• To estimate the proportions of subjects meeting the following endpoints [ Time Frame: at Week 48 ] [ Designated as safety issue: No ]
• HBV DNA < lower limit of detection [ Time Frame: at Week 48 ] [ Designated as safety issue: No ]
• Mean reduction from baseline in HBV DNA [ Time Frame: at Week 48 ] [ Designated as safety issue: No ]
• Proportion with ALT normalization (≤ 1 x ULN) [ Time Frame: at Week 48 ] [ Designated as safety issue: No ]
• Proportions with confirmed HBeAg loss and HBe seroconversion; and confirmed HBsAg loss and HBs seroconversion (for HBeAg-positive cohort only) [ Time Frame: at Week 48 ] [ Designated as safety issue: No ]
• Number and percent of subjects with adverse events (AEs), serious AEs (SAEs), laboratory abnormalities and discontinuations due to AEs. [ Time Frame: at Week 48 ] [ Designated as safety issue: Yes ]

• To estimate the proportions of subjects meeting the following endpoints at Week 48
• HBV DNA < lower limit of detection
• Mean reduction from baseline in HBV DNA
• Proportion with ALT normalization (≤ 1 x ULN)
• Proportions with confirmed HBeAg loss and HBe seroconversion; and confirmed HBsAg loss and HBs seroconversion (for HBeAg-positive cohort only)
• Number and percent of subjects with adverse events (AEs), serious AEs (SAEs), laboratory abnormalities and discontinuations due to AEs.

The purpose of this clinical research study is to develop observational clinical experience with the use of entecavir in patients who are either of Black/African-American race or of Hispanic ethnicity. (As of July 31, 2009, the recruitment for Black/African Americans was completed.)

As of July 31, 2009, the recruitment for Black/African Americans was completed.

Inclusion Criteria:

• Chronic HBV infection, with either HBeAg-positive (HBeAb-negative) or HBeAg-negative (HBeAb-positive) disease
• Black/African American Race and/or Hispanic ethnicity (As of July 31, 2009, the recruitment for Black/African Americans was completed)
• Nucleoside/tide-naive
• Males or females ≥ 16 years of age (or minimum age required in a given country)
• Compensated liver function
• HBV DNA HBe-negative > 10^4 copies/mL HBe-positive > 10^5 copies/mL
• ALT of 1.3 to 10 x ULN
• No Co-infection with HIV, HCV or HDV

Exclusion Criteria

• WOCBP who are unwilling or unable to use an acceptable method to avoid pregnancy for the entire study period and for up to 6 weeks after study medication has been discontinued
• Women who are pregnant or breastfeeding
• Women with a positive pregnancy test on enrollment or prior to study drug administration
• Evidence of decompensated cirrhosis including but not limited to: variceal bleeding; hepatic encephalopathy; or ascites requiring management with diuretics or paracentesis
• Coinfection with human immunodeficiency virus (HIV), hepatitis C virus (HCV; coinfection is defined as HCV Ab positive with detectable HCV ribonucleic acid [RNA] by PCR) or hepatitis D virus (HDV)
• Recent history of pancreatitis (resolution of any recent pancreatitis must be documented by normal lipase at least 12 weeks prior to the first dose of study medication)
• Currently abusing illegal drugs or alcohol sufficient, in the investigator's opinion, to prevent adequate compliance with study therapy or to increase the risk of hepatotoxicity or pancreatitis
• Other serious medical conditions that might preclude completion of this study or that require chronic administration of prohibited medications
• Serum creatinine > 1.5 mg/dL
• Hemoglobin < 10.0 g/dL
• Platelet count < 70,000/mm3
• Absolute neutrophil count < 1200 cells/mm3
• Serum alpha fetoprotein (AFP) level > 100 ng/mL. If the AFP level is between 21 and 100 ng/mL, it must be repeated. If the repeat AFP level is between 21 and 100 ng/mL and if ultrasonography or computerized tomography (CT) of the liver performed prior to the first dose of study medication does not demonstrate a focal lesion suggestive of carcinoma, the subject may be dosed in the study
• Known history of allergy to nucleoside analogues
• Any prior therapy with Entecavir
• Any prior or concomitant use of nucleoside or nucleotide analogue antiviral agents with activity against hepatitis B (e.g., ETV, LVD, ADV, tenofovir [TDF], emtricitabine (FTC), clevudine, telbivudine [LdT], famciclovir), or any other experimental anti-HBV antiviral agent
• Therapy with interferon, thymosin alpha or other immunostimulators within 24 weeks of enrollment (i.e., dosing) into this study
• Subjects who require chronic administration of concomitant medications which cause immunosuppression or which are associated with a high rate of nephrotoxicity or hepatotoxicity, or which affect renal excretion, should not be enrolled in this study
• Unable to tolerate oral medication
• Poor peripheral venous access
• Prisoners or subjects who are compulsorily detained (involuntarily incarcerated) for treatment of either a psychiatric or physical (e.g., infectious disease) illness must not be enrolled into this study