the eosinophil is destroyed.
Which non-asthma condition is an indication for benralizumab?
Eosinophilic granulomatosis with polyangiitis (EGPA).
Connections
← Back to the class: Biologics for asthma
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Benralizumab Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); RCSB PDB - 3VA2: Crystal structure of human Interleukin-5 in complex with its alpha receptor (RCSB Protein Data Bank, 2012); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.