A randomized trial of high-dose interferon alpha-2b, with or without ribavirin, in chronic hepatitis C patients who have not responded to standard dose interferon

A statistical method for removing unbalanced trials with multiple covariates in meta-analysis

In meta-analysis literature, there are several checklists describing the procedures necessary to evaluate studies from a qualitative point of view, whereas preliminary quantitative and statistical investigations on the "combinability" of trials have been neglected. Covariate balance is an important prerequisite to conduct meta-analysis. We propose a method to identify unbalanced trials with respect to a set of covariates, in presence of covariate imbalance, namely when the randomized controlled trials generate a meta-sample that cannot satisfy the requisite of randomization/combinability in meta-analysis. The method is able to identify the unbalanced trials, through four stages aimed at achieving combinability. The studies responsible for the imbalance are identified, and then they can be eliminated. The proposed procedure is simple and relies on the combined Anderson-Darling test applied to the Empirical Cumulative Distribution Functions of both experimental and control meta-arms. To illustrate the method in practice, two datasets from well-known meta-analyses in the literature are used.

Ribavirin plus interferon versus interferon for chronic hepatitis C

BACKGROUND

Hepatitis C is a major cause of liver-related morbidity and mortality. Standard therapy is ribavirin plus pegylated interferon to achieve undetectable level of virus in the blood, but the effect on clinical outcomes is controversial.

OBJECTIVES

To assess the beneficial and harmful effects of ribavirin and interferon combination therapy versus interferon monotherapy for chronic hepatitis C.

SEARCH STRATEGY

We identified trials through electronic databases, manual searches of bibliographies and journals, approaching authors of trials, and pharmaceutical companies until March 2009.

SELECTION CRITERIA

We included randomised trials, irrespective of blinding, language, or publication status, comparing ribavirin plus interferon versus interferon for treatment of chronic hepatitis C.

DATA COLLECTION AND ANALYSIS

The primary outcome measures were serum sustained loss of hepatitis C virus, liver-related morbidity plus all-cause mortality, and adverse events. We performed subgroup analyses of patients who were naive, relapsers, or non-responders to previous antiviral treatment. All outcomes were analysed with the random-effects model. We used Peto odds ratios (OR) with 95% confidence intervals (CI) for analysis of morbidity plus mortality. The remaining outcomes were presented as relative risks (RR). We used trial sequential analyses to examine the robustness of our findings.

MAIN RESULTS

We included 83 randomised trials with 12,707 patients. Most trials had unclear or high risk of bias. We did not find any significant influence of bias on our results but cannot exclude outcome measure reporting bias as many trials did not report on the primary outcomes of this review. Compared with interferon, ribavirin plus interferon had a significant beneficial effect on sustained virological response in subgroups of naive patients (RR 0.72, 95% confidence interval (CI) 0.68 to 0.75), relapsers (RR 0.62, 95% CI 0.54 to 0.70), non-responders (RR 0.89, 95% CI 0.84 to 0.93), and in all patients (RR 0.75, 95% CI 0.71 to 0.79). Combination therapy significantly reduced morbidity plus mortality in all patients (Peto OR, 0.43, 95% CI 0.23 to 0.79), but not in naive, relapsers, or non-responders individually. Combination therapy significantly increased the risk of haematological, dermatological, gastrointestinal, infectious, and miscellaneous (cough, dyspnoea, fatigue) adverse reactions. Accordingly, combination therapy significantly increased the risk of treatment discontinuation and dose reductions. Trial sequential analyses confirmed our findings regarding virological effects, but not regarding liver-related morbidity and all-cause mortality.

AUTHORS' CONCLUSIONS

Compared with interferon alone, ribavirin plus interferon is more effective in clearing hepatitis C virus from the blood. Combination therapy may reduce liver-related morbidity and all-cause mortality, but we need more evidence. The number needed to treat to obtain a beneficial effect is considerable considering the increased risk of several severe adverse reactions and costs.

Ribavirin monotherapy for chronic hepatitis C

BACKGROUND

Hepatitis C is a major cause of liver-related morbidity and mortality. A high proportion of patients never experience symptoms. Peginterferon plus ribavirin is the recommended treatment for chronic hepatitis C. However, ribavirin monotherapy may be considered for some patients.

OBJECTIVES

To assess the beneficial and harmful effects of ribavirin monotherapy for patients with chronic hepatitis C.

SEARCH STRATEGY

We identified trials through electronic databases, manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies until March 2009.

SELECTION CRITERIA

We included all randomised trials irrespective of blinding, language, or publication status comparing ribavirin versus no intervention, placebo, or interferon for chronic hepatitis C.

DATA COLLECTION AND ANALYSIS

The primary outcome measures were serum sustained virological response (loss of hepatitis C virus RNA at least six months after treatment), liver-related morbidity plus all-cause mortality, and adverse events. Secondary outcome measures were end of treatment virological response, biochemical response (transaminase activity), and histological response. Randomisation methods, blinding, data handling, and funding were extracted as measures of bias control. Random-effects and fixed-effect meta-analyses were performed for all outcomes. We only present the results of the fixed-effect model if both models provide the same result regarding statistical significance. We present data as risk difference (RD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 14 randomised trials with 657 patients. The majority of trials had unclear control of bias. Compared with placebo or no intervention, ribavirin had no significant effect on the sustained virological response (RD 0%, 95% CI -2% to 3%, five trials) or end of treatment virological response (RD 0% 95% CI -3% to 3%, ten trials). Ribavirin had no significant effect on liver-related morbidity plus mortality (RD 0%, 95% CI -2% to 3%, 11 trials). Ribavirin significantly increased the risk of adverse reactions, including anaemia. Ribavirin significantly improved end of treatment biochemical and histological response but not the sustained biochemical response. Ribavirin was significantly inferior to interferon regarding virological and biochemical responses (five trials).

AUTHORS' CONCLUSIONS

Ribavirin seems without beneficial effects on serum virological response and liver-related morbidity or mortality, and significantly increased the risk of adverse reactions. Ribavirin monotherapy seems significantly inferior to interferon monotherapy. The total number of included patients is small, and more trials are perhaps needed. The use of ribavirin monotherapy for chronic hepatitis C cannot be recommended outside randomised trials.

Ribavirin monotherapy for chronic hepatitis C

BACKGROUND

Hepatitis C is a major cause of liver-related morbidity and mortality. The disease progresses without symptoms for several decades. Ribavirin monotherapy may represent a treatment for some patients.

OBJECTIVES

To assess the beneficial and harmful effect of ribavirin monotherapy for patients with chronic hepatitis C.

SEARCH STRATEGY

We identified trials through electronic databases, manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies until May 2005.

SELECTION CRITERIA

We included all randomised trials irrespective of blinding, language, or publication status comparing ribavirin versus no intervention, placebo, or interferon for chronic hepatitis C.

DATA COLLECTION AND ANALYSIS

The primary outcome measures were the six months sustained loss of hepatitis C virus RNA in blood after end of treatment and liver-related morbidity plus all-cause mortality. Secondary outcome measures were end of treatment virological response, biochemical response, histological response, and adverse events. Random- and fixed-effects meta-analyses with 95% confidence intervals (CI) were performed for all outcomes. We used Peto odds ratios (OR) for analysis of morbidity plus mortality and relative risks (RR) for the remaining outcomes.

MAIN RESULTS

We identified 13 randomised trials including 594 patients with chronic hepatitis C. Most trials had low methodological quality. Compared with placebo/no intervention, ribavirin had no significant effect on sustained (RR 1.01, 95% CI 0.96 to 1.07, five trials) or end of treatment virological response (RR 1.00, 95% CI 0.94 to 1.07, ten trials). Ribavirin had no significant effect on liver-related morbidity plus mortality (Peto OR 1.96, 95% CI 0.20 to 19.0, eleven trials). Ribavirin significantly improved end of treatment biochemical and histological response but not sustained biochemical response. Further, ribavirin significantly increased the risk of anaemia. Ribavirin was significantly inferior to interferon regarding virological and biochemical response (four trials).

AUTHORS' CONCLUSIONS

We found that ribavirin versus placebo/no intervention had no significant beneficial effect on virological response and liver morbidity, but may improve biochemical and histological response transiently. Ribavirin increased the risk of anaemia. Therefore, we cannot recommend ribavirin monotherapy for patients with chronic hepatitis C outside randomised trials.

Ribavirin plus interferon versus interferon for chronic hepatitis C

BACKGROUND

Hepatitis C is a major cause of liver-related morbidity and mortality. The disease progresses without symptoms for several decades and most patients are diagnosed based on the presence of hepatitis C virus ribonucleic acid and elevated transaminases.

OBJECTIVES

To assess the beneficial and harmful effects of ribavirin and interferon combination therapy versus interferon monotherapy for chronic hepatitis C.

SEARCH STRATEGY

We identified trials through electronic databases, manual searches of bibliographies and journals, approaching authors of trials and pharmaceutical companies, until May 2004.

SELECTION CRITERIA

We included randomised trials, irrespective of blinding, language, or publication status, comparing ribavirin plus interferon versus interferon alone for treatment of chronic hepatitis C.

DATA COLLECTION AND ANALYSIS

The primary outcome measures were the sustained loss of hepatitis C virus and liver-related morbidity plus all-cause mortality. We separately analysed patients who were naive, relapsers, or non-responders to previous antiviral treatment. Random-effects and fixed-effect model meta-analyses were performed for all outcomes. We used Peto odds ratios (OR) with 95% confidence intervals (CI) for analysis of morbidity plus mortality. The remaining outcomes were presented as relative risks (RR).

MAIN RESULTS

We included 72 randomised trials with 9991 patients. Most trials had low methodological quality but we did not find any significant influence of quality on our results. Compared with interferon, combination therapy had a significant beneficial effect on sustained virological response (RR 0.73, 95% CI 0.71 to 0.75) and in subgroups of naive patients (RR 0.72, 95% CI 0.68 to 0.76), relapsers (RR 0.63, 95% CI 0.54 to 0.73), and non-responders (RR 0.89, 95% CI 0.84 to 0.94) individually. Combination therapy significantly reduced morbidity plus mortality (Peto OR 0.46, 95% CI 0.22 to 0.96), but not in naive, relapsers, or non-responders individually. Combination therapy also had a significant beneficial effect on the histological response. Combination therapy significantly increased the risk of anaemia (RR 10.48, 95% CI 5.34 to 20.55), which occurred in 22% of patients on combination therapy. Combination therapy also significantly increased the risk of dermatological, gastrointestinal, infectious, and miscellaneous (cough, dyspnea, fatigue) adverse events. Accordingly, combination therapy significantly increased the risk of treatment discontinuation (RR 1.19, 95% CI 1.01 to 1.39).

AUTHORS' CONCLUSIONS

Compared with interferon alone, ribavirin plus interferon is more effective in clearing hepatitis C virus and improving liver histology. This may lead to reduced morbidity and mortality. However, combination therapy significantly increased the risk of several adverse events.

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Interferon-alpha2b induction treatment with or without ribavirin in chronic hepatitis C: a multicenter, randomized, controlled trial

We aimed to compare the efficacy of interferon-alpha2b (IFN) induction treatment in combination with ribavirin to IFN induction alone in chronic hepatitis C. In total, 125 patients (66 male, 59 female, mean age: 48 +/- 9, range: 21-70) were enrolled and randomized into two arms: In the first, patients received 5 MU/day of IFN for 4 weeks followed by 3 MU/day for the next 4 weeks. Treatment was continued with 3 MU three times a week IFN for an additional 40 weeks. Ribavirin was administered 1000-1200 mg/day according to the body weight for the entire 48-week period. In the second arm, patients received placebo in addition to IFN. Fifty-nine patients were placed in the ribavirin arm and 66 in placebo arm. All patients were genotype 1. At week 48, 24/66 (36%) from the placebo and 31/59 (52%) from the ribavirin group responded (P > 0.05). However, during the 24-week untreated follow-up period, 13/24 (54%) from the placebo, and 8/31 (26%) from the ribavirin group relapsed (P = 0.002.), resulting in a sustained virologic response (SVR) rate of 17% in the placebo and 39% in the ribavirin group (P = 0.005.) In conclusion, IFN induction treatment in combination with ribavirin is superior to IFN induction treatment alone in genotype 1 patients, and the SVR rate of 39% is encouraging.

Induction interferon and ribavirin for re-treatment of chronic hepatitis C patients unresponsive to interferon alone

BACKGROUND

The optimal treatment for hepatitis C patients unresponsive to interferon is unclear. High-dose induction interferon may enhance early viral clearance, whilst ribavirin reduces relapse; in combination, they may improve sustained virological response rates.

AIM

To compare the efficacy and safety of re-treatment with interferon induction, with or without ribavirin, in interferon non-responders.

METHODS

We randomized 218 biochemical interferon non-responders to 10 MU interferon alpha 2b daily for 4 weeks, followed by 5 MU thrice weekly for 48 weeks plus ribavirin (II + R), or to the same interferon regimen plus placebo (II + P). All patients were viraemic at entry.

RESULTS

The sustained virological response in the II + R group was 39%[95% confidence interval (CI), 30-48%], compared with 16% (95% CI, 9-23%) in the II + P group (P < 0.002). The study drug was discontinued for intolerable symptoms during induction in 9% of the II + R group and in 5% of the II + P group. By logistic regression, a sustained virological response was more likely following II + R treatment (odds ratio, 4.4; 95% CI, 2.1-9.7) and less likely in patients with genotype 1 or 4 (odds ratio, 0.16; 95% CI, 0.07-0.36).

CONCLUSION

High-dose induction interferon plus ribavirin is well tolerated and effective for patients unresponsive to interferon alone.

Treatment of chronic hepatitis C in nonresponders to previous therapy

About 55% to 60% of treatment-naïve patients fail to achieve a sustained virologic response after therapy with standard interferon and ribavirin. The use of polyethylene glycol-enhanced interferon (PEG-IFN) plus ribavirin for retreatment of this challenging group is currently being evaluated by several investigators. Although no sustained virologic response rates have been reported yet from these trials, reported on-treatment response rates for previous nonresponders range from 25% to 30%, and an early estimate of the sustained virologic response rate is about 11%. Outcomes for treatment of relapsers and interferon monotherapy nonresponders have been significantly better than those for combination nonresponders. On-treatment responses of 40% to 43% in previous combination therapy nonresponders are now being seen with the addition of amantadine (triple therapy), and sustained response rates with this regimen are awaited. Large trials are underway to evaluate the role of maintenance therapy for virologic nonresponders with advanced liver disease.