Effectiveness of lamivudine in treatment of acute recurrent hepatitis B after liver transplantation

Established and emerging therapies for the treatment of viral hepatitis

Patients who are chronically infected with either hepatitis B or C viruses run the risk of developing cirrhosis and hepatocellular carcinoma in later life. Antiviral treatment offers the only means of interrupting this progression. To date, recombinant interferon alpha and the nucleos(t)ide analogues lamivudine and adefovir dipivoxil are the only licensed drugs for the treatment of chronic hepatitis B, whilst recombinant or pegylated interferons in combination with ribavirin are the ones used for chronic hepatitis C virus infections. The efficacy of these treatments, reasons for treatment failure, drug resistance and future options are discussed in the present review.

Current therapies for chronic hepatitis B virus infection

Patients who are chronically infected with the hepatitis B virus are at an increased risk of developing cirrhosis, hepatic decompensation and hepatocellular carcinoma. Therapeutic intervention offers the only means of interrupting this progression. Currently there are three licensed agents for the treatment of chronic hepatitis B virus infection. These are interferon-alpha, an immunomodulator, and two synthetic nucleos(t)ide analogs, namely lamivudine (Epivir, GlaxoSmithKline) and adefovir dipivoxil (Hepsera, Gilead Sciences). This review aims to summarize current experience with these drugs in the treatment and management of patients with chronic hepatitis B virus infection, their efficacy, and current problems of drug resistance. An outline of future treatment perspectives is also included.

Prevention of and treatment for hepatitis B virus infection after liver transplantation in the nucleoside analogues era

Post-transplant prophylaxis with hepatitis B immune globulin (HBIG) has significantly reduced hepatitis B virus (HBV) recurrence rates, but it is rather ineffective in patients with pretransplant viremia. Moreover, long-term HBIG administration is very expensive and may be associated with emergence of escape HBV mutants. Lamivudine has been widely used in the management of HBV transplant patients. Pretransplant lamivudine lowers HBV viremia, decreasing the risk of post-transplant HBV recurrence, but to try and minimize development of resistant HBV strains, it should start within the last 6 months of the anticipated transplantation timing. Preemptive post-transplant lamivudine monotherapy is associated with progressively increasing HBV recurrence rates, but combined therapy with lamivudine and HBIG at relatively low dosage is currently the most effective approach in this setting, even in HBV-DNA-positive patients, who also receive lamivudine in the pretransplant period. The most frequent therapy for post-transplant HBV recurrence is lamivudine, but the increasing resistance rates represent a rather challenging problem. Adefovir dipivoxil and entecavir are currently the most promising agents for lamivudine-resistant HBV strains. All these advances in anti-HBV therapy have made HBV liver disease an indication for liver transplantation irrespective of viral replication status, a complete turn around from 10 years ago.

Lamivudine treatment for hepatitis B reactivation in HBsAg carriers after organ transplantation: a 4-year experience

BACKGROUND

Reactivation of hepatitis B after organ transplantation in hepatitis B surface antigen (HBsAg) carriers may be fatal. In this study, we reported our experience of lamivudine treatment in HBsAg carriers who had post-transplant reactivation of hepatitis B.

METHODS

The patients were 15 men and one woman. Nine received kidney transplants, six received heart transplants, and one received a lung transplant. They developed a reactivation of hepatitis B 1-101 months (median, 14 months) after transplantation. They received lamivudine 100 mg daily on a compassionate-use basis, and had regular follow ups. The median pretreatment total serum bilirubin level was 3.0 mg/dL, and the alanine aminotransferase level was 357 U/L. Four of the 16 patients were positive for HBeAg. The serum hepatitis B virus (HBV) DNA levels were > 3000 pg/mL in 13 (81%) patients. Three were coinfected with hepatitis C virus.

RESULTS

The overall survival rate was 75%. All four fatal cases had a pretreatment total serum bilirubin level of > or = 3 mg/dL. Serum HBV-DNA soon became undetectable in 12 survivors. Of the 12 survivors, after a median treatment period of 101 weeks, a lamivudine-resistant strain with variation in the YMDD motif of the HBV polymerase gene developed in three (25%). None had significant adverse reactions to lamivudine treatment.

CONCLUSIONS

These results indicated that lamivudine is effective in the treatment of post-transplant hepatitis B reactivation, including patients with dual chronic hepatitis B and C. Early recognition of HBV reactivation and prompt lamivudine treatment are important to prevent mortality.

Overexpression of endothelin-1 in bile duct ligated rats: correlation with activation of hepatic stellate cells and portal pressure

BACKGROUND/AIMS

Hepatic stellate cells (HSC) are involved in the pathogenesis of liver fibrosis; although ET-1 is increased in cirrhosis, its pathophysiological role in fibrogenesis and portal hypertension remains controversial. The aim of this study was to investigate splanchnic hemodynamics and to correlate them with changes in ET-1 expression and HSC activation in bile duct ligated (BDL) rats.

METHODS/RESULTS

Expression of the ET-1 gene was increased early as measured by quantitative reverse transcriptase-polymerase chain reaction (6-fold 3 days after BDL) whereas ET-1 peptide measured by RIA increased significantly only in the late phase (30-fold at 28 days). There was a linear correlation between portal pressure and the amount of ET-1 in the portal vein (r = 0.66; P = 0.003), as well as between ET-1 and the volume fraction of myofibroblasts (r = 0.80, P < 10(-7)) as assessed by morphometry and immunohistochemical staining using alpha-smooth muscle actin.

CONCLUSIONS

During chronic liver injury activation of HSCs and of preproET-1 mRNA is accentuated in the early phase after BDL. The late increase in ET-1 peptide may indicate that this peptide is only secondarily involved in HSC activation. The correlation between ET-1 in portal vein and portal pressure suggests that ET-1 may play an important role in the development of portal hypertension.

Antiviral chemotherapy for the treatment of hepatitis B virus infections

Approximately 5% of the world's human population have an increased risk for developing liver cancer and cirrhosis as a direct consequence of chronic infection with the hepatitis B virus (HBV). Antiviral chemotherapy remains the only option for controlling infection in these individuals, for whom the current licensed hepatitis B vaccines provide no benefit. Interferon (IFN)-alpha has proven benefit in a well-defined group of those with hepatitis B but has made little impact on the global burden of chronic liver disease. The development of more effective chemotherapy for treatment of chronic hepatitis B infection has proven to be extremely challenging, the result of both virus- and host-dependent factors, which will be reviewed in this article. Past attempts to treat chronic hepatitis B infection using nucleoside analogues were disappointing, but more recently, several nucleoside (or nucleotide) analogues have been identified that are potent and selective inhibitors of HBV replication. These agents fall into two broad categories: (1) nucleoside/nucleotides that have modified sugar residues in either cyclic or acyclic configurations and (2) stereoisomers of nucleosides in the "unnatural" L-configuration. Of the analogues that have been used clinically, representatives of the first category are purine derivatives, e.g., adefovir dipivoxil and famciclovir, whereas representatives of the second category are pyrimidine derivatives, such as lamivudine.

Lamivudine. A review of its therapeutic potential in chronic hepatitis B

Lamivudine is a deoxycytidine analogue that is active against hepatitis B virus (HBV). In patients with chronic hepatitis B, lamivudine profoundly suppresses HBV replication. Clinically significant improvements in liver histology and biochemical parameters were obtained with lamivudine in double-blind, randomised, trials in hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B and compensated liver disease. After 52 weeks of treatment, relative to placebo (< or = 25%), significantly more Chinese (56%) or Western patients (52%) treated with lamivudine 100 mg/day had reductions of > or = 2 or more points in Knodell necro-inflammatory scores. Moreover, significantly fewer lamivudine 100 mg/day than placebo recipients had progressive fibrosis in liver biopsies (< or = 5 vs > or = 15%) and fewer lamivudine- than placebo-treated patients progressed to cirrhosis (1.8 vs 7.1%). More lamivudine 100 mg/day than placebo recipients acquired antibodies to HBeAg after 52 weeks (16 vs 4% in Chinese patients and 17 vs 6% in Western patients). ALT levels normalised in significantly more lamivudine than placebo recipients enrolled in these trials. In HBeAg-negative, HBV DNA positive patients with compensated liver disease enrolled in a double-blind, randomised study, HBV DNA levels were suppressed to below the limit of detection (< 2.5 pg/ml) and ALT levels normalised in 63% and 6% of patients treated with lamivudine 100 mg/day or placebo for 24 weeks. Clinically significant improvements in liver histology were obtained in 60% of patients treated with lamivudine for 52 weeks in this study. Lamivudine 100 mg/day for 52 weeks produced similar or significantly greater improvements in liver histology and ALT levels than 24 weeks' treatment with lamivudine plus interferon-alpha. In liver transplant candidates with chronic hepatitis B and end-stage liver disease, lamivudine 100 mg/day alone, or in combination with hepatitis B immune globulin, generally suppressed HBV replication and appeared to protect the grafted liver from reinfection. Lamivudine 100 mg/day suppressed viral replication and improved liver histology in liver transplant recipients with recurrent or de novo chronic hepatitis B. Lamivudine 300 or 600 mg/day reduced HBV replication in HIV-positive patients. The incidence of adverse events in patients with chronic hepatitis B and compensated liver disease treated with lamivudine 100 mg/day or placebo for 52 to 68 weeks was similar. 3.1- to 10-fold increases in ALT over baseline occurred in 13% of patients during treatment with lamivudine 100 mg/day or placebo for 52 weeks. Post-treatment ALT elevations were more common in lamivudine than placebo recipients; however, these generally resolved spontaneously; < or = 1.5% of lamivudine- or placebo-treated patients experienced hepatic decompensation.

CONCLUSION

Lamivudine inhibits HBV replication, reduces hepatic necro-inflammatory activity and the progression of fibrosis in patients with chronic hepatitis B, ongoing viral replication and compensated liver disease including HBeAg-negative patients. The drug also suppresses viral replication in liver transplant recipients and HIV-positive patients. Thus, lamivudine is potentially useful in a wide range of patients with chronic hepatitis B and ongoing viral replication.