Novel pharmacological therapies for the treatment of bronchial asthma

Asthma has long been recognized as a chronic inflammatory disease of the airways, often in response to inhaled allergens prompting inappropriate activation of the immune response involving a range of cells including mast cells, Th2 lymphocytes and eosinophils alongside a wide range of inflammatory mediators. First-line therapy for treatment of persistent asthma involves the use of inhaled corticosteroids (ICS) in combination with inhaled β2-agonists enabling both the control of the underlying airways inflammation and a reduction of airway hyperresponsiveness. However, many patients remain symptomatic despite high-dose therapy. Therefore, there is a continued unmet clinical need to develop specifically new anti-inflammatory therapies for patients with asthma, either as an add-on therapy to ICS or as replacement monotherapies. The success of fixed dose combination inhalers containing both a bronchodilator and an anti-inflammatory drug has also led to the development of "bifunctional" drugs which are molecules specifically designed to have two distinct pharmacological actions based on distinct pharmacophores. In this review we will discuss these different pharmacological approaches under development for the treatment of bronchial asthma and the available preclinical and clinical data.