A Study of PEGASYS (Peginterferon Alfa-2a (40KD)) in Combination With Copegus (Ribavirin) in Patients With Chronic Hepatitis C (CHC) Enrolled in a Methadone Maintenance Treatment Program.

TCR is defined as the number of participants who completed the prescribed duration of the study treatment. TCR for G1 participants is defined as the number of participants who had a missing value or >= 2-log10 decrease in Hepatitis C virus-ribonucleic acid (HCV RNA) at Week 12 and completed 48 weeks of study treatment or had a < 2-log10 decrease from baseline at Week 12 and completed at least 12 weeks of study treatment. TCR for G2/ 3 participants is defined as the number of participants who completed 24 weeks of study treatment.

SVR is defined as the number of participants with undetectable HCV-RNA (< 10 international unit per milliliter [IU/mL]) at 24 weeks post treatment completion.

Virological Response Rate is defined as the number of participants with undetectable HCV-RNA (< 10 IU/mL). Treatment completion (end of treatment [EOT]) for G1 was Week 48 and for G2 or 3 was Week 24.

Biochemical response is defined as the number of participants with a normal serum alanine aminotransferase (ALT) concentration (i.e., ALT < 30 U/L). EOT for G1 was Week 48 and for G2/3 was Week 24.

BDI-II is 21-item self-report instrument to assess severity of symptoms of depression. There is a four-point scale for each item ranging from 0 to 3. Degrees of depression defined by the total BDI-II score as: minimal (0 to 13), mild (14 to 19), moderate (20 to 28), and severe depression (>= 29). Higher scores reflective of greater severity (worse outcome).

BDI-II is 21-item self-report instrument to assess severity of symptoms of depression. There is a four-point scale for each item ranging from 0 to 3. Degrees of depression defined by the total BDI-II score as: minimal (0 to 13), mild (14 to 19), moderate (20 to 28), and severe depression (>= 29). Higher scores reflective of greater severity (worse outcome).

Participants with degrees of depression as defined by the BDI-II Score were reported. BDI-II is 21-item self-report instrument to assess severity of symptoms of depression. There is a four-point scale for each item ranging from 0 to 3. Degrees of depression defined by the total BDI-II score as: minimal (0 to 13), mild (14 to 19), moderate (20 to 28), and severe depression (>= 29). Higher scores reflective of greater severity (worse outcome).

The HQLQ is a multiple-choice questionnaire includes the eight individual qualify-of-life scales of the Medical Outcomes Study 36-item Short-form Health Survey as: Social functioning (SF), role limitations due to emotional problems (RE), vitality (VT), general mental health (MH), physical functioning (PF), role limitations due to physical problems (RP), freedom from bodily pain (BP), and general health (GH). In addition, two other generic scales (positive well-being [PWB] and health distress [HD]) and two hepatitis-specific scales (limitations because of chronic hepatitis C [HLIM] and health distress because of chronic hepatitis C [HHD]) were included. Scores were scaled to a 0 to 100 range, with 0 = bad and 100 = good. A higher score indicates an improvement.

Participants with compliance to the prescribed treatment regimen for peginterferon alfa-2a and ribavirin was reported. Compliance was calculated as (total cumulative dose taken) / (total cumulative original dose prescribed for the entire study) x 100. Total treatment duration = Maximum doses of peginterferon alfa-2a and ribavirin in days / (48*7) for G1, total treatment duration = Maximum doses of peginterferon alfa-2a and ribavirin in days / (24*7) for G2/3.

Vital Signs included systolic blood pressures (SBP), diastolic blood pressures (DBP), and pulse rate (PR). Abnormal vital signs were reported as low or high abnormal. It was defined as < 85 mm Hg or > 180 mm Hg with a change from baseline of > 20%; DBP as > 110 mm Hg with a change from baseline of > 20%; and PR as < 50 bpm and > 120 bpm with a change from baseline of > 20%.

Hematology included hematocrit (fraction), hemoglobin, platelets count, Red blood cells (RBC), White blood cell (WBC), eosinophils, lymphocytes, monocytes, neutrophils, Partial Thromboplastin time (PTT), Prothrombin Time International Normalized Ratio (PT INR). Laboratory values falling outside the marked reference range as defined by Roche's "International Guideline for the Handling and Reporting of Laboratory Data", and were clinically relevant change from baseline were considered marked laboratory abnormalities. It was reported as low or high abnormal.

Laboratory values falling outside the marked reference range as defined by Roche's "International Guideline for the Handling and Reporting of Laboratory Data", and were clinically relevant change from baseline were considered marked laboratory abnormalities. It was reported as low or high abnormal.

An AE is defined as any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered to be related to the medicinal product. An SAE is any untoward medical occurrence that, at any dose, results in death, is life threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, or results in a congenital anomaly/birth defect. Reason for discontinuation was categorized as safety and non-safety, where safety reasons included abnormality of laboratory tests, AEs, and death; and non-safety reasons included insufficient therapeutic response, early improvement, violation of selection criteria at entry, other protocol violation, refused treatment, failure to return and other. Participants who discontinued the study with any reason were recorded.