• Compare the safety of four oral doses of pradefovir after 48 weeks of treatment
• Select the dose of pradefovir for Phase 3 studies

• Compare the safety of four oral doses of pradefovir after 48 weeks of treatment
• Compare the antiviral activity of four oral doses of pradefovir to adefovir and dipivoxyl after 48 weeks of treatment
• Select the dose of pradefovir for Phase 3 studies
• Determine the pharacokinetic profiles of four oral doses of pradefovir

Inclusion Criteria:

• Compensated chronic HBV Infection
• No prior treatment with adefovir dipivoxil
• No interferon or lamivudine treatment for three months prior to enrollment
• HBeAg positive or negative
• HBV DNA viral load greater than 500,000 copies per mL
• ALT between 1.2 and 10 times ULN

Exclusion Criteria:

• Positive HIV, HCV, and/or HDV serology
• History of renal tubular necrosis
• Serum creatinine greater than 2.0 mg/dl
• History of organ transplant or use of immunosuppresive drugs
• Pregnant or breast-feeding females