Choice of biologics in asthma endotypes

Purpose of review The aim of this study was to highlight the phenotypes and endotypes of asthma as a tool for selection of the Food and Drug Administration approved biologic therapies. Recent findings An evolving concept of asthma has led to the identification of distinct phenotypes and endotypes in this disease. Asthma endotypes are defined as the biological mechanism and are often categorized as T2-high and T2-low based on the influence of T helper type 2 (T2) cells and type 2 cytokines, including interleukin (IL)-4, IL-5, IL-9 and IL-13. Biomarkers such as peripheral blood absolute eosinophil count, total IgE, specific IgE and fractional exhaled nitric oxide may be used as indicators of asthma endotypes and help predict response to biologic therapies. There are currently five biologic therapies approved as a treatment option for T2-high asthma: omalizumab, benralizumab, mepolizumab, reslizumab and dupilumab. Summary Here, we explore the current understandings of asthma endotypes and review their associated phenotypes. We provide practical and evidence-based guidance for clinicians considering a biologic for asthma add-on maintenance therapy.