A study to compare the pharmacokinetics, safety and immunogenicity of SIM0718 injection in healthy adult subjects in China

This will be a single-center, open-label, single-dose, parallel group Comparative Study.

After meeting the eligibility criteria, all eligible participants will be randomized 1:1to an experimental group (Rademikibart injection) or an Active Comparator (CBP-201 injection) as defined in the protocol. Randomization will be stratified by protocol defined body weight categories.

The study will comprise:

A Screening Period up to 28 days. One treatment period during which eligible participants will be admitted to the Clinical Unit on Day-1 to reassess their eligibility. Participants who meet eligibility criteria will be randomized to receive 300mg subcutaneous (SC) of Rademikibart injection or CBP-201 injection on Day 1. Participants will be discharged on Day 8.

The participants will return to the center for Follow-up Visits on Days 10, 12, 15, 18, 22, 29, 36 43 and 57

Inclusion Criteria:

• 1) Able to read, understand, and voluntarily sign the informed consent form.
• 2) Healthy adult male or female subjects aged 18~50 years (including the cut-off value) at screening.
• 3) The body mass index between 19 and 26 kg/m2 (including the cut-off value), and the weight of male subjects at least 50kg, and the weight of female subjects at least 45kg.
• 4) Subjects (including male subjects) and their spouses/partners have no pregnancy plan (including sperm donation and egg donation) for at least 90 days after signing the informed consent form to the last dose and voluntarily take effective non-drug contraceptive measures.
• 5)5) Able to communicate well with clinical staff and complete the trial in accordance with the protocol requirements.

Exclusion Criteria:

• 1) Subject has any clinically significant history of cardiovascular, respiratory (including asthma, bronchospasm), renal, hepatic, digestive, metabolic, endocrine, psychiatric, neurological, hematologic, or rheumatic disease, or has a psychiatric illness or disorder, or has a history of acute or chronic infections and other abnormalities that may affect safety or may affect the results of the study, as judged by the investigator.
• 2) Patients with severe infection or systemic infection within 8 weeks before administration, requiring intravenous anti-infection treatment or hospitalization due to infection; Those who have an infection (including chronic or local infection) within 7 days before administration; Those with a history of recurrent infections and underlying diseases that are prone to infection; Those who currently suffer from oral herpes or shingles.
• 3) Previous history of asthma, allergic reactions, allergic conjunctivitis, atopic dermatitis or other allergic diseases; History of significant allergy to any drug or previous serious adverse reaction to subcutaneous administration.
• 4) Known symptoms of dermatitis or skin abnormalities in and around the site of administration. The proposed injection site has skin depression, skin induration, scarring, inflammation, edema, ulcer, infection, bleeding and any other conditions that are not suitable for subcutaneous injection.
• 5) Those who have suffered from clinically significant major diseases or undergone major surgical operations within 1 month before dosing, or are expected to require major surgery during the trial.
• 6) Active tuberculosis, latent tuberculosis, or history of nontuberculous mycobacterial infection at screening Note:
• Unless there is a clear specialist document, evidence that the disease has been adequately treated, and biologics are currently acceptable (in the medical judgment of the investigator and/or infectious disease specialist);
• T-spot testing may be used to aid in the diagnosis of people with suspected tuberculosis, if needed.
• 7) Positive Treponema pallidum specific antibody (TP-Ab), hepatitis B surface antigen (HBsAg), hepatitis B core antibody (HBcAb), hepatitis C antibody (HCV-Ab), human immunodeficiency virus antigen/antibody (HIV Ag/Ab).
• 8) Abnormal vital signs at screening period or baseline as judged by the investigator to be clinically significant.
• 9) During the screening period, the laboratory examination was judged to be clinically significant by the investigator.
• 10) Female subjects who test positive for pregnancy during the screening period or baseline period or are lactating.
• 11) The 12-lead ECG showed QTcF ≥450 ms for males or QTcF ≥470 ms for females at screening, or there were other clinically significant ECG abnormalities, which the investigator judged to be inappropriate to participate in the study.
• 12) Use of prescription or over-the-counter drugs (including Chinese herbal medicines and health products) within 14 days or 5 half-lives (whichever is longer) before dosing.
• 13) Use of IL-4 drugs before screening, or treatment with biologics within 12 weeks or 5 half-lives (whichever is longer) prior to dosing.
• 14) Use of immunomodulatory drugs (including topical or systemic corticosteroids) within 4 weeks prior to the first dose.
• 15) Have received a live or live attenuated vaccine within 12 weeks prior to dosing, or will receive a live or live attenuated vaccine during the study or within 8 weeks after the last dose.
• 16) Participated in any clinical trial and received at least one trial administration within 3 months or 5 half-lives (whichever is longer) prior to dosing; Have donated blood or lost a large amount of blood (>400mL) within 3 months prior to dosing.
• 17) History of regular alcohol consumption, drinking more than 14 units of alcohol per week within 3 months prior to dosing (1 unit of alcohol = 285 mL of beer or 25 mL of spirits or 100 mL of wine); or have taken any alcohol-containing products within 48 hours before dosing; or those who have a positive alcohol breath test at the baseline visit.
• 18) Smoking more than 5 cigarettes or equivalent tobacco per day within 3 months before administration; History of drug abuse within the past five years or drug use within 3 months prior to dosing; or positive urine drug abuse screen at the screening visit/baseline visit.
• 19) Any other situation that the investigator believes may affect the subject's provision of informed consent or follow the trial protocol or judges that it is not suitable to participate in this trial, or the subject's participation in the trial may affect the trial results or their own safety.