Clinical Research Directory

Inclusion Criteria: * Age 40 and above，male or female； * COPD who meet the diagnostic criteria of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2026 ( post-bronchodilator FEV1/forced vital capacity \[FVC\] ratio \< 0.7 and post-bronchodilator FEV1% predicted ≥ 30%), and have documented history of high exacerbation risk (Group E, defined as exacerbation history of ≥ 1 moderate or severe acute exacerbation within 12 months prior to inclusion)； * Background triple therapy (ICS + LABA + LAMA) for 3 months prior to randomization with a stable dose of medication for ≥1 month prior to inclusion; Double therapy (LABA + LAMA) allowed if ICS is contraindicated； * PCR detection of Pneumocystis jirovecii in induced sputum is positive； * Informed consent Exclusion Criteria: * Allergic to TMP, SMX or sulfonamide drugs； * There are pneumonia or other infections that require long-term use of antibacterial drugs (such as tuberculosis, NTM, other fungi, etc.)； * Having used antibiotics within the previous 4 weeks prior to screening； * Experience of AECOPD events within the previous 4 weeks prior to screening; * Having a definite immunodeficiency disorder or receiving immunosuppressive therapy (such as HIV, agranulocytosis, solid organ or hematopoietic stem cell transplantation, malignant tumors, using long-term high-dose hormones \> 20mg/day prednisone equivalent for more than 4 weeks)； * Severe liver and kidney dysfunction (ALT/AST \> 3 times the upper limit of normal value, eGFR \< 60 mL/min/1.73m²)； * Pregnant, lactating women or those planning to become pregnant; * Folic acid deficiency-induced microcytic anemia; * Currently using coumarin, phenytoin, pioglitazone, repaglinide, rosiglitazone, glipizide or glibenclamide; * Currently participating in other interventional clinical studies；