Severe or therapy-resistant asthma is increasingly recognised as a major unmet need. A Task Force, supported by the European Respiratory Society and American Thoracic Society, reviewed the definition and provided recommendations and guidelines on the evaluation and treatment of severe asthma in children and adults.A literature review was performed, followed by discussion by an expert committee according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach for development of specific clinical recommendations.When the diagnosis of asthma is confirmed and comorbidities addressed, severe asthma is defined as asthma that requires treatment with high dose inhaled corticosteroids plus a second controller and/or systemic corticosteroids to prevent it from becoming “uncontrolled” or that remains “uncontrolled” despite this therapy. Severe asthma is a heterogeneous condition consisting of phenotypes such as eosinophilic asthma. Specific recommendations on the use of sputum eosinophil count and exhaled nitric oxide to guide therapy, as well as treatment with anti-IgE antibody, methotrexate, macrolide antibiotics, antifungal agents and bronchial thermoplasty are provided.Coordinated research efforts for improved phenotyping will provide safe and effective biomarker-driven approaches to severe asthma therapy.

There is poor agreement on definitions of different phenotypes of preschool wheezing disorders. The present Task Force proposes to use the terms episodic (viral) wheeze to describe children who wheeze intermittently and are well between episodes, and multiple-trigger wheeze for children who wheeze both during and outside discrete episodes. Investigations are only needed when in doubt about the diagnosis.Based on the limited evidence available, inhaled short-acting b 2 -agonists by metered-dose inhaler/spacer combination are recommended for symptomatic relief. Educating parents regarding causative factors and treatment is useful. Exposure to tobacco smoke should be avoided; allergen avoidance may be considered when sensitisation has been established. Maintenance treatment with inhaled corticosteroids is recommended for multiple-trigger wheeze; benefits are often small. Montelukast is recommended for the treatment of episodic (viral) wheeze and can be started when symptoms of a viral cold develop.Given the large overlap in phenotypes, and the fact that patients can move from one phenotype to another, inhaled corticosteroids and montelukast may be considered on a trial basis in almost any preschool child with recurrent wheeze, but should be discontinued if there is no clear clinical benefit.Large well-designed randomised controlled trials with clear descriptions of patients are needed to improve the present recommendations on the treatment of these common syndromes.

long-term treatment instituted, without any objective diagnostic measurements ever being made. Is there any other chronic disease for which objective diagnostic tests are readily available of which this can be said? Although the Commissioners differed in their views on the strength of evidence for diagnosis and management guided by biomarkers, particularly in children, there was a consensus that the incorporation of biomarkers into the diagnosis could only enhance the capacity to diagnose asthma responsive to ICS and lead to a paradigm shift from the current approach to diagnose the umbrella term asthma, to the diagnosis of asthma phenotypes that respond to specific treatments. New drug development Until recently we have not seen the developments in new drug discovery enjoyed by other specialty areas (table 2) 19. This area perhaps exposes the limitations of our current view of 'asthma' and airway disease most obviously. New asthma treatments are largely variants on the old; a browner inhaler, with more potent topical effects, despite increasing concerns about topical immunosuppression 103. When new treatments become available, they are widely prescribed to all comers despite being largely ineffective (Sodium Cromoglycate, Ketotifen) or effective only in subgroups of patients (Omalizumab, Mepolizumab). There has been, until recently, no concept of targeted treatment. Progress in new drug discovery has been slow, with relatively few molecules progressing from the laboratory to the clinic and a depressingly high rate of failure at the later stages of clinical development (table 2) 19. Mepolizumab, a humanised monoclonal antibody that was developed to inhibit eosinophilic airway inflammation by blocking interleukin (IL)-5, is a good example. Mepolizumab was found to be safe and effective at blocking IL-5 and reducing eosinophilic airway inflammation when tested with in vitro systems and in vivo models 104,105. A subsequent clinical trial was designed based around incorporating Mepolizumab into a step-up guideline-based paradigm 106. Within this paradigm, Mepolizumab was investigated in patients who remained symptomatic on current ICS therapy and the clinical trial focused on lung function and asthma symptoms as traditional outcome measures. Despite adequate power, this trial was unexpectedly negative. This led to much soul-searching and the near-abandonment of the drug 107. Investigators who were experienced with non-invasive measures of airway inflammation identified two important problems with this initial clinical trial: first, the heterogeneity of airway inflammation in severe asthma meant that a significant number of the trial participants would not have had eosinophilic airway inflammation and therefore would not be expected to respond; and second, the