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,  Hepatitis C male or female patients between 18 and 65 years of age; 2. female patients must be either postmenopausal, surgically sterile, or non-pregnant and non-lactating and have a negative serum pregnancy test result prior to enrollment into the study. Female patients of childbearing potential (including peri-menopausal women who have had a menstrual period within 1 year) must be using appropriate birth control during the entire duration of the study. Male patients may be either surgically sterile, abstinent, or utilizing a barrier contraceptive method. Abstinence or contraceptive regimen must be maintained during screening, the treatment period and for 6 weeks following the XTL6865 dose; 3. patient has been persistently HCV RNA-positive and remains HCV RNA-positive at screening (patient must have HCV RNA-concentrations which are at least 2 logs above the assay cut-off of 600 IU/mL) and HCV antibody (anti-HCV) positive; 4. patient is negative for human immunodeficiency virus (HIV), hepatitis delta virus (HDV), and has no evidence of chronic hepatitis B virus (HBV) infection (assessed by Hepatitis B surface antigen or HBV DNA in blood within 3 months of Day 1 of the study) or other clinical signs, symptoms, or laboratory abnormalities (e.g. amino transferases) leading to the a diagnosis of current acute Hepatitis B disease; 5. patient is in reasonably good health, as determined by the Investigator based on medical history, physical examination, vital signs, electrocardiogram (ECG), and clinical laboratory tests, except for findings related to their hepatitis C positive status. 6. subject's private physician has been informed of the subject's planned participation in the study; 7. capable of understanding and complying with the protocol, willing to reside in the study unit during the study period and to cooperate fully with the Investigator and site personnel, and must have signed the informed consent document prior to performance of any study-related procedures; 8. infected with HCV genotype 1 9. failed previous treatment for HCV infection with an approved regimen of IFN/RBV or pegylated IFN/RBV. Treatment failure includes both non-response (defined as a patient who did not experience a > 2 log decrease in HCV RNA after 12 weeks of treatment or who failed to clear virus to below the limits of detection after 24 weeks of treatment) or relapse (defined as re-emergence of detectable concentrations of HCV RNA after response to treatment). Treatment must have been discontinued at least 3 months prior to Day 1 of the study  liver transplant patients; 2. patients with diabetes and HbA1c at screening of 7% or more; 3. patients who have previously received HCV-AbXTL68; 4. women who are pregnant, lactating, or have a positive serum pregnancy test at screening or positive urine pregnancy test on Day 1 at check-in; 5. patient has hemoglobin < 11 g/dL for women and 12 g/dL for men, platelet count < 50,000 cells/mm3, bilirubin > 3 mg/dL, serum creatinine > 1.5 x normal, INR >1.5 x normal, ALT > 5 x upper limit of normal, or serum albumin < 3.0 g/dL (at screening); 6. patient has a history or evidence of advanced or decompensated liver disease, ascites, encephalopathy, bleeding esophageal varices, hematuria or proteinuria, alcohol or intravenous drug abuse (within <= 1 years), fulminant liver failure, acute hepatitis from any source, periarteritis nodosa, serum sickness, an acute infectious illness, severe psychiatric disorder (including major depression), organic brain disorder, mental retardation, or other clinical conditions or diseases which in the judgment of the Investigator would interfere with the study or confound the results; 7. patient has present active malignancy (except for superficial cancers) 8. past history of pulmonary embolus, deep vein thrombosis, or current therapy with heparin or warfarin; 9. patient has a history of pulmonary hypertension; 10. patient with hypertension that is not, in the investigator's opinion, adequately controlled by medication (DBP > 90 and SBP > 140). In order to assess PK in the fasted state, patients should be able to delay administration of prescribed anti-hypertensive medicine for several hours without anticipating undue risk of medically significant increases in blood pressure. Patient should be on a stable anti-hypertensive regime for at least 30 days prior to screening with no changes in anti-hypertensive medications. 11. patient is currently receiving antiviral therapy for HCV; 12. patient has received IFN/RBV or pegylated IFN/RBV treatment within 3 months of study entry (Day 1); 13. immunomodulatory therapy (eg, systemic corticosteroids or interferon) within 3 months of study entry (Day 1); 14. any patient who does not meet the conditions for prior and concomitant treatments described in Section 6.6 of this protocol; 15. any patient considering or scheduled to undergo any surgical procedure during the study; 16. has taken any other investigational drug during the 30 days prior to screening visit; 17. has donated or lost more than a unit of blood within 30 days prior to screening visit; 18. has any condition(s) that in the Investigator's opinion would: a) warrant from the study or b) prevent the patient from completing the study; 19. has limited mental capacity or language skills to the extent simple instructions cannot be followed or information regarding adverse events cannot be provided