Hepatology

Tenofovir disoproxil fumarate (DF) is highly effective for the suppression of hepatitis B virus (HBV) in chronically infected adults. This study evaluated the safety and efficacy of tenofovir DF in adolescents with chronic hepatitis B (CHB). In this double‐blind, placebo‐controlled trial, adolescents 12 to <18 years of age with CHB were randomized to tenofovir DF 300 mg (n = 52) or placebo (n = 54) once daily for 72 weeks. The primary endpoint was virologic response (HBV DNA <400 copies/mL) at week 72. One hundred six patients were enrolled; 101 patients completed 72 weeks of treatment. At baseline, 91% of patients were hepatitis B e antigen–positive and 85% had prior exposure to HBV therapy. A virologic response was observed in 89% (46/52) of patients who received tenofovir DF and 0% (0/54) of patients who received placebo (P < 0.001). Treatment response was not affected by prior HBV treatment. Furthermore, no resistance to tenofovir DF developed through week 72. Among patients with an alanine aminotransferase (ALT) level greater than the upper limit of normal at baseline, normalization of ALT occurred in 74% of patients receiving tenofovir DF and 31% of patients receiving placebo (P < 0.001). The rate of grade 3/4 adverse events was higher among patients treated with placebo (24%) than patients treated with tenofovir DF (10%). No patients met the safety endpoint of a 6% decrease in spine bone mineral density at week 72. Conclusion: Tenofovir DF therapy in HBV‐infected adolescents was well tolerated and highly effective at suppressing HBV DNA and normalizing ALT values in both treatment‐naïve adolescents and those with prior exposure to HBV therapy. (HEPATOLOGY 2012;56:2018–2026)

doi: 10.1002/hep.25875pmid: 22684948

During antiviral therapy, specific delivery of interferon‐α (IFNα) to infected cells may increase its antiviral efficacy, trigger a localized immune reaction, and reduce the side effects caused by systemic administration. Two T‐cell receptor‐like antibodies (TCR‐L) able to selectively bind hepatitis B virus (HBV)‐infected hepatocytes of chronic hepatitis B patients and recognize core (HBc18‐27) and surface (HBs183‐91) HBV epitopes associated with different human leukocyte antigen (HLA)‐A*02 alleles (A*02:01, A*02:02, A*02:07, A*02:11) were generated. Each antibody was genetically linked to two IFNα molecules to produce TCR‐L/IFNα fusion proteins. We demonstrate that the fusion proteins triggered an IFNα response preferentially on the hepatocytes presenting the correct HBV‐peptide HLA‐complex and that the mechanism of the targeted IFNα response was dependent on the specific binding of the fusion proteins to the HLA/HBV peptide complexes through the TCR‐like variable regions of the antibodies. Conclusion: TCR‐L antibodies can be used to target cytokines to HBV‐infected hepatocytes in vitro. Fusion of IFNα to TCR‐L decreased the intrinsic biological activity of IFNα but preserved the overall specificity of the protein for the cognate HBV peptide/HLA complexes. This induction of an effective IFNα response selectively in HBV‐infected cells might have a therapeutic advantage in comparison to the currently used native or pegylated IFNα. (HEPATOLOGY 2012;56:2027–2038)

doi: 10.1002/hep.25892pmid: 22706730

The ability to predict which patients are most likely to achieve a sustained virologic response (SVR) with peginterferon/ribavirin would be useful in optimizing treatment for hepatitis C virus (HCV). The objective of this large international noninterventional cohort study was to investigate the predictive value (PV) of a virologic response (VR) by weeks 2, 4, and 12 of treatment on SVR. Treatment‐naive HCV monoinfected patients (N = 7,163) age ≥18 years were prescribed peginterferon/ribavirin at the discretion of the treating physician according to country‐specific requirements in accordance with the local label. The main outcome measure was the PV of a VR (HCV RNA <50 IU/mL) by weeks 2, 4, and 12 of treatment for SVR24 (HCV RNA <50 IU/mL after 24 weeks of untreated follow‐up) by HCV genotype. The overall SVR24 rate was 49.4% (3,541/7,163; 95% confidence interval (CI): 48.3‐50.6%). SVR24 rates in patients with an HCV RNA titer <50 IU/mL by weeks 2, 4, and 12, respectively, were 66.2% (95% CI: 60.4‐71.7%), 68.4% (95% CI: 65.7‐71.0%), and 60.3% (95% CI: 58.5‐62.1%) among genotype 1 patients; 82.0% (95% CI: 76.8‐86.5%), 76.3% (95% CI: 73.3‐79.1%), and 74.2% (95% CI: 71.3‐76.9%) among genotype 2 patients; 67.3% (95% CI: 61.1‐73.1%), 67.3% (95% CI: 64.2‐70.3%), and 63.8% (95% CI: 61.0‐66.6%) among genotype 3 patients; and 59.4% (95% CI: 40.6‐76.3%), 63.3% (95% CI: 54.3‐71.6%), and 54.3% (95% CI: 47.5‐60.9%) among genotype 4 patients. The absence of a VR by week 12 had the highest negative PV across all genotypes. Conclusion: A VR by week 2 or 4 had the highest positive PV for SVR24 and differed according to HCV genotype. (HEPATOLOGY 2012;56:2039–2050)

Hepatitis B virus X protein (HBx) plays critical roles in the development of hepatocellular carcinogenesis (HCC). Yes‐associated protein (YAP), a downstream effector of the Hippo‐signaling pathway, is an important human oncogene. In the present article, we report that YAP is involved in the hepatocarcinogenesis mediated by HBx. We demonstrated that the expression of YAP was dramatically elevated in clinical HCC samples, hepatitis B virus (HBV)‐infected hepatoma HepG2.2.15 cell line, and liver cancer tissues of HBx‐transgenic mice. Meanwhile, we found that overexpression of HBx resulted in the up‐regulation of YAP in stably HBx‐transfected HepG2/H7402 hepatoma cell lines, whereas HBx RNA interference reduced YAP expression in a dose‐dependent manner in the above‐mentioned cell lines, suggesting that HBx up‐regulates YAP. Then, we investigated the mechanism underlying the up‐regulation of YAP by HBx. Luciferase reporter gene assays revealed that the promoter region of YAP regulated by HBx was located at nt −232/+115 containing cyclic adenosine monophosphate response element‐binding protein (CREB) element. Chromatin immunoprecipitation (ChIP) demonstrated that HBx was able to bind to the promoter of YAP, whereas it failed to work when CREB was silenced. Moreover, we confirmed that HBx activated the YAP promoter through CREB by electrophoretic mobility shift assay and luciferase reporter gene assays. Surprisingly, we found that YAP short interfering RNA was able to remarkably block the HBx‐enhanced growth of hepatoma cells in vivo and in vitro. Conclusion: YAP is a key driver gene in HBx‐induced hepatocarcinogenesis in a CREB‐dependent manner. YAP may serve as a novel target in HBV‐associated HCC therapy. (HEPATOLOGY 2012;56:2051–2059)

Persistent infection with hepatitis C virus (HCV) can lead to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. All current therapies of hepatitis C include interferon‐alpha (IFN‐α). Moreover, IFN‐gamma (IFN‐γ), the only type II IFN, strongly inhibits HCV replication in vitro and is the primary mediator of HCV‐specific antiviral T‐cell responses. However, for both cytokines the precise set of effector protein(s) responsible for replication inhibition is not known. The aim of this study was the identification of IFN‐α and IFN‐γ stimulated genes (ISGs) responsible for controlling HCV replication. We devised an RNA interference (RNAi)‐based “gain of function” screen and identified, in addition to known ISGs earlier reported to suppress HCV replication, several new ones with proven antiviral activity. These include IFIT3 (IFN‐induced protein with tetratricopeptide repeats 3), TRIM14 (tripartite motif containing 14), PLSCR1 (phospholipid scramblase 1), and NOS2 (nitric oxide synthase 2, inducible). All ISGs identified in this study were up‐regulated both by IFN‐α and IFN‐γ, demonstrating a substantial overlap of HCV‐specific effectors induced by either cytokine. Nevertheless, some ISGs were more specific for IFN‐α or IFN‐γ, which was most pronounced in case of PLSCR1 and NOS2 that were identified as main effectors of IFN‐γ‐mediated anti‐HCV activity. Combinatorial knockdowns of ISGs suggest additive or synergistic effects demonstrating that with either IFN, inhibition of HCV replication is caused by the combined action of multiple ISGs. Conclusion: Our study identifies a number of novel ISGs contributing to the suppression of HCV replication by type I and type II IFN. We demonstrate a substantial overlap of antiviral programs triggered by either cytokine and show that suppression of HCV replication is mediated by the concerted action of multiple effectors. (HEPATOLOGY 2012;56:2082–2093)