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

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.

Pegylated interferon and ribavirin in the retreatment of chronic hepatitis C in Korea

Background/Aims

Pegylated interferon (peginterferon) and ribavirin is the current standard therapy for chronic hepatitis C. The aims of this study were to evaluate the efficacy of peginterferon and ribavirin and to identify predictors of a sustained virological response (SVR) to the retreatment of chronic hepatitis C in Korea.

Methods

The clinical records of 91 patients with chronic hepatitis C who were retreated with peginterferon and ribavirin were retrospectively analyzed. None of the patients had previously attained a SVR, and the patients were categorized according to their previous responses (nonresponder, relapser, or inadequate treatment) to conventional interferon/ribavirin.

Results

The overall SVR rate was 54.9%. Independent predictors of a SVR were genotypes 2 and 3, relapse, an adherence to peginterferon of over 80%, and an early virological response (EVR). For genotype 1 patients, an adherence to peginterferon of over 80% was an independent predictor of a SVR.

Conclusions

Peginterferon and ribavirin therapy is effective for the retreatment of Korean chronic hepatitis C patients who have failed interferon/ribavirin, especially in patients with genotypes 2 and 3, relapse, an adherence to peginterferon over 80%, and an EVR. For genotype 1 patients, retreatment was effective in patients with an adherence to peginterferon over 80%.

Meta-analysis: mortality and serious adverse events of peginterferon plus ribavirin therapy for chronic hepatitis C

BACKGROUND

Pegylated interferon (PEG-IFN) plus ribavirin (RBV) therapy is the current standard of care for patients with chronic hepatitis C. Determining precisely the risk of serious adverse events (SAEs) and mortality from a single study is rather difficult because of the infrequency of such events. The aim of this systematic review was to assess the rates of SAEs and the mortality of PEG-IFN/RBV therapy in a pooled large sample, and to assess the relationship between SAEs and mortality rates and therapeutic characteristics.

METHODS

A literature search was conducted using MEDLINE, EMBASE, and the Cochrane Library to identify randomized controlled trials evaluating the efficacy and safety of PEG-IFN/RBV therapy. We calculated the crude mortality and SAE rates with 95% confidence intervals (CIs).

RESULTS

Eighty studies with 153 treatment arms that included 27569 patients were enrolled (14401 patients treated with Peg-IFN alpha-2a/RBV and 13168 with Peg-IFN alpha-2b/RBV). All-cause and treatment-related deaths were observed in 50 (0.18%; 95% confidence interval [CI] 0.13-0.24%) and sixteen (0.058%; 95% CI 0.033-0.094%) patients, respectively. The crude SAE rate was 7.08% (95% CI 6.75-7.41%). Subgroup analysis revealed higher SAE rates in patients receiving PEG-IFN alpha-2a than in those with PEG-IFN alpha-2b (7.45 vs. 6.74%), and higher SAE rates with higher doses than with the lower doses in PEG-IFN-2a and 2b (11.94 vs. 6.99%, 7.10 vs. 5.05%, respectively), and with extended duration (> 48 weeks) than with standard duration (48 weeks) (15.5 vs. 6.67%) in PEG-IFN alpha-2a.

CONCLUSION

The mortality rate during PEG-IFN/RBV therapy was acceptably low, but the rate of SAEs was not negligible in a treatment for a benign disease, and the rate was affected by treatment regimens.

Differences in clinical outcomes among hepatitis C genotype 1-infected patients treated with peginterferon alpha-2a or peginterferon alpha-2b plus ribavirin: a meta-analysis

Background

With the development of new direct acting antiviral (DAA) therapy for hepatitis C, the backbone peginterferon alpha used may be of importance in maximizing treatment outcomes. To this end, the rates of sustained virologic response (SVR), relapse, and treatment discontinuation among hepatitis C genotype 1-infected patients given peginterferon alpha-2a plus ribavirin or peginterferon alpha-2b plus ribavirin were determined using a meta-analysis.

Methods

Randomized trials examining peginterferon alpha-2a or peginterferon alpha-2b co-administered with ribavirin for 48 weeks were included. Data were extracted on SVR, relapse, and treatment discontinuations for treatment-naïve and treatment-experienced patients. Pooled proportions using fixed and random effects meta-analysis were calculated.

Results

Twenty-six trials provided data on patients treated with peginterferon alpha-2a plus ribavirin, and 19 trials provided data on patients treated with peginterferon alpha-2b plus ribavirin. Five trials were direct head-to-head evaluations. In the subset of trials that included head-to-head evaluations, no significant differences were observed between the two treatments for treatment-naïve (relative risk [RR]: 1.07, 95% confidence intervals [CI]: 0.97–1.18) and treatment-experienced patients (RR: 1.27, 95% CI: 0.58–2.77). Using only active trial arms, a larger proportion of the treatment- naïve patients who were provided peginterferon alpha-2a plus ribavirin achieved a SVR (47%), which is greater than that of treatment-naïve patients who were provided peginterferon alpha- 2b plus ribavirin (40% SVR achievement); however, a larger proportion of treatment- experienced patients who were provided peginterferon alpha-2b plus ribavirin achieved a SVR (16%) when compared with treatment-experienced patients given peginterferon alpha-2a plus ribavirin (12% SVR achievement). A larger proportion of relapses occurred among both treatment-naïve and treatment-experienced patients given peginterferon alpha-2a plus ribavirin, when compared with treatment-naïve and treatment-experienced patients taking peginterferon alpha-2b plus ribavirin. The proportion of patients discontinuing treatment was greater among treatment-naïve patients taking peginterferon alpha-2a plus ribavirin, but smaller among treatment-experienced patients.

Conclusion

There are small differences in treatment outcomes for different types of peginterferon- alpha. Patient status and complexity of administration may differentiate clinical outcomes.

Meta-analysis: re-treatment of genotype I hepatitis C nonresponders and relapsers after failing interferon and ribavirin combination therapy

BACKGROUND

The efficacy of re-treating genotype I hepatitis C virus (HCV) patients who failed combination therapy with interferon/pegylated interferon (PEG-IFN) and ribavirin remains unclear.

AIMS

To quantify sustained virological response (SVR) rates with different re-treatment regimens through meta-analysis of randomized controlled trials (RCTs).

METHODS

Randomized controlled trials of genotype I HCV treatment failure patients that compared currently available re-treatment regimens were selected. Two investigators independently extracted data on patient population, methods and results. The pooled relative risk of SVR for treatment regimens was computed using a random effects model.

RESULTS

Eighteen RCTs were included. In nonresponders to standard interferon/ribavirin, re-treatment with high-dose PEG-IFN combination therapy improved SVR compared with standard PEG-IFN combination therapy (RR=1.49; 95% CI: 1.09-2.04), but SVR rates did not exceed 18% in most studies. In relapsers to standard interferon/ribavirin, re-treatment with high-dose PEG-IFN or prolonged CIFN improved SVR (RR=1.57; 95% CI: 1.16-2.14) and achieved SVR rates of 43-69%.

CONCLUSIONS

In genotype I HCV treatment failure patients who received combination therapy, re-treatment with high-dose PEG-IFN combination therapy is superior to re-treatment with standard combination therapy, although SVR rates are variable for nonresponders (≤18%) and relapsers (43-69%). Re-treatment may be appropriate for select patients, especially relapsers and individuals with bridging fibrosis or compensated cirrhosis.

Retrospective, observational, multicentre study on an Italian population affected by chronic hepatitis C who failed to clear HCV-RNA after the combined therapy (PEG-IFN and ribavirin): NADIR study

There is a lack of information on the characteristics of patients with chronic hepatitis C virus infection (HCV) who fail to respond to antiviral treatment. We studied HCV-positive subjects with chronic liver diseases treated with pegylated-interferon (PEG-IFN) and ribavirin (RBV) who failed to clear HCV in routine clinical practice. A total of 2150 consecutive adult patients treated with PEG-IFN plus RBV therapy in 46 Italian centres between 1 July 2004, and 30 June 2005, were studied. Of the 2150 patients, 923 (42.9%) (M/F 585/335, mean age 54.8 years) failed to achieve a serum HCV-RNA clearance. Of these 923 patients, 429 (46.5%) were nonresponders, 298 (32.3%) relapsers, 168 (18.2%) drop-outs for noncompliance or adverse events and 28 (3.0%) were lost during follow-up. Overall, 642 (70.6%) patients received adequate therapy (defined as more than 80% of the drug doses for >80% of the time). Genotypes 1-4 were observed in 76.9% of cases; genotypes 2-3 in 21.2% and mixed in 1.9%, respectively. Multiple logistic regression analysis identified genotypes 1 and 4 as the sole independent predictors of the likelihood of nonresponse to therapy compared with relapse (OR: 4.38; 95% CI = 2.28-8.4). Age older than 65 years was the sole independent factor associated with no adherence to therapy (OR: 2.22; 95% CI = 1.36-3.62). Patients who fail to respond to treatment are a nonhomogeneous population with different features, and the sole factor that discriminates nonresponse from relapse is the distribution of genotypes 1-4. Co-morbidities are unable to determine the type of treatment failure and inadequate adherence to therapy mostly affects patients older than 65 years of age.

Practice guidelines for the treatment of hepatitis C: recommendations from an AISF/SIMIT/SIMAST Expert Opinion Meeting

It is increasingly clear that a tailored therapeutic approach to patients with hepatitis C virus infection is needed. Success rates in difficult to treat and low-responsive hepatitis C virus patients are not completely satisfactory, and there is the need to optimise treatment duration and intensity in patients with the highest likelihood of response. In addition, the management of special patient categories originally excluded from phase III registration trials needs to be critically re-evaluated. This article reports the recommendations for the treatment of hepatitis C virus infection on an individual basis, drafted by experts of three scientific societies.

Retreatment with pegylated interferon plus ribavirin of chronic hepatitis C non-responders to interferon plus ribavirin: a meta-analysis

BACKGROUND/AIMS

Efficacy of retreatment with pegylated interferon (PEG-IFN) plus ribavirin of non-responders to standard or pegylated IFN plus ribavirin has been assessed in various studies, but sustained virologic response (SVR) rates are variable and factors influencing efficacy and tolerability still remain incompletely defined. We aimed to focus on SVR rates and to identify factors influencing them in this meta-analysis.

METHODS

MEDLINE as well as a manual search were used. Studies were included if they were controlled or uncontrolled trials, if they had been published as full-length papers and if they included non-responders to standard or pegylated IFN and ribavirin therapy. Fourteen trials were included in the meta-analysis. Data on study populations, interventions, and outcomes were extracted from trials using a random-effects model. Primary outcome was the SVR rate.

RESULTS

The pooled estimate of SVR rate was 16.3% (95% Confidence Interval - 95% CI, 8.3-29.6%). There was a significant heterogeneity among studies (p<0.0001). Heterogeneity was less apparent in studies that included fewer patients with cirrhosis or overweight. By meta-regression, higher SVR rate was observed in trials with a lower prevalence of subjects with genotype 1 infection and with fewer overweight patients. The use of a 24-week retreatment stopping rule did not affect SVR rate.

CONCLUSIONS

The overall modest efficacy argues against an indiscriminate retreatment with PEG-IFN and ribavirin of all non-responders. Restricting retreatment to non-overweight patients or to those with genotype 2 or 3 infection, using a 24-week retreatment stopping rule, would optimize the potential benefit with a scarce likelihood of missing a curative response.

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.

Distribution and dynamics of adamantanes in a lipid bilayer

The adamantanes are a class of compounds that have found use in the treatment of influenza A and Parkinson's disease, among others. The mode of action for influenza A is based on the adamantanes' interaction with the transmembrane M2 channel, whereas the treatment of Parkinson's disease is thought to relate to a channel block of N-methyl-D-aspartate receptors. An understanding of how these compounds interact with the lipid bilayer is thus of great interest. We used molecular-dynamics simulations to calculate the potential of mean force of adamantanes in a lipid bilayer. Our results demonstrate a preference for the interfacial region of the lipid bilayer for both protonated and deprotonated species, with the protonated species proving significantly more favorable. However, the protonated species have a large free-energy barrier in the center of the membrane. In contrast, there is no barrier (compared with aqueous solution) at the center of the bilayer for deprotonated species, suggesting that the permeant species is indeed the neutral form, as commonly assumed. We discuss the results with respect to proposed mechanisms of action and implications for drug-delivery in general.

Controversies in and challenges to our understanding of hepatitis C

Discovered in 1989, the hepatitis C virus (HCV) continues to cause significant morbidity and mortality world-wide despite a huge research commitment to defining and understanding the virus and the disease it causes. This paper discusses a number of areas where progress in the management of the HCV have not kept pace with the scientific understanding of the HCV. It is suggested that in the fields of HCV prevention and providing access to treatment, practice falls short of what could be achieved. The role of alcohol in the pathogenesis of HCV liver injury is discussed. Discrimination against those with HCV infection and particularly those in prison settings fails to match good clinical practice. The complicated processes of sharing information between specialty groups is also discussed in an attempt to optimise knowledge dissemination in this field.