The purpose of the study is to demonstrate the noninferiority of Algeron 1.5 and 2.0 μg/kg/week in combination with ribavirin compared to PegIntron in combination with ribavirin in the treatment of chronic hepatitis C, and to determine therapeutic dose of Algeron.

After 12 weeks of treatment, an assessment of treatment efficacy was performed, i.e. rates of rapid (after 4 weeks) and early (after 12 weeks) virologic responses according to serum HCV RNA level PCR data. In patients without virologic response after 12 weeks, AVT was discontinued, and they were withdrawn from the study. Patients with EVR were enrolled in a follow-up period. During the follow-up period, patients of the first and the second group will receive Algeron in the selected therapeutic dose in combination with ribavirin, patients of the third group - PegIntron in combination with ribavirin during 12 or 36 weeks (depending on a genotype of the virus), afterwards they will be followed up without therapy for 24 weeks.

Inclusion Criteria:

1. Signed informed consent to participate in the study.
2. Hepatitis С virus infection (genotypes 1а, 1b, 2, 3, 4) confirmed by a positive quantitative PCR (HCV RNA > 50 IU/ml).
3. Males and females aged from 18 to 70 years inclusive.
4. Body mass index of 18 - 30 kg/m inclusive.
5. Increased ALT level (> 40, < 400 IU/L), documented at least twice within the last 6 months.
6. Preserved protein synthetic liver function (i.e. INR < 1.7, albumin > 35 g/l).
7. No signs of hepatic encephalopathy or abdominal fluid retention according to clinical and ultrasound examination.
8. Fertile patients and their partners agree to use barrier contraception throughout the study and 7 months after its completion.

Exclusion Criteria:

1. Intolerance of IFN alpha formulations, ribavirin or any components of these drugs according to the past medical history.
2. Infection by hepatitis B virus or HIV.
3. Past history of HCV treatment with IFN alfa or pegylated IFN alfa formulations.
4. Administration of interferons and/or interferon inducing drugs for any indication within 1 month prior to the enrollment into the study.
5. Cholestatic hepatitis (conjugated bilirubin, alkaline phosphatase, ALT levels of more than 5 ULN).
6. Decompensated liver cirrhosis confirmed by laboratory findings (Child-Pugh class B, С) or ultrasound examination.
7. Any documented autoimmune diseases.
8. Hematologic (hemoglobin < 130 g/L for males and < 120 g/L for females; neutrophils < 1.5 х109/L; platelets < 90 х109/L) or biochemical abnormalities (creatinine level of more than 1.5 ULN, creatinine clearance less than 50 mL/min).
9. Documented diagnosis of hemoglobinopathies (e.g., thalassemia major, sickle-cell anemia).
10. Heavy depression, any other mental disorders, which in the Investigator's opinion can be contraindications for antiviral treatment.
11. Epilepsy and/or other functional disorders of the central nervous system.
12. Abnormal thyroid function (TTH level beyond the normal values).
13. Malignant neoplasms.
14. Pregnancy, lactation period.
15. Severe comorbidities (for example, severe hypertension, severe coronary heart disease, decompensated diabetes mellitus), which in the Investigator's opinion can be contraindications for antiviral treatment.
16. Documented rare hereditary diseases, such as intolerance of lactose, sucrose, fructose, lactase deficiency or glucose-galactose malabsorption.
17. Current alcohol or drug abuse, which in the Investigator's opinion can be contraindications for antiviral treatment or restrict treatment compliance.
18. Simultaneous participation in other clinical trials or prior participation in this or another clinical trial within less than 30 days after its completion.

During randomization, patients were stratified by gender, age, viral load, and HCV genotype. The mITT-analysis included all randomized patients received at least one dose of investigational products, who were not withdrawn from the study at its beginning due to serious violations of the inclusion/non-inclusion criteria.

The number of patients for the efficacy analysis was 150. 151 patients were included in the safety analysis, including 1 patient in Algeron group withdrawn at early stages due to a violation of inclusion/non-inclusion criteria [severe depression at Visit 1], who was not considered to be enrolled in the study due to serious protocol violation.