Asthma is a heterogeneous inflammatory disease. Most patients respond to current 
standard of care, i.e., bronchodilators, inhaled glucocorticosteroids and other 
anti-inflammatory drugs, but in some adequate asthma control cannot be achieved 
with standard treatments. These difficult-to-treat patients would be the target 
population for new biological therapies. At present, omalizumab is the only 
biological agent approved for the treatment of early-onset, severe IgE-dependent 
asthma. It is safe, effective, and well tolerated. Also, discovery of asthma 
subtypes suggests new treatments. Half of patients with severe asthma have 
T-helper type 2 (Th-2) inflammation and they are expected to benefit from 
monoclonal antibody-based treatments. The efficacy of the investigational 
monoclonal antibody mepolizumab which targets IL-5 has been well documented in 
late onset non-atopic asthma with persistent eosinophilic airway inflammation. 
Anti-IL-4 and IL-13 agents (dupilumab, lebrikizumab, and tralokinumab) which 
block different Th-2 inflammatory pathways and agents targeting the Th-17 
inflammatory pathway in severe refractory asthma are under development. In 
clinical trials, these drugs reduce disease activity and improve lung function, 
asthma symptoms, and quality of life. However, studies on larger groups of 
patients are needed to confirm their safety and efficacy.