This study will assess the effcacy and safety of 610 as an adjunctive therapy in adult subjects with severe eosinophilic asthma.

This is a multicenter, randomized, double-blind, placebo-controlled study to evaluate the effcacy and safety of 610 in adults with severe eosinophilic asthma. Subjects divided into 3 groups: A group,B group and placebo group. The study is divided into screening period of 4 weeks, treatment period of 16 weeks, prolonged treatment period of 36 weeks and follow-up period of 8 weeks.

Inclusion Criteria:

• 1. Able to understand and follow the protocol requirements, and give written informed consent prior to participation voluntarily in the study.
• 2. Female and male aged 18 to 75 years.
• 3. Diagnosed with asthma for ≥12 months that meet GINA.
• 4. History of physician-diagnosed asthma requiring treatment with ICS and at least one other control medication for at least 6 months prior to screening.
• 5. Documented history of ≥ 1 moderate exacerbations within 12 months prior to screening.
• 6. Asthma Control Questionnaire question version (ACQ) score ≥1.5 at the screening visit and the randomization visit.

Exclusion Criteria:

• 1. Presence of a known pre-existing, clinically important lung condition other than Asthma.
• 2. Severe asthma exacerbation within 4 weeks prior to randomization.
• 3. Subjects with any eosinophilic diseases other than asthma.
• 4. Known, pre-existing severe or clinically significant cardiovascular disease.
• 5. known, pre-existing other concurrent clinically significant medical conditions that are uncontrolled with standard treatment.
• 6. Subjects who have active Hepatitis B, Hepatitis C or HIV infections as determined by positive results at Screening.
• 7. Subjects with allergy/intolerance to a monoclonal antibody.