Specialist treatments for severe asthma
Monoclonal antibodies
In patients with severe allergic or eosinophilic asthma, monoclonal antibodies improve symptoms and quality of life, and reduce exacerbations and exposure to oral corticosteroids.
Monoclonal antibodies used for asthma include omalizumab, mepolizumab and benralizumab. They are given as a subcutaneous injection; mepolizumab and benralizumab are available in an autoinjector device, which aids self-administration by the patient.
Treatment with any monoclonal antibody requires assessment by a clinician specialised in respiratory medicine or immunology, or a general physician with expertise in managing severe asthma.
For detailed information about monoclonal antibodies and their role in the Australian setting, see the Severe Asthma Toolkit.
Macrolide antibiotics
Maintenance therapy with a macrolide antibiotic (azithromycin, erythromycin, clarithromycin) is occasionally used by respiratory physicians for patients with severe asthma.
A systematic review of two studies showed that in patients with asthma who experience exacerbations despite inhaled corticosteroid and long-acting beta2 agonist (ICS+LABA) combination therapy, treatment with azithromycin reduced exacerbations1. Benefit was seen in patients with eosinophilic or noneosinophilic severe asthma.
Use of macrolide antibiotics for asthma is not approved by the Australian Therapeutic Good Administration (TGA). All patients requiring maintenance macrolide therapy should be under the care of a respiratory physician.
Allergen immunotherapy
The addition of allergen immunotherapy to standard asthma therapy may be effective in some patients with confirmed dust mite, cat or pollen allergy. Allergen immunotherapy in asthma is most often used in patients with concurrent allergic rhinitis or allergic rhinoconjunctivitis.
Subcutaneous immunotherapy is always given under medical supervision because it can cause both immediate- and slower-onset systemic reactions. These range from mild urticaria and rhinitis, through to angioedema, severe acute asthma and anaphylactic shock.
Sublingual immunotherapy should be given under medical supervision for the first dose, but subsequent doses can be taken at home. Local adverse reactions to sublingual immunotherapy occur in 20 to 30% of patients, but systemic adverse effects are rare.
Bronchial thermoplasty
Bronchial thermoplasty is a specialist invasive physical intervention. It delivers thermal energy (65°C) to the proximal airways. The mechanism of action is unclear, but may result from smooth muscle atrophy, and mechanical alterations to air flow.
Although bronchial thermoplasty has been associated with a short-term increase in symptoms and has no effect on lung function, it has also been shown to reduce severe exacerbations and hospital presentations, and improve quality of life.
At the time of writing, no controlled trials of bronchial thermoplasty have been performed in patients with severe asthma.
For more information, see the Severe Asthma Toolkit.