Benralizumab Dosing for Severe Asthma
The recommended dosing regimen for benralizumab in patients with severe asthma is 30 mg administered subcutaneously every 4 weeks for the first three doses, followed by every 8 weeks thereafter. 1
Dosing Details
Benralizumab (FASENRA) is an anti-interleukin-5 receptor alpha subunit monoclonal antibody that works by directly binding to the alpha subunit of the human interleukin-5 receptor, leading to apoptosis of eosinophils and basophils through antibody-dependent cell-mediated cytotoxicity (ADCC). 1
The dosing schedule follows a specific pattern:
- Initial phase: 30 mg subcutaneously every 4 weeks for the first three doses
- Maintenance phase: 30 mg subcutaneously every 8 weeks thereafter
Clinical Evidence Supporting This Regimen
The recommended dosing regimen is based on robust clinical evidence from multiple phase III trials:
The SIROCCO and CALIMA trials demonstrated that benralizumab 30 mg administered every 8 weeks (with first three doses given every 4 weeks) significantly reduced annual exacerbation rates by 49% compared to placebo in patients with severe eosinophilic asthma. 2
Long-term safety and efficacy data from the BORA extension trial confirmed that this dosing regimen maintains its effectiveness and safety profile over extended periods (up to 2 years), with no new consequences of long-term eosinophil depletion observed. 3
Patient Selection and Response Predictors
Benralizumab is most effective in patients with:
- Blood eosinophil counts ≥300 cells/μL (strongest evidence)
- However, efficacy is also demonstrated in patients with counts ≥150 cells/μL 4
- History of frequent exacerbations (two or more in the previous year) 5
The combination of higher blood eosinophil counts and more frequent exacerbation history is associated with greater improvements in exacerbation rates. 5
Administration Considerations
- Benralizumab is administered as a subcutaneous injection
- Available in single-dose prefilled syringes or autoinjectors containing 30 mg/mL 1
- Can be administered in the upper arm, thigh, or abdomen
- Should be stored at 2-8°C (refrigerated) and protected from light
Special Populations
- No dose adjustment is required based on age, gender, race, or renal function 1
- No formal studies have been conducted in patients with hepatic impairment, but as an IgG monoclonal antibody, benralizumab is not primarily cleared via hepatic pathways 1
- For pediatric patients aged 6-11 years weighing ≥35 kg, the adult dose of 30 mg is recommended 1
Common Pitfalls and Caveats
Monitoring for hypersensitivity reactions: Headache, fever, and local injection site reactions can occur. Anaphylaxis has been reported in rare cases. 6
Anti-drug antibodies: Approximately 13% of patients may develop anti-drug antibodies to benralizumab, with 12% developing neutralizing antibodies. High titers may be associated with increased clearance of benralizumab and reduced efficacy. 1
Not for acute bronchospasm: Benralizumab is not indicated for the relief of acute bronchospasm or status asthmaticus. It is a maintenance treatment for severe asthma.
Parasitic infections: Patients with known parasitic infections should be treated before initiating benralizumab, as anti-IL-5 therapies may affect immune responses against helminthic infections.
By following this dosing regimen, benralizumab has been shown to effectively reduce exacerbations, improve lung function, and allow for reduction in oral corticosteroid use in patients with severe eosinophilic asthma.