Biologics for asthma
Injected monoclonal antibodies that block IgE or type 2 cytokines (IL-5, IL-4/IL-13) in severe allergic or eosinophilic asthma.
What they are
Asthma biologics are add-on treatments for severe asthma that stays uncontrolled despite high-dose inhaled corticosteroid plus a second controller. The choice follows the patient's phenotype: omalizumab (anti-IgE) for allergic asthma with raised IgE and a proven allergen; mepolizumab, reslizumab (anti-IL-5) and benralizumab (anti-IL-5 receptor) for eosinophilic asthma; dupilumab (anti-IL-4 receptor alpha, blocking IL-4 and IL-13) for type 2 asthma and atopic dermatitis; tezepelumab (anti-TSLP) for a broader range. They reduce exacerbations and the need for oral corticosteroids; they do not treat an acute attack.
Mechanism of action
Type 2 inflammation drives most severe asthma. Allergen-specific IgE sits on the high-affinity receptor (FcεRI) of mast cells and basophils and triggers their degranulation. IL-5 makes eosinophils mature, survive and enter the airway. IL-4 and IL-13 switch B cells to IgE, increase mucus and airway hyperresponsiveness. Each biologic removes one link: anti-IgE captures free IgE; anti-IL-5 antibodies starve eosinophils; anti-IL-4Rα blocks the receptor shared by IL-4 and IL-13.
Target: IgE, IL-5 and the IL-4 receptor alpha chain (type 2 inflammation)
Drugs in this class
- OmalizumabAn anti-IgE antibody injected under the skin for severe allergic asthma, nasal polyps, chronic hives and food allergy…Immunoglobulin E (Fc region)
- MepolizumabAn anti-IL-5 antibody that lowers eosinophils, used in severe eosinophilic asthma, COPD, nasal polyps, EGPA and…Interleukin-5 (IL-5)
- DupilumabAn antibody against the IL-4 receptor that blocks IL-4 and IL-13; used for atopic dermatitis, asthma, nasal polyps and…Interleukin-4 receptor alpha chain (IL-4Rα)
- BenralizumabAn antibody against the IL-5 receptor that removes eosinophils, used as add-on treatment in severe eosinophilic asthma…Interleukin-5 receptor alpha chain (IL-5Rα)
- ReslizumabAn anti-IL-5 antibody given by intravenous infusion as add-on treatment for severe eosinophilic asthma; anaphylaxis is…Interleukin-5 (IL-5)
- TezepelumabAn antibody against the epithelial alarmin TSLP, an add-on for severe asthma that also helps when eosinophils are not…Thymic stromal lymphopoietin (TSLP)
Others in the class
- Benralizumab
- Reslizumab
- Tezepelumab
Test yourself
Think of the answer, then tap the question to see it.
Which biologic binds free IgE?
Omalizumab.
Which cytokine do mepolizumab and reslizumab block, and which cell falls as a result?
IL-5; blood and airway eosinophils fall.
How does dupilumab block both IL-4 and IL-13?
It binds IL-4 receptor alpha, the chain shared by the receptors for both cytokines.
Can an asthma biologic be used to treat an acute attack?
No: they reduce future exacerbations; an attack is treated with a short-acting bronchodilator and systemic corticosteroid.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Omalizumab Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); Mepolizumab Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); Dupilumab Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025).
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Representative model, for educational purposes only.