A randomized controlled trial of amantadine plus interferon-alpha2a vs. interferon-alpha2a alone in naive patients with chronic hepatitis C randomized according to the early virological response to interferon-alpha2a monotherapy

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.

A randomized controlled trial of double versus triple therapy with amantadine for genotype 1 chronic hepatitis C in Latino patients

BACKGROUND

With only a third of Latinos achieving sustained virologic response (SVR), there is a need for enhanced HCV treatment. Amantadine has been proposed to improve response rates in addition to standard therapy with peginterferon alpha and ribavirin. Our objective is to evaluate whether triple therapy with amantadine improves SVR rates in this special population.

METHOD

Treatment-naïve Latino subjects with HCV genotype 1 infection were randomized to receive peginterferon alpha-2a plus weight-based ribavirin for 48 weeks (double therapy) or the same regimen plus amantadine 200 mg daily (triple therapy). The primary endpoint was SVR. Predictors of liver fibrosis using APRI and Forns indices were also evaluated.

RESULTS

We enrolled 124 patients with chronic hepatitis C genotype 1. Sixty-three received conventional therapy and 61 patients had triple therapy with amantadine. SVR at week 72 was achieved in 25 patients (39.7%) vs. 26 patients (42.6%) in the double and triple regimen, respectively (p=0.561). After multivariate analysis, advanced fibrosis, obesity, and low pretreatment ALT levels were associated with non-response in both groups (p=0.0234, p=0.0012, p=0.0249, respectively). APRI values delimited an area under the ROC curve (AUROC) of 0.724 and Forns index with AUROC of 0.733. There was no difference between both indices in predicting significant fibrosis (Knodell index: F3-F4).

CONCLUSION

Our study demonstrates that the addition of amantadine to standard treatment of chronic HCV does not improve SVR rates in Latino patients with genotype 1. Further research to improve response rates in this special population is needed.

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.

Another ten stories in antiviral drug discovery (part C): "Old" and "new" antivirals, strategies, and perspectives

The ten stories told here deal with (i) ribavirin as an inhibitor of IMP dehydrogenase and (ii) ribavirin, in combination with pegylated interferon, as the present "standard of care" for hepatitis C; (iii) S-adenosylhomocysteine hydrolase inhibitors as antiviral agents; (iv) new adamantadine derivatives for the treatment of influenza A virus infections; (v) 5-substituted 2'-deoxyuridines (i.e. IDU, TFT) for the treatment of herpes simplex virus (HSV) infections; (vi) acyclic guanosine analogues (e.g. acyclovir) for the treatment of HSV infections; (vii) OMP decarboxylase inhibitors (i.e. pyrazofurin) and CTP synthetase inhibitors (i.e. cyclopentenylcytosine) as possible antiviral agents; (viii) the future of cidofovir (and alkoxyalkyl esters thereof) and ST-246 as potential antipoxvirus agents; (ix) the two decade journey from tivirapine to rilpivirine in the ultimate therapy of HIV infections; and (x) the extension of the therapeutic application of tenofovir disoproxil fumarate (Viread) to the treatment of hepatitis B virus infection, in addition to HIV infection.

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.

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.

Treatment of chronic hepatitis C in non-responsive patients with pegylated interferon associated with ribavirin and thalidomide: report of six cases of total remission

Hepatitis C virus (HCV) infection is an important public health issue worldwide. It is estimated that over 170 million people are infected with the virus. The present study reports six cases in which patients did not respond to combination therapy with pegylated interferon and ribavirin. However, after the addition of thalidomide to the therapy, the patients presented negative RNA PCR. The use of thalidomide combined with pegylated interferon and ribavirin for the treatment of hepatitis C is described here for the first time in the related literature.

Effect of interferon and ribavirin combined with amantadine in interferon and ribavirin non-responder patients with chronic hepatitis C (genotype 1)

AIM: To evaluate the efficacy of amantadine plus interferon-alpha and ribavirin in non-responder patients with chronic hepatitis C.

METHODS: Twenty-six non-responder patients received the regimen of IFN-α-2a at a dose of 6 million units three times a week, 1000-1200 mg of ribavirin daily, and 200 mg of amantadine daily in divided doses over 48 wk. After the end of treatment, at the 72^nd wk, a sustained viral response rate was determined.

RESULTS: An early (after 12 wk of therapy) response was seen in 34.6% (9/26) of patients. Response rate at the 24^th wk was 42.3% (11/26). End of treatment response (ETR) was 53.8% (14/26). Sustained viral response (SVR) was 42.3% (11/26). There was a statistically significant difference between 0 and 12 wk (P = 0.04), 0 and 24 wk (P = 0.01), 0 and 48 wk (P = 0.00), and 0 and 72 wk (P = 0.001). No patient had severe adverse effects during the treatment.

CONCLUSION: Combination regimen of interferon-α, ribavirin and amantadine can enhance sustained viral response on IFN-α and ribavirin non-responder patients with HCV. Triple therapy with amantadine should be evaluated in further studies.

Advances in hepatitis B and C

PURPOSE OF REVIEW

Hepatitis B and C infections are prevalent around the world and a major health burden due to the associated complications of hepatic fibrosis, cirrhosis and hepatocellular carcinoma which occur in the context of chronic infection. Significant advances are being made in assessing and treating infected patients and recent studies are now targeting patients who have failed to respond to previous treatments or who have associated co-morbidities. The purpose of this article to review the recent literature on the subject of hepatitis B and C infections with particular focus on new treatment options, new approaches in patients who have previously failed therapy and in those who have co-morbidity.

RECENT FINDINGS

A large number of studies have been carried out investigating the roles of varying doses, targeting treatment in particular groups and new treatment options in patients infected with hepatitis B and C. Several key findings such as the value of prolonging treatment in patients with genotype 1 hepatitis C infection, the use of pegylated interferon in chronic hepatitis B infection and the emergence of new treatments such as adefovir for resistant hepatitis B infection, as well as treatment of patients co-infected with hepatitis C and human immunodeficiency virus, have dominated the recent literature. Patients in particular groups such as those who have had liver transplantation or who are immunosuppressed have also received added attention.

SUMMARY

Hepatitis B and C infections are the focus of much current attention with particular regard to new and emerging treatment options which are becoming increasingly focused on varying patient groups.

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.