This is a Phase 1, single-center, randomized, double-blind, placebo-controlled, single and multiple intravenous ascending dose clinical study to evaluate the safety, tolerability, PK, immunogenicity, and biomarker characteristics of GenSci155 after a single or multiple intravenous injection in healthy Chinese adult trial participants.

Inclusion Criteria:

1.Healthy adult male or female trial participants, aged between 18 and 60 years (inclusive) Male body weight ≥ 50 kg and female body weight ≥ 45 kg; body mass index (BMI) between 19 and 28 kg/m² (inclusive) at screening 3.In good general condition as determined by medical history, physical examination, vital signs, ECG, laboratory tests, infectious diseases screening and urine drug screening with no clinically significant abnormalities as judged by the investigator .

4.Female trial participants must have a negative pregnancy test results at screening and baseline.

5.Male and female trial participants of childbearing potential must agree to use non-pharmacological contraception from screening until 3 months after the last dose. From the time of signing the ICF until 3 months after the last dose, they must have no plans for conception, sperm donation, egg donation, or egg cryopreservation. Female trial participants must have had no unprotected sexual intercourse within 14 days prior to screening.

6.Trial participants must voluntarily sign the ICF, be able to understand and comply with the requirements of this trial protocol, and complete scheduled follow-up visits in a timely manner.

Exclusion Criteria:

1. History of hypersensitivity to IGF-1 agents or their ingredients; or a history of allergic diathesis or a history of allergic diseases.
2. History or current presence of hypoglycemia, or recurrent hypoglycemic episodes.
3. Severe trauma or major surgical procedure within 12 months prior to screening that, in the investigator's judgment, may affect the safety of the trial participants or the interpretation of the study results, or planning to undergo any surgery during the trial period.
4. Blood loss or donation exceeding 400 mL within 3 months prior to screening.
5. Poor peripheral venous access; or physical condition intolerant to sampling.
6. Presence of significant active systemic or local infection within 4 weeks prior to screening.
7. Presence of tattoo, sunburn, scar or any other factors at screening that may interfere with the assessment of the injection site at the intended injection area.
8. History or current presence of any clinically significant, poorly controlled chronic disease, organ dysfunction, or malignancy that, in the investigator's judgment, may affect participant safety or study conduct.
9. Clinically significant abnormalities in chest x-ray [P-A] at screening.
10. A positive result at screening for hepatitis C virus antibody (HCV-Ab), human immunodeficiency virus antibody (HIV-Ab), treponema pallidum particle agglutination assay (AntiTP ), or hepatitis B virus (HBV) infection
11. Females who are breastfeeding during the screening period. 12.12-Lead ECG at screening showing any of the following: QTcF interval > 450 ms; or heart rate > 100 beats per minute; or any other clinically significant abnormality as determined by the investigator.

13.Any of the following laboratory abnormalities at screening:

• Aspartate aminotransferase (AST), alanine aminotransferase (ALT), or alkaline phosphatase (ALP) > upper limit of normal (ULN);

• Total bilirubin > ULN and considered clinically significant by the investigator.

• Abnormal international normalized ratio (INR) or activated partial thromboplastin time (aPTT) judged to be clinically significant by the investigator.

• Estimated glomerular filtration rate (eGFR) < lower limit of normal;

• Hematology results below the lower reference limit for any of the following and considered clinically significant by the investigator: hemoglobin, platelet count, white blood cell count, absolute lymphocyte count, or absolute neutrophil count.

• Triglyceride or low-density lipoprotein cholesterol (LDL-C) levels above the upper reference limit and considered clinically significant by the investigator.

  14.Use of any IGF-1 agents within 6 months or 5 half-lives (whichever is longer) prior to screening.

  15.Use of any prescription drugs, over-the-counter medications (including but not limited to vitamins, herbal supplements, dietary supplements, and health products), traditional Chinese medicines, or Chinese patent medicines within 14 days or 5 half-lives (whichever is longer) prior to screening or planned use during the study period.

  16.Participation in another clinical trial within 3 months or 5 half-lives (whichever is longer) prior to screening (except for trial participants who received no intervention), or current participation in any other clinical trial.

  17.Average daily cigarette consumption of ≥ 5 cigarettes within 6 months prior to screening; or unable to refrain from smoking for the duration of the study; or a positive urine cotinine test.

  18.Weekly intake of alcohol exceeding the criteria [defined as >14 units of alcohol on average per week (1 unit of alcohol = 150 mL of wine, 360 mL of beer, or 45 mL of spirits)] within 6 months prior to screening, or inability to stop drinking during the study, or a positive alcohol test.

  19.Positive urine drug screen for substances including, but not limited to: morphine, ketamine, methylenedioxymethamphetamine, methamphetamine, tetrahydrocannabinol, and cocaine.

  20.History of drug abuse; or use of so-called "soft" drugs within 3 months prior to screening; or use of so-called "hard" drugs within 1 year prior to screening.

  21.Any other condition that, in the judgment of the investigator, would make the trial participant unsuitable for participation in this clinical trial.