Clinical Study of YKYY013 Injection in HBeAg-negative Chronic Hepatitis B Virus-infected Patients Treated With Nucleos(t)Ide Analogues

Who can take part

• Body Mass Index (BMI) between 18.0 to 32.0 kg/m\^2 (inclusive) and body weight equal to or over 50 kg for male and 45 kg for female
• Chronic HBV infection , with positive hepatitis B surface antigen (HBsAg) or HBV DNA for at least 6 months, and continuous stable treatment with a single nucleoside (acid) analogue (NA) for ≥ 6 months; 3）HBeAg-negative at screening; 4）100 IU/mL < HBsAg ≤ 5000 IU/mL at screening; 5）HBV DNA < 100 IU/mL at screening. 6) Medically approved contraception (e.g., intrauterine device, oral contraceptive, condom) during the trial and for 6 months after the last dose, Participants must not donate sperm or ova during the trial or for 6 months after the last dose
• The participants voluntarily participate in the study, and sign the Informed Consent Form (ICF) prior to screening

Who cannot take part

• Severe allergic reactions, non-allergic drug reactions, multiple drug allergies, or known hypersensitivity to the investigational drug or its excipients
• Major illness or major surgery (excluding minor outpatient procedures) within 3 months before screening, or planned grade 3-4 surgery during the trial
• Interferon or immunosuppressant treatment within 12 months before screening, excluding short-term (2 weeks or less) use and topical or inhaled corticosteroids
• Live vaccine within 1 month before screening
• Small interfering RNA (siRNA) drug trial within 6 months, or other investigational drug within 3 months, before screening; or planned participation in another interventional trial
• Chronic liver disease other than chronic HBV infection (e.g., severe fatty liver, alcoholic, autoimmune, or inherited metabolic liver disease)
• Current or past hepatic decompensation (e.g., esophagogastric variceal bleeding, ascites, hepatic encephalopathy)
• Liver cancer history, or imaging (ultrasound, MRI, CT) suggesting liver cancer, or alpha-fetoprotein (AFP) at least 50 ug/L
• Cardiovascular events (e.g., stroke, transient ischemic attack, myocardial infarction, unstable angina, coronary bypass surgery, percutaneous coronary intervention, heart failure hospitalization) or clinically significant valvular heart disease. Other chronic diseases considered unsuitable by the investigator (e.g., respiratory, endocrine, immune, renal, hepatic, gastrointestinal, dermatologic, hematologic, neurologic)
• Active pathological bleeding (e.g., peptic ulcer, intracranial hemorrhage) or bleeding tendency (e.g., recurrent gingival bleeding); cured disease without active or clinically significant bleeding may be enrolled at investigator discretion
• Severe infection within 1 month, or infection symptoms within 7 days, before screening
• Malignancy within 5 years, except cured resected in situ carcinoma (e.g., non-melanoma skin cancer)
• AIDS, hepatitis A, B, C, or D, or positive screening for HIV antibody, Treponema pallidum antibody, or hepatitis A, B, C, or D antibody; positive hepatitis C antibody requires HCV RNA testing, and positive HCV RNA excludes
• Any potentially hepatotoxic drug (prescription, over-the-counter, or herbal) within 14 days (or 5 half-lives, if longer) before the first dose, if judged unsuitable by the investigator; stable therapy for hypertension or diabetes is allowed
• Difficult venous access or venipuncture intolerance; history of syncope or hematophobia
• Inability to communicate or cooperate due to neurologic or psychiatric disorder or language barrier
• Fridericia-corrected QT interval (QTcF) at least 450 msec (male) or 470 msec (female); if the first ECG exceeds these limits, two more ECGs are done and the mean of three applies
• Significant laboratory abnormalities at screening, including:; Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) at least 2 times the upper limit of normal (ULN); Total bilirubin at least 2 times ULN with direct bilirubin above ULN; Serum albumin below 35 g/L; Platelets below 100 x 10\^9/L; Prothrombin time (PT) prolonged by more than 3 seconds, international normalized ratio (INR) above 1.3, or clinically significant fibrinogen abnormality; Creatinine clearance (Cockcroft-Gault) 60 mL/min or less, or clinically significant proteinuria; Poorly controlled diabetes with glycated hemoglobin (HbA1c) above 7.0%
• Liver stiffness measurement (LSM) above 9 kPa at screening, or Metavir F3 or higher on biopsy within 1 year before screening
• Clinically significant abnormalities on physical examination, vital signs, 12-lead electrocardiogram (ECG), or chest CT at screening
• Uncontrolled blood pressure at screening (systolic at least 160 mmHg or diastolic at least 100 mmHg despite treatment)
• Severe intolerance to subcutaneous injection (mild local reactions are acceptable)
• Pregnancy, lactation, or positive pregnancy test at screening or baseline
• Any scientific, compliance, or safety reason for which the investigator considers participation unsuitable