To Evaluate the Efficacy and Safety of HSK31679 in Chinese Patients With Non-Alcoholic Steatohepatitis (NASH) .

Inclusion criteria

• Must be willing to participate in the study and provide written informed consent.
• Male or female aged 18 ≤ age < 75 at the time of signing the informed consent
• Must have had prior liver biopsy within 180 days of randomization with fibrosis stage 2 to 3 and a NAS of ≥4 with at least a score of 1 in each of the lobular inflammation and ballooning degeneration.
• Must have confirmation of ≥8% liver fat content on MRI-PDFF.
• Weight changes≤5% in the 6 weeks prior to randomization.If a historical biopsy is to be used, patients must have had weight changed≤5%, too.

Exclusion criteria

• History or presence of cirrhosis，hepatic decompensation or impairment defined as presence of any of the following: history of esophageal varices, ascites, or hepatic encephalopathy, or hepatocellular carcinoma.
• Use of high dose vitamin E (>400 IU/day)，polyunsaturated fatty acid or ursodeoxycholic acid unless stable for ≥6 months prior to an eligible screening liver biopsy. Use of thiazolidinediones, sodium-glucose co-transporter 2 inhibitors or a complex oral anti-diabetic (OAD) regimen (3 or more OADs) unless stable for ≥3 months prior to an eligible screening liver biopsy.
• Use of Glucagon-like peptide 1 [GLP-1] agonist therapy (e.g.,liraglutide, semaglutide, dulaglutide and exenatide ) within 6 months prior to an eligible screening liver biopsy.
• Use of drugs that have the potential to affect thyroid hormone production and/or interfere with thyroid function.
• Potent inhibitors of CYP2C8 such as gemfibrozil and trimethoprim are prohibited. An inducer of CYP2C8, rifampicin, is prohibited.
• Use of drugs historically associated with NAFLD/NASH for 2 weeks prior to an eligible screening liver biopsy, which include, but are not limited, to the following: total parenteral nutritionamiodarone, methotrexate, systemic glucocorticoids (if use within 3 months prior to a biopsy is also not permitted), tamoxifen, tetracycline, estrogens at doses greater than those used for hormone replacement or contraception, anabolic steroids , valproic acid, and known hepatotoxins.
• Regular use of drugs historically associated with NAFLD/NASH within 12 months prior to liver biopsy (including historical biopsy), which include, but are not limited, to the following:PPAR agonists (e.g. lanifibranor, Siglitazone sodium) ，FXR agonists (e.g., obecholic acid, HTD1801)，FGF21 analogs (e.g., AP025, efruxifermin , pegozafermin(B1089-1001)) ; DGAT2 inhibitors (e.g., PF 6865571 and ION224),PDE inhibitors (e.g., ZSP1601) and other thyroid hormone receptor B agonists [e.g.,resmetirom（MGL-3196）、ASC41 and VK2809).
• Lipid-lowering therapy that did not meet the following criteria: fenofibrate, ezetimibe stable for at least 3 months before randomization and remained unchanged during study treatment, and statins stable for at least 4 weeks before randomization and remained unchanged during study treatment.
• Type 1 diabetes or uncontrolled Type 2 diabetes defined as:

• Hemoglobin A1c >9.5% at screening (patients with HbA1c >9.5% may be rescreened),
• Insulin dose adjustment >20% within 60 days prior to enrollment,
• Requirement for glucagon-like peptide analogue (unless on a stable dose ≥ 6 months prior to screening) or History of severe hypoglycemia (symptomatic hypoglycemia requiring outside assistance to regain normal neurologic status).
• Uncontrolled hypertension (either treated or untreated) defined as systolic blood pressure >160 mmHg or a diastolic blood pressure >100 mmHg at screening.
• Evidence of other forms of chronic liver disease including the following:biliary bypass, drug induced liver disease, alcoholic liver disease, autoimmune hepatitis, primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), hemohemosis, Wilson's disease, α-1 antitrypsin deficiency, bile duct obstruction, primary or metastatic liver cancer, hepatitis B, or present Hepatitis virus (HCV) infection.
• Thyroid diseases: hyperthyroidism and hypothyroidism. Thyroid peroxidase antibodies (TPOAb) or thyroglobulin antibodies (TGAb) that have been determined by the investigators to be clinically significant.
• Myocardial infarction, unstable angina, percutaneous coronary intervention, coronary artery bypass graft, or stroke within 6 months prior to screening.
• New York Heart Association class III or IV heart failure, or known left ventricular ejection fraction <30%.
• Serum ALT or AST >5 × ULN; Serum ALP≥2× ULN；eGFR<60 mL/min/1.73m2；INR>1.5× ULN；platelets < 80×109/L.
• Participation in an investigational new drug trial in the 90 days prior to randomization.
• Any other condition which, in the opinion of the Investigator, would impede compliance, hinder completion of the study, compromise the well-being of the patient, or interfere with the study outcomes.