Preliminary studies suggest preemptive anti-HCV therapy in liver transplant recipients may enhance the rates of viral clearance, but the applicability and tolerability of preemptive therapy has not been evaluated in a contemporary cohort. In this randomized study, the safety and tolerability of preemptive standard (IFN) or pegylated (peg-IFN) interferon alfa-2b (3 MU thrice weekly or 1.5 lg/kg weekly), or IFN/peg-IFN plus ribavirin (600 mg increased to 1.0-1.2 g daily) was initiated 2-6 weeks post-transplantation and continued for a total of 48 weeks. Only 51 (41%) of 124 transplant recipients were eligible for preemptive treatment; eligible patients had lower model for end-stage liver disease (MELD) and Childs-Pugh scores pre-transplantation and were more frequently live donor transplant recipients than ineligible patients. Dose reductions and discontinuations were required in 85% and 37% of patients, respectively, and 27% experienced serious adverse events. Growth factor (GF) use (erythropoietin and GCSF) in the latter half of the study did not significantly affect the frequency of dose reductions. Only 15% of patients were able to achieve full-dose treatment during treatment. End-of-treatment and sustained virological responses were 13.6% and 9.1%, respectively, with most responders in the combination therapy group. We conclude that preemptive antiviral therapy is applicable to only a portion of transplant recipients, with 'sicker' patients less likely to be managed by this approach. Living donor liver transplant recipients were more frequently eligible for treatment than deceased donor recipients. Virological response rates are low, likely related to the poor tolerability of therapy and the lack of achievement of target drug doses. Future studies should focus on alternative dosing schedules with more aggressive use of adjuvant therapies, including GFs.
Interferon alpha, lamivudine, and adefovir are the three drugs currently approved for the treatment of chronic hepatitis B virus (HBV). There are pros and cons associated with the use of each drug. Individualization of therapy, based upon factors such as patient comorbidities, response to prior therapies, and stage of disease, is recommended. Patients with abnormal liver enzymes, indices of active viral replication (HBV DNA positive hepatitis B early antigen positive) or evidence of necroinflammatory activity on liver biopsy, and compensated liver disease are potential candidates for treatment with interferon, lamivudine, or adefovir. Patients with abnormal liver enzymes, indices of active viral replication (HBV DNA positive HB(e)Ag positive), and decompensated liver disease are candidates for treatment with lamivudine or adefovir. Consideration of liver transplantation should occur concurrently. Interferon alpha treatment results in hepatitis B surface antigen loss and sustained suppression of HBV DNA replication in 30% to 40% of treated patients. Loss of HBsAg occurs in nearly 10% of patients and a higher than expected frequency of HBsAg loss occurs long-term. The main limitation of therapy is the side effects and the need for parenteral administration. Additionally, interferon therapy is not applicable to all patient groups. Lamivudine achieves HB(e)Ag seroconversion in 15% to 20% of patients treated for 12 months, but (HBsAg) loss is rare. Reduction in HBV DNA to undetectable levels (by hybridization assay) during treatment is nearly universal, and histologic improvement is seen in about 55% of patients. The main limitation of lamivudine therapy is the development of drug resistance, which occurs in 20% of patients after 12 months and increases with duration of therapy (55% at 3 years). Adefovir achieves HB(e)Ag seroconversion in 12% of patients treated for 12 months, but HBsAg loss is rare. An average 3.5 log reduction in HBV DNA levels is and histologic improvement occurs in 50% to 60% of patients. It is effective against both wild-type and lamivudine-resistant HBV. The risk of drug resistance is low and estimated to be approximately 2% to 3% after 2 years of treatment. Several new antiviral agents are currently under evaluation in clinical trials. In addition, there are two drugs (tenofovir and emtricitabine) that have been approved for HIV infection and that have anti-HBV activity. In the future, combination therapy for chronic HBV infection can be anticipated. Utilization of two or more anti-HBV drugs would be predicted to enhance efficacy and reduce the likelihood of emergence of drug resistance.
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