Targeted therapy for severe bronchial asthma: Phenotyping of patients and algorithm for selecting a genetically engineered biological drug

Introduction . The “spot” effect of immunobiological drugs necessitates patients' selection based on pathogenetic mechanisms of the disease to ensure therapy effectiveness. Aim . To determine characteristics of T2-asthma main phenotypes and develop an algorithm for selecting a first- and second-line biologics. Materials and methods . Being retrospective and prospective in nature the research was directed at adult patients with severe asthma who received target therapy and were included in the registry of Sverdlovsk region. Cluster analysis made it possible to identify the most distinctive features of allergic, nonallergic eosinophilic and mixed SA. Pathogenetic mechanisms of T2 inflammation determined the choice of first-and-second-line biologics. Results . Allergic phenotype is characterized by existence of allergy and first appearance of asthma before the age of 18, satellite allergic rhinitis and the Phadiatop test result ≥ 1,53 PAU/L. The features of non-allergic eosinophilic asthma are as follows: asthma first appearance at the age of 32 and older, eosinophilia ≥ 150 cells/gl, absence of allergy, satellite chronic rhinosinusitis polyposa (CRSP) and NSAIDs intolerance. The features of the mixed asthma are as follows: first appearance at the age of ≥ 18 and < 32 years old, allergy in combination with eosinophilia ≥ 300 cells/gl, AR and a positive Phadiatop allergy test result, CRSP and NSAIDs intolerance. It is the allergic phenotype of SA when preference should be given to anti-IgE drug. Dealing with non-allergic phenotype of SA one should consider anti-IL5 biologics more preferable. Taking into consideration Th2 and ILC2 ways in action mechanism it is possible to affirm that anti-IL4R therapy is effective in mixed asthma. Conclusions . In real clinical practice the initial phenotyping of SA facilitates the correct choice of a first- and second-line targeted drug.