Amino acid substitution in the core protein has no impact on relapse in hepatitis C genotype 1 patients treated with peginterferon and ribavirin

Effects of ribavirin monotherapy on the viral population in patients with chronic hepatitis C genotype 1: direct sequencing and pyrosequencing of the HCV regions

Ribavirin remains essential to chronic hepatitis C treatment. This paper investigates the influence of ribavirin priming to steady state before combined pegylated-interferon/ribavirin treatment on viral kinetics, ribavirin trough concentrations, genetic variability within HCV-core, -NS5B and -NS5A, and response to antiviral therapy. A prospective cohort study was made of 27 chronic hepatitis C genotype 1 naïve patients who received four weeks of ribavirin followed by pegIFN-α-2a/ribavirin for 48 weeks (Group A). The results obtained were compared with those for a control/historical group (Group B). In addition, direct sequencing and pyrosequencing were applied to determine ribavirin monotherapy-induced sequence changes. The rapid, early, and sustained virological response values obtained were 48%, 89%, and 52%, respectively, in Group A, and 52%, 90%, and 52% in Group B (P > 0.05). In the four-week combined treatment, the Group A patients showed a greater decrease in HCV-RNA (2.3 log10  IU/ml vs. 1.2 log10  IU/ml; P = 0.04), lower alanine aminotransferase levels (23.5 ± 1.33 U/L vs. 60.11 ± 18 U/L; P < 0.001) and higher mean ribavirin trough concentrations (3.28 ± 1.26 mg/L vs. 1.74 ± 0.7 mg/L; P = 0.001). No general increase in rates of nucleotide substitutions in the ribavirin monotherapy-treated patients was observed in NS5B, ISDR, or PKRbd, but there was a decrease in silent mutations in the HCV core (P = 0.04). This result was confirmed by pyrosequencing in the NS5A region. It is concluded that the ribavirin priming combined treatment with pegIFN-α-2a does not improve sustained virological response rates in HCV genotype 1 naïve infected patients. However, the greater reductions in viral load and alanine aminotransferase levels, together with the higher ribavirin trough concentration values obtained, could reflect the greater effectiveness of the treatment. Ribavirin does not have a mutagenic effect on the virus in patients with chronic hepatitis C.

Role of different regions of the hepatitis C virus genome in the therapeutic response to interferon-based treatment

Hepatitis C virus (HCV) is considered a significant risk factor in HCV-induced liver diseases and development of hepatocellular carcinoma (HCC). Nucleotide substitutions in the viral genome result in its diversification into quasispecies, subtypes and distinct genotypes. Different genotypes vary in their infectivity and immune response due to these nucleotide/amino acid variations. The current combination treatment for HCV infection is pegylated interferon α (PEG-IFN-α) with ribavirin, with a highly variable response rate mainly depending upon the HCV genotype. Genotypes 2 and 3 are found to respond better than genotypes 1 and 4, which are more resistant to IFN-based therapies. Different studies have been conducted worldwide to explore the basis of this difference in therapy response, which identified some putative regions in the HCV genome, especially in Core and NS5a, and to some extent in the E2 region, containing specific sequences in different genotypes that act differently with respect to the IFN response. In the review, we try to summarize the role of HCV proteins and their nucleotide sequences in association with treatment outcome in IFN-based therapy.

Combination of fluvastatin with pegylated interferon/ribavirin therapy reduces viral relapse in chronic hepatitis C infected with HCV genotype 1b

BACKGROUND AND AIM

Although the anti-hepatitis C virus (HCV) effect of statins in vitro and clinical efficacy of fluvastatin combined with Pegylated interferon (PEG-IFN)/ribavirin therapy for chronic hepatitis C (CHC) have been reported, the details of clinical presentation are largely unknown. We focused on viral relapse that influences treatment outcome, and performed a post-hoc analysis by using data from a randomized controlled trial.

METHODS

Thirty-four patients in the fluvastatin group and 33 patients in the non-fluvastatin group who achieved virological response (complete early virological response [cEVR] or late virological response [LVR]) with PEG-IFN/ribavirin therapy were subjected to this analysis. Factors contributing to viral relapse were identified by using multiple logistic regression analysis.

RESULTS

Relapse rate in patients with cEVR was significantly lower in the fluvastatin group (2 of 23, 8.7%) than in the non-fluvastatin group (9 of 26, 34.6%; P = 0.042). The use of fluvastatin decreased relapse rate in patients with LVR (27.3% vs 57.1%), though not significantly. Overall, relapse rate was significantly lower in the fluvastatin group (14.7%; 5 of 34) than in the non-fluvastatin group (39.4%; 13 of 33; P = 0.027). Multivariate analysis identified absence of fluvastatin (P = 0.027, odds ratio [OR] = 3.98, 95% confidence interval [CI] = 1.05-15.11) and low total ribavirin dose (P = 0.002, OR = 2.41, 95% CI = 1.38-4.19) as independent factors contributing to relapse.

CONCLUSION

The concomitant addition of fluvastatin significantly suppressed viral relapse, resulting in the improvement of sustained virological response rate, in PEG-IFN/ribavirin therapy for CHC patients with HCV genotype 1b and high viral load.

Prevalence of amino acid mutations in hepatitis C virus core and NS5B regions among Venezuelan viral isolates and comparison with worldwide isolates

BACKGROUND

Recent reports show that R70Q and L/C91M amino acid substitutions in the core from different hepatitis C virus (HCV) genotypes have been associated with variable responses to interferon (IFN) and ribavirin (RBV) therapy, as well to an increase of hepatocellular carcinoma (HCC) risk, liver steatosis and insulin resistance (IR). Mutations in NS5B have also been associated to IFN, RBV, nucleoside and non-nucleoside inhibitors drug resistance. The prevalence of these mutations was studied in HCV RNA samples from chronically HCV-infected drug-naïve patients.

METHODS

After amplification of core and NS5B region by nested-PCR, 12 substitutions were analyzed in 266 Venezuelan HCV isolates subtype 1a, 1b, 2a, 2c, 2b, 2j (a subtype frequently found in Venezuela) and 3a (n = 127 and n = 228 for core and NS5B respectively), and compared to isolates from other countries (n = 355 and n = 646 for core and NS5B respectively).

RESULTS

R70Q and L/C91M core substitutions were present exclusively in HCV G1b. Both substitutions were more frequent in American isolates compared to Asian ones (69% versus 26%, p < 0.001 and 75% versus 45%, p < 0.001 respectively). In Venezuelan isolates NS5B D310N substitution was detected mainly in G3a (100%) and G1a (13%), this later with a significantly higher prevalence than in Brazilian isolates (p = 0.03). The NS5B mutations related to IFN/RBV treatment D244N was mainly found in G3a, and Q309R was present in all genotypes, except G2. Resistance to new NS5B inhibitors (C316N) was only detected in 18% of G1b, with a significantly lower prevalence than in Asian isolates, where this polymorphism was surprisingly frequent (p < 0.001).

CONCLUSIONS

Genotypical, geographical and regional differences were found in the prevalence of substitutions in HCV core and NS5B proteins. The substitutions found in the Venezuelan G2j type were similar to that found in G2a and G2c isolates. Our results suggest a high prevalence of the R70Q and L/C91M mutations of core protein for G1b and D310N substitution of NS5B protein for the G3a. C316N polymorphism related with resistance to new NS5B inhibitors was only found in G1b. Some of these mutations could be associated with a worse prognosis of the disease in HCV infected patients.

Eradication of hepatitis C virus genotype 1 after liver transplantation by interferon therapy before surgery: Report of three patients with analysis of interleukin-28 polymorphism, hepatitis C virus core region and interferon-sensitivity determining region

The achievement of sustained viral response (SVR) with interferon (IFN) therapy before liver transplantation (LT) is difficult due to liver dysfunction, pancytopenia and frequent side-effects. Here, we report eradication of hepatitis C virus (HCV) genotype 1 after LT in three patients by IFN therapy before surgery. All three patients achieved virological response (VR), namely, fall in serum HCV RNA titer below the detection limit of real-time polymerase chain reaction (PCR) during IFN administration. However, HCV RNA rebound after cessation of treatment in all three patients; namely, they could not achieve SVR despite treatment with pegylated (PEG) IFN plus ribavirin. All three patients had wild-type amino acids (a.a.) at either aa70 or aa91 in the core region. Genotyping of IL-28 single nucleotide polymorphisms (rs8099917) showed TT genotype in two patients and TG genotype in one. All three patients developed multiple hepatocellular carcinomas during the clinical course, and requested living donor LT using liver grafts from their relatives. The patients were treated with IFN to immediately before LT, at which time they remained negative for HCV RNA in serum by real-time PCR. The three patients were followed-up for 14-15 months after LT, during which they remained negative for HCV RNA despite no further IFN therapy. In conclusion, it is possible to eradicate HCV after LT by inducing VR with continuous IFN therapy to before LT in spite of viral and host evidences reflecting low susceptibility to IFN treatment.