Treatment of hepatitis C in 2011: what can we expect?

Prevalence of interleukin-28B single nucleotide polymorphism genotypes in patients with hepatitis C infection in Isfahan, Iran

Background:

Hepatitis C infection is one of the most common causes of liver-related morbidity and mortality. Due to limited efficacy and side-effects of treatment, identification of the determinants of response to treatment is an important issue. Nowadays, genotyping of interleukin (IL)-28B is one of the strongest tests used for prediction of sustained virological response. The prevalence of IL28B genotypes varies across different ethnicities. This study presents data on IL28B single nucleotide polymorphism (SNP) (rs12979860) in a group of Iranian hepatitis C virus (HCV)-infected patients in Isfahan.

Materials and Methods:

One hundred patients already diagnosed for hepatitis C enrolled the study. Genomic DNA was extracted from whole blood samples. Specific primers were used to amplify IL28B gene (rs12979860). The rs129679860 SNP was genotyped by real-time polymerase chain reaction using TaqMan^® probes.

Results:

The mean age of patients was 33.16 years (25–42 years). Ninety-nine subjects were male and 1 was female. The frequency of HCV genotypes was as follows: Genotype 3a: 53%, genotype 1a: 42%, genotype 1b: 2%, mixed genotype (1a + 3a): 1% and 2%: Nontypable.

IL28B rs12979860 genotypes were TT in 17 patients (17%), CT in 41 patients (41%), and CC in the remaining 42 patients (42%).

Conclusion:

The prevalence of C allele is much higher in our population study than in African American HCV patients (62.5% and 40% respectively), which can explain better response to treatment in our patients.

EFFICACY OF TREATMENT WITH PEGYLATED INTERFERON AND RIBAVIRIN IN PATIENTS WITH CHRONIC HCV INFECTION “UNDER REAL LIFE“ CONDITIONS

Objective. To investigate the outcomes of combined therapy of hepatitis C (HCV) patients with peginterferon and ribavirin in ”real life” practice, to compare them with data obtained in randomized clinical trials (RCT) and to evaluate possible predictors of sustained virological response (SVR). Material and methods. The retrospective study of HCV patients routinely examined and treated in the Vilnius University Hospital Santariskiu Klinikos (2003−2009 yrs) was carried out. They had undergone the treatment with combination of peginterferon alfa and ribavirin according to the Lithuanian guide. Overall 203 patients were enrolled. SVR was evaluated in 179 patients. Results. The overall rate of SVR was 43 %: in 51,3 % of naives (genotype 1 − 38,8 %, genotype 2 – 100 %, genotype 3 − 82,6 % cases) and in 28,1 % of experienced patients (genotype 1 – 17 %, and genotype 3 – 64,3 % cases). Significant relations of SVR and HCV genotype was observed: 68,9 % having genotype1 were non-responders, whereas 80 % and 75,7 % ones with genotype 2 and 3 achieved SVR (p 0.005 and p = 0.01, respectively). The inverse relation with the age (p 0.01), degree of fibrosis (p = 0.039) and previous unsuccessful treatment was confirmed by multivariate analysis. Conclusions. Data of SVR obtained „on real life“ conditions are non unambiguous: SVR of naive and experienced patients overall and those with genotype 1 were similar or slightly lower, while for patients with genotype 3 significantly higher than results presented in clinical trials. Genotype 1, previous unsuccessful antiviral treatment, older age, and advanced fibrosis were strongest negative predictors for SVR.

HCV infection: an enigma, recent advances and new paradigms for its treatment

HCV infection is a serious human liver health problem and has infected 200 million people worldwide. Persistent HCV infection can lead to chronic hepatitis C, which is a significant risk of serious hepatic diseases such as hepatic steatosis, hepatic fibrosis and hepatocellular carcinoma. The current standard-of-care options to treat HCV infection are limited, expensive and produce side effects in infected patients that often cause termination of the therapy. Recently, the approval of direct-acting antivirals represents a major breakthrough for the improvement of treatment strategies against chronic HCV infection. Similarly, the development of more effective, safe and well-tolerated interferon therapy is opening a new era in HCV therapeutics. Moreover, a new vaccine technology has been tested in mice for its therapeutic efficacy against the most conserved regions of the HCV genome. This review article will focus on the recent advances in HCV therapeutics and discuss new paradigms to develop the most convenient drugs and treatment strategies.

Response-guided telaprevir therapy in prior relapsers? The role of bridging data from treatment-naïve and experienced subjects

The purpose of this report is to illustrate the US Food and Drug Administration's rationale for approving response-guided therapy (RGT) for telaprevir (TVR) in combination with pegylated interferon-α and ribavirin (P/R) for the treatment of adults with genotype 1 chronic hepatitis C who were prior relapsers. RGT was prospectively evaluated in two registration trials of treatment-naïve subjects. In these studies, RGT allowed subjects who achieved undetectable hepatitis C virus RNA from weeks 4 and 12, known as extended rapid virologic response (eRVR), to stop all treatments at 24 weeks. A patient without eRVR received an additional 36 weeks of P/R after 12 weeks of a TVR triple regimen (total of 48 weeks). However, RGT in prior P/R relapsers was not prospectively evaluated. Empirical cross-trial data indicated high sustained virologic response rates (>90%) in prior relapsers achieving eRVR, irrespective of P/R duration (24 or 48 weeks). Further analyses demonstrated that interferon responsiveness does not change in P/R-experienced subjects with a second round of P/R. The comparability in interferon responsiveness across treatment courses allowed us to bridge data between treatment-naïve and P/R-experienced subjects to support the approval of RGT in prior relapse subjects.

C-6 aryl substituted 4-quinolone-3-carboxylic acids as inhibitors of hepatitis C virus

Quinolone-3-carboxylic acid represents a highly privileged chemotype in medicinal chemistry and has been extensively explored as antibiotics and antivirals targeting human immunodeficiency virus (HIV) integrase (IN). Herein we describe the synthesis and anti-hepatitis C virus (HCV) profile of a series of C-6 aryl substituted 4-quinlone-3-carboxylic acid analogues. Significant inhibition was observed with a few analogues at low micromolar range against HCV replicon in cell culture and a reduction in replicon RNA was confirmed through an RT-qPCR assay. Interestingly, evaluation of analogues as inhibitors of NS5B in a biochemical assay yielded only modest inhibitory activities, suggesting that a different mechanism of action could operate in cell culture.

Economic model of a birth cohort screening program for hepatitis C virus

Recent research has identified high hepatitis C virus (HCV) prevalence among older U.S. residents who contracted HCV decades ago and may no longer be recognized as high risk. We assessed the cost-effectiveness of screening 100% of U.S. residents born 1946-1970 over 5 years (birth-cohort screening), compared with current risk-based screening, by projecting costs and outcomes of screening over the remaining lifetime of this birth cohort. A Markov model of the natural history of HCV was developed using data synthesized from surveillance data, published literature, expert opinion, and other secondary sources. We assumed eligible patients were treated with pegylated interferon plus ribavirin, with genotype 1 patients receiving a direct-acting antiviral in combination. The target population is U.S. residents born 1946-1970 with no previous HCV diagnosis. Among the estimated 102 million (1.6 million chronically HCV infected) eligible for screening, birth-cohort screening leads to 84,000 fewer cases of decompensated cirrhosis, 46,000 fewer cases of hepatocellular carcinoma, 10,000 fewer liver transplants, and 78,000 fewer HCV-related deaths. Birth-cohort screening leads to higher overall costs than risk-based screening ($80.4 billion versus $53.7 billion), but yields lower costs related to advanced liver disease ($31.2 billion versus $39.8 billion); birth-cohort screening produces an incremental cost-effectiveness ratio (ICER) of $37,700 per quality-adjusted life year gained versus risk-based screening. Sensitivity analyses showed that reducing the time horizon during which health and economic consequences are evaluated increases the ICER; similarly, decreasing the treatment rates and efficacy increases the ICER. Model results were relatively insensitive to other inputs.

CONCLUSION

Birth-cohort screening for HCV is likely to provide important health benefits by reducing lifetime cases of advanced liver disease and HCV-related deaths and is cost-effective at conventional willingness-to-pay thresholds.

Triple therapy for HCV genotype 1 infection: telaprevir or boceprevir?

Boceprevir and telaprevir are the first two protease inhibitors available for the treatment of patients infected with hepatitis C virus (HCV) genotype 1. A sustained virological response (SVR) of 70-80% is observed when either of these protease inhibitors is utilized with pegylated interferon (PEG-IFN) and ribavirin (RBV) in treatment naïve patients. Both agents are also highly effective in patients who failed to achieve a SVR during previous treatment with PEG-IFN/RBV. A rapid virological response (RVR) is observed in 56-60% of treatment naïve patients. Patients who achieve a RVR can be treated with a shorter course of therapy (24-28 weeks) and still achieve a SVR rate of 90% or higher. Patients who do not achieve a RVR, those with cirrhosis and certain prior non-responders should be treated for 48 weeks. Although the SVR rates observed with boceprevir and telaprevir are quite similar both globally and within sub-populations, the treatment algorithms for the two agents are unique. The decision of which protease inhibitor to use should assess several factors including the treatment scheme, duration of therapy, adverse event profile, cost and the likelihood of achieving a RVR. The latter is highly dependent upon IFN sensitivity and the IL28B genotype.

The design, synthesis and biological evaluations of C-6 or C-7 substituted 2-hydroxyisoquinoline-1,3-diones as inhibitors of hepatitis C virus

C7-Substituted 2-hydroxyisoquinoline-1,3-diones inhibit the strand transfer of HIV integrase (IN) and the reverse-transcriptase-associated ribonuclease H (RNH). Hepatitis C virus (HCV) NS5B polymerase shares a similar active site fold to RNH and IN, suggesting that N-hydroxyimides could be useful inhibitor scaffolds of HCV via targeting the NS5B. Herein we describe the design, chemical synthesis, replicon and biochemical assays, and molecular docking of C-6 or C-7 aryl substituted 2-hydroxyisoquinoline-1,3-diones as novel HCV inhibitors. The synthesis involved an improved and clean cyclization method, which allowed the convenient preparation of various analogs. Biological studies revealed that the C-6 analogs, a previously unknown chemotype, consistently inhibit both HCV replicon and recombinant NS5B at low micromolar range. Molecular modeling studies suggest that these inhibitors may bind to the NS5B active site.

Mixing the right hepatitis C inhibitor cocktail

Therapy for hepatitis C virus (HCV) infection is on the cusp of a new era. Until now, standard-of-care therapy has involved interferon (IFN) and ribavirin. With the first successful Phase III trials of specific targeted antiviral therapy for HCV (STAT-C) compounds, as well as three trials in progress giving the first glimpse of IFN-free combinations of STAT-C agents, this review looks ahead to the new classes of anti-HCV agents currently in clinical development. Successful pharmacologic control of HIV and TB frames the discussion, as well as consideration of the mutation frequency of HCV replication. Maximizing synergy between agents and minimizing cumulative toxicity will be critical to the design of future IFN-free STAT-C regimens.