A protocol for a Japanese prospective cohort evaluating the features of patients with uncontrolled asthma achieving clinical remission: J-CIRCLE

Background: Increasing expectations that biologics can be used as disease-modifying agents have introduced the concept of clinical remission (CR) in managements of severe asthma. Given the clinical relevance of computed tomography (CT) and blood biomarkers, we hypothesized that further refinement of CR criteria as well as incorporation of CT and blood biomarkers as indicators for structural and biological remission (SR, BR) would enable predicting long-term disease stability in patients with severe asthma treated with biologics. Methods: This Japanese multicenter prospective observational cohort will enroll patients with severe asthma who will start a new biologic (including a change from another biologic). The enrolled patients will be longitudinally followed up for 3 years. At enrollment, patients will undergo postbronchodilator spirometry, blood tests, fractional exhaled nitric oxide, chest and sinus CT, and patient-reported outcome questionnaires. Follow-up examinations will be performed at 1, 3, 6, 12, 24, and 36 months. The rates of CR resulting from different criteria after 1 year of treatment with biologics will be compared, and factors associated with long-term disease stability after 3 years of biologic treatments will be identified. Discussion: This multicenter study in Japan will provide data that will help establish more appropriate criteria for CR, structural remission, and biological remission to predict long-term disease stability in patients with severe asthma who receive biologic therapy. Ethics and dissemination: The study was approved by the Ethics Committee of Kyoto University (No. R4419, approval date June 11th, 2024). Trial registration: The University Hospital Medical Information Network (UMIN000053771).