Open-label pharmacokinetic drug interaction study.

Multi-center, phase 2, open-label, sequential-cohort, drug interaction study. Cohort 1 subjects (tacrolimus and adefovir dipivoxil) were enrolled first. Based on the findings in Cohort 1, a decision was made on whether to enroll subjects in Cohort 2 (cyclosporine and adefovir dipivoxil)(i.e., if no interaction was observed in Cohort 1, Cohort 2 subjects would not be enrolled). Since no pharmacokinetic interaction was observed in Cohort 1, Cohort 2 was not enrolled.

Inclusion Criteria:

• 18-65 years of age
• Greater than or equal to 6 months post-liver transplantation
• Must be on a documented stable total daily dose of tacrolimus or cyclosporine for three months.
• Must have calculated creatinine clearance greater than or equal 50 mL/min (Cockcroft-Gault method).