This study aims to evaluate the efficacy and safety of peginterferon alfa-2b plus weight-based ribavirin as initial treatment in chronic hepatitis C virus (HCV) genotype 1 patients. All patients will receive peginterferon alfa-2b plus oral ribavirin for 12 weeks. At the end of this period, quantitative PCR will be used to determine the Early Viral Response (EVR) at this point of treatment. Total treatment duration will be 48 weeks for Early Responders, 72 weeks for Slow Responders, and 12 weeks for Nonresponders.

Inclusion Criteria:

• Patients who had given their informed consent in writing.
• Adult patients, older than 18 and younger than 65 years.
• Be hepatitis C treatment-naïve patients.
• Patients should have been assessed at entry and their METAVIR score of fibrosis determined as F2, F3 or F4.
• Patients should have been diagnosed, at treatment week 0, visit 1 (V1), chronic hepatitis C determined through a positive HCV-RNA test by RT-PCR (reverse transcriptase-polymerase chain reaction) assay.
• Patients with F4 METAVIR score should have a Class A score in Child-Pugh classification, in which the following criteria should be met: Prothrombin time <=3.0 seconds; Absence of ascites; Absence of encephalopathy.
• Patients should have a compensated liver disease meeting the following minimum hematologic, biochemical and serologic criteria: Hemoglobin: >=12 g/dL in women and >=13 g/dL in men; Leukocyte count: >=3 000/mm^3; Neutrophil count: >=1 500/mm^3; Platelet count: >=80 000/mm^3; Direct bilirubin, albumin, serum creatinine: within normal ranges.
• Patients with a history of addiction should have abstained from consuming drugs for at least two years. All patients must be willing not to consume alcohol during the study.
• The investigator should confirm that sexually active women in child-bearing age are using adequate contraceptive methods.
• Neither the participating women nor the partners of participating men shall get pregnant during the study.
• Women must not get pregnant or be breast-feeding during the study period.

Exclusion Criteria:

• Having participated in any other clinical study within 30 days prior to visit at week 0 (V1) of this study treatment.
• Suffering from another liver disease other than chronic hepatitis C, such as: Hemochromatosis, alpha-1 antitrypsin deficiency, Wilson's disease, Autoimmune hepatitis , Alcoholic liver disease, Obesity-induced liver disease, Drug-induced liver disease.
• With a known coinfection with HIV or HBV.
• With evidence of decompensated liver diseases, such as history or presence of ascites, jaundice, bleeding varices, esophageal or gastric varices or hepatic encephalopathy.
• With a history of hepatocellular carcinoma (HCC).
• With any pre-existing medical condition that may interfere with patient's participation in and/or conclusion of the study, such as: Clinically significant retinal anomalies, Central nervous system (CNS) trauma or convulsive disorders, Poorly controlled diabetes mellitus, Autoimmune diseases (eg, inflammatory intestinal diseases [Crohn's disease, ulcerative colitis], rheumatoid arthritis, idiopathic thrombocytopenic purpura, systemic lupus erythematosus, autoimmune hemolytic anemia, scleroderma, severe psoriasis, clinical cryoglobulinemia with vasculitis, or symptomatic thyroid disorders), Chronic pneumopathies (eg, chronic obstructive pulmonary disease), Cardiovascular dysfunction or clinically significant electrocardiographic alterations within six months prior to visit at week 0 (eg, angina pectoris, congestive heart failure, recent heart attack, severe hypertension or significant arrhythmia), Suspected hypersensitivity to any interferon or to Ribavirin, Any organ transplantation, except corneal and hair transplantation
• With signs of suspected or active cancer or history of cancer within past five years (except for basocellular skin carcinomas receiving adequate treatment)
• With addiction, such as alcoholism (>=40 g/day), intravenous (IV) drugs and inhaled drugs. Patients who have received methadone, buprenorphine hydrochloride or butorphanol tartrate within past two years may not be admitted either.
• Suffering from any other condition that, in the investigator's opinion, would either make the patient inadequate for admission to study or affect his/her participation in and the conclusion of the study.