Predictors of a favorable response to alpha interferon therapy for hepatitis C

Gene polymorphisms of IL-10 and MxA in responders and non-responders to interferon therapy in HCV Egyptian patients genotype 4

Hepatitis C virus (HCV) is a major cause of chronic liver disease, with about 170 million people infected worldwide. The standard regimen for treatment of HCV consists of a combination of pegylated interferon with ribavirin. Failure of interferon-α treatment in patients with chronic HCV infection remains a challenging obstacle. Both viral and host environmental factors have been implicated in reducing responsiveness to IFN-α therapy. Host genetic diversity is also believed to contribute to the different clinical outcomes in HCV infection. The objective of the study was to investigate the association of both IL-10 (-819 and -592) and MxA (-88 and -123) single-nucleotide polymorphisms (SNPs) of the promoter regions, with response to interferon (IFN) therapy in Egyptian patients infected with HCV genotype 4. Polymorphisms of both genes in 85 HCV patients and 100 controls were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The frequency of SNP was compared between sustained responders (n = 52) and non-responders (n = 33), as determined by biochemical and virological response to IFN and ribavirin combined therapy. The frequency of the -819T/T and the -592A/A genotypes of IL-10 was significantly higher among responders compared to non-responders (51.92 vs 39.4 %, P = 0.03; 51.92 vs 42.42 %;P = 0.046 respectively). The G/G genotype at position -88 of the MxA gene was significantly lower in responders than in non-responders (25 vs 75.76 %, P = 0.046), whereas heterozygotes (G/T) were more likely responders (65.38 vs 18.18 %, P = 0). The -123C/A genotype was significantly associated with responders (48.08 vs 30.30 %, P = 0.014). Findings suggest that homozygosity for both -819T/T and -592A/A polymorphisms of IL-10 gene and that heterozygosity for both -88G/T and -123C/A polymorphisms of the MxA gene are important host factors that influence the response to IFN therapy in patients with chronic HCV infection.

High serum palmitic acid is associated with low antiviral effects of interferon-based therapy for hepatitis C virus

Hepatitis C virus (HCV) infection alters fatty acid synthesis and metabolism in association with HCV replication. The present study examined the effect of serum fatty acid composition on interferon (IFN)-based therapy. Fifty-five patients with HCV were enrolled and received IFN-based therapy. Patient characteristics, laboratory data (including fatty acids), and viral factors that could be associated with the anti-HCV effects of IFN-based therapy were evaluated. The effects of individual fatty acids on viral replication and IFN-based therapy were also examined in an in-vitro system. Multivariate logistic regression analysis showed that the level of serum palmitic acid before treatment and HCV genotype were significant predictors for rapid virological response (RVR), early virological response (EVR), and sustained virological response (SVR). High levels of palmitic acid inhibited the anti-HCV effects of IFN-based therapy. HCV replication assays confirmed the inhibitory effects of palmitic acid on anti-HCV therapy. The concentration of serum palmitic acid is an independent predictive factor for RVR, EVR, and SVR in IFN-based antiviral therapy. These results suggest that the effect of IFN-based antiviral therapy in patients with HCV infection might be enhanced by treatment that modulates palmitic acid levels.

Quantitative analysis of interferon alpha receptor subunit 1 and suppressor of cytokine signaling 1 gene transcription in blood cells of patients with chronic hepatitis C

Background

Interferon (IFN)-α receptor 1 (ifnar1) and suppressor of cytokine signaling 1 (socs1) transcription levels were quantified in peripheral blood mononuclear cells (PBMC) of 59 patients infected with hepatitis C virus (HCV) and 17 non-infected individuals. Samples were obtained from patients infected with HCV that were either untreated or treated with IFN-α2 plus ribavirin for 1 year and divided into responders and non-responders based on viral load reduction 6 months after treatment. Ifnar1 and socs1 transcription was quantified by real-time RT-PCR, and the fold difference (2^-ΔΔCT) with respect to hprt housekeeping gene was calculated.

Results

Ifnar1 transcription increased significantly in HCV-infected patients either untreated (3.26 ± 0.31), responders (3.1 ± 0.23) and non-responders (2.18 ± 0.23) with respect to non-infected individuals (1 ± 0.34; P = 0.005). Ifnar1 transcription increased significantly (P = 0.003) in patients infected with HCV genotypes 1a (4.74 ± 0.25) and 1b (2.81 ± 0.25) but not in 1a1b (1.58 ± 0.21). No association was found of Ifnar1 transcription with disease progress, initial viral load or other clinical factors. With respect to socs1 transcription, values were similar for non-infected individuals (1 ± 0.28) and untreated patients (0.99 ± 0.41) but increased in responders (2.81 ± 0.17) and non-responder patients (1.67 ± 0.41). Difference between responder and non-responder patients was not statistically significant. Socs1 transcription increased in patients infected with HCV genotypes 1a and 1b (2.87 ± 0.45 and 2.22 ± 0.17, respectively) but not in 1a1b (1.28 ± 0.40). Socs1 transcript was absent in three patients infected with HCV genotype 1b. A weak correlation between ifnar1 and socs1 transcription was found, when Spearman's correlation coefficient was calculated.

Conclusion

Our results suggest that HCV infection may up-regulate ifnar1 transcription. HCV genotypes differ in their capacity to affect ifnar1 and socs1 transcription, as well as in the ability to evade the antiviral response.

Modifications of T-lymphocyte subsets before and during interferon and ribavirin treatment for chronic hepatitis C infection

Our purpose was to determine in HCV-infected patients whether T-lymphocyte sub-populations were modified before and during interferon-alpha and ribavirin treatment, and whether this correlated with virological response. Twenty-two naive patients were given IFN-alpha 3 Million Units three times per week for 24 or 48 weeks and ribavirin. Sustained virological response corresponded to undetectable serum HCV RNA at treatment completion and 6 months later. Total blood lymphocyte counts and CD3(+)CD4(+), CD3(+)CD8(+), CD3(+)CD4(+)HLA-DR(+), and CD3(+)CD8(+)HLA-DR(+) lymphocyte subsets evaluated before, during, and after treatment were compared to values from 37 healthy subjects. At inclusion, patients and controls had similar total lymphocyte counts. CD3(+)CD4(+) counts and percentages were significantly higher in HCV patients. HLA-DR expression was also increased in CD4(+) (p < 0.0001) and CD8(+) T-cells (p = 0.0008) as compared with controls. During treatment, all lymphocyte subset counts and percentage decreased except the CD3(+)CD4(+) T-cell percentage which increased. Moreover, after 1 month of treatment, virological responders exhibited higher CD4(+) counts than nonresponders (p = 0.025), whereas they did not differ at inclusion or during the 2nd to 6th months of treatment. After treatment completion, all populations returned to baseline values. These results suggest that CD3(+)CD4(+) T-lymphocyte percentage increase under treatment could be related to IFN immunomodulation and associated with virological response.

Daily Interferon Monotherapy for Chronic Hepatitis C in Patients with Normal or Near-normal Serum Alanine Transaminase Levels: A Comparison of Two Protocols

OBJECTIVES

Up to 30% of the 5 million patients with chronic hepatitis C in the United States have normal serum alanine transaminase (ALT) levels. These individuals have not been treated aggressively, and reported response rates have been low. No study has targeted patients treated in a community practice setting.

METHODS

Consecutive patients with chronic hepatitis C with normal or near-normal serum ALT levels seen over a 2-year period in a community gastroenterology-hepatology practice were randomly assigned to receive either 3 MU or 6 MU daily interferon (IFN)-alpha-2a monotherapy for 12 months.

RESULTS

Sixteen patients (8 in each treatment arm) qualified for study. End-of-treatment response was 87.5% with 6 MU IFN daily and 75% with 3 MU IFN daily, whereas sustained virologic response was 62.5% and 50%, respectively. Genotype 1 patients had an improved outcome with the higher 6 MU dose.

CONCLUSIONS

Daily IFN monotherapy achieves high response rates in patients with chronic hepatitis C with normal or near-normal ALT. Present-day pegylated interferon regimes can be expected to be as effective.

Clinical laboratory assessment of hepatitis C and HIV coinfected patients according to the antiretroviral therapy received

During the year of 2001, a retrospective, descriptive study in order to determine the influence of the antiretroviral therapy received by 111 HIV-HCV coinfected patients who had undergone at least one liver biopsy was conduced, 74 of them were treated with a protease inhibitor regimen (WPI), and 37 with a non-protease inhibitor regimen (NPI). The main characteristics found were: a young patient population (mean age 41 years old in both groups), composed in most part of male individuals (74.3% WPI and 51.4% NPI) with previous risk factors for both infections (WPI 93.2% and NPI 89.2%). The most significant findings included AIDS-defining disease (WPI 18.9% and NPI 13.5% of the cases), elevated hepatic enzyme levels (WPI: SGOT 52.1 and NPI 53.2), absence of liver disease-related symptoms (16.2% for both groups), average CD4 count > 350 for both groups (WPI 362.2 and NPI 378.1), predominantly low-grade fibrosis in both populations (0-2 in 63.6% of WPI patients and in 80% of NPI patients), with necro-inflammatory activity ranging from 5-7 in 51.3% and 42.9% of WPI patients and NPI patients, respectively. It is suggested a sequential biopsy to better evaluate the evolution of the hepatic disease, according to the HAART regimen received.

Peginterferon alfa-2a: A review of approved and investigational uses

BACKGROUND

In October 2002, the US Food and Drug Administration approved peginterferon alfa-2a for the management of chronic hepatitis C virus (HCV) infection. The addition of polyethylene glycol (PEG) moiety to the interferon (IFN) molecule results in a product with altered pharmacokinetic properties.

OBJECTIVE

The aim of this article is to review the pharmacology, medications interactions, adverse events (AEs), and approved or investigational uses of PEG-IFN alfa-2a for viral hepatitis and oncologic conditions.

METHODS

Relevant articles were identified through searches of MEDLINE (1980-July 2003) and EMBASE (1980-July 2003). Search terms included, but were not limited to, peginterferon alfa-2a, pharmacokinetics, pharmacology, pharmacodynamics, and therapeutic use, as well as terms for specific disease states and AEs. Further publications were identified from citations of resulting papers.

RESULTS

Pegylation of IFN alfa-2a results in major changes in the pharmacokinetics of the product. Absorption is prolonged and serum concentrations are sustained over the dosing regimen. PEG-IFN alfa-2a has been shown to be more effective with or without ribavirin (RBV), in the management of treatment-naive patients with chronic HCV infection, than unmodified IFN alfa-2a with or without RBV. Results in other disease states are still preliminary. AEs are similar, in incidence and severity, to those occurring with unmodified IFN. They include earlier hematologic symptoms and fewer influenza-like symptoms. Drug-drug interactions are the same as those occurring with the unmodified IFN product.

CONCLUSIONS

The pharmacokinetic profile of IFN alfa-2a is improved by pegylation, which enables less frequent administration and results in improved efficacy with a similar side-effect profile. Combination of PEG-IFN alfa-2a with RBV is associated with a greater chance of achieving a sustained virologic response in treatment-naive patients with chronic HCV, compared with unmodified IFN alfa-2a/RBV combinations. Documentation of efficacy in other conditions awaits results of controlled clinical trials.

Interferon-alpha receptor 1 mRNA expression in peripheral blood mononuclear cells is associated with response to interferon-alpha therapy of patients with chronic hepatitis C

Interferon (IFN)-alpha receptor mRNA expression in liver of patients with chronic hepatitis C has been shown to be a response to IFN-alpha therapy. The objective of the present study was to determine whether the expression of mRNA for subunit 1 of the IFN-alpha receptor (IFNAR1) in peripheral blood mononuclear cells (PBMC) is associated with the response to IFN-alpha in patients with chronic hepatitis C. Thirty patients with positive anti-HCV and HCV-RNA, and abnormal levels of alanine aminotransferase in serum were selected and treated with IFN-alpha 2b for one year. Those with HBV or HIV infection, or using alcohol were not included. Thirteen discontinued the treatment and were not evaluated. The IFN-alpha response was monitored on the basis of alanine aminotransferase level and positivity for HCV-RNA in serum. IFNAR1-mRNA expression in PBMC was measured by reverse transcription-polymerase chain reaction before and during the first three months of therapy. The results are reported as IFNAR1-mRNA/beta-actin-mRNA ratio (mean +/- SD). Before treatment, responder patients had significantly higher IFNAR1-mRNA expression in PBMC (0.67 +/- 0.15; N = 5; P < 0.05) compared to non-responders (0.35 +/- 0.17; N = 12) and controls (0.30 +/- 0.16; N = 9). Moreover, IFNAR1-mRNA levels were significantly reduced after 3 months of treatment in responders, whereas there were no differences in IFNAR1 expression in non-responders during IFN-alpha therapy. Basal IFNAR1-mRNA expression was not correlated with the serum level of alanine and aspartate aminotransferases or the presence of cirrhosis. The present results suggest that IFNAR1-mRNA expression in PBMC is associated with IFN-alpha response to hepatitis C and may be useful for monitoring therapy in patients with chronic hepatitis C.

Genetic polymorphisms and the progression of liver fibrosis: a critical appraisal

Liver fibrosis is a highly dynamic process in which multiple genes interact with environmental factors. Recent human epidemiologic studies have identified possible polymorphisms in a number of candidate genes that influence the progression of liver fibrosis. These genetic factors could explain the broad spectrum of responses to the same etiologic agent found in patients with chronic liver diseases. Polymorphisms in genes encoding immunoregulatory proteins, proinflammatory cytokines, and fibrogenic factors may influence disease progression in patients with alcohol-induced liver disease, primary biliary cirrhosis, or chronic hepatitis C. However, some of the studies have yielded contradictory results. For example, conflicting results have been obtained in studies assessing the role of mutations in the hemochromatosis gene on fibrosis progression in patients with chronic hepatitis C. Large-scale, well-designed studies are required to clarify the actual role of this factor and other genetic variants in liver fibrosis.

The rate of fibrosis progression is an independent predictor of the response to antiviral therapy in chronic hepatitis C

The response to antiviral therapy and the rate of fibrosis progression in chronic hepatitis C virus (HCV) infection are related to common factors, including age and gender. The aim of this study was to evaluate the relationship between the rate of fibrosis progression and the sustained virologic response (SVR) to interferon (IFN)-based treatment. A total of 332 patients treated for chronic HCV infection were evaluated. Using multivariate logistic regression analysis, the impact of the rate of fibrosis progression (defined as the stage of liver fibrosis according to the Metavir system/duration of infection) on the rate of SVR (negative HCV RNA at least 6 months following the end of treatment), was determined. The median age of the patients was 44 (range 25-77) years, 64% were male, and 66% were infected with genotypes 1, 4, 5 or 6. The median rate of fibrosis progression was 0.083 (range 0-2) Metavir units/year; 158 patients (48%) had F2-F4 fibrosis. After a median of 48 (range 2-126) weeks of therapy (IFN, n=190; IFN and ribavirin, n=96; pegylated IFN, n=20; pegylated IFN and ribavirin, n=26), 93 patients (28%) achieved an SVR. In univariate analysis, the rate of SVR was higher in slow [< 0.083 Metavir units/year (n=162)] than rapid progressors [> or = 0.083 Metavir units/year (n=170)] (35%vs 22%, P=0.01). After controlling for age, gender, genotype, viral load, and treatment regimen and duration, the rate of fibrosis progression remained an independent predictor of SVR (slow vs rapid progressors, OR 2.74; 95% CI 1.27-5.92; P=0.01). Hence the rate of fibrosis progression is an independent predictor of SVR to IFN-based therapy in patients with chronic hepatitis C. This additional factor should be considered in economic models evaluating this condition.

Prognostic factors and early predictability of sustained viral response with peginterferon alfa-2a (40KD)

BACKGROUND/AIMS

Baseline factors and early decline in serum hepatitis C virus RNA are predictive of sustained virological response to interferon therapy in patients with chronic hepatitis C. We evaluated the prognostic value of baseline factors and early viral RNA among patients treated with peginterferon alfa-2a (40KD).

METHODS

Data were pooled from three randomized trials involving 814 patients treated with peginterferon alfa-2a (40KD) (90, 135, or 180 mirog). Stepwise and multiple logistic regression identified independent baseline factors associated with response. Receiver operating characteristic curves for both absolute values and log(10) decline in viral RNA at 4, 8, 12 and 24 weeks of therapy were created.

RESULTS

Independent prognostic factors for sustained virological response included viral genotype non-1, low pretreatment viral load, age (<40 years), no cirrhosis and body weight (<85 kg). In addition, alanine aminotransferase quotient (>3) and histological activity index score (>10) were also independently prognostic. Receiver operating characteristic curves showed that detectable or less than 2-log(10) decline in viral RNA at week 12 predicted sustained virological non-response (negative predictive value is 98%) .

CONCLUSIONS

In patients with chronic hepatitis C treated with peginterferon alfa-2a (40KD), the decision to continue or stop treatment can be made as early as week 12.

Interferon alfacon-1: a review of its pharmacology and therapeutic efficacy in the treatment of chronic hepatitis C

Interferon alfacon-1 (consensus interferon) is a non-naturally occurring, synthetic, type 1 interferon (IFN)alpha that is used for the treatment of patients with chronic hepatitis C. The efficacy of subcutaneously administered interferon alfacon-1 has been demonstrated in clinical trials during the treatment of LFN-naive patients (interferon alfacon-1 9microg 3 times a week for 24 weeks) and retreatment of nonresponders and relapsers to previous interferon therapy (interferon alfacon1 15 microg 3 times a week for up to 48 weeks). Higher and more frequent interferon alfacon-1 dosages have also been investigated. Results from a pivotal double-blind randomised trial in 704 patients with chronic hepatitis C showed that interferon alfacon-19 microg 3 times a week achieved virological and biochemical response rates of 34.9 and 42.2%, respectively, at treatment end-point (week 24). Sustained virological and biochemical responses (week 48) were reported in 12.1 and 20.3% of the patients, respectively. In general, response rates in recipients of interferon alfacon-1 9 microg 3 times a week were similar to those achieved with IFN-alpha2b 3 MIU 3 times a week. However, interferon alfacon-1 was more effective in the subgroup of patients infected with hepatitis C virus (HCV) genotype 1 at end-point (virological response, 24 vs 15%; p < 0.05) and post-treatment observation period (8 vs 4%) although the difference between treatment groups was statistically significant only at treatment end-point. The sustained virological response rate achieved in patients with high baseline levels of serum HCV RNA receiving interferon alfacon-1 was statistically superior to that exhibited in the IFN-alpha2b treatment group (7 vs 0%; p < Interferon alfacon-1 also showed efficacy during the retreatment of non-responders and relapsers to previous IFN therapy in a large nonblind multicentre trial. Sustained virological response (week 72) was observed among 13 and 58% of nonresponders and relapsers, respectively, after 48 weeks of treatment with interferon alfacon-1 15 microg 3 times a week. Interferon alfacon-1 has been generally well tolerated in clinical trials. As with other IFNs, adverse events were reported frequently but were usually considered of mild to moderate severity, decreased with time and caused a small percentage of patients to withdraw from the treatment. Fever, fatigue, arthralgia, myalgia, headache and rigors were the most frequently reported adverse events. Psychiatric adverse events appeared to be dose-related and caused the majority of treatment withdrawals.

CONCLUSION

Interferon alfacon-1 is generally well tolerated and is an effective agent in the treatment of patients with chronic hepatitis C. Comparative data from a pivotal randomised trial indicate that the drug has at least equivalent efficacy to IFNalpha-2b, and a statistically significant advantage was demonstrated at treatment end-point in patients infected with HCV genotype 1. A number of ongoing trials with interferon alfacon-1 are evaluating issues such as the optimal dosage regimen and duration of therapy in an effort to improve sustained virological response to therapy, a goal for IFNs in general.