What is severe asthma?
Patients with severe refractory asthma have not achieved asthma control, even with high doses of ICS, usually in combination with LABAs and other maintenance treatments.
What is the most promising future treatments for severe asthma?
The most promising approaches reduce airway eosinophils in patients with severe refractory asthma and a persisting airway eosinophilia. Unfortunately, only 5% of patients with severe asthma fall into this category.
Monoclonal antibodies against IL-5 improve lung function, asthma control, reduce exacerbation risk and allow reduction or elimination of maintenance oral corticosteroids in this subset of patients.
Severe asthma - differential diagnosis and management (click to enlarge the image):
Is there are a treatment that does not depend on the cytokine profile?
Bronchial thermoplasty reduces airway smooth muscle in central airways. It may improve control and reduce exacerbations in selected patients.
The addition of the muscarinic antagonist, tiotropium also improves airflow obstruction, but its benefit on exacerbation risk is not yet established.
Other treatment approaches
Other developments being evaluated in severe refractory asthma are:
- CXCR2 antagonists in persisting neutrophilic airway inflammation
- CRTh2 antagonists (both are small molecule antagonists)
- hMabs against IL4 and IL-13
- inhaled anti-sense reduce receptor numbers and thus reduces allergen-induced airway eosinophilia. Combining different anti-sense against different targets may become a feasible treatment option
Each new treatment approaches will likely benefit only a subsets of patients. Phenotyping patients is necessary to select those likely to benefit.
Severe asthma: future treatments. O'Byrne PM, Naji N, Gauvreau GM. Clin Exp Allergy. 2012 May;42(5):706-11. doi: 10.1111/j.1365-2222.2012.03965.x.