Different turnover rate of hepatitis C virus clearance by different treatment regimen using interferon-beta

Host Cell Targets in HCV Therapy: Novel Strategy or Proven Practice?

The development of novel antiviral drugs against hepatitis C is a challenging and competitive area of research. Progress of this research has been hampered due to the quasispecies nature of the hepatitis C virus, the absence of cellular infection models and the lack of easily accessible and highly representative animal models. The current combination therapy consisting of interferon-α and ribavirin mainly acts by supporting host cell defence. These therapeutics are the prototypic representatives of indirect antiviral agents as they act on cellular targets. However, the therapy is not a cure, when considered from the long-term perspective, for almost half of the chronically infected patients. This draws attention to the urgent need for more efficient treatments. Novel anti-hepatitis C treatments under study are directed against a number of so-called direct antiviral targets such as polymerases and proteases, which are encoded by the virus. Although such direct antiviral approaches have proven to be successful in several viral indications, there is a risk of resistant viruses developing. In order to avoid resistance, the development of indirect antiviral compounds has to be intensified. These act on host cell targets either by boosting the immune response or by blocking the virus host cell interaction. A particularly interesting approach is the development of inhibitors that interfere with signal transduction, such as protein kinase inhibitors. The purpose of this review is to stress the importance of developing indirect antiviral agents that act on host cell targets. In doing so, a large source of potential targets and mechanisms can be exploited, thus increasing the likelihood of success. Ultimately, combination therapies consisting of drugs against direct and indirect viral targets will most probably provide the solution to fighting and eradicating hepatitis C virus in patients.

Indices of initial hepatitis C virus RNA reduction rate to predict efficacy of interferon-beta followed by peginterferon plus ribavirin for genotype 1b high viral load

AIM

Initial hepatitis C virus (HCV) RNA reduction was investigated as a potential index for sustained virological response (SVR) in the treatment of interferon (IFN)-β followed by peginterferon plus ribavirin (PEG IFN/RBV).

METHODS

The treatment course was retrospectively analyzed in 64 genotype 1b patients with a HCV RNA level of 5.0 logIU/mL or higher. IFN-β was administrated twice a day for 2 weeks followed by 24 or 48 weeks of PEG IFN/RBV. The serum HCV RNA level was measured by real-time polymerase chain reaction before administration and at 1, 2 and 4 weeks of therapy.

RESULTS

By the duration of PEG IFN administration, the SVR rates were 11% (2/18, <19 weeks), 64% (23/36, 20-24 weeks) and 40% (4/10, 25-72 weeks) (P = 0.0011, χ(2) -test). The SVR rate was high in patients in whom the HCV RNA level had decreased by 2.5 logIU/mL or greater at 1 week of IFN-β (29/55 [53%] vs 0/9 [0%], P = 0.0029, χ(2) -test). Among these patients, the SVR rate was even higher in those with continuous reduction in the first 2 weeks after the switch to PEG IFN/RBV (27/45 [60%] vs 2/10 [20%], P = 0.0048). Age below 65 years, no previous IFN course and good initial HCV RNA reduction were significantly associated with SVR on multivariate analysis, and the SVR rate was 95% (18/19) among these patients.

CONCLUSION

The 2.5 logIU/mL reduction in HCV RNA at 1 week of IFN-β and the continuous reduction just after the switch to PEG IFN/RBV are important SVR-predictive indices.

Efficacy of the regimen using twice-daily β-interferon followed by the standard of care for chronic hepatitis C genotype 1b with high viral load

AIM

  In patients with refractory genotype 1b chronic hepatitis C with high viral loads, we retrospectively compared the efficacy of standard of care treatment (SOC: combined PEG-IFN-α-2b/ribavirin for 48 weeks) and a regimen in which 2 weeks of SOC induction was replaced by twice-daily β-interferon alone (IFN-β induction therapy).

METHODS

  Seventeen patients received the IFN-β induction therapy plus SOC (IFN-β induction group) and 13 patients received SOC alone (SOC group).

RESULTS

  In the IFN-β induction group and SOC group, early virological response (EVR) rates were 88.2% and 53.8%, respectively. The end of treatment rates were 100.0% and 92.3%, and sustained virological response (SVR) rates were 70.6% and 53.8%, respectively. By induction with IFN-β, even in refractory cases, the high virus negative conversion rate in the early treatment phase and actions of pegylated IFN-α-2b and ribavirin in the maintenance treatment phase led to an additive effect. In the analysis of contributing factors, only the achievement of EVR was associated with a significant difference in SVR (P = 0.0011). The univariate logistic regression analysis showed that only IFN-β treatment was associated with a significant difference in EVR (P = 0.0492, odds ratio = 6.248, 95% confidence interval = 1.026-40.252), whereas no significant factors were found in the multivariate analysis due to small samples.

CONCLUSION

  IFN-β induction therapy with higher EVR might be beneficial for protease inhibitor-refractory chronic hepatitis C patients.

Twenty four-week peginterferon plus ribavirin after interferon-β induction for genotype 1b chronic hepatitis C

AIM

To investigate the possibility of shortening the duration of peginterferon (Peg-IFN) plus ribavirin (RBV) combination therapy by incorporating interferon-β (IFN-β) induction therapy.

METHODS

A one treatment arm, cohort prospective study was conducted on seventy one patients. The patients were Japanese adults with genotype 1b chronic hepatitis C, HCV-RNA levels of ≥ 5.0 Log IU/mL or 100 KIU/mL, and platelet counts of ≥ 90 000/μL. The treatment regimen consisted of a 2 wk course of twice-daily administration of IFN-β followed by 24 wk Peg-IFN plus RBV combination therapy. We prolonged the duration of the Peg-IFN plus RBV therapy to 48 wk if the patient requested it.

RESULTS

The patients, including 44% males, were characterized by an median age of 63 years (range: 32-78 years), an median platelet count of 13.9 (range: 9.1-30.6) × 10(4)/μL, 62% IFN-naïve, and median HCV-RNA of 6.1 (range: 5.1-7.2) Log IU/mL. The sustained virologic response (SVR) rates were 34% (Peg-IFN: 1-24 wk, n = 61, 95% confidence interval (CI): 24%-47%) and 55% (Peg-IFN: 20-24 wk, n = 31, 95% CI: 38%-71%, P < 0.001; vs Peg-IFN: 1-19 wk). The SVR rate when the administration was discontinued early was 13% (Peg-IFN: 1-19 wk, n = 30, 95% CI: 5%-30%), and that when the administration was prolonged was 50% (Peg-IFN: 25-48 wk, n = 10, 95% CI: 24%-76%, P < 0.05; vs Peg-IFN: 1-19 wk). In the patients who received 20-24 wk of Peg-IFN plus RBV, only the higher platelet count (≥ 130 000/μL) was significantly correlated with the SVR (odds ratio: 11.680, 95% CI: 2.3064-79.474, P = 0.0024). In 45% (14/31) of the patients with a higher platelet count (≥ 130 000/μL) before therapy, the HCV-RNA level decreased to below 3.3 Log IU/mL at the completion of IFN-β, and their SVR rate was 93% (13/14) after 20-24 wk administration of Peg-IFN plus RBV.

CONCLUSION

These results suggest the possibilities of shortening the duration of Peg-IFN plus RBV combination therapy by actively reducing HCV-RNA levels using the IFN-β induction regimen.

Advantage of IFN-beta/alpha2b same-day administration for ribavirin-intolerant patients with chronic hepatitis C

AIM

Although interferon (IFN)/ribavirin is the mainstream combination treatment for chronic hepatitis C in patients with a high viral load, ribavirin is problematic for women of childbearing age and patients with anemia. Therefore we needed to establish a new regimen without ribavirin.

METHODS

We devised a new regimen (same-day beta/alpha2b) to administer IFN-beta and alpha2b on the same-day, and compared it with IFN-alpha2b alone and IFN-alpha2b plus ribavirin. The cases were 36 patients (26.1%) in whom ribavirin could not be used (young women, anemia, etc.) among 138 patients who underwent IFN treatment after ribavirin release.

RESULTS

The percentages of patients withdrawing due to side-effects were 6.8%, 18.8% and 17.0% in the treatment with same-day beta/alpha2b, IFN-alpha2b alone and IFN-alpha2b plus ribavirin groups, respectively. In genotype 1b, the sustained viral response (SVR) was 28.6% (4/14), 13.6% (3/22) and 25.0% (8/32) with a high viral load, and 91.7% (11/12), 27.3% (3/11) and 57.1% (4/7) with a low viral load for the respective groups. According to a study on viral half-life during the early phase of IFN therapy, there was no difference among the regimens of same-day IFN-beta/alpha2b, beta alone, alpha2b alone and twice-daily treatment with IFN-beta. Same-day beta/alpha2b treatment showed a significantly higher SVR rate in moving type patients with a genotype 1b/high viral load.

CONCLUSIONS

Same-day beta/alpha2b treatment resulted in few cases where therapy was discontinued and showed a high SVR rate. This regimen is especially appropriate in cases where ribavirin has been deemed unsuitable.

Is {beta}-interferon a promising therapeutic option for the management of hepatitis C?

Using interferon-alpha (IFN-alpha) as the conventional therapeutic antiviral drug, physicians generally achieve a treatment success of <50% in cases with chronic hepatitis C. Owing to the structural similarities between IFN-alpha and interferon-beta (IFN-beta), the latter is a candidate for obtaining sustained viral response. In this review, we have compiled the published information on the use of IFN-beta for the management of acute and chronic hepatitis C up to 2007. We have looked at the rates of success and side effects. IFN-beta might be helpful if IFN-alpha fails to achieve a favourable outcome. This antiviral drug may be helpful for the management of chronic hepatitis C in both age extremes, in case of a relapse after receiving IFN-alpha and for preventing the development of the carrier state after acute hepatitis C. Further studies are required on the efficacy of IFN-beta for the management of acute and chronic hepatitis C.

Growth inhibitory effects of IFN-beta on human liver cancer cells in vitro and in vivo

We investigated the effects of interferon-beta (IFN-beta) on the growth of human liver cancer cells. The effects of IFN-beta with or without 5-fluorouracil (5-FU) on the proliferation of 13 liver cancer cell lines were investigated in vitro. Chronologic change in IFN-alpha receptor 2 (IFNAR-2) expression was monitored in hepatocellular carcinoma (HCC) cells (HAK-1B) cultured with IFN-beta. After HAK-1B cells were transplanted into nude mice, various doses of IFN-beta were administered, and the tumor volume, weight, histology, tumor blood vessel, and angiogenesis factor expression were examined. IFN-beta inhibited the growth of 11 cell lines with apoptosis in a dose-dependent and time-dependent manner. With IFN-beta, IFNAR-2 expression in HAK-1B cells was significantly downregulated from 6 to 12 h. IFN-beta induced a dose-dependent decrease in tumor volume and weight and a significant increase of apoptosis in the tumor. Both basic fibroblast growth factor (bFGF) and blood vessel number in the tumor decreased only in mice receiving the lowest dose (1000 IU) of IFN-beta. IFN-beta with 10 muM of 5-FU frequently induced synergistic antiproliferative effects. IFN-beta with or without 5-FU induces strong antitumor effects in HCC cells, and we conclude that IFN-beta is useful for the prevention and treatment of HCC.

Potent induction therapy with interferon and ribavirin combination therapy does not achieve a higher sustained virological response rate in chronic hepatitis C with genotype 1b and high hepatitis C virus RNA level

AIMS

To compare twice-daily interferon (IFN)-beta administration and once-daily IFN-alpha-2b administration as induction therapy in ribavirin combination therapy in chronic hepatitis C with a high viral load of genotype-1b hepatitis C virus (HCV).

METHODS

Sixty-one chronic hepatitis patients with a high viral load of genotype-1b HCV were randomly divided into three groups: group A was given IFN-beta 6 MU induction therapy twice daily for 2 weeks; group B was given IFN-alpha-2b 6 MU induction therapy once daily for 2 weeks; and group C was given no induction therapy. All three groups were then given IFN-alpha-2b 6 MU 3 days/week for the rest of the 24-week study period. Ribavirin was given for the entire 24-week study period.

RESULTS

Although the cumulative HCV-RNA negative rates tended to be higher in group A than in group B, the differencewas not significant. The HCV-RNA negative rate at week 2 was significantly higher in groups A and B than in group C (P < 0.05). The sustained virological response (SVR) rate was 16% overall, 21% for groups A and B, and 5% for group C; the SVR rate of groups A plus B tended to be higher than that of group C (P = 0.093).

CONCLUSIONS

There was no difference between the effects of the two induction therapies; potent induction therapy does achieve higher early viral clearance but not a higher SVR rate.

Prolonged Negative HCV-RNA Status Led to a Good Outcome in Chronic Hepatitis C Patients with Genotype 1b and Super-High Viral Load

OBJECTIVE

We examined whether a sustained negative HCV-RNA status for 48 weeks affects the outcome in patients with genotype 1b and super-high viral load, and also investigated whether the outcome is affected by the induction therapy of twice-daily pre-administrated interferon (IFN)-beta.

METHODS

78 eligible patients were divided into four groups. 40 were patients assigned to the short treatment protocol. 13 patients received 3 MU IFN-beta twice daily for 2 weeks followed by IFN-alpha2b+ribavirin for 22 weeks (beta-induction group: group 1). 27 patients received IFN-alpha2b+ribavirin for 24 weeks (standard combination group: group 2). 38 patients were assigned to the maintenance treatment protocol. All of the 13 in the beta-induction group (group 3) and 21 of 25 patients in the standard combination group (group 4) who were negative HCV-RNA PCR at week 24 had IFN monotherapy to maintain a negative HCV-RNA result for 48 weeks.

RESULTS

An HCV-RNA-negative status at week 24 was observed in 96% (25/26) of groups 1 and 3 versus in 79% (41/52) of groups 2 and 4 (p<0.01). The sustained virological response (SVR) was 38% (5/13) in group 1 and 11% (3/27) in group 2 (p<0.05). In the maintenance treatment, SVR was observed in 46% (6/13) of group 3 and 32% (8/25) of group 4 (NS).

CONCLUSIONS

A sustained negative HCV-RNA status for 48 weeks might be associated with viral elimination in patients with genotype 1 and super-high viral load.

Is interferon-beta an alternative treatment for chronic hepatitis C

The treatment of chronic hepatitis C (CHC) is still far from optimal, particularly for those subpopulations that do not respond to the standard combination therapy with Interferon-α (IFNα) plus ribavirin. Although in some cases the use of higher doses or longer treatment periods may be effective, these approaches are generally associated with a higher incidence of adverse events, which may either lead to a reduction in patient compliance or require drug withdrawal. IFNβ could represent an interesting alternative for treating CHC patients. Controversial data about IFNβ efficacy in CHC exist, the main reason being that many results stem from pilot studies with small cohorts of patients. However, promising results have been obtained in some subgroups of patients that fail to respond to IFNα. Additionally, the good tolerability of IFNβ represents an important advantage of the drug. The rates of dropouts in controlled clinical trials, as well as the need for dose reductions or treatment discontinuation are very low. It might be worth assessing the value of IFNβ plus ribavirin in randomized studies with a larger cohort of patients, not eligible or not tolerating standard therapy, and for non-responders.

Safety of interferon β treatment for chronic HCV hepatitis

Hepatitis C is a major cause of liver-related morbidity and mortality worldwide. In fact, chronic hepatitis C is considered as one of the primary causes of chronic liver disease, cirrhosis and hepatocellular carcinoma, and is the most common reason for liver transplantation. The primary objectives for the treatment of HCV-related chronic hepatitis is to eradicate infection and prevent progression of the disease. The treatment has evolved from the use of α -interferon (IFNα) alone to the combination of IFNα plus ribavirin, with a significant improvement in the overall efficacy, and to the newer PEG-IFNs which have further increased the virological response, used either alone or in combination with ribavirin. Despite these positive results, in terms of efficacy, concerns are related to the safety and adverse events. Many patients must reduce the dose of PEG-IFN or ribavirin, others must stop the treatment and a variable percentage of subjects are not suitable owing to intolerance toward drugs. IFNβ represents a potential therapeutic alternative for the treatment of chronic viral hepatitis and in some countries it plays an important role in therapeutic protocols. Aim of the present paper was to review available data on the safety of IFNβ treatment in HCV-related chronic hepatitis.

The rates of treatment discontinuation and/or dose modification due to the appearance of severe side effects during IFNβ are generally low and in several clinical studies no requirements for treatment discontinuation and/or dose modifications have been reported. The most frequent side effects experienced during IFNβ treatment are flu-like syndromes, fever, fatigue and injection-site reactions. No differences in terms of side-effect frequency and severity between responders and non-responders have been reported. A more recent study, performed to compare IFNβ alone or in combination with ribavirin, confirmed the good safety profile of both treatments. Similar trends of adverse event frequency have been observed in subpopulations such as patients with genotype-1b HCV hepatitis unresponsive to IFNα treatment or with HCV-related cirrhosis and patients with acute viral hepatitis. If further studies will confirm the efficacy of combined IFNβ and ribavirin treatment, this regimen could represent a safe and alternative therapeutic option in selected patients.

Different hepatitis C virus dynamics of free-virions and immune-complexes after initiation of interferon-alpha in patients with chronic hepatitis C

BACKGROUND/AIMS

To elucidate the mechanisms of action of interferon (IFN) against hepatitis C virus (HCV), we studied the serum HCV dynamics of free-virions (FV) and immune-complexes (IC) in patients treated with IFN.

METHODS

FV and IC were separated by immunoprecipitation using anti-human immunoglobulin and quantified serially using real-time detection-polymerase chain reaction.

RESULTS

Initially [1st phase (0-24 h)], the FV decreased more rapidly compared to IC [exponential decay slope (EDS)=1.78+/-0.42 vs. 0.99+/-0.31 log10/day, P<0.001; half-life=5.65+/-2.02 vs. 12.5+/-2.83 h, P<0.0001], but at the 2nd phase (1-14 days), half-life of FV was significantly longer than that of IC (101+/-117 vs. 14.2+/-1.08 h, P<0.005). Regarding response to IFN, the decline slope was not significantly different at the 1st phase, but at the 2nd phase, the FV-HCV RNA decreased more slowly in non-responders than in sustained responders to IFN (EDS=0.05+/-0.02 vs. 0.34+/-0.19 log10/day, P<0.005; half-life=186+/-112 vs. 15.3+/-1.85 h, P<0.005).

CONCLUSIONS

The presence of escape mutants from the neutralizing antibodies may be involved in resistance to IFN. Analyzes of FV- and IC-HCV dynamics are useful for predicting the IFN efficacy and understanding the mechanism of IFN action in chronic hepatitis patients.

Interferon-stimulated gene expression and hepatitis C viral dynamics during different interferon regimens

BACKGROUND/AIMS

To address the molecular mechanism for enhanced antiviral efficacy associated with a frequent dosing of interferon (IFN)-beta.

METHODS

Serum hepatitis C viral (HCV) dynamics, double-stranded RNA-activated protein kinase (PKR) mRNA and MxA mRNA levels in peripheral blood mononuclear cells (PBMC) were analyzed serially in 140 patients who were randomly assigned to a twice daily (3 MU bid) or once daily (6 MU qd) administration group.

RESULTS

In twice daily group, the rate of HCV decline during the second phase was 2-fold greater than in the once daily group (P=0.04). Peak PKR and MxA gene expression levels in the first phase (observed 4 h after a single administration) were 2-fold higher in the once daily group. However, the expression in the second phase was maintained at a significantly higher level in the twice daily group. Initial and peak expression levels were related to initial viral load. Basal expressions in PBMC were significantly correlated with those in the liver tissue (PKR, r=0.81; MxA, r=0.75, respectively, P<0.0001).

CONCLUSIONS

Our data suggest that elimination of HCV-infected cells is enhanced by twice daily dosing of IFN-beta, and that this enhanced effect is associated with a higher intracellular expression of PKR and MxA during the second phase.

Early hepatitis C viral kinetics correlate with long-term outcome in patients receiving high dose induction followed by combination interferon and ribavirin therapy

BACKGROUND/AIMS

The majority of patients with genotype 1 do not respond to interferon (IFN) plus ribavirin. Limited data exist on the use of induction followed by combination therapy.

METHODS

In this prospective study of 28 patients infected with genotype 1, randomization involved either daily or twice daily high dose IFN for 6 weeks, followed by standard therapy of 3 million units three times a week in combination with ribavirin for an additional 42 weeks. Hepatitis C virus (HCV) RNA was quantitated before and frequently during treatment.

RESULTS

The best correlate of response was delta (the infected cell loss rate). Sixteen patients continued on the study because they had at least a 2 log drop in their HCV RNA levels by week 12; all but one were PCR negative for HCV RNA at 48 weeks, and 14 of these 16 patients continued to be PCR negative at 72 weeks. Both African-Americans in our trial failed to respond to therapy, and differences were evident during the induction phase.

CONCLUSIONS

This randomized study of induction IFN therapy followed by combination IFN plus ribavirin yielded the highest rate of sustained response (50%) reported to date in chronically HCV-infected patients with genotype 1. The predictive value of the infected cell loss rate needs to be evaluated prospectively in larger studies, particularly in patients receiving pegylated IFN.

Treatment of chronic hepatitis C infection with cryoglobulinemia

Mixed cryoglobulinemia is characterized by a wide spectrum of manifestations that may vary from mild symptoms (such as purpura, arthralgias, and Raynaud phenomenon) to life-threatening conditions (such as acute abdomen, hyperviscosity syndrome, and renal involvement). Hepatitis C virus infection is considered the principal trigger of the disease. Therefore, the treatment not only should be tailored to the prevailing symptom but also take into account the presence of a chronic, often smoldering infection. Symptomatic therapies are to be used in cases of minor clinical manifestations and aggressive modalities in cases of life-threatening conditions. The use of aggressive cytotoxic regimens should actually be stopped and every potentially immunosuppressive drug should be used with caution. Antiviral medications are used with growing frequency. To date, a few small trials with interferon-alpha alone or in combination with ribavirin in mixed cryoglobulinemia have been conducted. This overview deals with the current approach to the management of mixed cryoglobulinemia, focusing in particular on antiviral treatment in hepatitis C virus infection with or without mixed cryoglobulinemia.

Dynamics of hepatitis C virus monitored by real-time quantitative polymerase chain reaction during first 2 weeks of IFN-beta treatment are predictive of long-term therapeutic response

The relation between the change in hepatitis C virus (HCV) RNA levels at the start of interferon-beta (IFN-beta) treatment and the long-term therapeutic response remains poorly defined. In 20 patients with chronic hepatitis C who received IFN-beta (total dose 126-756 MU), the changes in serum HCV RNA during the first 2 weeks of therapy were monitored by real-time quantitative polymerase chain reaction (PCR). The serum HCV RNA level decreased rapidly during the first 24 h of therapy (first phase) and more slowly thereafter (second phase), with a mean exponential decay rate of 1.17 log10/day and 0.37 log10/day, respectively. Three patients had a sustained virologic response, 10 patients had a transient response, and 7 patients had no response. The differences in the rate of first-phase viral decline among the three groups were not significant (p = 0.21), but the differences in the rate of second-phase viral decline were significant (p = 0.0021). The mean decay rate between the end of the first 24 h and day 14 was 0.96 +/- 0.43 log10/day in sustained responders, 0.39 +/- 0.30 log10/day in transient responders, and 0.13 +/- 0.09 log10/day in nonresponders. We conclude that during the first 2 weeks of therapy, changes in serum HCV RNA levels as monitored by real-time quantitative PCR can be used to predict the long-term response to treatment with IFN-beta.

The kinetics of hepatitis C virus infection

Mathematical modeling of viral dynamics reveals high turnover rates of pretreatment viral production and clearance (10(11)-10(13) virions/day) and permits the estimation of in-vivo half-lives of a few hours for HCV free virions. The balance between virus production and clearance in untreated patients with chronic hepatitis C virus results in a decline of viremia when active antiviral treatment is initiated. During the first phase of IFN-alpha therapy, the kinetics of the viral load is characterized by a rapid, dose-dependent decline. After about 24 to 48 hours, the viral decline enters a second phase of a relatively slow exponential decay during the following weeks of therapy which may reflect the death rate of infected hepatocytes. The second-phase decay is predictive for the virologic end-of-treatment status and, even more so, for the likelihood of sustained response. Nonresponding patients typically show constant viremia or even a rebound during this second phase.