Inclusion Criteria:
1. Males or females aged between 18 and 75 years (inclusive) at screening;
2. Body mass index (BMI) ranging from 18 to 40 kg/m² (inclusive) at screening; body weight \>45 kg for female participants and \>50 kg for male participants.
3、Fall into at least 1 of the following groups (a or b):
1. sHTG i) Medical history of fasting TG level ≥500 mg/dL (≥5.65 mmol/L); ii) Mean fasting TG level ≥500 mg/dL (≥5.65 mmol/L), obtained from two separate consecutive visits during the screening period with an interval of at least 7 days and no more than 14 days; iii) Fasting LDL-C ≤130 mg/dL (≤3.37 mmol/L) at screening; or
2. HTG with ASCVD (diagnosed or at increased risk) i)Medical history of fasting TG ≥200 mg/dL (≥2.26 mmol/L) and \<500 mg/dL (\<5.65 mmol/L), with a confirmed diagnosis of ASCVD (per 2026 AHA/ACC guidelines: including acute coronary syndrome \[ACS\] (myocardial infarction \[MI\] and unstable angina), stable angina, coronary or other arterial revascularization, ischemic stroke, transient ischemic attack \[TIA\], or history of peripheral arterial disease \[PAD\]), or increased ASCVD risk (per 2026 AHA/ACC guidelines: participants with a risk ≥5% calculated using the PREVENT-ASCVD risk-calculator); ii) Mean fasting TG level ≥200 mg/dL (2.26 mmol/L) and \<500 mg/dL (5.65 mmol/L), obtained from two separate consecutive visits during the screening period with an interval of at least 7 days and no more than 14 days; iii) Fasting LDL-C ≤130 mg/dL (≤3.37 mmol/L) at screening. 4、 Prior to collection of qualifying TG levels, participants must receive standard-of-care lipid-lowering therapy in accordance with guidelines. For participants with ASCVD (diagnosed or at increased risk), therapy must include cholesterol-lowering agents (e.g., statins); 5. Participants receiving any of the following medications that may affect lipid levels must have the required stable treatment duration prior to screening and maintain stable dosing throughout the study period.
6、 Willing to follow dietary instructions and maintain a stable low-fat diet throughout the study period.
7、Participants of reproductive potential must agree to use highly effective contraceptive methods from screening until at least 9 months after the last dose of IP. Male participants must not donate sperm from screening until at least 9 months after the last dose of IP. Female participants of reproductive potential using hormonal contraception must have stable hormonal contraceptive use for more than one menstrual cycle prior to randomization.
8\. Able to understand and comply with study procedures and willing to provide written informed consent form (ICF) prior to performing any study-specific procedures.
Exclusion Criteria:
1. Current use or use within 365 days prior to screening of any hepatocyte-targeted siRNA or antisense oligonucleotide molecules (including inclisiran);
2. Known confirmed diagnosis of Familial Chylomicronemia Syndrome (FCS). For participants with suspected FCS without prior diagnosis, genetic testing results must be obtained prior to randomization to rule out FCS;
3. Uncontrolled hypertension at screening (systolic blood pressure ≥160 mmHg \*\*and/or\*\* diastolic blood pressure ≥100 mmHg);
4. Occurrence of acute pancreatitis within 12 weeks prior to screening;
5. Heart failure classified as New York Heart Association (NYHA) Class III or IV at screening;
6. Occurrence of acute coronary syndrome or cerebrovascular events (e.g., myocardial infarction, ischemic stroke) within 24 weeks prior to screening;
7. Participants who have undergone coronary artery bypass grafting, percutaneous coronary intervention, peripheral vascular revascularization, heart valve replacement or other major surgery within 24 weeks prior to screening, or who plan to undergo major surgery during the study;
8. Planned bariatric surgery or similar weight-reduction surgery from the time of signing the informed consent form through the end of the study;
9. At screening, diabetic participants with any of the following:
1. Type 1 diabetes mellitus;
2. Newly-diagnosed type 2 diabetes mellitus within 12 weeks;
3. Glycated hemoglobin (HbA1c) ≥8.5%;
4. Hospitalization events related to diabetic ketoacidosis, hyperosmolar hyperglycemic state, other diabetic complications, recurrent infection, or poor glycemic control within 24 weeks prior to screening;
10. At screening, any of the following laboratory values:
1. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \>2 × ULN;
2. Total bilirubin \>2 × ULN, except in participants with Gilbert's syndrome;
3. Estimated glomerular filtration rate (eGFR) \<60 mL/min/1.73 m² (calculated using the MDRD formula);
4. Random urine-protein-to-creatinine ratio \>500 mg/g;
5. Platelet count \<100 × 10⁹/L;
6. Clinically significant abnormalities in prothrombin time (PT), activated partial thromboplastin time (APTT), or international normalized ratio (INR) deemed by the Investigator to render the participant ineligible for the study;
7. Other clinically significant abnormalities in laboratory safety parameters deemed by the Investigator to render the participant ineligible for the study;
11. Untreated or inadequately treated hypothyroidism (i.e., thyroid-stimulating hormone \[TSH\] \>2.0 × ULN or free thyroxine \[FT4\] ≤ lower limit of normal) or hyperthyroidism, as assessed by the Investigator. Participants with well-controlled thyroid disease (stable TSH on stable therapy for at least 4 weeks) are excluded from this criterion;
12. Medical history of bleeding diathesis or coagulopathy;
13. Current concomitant nephrotic syndrome;
14. History of cirrhosis or Child-Pugh Class B or C at screening; or history of biliary obstruction;
15. Positive human immunodeficiency virus (HIV) antibody at screening; hepatitis B virus (HBV) infection (positive hepatitis B surface antigen \[HBsAg\]); active hepatitis C virus (HCV) infection (participants with positive HCV antibody must undergo further HCV RNA testing to rule out active infection); or active syphilis infection;
16. Active infection requiring systemic antiviral or antibacterial therapy within 2 weeks prior to randomization;
17. History of malignancy within 5 years prior to screening, except for adequately treated basal-cell carcinoma, cutaneous squamous-cell carcinoma, superficial bladder tumor, or carcinoma in situ of the cervix;
18. Receipt of any of the following therapies:
1. Systemic corticosteroids or anabolic steroids within 4 weeks prior to randomization or planned use during the study (except for participants with documented history of hypogonadism \[low testosterone\] on stable-dose testosterone replacement therapy for ≥16 weeks prior to randomization);
2. Plasma exchange within 4 weeks prior to randomization or planned plasma exchange during the study;
19. Blood donation of more than 200 mL within 30 days prior to screening;
20. Unwillingness to limit alcohol consumption during the study (maximum 14 units per week; 1 unit = 80 mL wine, 200 mL beer, or 25 mL of 40-proof spirits);
21. Intolerance to subcutaneous injection, or skin conditions judged by the Investigator to render subcutaneous injection inappropriate (e.g., surgical wounds, burns). Acceptable injection sites are abdomen, thigh, or upper arm;
22. Known hypersensitivity to the active ingredient or any excipient of the investigational product/placebo;
23. Participation in another investigational medicinal product trial within 30 days prior to screening (or still within 5 half-lives of the study drug, whichever is longer), or a medical device clinical trial; or plan to participate in another clinical trial during this study; or residual effects deemed present by the Investigator;
24. Medical conditions that, in the Investigator's judgment, may affect drug absorption, distribution, metabolism, or excretion, or may reduce adherence or increase participant risk; participants who may be unable to complete this study for other reasons, or other conditions rendering the participant unsuitable for study participation as judged by the Investigator.
