This study is designed to evaluate the safety of biological active dose of a new experimental drug, IL-7, in combination with standard bi-therapy in Asiatic patients with Hepatitis C chronic infection identified as non responders to the standard bi-therapy alone.

This is a Phase I/IIa inter-patient dose-escalation study assessing weekly doses of Interleukin-7 (CYT107) in Asiatic adult patients infected by virus of genotype 1 of Hepatitis C and resistant to standard treatment with Peg-Interferon and Ribavirin (bi-therapy).

The dose escalation is aimed at establishing the safety of a biologically active doses of CYT107 added to the combination therapy of pegylated interferon-alpha and ribavirin. At each dose level, study patients will receive one subcutaneous administration of CYT107 per week for a total of 4.

Groups of 3 to 6 patients will be entered at each dose level of CYT107. Three dose levels are planned.

Eligible patients initially receive bi-therapy for 6-10 weeks. Thereafter, CYT107 is added for a cycle of four weekly injections at a defined dose level while standard bi-therapy continues for 9 weeks after CYT107 treatment discontinuation. The patients are then followed on a regular basis until reaching 48 weeks after the CYT107 treatment. The duration of study is approximatively 60 weeks with 20-25 weeks of bi-therapy.

Participants will have 1 overnight hospitalization and 15 clinic visit on a period of 60 weeks.

During the visits the following may be done:

• medical history, physical examination, blood tests
• electrocardiograms (ECG)
• chest X-Ray
• liver/spleen imaging
• urine tests

Main Inclusion Criteria:

• HCV Genotype 1 infected patients
• Absence of viral response to previous treatments with pegylated interferon-alpha plus ribavirin
• Metavir ≤ F3 assessed by biopsy in the last 12 months

Main Exclusion Criteria:

• Active infection by HBV
• Infection by HIV-1 and /or HIV-2
• Apart from HCV infection, presence of active infection requiring a specific treatment or a hospitalization
• Other liver disease
• Body mass index (BMI) > 30kg/m2
• Relapse after previous response to pegylated IFN alpha and ribavirin therapy
• Previous bi-therapy with pegylated IFN alpha and ribavirin not well tolerated (in particular treatment discontinuation)
• Any history of malignancy apart from curatively treated basal cell carcinoma or in situ cervical carcinoma
• History of clinical autoimmune disease or active auto-immune disease
• History of severe asthma, presently on chronic medications
• Significant cardiac or pulmonary disease
• Inability to give informed consent