Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver fibrosis stage ('Cirrhotic,' 'Transition to cirrhosis,' 'Advanced fibrosis noncirrhotic,' 'Mild/minimal fibrosis,' and 'No fibrosis') were obtained from medical records. Liver fibrosis stage was based upon previous biopsy using these five categories and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver fibrosis stage ('Cirrhotic,' 'Transition to cirrhosis,' 'Advanced fibrosis noncirrhotic,' 'Mild/minimal fibrosis,' and 'No fibrosis') were obtained from medical records. Liver fibrosis stage was based upon previous biopsy using these five categories and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver fibrosis stage ('Cirrhotic,' 'Transition to cirrhosis,' 'Advanced fibrosis noncirrhotic,' 'Mild/minimal fibrosis,' and 'No fibrosis') were obtained from medical records. Liver fibrosis stage was based upon previous biopsy using these five categories and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver fibrosis stage (Stage F0, Stage F1, Stage F2, Stage F3, or Stage F4) were obtained from medical records. Liver fibrosis stage was based upon previous biopsy using the METAVIR scoring system and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver fibrosis stage (Stage F0, Stage F1, Stage F2, Stage F3, or Stage F4) were obtained from medical records. Liver fibrosis stage was based upon previous biopsy using the METAVIR scoring system and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver fibrosis stage (Stage F0, Stage F1, Stage F2, Stage F3, or Stage F4) were obtained from medical records. Liver fibrosis stage was based upon previous biopsy using the METAVIR scoring system and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver fibrosis stage (Stage F0, Stage F1, Stage F2, Stage F3, or Stage F4) were obtained from medical records. Liver fibrosis stage was based upon previous biopsy using the METAVIR scoring system and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver elastography (FibroScan) were obtained from medical records. FibroScan values were based upon previous noninvasive assessment captured prior to treatment, if applicable. Mean FibroScan values were determined by averaging the values of all participants within each arm and expressed in kilopascals (kPa).

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver elastography (FibroScan) were obtained from medical records. FibroScan values were based upon previous noninvasive assessment captured prior to treatment, if applicable. Mean FibroScan values were determined by averaging the values of all participants within each arm and expressed in kPa.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver elastography (FibroScan) were obtained from medical records. FibroScan values were based upon previous noninvasive assessment captured prior to treatment, if applicable. Mean FibroScan values were determined by averaging the values of all participants within each arm and expressed in kPa.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver elastography (FibroScan) were obtained from medical records. FibroScan values were based upon previous noninvasive assessment captured prior to treatment, if applicable. Mean FibroScan values were determined by averaging the values of all participants within each arm and expressed in kPa.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver inflammation grade (Grade A0, Grade A1, Grade A2, or Grade A3) were obtained from medical records. Liver inflammation grade was based upon previous biopsy using the METAVIR scoring system and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver inflammation grade (Grade A0, Grade A1, Grade A2, or Grade A3) were obtained from medical records. Liver inflammation grade was based upon previous biopsy using the METAVIR scoring system and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and liver inflammation grade (Grade A0, Grade A1, Grade A2, or Grade A3) were obtained from medical records. Liver inflammation grade was based upon previous biopsy using the METAVIR scoring system and captured prior to treatment, if applicable.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including gender, were obtained from medical records and/or participant interview at the Study Visit.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including gender, were obtained from medical records and/or participant interview at the Study Visit.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including gender, were obtained from medical records and/or participant interview at the Study Visit.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including gender, were obtained from medical records and/or participant interview at the Study Visit.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including self-reported ethnic origin, were obtained from medical records and/or participant interview at the Study Visit.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including self-reported ethnic origin, were obtained from medical records and/or participant interview at the Study Visit.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including self-reported ethnic origin, were obtained from medical records and/or participant interview at the Study Visit.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including self-reported ethnic origin, were obtained from medical records and/or participant interview at the Study Visit.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including pre-treatment body weight, were obtained from medical records and/or participant interview at the Study Visit. Mean body weight was calculated by averaging the values of all participants within each arm and expressed in kilograms (kg).

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including pre-treatment body weight, were obtained from medical records and/or participant interview at the Study Visit. Mean body weight was calculated by averaging the values of all participants within each arm and expressed in kg.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including pre-treatment body weight, were obtained from medical records and/or participant interview at the Study Visit. Mean body weight was calculated by averaging the values of all participants within each arm and expressed in kg.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including pre-treatment body weight, were obtained from medical records and/or participant interview at the Study Visit. Mean body weight was calculated by averaging the values of all participants within each arm and expressed in kg.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including height and pre-treatment body weight, were obtained from medical records and/or participant interview at the Study Visit. Each participant's BMI was calculated as weight divided by height-squared, expressed in kilograms per meter-squared (kg/m^2), and mean BMI was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including height and pre-treatment body weight, were obtained from medical records and/or participant interview at the Study Visit. Each participant's BMI was calculated as weight divided by height-squared, expressed in kg/m^2, and mean BMI was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including height and pre-treatment body weight, were obtained from medical records and/or participant interview at the Study Visit. Each participant's BMI was calculated as weight divided by height-squared, expressed in kg/m^2, and mean BMI was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Demographic characteristics, including height and pre-treatment body weight, were obtained from medical records and/or participant interview at the Study Visit. Each participant's BMI was calculated as weight divided by height-squared, expressed in kg/m^2, and mean BMI was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA level was obtained from medical records. Mean HCV RNA level was calculated by averaging the values of all participants within each arm and expressed in log10 international units per milliliter (log10 IU/mL).

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA level was obtained from medical records. Mean HCV RNA level was calculated by averaging the values of all participants within each arm and expressed in log10 IU/mL.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA level was obtained from medical records. Mean HCV RNA level was calculated by averaging the values of all participants within each arm and expressed in log10 IU/mL.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA level was obtained from medical records. Mean HCV RNA level was calculated by averaging the values of all participants within each arm and expressed in log10 IU/mL.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. ALT level was obtained from medical records captured prior to treatment, if applicable. Each participant's ALT ratio was calculated as ALT level divided by the upper limit of normal (55 international units per liter [IU/L] for males and 30 IU/L for females). Mean ALT ratio was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. ALT level was obtained from medical records captured prior to treatment, if applicable. Each participant's ALT ratio was calculated as ALT level divided by the upper limit of normal (55 IU/L for males and 30 IU/L for females). Mean ALT ratio was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. ALT level was obtained from medical records captured prior to treatment, if applicable. Each participant's ALT ratio was calculated as ALT level divided by the upper limit of normal (55 IU/L for males and 30 IU/L for females). Mean ALT ratio was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. ALT level was obtained from medical records captured prior to treatment, if applicable. Each participant's ALT ratio was calculated as ALT level divided by the upper limit of normal (55 IU/L for males and 30 IU/L for females). Mean ALT ratio was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. AST level was obtained from medical records captured prior to treatment, if applicable. Each participant's AST ratio was calculated as AST level divided by the upper limit of normal (40 IU/L for males and 25 IU/L for females). Mean AST ratio was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. AST level was obtained from medical records captured prior to treatment, if applicable. Each participant's AST ratio was calculated as AST level divided by the upper limit of normal (40 IU/L for males and 25 IU/L for females). Mean AST ratio was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. AST level was obtained from medical records captured prior to treatment, if applicable. Each participant's AST ratio was calculated as AST level divided by the upper limit of normal (40 IU/L for males and 25 IU/L for females). Mean AST ratio was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. AST level was obtained from medical records captured prior to treatment, if applicable. Each participant's AST ratio was calculated as AST level divided by the upper limit of normal (40 IU/L for males and 25 IU/L for females). Mean AST ratio was calculated by averaging the values of all participants within each arm.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Platelet count was obtained from medical records captured prior to treatment, if applicable. Mean platelet count was calculated by averaging the values of all participants within each arm and expressed in 10^9 cells per liter (10^9 cells/L).

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Platelet count was obtained from medical records captured prior to treatment, if applicable. Mean platelet count was calculated by averaging the values of all participants within each arm and expressed in 10^9 cells/L.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Platelet count was obtained from medical records captured prior to treatment, if applicable. Mean platelet count was calculated by averaging the values of all participants within each arm and expressed in 10^9 cells/L.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. Platelet count was obtained from medical records captured prior to treatment, if applicable. Mean platelet count was calculated by averaging the values of all participants within each arm and expressed in 10^9 cells/L.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and geographic region of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and geographic region of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and geographic region of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and geographic region of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and geographic region of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and geographic region of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and geographic region of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and geographic region of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records, and country of study site was documented during intake/enrollment.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and virological response to prior treatment were obtained from medical records. Virological response types within the first 12 weeks of treatment included rapid virological response (RVR), complete early virological response (cEVR), and partial early virological response (pEVR). RVR was defined as an undetectable HCV RNA level within the first 4 weeks, cEVR as an undetectable level within the first 12 weeks, and pEVR as a 2-log drop from Baseline to 12 weeks. Undetectable viral loads include those below the lower limit of detection (LLOD) for the assay performed, which may vary from site to site. Response categories were mutually exclusive, meaning participants could only achieve cEVR/pEVR in the absence of RVR. Participants achieving neither RVR nor cEVR/pEVR were recorded as 'none of the above.'

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and virological response to prior treatment were obtained from medical records. Virological response types within the first 12 weeks of treatment included RVR, cEVR, and pEVR. RVR was defined as an undetectable HCV RNA level within the first 4 weeks, cEVR as an undetectable level within the first 12 weeks, and pEVR as a 2-log drop from Baseline to 12 weeks. Undetectable viral loads include those below the LLOD for the assay performed, which may vary from site to site. Response categories were mutually exclusive, meaning participants could only achieve cEVR/pEVR in the absence of RVR. Participants achieving neither RVR nor cEVR/pEVR were recorded as 'none of the above.'

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and virological response to prior treatment were obtained from medical records. Virological response types at the end of treatment included undetectable and detectable HCV RNA level. Undetectable viral loads include those below the LLOD for the assay performed, which may vary from site to site.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and virological response to prior treatment were obtained from medical records. Virological response types at the end of treatment included undetectable and detectable HCV RNA level. Undetectable viral loads include those below the LLOD for the assay performed, which may vary from site to site.

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and virological response to prior treatment were obtained from medical records. Overall virological response types included sustained virological response (SVR), relapse, and breakthrough. SVR was defined as undetectable HCV RNA level at 24 weeks post-treatment, relapse as an undetectable level at end of treatment with a detectable level at the last post-treatment measurement, and breakthrough as an undetectable level at 1 or more treatment measurements with a detectable level at end of treatment. Undetectable viral loads include those below the LLOD for the assay performed, which may vary from site to site. Response categories were mutually exclusive. Participants with detectable HCV RNA level at 12 or more treatment measurements and who did not meet SVR criteria were considered nonresponders, and those with insufficient treatment response data were recorded as 'none of the above.'

Participants underwent blood sampling at the Study Visit to determine IL28B genotype. HCV RNA genotype and virological response to prior treatment were obtained from medical records. Overall virological response types included SVR, relapse, and breakthrough. SVR was defined as undetectable HCV RNA level at 24 weeks post-treatment, relapse as an undetectable level at end of treatment with a detectable level at the last post-treatment measurement, and breakthrough as an undetectable level at 1 or more treatment measurements with a detectable level at end of treatment. Undetectable viral loads include those below the LLOD for the assay performed, which may vary from site to site. Response categories were mutually exclusive. Participants with detectable HCV RNA level at 12 or more treatment measurements and who did not meet SVR criteria were considered nonresponders, and those with insufficient treatment response data were recorded as 'none of the above.'

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype and hematology data were obtained from medical records. Participants with a history of a hemoglobin level less than 10 grams per deciliter (g/dL) or a drop of more than 3 g/dL at any time during prior treatment for CHC were recorded as 'yes' for this finding.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype and hematology data were obtained from medical records. Participants with a history of a hemoglobin level less than 10 g/dL or a drop of more than 3 g/dL at any time during prior treatment for CHC were recorded as 'yes' for this finding.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records. Past medication use was obtained from medical records and/or participant interview at the Study Visit. Participants with a history of erythropoietin use during prior treatment for CHC were recorded as 'yes' for this finding.

Participants underwent blood sampling at the Study Visit to determine ITPA genotype. HCV RNA genotype was obtained from medical records. Past medication use was obtained from medical records and/or participant interview at the Study Visit. Participants with a history of erythropoietin use during prior treatment for CHC were recorded as 'yes' for this finding.