Maintenance interferon for chronic hepatitis C: more issues than answers?

Results of combination treatment with pegylated interferon and ribavirin in cirrhotic patients with hepatitis C infection

BACKGROUND

The treatment of hepatitis C patients with advanced cirrhotic liver disease remains challenging and data on the outcome of treatment for this patient group is limited.

RESULTS

Between September 2000 and August 2004, 61 cirrhotic patients started treatment with pegylated interferon and ribavirin (42 male, age range 29-69 years, 26 Asian). Forty-three (70%) patients were serum hepatitis C virus (HCV) RNA negative at the end of treatment and 24 (39%) achieved a sustained virological response (SVR). SVR was achieved for 35% (6/17) of patients with genotype 1, and for 39% (16/41) with genotype 3. Caucasians with genotype 3 demonstrated a higher cure rate (SVR 10/18 = 56%) than Asians (SVR 6/24 = 25%). Failure to achieve SVR was associated with lower platelet count, neutrophil count and albumin at baseline. Twenty patients suffered clinical or laboratory decompensation, five patients required hospitalization, and two patients died. Patients who experienced hepatic decompensation were older and had baseline characteristics associated with more advanced liver disease.

CONCLUSION

The treatment of patients with advanced HCV is challenging, although many treated patients achieve SVR. Significant toxicity is experienced and there is treatment-related mortality. This balance of efficacy and toxicity needs to be considered before commencing treatment.

Vascular binding, blood flow, transporter, and enzyme interactions on the processing of digoxin in rat liver

The roles of vascular binding, flow, transporters, and enzymes as determinants of the clearance of digoxin were examined in the rat liver. Digoxin is metabolized by Cyp3a and utilizes the organic anion transporting polypeptide 2 (Oatp2) and P-glycoprotein (Pgp) for influx and excretion, respectively. Uptake of digoxin was found to be similar among rat periportal (PP) and perivenous (PV) hepatocytes isolated by the digitonin-collagenase method. The Km values for uptake were 180 +/- 112 and 390 +/- 406 nM, Vmax values were 13 +/- 8 and 18 +/- 4.9 pmol/min/mg protein, and nonsaturable components were 9.2 +/- 1.3 and 10.7 +/- 2.5 microl/min/mg for PP and PV, respectively. The evenness of distribution of Oatp2 and Pgp was confirmed by Western blotting and confocal immunofluorescent microscopy. When digoxin was recirculated to the rat liver preparation in Krebs-Henseleit bicarbonate (KHB) for 3 h in absence or presence of 1% bovine serum albumin (BSA) and 20% red blood cell (rbc) at flow rates of 40 and 10 ml/min, respectively, biexponential decays were observed. Fitted results based on compartmental analyses revealed a higher clearance (0.244 +/- 0.082 ml/min/g) for KHB-perfused livers over the rbc-albumin-perfused livers (0.114 +/- 0.057 ml/min/g) (P < 0.05). We further found that binding of digoxin to 1% BSA was modest (unbound fraction = 0.64), whereas binding to rbc was associated with slow on (0.468 +/- 0.021 min(-1)) and off (1.81 +/- 0.12 min(-1)) rate constants. We then used a zonal, physiologically based pharmacokinetic model to show that the difference in digoxin clearance was attributed to binding to BSA and rbc and not to the difference in flow rate and that clearance was unaffected by transporter or enzyme heterogeneity.

Antiviral therapy in advanced chronic liver disease due to hepatitis C virus infection: pilot study

BACKGROUND

Antiviral therapy has not been adequately evaluated in patients with hepatitis C virus (HCV)-related advanced liver disease due to apprehensions of adverse events and intolerance. The titrable dose of interferon (IFN)-alpha and ribavirin was evaluated in a flexible regimen in a pilot study.

METHODS

Twenty-five patients with HCV-related advanced chronic liver disease received IFN-alpha 1-3 MIU daily with ribavirin 200-600 mg daily for 9 months-3 years. Careful assessment of safety, tolerability and efficacy was made.

RESULTS

Improvement in Child-Pugh score (8.4 +/- 1.2 to 7.4 +/- 2.0; P = 0.010) and serum albumin (3.0 +/- 0.5 g/dL to 3.6 +/- 0.5 g/dL; P = 0.007) occurred at follow up after antiviral therapy (median dose and duration: IFN-alpha 1.5 MIU/day for 12 months and ribavirin 400 mg/day for 7.5 months) as compared to baseline. Ascites regressed in 53% of patients (11/21). Thirteen patients (52%) lost HCV-RNA on therapy and eight (32%) achieved sustained virological response (SVR). Death occurred in three patients (12%) while on therapy, in two due to infection. No patient died in the responder group compared to five deaths (29%) in the non-responder group. However, there was no difference in the cumulative probability of survival in the sustained virological responder versus non-responder (P = 0.09). Adverse events were common (92%), but permanent withdrawal was required in only five patients (20%).

CONCLUSIONS

Low and titrable dose IFN-alpha and ribavirin therapy in patients with HCV-related advanced chronic liver disease achieves improvement in hepatic synthetic function, Child-Pugh score and ascites. However, close monitoring for serious adverse events is warranted.

Living donor liver transplantation in patients with hepatitis C

1. Hepatitis C virus (HCV) is the most common indication for living donor liver transplantation (LDLT). 2. Preliminary evidence suggests that HCV may occur earlier and may be more severe in LDLT recipients. However, current data is inconclusive relative to the impact of recurrent HCV on patient and graft survival in LDLT recipients. 3. Potential mechanisms for differences in severity of HCV in LDLT recipients are discussed. 4. LDLT remains a viable treatment option for selected patients with HCV.

Early virologic response to treatment with peginterferon alfa-2b plus ribavirin in patients with chronic hepatitis C

Interferon-based regimens for the treatment of chronic hepatitis C have become increasingly effective and are able to eradicate virus in more than one half of cases. Early identification of patients who will not respond is desirable because treatment might be stopped, thereby avoiding the expense and inconvenience of unnecessary therapy. We examined the accuracy of different degrees of viral inhibition during the early weeks of treatment (early virologic response [EVR]) with pegylated interferon alfa-2b and ribavirin (PEG/R) in identifying patients who would not respond to therapy. The best definition of EVR was a reduction in hepatitis C virus (HCV) RNA by at least 2 logs after the first 12 weeks of treatment compared with baseline. Between 69% and 76% of patients achieved this threshold, depending on the treatment regimen, and sustained virologic response (SVR) occurred in 67% to 80% of these patients. Patients who did not reach EVR did not respond to further therapy. If treatment had been stopped in patients without EVR, drug costs would have been reduced by more than 20%. In conclusion, early confirmation of viral reduction following initiation of antiviral therapy for chronic hepatitis C is worthwhile. It provides a goal to motivate adherence during the first months of therapy and a milepost at which to reassess the need for continued treatment. Most patients who are able to complete the first 12 weeks of therapy achieve EVR and have a high probability of SVR. Patients who fail to achieve EVR will not clear virus even if an additional 9 months of therapy is received. Therapy can be confidently discontinued in those cases.

Treatment of patients with hepatitis C and cirrhosis

Recommendations for treatment of hepatitis C in patients with cirrhosis are difficult. Few prospective studies have focused on treatment of patients with advanced disease, and response rates appear to be lower and serious side effects more frequent in patients with cirrhosis. In patients with compensated cirrhosis, combination therapy with interferon alfa (3 million units [MU] 3 times a week) and ribavirin (1,000 or 1,200 mg/d) results in a sustained virological response (SVR) in 33% to 41% of patients. Responses to combination therapy are not significantly higher using peginterferon alfa 2a (180 microg/wk; 43%) or peginterferon alfa 2b (1.5 microg /kg/wk; 44%) compared with standard interferon. In using peginterferon in combination therapy, the benefits of once weekly dosing need to be weighed against the higher risks of cytopenias and greater costs with the pegylated formulations. Combination therapy results in some degree of histological improvement even in patients who are virological non-responders. These findings provide the scientific basis for ongoing studies of maintenance therapy with peginterferon to prevent complications of cirrhosis in non-responder patients with hepatitis C. Recommendations for management of decompensated cirrhosis and of recurrent hepatitis C after liver transplantation are difficult because of limitations of data, most of which are derived from uncontrolled case series. Combination therapy is poorly tolerated in both groups and rates of response are low. Thus, while the medical need is great, treatment of patients with decompensated cirrhosis or with recurrent hepatitis C after transplantation should be undertaken cautiously and only within the confines of prospective clinical trials.

Treatment of recurrent hepatitis C

1. Treatment of established recurrent hepatitis C with interferon-alpha monotherapy does not achieve sustained virologic response (SVR). 2. Treatment of established recurrent hepatitis C with combination interferon plus ribavirin achieves SVR rates of 17% to 27%, but dropout rates approach 30%. 3. Pretransplant prophylaxis against recurrent hepatitis C with combination interferon plus ribavirin is poorly tolerated in patients with decompensated hepatitis C cirrhosis. 4. Posttransplant prophylaxis with combination interferon plus ribavirin prevents both recurrent viremia and hepatitis in 15% to 20% of patients, but dropout rates approach 50%. 5. Hepatitis C virus genotype is the best predictor of response to antiviral prophylaxis and treatment of recurrent hepatitis C. 6. Interferon-alpha therapy is not associated with an increased risk of allograft rejection in liver transplant recipients. 7. Ribavirin therapy is associated with increased hemolysis in liver transplant recipients. 8. Preliminary data suggest pegylated interferon monotherapy will have similar efficacy but better tolerability than combination interferon plus ribavirin. 9. In a recent study, posttransplant immunoprophylaxis with polyclonal hepatitis C immunoglobulin had no effect on recurrent viremia or hepatitis.

Management of chronic viral hepatitis before and after renal transplantation

Hepatitis C virus (HCV) infection is present in 2-50% of renal transplant recipients and patients receiving hemodialysis. Renal transplantation confers an overall survival benefit in HCV positive (HCV+) hemodialysis patients, with similar 5-year patient and graft survival to those without HCV infection. However, longer-term studies have reported increased liver-related mortality in HCV-infected recipients. Unfortunately, attempts to eradicate HCV infection before transplant have been disappointing. Interferon is poorly tolerated in-patients with end-stage renal disease and ribavirin is contraindicated because reduced renal clearance results in severe hemolysis. Antiviral therapy following renal transplantation is also poorly tolerated, because of interferon-induced rejection and graft loss. Although the prevalence of hepatitis B virus (HBV) infection has declined in hemodialysis patients and renal transplant recipients since the introduction of routine vaccination and other infection control measures, it remains high within countries with endemic HBV infection (especially Asia-Pacific and Africa). Renal transplantation is associated with reduced survival in HBsAg+ hemodialysis patients. Unlike interferon, lamivudine is a safe and effective antiviral HBV treatment both before and after renal transplantation. Lamivudine therapy commenced at transplantation should prevent early posttransplant reactivation and subsequent progression to cirrhosis and late liver failure. This preemptive therapy should also eradicate early liver failure from fibrosing cholestatic hepatitis. Because cessation of treatment may lead to severe lamivudine-withdrawal hepatitis, most patients require long-term therapy. The development of lamivudine-resistance will be accelerated by immunosuppression and may result in severe hepatitis flares with decompensation. Regular monitoring with liver function tests and HBV DNA measurements should enable early detection and rescue with adefovir. Chronic HCV and HBV infections are important causes of morbidity and mortality in renal transplant recipients. The best predictor for liver mortality is advanced liver disease at the time of transplant, and liver biopsy should be considered in all potential HBsAg+ or HCV+ renal transplant candidates without clinical or radiologic evidence of cirrhosis. Established cirrhosis with active viral infection should be considered a relative contraindication to isolated renal transplantation.

Maintenance therapy with gradual reduction of the interferon dose over one year improves histological response in patients with chronic hepatitis C with biochemical response: results of a randomized trial

BACKGROUND/AIMS

Our aim was to assess whether histological response was improved by continuing interferon-alpha (IFN) treatment in patients with chronic hepatitis C (HCV) with a biochemical response and no viral clearance after a usual IFN treatment.

METHODS

Fifty-seven patients with normal alanine aminotransferase (ALAT) levels and positive HCV RNA at the end of a 1 year IFN treatment were randomly assigned to either group 1 (n = 28) where IFN was stopped, or group 2 (n = 29) where IFN was continued for 1 more year with gradual reduction of the dose to keep serum ALAT activity below the upper limit of normal. Liver biopsies were obtained before, and then 6 months after the end of treatment.

RESULTS

Knodell's index improved between paired biopsies in group 2 (8.2+/-2.4 vs. 5.5+/-2.1), but not in group 1 (8+/-2.3 vs. 6.5+/-2). In post-treatment biopsies, the METAVIR activity score was significantly lower in group 2 than in group 1 (0.7+/-0.2 vs. 1.1+/-0.3, P < 0.05). In group 2, an improvement of the METAVIR fibrosis score was observed (1.3+/-0.4 vs. 1.1+/-0.2), whereas fibrosis progressed in group 1 (1.3+/-0.4 vs. 1.6+/-0.4).

CONCLUSIONS

Maintenance therapy by the minimal dose of IFN able to maintain biochemical response prevents histological progression in the sub-group of patients without virological response.