Fractured Exhaled Nitric Oxide and Biologic Therapies for Paediatric Asthma

Abstract Bronchial asthma is the most frequently diagnosed chronic respiratory disease in children. Treatment approaches should aim to achieve the disease control, reduce limiting symptoms, and improve the quality of life. Routine treatment of patients with asthma relies on assessment of symptoms and spirometry results. These diagnostic and therapeutic strategies do not consider the level of inflammation in the airways as a fundamental pathognomonic feature of the disease. The use of biomarkers is increasing in the context of efforts to better understand individual asthma pathways (asthma endotyping), with the potential for personalized treatment with innovative biologics. Elevated levels of exhaled nitric oxide (FENO) represent an indirect marker of T2 inflammation in airways. FENO is one of the few biomarkers that have been applied in routine clinical practice. High levels predict a good therapeutic response to treatment with corticosteroids and selected biologics (Omalizumab, Dupilumab, Mepolizumab, Tezepelumab), or an increased risk of asthma exacerbation. The aim of this review is to evaluate the advantages, disadvantages, and potential applications of this test in relation to new treatment options using biologics for asthma.