SIM0718 Treatment of Asthma Clinical Study

Inclusion Criteria: * Age 12 to 75 years, weight ≥ 40 kg, diagnosed with asthma for at least 12 months； * Currently receiving medium- to high-dose inhaled corticosteroids (ICS) in combination with 1 or 2 control medications and have been on a stable dose for at least 28 days prior to randomization； * Pre-bronchodilator (trough) FEV1 ≤ 80% of predicted normal for adults and ≤90% of predicted normal for adolescents ； * Positive bronchodilator response within 12 months prior to randomization or during the screening period; * Asthma Control Questionnaire (ACQ-5) score ≥ 1.5; * At least one severe asthma exacerbation within 12 months prior to the screening visit and no occurrence within 28 days prior to randomization; * Based on the investigator judgment, the subject demonstrates acceptable inhaler, peak flow meter, and spirometry techniques; * Compliance with usual asthma controller use ≥ 80% based on the patient diary in 7 days prior to dosing; * Voluntarily participate in this clinical study and sign the informed consent form and be able to comply with the clinical visit schedule and study-related procedures; * Female subjects of childbearing potential who are sexually active with non-sterilized male partners, male subjects, and their female partners of childbearing potential agree to use adequate and effective contraception throughout the study; Exclusion Criteria: * Current respiratory disease that may impair lung function as judged by the investigator; * Diagnosis of helminth parasitic infection within 24 weeks prior to randomization and who have not received or have not responded to standard therapy; * Within 28 days prior to randomization, with acute or chronic infection; or have a severe viral infection; * Has a known or suspected history of immunosuppression or frequent, recurrent, or long-term infection; * History of active tuberculosis; or untreated latent tuberculosis or tuberculosis not receiving standard treatment, unless the investigator judges that the patient has been adequately treated; * People with hepatitis B, hepatitis C, or HIV infection; * History of malignancy; * Major surgery within 8 weeks prior to signing the informed; * Bronchial thermoplasty within 12 months prior to randomization; * Treatment of systemic glucocorticoid during 4 weeks prior to signing informed to randomization; * Previous use or ongoing use of systemic immunosuppressants or biologics for the treatment of autoimmune or inflammatory diseases in 8 weeks or 5 half-lives prior to randomization; * Within 16 weeks or 5 half-lives prior to randomization, received a biologic agent with the same therapeutic purpose; * Participated in an interventional clinical trial of any drug or medical device within 3 months or 5 half-lives prior to randomization; * Poor response to or intolerance to prior anti-IL-4Rα antibody therapy; * Within 3 months prior to randomization, received specific immunotherapy； * Receipt of intravenous human immunoglobulin (IVIG) or blood products within 30 days prior to randomization; * Vaccination with live(attenuated) vaccine within 30 days prior to randomization or plan to receive live (attenuated) vaccine during the study; * Are using concomitant medications or treatments that are prohibited in the protocol; * The following laboratory abnormalities occurred during the screening period: eosinophils≥1500 cells/mm3 or 1.5×109/L; Platelets≤80,000 cells/mm3 or 80×109/L; phosphocreatine kinase (CPK) ≥5 times the upper limit of normal (ULN); alanine aminotransferase (ALT) ≥3-fold ULN; aspartate aminotransferase (AST)≥ 3-fold ULN; Bilirubin ≥ 2x ULN; * History of alcohol abuse or drug abuse within 12 months prior to randomization; * Current smokers, or those who have been smoking in recent 6 months, or former smokers who have not been smoking for 6 months with a smoking history of ≥10 pack years; * Allergy to L-histidine, trehalose, or Tween 80, or history of systemic hypersensitivity to any biologic products; * Females of childbearing potential have a positive pregnancy test result during the screening period; Females planning to become pregnant or breastfeeding; * Any clinically significant examination abnormality or serious and/or uncontrolled disease that, in the opinion of the investigator, may affect the subject safety, or affect the evaluation of efficacy, or preclude the subject completion of the entire study.