benralizumab
Brand: Fasenra
Prototype: mepolizumab
Drug Class: biologic — anti-interleukin-5 receptor alpha (anti-IL-5Ralpha) monoclonal antibody
Drug Family: biologic
Subclass: anti-eosinophilic biologic — IL-5Ralpha antagonist
Organ Systems: respiratoryimmunology
Mechanism of Action
Humanized monoclonal antibody that directly binds the alpha subunit of the IL-5 receptor on eosinophils and basophils; binding recruits natural killer cells (via enhanced ADCC via afucosylated Fc region), causing direct eosinophil apoptosis and depletion; reduces eosinophil counts to near-zero levels, eliminating eosinophilic airway inflammation.
interleukin-5 receptor alpha (IL-5Ralpha) on eosinophils and basophils
Indications
- severe eosinophilic asthma (add-on maintenance therapy, adults and adolescents 12 years or older)
- eosinophilic granulomatosis with polyangiitis (EGPA)
Contraindications
- hypersensitivity to benralizumab
Adverse Effects
Common
- injection site reactions
- headache
- pharyngitis
- hypersensitivity reactions (urticaria, rash)
Serious
- anaphylaxis (rare)
- helminth infections (eosinopenia may impair defense against parasites)
Pharmacokinetics (ADME)
| Absorption | subcutaneous injection; bioavailability approximately 59%; Tmax approximately 7 days |
| Distribution | Vd approximately 3.0-3.4 L; IgG1 distribution |
| Metabolism | proteolytic degradation to amino acids and peptides |
| Excretion | proteolytic catabolism; no renal or hepatic clearance |
| Half-life | approximately 15.5 days |
| Onset | eosinophil depletion within 24-48 hours; clinical benefit over weeks |
| Peak | approximately 7 days post-injection |
| Duration | doses every 8 weeks after initial loading doses |
| Protein Binding | N/A (monoclonal antibody) |
| Vd | approximately 3.0-3.4 L |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| live vaccines | immunosuppression from eosinophil depletion may reduce vaccine response; avoid live vaccines during therapy | moderate |
Nursing Considerations
- Administer 30 mg subcutaneously every 4 weeks for 3 doses, then every 8 weeks; refrigerate and allow to reach room temperature for 30 minutes before injection; do not shake — gently roll vial.
- Observe patients for 30-60 minutes after the first two injections to detect hypersensitivity reactions; epinephrine and resuscitation equipment should be available in the administration setting.
- Screen for parasitic infections (especially in endemic areas) before initiating benralizumab; eosinophil depletion may impair the immune response to helminth infections.
- Instruct patients that benralizumab is an add-on maintenance therapy that does not replace ICS, LABA, or rescue SABA therapy; acute asthma attacks require conventional rescue treatment.
Clinical Pearls
- Benralizumab's mechanism of directly causing eosinophil apoptosis (via ADCC) is unique compared with mepolizumab and reslizumab, which only block IL-5 signal transduction; this direct depletion achieves near-complete eosinophil reduction and may be more effective in high eosinophil burden disease.
- The every-8-week maintenance dosing schedule (after loading) is one of the least frequent injection schedules among biologics for asthma, improving real-world adherence relative to monthly injection regimens.
Safety Profile
Pregnancy avoid
Lactation insufficient-data
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Guideline Update pending
Concordance Terms
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