A Multicenter, Prospective, Observational, Non-Interventional Cohort Study Evaluating On-Treatment Predictors of Response in Subjects With HBeAg Positive and HBeAg Negative Chronic Hepatitis B Receiving Therapy With PEGASYS(R) (Peginterferon Alfa-2a 40KD)

Percentage of Participants With Hepatitis B Virus Surface Antigen Clearance

Time Frame: Up to 276 Weeks

Percentage of participants who became Hepatitis B Virus Surface Antigen (HBsAg) negative by the end of the observation period. A participant was considered to have achieved HBsAg clearance if the HBsAg measurement was reported as: (a) 'Negative' or (b) a quantitative result lower than the reported lower limit of detection. An observational period was upto 3 years post-treatment. The analysis was performed by 2 methods: Analysis A and Analysis B. For analysis A, all participants included in the analyzed population were used (participants with missing measurement for calculation of the endpoint were considered non-responders regarding the endpoint). For analysis B method, only participants in the analyzed population without missing measurements for calculation of the endpoint were used (analysis "as observed").

Predictive Values of Early on Treatment Response for Hepatitis B Surface Antigen Clearance 3 Years Post-Treatment- Hepatitis B Virus e Antigen Positive Participants

Time Frame: Up to 276 Weeks

The probability that the participant who develops an early virological/serological response would achieve Hepatitis B Surface Antigen (HBsAg) clearance 3 years post-treatment is called the positive predictive value (PPV) of the early virological/serological response. The probability that the participant who fails to develop an early virological/serological response also would fail to achieve HBsAg clearance 3 years post-treatment is called the negative predictive value (NPV) of the early virological/serological response. The positive and negative predictive values of early response at Weeks 12 and 24 on achievement of HBsAg clearance at 3 years post-treatment were examined. The following evidence of early response was explored (giving both NPV and PPV): For HBeAg positive participant, HBsAg \<1,500 International Units Per Milliliter (IU/mL) and HBsAg \<20,000 IU/mL at Weeks 12 and 24.

Predictive Values of Early on Treatment Response for Hepatitis B Surface Antigen Clearance 3 Years Post-Treatment- Hepatitis B Virus e Antigen Negative Participants

Time Frame: Up to 276 Weeks

The probability that the participant who develops an early virological/serological response would achieve HBsAg clearance 3 years post-treatment is called the PPV of the early virological/serological response. The probability that the participant who fails to develop an early virological/serological response also would fail to achieve HBsAg clearance 3 years post-treatment is called the NPV of the early virological/serological response. The positive and negative predictive values of early response at Weeks 12 and 24 on achievement of HBsAg clearance at 3 years post-treatment were examined. The following evidence of early response was explored (giving both NPV and PPV): For HBeAg negative patients, any decline in HBsAg from baseline to Week 12 and 24 and at least a 10% decline in HBsAg from baseline to Weeks 12 and 24.