Evaluation of 611 in Chinese Adults Patients With Moderate to Severe Chronic Obstructive Pulmonary Disease

Inclusion Criteria: 1. Able to understand and follow the protocol requirements, and give written informed consent prior to participation voluntarily in the study. 2. Male or female adults ages 40 to 85 years old when signing the informed consent. 3. Current or former smokers with a smoking history of ≥10 pack-years. 4. Documented diagnosis of COPD for at least 12 months prior to enrolment 5. Moderate-to-severe COPD. 6. Documented history of ≥ 2 moderate or ≥ 1 severe COPD exacerbations within 12 months prior to enrolment. 7. Background triple therapy (ICS + LABA + LAMA) for 3 months prior to randomization with a stable dose of medication for ≥ 1 month prior to randomization; Double therapy (LABA + LAMA) allowed if ICS is contraindicated. 8. Female subjects of reproductive age (and their male partners) and male subjects (and their female partners) must use highly effective contraception throughout the study period and for at least 3 months after the last dose. The subjects had no plans to pregnancy, donate sperm or donate egg during the whole study period and for at least 3 months after the last dose. Exclusion Criteria: 1. Presence of a known pre-existing, clinically important lung condition other than COPD. 2. A current diagnosis of asthma or history of asthma according to the Global Initiative for Asthma (GINA) guidelines or other accepted guidelines. 3. Diagnosis of α-1 anti-trypsin deficiency. 4. Presence of an active autoimmune disease. 5. Subjects who have any malignant tumors within 5 years prior to enrollment. 6. Known, pre-existing other concurrent clinically significant medical conditions that are uncontrolled. 7. Diagnosed active parasitic infection, suspected or high risk of parasitic infection. 8. Subjects who have active Hepatitis B, Hepatitis C or HIV infections as determined by positive results at Screening. 9. Known with allergic or intolerant to any biological product. 10. Any reason which, in the opinion of investigator, would prevent the subject from participating in the study.