Background: Transplantation for terminal hepatitis B virus (HBV) disease is aggravated by a high rate of reinfection and disease recurrence. Lamivudine, a new nucleoside analog, is a potent inhibitor of HBV synthesis, but its use may lead to the emergence of HBV-DNA polymerase mutants resistant to the drug.
Methods and results: We describe the case of a patient who developed an HBV recurrence after liver transplantation and was treated with lamivudine. An HBV-DNA breakthrough occurred 7 months after the start of therapy, and the drug was stopped after 9 months. The molecular state of HBV-DNA was analyzed, and a mutation in the YMDD (tyrosine, methionine, aspartate, aspartate) locus of HBV-DNA polymerase was identified. Nine months after the suspension of lamivudine the patient experienced a new hepatic attack accompanied by high HBV-DNA levels. Lamivudine was given again. Serum HBV-DNA levels normalized after 45 days of re-treatment, but lamivudine-resistant mutants were again the prevalent viral population after 3 months.
Conclusions: The case described suggests that retherapy with lamivudine after a first emergence of YMDD mutants is temporarily effective in recontrolling HBV synthesis but ultimately induces the accelerated reemergence of a prevalently mutant population of HBV. This emphasizes the need for combined antiviral therapy.