Long-term histologic and viral changes in patients with chronic hepatitis C who responded to alpha interferon

Fibrosis in chronic viral hepatitis

In the last years, several studies have been performed with the aim to evaluate the real impact of antiviral treatments on fibrosis progression in patients with chronic viral hepatitis. The main goal of therapy in patients with chronic hepatitis B is viral suppression. This outcome leads to an important improvement in both hepatic inflammation and fibrosis and reduces the HCC occurrence. An histological improvement has been largely demonstrated in patient treated with oral nucleoside and nucleotide analogs achieving the rate of 72% with entecavir and tenofovir. Similarly, in patients with chronic hepatitis C, sustained virologic response to interferon therapy is associated with regression of fibrosis and lower liver decompensation and HCC occurrence. In the next future further studies will assess the real impact of the new directly anti-viral agents on liver necroinflammation and fibrosis in chronic hepatitis C.

A decade of trials of interferon-alpha for chronic hepatitis C. A meta-regression analysis

The most relevant randomized controlled trials of interferon-alpha (IFN) for naive patients with chronic hepatitis C (CHC) published in a decade, just before appearance of pegylated IFN trials in 2000, were included in this paper. Its purpose is to review the relationship between sustained biochemical response in active versus control group versus usual clinical variables as IFN regimens, cirrhosis, genotype and versus less frequently addressed variables as funding, methodological quality or location of principal author. Meta-analysis estimates of global treatment effect varied according to trial design: group 1=IFN versus placebo/no treatment, 32 RCTs, 2499 pts, OR 9.5 (6.3-14.2); group 2a=comparison of IFN schedules, 43 RCTs, 7454 pts, OR 1.6 (1.4-1.9); group 2b=IFN+other drugs versus standard IFN, 30 RCTs, 4737 pts, OR 2.0 (1.6-2.6). Fixed effects (arm-level) meta-regression on the complete data set (171 arms, 10,580 pts) revealed that sustained response was most likely in experimental arms of IFN+ribavirin or other drugs (OR 2.4), arms using yearly schedule (OR 2.0), trial principal author from Asia (OR 1.7), trial sample size >200 (OR 1.4) and arms enrolling less than 50% of cirrhotics (OR 1.3). Moreover, focus was on some significant interactions too, as the effect of trial's quality interacting to the recorded funding (more benefit if no-profit, less if for-profit) and the effect of trial funding interacting to the location of first author (more benefit if from Asia). Three main effects (experimental arm, cirrhosis, funding) and one interaction (funding*location of principal author) explained 31% of between study variability in a random-effect meta-regression. In a subgroup analysis on a data set including available information on HCV genotype (93 arms, around 7000 pts), meta-regression revealed that genotype 1 or 4 less than 50% per arm and specialistic journal were significant predictors of either biochemical (transaminases) or virological (HCV-RNA) sustained response, in a model including the same main effects identified in the complete data set analysis. Finally, although mostly captured by different IFN regimens along time, heterogeneity of effect in a large set of (not-pegylated) IFN trials was also explained by HCV genotype and variables of quality and reporting, such as trial's principal author from Asia.

Current therapy for chronic hepatitis C

Chronic hepatitis C virus infection is common in the United States with an estimated prevalence of 2.7 million persons. Fortunately, the incidence of new infections has markedly declined in recent years and the natural history of chronic hepatitis usually only results in significant progression after several decades of infection. However, the majority of chronically infected patients acquired their infections more than 20 years ago; these patients with long-standing chronic hepatitis are now presenting in increasing numbers with decompensated cirrhosis and the need for liver transplantation. Cirrhosis caused by chronic hepatitis C is now the most common indication for liver transplantation. Interferon monotherapy became clinically available 10 years ago but resulted in sustained improvement in liver disease and durable loss of detectable virus in fewer than 10% of treated patients. The recent use of the combination of interferon with the nucleoside analogue ribavirin for 6-12 months results in a sustained virological response in 30%-40% of previously untreated patients. The response to this combination therapy is also excellent in patients who had initially responded to interferon monotherapy and later relapsed. Furthermore, some recent studies suggest that a small proportion of patients who failed to respond to a prior course of interferon (primarily noncirrhotic patients with low levels of virus and genotypes other than 1) may also benefit from retreatment with this combination.

Combination treatment with interferon and ribavirin for chronic hepatitis C

Interferon was the first drug shown to be effective in patients with chronic hepatitis C, but initial treatment regimens achieved sustained loss of virus in only a small minority of patients. The combination of IFN with ribavirin now makes sustained response rates of 30% to 40% possible. This is quite a remarkable achievement for a pharmacologic treatment of a chronic viral infection. It is now reasonable to assume that early treatment and eradication of chronic hepatitis C might reduce the growing burden of hepatitis C and its complications on the healthcare system. Future researchers will strive to optimize combination treatment regimens. Longer treatment courses and intensified induction regimens using either daily dosing, high doses, or both may improve long-term response, but this remains speculative. Other forms of IFN may improve response or increase the ease of drug administration. Conjugation of biologic compounds to polyethylene glycol can result in significant prolongation of plasma half-life while maintaining the properties of the parent molecule. Some biologic properties may be altered, however, so pegylated IFN must continue to be evaluated in clinical trials. There is limited clinical data on other recombinant or natural interferons in combination with oral ribavirin, however, these may prove to be equally effective. Combinations of IFN with one or more other antiviral, anti-inflammatory, or immune modulatory agents will need to be studied. Although amantidine is not effective against hepatitis C as a single agent or in combination with IFN, the combination of IFN, ribavirin, and rimantidine has been shown to have antiviral activity superior to the IFN-ribavirin combination against influenza virus and possibly against HCV.

Enhancing the response to interferon-alpha

BACKGROUND

Though initially recognized as antiviral agents, it was soon demonstrated that certain neoplasms were particularly sensitive to interferon-alpha (IFN-alpha). Indeed, the initial success of systemic IFN-alpha treatment in AIDS-associated Kaposi's sarcoma (AIDS-KS) occurred before identification of the human immunodeficiency virus (HIV) and in the absence of any coherent view of KS pathogenesis. With a more comprehensive understanding how KS develops and which circumstances provide an increased virulence of this neoplasm in HIV-infected persons, a more subtle rationale for IFN-alpha treatment arose regarding the disorder of the endogenous IFN-system in HIV-positive individuals. Until recently IFN-alpha was the only therapy available for patients with chronic hepatitis C (CHC). However, no more than 30% of these patients show a sustained virological response. Initial therapy with a combination therapy of IFN-alpha and ribavirin turned out to be more effective than treatment with IFN-alpha alone. To ameliorate response rates in antiviral IFN-therapy a profound understanding of viral dynamics, as well as immunological conditions associated with viral persistence, seems to be essential. Within a conference of the European Society of Clinical Virology (ESCV), which took place in Hamburg from August 30 to September 2, 1998, and was entitled 'Progress in Clinical Virology IV', a satellite symposium was organized to evaluate the clinical results of special antiviral treatment options with IFN-alpha, to analyze treatment failures with this cytokine and to ameliorate future strategies of IFN-alpha therapy. It focussed on HIV-related complications as coinfection with hepatitis C virus (HCV) and AIDS-KS, respectively.

METHODS

A kinetic model of HCV infection based on principles established in studying HIV-1 infection was presented which is predictive for the outcome of IFN-alpha treatment. It involves different rates of velocity and compares the rates of acute clearance after different dosages of IFN-alpha application. Using the hypothesis to fit the changes in serum HCV RNA measured in a set of patients, it was found that 5 mIU daily dosing on average blocks 81% of HCV production/release, whereas 10 or 15 mIU blocks about 95% of HCV production/release.

RESULTS

Only recently clinical data revealed a greater benefit of combination therapy with IFN-alpha and ribavirin compared to IFN-alpha alone in patients with chronic hepatitis C. In 345 CHC patients relapsing after pretreatment with IFN-alpha monotherapy, sustained response was achieved in a 10-fold higher degree with a combination of IFN and ribavirin compared to patients retreated with IFN alone. In 1775 treatment-naive patients with CHC, response rates to the combination therapy was significantly higher in all patient groups with more than 60% of sustained virological response in patients with genotype 2 and 3, while patients with genotype 1 (poorer prognosis) benefit from extended combination treatment duration from 24 to 48 weeks (17 versus 29% of sustained virological response), respectively.

CONCLUSIONS

As viral dynamics on one side and host immune response on the other feature as two landmarks on which the manifestation of viral persistence and chronic viral infections is established, some similarities of HCV and HIV disease are striking. An unusual endogenous IFN-alpha system is associated with both infections and is a negative prognostic factor to response to treatment with IFN-alpha in CHC as well as AIDS-KS. The consequences for treatment options with IFN are a combination with ribavirin in CHC and a graduated systemic treatment schedule in AIDS-KS starting with IFN-treatment in early disease followed by chemotherapy in advanced stages of KS.

Combination therapy for chronic hepatitis C: interferon and ribavirin

Hepatitis C virus (HCV) infection is one of the commonest causes of liver cirrhosis and hepatocellular carcinoma. This review deals with treatment of chronic HCV infection with a combination of interferon and ribavirin. Recent trials have shown that approximately 40% of patients will clear HCV with combination treatment. This is an important advance in the treatment of this serious viral infection.

Hepatitis C

Hepatitis C virus (HCV) infection afflicts millions of people in the United States and worldwide. We examine the epidemiology of HCV infection, the molecular biology of the virus, the pathophysiology of infection, the clinical diagnosis and manifestations of infection, and the treatment of HCV infection.

Virus elimination and histologic improvement in patients with chronic hepatitis C treated with interferon alpha

We evaluated the elimination of hepatitis C virus (HCV) by means of interferon alpha (IFN-alpha) by investigating both positive- and negative-stranded RNA forms in the peripheral blood mononuclear cells and liver tissue. We also assessed the long-term histologic improvement accompanying viral clearance. We studied 20 persons with HCV whose serum aminotransferase levels remained normal for more than 1.5 years after IFN-alpha treatment withdrawal. The presence of HCV RNA in their peripheral blood and of both positive and negative strands in the peripheral blood mononuclear cells and liver tissue was investigated using the reverse transcription polymerase chain reaction method. We examined the histologic findings using the European classification and the histology activity index scoring system. In 16 of 20 patients, both strands disappeared from the possible reservoirs. The histologic findings indicated reduced activity, and histology activity index scores (1, 2, 3, and total) also showed significant improvement. We confirmed that IFN-alpha therapy can induce the elimination of HCV RNA from the conceivable HCV reservoirs and effect histologic improvement. Therapy with IFN-alpha is effective for treating chronic hepatitis C.

Long-term biochemical and virological response to natural interferon-alpha in patients with chronic hepatitis C

To determine the long-term response to interferon-alpha, 134 patients with chronic hepatitis C were followed for more than a year after therapy. Follow-up was stopped for 14 patients and 43 patients received retreatment. The remaining 77 patients were followed for 26-46 months, and 39 of them achieved long-term sustained alanine aminotransferase (ALT) normality. This normality was achieved in 35/38 short-term sustained responders, which was significantly higher (P < 0.001) than in the short-term relapsers (2/38) and the short-term nonresponders (2/44). Hepatitis C virus (HCV) RNA remained negative in 27 (73%) of 37 patients in the long-term sustained ALT normality group. However, only one (1.6%) of 63 long-term responders was negative for HCV RNA. The results of HCV RNA testing for the long-term period agreed with those at three to six months after therapy. Serum ALT levels during the first six months after therapy and HCV RNA testing at three to six months after therapy are important for predicting long-term sustained ALT normality and HCV RNA negativity.

Lack of benefit of escalating dosage of interferon alfa in patients with chronic hepatitis C

BACKGROUND & AIMS

In patients with chronic hepatitis C treated with interferon alfa, sustained normalization of alanine aminotransferase was observed in about 20%, and no predictive factor of response could be clearly identified. The aims of this study were to assess the efficacy of an escalating dose of interferon and to determine the predictive factors of response.

METHODS

Seventy-five patients were randomly assigned to two groups. Twenty-five patients received a dosage of 3 million units of recombinant interferon alfa-2b three times weekly for 24 weeks, and 50 patients received a dose that was increased to 5 million units at 8 weeks in nonresponders and to 10 million units 8 weeks later in persistent nonresponders. Multivariate analysis was performed to determine the features associated with response.

RESULTS

A sustained response was observed in 17% of the patients with constant dosage and in 19% of patients with an escalating dosage. Low pretreatment serum hepatitis C virus RNA levels and hepatitis C virus genotype were found to be independent predictive factors of sustained response.

CONCLUSIONS

In patients with chronic hepatitis C, an escalating dosage of interferon did not improve the overall rate of response. Low pretreatment serum hepatitis C virus RNA levels and genotype other than 1b were the only predictive factors of sustained response.