T2AIR: Real-World Efficacy and Safety of Biologics Targeting Type 2 Inflammation in Asthma and COPD

Chronic airway diseases, encompassing asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous disorders characterized by chronic airway inflammation, persistent airflow limitation, and/or airway hyperresponsiveness. These conditions commonly present with chronic cough, sputum production, and dyspnea. Acute exacerbations can be life-threatening and represent a leading global cause of disability and premature mortality among chronic non-communicable diseases.

Although inhaled corticosteroids (ICS) combined with long-acting bronchodilators (LABA/LAMA) form the mainstay of treatment, a substantial proportion of patients - approximately 5-10% with asthma and selected COPD patients experience severe or refractory disease. These patients suffer from recurrent exacerbations, progressive lung function decline, impaired quality of life, and serious complications associated with long-term oral corticosteroid (OCS) use, including osteoporosis and increased infection risk.

Type 2 (T2-high) inflammation, driven by eosinophil activation and the IL-4/IL-5/IL-13 signaling pathways, plays a central role in the pathogenesis of most severe asthma cases and a significant subset of COPD patients. In recent years, biologics targeting key mediators of Type 2 inflammation - including IgE, IL-5/IL-5Rα, IL-4Rα, and thymic stromal lymphopoietin (TSLP) - have emerged as precision therapeutic options for patients inadequately controlled on standard therapy.

The six biologics evaluated in this study are:

• Omalizumab (anti-IgE monoclonal antibody)
• Mepolizumab (anti-IL-5 monoclonal antibody)
• Benralizumab (anti-IL-5Rα monoclonal antibody)
• Dupilumab (anti-IL-4Rα monoclonal antibody, blocking IL-4/IL-13 signaling)
• Tezepelumab (anti-TSLP monoclonal antibody, effective in both T2-high and T2-low phenotypes)
• Depemokimab (ultra-long-acting anti-IL-5 Fc-fusion protein enabling twice-yearly dosing) Current international guidelines (GINA 2026 and GOLD 2026) recommend these Type 2-targeted biologics as add-on therapy for moderate-to-severe patients with poor control despite optimized standard care, with selection often guided by biomarkers such as blood eosinophils (EOS) and fractional exhaled nitric oxide (FeNO). While these agents have demonstrated efficacy in randomized controlled trials (RCTs) for severe asthma and eosinophilic COPD, robust real-world evidence remains limited, long-term use, diverse phenotypes, elderly patients, and those with multiple comorbidities. Moreover, data specific to Chinese populations are scarce. This prospective real-world observational study aims to address these evidence gaps.

Inclusion criteria

Subjects must meet all of the following criteria:

• Age ≥ 18 years; 2. Confirmed diagnosis of at least one of the following chronic airway diseases:

• Asthma: Diagnosed according to the 2025 GINA guidelines, with typical variable respiratory symptoms (wheeze, shortness of breath, chest tightness, or cough) and objective evidence of variable expiratory airflow limitation (positive bronchodilator reversibility test, positive bronchial provocation test, average daily PEF variability >10%, improvement in lung function after ICS treatment, or significant variability in lung function between two visits).
• Chronic Obstructive Pulmonary Disease (COPD): Diagnosed according to the 2026 GOLD guidelines, with symptoms of dyspnea, chronic cough, or sputum production, and/or history of exposure to risk factors, and post-bronchodilator FEV₁/FVC < 70%.

• Meets clinical indications for biologic therapy as judged by a respiratory or allergy specialist according to current guidelines:

• Asthma: Poor control despite optimized high-dose ICS-LABA therapy, presence of allergic or eosinophilic inflammatory biomarkers, or severe/refractory disease requiring maintenance oral corticosteroids (OCS).
• COPD: Frequent exacerbations despite triple inhaled therapy (ICS + LABA + LAMA), with blood eosinophil count (EOS) ≥ 300/μL and chronic bronchitis phenotype.

• The treating respiratory or allergy specialist has decided to initiate or switch to one of the following approved biologics targeting Type 2 inflammation, based on 2025 GINA and 2026 GOLD guidelines: omalizumab, mepolizumab, benralizumab, dupilumab, tezepelumab, or depemokimab (tezepelumab may be used in both Type 2 and non-Type 2 inflammation).

• Able and willing to provide written informed consent and commit to at least 12 months of follow-up.

Exclusion criteria

Subjects will be excluded if they meet any of the following criteria:

• Presence of severe or uncontrolled pulmonary or systemic diseases (e.g., active malignancy, autoimmune disease) or active infectious respiratory diseases (e.g., active pulmonary tuberculosis or infectious pneumonia);
• Pregnant, breastfeeding, or planning pregnancy during the study period;
• Known history of hypersensitivity or allergy to any component of the planned biologic agent;
• Expected life expectancy less than 12 months;
• Any other condition that, in the investigator's judgment, makes the subject unsuitable for participation (e.g., poor compliance or inability to complete follow-up).