The three major common classes of asthma controller medications include inhaled corticosteroids (ICS), beta-2-agonists and leukotriene antagonists. Among them, ICS was now suggested as the first-line therapy demonstrated in Global Initiative for Asthma guideline updated in 2017.
The response to asthma medication is markedly different even in patients with almost similar clinical manifestations. Despite the wide availability of therapeutic asthma medications and large studies supporting their efficacy, there is significant inter-personal variability in the response to each of the three major classes of asthma medications with a subgroup of patients that have limited disease control, persistent symptoms and exacerbations even under controller medications use. For example, inter-individual variability in therapeutic effectiveness to ICS in both asthma children and adults is significant, with 22 to 60% of patients being classified as non-responders.
Although many factors can contribute to variation in response to therapy effectiveness, such as higher exhaled nitric oxide, higher total eosinophil counts, higher immunoglobulin E, lower forced expiratory volume at one second (FEV1) predicted. and lower concentration of methacholine needed to produce a 20% fall in FEV1 from baseline (PC20), it is still believed that genetic variability can also play an important role. Hence asthma represents a major burden with respect to mortality, morbidity and National Health Insurance costs, searching for appropriate mediations for asthma control is imperative and investigating the effect of genetic variability on therapy response is an important step to develop personalized prescription.
