Inclusion Criteria:

• Subject has completed ADF103814 and continues with adefovir dipivoxil treatment via prescription without interruption prior enrolment in this extension study.
• Availability and willingness of subject to provide written informed consent.
• Male or female; a female is eligible to enter and participate in this study if she is of:
• non-childbearing potential (i.e., physiologically incapable of becoming pregnant, including any female who is pre-menarchal or post-menopausal); or,

• child-bearing potential, has a negative serum pregnancy test at enrolment to this extension study, and agrees to one of the following:

  • Complete abstinence from intercourse throughout the study, and for a time interval after completion or premature discontinuation from the study to account for elimination of the investigational drug, (a minimum of 5 half-lives or longer if the pharmacodynamic profile of the investigational drug warrants a longer time period); or,
  • Female sterilization; or,
  • Sterilization of male partner; or,
  • Implants of levonorgestrel; or,
  • Injectable progestogen; or,
  • Oral contraceptive (combined or progestogen only); or,
  • Any intrauterine device (IUD) with published data showing that the lowest expected failure rate is less than 1% per year (not all IUDs meet this criterion); or,
  • Any other methods with published data showing that the lowest expected failure rate for that method is less than 1% per year; or,
  • Barrier method only if used in combination with any of the above acceptable methods.

Exclusion Criteria:

• Use of immunosuppressive therapy requiring use of more than 5mg of prednisolone(or equivalent) per day, immunomodulatory therapy (including interferon or thymosin) or systemic cytotoxic agents during the study.

Previous or current lamivudine or antiviral therapy with agents demonstrating potential anti-HBV activity except ongoing adefovir dipivoxil treatment (e.g., HBIg, famciclovir, emtricitabine, DAPD, LFMAU, entecavir, ganciclovir, L-dC, L-dT or any others)

Clinical signs of decompensated liver disease as indicated by any one of the following, but not limited to :

• serum bilirubin > 2 times upper limit normal range
• prothrombin time > 3 seconds prolonged above ULN
• serum albumin < 3.2g/dL
• history of ascites, variceal hemorrhage, or hepatic encephalopathy
• Child-Pugh score ≥8 Serum creatinine > 1.5mg/dL ( >130 mmol/L) Alanine aminotransferase (ALT) >10 times ULN or history of acute exacerbation leading to transient decompensation Serum Amylase and/or lipase > 2 x ULN

Inadequate haematological function defined by any of the following :

• Haemoglobin < 10g/dL,
• WBC count < 3.5 x 10^9/L
• Platelets < 80 x 10^9/L Documented evidence of active liver disease due to other causes including
• co-infection hepatitis C (HCV), patients who are anti-HCV positive and in whom HCV RNA is undetectable are considered to be HCV seropositive and will not be eligible for enrollment),
• co-infection hepatitis delta (HDV),
• co-infection HIV,
• autoimmune hepatitis (antinuclear antibody titre > 1:160)

Hepatocellular carcinoma as evidenced by one of the following:

• suspicious foci on ultrasound or radiological examination
• normal ultrasound but a history of rising serum alpha-fetoprotein
• where ultrasound is not available, serum alpha-fetoprotein > 40ng/mL Any serious or active medical or psychiatric illnesses other than hepatitis B which, in the opinion of the investigator, would interfere with patient treatment, assessment or compliance with the protocol. This would include any uncontrolled clinically significant renal, cardiac, pulmonary, vascular, neurogenic, digestive, metabolic (diabetes, thyroid disorders, adrenal disease), immunodeficiency disorders or cancer.

Active alcohol or drug abuse or history of alcohol or drug abuse considered by the investigator to be sufficient to hinder compliance with treatment, participation in the study or interpretation of results.

Planned for liver transplantation Therapy with nephrotoxic drugs (e.g., aminoglycosides, amphotericin B, vancomycin, cidofovir, foscarnet, cis-platinum, pentamidine etc.) or competitors of renal excretion (e.g., probenecid) can be expected during the course of the study.

History of hypersensitivity to nucleoside and/or nucleotide analogues. Inability to comply with study requirements as determined by the study investigator.