Safety and Tolerability of VGB-R04 in Patients With Haemophilia B

Inclusion Criteria: 1. Male ≥18 years and ≤75years of age; 2. Confirmed diagnosis of hemophilia B (baseline FIX activity ≤ 2% of normal or documented history of FIX activity ≤2%); 3. At least 100 days exposure history to FIX; 4. Currently receiving FIX Prophylaxis therapy or on-demand treatment to prevent bleeding; 5. Have acceptable laboratory values: 1. Hemoglobin ≥110 g/L; 2. Platelets ≥100×10'9 cells/L; 3. AST, ALT, alkaline phosphatase ≤2×upper limit of normal (ULN) at the testing laboratory; 4. Bilirubin ≤3× ULN ; 5. Creatinine ≤1.5× ULN. 6. No measurable factor IX inhibitor as assessed by the central laboratory and have no prior history of inhibitors to factor IX protein; 7. Agree to use reliable barrier contraception until 3 consecutive samples are negative for vector sequences; 8. Able to provide informed consent and comply with the requirements of the study. Exclusion Criteria: 1. Have significant underlying liver disease within the past 6 months prior to or at Screening, including but not limited to: 1. Preexisting diagnosis of portal hypertension; 2. Splenomegaly; 3. Encephalopathy; 4. Reduction of serum albumin; 5. Evidence of significant liver fibrosis; 2. Have anti-VGB-R04 neutralizing antibody titers ≥1:5; 3. Evidence of severe infection disease, i.e., human immunodeficiency virus (HIV) infection, syphilis, tuberculosis, etc.; 4. Evidence of active hepatitis B virus infection (HBV-DNA \>103 IU/ml) or hepatitis C virus infection (HCV antigen and HCV-RNA positive); 5. Evidence of malignant tumours or those with a previous history of malignant tumours; 6. Have a history of chronic infection or other chronic diseases that the Investigator considers to constitute an unacceptable risk; 7. Any immunodeficiency; 8. Participated in a gene transfer trial within the last 52 weeks or in a clinical trial with an investigational drug within the last 4 weeks; 9. Have used glucocorticoids, immunosuppressive drugs, or antipsychotics within the last 3 months; 10. Previous history of hypersensitivity or allergic reaction to any FIX products or any immunoglobulin; 11. Unable or unwilling to comply with the schedule of visits and study assessments described in the clinical protocol; 12. Any concurrent clinically significant major disease or any other condition that, in the opinion of the Investigator, makes the subject unsuitable for participation in the study.