Drug eruptions induced by telaprevir in patients with chronic hepatitis C virus genotype 1 infection: a prospective study

INTRODUCTION

When co-administered with interferon and ribavirin, the prescription drug telaprevir significantly improves treatment response in patients with chronic hepatitis C virus (HCV) infection. Its use, however, also increases the likelihood of adverse effects that may lead to discontinuation of treatment. Cutaneous adverse effects are particularly common.

OBJECTIVE

To determine the frequency and clinical characteristics of drug eruptions induced by telaprevir in patients receiving HCV treatment and to analyze the clinical course of lesions and response to treatment.

MATERIAL AND METHODS

We performed a prospective observational study of all patients who started a treatment regimen that included telaprevir between May 2012 and July 2013. We recorded the demographic characteristics of the patients who developed telaprevir-induced eruptions, and analyzed the clinical characteristics of the lesions and their clinical course following the application of guideline-based treatment recommendations.

RESULTS

Twenty (46%) of the 43 patients who received triple therapy with interferon, ribavirin, and telaprevir during the study period developed drug reactions attributable to telaprevir. The reaction was classified as mild or moderate (grades 1 or 2) in 90% of cases and consisted of an exanthem with erythematous-edematous scaling plaques and papules. The rash worsened, mainly by spreading, in about one-third of cases. The skin lesions led to discontinuation of treatment in 2 patients (4.6%). Sustained viral response was achieved in 34 patients (79%).

CONCLUSIONS

Telaprevir-induced eruptions are common and often progress, but they rarely require patients to discontinue treatment.

Diabetes mellitus and advanced liver fibrosis are risk factors for severe anaemia during telaprevir-based triple therapy

BACKGROUND & AIMS

Adding telaprevir to pegylated-interferon and ribavirin increased both response rates and side effects of hepatitis C virus (HCV) treatment. We identified variables associated with severe anaemia during telaprevir-based triple therapy.

METHODS

An observational study was performed on 142 HCV-infected patients between June 2011 and March 2012. All subjects completed 12 weeks of telaprevir-based triple therapy or discontinued early because of anaemia. Severe anaemia was defined by a haemoglobin≤8.9 g/dl; advanced fibrosis was determined by Fib-4≥3.25.

RESULTS

The 47 (33%) patients who developed severe anaemia were similar to those who did not in sex, race, and prior response to dual therapy, but they were more likely to have diabetes (23.4% vs. 6.3%, P<0.01), advanced fibrosis (46.8% vs. 29.5%, P=0.04) and a history of anaemia during previous dual therapy (29.7% vs. 11.4%, P=0.02). Patients developing severe anaemia were older (59 vs. 56 years, P=0.02), had lower baseline platelet counts (134 vs. 163×10(9) /L, P=0.04), haemoglobin (14.0 vs. 15.0 g/dl, P<0.01), estimated glomerular filtration rate (79 vs. 90 ml/min/1.73 m2, P=0.03) and a higher median ribavirin/weight ratio (14.9 vs. 13.2 mg/kg, P<0.01). In multivariable logistic regression, presence of diabetes (OR=5.61, 95% CI: 1.59-19.72), Fib-4≥3.25 (OR=3.09, 95% CI: 1.28-7.46), higher ribavirin/weight ratio (OR=1.31 per mg/kg, 95% CI: 1.13-1.52) and lower baseline haemoglobin (OR=0.57 per g/dl, 95% CI, 0.41-0.80) were independently associated with developing severe anaemia.

CONCLUSIONS

Severe anaemia occurred in one-third of patients receiving telaprevir-based triple therapy. Risk was greater in patients with diabetes, advanced liver fibrosis, higher ribavirin/weight ratio and lower baseline haemoglobin.

Inhibition of the ribonuclease H activity of HIV-1 reverse transcriptase by GSK5750 correlates with slow enzyme-inhibitor dissociation

Compounds that efficiently inhibit the ribonuclease (RNase) H activity of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) have yet to be developed. Here, we demonstrate that GSK5750, a 1-hydroxy-pyridopyrimidinone analog, binds to the enzyme with an equilibrium dissociation constant (K(d)) of ~400 nM. Inhibition of HIV-1 RNase H is specific, as DNA synthesis is not affected. Moreover, GSK5750 does not inhibit the activity of Escherichia coli RNase H. Order-of-addition experiments show that GSK5750 binds to the free enzyme in an Mg(2+)-dependent fashion. However, as reported for other active site inhibitors, binding of GSK5750 to a preformed enzyme-substrate complex is severely compromised. The bound nucleic acid prevents access to the RNase H active site, which represents a possible biochemical hurdle in the development of potent RNase H inhibitors. Previous studies suggested that formation of a complex with the prototypic RNase H inhibitor β-thujaplicinol is slow, and, once formed, it dissociates rapidly. This unfavorable kinetic behavior can limit the potency of RNase H active site inhibitors. Although the association kinetics of GSK5750 remains slow, our data show that this compound forms a long lasting complex with HIV-1 RT. We conclude that slow dissociation of the inhibitor and HIV-1 RT improves RNase H active site inhibitors and may circumvent the obstacle posed by the inability of these compounds to bind to a preformed enzyme-substrate complex.

Hepatitis C and Why the Treatment is Needed Now? The Summary Report From the Cross-Border Symposium of the 5th Tehran Hepatitis Congress May 2013

The cross-border symposium on hepatitis C, entitled “why treating now?” was held on 15th May 2013 during the 5th International Tehran Hepatitis Congress. The present report summarizing communicated insights during this symposium is intended to help health care providers to make well-informed decisions when treating patients with chronic hepatitis C (CHC). Since today’s evolving science of hepatitis C management has introduced new treatment options, one should be well-versed about the potential benefits as well as untoward effects or practical challenges when using these regimens. In addition to outline HCV treatment advances, this symposium focused on the central question that why eligible patients with hepatitis C who may mostly benefit from the currently available protease inhibitors, should be treated now rather than be waited for the future therapies. Moreover, an overview of long term local experience with protease inhibitors in our challenging hepatitis C patients was presented during this interactive symposium.

Increasing antiviral treatment through integrated hepatitis C care: a randomized multicenter trial

Most individuals infected with the hepatitis C have not received antiviral treatment, with mental health and substance abuse problems being the primary barrier. Interventions have been developed to address these barriers among HCV patients considered "high-risk" for antiviral treatment. We present the design and methods of a prospective, randomized controlled multisite trial being conducted in the Veterans Affairs Healthcare System. The study employed a parallel design and the three study sites randomized a total of 364 VA patients with HCV to either Integrated Care (IC) or Usual Care (UC). The IC intervention consisted of a mental health provider (MHP) performing a) brief interventions to address risk factors; b) collaborative consultation with the HCV treatment clinicians; and c) case management prior to and during antiviral treatment. Clinical outcomes were abstracted from patient medical records and self-report questionnaires were completed at baseline, 4-months, 16-months, and 22-months after enrollment. The primary outcome of the study was sustained viral response (SVR). Secondary clinical outcomes were HCV treatment initiation and completion rates. Other secondary outcomes included substance use, depression, PTSD symptoms, quality of life, healthcare satisfaction, and healthcare utilization. The Integrated Care intervention has the potential to transform HCV antiviral treatment by increasing the number of HCV-infected individuals that can be successfully treated.

Dynamics of resistance mutations to NS3 protease inhibitors in a cohort of Brazilian patients chronically infected with hepatitis C virus (genotype 1) treated with pegylated interferon and ribavirin: a prospective longitudinal study

Abstract

About sixty thousand new cases of Hepatitis C virus (HCV) infection are recorded in Brazil each year. These cases are currently treated with pegylated interferon (PEG-IFN) and ribavirin (RBV) with an overall success rate of 50%. New compounds for anti-HCV therapy targeted to the HCV NS3 protease are being developed and some already form the components of licensed therapies. Mapping NS3 protease resistance mutations to protease inhibitors or anti-viral drug candidates is important to direct anti-HCV drug treatment.

Methods

Sequence analysis of the HCV NS3 protease was conducted in a group of 68 chronically infected patients harboring the HCV genotype 1. The patients were sampled before, during and after a course of PEG-IFN-RBV treatment.

Results

Resistance mutations to the protease inhibitors, Boceprevir and Telaprevir were identified in HCV isolated from three patients (4.4%); the viral sequences contained at least one of the following mutations: V36L, T54S and V55A. In one sustained virological responder, the T54S mutation appeared during the course of PEG-IFN and RBV therapy. In contrast, V36L and V55A mutations were identified in virus isolated from one relapsing patient before, during, and after treatment, whereas the T54S mutation was identified in virus isolated from one non-responding patient, before and during the treatment course.

Conclusions

The incidence and persistence of protease resistance mutations occurring in HCV from chronically infected patients in Brazil should be considered when using protease inhibitors to treat HCV disease. In addition, patients treated with the current therapy (PEG-IFN and RBV) that are relapsing or are non-responders should be considered candidates for protease inhibitor therapy.

Development of a robust luciferase reporter 1b/2a hepatitis C virus (HCV) for characterization of early stage HCV life cycle inhibitors

The development of JFH1 based intergenotypic recombinants that exploit the unique replication characteristics of JFH1 has made it possible to study infectious hepatitis C virus (HCV) encoding the structural genes of additional HCV genotypes. To facilitate the study of 1b structural proteins, we aimed to develop a robust 1b/2a chimera encoding a humanized Renilla luciferase reporter gene (1b/2a hRluc). The unadapted genome replicated efficiently but produced very low titers of infectious virus. Adaptation by continuous passage over a novel Huh-7 Lunet clone improved viral titers approximately 100-fold but caused an unexpected decline in luciferase activity, limiting the utility of the reporter-containing virus. Genotypic analysis revealed 17 adenosine to guanosine (A to G) nucleotide mutations in the luciferase gene and two potential adaptive mutations. To overcome the problems of low viral titers and editing of the luciferase gene during viral adaptation, six adaptive mutations previously identified in a non-reporter 1b/2a HCV genome were introduced into the 1b/2a hRluc genome. This resulted in the immediate production of high-titer viral stocks (approximately 1000-fold greater than the parental virus) that could efficiently infect naïve cells and generate robust luciferase signals. The improved sensitivity of the luciferase reporter also facilitated time of addition studies validating the utility of this system for characterizing the early steps of HCV infection. Thus, the development of the 1b/2a hRluc reporter virus described here provides a versatile tool for discovery of inhibitors targeting the early steps of the viral life cycle and genotype 1b structural genes.

Hepatitis C virus viral assays in the direct-acting antiviral era

In the direct-acting antiviral (DAA) era of hepatitis C virus (HCV) therapy, health care providers must be knowledgeable about genotype and subtype of HCV infection and interpretation of quantitative HCV viral assays to monitor treatment responses. They may also choose to assess interleukin 28B genotypes or resistance-associated variants after ineffective DAA therapy. DAA therapies require understanding of performance characteristics of quantitative HCV RNA assays and the definitions of terms used to report results. Only quantitative HCV RNA assays with a limit of detection of 10 to 15 IU/mL are appropriate for managing patients on DAA therapy.

Psammaplin A inhibits hepatitis C virus NS3 helicase

Hepatitis C virus (HCV) is the causative agent of hepatitis C, a chronic infectious disease that can lead to development of hepatocellular carcinoma. The NS3 nucleoside triphosphatase (NTPase)/helicase has an essential role in HCV replication, and is therefore an attractive target for direct-acting antiviral strategies. In this study, we employed high-throughput screening using a photo-induced electron transfer (PET) system to identify an inhibitor of NS3 helicase from marine organism extracts. We successfully identified psammaplin A as a novel NS3 inhibitor. The dose-response relationship clearly demonstrates the inhibition of NS3 RNA helicase and ATPase activities by psammaplin A, with IC₅₀ values of 17 and 32 μM, respectively. Psammaplin A has no influence on the apparent Km value (0.4 mM) of NS3 ATPase activity, and acts as a non-competitive inhibitor. Additionally, it inhibits the binding of NS3 to single-stranded RNA in a dose-dependent manner. Furthermore, psammaplin A shows an inhibitory effect on viral replication, with EC₅₀ values of 6.1 and 6.3 μM in subgenomic replicon cells derived from genotypes 1b and 2a, respectively. We postulate that psammaplin A is a potential anti-viral agent through the inhibition of ATPase, RNA binding and helicase activities of NS3.

Safety of telaprevir for chronic hepatitis C virus infection: a meta-analysis of randomized controlled trials

BACKGROUND

Previous studies have reported telaprevir is effective for chronic hepatitis C virus infection, but the safety of a telaprevir-based regimen remains uncertain.

OBJECTIVE

A meta-analysis was performed to assess the safety of the addition of telaprevir to a standard regimen of pegylated interferon (peginterferon) plus ribavirin (combination telaprevir with peginterferon plus ribavirin, the TPR group) compared with the standard regimen group (peginterferon plus ribavirin, the PR group).

METHODS AND RESULTS

Seven randomized controlled trials involving a total of 2808 patients were included in the meta-analysis. The addition of telaprevir to the standard regimen was associated with a significantly increased risk of serious adverse events compared with the standard PR group (relative risk [RR] = 1.56; 95% confidence interval [CI] 1.21, 2.03; p = 0.0007; I2 = 0%). Telaprevir was also associated with increased risk of treatment discontinuation (RR = 2.10; 95% CI 1.56, 2.83; p < 0.0001; I2 = 42%). In addition, telaprevir was more likely to cause nausea (RR = 1.39; p < 0.0001), diarrhoea (RR = 1.32; p = 0.004), pruritus (RR = 1.56; p = 0.0006), rash (RR = 1.60; p < 0.0001) and anaemia (RR = 1.55; p = 0.007). There was no difference in the other kinds of adverse events between the two groups. Sensitivity analysis further validated the credibility of the above outcomes.

CONCLUSION

Our meta-analysis raises safety concerns about the potential for an increased risk of serious adverse events associated with the use of telaprevir among patients with chronic hepatitis C virus infection, and cautious use of telaprevir is warranted.

Directly acting antivirals for the treatment of chronic hepatitis C: unresolved topics from registration trials

The Food and Drug Administration and European Medicines Agency approval of first generation directly acting antivirals NS3 protease inhibitors boceprevir and telaprevir opens a new era in the treatment of patients with chronic hepatitis C virus genotype 1 infection. Indeed telaprevir and boceprevir registration trials clearly showed a substantial improvement in rates of sustained virological response both in naive and in treatment-experienced patients, with the possibility of shortened regimens in a consistent subset of patients, through the optimization of treatment algorithms. Phases 2 and 3 studies also provided the basis for the management of side effects in order to maximize the safety profile of directly acting antivirals. However, the entry of triple therapy in current clinical practice comes with some unresolved topics, such as relevance of IL28B genetic testing and other pretreatment predictors in patient selection, use of the 4-week pretreatment lead-in phase with dual therapy, safety of triple therapy in some high-risk patient categories and specific management of directly acting antivirals-induced anaemia. As a consequence of these open issues, clinical practice guidelines on triple therapy released by American and European associations provide slightly different recommendations, effectively leaving these "grey" areas wide open for individual interpretation in everyday clinical practice.

IL28B polymorphism is not associated with HCV protease diversity in patients co-infected with HIV and HCV treated with pegylated interferon and ribavirin

Recent studies have demonstrated that IL28B polymorphisms predict therapeutic responses in chronic hepatitis C virus (HCV)-treated patients; however, the effect on HCV viral diversity, particularly on the HCV protease gene, is not clear. This study sought to evaluate the effect of IL28B polymorphisms on HCV diversity at NS3/4 protease region, which may influence therapeutic response to an HCV protease inhibitor based regimen. Twenty-two patients co-infected with HIV and HCV genotype 1, treatment-naïve on stable HIV antiretroviral therapy initiating interferon-based treatment were evaluated. Plasma HCV NS3 gene diversity was analyzed by clonal analysis at baseline and end of treatment. IL28B (rs12979860) genotypes were tested for associations with virologic outcomes and diversity parameters. There was similar baseline NS3 diversity in patients with CC (favorable) genotype compared to those with CT/TT (unfavorable) genotypes. There was no significant association between IL28B genotype and baseline NS3 nucleotide p-distance, dS-dN, amino acid p-distance, or nucleotide changes. Among patients without a sustained virologic response, between baseline and follow-up there was a significant trend towards decreased diversity after treatment among patients with favorable genotype, which was not observed in unfavorable genotypes. In patients treated with peginterferon/ribavirin therapy, IL28B polymorphism was not associated with enhanced NS3 diversity at baseline. Among non-SVR patients with the less favorable genotype, there was no change in diversity after treatment. This suggests that IL28B genotype is unlikely to have a negative impact on subsequent HCV PI efficacy in patients co-infected with HIV and HCV patients who have previously failed HCV therapy.

National patterns and predictors of liver biopsy use for management of hepatitis C

BACKGROUND & AIMS

Liver biopsy remains the standard, recommended method for assessing liver damage associated with chronic hepatitis C (HCV) infection. However, there is considerable debate about how liver biopsy should best be used, especially with the advent of more efficacious antiviral therapies. To identify the factors that influence the use of liver biopsy for HCV patients, we describe variations in liver biopsy use at the delivery system and patient level in a national VA sample.

METHODS

We analyzed VA HCV registry data for 171,893 VA patients with confirmed chronic HCV. Delivery system characteristics included geographic region and specialist time. Patient characteristics included antiviral treatment indicators, contraindications, volume of healthcare visits, and demographic variables. Logistic regression was used to explore correlates of biopsy use.

RESULTS

Liver biopsy use in the VA system increased from 1997 to 2003 but began declining in 2004. Rates of liver biopsy from 2004 to 2006 varied by VA region, ranging from 5% to 18%. Treatment contraindications and laboratory tests were significantly associated with more biopsies. Demographic variables (higher age, lower BMI, race/ethnicity, and less% service connected disability) were associated with fewer biopsies. Regional variability remained significant independent of volume of care and specialist time.

CONCLUSIONS

Liver biopsy rates in the VA system have variability that seems unrelated to clinical need. New antiviral therapies and non-invasive assessment techniques may create additional uncertainty for the role of liver biopsy, perhaps explaining its decline in recent years. The availability of more effective antiviral therapies may also affect biopsy rates in the future.

Inhibition of hepatitis C virus NS3 helicase by manoalide

The hepatitis C virus (HCV) causes one of the most prevalent chronic infectious diseases in the world, hepatitis C, which ultimately develops into liver cancer through cirrhosis. The NS3 protein of HCV possesses nucleoside triphosphatase (NTPase) and RNA helicase activities. As both activities are essential for viral replication, NS3 is proposed as an ideal target for antiviral drug development. In this study, we identified manoalide (1) from marine sponge extracts as an RNA helicase inhibitor using a high-throughput screening photoinduced electron transfer (PET) system that we previously developed. Compound 1 inhibits the RNA helicase and ATPase activities of NS3 in a dose-dependent manner, with IC(50) values of 15 and 70 μM, respectively. Biochemical kinetic analysis demonstrated that 1 does not affect the apparent K(m) value (0.31 mM) of NS3 ATPase activity, suggesting that 1 acts as a noncompetitive inhibitor. The binding of NS3 to single-stranded RNA was inhibited by 1. Manoalide (1) also has the ability to inhibit the ATPase activity of human DHX36/RHAU, a putative RNA helicase. Taken together, we conclude that 1 inhibits the ATPase, RNA binding, and helicase activities of NS3 by targeting the helicase core domain conserved in both HCV NS3 and DHX36/RHAU.