Treatment of non-genotype 1 hepatitis C virus patients

Hepatitis C Genotypes in Libya: Correlation with Patients' Characteristics, Level of Viremia, and Degree of Liver Fibrosis

OBJECTIVES

Our study sought to determine the distribution of hepatitis C virus (HCV)-genotypes among patients attending two tertiary care hospitals in Benghazi and Tripoli, Libya, and correlate this with patient's characteristics, viral load, and degree of fibrosis.

METHODS

We conducted a retrospective study of 286 HCV-RNA positive Libyan patients referred from different health care facilities in east and west Libya for specific HCV treatment. HCV genotyping was carried out by gene amplification. Liver histology was graded by Metavir score according to the stage of fibrosis.

RESULTS

HCV genotypes 1, 2, 3, and 4 were found in 24.1%, 10.8%, 3.4%, and 61.5% of the patients, respectively. Genotype 4 was detected more frequently in patients from east Libya (Benghazi) compared to west Libya (Tripoli) (75.9% vs. 41.6%, p = 0.245). Genotype 1 was more frequent in patients from west Libya compared to east Libya (34.1% vs. 16.8%, p = 0.657). There was a significant correlation between HCV genotype distribution and viral load. Patients with genotype 4 exhibited a higher degree of liver fibrosis (p < 0.001).

CONCLUSIONS

HCV genotype 4 is the predominant genotype in Libya followed by genotype 1. However, as we go from the east to the west of the country, genotype 1 increases. Genotype 4 was associated with higher level of viremia and higher stage of liver fibrosis. It is important to note that both genotypes 1 and 4 are associated with a poor response to pegylated interferon and ribavirin combination therapy. The findings emphasize the need to develop improved strategies in Libya for the successful treatment of HCV infection with novel newly available antiviral drugs.

Occurrence of genetic modifications in core, 5'UTR and NS5b of HCV associated with viral response to treatment

Background

It is becoming progressively more understandable that genetic variability of viruses is a major challenge in translating the laboratory findings to clinic. Genetic variability is the underlying cause of variant viral proteins which are not targetable by host immunological machinery.

Methods

500 patients were enrolled in study and amongst them, 451 patients were followed and categorized into two groups on the basis of their treatment response. Group 1 consisting of the 376 patients exhibited SVR while group 2 comprised 75 patients who were non-responders on the basis of viral load as evidenced by Real-Time PCR. Comparative sequence analysis was done between 75 non-responders and 75 responders (randomly picked from 376) by targeting three genomic regions, 5′UTR, core and NS5B and amplified products were directly sequenced and obtained sequences were cleaned, aligned and submitted to GenBank. Maximum Parsimony (MP) method was used for phylogenetic analysis and dendrograms were dragged using MEGA 5. Heterogeneity at nucleotide and amino acid level was determined using software BioEdit and DNAman while phosphorylation and N-linked glycosylation sites were determined using NetPhos 2.0 and SignalP-NN.

Results

Genotype 3 was prevalent in group 1 whereas non-responders indicated rare genotypes of Pakistan i.e. 4 and 5, genotype 6q and 6v were reported first time from Pakistan in this study. At nucleotide and amino acid level, the genetic distance and mutation, number of predicted N-phosphorylation and N-glycosylation sites was higher in group 2 as compared to group 1. Difference in percentage composition of individual amino acids was noted to be different between the two groups.

Conclusions

It can be concluded that heterogeneity both at nucleotide and amino acid level contributed in developing drug resistant phenotype. Moreover, occurrence of rare genotypes might hurdle the way to positive response of conventional treatment. Furthermore, prediction of phosphorylation and glycosylation sites could help in targeting the proper sites for drug designing.

Influence of a priori Information, Designs, and Undetectable Data on Individual Parameters Estimation and Prediction of Hepatitis C Treatment Outcome

Hepatitis C viral kinetic analysis based on nonlinear mixed effect models can be used to individualize treatment. For that purpose, it is necessary to obtain precise estimation of individual parameters. Here, we evaluated by simulation the influence on Bayesian individual parameter estimation and outcome prediction of a priori information on population parameters, viral load sampling designs, and methods for handling data below detection limit (BDL). We found that a precise estimation of both individual parameters and treatment outcome could be obtained using as few as six measurements in the first month of therapy. This result remained valid even when incorrect a priori information on population parameters was set as long as the parameters were identifiable and BDL data were properly handled. However, setting wrong values for a priori population parameters could lead to severe estimation/prediction errors if BDL data were ignored and not properly accounted in the likelihood function.

Hepatitis C virus resistance to new specifically-targeted antiviral therapy: A public health perspective

Until very recently, treatment for chronic hepatitis C virus (HCV) infection has been based on the combination of two non-viral specific drugs: pegylated interferon-α and ribavirin, which is effective in, overall, about 40%-50% of cases. To improve the response to treatment, novel drugs have been designed to specifically block viral proteins. Multiple compounds are under development, and the approval for clinical use of the first of such direct-acting antivirals in 2011 (Telaprevir and Boceprevir), represents a milestone in HCV treatment. HCV therapeutics is entering a new expanding era, and a highly-effective cure is envisioned for the first time since the discovery of the virus in 1989. However, any antiviral treatment may be limited by the capacity of the virus to overcome the selective pressure of new drugs, generating antiviral resistance. Here, we try to provide a basic overview of new treatments, HCV resistance to new antivirals and some considerations derived from a Public Health perspective, using HCV resistance to protease and polymerase inhibitors as examples.

The future developments in hepatology: no need for a jaundiced view

There have been major advances in the diagnosis and management of all forms of liver disease since the British Society of Gastroenterology first came into existence 75 years ago. In this review some of the exciting developments that are likely to enter into routine clinical practice over the next 5 years are highlighted. It is suggested that some critical changes need to take place in UK hepatology over the next decade to ensure that the management of liver disease in this country continues to be among the best in the world.

The pharmacokinetics of peginterferon alfa-2a and ribavirin in African American, Hispanic and Caucasian patients with chronic hepatitis C

BACKGROUND

Amongst Caucasian, Hispanic and African Americans with genotype 1 hepatitis C virus (HCV), there is a wide variation in response to treatment with peginterferon alfa-2a (PEG-IFN alfa-2a) and ribavirin.

AIM

To evaluate the pharmacokinetics (PK) of PEG-IFN alfa-2a and ribavirin among these three groups.

METHODS

Forty-seven patients with genotype 1 CHC (17 African Americans, 14 Hispanics and 16 Caucasians) received 8 weeks of PEG-IFN alfa-2a (180 μg/week) and ribavirin (1000 or 1200 mg/day). PEG-IFN alfa-2a serum concentrations and ribavirin plasma concentrations were measured following the first dose and at week 8. Pharmacokinetic parameters (C(max), T(max), AUC, CL/F) were estimated using noncompartmental methods.

RESULTS

There was no difference in the pharmacokinetic parameters for PEG-IFN alfa-2a following single-dose or steady-state administration between African American or Hispanic patients compared with Caucasian patients. Ribavirin pharmacokinetic parameters were similar between Hispanic and Caucasian patients for single-dose and steady-state administration. The single-dose C(max) was 33% lower (P < 0.05) in African American compared with Caucasian patients. Other ribavirin single-dose and steady-state pharmacokinetic parameters were slightly decreased (approximately 20% lower) in African American patients, but were not considered clinically meaningful.

CONCLUSIONS

No differences were observed in PEG-IFN alfa-2a pharmacokinetic parameters between African American or Hispanic patients compared with Caucasian patients. For ribavirin, no differences were observed in pharmacokinetic parameters between Hispanic and Caucasian patients. While a trend towards increased ribavirin clearance and decreased exposure was observed in African American patients vs. Caucasian patients, the differences were small and not considered clinically meaningful (Clinical Trial Number: NP17354).

UK consensus guidelines for the use of the protease inhibitors boceprevir and telaprevir in genotype 1 chronic hepatitis C infected patients

BACKGROUND

The nonstructural 3 serine protease inhibitors (PIs), boceprevir and telaprevir, represent the first in a new generation of directly acting antivirals against genotype 1 hepatitis C (HCV) infection. When used in combination with pegylated interferon and ribavirin, these drugs greatly improve sustained virological response rates in both treatment-naïve patients and patients who have had previous virological failure on treatment. However, the addition of these new agents will increase the complexity of therapeutic regimens, the rates of side-effects and costs.

AIMS

To review concisely the current evidence and to suggest current best practice, for the use of telaprevir and boceprevir in the management of chronic genotype 1 HCV infection.

METHODS

These guidelines for the use of boceprevir and telaprevir have been formulated following extensive review of the current literature, are based on the consensus opinion of a panel of national experts, and have been openly discussed and debated at a national meeting of HCV care providers.

RESULTS

We have made recommendations on a number of the key practical issues facing HCV care providers: (i) Which patients to treat?; (ii) Standards for the provision of care; (iii) Pre-treatment considerations; (iv) Which treatment regimens to use?; (v) Stopping rules; and (vi) Management of adverse effects. Finally, we have produced suggested algorithms for the assessment and treatment of these patients.

CONCLUSIONS

These UK Consensus guidelines indicate the current best practice for the use of boceprevir and telaprevir in the management of genotype 1 chronic HCV infection.