To evaluate the efficacy and safety of TQC3721 Suspension for Inhalation in patients with moderate to severe Chronic obstructive pulmonary disease (COPD)

Inclusion Criteria:

• Sign informed consent before the test and fully understand the test content, process and possible adverse reactions.
• Male and female subjects aged 40 to 80 years old (including the cut-off value).
• Body mass index (BMI) in the range of 18-30kg/m2 (including the critical value)
• Subjects have no pregnancy plan and voluntarily use effective contraception for at least 1 month from screening to the last use of the study drug.
• Diagnosed as a COPD patient according to the The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2024 criteria.
• Able to conduct acceptable and reproducible lung function tests.
• COPD clinical stability within the 4 weeks prior to screening visit (V1 visit) and between V1 visit and V2 visit.
• Smoking history ≥ 10 pack years.

Exclusion Criteria:

• History of life-threatening COPD, including admission to the intensive care unit and/or the need for intubation.
• Screening for COPD acute exacerbations that require systemic hormone therapy prior to the visit.
• Screening for hospitalization history due to COPD within the first 6 months.
• Use antibiotics for respiratory tract infections within 6 weeks prior to screening or randomization visit.
• Chest computed tomography (CT) revealed clinically significant abnormalities and concluded that the abnormalities were not caused by COPD.
• Previous lung resection or lung reduction surgery.
• Pulmonary rehabilitation treatment.
• Previously received TQC3721 treatment.
• Patients who received immunotherapy within the first 4 weeks of the screening period.
• The patient has a history of diseases that are currently beyond their control.
• History or current evidence of cardiovascular disease with clinical significance.
• History of cured or untreated malignant tumors in any organ or system within the past 5 years.
• Screening for clinically significant safety laboratory test outliers determined by the researcher during the visit.
• Those who require oxygen therapy or intermittent oxygen therapy.
• Receive attenuated live vaccine within 28 days prior to randomization, inactivated vaccine within 7 days, or study.
• Planned vaccine recipients during the period.
• Individuals who have participated in any drug or medical device clinical trials prior to screening.
• Researchers believe that there are other situations that are not suitable for participation in the study.