A Single Ascending Dose and Multiple Ascending Doses Study of SYH2082 Injection in Healthy Participants

• SYH2082 Injection (Drug): Conduct in accordance with the study protocol.
• Placebo (Drug): A subcutaneous injection in the abdomen of the corresponding dose of Placebo according to the assigned dose cohort.

Primary outcomes

• Number of Adverse Events as a measure of safety and tolerability of SYH2082 [SAD: Screening period up to day 57 MAD: Screening period up to day 85]

Secondary outcomes

• Maximum plasma concentration (Cmax) [SAD: Pre-dose at day 1 to day 57 MAD: Pre-dose at day 1 to day 85]
• Area under the concentration-time curve from time 0 to the last measurable time point (AUClast) [SAD: Pre-dose at day 1 to day 57 MAD: Pre-dose at day 1 to day 85]
• Area under the concentration time curve from time 0 to infinity (AUCinf) [SAD: Pre-dose at day 1 to day 57 MAD: Pre-dose at day 1 to day 85]
• Time to maximum concentration (Tmax) [SAD: Pre-dose at day 1 to day 57 MAD: Pre-dose at day 1 to day 85]
• Elimination half-life (t1/2) [SAD: Pre-dose at day 1 to day 57 MAD: Pre-dose at day 1 to day 85]
• Apparent volume of distribution (Vz/F) [SAD: Pre-dose at day 1 to day 57 MAD: Pre-dose at day 1 to day 85]
• Apparent clearance (CL/F) [SAD: Pre-dose at day 1 to day 57 MAD: Pre-dose at day 1 to day 85]
• Anti-SYH2082 antibodies [SAD: Pre-dose at day 1 to day 57. MAD: Pre-dose at day 1 to day 85]
• Change in fasting plasma glucose from baseline [SAD: Baseline up to Day 57]
• Change in fasting insulin from baseline [SAD: Baseline up to Day 57 MAD: Baseline up to Day 85]
• Change in C-peptide from baseline [SAD: Baseline up to Day 57 MAD: Baseline up to Day 85]
• Change in glucagon from baseline [SAD: Baseline up to Day 57]
• Change in body weight from baseline [SAD: Baseline up to Day 57 MAD: Baseline up to Day 85]
• Change in waist circumference from baseline [SAD: Baseline up to Day 57 MAD: Baseline up to Day 85]
• Corrected QT(QTc) interval [SAD: Pre-dose at day 1 to day 8 MAD: Pre-dose at day-1 to day 36]: Baseline- and placebo-corrected QTcF (ΔΔQTcF)

Sex: All, ages: 18 Years to 65 Years, accepts healthy volunteers

Inclusion Criteria:

* Fully understands the content, procedures, and possible adverse reactions of the study, and voluntarily signs the ICF before the study;
* At screening, age 18-65 years (inclusive, at the time of signing the ICF), male or female;
* At screening, body weight ≥50 kg for males and ≥45 kg for females; body mass index (BMI) between 22.0 and 40.0 kg/m2 (inclusive) for SAD part, between 25.0 and 40.0 kg/m2 for MAD part;
* Body weight change ≤5% within 3 months prior to screening (including the screening period), which shall satisfy both of the following two conditions simultaneously:

  1. Participant-recalled weights in the 3 months prior to screening are documented and used to calculate percentage weight change for the purpose of assessing the eligibility criterion (≤5%);
  2. Calibrated weights obtained at the site (e.g. Screening (D-35 to D-3 for SAD, D-35 to D-2 for MAD) and Check-in (D-2 for SAD, D-1 for MAD) visits) are compared to confirm stability between screening and check-in on the standardized, controlled scale;
* From the time of signing the ICF until 6 months after the last dose, the participant (including their partner) has no plans for childbirth and agrees to use highly effective contraceptive measures (oral hormonal contraceptives are prohibited).

Exclusion Criteria:

* Known or suspected allergy to glucagon-like peptide-1 (GLP-1) or Glucose dependent insulinotropic polypeptide (GIP) receptor agonists or any component of the investigational product; or has an allergic constitution (allergic to multiple drugs and foods);
* Abnormal results in vital signs, physical examination, laboratory tests, and ECG that are judged by the investigator to be clinically significant within the screening period. Specifically, the following conditions are not exclusionary:

  1. Systolic blood pressure (SBP) < 160 mmHg, diastolic blood pressure (DBP) < 100 mmHg;
  2. Fasting TG ≤ 5.6 mmol/L, fasting TC ≤ 7.5 mmol/L, fasting LDL-C ≤ 5 mmol/L, and abnormal fasting HDL-C;
  3. Alanine aminotransferase (ALT) < 2 × ULN, aspartate aminotransferase (AST) < 2 × ULN, gamma-glutamyl transferase (GGT) < 2.5 × ULN, and total bilirubin (TBIL) < 1.5 × ULN. Participants with values outside the normal range may be included if the abnormality is deemed benign by the investigator (e.g., Gilbert's syndrome);
* History or laboratory evidence of diabetes mellitus (type 2, type 1, or other forms of diabetes), including fasting glucose of ≥126 mg/dL (7.0 mmol/L) and/or HbA1c ≥ 6.5% within the screening period;
* With any previous episode of hypoglycemia or with screening fasting glucose < 3.9mmol/L (even on a single sample);
* With obesity due to identifiable endocrinologic, genetic or syndromic causes;
* Meets any of the following criteria within the screening period:

  1. Calcitonin ≥25 ng/L (≥ 7.31 pmol/L);
  2. Estimated glomerular filtration rate (eGFR) <80 mL/min/1.73m2
  3. Thyroid-stimulating hormone (TSH) outside the normal reference range;
  4. Fasting serum amylase and/or lipase >1.5× ULN.
* At screening, has a prolonged QT/QTc interval (QTcF >450 ms for males and QTcF>470 ms for females), or a history of risk factors for Torsades de Pointes (e.g., cardiac failure/cardiomyopathy or a family history of long QT syndrome), or is currently taking concomitant medications that prolong the QT/QTc interval;
* Positive for any of the following: Hepatitis B surface antigen, Hepatitis C virus antibody, human immunodeficiency virus antibody, or syphilis serology;
* Significant history or clinical manifestation of any metabolic, dermatological, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, neurological, respiratory, endocrine, immune or psychiatric disorder as determined by the Investigator or medical designees;
* History of severe trauma or major surgery within 3 months prior to screening, or plans to undergo surgery or any procedures requiring general anesthesia or sedation during the study period;
* History of thyroid nodules diagnosed as C-TIRADS category 3 or higher;
* Personal or family history of medullary thyroid cancer (MTC) or multiple endocrine neoplasia syndrome type 2, or a personal history of pancreatitis or gallbladder/gallstone disease;
* History of malignancy, except for non-melanoma skin cancer excised more than 1 year prior to Screening and cervical intraepithelial neoplasia that has been successfully cured more than 2 years prior to Screening;
* History of major depressive disorder; any clinically significant mental health condition (in the opinion of the principal investigator) or any mental health condition requiring medication or psychological therapy in the last 2 years;
* Lifetime history of any suicide attempts or suicide behavior according to the C-SSRS, or any suicidal ideation in the last two years according to the C-SSRS;
* Non-suicidal self-injury more than 5 years ago is permissible, if it is clear there was no suicidal intent. Participants should be excluded if any doubt;
* History of gastric emptying abnormalities (e.g., gastric outlet obstruction) or severe chronic gastrointestinal diseases (e.g., inflammatory bowel disease, active ulcer);
* History of gastrointestinal surgery that could lead to malabsorption, or long-term use of drugs that directly affect gastrointestinal motility. This includes any lifetime history of bariatric surgery or procedures (e.g., gastric banding), regardless of when they were performed;
* History of use GLP-1 or GIP receptor agonists or any drug or product that may cause weight changes and affect weight assessment considered by the investigator within 3 months prior to screening;
* Has dermatitis or other skin abnormalities (including tattoos) at or around the injection site;
* Use of any prescription drugs within 2 weeks prior to dosing or no more than 5 half-lives (whichever is longer) after the last use of the above drugs. Non-prescription drugs, herbal preparations and supplements excluded 7 days prior to dosing, and allow short term use of paracetamol and anti-inflammatory drug use within the 7 days prior to dosing, within investigator discretion. Vaccination restrictions are differentiated by vaccine type and apply from 14 days prior to the first study drug dose through 29 days after the last study drug dose:

  1. Inactivated vaccines: prohibited within 14 days prior to dosing;
  2. Live attenuated vaccines: prohibited within 28 days prior to dosing; All vaccinations are prohibited from dosing through 29 days post-dosing;
* Use of drugs that may affect glucose metabolism (e.g., systemic steroids, non-selective β-blockers, monoamine oxidase inhibitors) within 1 month prior to screening, or no more than 5 half-lives (whichever is longer) after the last use of the above drugs;
* Average weekly alcohol consumption exceeding 21 units (males) / 14 units (females) within 3 months prior to screening (1 unit ≈ 375 mL of mid-strength beer (3.5% alcohol/volume), 100 mL of wine (13.5% alcohol/volume), or 30 mL of spirits (40% alcohol/volume)), or has a positive alcohol breath test, or is unable to abstain from alcohol during the hospital stay;
* Smokes more than 10 cigarettes per day on average within 3 months prior to screening, or is unable to stop using any nicotine products during the hospital stay;
* Consumes excessive amounts of tea, coffee, and/or caffeinated beverages (average of more than 8 cups per day, 1 cup ≈ 250 mL) within 3 months prior to screening, or is unable to stop consumption during the hospital stay;
* Engaged in strenuous exercise within 48 hours prior to clinic visits, such as weightlifting, sprinting, long-distance running, cycling, swimming, or playing football;
* History of drug abuse within 6 months prior to screening, or a positive drug abuse screening test at screening and D-2/D-1;
* Has donated blood or plasma within 30 days prior to screening or had a loss of whole blood of more than 500ml within the 30 days prior to screening, or receipt of a blood transfusion within one year prior to screening;
* History of needle or blood phobia, difficulty with blood collection, or unable to tolerate intravenous blood draws;
* Has special dietary requirements and cannot adhere to the standardized diet and schedule;
* Female participants who are pregnant, lactating, or have a positive pregnancy test result at screening and D-2/D-1;
* Has received an investigational agent/device in another clinical study within 3 months or 5 half-lives prior to Screening (whichever is longer), or is currently participating in or plans to participate in another drug or medical device clinical study during the study period;
* Participants whom the investigator considers to have other factors making them unsuitable for participation in this trial.