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): 18.0-999.0,  Liver Disease Hepatitis D Age 18 years or above, male or female Presence of anti-HDV in serum Presence of quantifiable HDV RNA in serum at three time pre-treatment points with a mean HDV RNA level >2 log10 above the lower limit of quantification (LLOQ) of the HDV RNA assay Demonstration of chronicity as evidenced by the presence of HDV RNA in serum for >/= 6 months, or presence of Anti-HDV antibody >/= 6months Decompensated liver disease, defined by bilirubin >4mg/dL, albumin <3.0 gm/dL, prothrombin time >2 sec prolonged, or history of bleeding esophageal varices, ascites or hepatic encephalopathy. Laboratory abnormalities that are not thought to be due to liver disease may not necessarily require exclusion. Patients with ALT levels greater than 1000 U/L (>25 times ULN) will not be enrolled but may be followed until three determinations are below this level. Patients with an absolute neutrophil count <1000/dL and platelets <75,000/dL will be excluded from the study as well Pregnancy, active breast-feeding, or inability to practice adequate contraception, in women of childbearing potential or in partners of such women. Adequate contraception is defined as vasectomy in male sexual partners of female participants, tubal ligation in women, or use of two contraceptive methods such as condoms and spermicide combination with an intrauterine device or Depo-Provera, or Norplant Significant systemic or major illnesses other than liver disease, including, but not limited to, congestive heart failure, renal failure (eGFR <50 ml/min), organ transplantation, serious psychiatric disease or depression (only if felt to be at high risk by the NIH psychiatric consultation service), or active coronary artery disease Systemic immunosuppressive therapy within the previous 2 months before enrollment Evidence of another form of liver disease in addition to viral hepatitis (for example autoimmune liver disease, primary biliary cirrhosis, primary sclerosing cholangitis, Wilson disease, alcoholic liver disease, ongoing drug induced liver disease, nonalcoholic steatohepatitis (but not steatosis), hemochromatosis, or alpha-1-antitrypsin deficiency) Active substance abuse, such as alcohol, inhaled or injection drugs within the previous year