Randomized, controlled trial with IFN-alpha combined with ribavirin with and without amantadine sulphate in non-responders with chronic hepatitis C

New use of an old drug: chloroquine reduces viral and ALT levels in HCV non-responders (a randomized, triple-blind, placebo-controlled pilot trial)

Hepatitis C virus (HCV) infection induces autophagy, but the virus assimilates the autophagic response into its own life cycle. Chloroquine (CQ) is an autophagy inhibitor that is clinically used to treat malaria. The aims of this pilot clinical trial were to evaluate the therapeutic potential and short-term safety of CQ in patients with chronic HCV genotype 1, who were unresponsive to a combination of pegylated interferon alpha and ribavirin. Ten non-responders to previous antiviral treatment(s) were randomized to receive either CQ (150 mg daily for 8 weeks) or placebo, and were followed for 4 weeks after CQ therapy. HCV RNA load and plasma alanine transaminase (ALT) levels were measured at baseline, week 4 (initial response), week 8 (end-of-treatment response), and at the end of 12 weeks. A significant decrease in HCV RNA after the treatments (week 8) was observed in all patients in the CQ group (P = 0.04). However, HCV RNA levels increased within 4 weeks after discontinuation of CQ treatment although they were still lower than baseline. In addition, the ALT normalized during treatment in the CQ group. However, this response was also lost after treatment cessation. This study provides preliminary evidence that CQ is possibly a safe treatment option for HCV non-responders.

Aminoadamantanes for chronic hepatitis C

BACKGROUND

Around 3% of the world's population (approximately 160 million people) are chronically infected with hepatitis C virus. The proportion of infected people who develop clinical symptoms varies between 5% and 40%. Combination therapy with pegylated interferon-alpha plus ribavirin eradicates the virus from the blood six months after treatment (sustained virological response) in approximately 40% to 80% of infected patients, depending on the viral genotype. New antiviral agents, such as boceprevir and telaprevir, in combination with standard therapy, can increase sustained virological response in genotype 1 infected patients to at least 70%. There is therefore an unmet need for drugs that can achieve a higher proportion of sustained virological response. Aminoadamantanes are antiviral drugs used for treatment of patients with chronic hepatitis C.

OBJECTIVES

To assess the beneficial and harmful effects of aminoadamantanes for patients with chronic hepatitis C infection by conducting a systematic review with meta-analyses of randomised clinical trials, as well as trial sequential analyses.

SEARCH METHODS

We conducted electronic searches of the Cochrane Hepato-Biliary Group Controlled Trials Register (1996 to December 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 11 of 12 (1995 to December 2013), MEDLINE (1946 to December 2013), EMBASE (1974 to December 2013), Science Citation Index EXPANDED (1900 to December 2013), the WHO International Clinical Trials Registry Platform (www.who.int/ictrp), Google Scholar, and Eudrapharm up to December 2013 and checked the reference lists of identified publications.

SELECTION CRITERIA

Randomised clinical trials assessing aminoadamantanes in patients with chronic hepatitis C infection.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. We assessed for risks of systematic errors ('bias') using the 'Risk of bias' tool. We analysed dichotomous data with risk ratio (RR) and continuous data with mean difference (MD) or standardised mean difference (SMD), both with 95% confidence intervals (CI). We used trial sequential analysis to assess the risk of random errors ('play of chance'). We assessed quality using the GRADE system.

MAIN RESULTS

We included 41 randomised clinical trials with 6193 patients with chronic hepatitis C. All trials had high risk of bias. All included trials compared amantadine versus placebo or no intervention. Standard antiviral therapy was administered equally to the intervention and the control groups in 40 trials. The standard antiviral therapy, which was administered to both intervention groups, was interferon-alpha, interferon-alpha plus ribavirin, and peg interferon-alpha plus ribavirin, depending on the time when the trial was conducted.When we meta-analysed all trials together, the overall results demonstrated no significant effects of amantadine, when compared with placebo or no intervention, on our all-cause mortality or liver-related morbidity composite outcome (5/2353 (0.2%) versus 6/2264 (0.3%); RR 0.90, 95% CI 0.38 to 2.17; I² = 0%; 32 trials; very low quality). There was also no significant effect on adverse events (288/2869 (10%) versus 293/2777 (11%); RR 0.98, 95% CI 0.84 to 1.14; I² = 0%; 35 trials; moderate quality). We used both fixed-effect and random-effects meta-analyses. Amantadine, when compared with placebo or no intervention, did not significantly influence the number of patients who failed to achieve a sustained virological response (1821/2861 (64%) versus 1737/2721 (64%); RR 0.98, 95% CI 0.95 to 1.02; I² = 35%; 35 trials; moderate quality). However, in the subgroup using interferon plus ribavirin, amantadine decreased the number of patients who failed to achieve a sustained virological response (422/666 (63%) versus 447/628 (71%); RR 0.89, 95% CI 0.83 to 0.96; I² = 41%; 11 trials; low quality). Similar results were found for failure to achieve an end of treatment virological response. Amantadine, when compared with placebo or no intervention, significantly decreased the number of patients without normalisation of alanine aminotransferase (ALT) serum levels at the end of treatment (671/1141 (59%) versus 732/1100 (67%); RR 0.88, 95% CI 0.83 to 0.94; I² = 47%; 19 trials; low quality). Amantadine, when compared with placebo or no intervention, did not significantly influence the end of follow-up biochemical response (1133/1896 (60%) versus 1151/1848 (62%); RR 0.95, 95% CI 0.91 to 1.00; I² = 49%; 21 trials; low quality).The observed beneficial effects could be true effects but could also be due to both systematic errors (bias) and random errors (play of chance). The latter is due to the fact that trial sequential analyses could not confirm or refute our findings. We were not able to perform meta-analyses for failure of histological improvement or quality of life due to a lack of valid data.

AUTHORS' CONCLUSIONS

This systematic review does not demonstrate any significant effects of amantadine on all-cause mortality or liver-related morbidity composite outcome and on adverse events in patients with hepatitis C; however, the median trial duration was 12 months, with a median follow-up of six months, which is not long enough to assess the composite outcome sufficiently. Overall, we did not see an effect of amantadine on failure to achieve a sustained virological response. Subgroup analyses demonstrated that the combination of amantadine plus interferon-alpha and ribavirin seems to increase the number of patients achieving a sustained virological response. This finding may be caused by both systematic errors (bias) and risks of random errors (play of chance), but it could also be real. Based on the results of the overall evidence, it appears less likely that future trials assessing amantadine for patients with chronic hepatitis C will show strong benefits. Therefore, it is probably advisable to wait for the results of trials assessing other direct-acting antiviral drugs. In the absence of convincing evidence of benefit, the use of amantadine is justified in the context of randomised clinical trials assessing the effects of combination therapy. We found a lack of evidence on other aminoadamantanes than amantadine.

Influence of amantadine on CD81 expression on lymphocytes in chronic hepatitis C

INTRODUCTION

Interferon alpha (IFN) down regulates CD81 expression on peripheral blood mononuclear cells (PBMC) in patients with chronic hepatitis C virus (HCV) infection. Aim of our study was to investigate whether amantadine alters IFN associated down regulation of CD81 expression on PBMC in patients with chronic hepatitis C.

METHODS

Nineteen patients with chronic HCV infection received peginterferon alpha-2a/ribavirin (SOC) for 48 weeks. Patients were randomised to 12 weeks amantadine therapy (n=12) or no additional treatment (n=7). FACS analysis of CD81 expression on CD4(+), CD8(+), CD19(+), and CD56(+) cells was performed at baseline, week (TW) 4, TW12, and TW24 of antiviral therapy.

RESULTS

A significant decline of CD81 expression was observed on CD4(+), CD8(+), and CD56(+) cells (p=0.011, p<0.001, p=0.015, respectively) but not on CD19(+) cells (p>0.2). CD81 expression on CD4(+), CD8(+), CD19(+), and CD56(+) cells was not different between patients treated with SOC plus amantadine and patients treated with SOC alone.

CONCLUSION

The current study confirms that CD81 expression is down regulated by SOC on CD4(+), CD8(+) and CD56(+) cells. Amantadine treatment was not associated with CD81 expression. Interaction between amantadine and CD81 is unlikely to be involved in potential antiviral activity of amantadine in chronic HCV infection.

No beneficial effects of amantadine in treatment of chronic hepatitis C patients

BACKGROUND

Benefit of adding amantadine to antiviral therapy for hepatitis C is controversial.

AIMS

We aimed to examine whether such policy enhances sustained viral response in treatment-naïve patients.

METHODS

297 naïve hepatitis C patients were randomized for treatment with amantadine 200mg or placebo, combined with weight-based ribavirin and 12-day high-dose interferon alpha-2b induction therapy, followed by PEG-interferon alpha-2b (1.5 microg/kg/week up to 26 weeks and thereafter, 1.0 microg/kg/week until week 52). Treatment was discontinued if hepatitis C virus (HCV) RNA was positive at week 24.

RESULTS

49% of patients were (former) drug users. Genotype 1 occurred in 45%, high viral load in 70% and severe fibrosis/cirrhosis in 32%, without differences between amantadine or placebo groups. 90 patients prematurely discontinued treatment, mainly because of grade 3 or 4 toxicity. Intention-to-treat analysis revealed sustained viral response in 47% and 51% of amantadine and placebo groups (p=0.49). Amantadine did not enhance sustained viral response in patients with genotype 1 or high viral load nor did it improve primary non-response, breakthrough or relapse rates. Genotype non-1 and lower pre-treatment gamma GT levels were independent predictors for sustained viral response.

CONCLUSION

Adding amantadine to antiviral therapy of previously untreated chronic hepatitis C patients has no beneficial effects.

Clinical trial: a randomized trial of pegylated-interferon-alpha-2a plus ribavirin with or without amantadine in treatment-naïve or relapsing chronic hepatitis C patients

BACKGROUND

The combination therapy of pegylated-interferon-alpha2a plus ribavirin is considered as the standard of care for patients with chronic hepatitis C. A sustained viral response is obtained in 40-50% of naïve patients with genotype 1 and in around 80% of naïve patients with genotype 2 or 3.

AIM

To assess whether amantadine, added to the conventional combination therapy, could improve the treatment efficacy.

METHODS

In all, 630 patients (intent-to-treat population) with chronic hepatitis C were randomized into two groups: 316 patients (treatment group) received pegylated-interferon-alpha2a (180 microg once weekly) plus ribavirin (1000-1200 mg/daily) with amantadine (200 mg/daily); 314 patients (control group) received pegylated-interferon-alpha2a (180 microg once weekly) plus ribavirin (1000-1200 mg/daily) without amantadine. The duration of the treatment was 48 weeks for genotypes 1, 4, 5 and 6, and 24 weeks for genotypes 2 and 3.

RESULTS

There was no statistically significant difference between treatments groups for any of the variables tested for. Subgroups of patients likely to take advantage of the addition of amantadine were not identified.

CONCLUSIONS

This large study definitely excludes the role of amantadine in addition of conventional combination therapy in the treatment of chronic hepatitis C patients.

Placebo-controlled trial of 400 mg amantadine combined with peginterferon alfa-2a and ribavirin for 48 weeks in chronic hepatitis C virus-1 infection

The impact of amantadine on virologic response rates of interferon-based treatment of chronic hepatitis C is controversial. The aim of this study was to compare virological response rates in patients with chronic hepatitis C virus (HCV)-1 infection treated with 400 mg amantadine or placebo in combination with peginterferon alfa-2a (40 kD) and ribavirin for 48 weeks. Seven hundred four previously untreated chronically HCV-1-infected patients (mean age, 46 +/- 12 years) were randomized to (A) amantadine-sulphate (400 mg/day) (n = 352) or (B) placebo (n = 352), both in combination with 180 microg peginterferon alfa-2a once weekly and ribavirin (1000-1200 mg/day) for 48 weeks. End of treatment and sustained virological response after a 24-week follow-up period were assessed by qualitative reverse transcription polymerase chain reaction (RT-PCR) (sensitivity, 50 IU/mL). Demographic and baseline virological parameters were similar in both treatment groups. In groups A and B, 231 of 352 patients (66%) and 256 of 352 patients (72%) achieved an end of treatment response, and 171 of 352 patients (49 %) and 186 of 352 patients (53 %) a sustained virological response, respectively. On-treatment dropout rate in the amantadine group was significantly higher than in the placebo group (32% versus 23%; P = 0.01). However, adverse events and laboratory abnormalities were similar between both groups. Per-protocol analysis revealed similar sustained virological response rates in both treatment groups (53% versus 55%).

CONCLUSION

In this large placebo-controlled multicenter study, amantadine even at a dose of 400 mg/day did not improve virological response rates of peginterferon alfa-2a and ribavirin in patients with chronic genotype HCV-1 infection.

Approach to the management of patients with chronic hepatitis C who failed to achieve sustained virologic response

The combination of PEGIFN and RBV is the most effective therapy for patients with chronic hepatitis C. Although more than half of all patients are able to achieve SVR, a significant proportion of patients, particularly those with genotype 1, fail to have undetectable HCV RNA during treatment or relapse after completing therapy with return of detectable HCV RNA. An approach in the management of these patients is to identify factors that could have led to the NR or relapse and that could be corrected before or during a second course of therapy. Because fibrosis progression occurs slowly over decades for many patients with chronic hepatitis C, avoiding alcohol or other factors that could lead to fibrosis progression may be sufficient for the vast majority of patients. Other options that could be considered in patients who have more advanced disease include retreating with one of several new antiviral agents; retreating with higher doses of IFN or PEGIFN and RBV; or using IFN, PEGIFN, or RBV monotherapy long-term as maintenance therapy. The safety and efficacy of these approaches is being evaluated in numerous clinical trials.

Efficacy of amantadine on quality of life in patients with chronic hepatitis C treated with interferon-alpha and ribavirin: results from a randomized, placebo-controlled, double-blind trial

AIM

The aim of this study was to investigate whether amantadine reduces deterioration of quality of life in patients with chronic hepatitis C during and after treatment with interferon-alpha (IFN-alpha) and ribavirin.

PATIENTS AND METHODS

In this randomized, prospective, placebo-controlled, multicenter trial, previously untreated patients with chronic hepatitis C were treated with IFN-alpha plus ribavirin [17] and randomized for treatment with amantadine (200 mg/day, orally, n=136) or placebo (n=131). Quality of life was assessed with the 'Profile of Mood States' scale and the 'Everyday Life' questionnaire at baseline, treatment week (TW) 8, TW24, TW48, and at follow-up.

RESULTS

Early during treatment at TW8, quality of life was not different between patients in the control and the amantadine group. At TW24, the control group but not the amantadine group, however, showed significant deterioration of the modalities depression, fatigue, and vigor compared with baseline. Especially, nonresponders in the amantadine group showed significantly lower deterioration of depression, anger, mind function, everyday life, and zest for life than those in the placebo group. After treatment, the beneficial effects of amantadine disappeared.

CONCLUSION

The addition of amantadine to IFN-alpha plus ribavirin combination therapy may reduce deterioration of depression, fatigue, and vigor during treatment but does not affect quality of life after treatment.

A randomized trial of induction doses of interferon alone or in combination with ribavirin or ribavirin plus amantadine for treatment of nonresponder patients with chronic hepatitis C

BACKGROUND

Efficacy and safety of interferon induction therapy alone or in combination with ribavirin or ribavirin plus amantadine were evaluated in chronic hepatitis C patients who were nonresponders to primary antiviral treatment.

METHODS

The study was designed to have 225 HCV nonresponder patients, but at an interim analysis the response rate difference between groups was lower than expected and the enrollment was stopped when 75 patients had been randomized to receive interferon-alpha2a (group A, n = 26), interferon-alpha2a plus 15 mg/kg per day of ribavirin (group B, n = 24), or interferon-alpha2a plus ribavirin plus 200 mg/day of amantadine hydrochloride (group C, n = 25). Treatment duration was 48 weeks. The dose of interferon was 6 MU/day for 4 weeks followed by 3 MU/day for the remaining 44 weeks.

RESULTS

On intention-to-treat, the sustained virological response at 24 weeks of follow-up was 11.5% in group A, 12.5% in group B, and 12% in group C. Therapy was discontinued because of adverse effects in three patients in group A (11.5%), three in group B (12.5%), and two in group C (8%).

CONCLUSIONS

Nonresponders with chronic hepatitis C may achieve a sustained virological response rate of approximately 12% if retreated with interferon induction treatment followed by administration of a daily dose. The addition of ribavirin or amantadine did not seem to improve the response rates.

Treatment of hepatitis C virus infection

Acute and chronic hepatitis C virus (HCV) infection remains a serious health problem worldwide, however, there has been advancement in the treatment of HCV infection due to standard treatment using pegylated interferon and ribavirin. The literature indicates that therapy for HCV is becoming more individualized. In addition to considering genotype and viral RNA levels before treatment, achievement of an early virologic response (EVR) and a rapid virologic response (RVR) is now possible during therapy. Moreover, problem patients, such as non-responders, relapsers, HIV or HBV co-infected patients, patients with liver cirrhosis, and pre- or post-liver transplantation patients are an increasing fraction of the patients requiring treatment. This article reviews the literature regarding standard treatments and problem patients with acute and chronic HCV infection. It also includes discussion on contraindications and side effects of treatment with interferon and ribavirin, as well as new drug development.

High predictive value of early viral kinetics in retreatment with peginterferon and ribavirin of chronic hepatitis C patients non-responders to standard combination therapy

BACKGROUND/AIMS

To evaluate the efficacy of peginterferon alfa-2b and ribavirin in unselected consecutive patients with chronic hepatitis C, treated outside of trials, who were relapsers or non-responders to interferon and ribavirin combination.

METHODS

One hundred and fifty-four patients were evaluated. There were 101 non-responders and 53 relapsers to standard combination therapy. Patients were retreated with peginterferon alfa-2b 1.5 microg/kg/wk plus ribavirin 1000-1200 mg/day during 48 weeks.

RESULTS

Forty-four patients (28.6%) achieved sustained virological response (SVR). Rapid (week 4) and early (week 12) virological response had high negative predictive values of SVR (94% and 97%, respectively); however positive predictive values were relatively low (52% and 49%, respectively). Relapsers had higher SVR rates (58.5%) than non-responders (13%) p<0.0001. In non-responders, SVR raised to 50% in patients with genotype non-1 and mild or moderate fibrosis. In multivariate analysis, predictors of SVR were: relapse after interferon plus ribavirin combination, mild or moderate fibrosis, genotype non-1 and baseline viral load <2 million copies/ml.

CONCLUSIONS

Relapsers to interferon plus ribavirin therapy, and non-responders with genotype non-1 and mild or moderate fibrosis, achieved a relatively high SVR rate following retreatment with peginterferon plus ribavirin. Early viral kinetics had a high negative predictive value of SVR.

Viral determinants of resistance to treatment in patients with hepatitis C

Chronic hepatitis C virus (HCV) infection affects more than 170 million persons worldwide and is responsible for the development of liver cirrhosis in many cases. Standard treatment with pegylated alpha interferon (IFN-alpha) in combination with the nucleoside analogue ribavirin leads to a sustained virologic response in approximately half of the patients. IFN-alpha is classified as an indirect treatment, as it interacts with the host's immune response. The mechanism of action of ribavirin is still unknown. The benefit of triple therapy by adding other antiviral agents, e.g., amantadine, is controversial. Currently, new direct antiviral drugs (HCV protease/polymerase inhibitors) are being evaluated in phase 1/phase 2 trials. Phenotypic resistance to antiviral therapy has been attributed to amino acid variations within distinct regions of the HCV polyprotein. While sensitivity to IFN-alpha-based antiviral therapy in vivo is clearly correlated with the number of mutations within the HCV NS5A protein, the underlying functional mechanisms for this association are unknown. In turn, in vitro, several mechanisms to circumvent the host immune defense or to block treatment-induced antiviral activities have been described for different HCV proteins. By the introduction of direct antiviral drugs, hepatitis C therapy now is entering a new era in which the development of resistance may become the most important parameter for treatment success or failure.

Induction doses of interferon-alpha-2a in combination with ribavirin and/or amantadine for the treatment of chronic hepatitis C in non-responders to interferon monotherapy: a randomized trial

The benefit of the triple therapy (interferon + amantadine + ribavirim) is still unknown. The efficacy of induction doses of interferon-alpha-2a monotherapy or in combination with ribavirin and/or amantadine was evaluated in interferon non-responders with chronic hepatitis C. A total of 378 patients were randomized. All the groups received the same doses and duration of interferon-alpha-2a: (i) interferon 9 MUI/day for 4 weeks and then 3 MUI/3 t.i.w. for 44 weeks (n = 53); (ii) interferon in combination with amantadine 100 mg twice daily for 48 weeks (n = 111); (iii) interferon in combination with ribavirin 1000-1200 mg (n = 106); (iv) interferon in combination with amantadine and ribavirin (n = 108). Baseline parameters were similar in the four groups. Sustained virological and biochemical responses were 13%, 6%, 18% and 22% respectively. No significant differences were found between double ribavirin arm vs triple therapy, but the difference was significant between interferon-amantadine (P = 0.008) and triple therapy (P = 0.0005). Hence, the induction doses of interferon in combination with ribavirin or ribavirin plus amantadine showed encouraging results in patients with chronic hepatitis C who were resistant to interferon. However, triple therapy is not superior to double.

Efficacy and safety of peg-IFN alfa-2a with ribavirin for the treatment of HCV/HIV coinfected patients who failed previous IFN based therapy

BACKGROUND

Interferon (IFN) regimens for HCV treatment are less effective in HCV/HIV-coinfected patients. There are no effective treatments for patients who fail IFN therapies. We examined the safety and efficacy of peginterferon alfa-2a (peg-IFNalpha-2a) plus ribavirin (RBV) in 41HCV/HIV-coinfected patients non-responsive to prior IFN treatment.

METHODS

Patients received peg-IFNalpha-2a (180mg/week) plus RBV (800mg/day) for 24 weeks (n=41). At week 24, patients with non-detectable HCV RNA or > or =2-log decrease from baseline, received peg-IFNalpha-2a (180mg/week) plus RBV (800mg/day) for 24 weeks further. Patients not responding to treatment at week 24 were discontinued.

RESULTS

Intent to treat (ITT) sustained viral response (SVR) was 21.9%. Patients who received at least 24 weeks of peg-IFNalpha-2a plus RBV treatment (n=35), SVR rates were 25.7%. SVR was associated with significant improvements in liver histology grade (p=0.02), stage (p=0.02), and fibrosis progression rate (FPR) (p=0.03). Patients that failed to achieve SVR had statistically significant decreases in grade (p=0.09) and FPR (p=0.01).

CONCLUSION

peg-IFNalpha-2a plus RBV is effective and safe to achieve SVR in HCV/HIV coinfected patients non-responsive to prior IFN treatment. Patients that achieve SVR have significant improvements in liver histology parameters. In patients that do not achieve SVR there are histological benefits beyond virological response that suggest that peg-IFNalpha-2a+RBV therapy may decrease risk of progression to end stage liver disease.

A randomized trial of pegylated-interferon-alpha2a plus ribavirin with or without amantadine in the re-treatment of patients with chronic hepatitis C not responding to standard interferon and ribavirin

BACKGROUND

There is yet no established treatment for chronic hepatitis C patients non-responder to standard interferon and ribavirin.

AIM

To evaluate efficacy and safety of pegylated-interferon-alpha2a plus ribavirin with or without amantadine in such patients.

METHODS

161 non-responders to standard interferon and ribavirin were randomized into two groups: 81 patients (Group 1) were given weekly Peg-IFN-alpha2a 180 microg plus ribavirin 1,000-1,200 mg/daily for 12 months, 80 patients (Group 2) received weekly Peg-IFN-alpha2a 180 microg plus ribavirin 1,000-1,200 mg/daily and amantadine 200 mg/daily for 12 months.

RESULTS

At the end of follow-up, HCV-RNA was negative in 29.6% of Group 1 and in 21.2% of Group 2 patients (P = 0.22). Patients with genotypes 1 and 4 responded better to bi-therapy (21.7%) than to triple therapy (17.3%, P = 0.5) while among patients with genotypes 2 and 3 there was a trend towards a higher sustained virological response rate when retreated with triple treatment (80% vs. 75%, P = 0.82). On multivariate analysis, genotype 1 or 4, high body mass index and >20% reduction of Peg-interferon were associated with the treatment failure.

CONCLUSIONS

The addition of amantadine does not improve the overall SVR rate in non-responder patients retreated with Peg-IFN and ribavirin; however, about 30% of non-responders may achieve a sustained response, in particular patients with genotypes 2 and 3 show a high SVR (75%).

Triple antiviral therapy in HCV positive patients who failed prior combination therapy

AIM: To assess the efficacy of triple therapy (peginte-rferon or high dose standard interferon, plus ribavirin and amantadine) in nonresponders to prior combination therapy.

METHODS: A total of 196 patients were enrolled in a multicenter, open, randomized study. Patients were given 180 μg/wk of peginterferon-alpha-2a (40 kDa) plus ribavirin (800-1000 mg/d) and amantadine (200 mg/d) for 48 wk (group A) or interferon-alpha-2a (6 MU/d for 4 wk, 3 MU/d for 20 wk, and 3 MU tiw for 24 wk) plus ribavirin (800-1000 mg/d) and amantadine (200 mg/d) for 48 wk (group B).

RESULTS: Overall sustained virologic response (SVR) was 26.6% (32.1% and 19.5% in group A and B, P = 0.057). Baseline ALT >120 UI/L (OR 2.4; 95% CI:1.11 to 5.20; P = 0.026) and HCV RNA negativity after 12 wk (OR 8.7; 95% CI: 3.87 to 19.74; P < 0.0001) were independently associated with SVR. Therapy discontinuation occurred less frequently in patients treated with peginterferon than standard interferon (P = 0.036).

CONCLUSION: More than 25% of nonresponders to combination therapy can eradicate HCV infection when retreated with triple therapy, especially if they have a high baseline ALT and are treated with pegylated interferon.

Amino Acid Variations in Hepatitis C Virus P7 and Sensitivity to Antiviral Combination Therapy with Amantadine in Chronic Hepatitis C

Background

Formation of transmembrane ion channels by hepatitis C virus (HCV) p7 and abrogation of channel function by amantadine was demonstrated in vitro. The relevance of HCV p7 amino acid (aa) variations for response to antiviral therapy with amantadine is unknown.

Methods

HCV p7 was sequenced in 86 individuals who were infected with HCV genotype 1. Thirty-six of 86 patients received amantadine within an interferon-α (IFN-α)-based antiviral therapy. Helical wheel modelling for HCV p7 was performed.

Results

No significant correlation of overall aa variations within HCV p7 was observed with response to IFN-α-based therapy with amantadine in HCV genotype 1a/b infected patients. When analysis was restricted to non-conservative aa variations, a higher number of aa substitutions within complete HCV p7 and transmem-brane helix 2 was associated with non-response in HCV-1b-infected patients receiving therapy with amantadine ( P=0.015 and P=0.037, respectively), without amantadine ( P=0.106 and P=0.118, respectively), and in the total cohort of HCV-1b-infected patients ( P=0.00007 and P=0.011, respectively). Furthermore, substitution L20F was observed more often in non-responders than responders with HCV-1b infection and therapy with amantadine ( P=0.099). By in silico modelling, aa 20 was located toward the p7 channel lumen. Substitution L20F may impair amantadine action by altering the shape of the ion channel pore.

Conclusion

Substitution L20F within HCV p7 may be associated with non-response to combination therapy specifically with amantadine in HCV-1b-infected patients. Non-responders with HCV-1b infection showed higher numbers of non-conservative aa variations within HCV p7 than responders, irrespective of the application of amantadine.

Amantadine triple therapy for non-responder hepatitis C patients. Clues for controversies (ANRS HC 03 BITRI)

BACKGROUND/AIMS

To determine whether addition of amantadine to pegylated interferon/ribavirin improved response rates among chronic hepatitis C patients, non-responders to interferon/ribavirin and study the dynamic of response.

METHODS

In a double blind, multicenter, randomized trial, 200 non-responder patients received pegylated interferon 1.5 microg/kg per week and ribavirin 800-1200 mg/day, plus either amantadine 200 mg/day or placebo for 48 weeks. Endpoints were virological responses, ALT normalization, and histological benefit overtime.

RESULTS

Twenty percent of all patients achieved a sustained virological response (SVR). This rate was 8% higher in the triple therapy group (24%) compared with the double therapy group (16%) (P = 0.22). A better virological response rate at week 24 was observed in the triple regimen group (43 vs 29%; P = 0.06), which was lost at week 48 suggesting viral escape. The biochemical response rate was also significantly higher with triple therapy at week 12 (63 vs 49%; P = 0.05) and week 24 (64 vs 49%; P = 0.03). Fibrosis stabilized or improved in 77% of all patients.

CONCLUSIONS

Re-treatment of interferon/ribavirin non-responder patients should be encouraged since a substantial proportion benefits from re-treatment with pegylated interferon/ribavirin +/- amantadine. In triple therapy involving amantadine, a time wise response and an increased SVR rate in subgroups less prone to viral breakthrough suggest clues for existing controversies.

Randomized, double-blind, placebo-controlled study of peginterferon alfa-2a (40KD) plus ribavirin with or without amantadine in treatment-naïve patients with chronic hepatitis C genotype 1 infection

BACKGROUND/AIMS

Amantadine may augment virological response rates to interferon-based therapy in chronic hepatitis C patients. Using a novel design, amantadine was studied in naïve genotype 1 patients treated in combination with peginterferon alfa-2a (40KD)/ribavirin.

METHODS

Patients enrolled in this randomized, placebo-controlled multicenter trial were stratified by single-dose interferon sensitivity (stratum I, 24-h HCV-RNA decline >1.4-log10; II, 0.8-1.39-log10; III, <0.8-log10; a reliable means of identifying nonresponders to interferon/ribavirin) and fibrosis grade (F0/1/2 vs. F3/4) at baseline. All patients received peginterferon alfa-2a (40KD) 180 microg/week plus ribavirin 1000-1200 mg/day and were randomized to receive amantadine 100 mg twice daily (N = 114) or placebo (N = 95) for 48 weeks.

RESULTS

Week-24 virological response rates in strata II and III, the primary outcome, were similar in patients treated with amantadine (63.7%) or placebo (65.7%), as were sustained virological response rates at week 72 (46.5 and 51.6%, respectively). Adverse event profiles were similar and amantadine did not improve health-related quality of life compared with placebo. Interferon sensitivity was the only significant predictor of treatment outcome.

CONCLUSIONS

Adding amantadine to peginterferon alfa-2a (40KD)/ribavirin combination therapy does not augment virological response rates in genotype 1 patients. Virological response was almost exclusively determined by interferon sensitivity at baseline.

Amantadine in treatment of chronic hepatitis C virus infection?

SUMMARY

Treatment of chronic hepatitis C (CHC) continues to be an important and growing challenge. As the response rate to FDA-approved treatment improved over the past decade, we are facing increasing number of difficult-to-treat patients such as those who have failed prior anti-viral therapy. The role of amantadine in the treatment of CHC remains unclear. Studies thus far have produced conflicting results, and type II error could not be excluded. This review summarized results published in the literature from 1997 to 2003, and reviewed the existing questions and controversies regarding the use of amantadine. Current literature suggests that amantadine is ineffective as monotherapy. Amantadine increased the sustained virologic response of certain treatment naïve patients when used in combination with interferon, and may be effective as an adjunct to interferon-based combination therapy in some patients who have failed or relapsed on prior therapy. Factors such as small sample size, patient characteristics, and differences in treatment protocols including amantadine preparation and duration of therapy might explain the conflicting observations of various studies. Further investigations are needed to define optimal dosing and formulation of amantadine, and its appropriate role in management of CHC infection.

Approach to the management of patients with chronic hepatitis C who failed to achieve sustained virologic response

The combination of peginterferon and ribavirin is the most effective therapy for patients with chronic hepatitis C virus (HCV) infection. Although more than half of all patients are able to achieve a sustained virologic response (SVR), a significant proportion of patients, particularly those with genotype 1, fail to have undetectable HCV RNA during treatment or relapse after completing therapy with return of detectable HCV RNA. The management of these patients creates a formidable challenge. This article outlines various strategies for patients who have failed to achieve SVR and discusses the merits of different approaches to management.

Treatment of hepatitis C

The combination of pegylated interferon alpha and ribavirin has improved treatment success rates in patients with hepatitis C with sustained response rates of just over 50% overall and more than 70% for those with genotypes 2 and 3. This article reviews the use of combination therapy, contraindications, factors influencing response and describes approaches to specific patient groups.

Recent developments in target identification against hepatitis C virus

Chronic hepatitis C is a leading cause of liver cirrhosis and hepatocellular carcinoma worldwide. Recent progress in the understanding of the molecular virology of hepatitis C has allowed the identification of novel antiviral targets. Moreover, in vitro and in vivo model systems have been developed that allow the systematic evaluation of new therapeutic strategies. Exciting results from proof-of-concept clinical studies have now been reported for a specific hepatitis C virus serine protease inhibitor. These and other novel antiviral strategies may complement existing therapeutic modalities in the future.

Retreatment of patients with chronic hepatitis C not responding to interferon/ribavirin combination therapy with daily interferon plus ribavirin plus amantadine

There is currently no accepted therapeutic regimen for patients with chronic hepatitis C who failed to respond to standard combination treatment with interferon-alpha plus ribavirin. We investigated triple combination treatment with induction dosing of interferon-alpha plus ribavirin plus amantadine in these difficult-to-treat patients. Nonresponders (n = 67), breakthroughs (n = 16) and relapsers (n = 19) to previous interferon/ribavirin combination treatment of at least 6 months were included. For the first 16 weeks, patients received interferon-alpha2a 6 MU daily, ribavirin 800-1200 mg/d, and amantadine 200 mg/d. In cases of undetectable HCV RNA at week 12, treatment was continued with interferon-alpha2a 6 MU every other day and the same doses of ribavirin and amantadine until week 48. In cases of HCV RNA positivity at week 12, treatment was stopped. A total of 102 patients were enrolled (80%: genotype 1, 19%: cirrhosis). HCV RNA was negative in 35/102 patients (34%) at week 12 and in 27/ 102 patients (26%) at the end of treatment. Virological response was sustained in 15/102 patients (15%). On-treatment virological response was higher in previous relapsers/breakthroughs than in previous nonresponders (week 12: 49% vs. 27%, p < 0.05; week 48: 46% vs. 16%, p < 0.01) but no such difference was found for sustained virological response (20% vs. 12%, NS). In conclusion, triple combination treatment with daily interferon-alpha plus ribavirin plus amantadine for 3 months can induce virological response in a considerable number of nonresponders/relapsers to previous dual combination treatment, but the sustained virological response rate remains low.

Nonresponders to Previous Chronic Hepatitis C Treatment

The main strategy governing treatment of chronic hepatitis C is the prevention of future liver complications. There is good evidence that curing hepatitis C infection prevents progression of liver disease and allows histologic regression to occur. Therefore, the primary goal of medical treatment is to cure the viral infection. Combination therapy with peginterferon alfa and ribavirin is the current standard of care; there are no other medical therapies currently available. Those who failed to respond to an earlier version of antiviral therapy should strongly consider treatment with peginterferon/ribavirin if possible. Nearly half of patients who start peginterferon/ribavirin are unable to achieve a sustained disappearance of infection. If there were problems related to dosing or adherence the first time around, it is reasonable to consider re-treating with more aggressive support. Nonresponders to the current therapy who have early-stage liver disease can afford to wait until new antiviral agents come along in the next 5 to 10 years. However, physicians should encourage nonresponding patients with advanced fibrosis to consider experimental alternatives in the meantime, provided there is a logical rationale for the treatment proposed. Some re-treatment strategies still aim to cure the hepatitis C virus infection whereas others focus on limiting liver damage. The best candidates for the first strategy are patients who had temporary clearance of the virus during previous treatment and those with hepatitis C virus genotype 2 or 3 infection. Logical candidates for the second strategy are those who already have advanced fibrosis. It is preferable to pursue further attempts at treatment within the framework of a controlled trial. Studies with strong rationales include those investigating high-dose peginterferon/ribavirin, long-term peginterferon suppression, potential immune modulators, and potential inhibitors of liver fibrosis. The rationales are weaker for re-treatment with a second brand of peginterferon/ribavirin, daily standard interferon plus ribavirin, and ribavirin monotherapy.

Management of chronic hepatitis C virus infection: a new era of disease control

The management of chronic viral hepatitis has changed significantly with the availability of effective antiviral agents. There is now a high probability that timely intervention can arrest development of cirrhosis, thereby preventing mortality from portal hypertension, liver failure and liver cancer. This two-part review discusses the implications of this new era of antiviral therapy for physicians. The present review is about chronic hepatitis C virus (HCV); a similar review that considers the treatment of hepatitis B virus will be published in a later issue of the Internal Medicine Journal. Chronic HCV infection is common, but fibrotic progression of liver disease is slow and variable; many infected persons never develop cirrhosis. Case selection for antiviral therapy is crucial. The most effective therapy is a pegylated (long-acting) interferon with ribavirin. Sustained viral response (SVR) (absent viraemia 6 months after completing treatment) can be obtained in 40-60% of individuals infected with genotype 1 and in approximately 67% with genotype 4 after 12 months of treatment. Response rates are higher (75-85%) with genotypes 2 and 3 after only 6 months of treatment. Late relapse is negligible after SVR. This viral cure reverses hepatic fibrosis, reduces the risk of liver failure and of hepato-cellular carcinoma. Combination therapy requires a supportive setting to minimize the impact of side-effects and maximize therapeutic effectiveness. Overall management of HCV-infected persons must also embrace measures to improve quality of life by preventing or dealing with psychosocial issues and advocating lifestyle changes to counter comorbidity from alcohol, central obesity and insulin resistance. These latter factors favour fibrotic disease progression, complications of cirrhosis (such as hepatocellular carcinoma) and development of type 2 diabetes mellitus, as well as eroding the chances of SVR with antiviral therapy.

Evaluation of amantadine in chronic hepatitis C: a meta-analysis

BACKGROUND/AIMS

The benefit of amantadine combination therapy, either with interferon (IFN) alone (double therapy) or with ribavirin and IFN (triple therapy) is unknown.

METHODS

We analyzed the effect of amantadine on the end-of-treatment virological response and the sustained response using meta-analysis of 31 randomized controlled trials.

RESULTS

Overall analysis revealed a significant effect of amantadine. Triple therapy was the best regimen for improving the sustained response (mean difference: 8.4%, 95% CI: 2.4-13.8%, P=0.002). In subgroup analysis, amantadine did not have a significant effect upon naive patients or relapsers. In non-responders, combination therapy with amantadine was associated with a significant effect on the sustained response (mean difference: 8.3%, 95% CI: 1.9-14.6%, P=0.01). In sensitivity analysis, double therapy did not improve virological responses. Conversely, triple therapy tended to improve the end-of-treatment virological response and was associated with a significant effect upon the sustained response (mean difference: 12.7%, 95% CI: 3.8-21.6%, P=0.005).

CONCLUSIONS

Combination therapy with amantadine is of no effect upon naive patients or relapsers. In non-responders, triple therapy with amantadine improved the sustained response. New randomized controlled trials are required to confirm this meta-analysis.

Enhanced nucleic acid binding to ATP-bound hepatitis C virus NS3 helicase at low pH activates RNA unwinding

The molecular basis of the low-pH activation of the helicase encoded by the hepatitis C virus (HCV) was examined using either a full-length NS3 protein/NS4A cofactor complex or truncated NS3 proteins lacking the protease domain, which were isolated from three different viral genotypes. All proteins unwound RNA and DNA best at pH 6.5, which demonstrate that conserved NS3 helicase domain amino acids are responsible for low-pH enzyme activation. DNA unwinding was less sensitive to pH changes than RNA unwinding. Both the turnover rate of ATP hydrolysis and the K(m) of ATP were similar between pH 6 and 10, but the concentration of nucleic acid needed to stimulate ATP hydrolysis decreased almost 50-fold when the pH was lowered from 7.5 to 6.5. In direct-binding experiments, HCV helicase bound DNA weakly at high pH only in the presence of the non-hydrolyzable ATP analog, ADP(BeF3). These data suggest that a low-pH environment might be required for efficient HCV RNA translation or replication, and support a model in which an acidic residue rotates toward the RNA backbone upon ATP binding repelling nucleic acid from the binding cleft.