Patient description: A 53-year-old man presents with chronic HCV infection for the past 2 years. His past medical history is only significant for inguinal hernia surgery when he was 20 years old. He is on IFN (100 mg/week) plus RBV (400 mg/day) combination therapy for the past 9 months. Direct antiviral drugs were added to his treatment 6 months ago. His medical record shows previous positive HCV RNA tests as well as positive enzyme immunoassay for anti-HCV-antibodies. The recent biopsy was negative for hepatocellular carcinoma and was only remarkable for chronic inflammation compatible with a chronic viral hepatitis. There is no evidence of alcoholic liver disease, bleeding from esophageal varices, hemochromatosis, autoimmune hepatitis or metabolic liver disease. He is an alert male with no acute distress. His BP: 130/75, HR: 90/min and BMI: 27. His abdomen is soft with no ascites or tenderness. The lower extremities are normal with no edema.

Clinical trial eligibility criteria: eligible ages (years): 18.0-65.0,  Chronic Viral Hepatitis B With Delta-agent Signed Informed Consent form. 2. Males and females 18 to 65 years of age (inclusively). 3. Patients with chronic hepatitis B (HBeAg-positive or negative) and HBsAg-positive for at least 6 months prior to Screening. 4. Positive for anti-HDV antibodies for at least 6 months prior to Screening. 5. HDV RNA-positive at Screening. 6. ALT ≥ 1 x ULN and < 10 x ULN. 7. The patient agreed to use adequate method of contraception during the study, starting from the time of Informed Consent signing and until completion of the Follow-up Period  Intolerance or hypersensitivity to the active ingredient or other components of the study drug Myrcludex B. 2. Intolerance or hypersensitivity to interferons alfa, genetically engineered E.coli medications, polyethylene glycol or other components of peginterferon alfa-2a. 3. Previous treatment with Myrcludex B (patients with previous exposure to interferon are eligible). 4. Therapy with antiviral drugs for chronic viral hepatitis B with delta-agent over the previous 6 months. 5. Therapy with anti-tumour agents (including radiotherapy) or immunomodulatory medications (including systemic glucocorticoids) over the previous 6 months. 6. The following laboratory test results at Screening: 1. Hemoglobin < 100 g/L 2. Leucocytes < 3000/µL 3. Neutrophils < 1500/µL 4. Platelets < 90000/µL 5. Serum creatinine >1.5 x ULN. 7. Total bilirubin > 34.2 µM/L. Patients with higher total bilirubin may be enrolled upon consultation with the study Medical Monitor, if there is clear evidence that the elevated bilirubin is caused by Gilbert's syndrome. 8. Current or previous decompensated liver disease, including coagulopathy, hyperbilirubinemia, hepatic encephalopathy, hypoalbuminaemia, ascites, and oesophageal varices haemorrhage; Child-Pugh score of B/C or ≥6 points. 9. HCV or HIV coinfection (patients with anti-HCV antibodies and no HCV RNA at Screening are eligible). 10. Hepatocellular carcinoma. 11. Signs of drug or alcohol-induced liver disease or any other medical conditions associated with chronic liver disease (e.g. autoimmune hepatitis, hemochromatosis, thalassaemia, alcoholic hepatitis, toxic liver disease). 12. Contraindications for liver biopsy. 13. Concurrent malignancy (current diagnosed or suspected malignancy; risk of a previous malignancy recurrence). 14. Severe decompensated cardiovascular diseases, including unstable and poorly controlled conditions, over 6 months before Screening. 15. History of poorly controlled thyroid conditions or clinically significant signs of thyroid dysfunction at Screening. 16. Previous or current severe renal failure or significant renal dysfunction at Screening. 17. Previous or current chronic pulmonary disease with respiratory distortion at Screening. 18. Previous or current severe retinopathy, significant ophthalmology disorders associated with diabetes mellitus or hypertension. 19. Previous or current severe psychiatric disorders at Screening (e.g. severe depressions, suicidal attempts, severe neuroses or cognitive disorders). 20. Previous or current endocrine disorders (hypoglycaemia, hyperglycaemia, diabetes mellitus) that are not adequately controlled at Screening. 21. History of visceral organ transplantation. 22. Signs of drug and/or alcohol dependence (80 g of alcohol/day for men and 40 g of alcohol/day for women) within 1 year before Screening. 23. History of immune disorders (e.g. idiopathic thrombocytopenic purpura, lupus erythematosus, sclerodermia, severe psoriasis, rheumatoid arthritis). 24. Need for concomitant use of glucocorticoids or myelotoxic agents. 25. Participation in another clinical study within 30 days prior to enrollment into this study. 26. Pregnant or breast-feeding females. 27. Any other condition that, in the opinion of Investigator, precludes the patient from taking part in this study