Predicting the therapeutic response in patients with chronic hepatitis C: the role of viral kinetic studies

Cleavage of intracellular hepatitis C RNA in the virus core protein coding region by deoxyribozymes

Hepatitis C virus (HCV) infection represents an important global health problem. Current antiviral therapeutics for HCV have proven inadequate in stemming the disease process. A novel therapeutic strategy involves the use of deoxyribozymes, also known as DNA enzymes or DNAzymes. These catalytic DNA molecules, designed to target and cleave specific RNA sequences, have shown promise in in vitro experimental models for various diseases and may serve as an alternative or adjunct to current HCV drug therapy. We designed and tested several deoxyribozymes that can bind and cleave highly conserved RNA sequences encoding the HCV core protein in in vitro systems. One of these deoxyribozymes reduced the level of our HCV RNA target by 32% and 48% after 24 h of cell exposure when tested in human hepatoma and epithelial cell lines, respectively. As this deoxyribozyme showed significant cleavage activity against HCV core protein target RNA in human cells, it may have potential as a therapeutic candidate for clinical trial in HCV infected patients.

Real-time multiplex PCR assay to quantify hepatitis C virus RNA in peripheral blood mononuclear cells

Ultrasensitive methods to measure very low levels of hepatitis C virus (HCV) RNA in biological samples may have diagnostic and prognostic significance and be useful to evaluate the response to antiviral treatment. A sensitive assay to quantify HCV RNA in peripheral blood mononuclear cells (PBMCs) was developed and validated using the iCycler iQ Detection System (Bio-Rad) coupled with TaqMan chemistry. HCV was co-amplified with the endogenous control glyceraldehyde-3-phosphate dehydrogenase in a multiplex reaction. Calculated PCR amplification efficiencies for both target and control genes were used in a mathematical model for relative quantitation of HCV RNA. A linear relationship between input RNA and C(T) values over 6 log dilutions was observed for both HCV- and GAPDH-specific products (R(2) > or = 0.99). As few as 1.5 IU/reaction could be detected, with high accuracy (CV < or= 3.94%) and reproducibility (CV < or = 2.20%). Quantitation of HCV RNA levels ranging from 10(3) to 10(7) IU/ml as measured in 47 plasma samples was highly correlated with values obtained by the COBAS Amplicor HCV Monitor test, v2.0 (Roche) (R(2) = 0.977). In conclusion, this assay provides an excellent tool to determine accurately HCV kinetics in PBMCs during antiviral therapy and to assess the long-term significance of different patterns of response to treatment.

Kinetics of hepatitis C virus RNA load during pegylated interferon alpha-2a and ribavirin treatment in naïve genotype 1 patients

Background

Pegylated interferon given for 24 or 48 weeks constitutes the most effective initial therapy for the treatment of chronic hepatitis C. It has been shown that viral load at week 2 appears the best time for predicting response to treatment. The objectives of this study were to assess whether the hepatitis C virus (HCV) RNA viral decline is predictive of sustained virological response (SVR) and to determine the best time for predicting complete response in our cohort of naïve patients treated with pegylated interferon alpha-2a (Peg-IFN alpha-2a) and ribavirin.

Results

Twenty patients treated with Peg-IFN alpha-2a and ribavirin for 48 weeks were studied. Six months after the end of treatment, a SVR (negative HCV RNA measured by PCR six months after the end of therapy) was obtained in 9 patients. Samples were obtained before and at week 2, 4, 8, and 12. At the end of week 2, viral load decreased more than 1.39 log in 8 out of the 9 patients with SVR and in 1 out of the 11 other patients. When we considered the viral load reduction from baseline to each week of treatment, week 2 appeared to be the best point time for predicting SVR, with a sensitivity of 91% (95%CI: 59;99), a specificity of 89% (52;98), a positive predictive value of 91% (59;99) and a negative predictive value of 89% (57;98).

Conclusion

During treatment with Peg-IFN alpha-2a plus ribavirin in genotype 1 patients, when the main objective of the treatment is viral eradication, viral kinetics showed that week 2 appeared to be the best time point for predicting SVR. Our results must be further confirmed on a larger cohort.

Predicting sustained virological responses in chronic hepatitis C patients treated with peginterferon alfa-2a (40 KD)/ribavirin

BACKGROUND/AIMS

Prediction of sustained virological response (SVR) during treatment would allow clinicians to identify patients most likely to benefit from therapy.

METHODS

Retrospective analysis of data from 1121 adults with chronic hepatitis C treated for 48 weeks with peginterferon alfa-2a (40 KD) 180 microg/week plus placebo or ribavirin (1000/1200 mg/day), or interferon alfa-2b 3 MIU three times/week plus ribavirin in a randomized, multinational, study.

RESULTS

67% of patients treated with peginterferon alfa-2a (40 KD)/ribavirin with early virological responses (HCV RNA negative or > or = 2 log10 decrease) at week 12 had SVRs at week 72 (HCV RNA < 50 IU/mL). The negative predictive value (NPV) was 97%. The probability of an SVR increased with the rapidity of HCV RNA suppression. The highest SVR rates were achieved in patients with rapid virological responses at week 4, but the corresponding NPV (74%) is too low for a decision criterion. In patients with early virological responses by week 12, the SVR rate was approximately 20% lower in those who received <80% compared with patients who received > or = 80% of the planned ribavirin dose.

CONCLUSIONS

Early, sustained suppression of HCV replication portends an SVR. Cessation of treatment may be contemplated in patients without a > or = 2 log10 reduction in HCV RNA after 12 weeks.

Pilot study of interferon gamma for chronic hepatitis C

BACKGROUND/AIMS

Currently, there are no effective therapies available for patients with chronic hepatitis C who have failed to respond to optimal interferon alfa-based regimens. The aims of this pilot study were to assess the antiviral activity and safety of interferon gamma in chronic hepatitis C.

METHODS

Patients with chronic hepatitis C, genotype 1, who had not responded to or who had relapsed after therapy with interferon alfa and ribavirin were enrolled in a trial of interferon gamma 1b given in doses of 100, 200 or 400 microg subcutaneously three times weekly for 4 weeks. Frequent blood samples were obtained for HCV RNA levels.

RESULTS

Fourteen patients were enrolled. Geometric mean HCV RNA levels remained unchanged. Serum aminotransferase levels also did not change, while there were significant decreases in neutrophil counts (-41% from baseline) and hematocrit (-5%). Low grade fever and malaise were common with the first injection of interferon gamma, but no serious side effects were encountered.

CONCLUSIONS

Although relatively well tolerated, interferon gamma in doses of 100-400 microg thrice weekly had no effect on HCV RNA levels in patients with chronic hepatitis C who had failed to achieve a sustained response to interferon alfa-based therapies.

Pegylated interferon alpha-2a with or without ribavirin in HCV/HIV coinfection: partially blinded, randomized multicenter trial

We evaluated the safety and efficacy of peginterferon alpha-2a (pegIFNalpha-2a), with or without ribavirin, in 154 HCV/HIV coinfected patients. All received pegIFNalpha-2a (180 microg/week) for 12 weeks, with those achieving an early virologic response (EVR) continued on monotherapy through week 48. Patients without an EVR were randomized at week 14 to also receive ribavirin (800 mg/day) or placebo through week 48. Patients with detectable HCV RNA at week 24 were discontinued. An EVR occurred in 59 of 154 patients on monotherapy, and a sustained virologic response (SVR) occurred in 19 of 55 of those achieving an EVR and continuing monotherapy through week 48. One week 12 nonresponder receiving pegIFNalpha-2a plus ribavirin, and none receiving pegIFNalpha-2a plus placebo, achieved a SVR. Discontinuations for adverse events occurred in 10 of 154 patients before, and 16 of 131 after, week 14. HIV RNA and CD4 counts did not change significantly during treatment. PegIFNalpha-2a was therefore at least as effective as standard interferon and ribavirin combination therapy and was well tolerated, without a negative impact on HIV parameters.

Leucoytapheresis with Adacolumn® enhances HCV-specific proliferative responses in patients infected with hepatitis C virus genotype 1

The most important aim in controlling virus infections is to destroy infected cells. Impaired cellular immunity in HIV and HCV infection leads to chronic infection. This study examined the effect of cytapheresis on the subsequent response to interferon/ribavirin treatment in patients infected with HCV. Adacolumn cytapheresis was carried out once a day for 5 consecutive days in patients who relapsed or did not respond to previous peginterferon and ribavirin combination treatment (n = 14: relapsers = 3, non-responders = 11). Peginterferon and ribavirin combination treatment was started after cytapheresis. During combination treatment, the proliferative response of peripheral blood mononuclear cells to HCV proteins (core, NS3, NS4, and NS5), tetanus toxoid, and phytohemagglutinin was measured, and compared to the early virological response. After treatment by leucocytapheresis, the proliferative response of peripheral blood mononuclear cells to HCV-core and tetanus toxoid increased significantly over the baseline (P < 0.05). A marked increase in the phytohemagglutinin response was observed after peginterferon and ribavirin combination treatment was started (P < 0.01 at week 5 and P < 0.005 at week 13). There were, however, no clear changes in the proliferative response to other antigens. Among the 14 patients, 12 (85.7%) achieved an early virological response by week 13 (12 weeks after the start of combination treatment). After treatment, nine patients (64.3%) had a significant proliferative response to HCV core antigen. Among the nine patients, eight patients (88.9%) achieved early virological response. The results indicate that activation of cellular immunity by leucocytapheresis facilitates an early virological response rate in HCV patients. This new therapy may, therefore, become an additional therapeutic measure for HCV.

Comparaison des cinétiques de l’ARN et de l’antigène de capside du virus de l’hépatite C dans le suivi thérapeutique des patients co-infectés par le virus de l’hépatite C et le virus de l’immunodéficience humaine, traités par bithérapie interféron–ribavirine, dans le cadre du protocole RIBAVIC

AIM OF STUDY

The RIBAVIC protocol, established by ANRS in 2001 and closed in 2003, compared the efficacy and the tolerance of two bitherapy anti-Hepatitis C Virus for HIV-HCV co-infected patients: IFN-ribavirin and PEG-IFN-ribavirin for 48 weeks. Two hundred patients from protocol were tested for hepatitis C virus core antigen, to study this viral marker kinetics, before and under treatment, in comparison with hepatitis C virus RNA evolution.

MATERIAL AND METHODS

The available samples for the 204 patients of our study were tested for RNA detection (COBAS AMPLICOR v2.0, Roche Diagnostics) and quantification (VERSANT HCV RNA v3.0, Bayer Diagnostics) and for quantification of core antigen (Ortho trak-C Assay, Ortho Clinical Diagnostics). The viral kinetics were established from samples quantified at D0, W2, W4, W12, W24, W48, W52, W72 (W =week), according to virological response assessed by PCR, six month after the end of treatment (non responders, sustained responders, relapsers et breakthroughs).

RESULTS

We obtained, for each type of response, similar evolution of both viral markers. Trak-C assay show to be enough sensitive, with similar results whatever genotype of hepatitis C virus. The Pearson's correlation is excellent (R =0.94; P <0.001). The intergenotype correlation is correct too, whatever HCV genotype (1, 2, 3, 4).

CONCLUSIONS

The HCV core antigen quantification by trak-C assay is a new tool for the follow-up of the treatment of patients with chronic hepatitis C and HIV co-infected.

Sudden hearing loss in patients with chronic hepatitis C treated with pegylated interferon/ribavirin

BACKGROUND

Sudden hearing loss has been reported on standard interferon (IFN)-alpha2 therapy. This is the first report on the occurrence of sudden hearing loss in six cases of chronic hepatitis C in temporal relation to treatment with pegylated (PEG)-IFN alfa2a or b/ribavirin combination therapy. Three patients were treated in an ongoing randomized placebo-controlled trial comparing the addition of 200 mg amantadine or placebo to the combination of 180 microg PEG-IFN alpha2a (PEGASYS, Roche, Basel, CH)/wk and 1-1.2 g ribavirin/d (COPEGUS, Roche, Nutley, USA) in de novo patients infected with HCV genotype 1. Sudden hearing loss and tinnitus developed on day 1 and after 4, 23, 25, 36, and 40 wk of treatment, respectively.

CONCLUSIONS

Sudden hearing loss may occur in about 1% of patients on PEG-IFN/ribavirin combination therapy. This rate was not different to that observed in an untreated population. Possible mechanisms involved include direct ototoxicity of IFN, autoimmunity, and hematological changes. In contrast to published cases on auditory disability due to standard IFN, hearing loss did not fully resolve after discontinuation of therapy with PEG-IFN. On the other hand, symptoms did not worsen on continued treatment. Therefore, the decision whether to continue or to stop the treatment when signs of ototoxicity appear is based on the clinical judgment of the treating physician.