Induction interferon therapy in naïve patients with chronic hepatitis C: increased end-of-treatment virological responses but absence of long-term benefit

Combined effect of pegylated interferon α with adefovir on renal function in Chinese patients with chronic hepatitis B

BACKGROUND

Long-term safety of treatment with hepatitis B virus (HBV) polymerase inhibitors is a concern. Adefovir dipivoxil (ADV) and/or interferon alfa (IFN-α) therapies have previously been associated with impairment of renal function. Limited data are available on the safety of combination therapy with nucleos (t)ide analogues (NAs) and IFN-α. The aim of this analysis was to assess the renal function during combined therapy with pegylated interferon α-2b (PEG-IFN-α-2b) and ADV versus PEG-IFN-α-2b alone in patients with chronic hepatitis B (CHB).

METHODS

We performed a multicenter, prospective, open-label, randomized-controlled trial of renal function data to investigate the efficacy of 48 weeks of therapy with PEG-IFN-α-2b and ADV versus PEG-IFN-α-2b alone in 102 patients with CHB in Anhui, China. Glomerular filtration rates (GFRs) were calculated by Cockcroft-Gault (CG), abbreviated Modification of Diet in Renal Disease (MDRD) study, and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, and were tested by repeated-measures 1-way analysis of variance within groups. A linear mixed effects model for repeated measures was also used to evaluate the association between baseline information and estimated glomerular filtration rate (eGFR) changes overtime in all enrolled patients. The model considered the baseline age, sex, HBV DNA, aminotransferase, treatment group, time, and group-by-time interaction as fixed effects and incorporated random effects for individual subjects.

RESULTS

After 48 weeks of therapy and further 24 weeks of follow-up, the eGFR decreased both in patients given PEG-IFN-α-2b single therapy and combined therapy. Age, HBV DNA, and combined therapy were significant negative predictive factors for eGFR changes.

CONCLUSION

The incidence of renal adverse events in both groups was low, and the combination therapy may have delayed, but reversible renal impairment.

Review of consensus interferon in the treatment of chronic hepatitis C

Consensus interferon (CIFN) is an artificially engineered interferon that reflects most of the human genotype 1 interferons and shows a higher biological and antiviral capacity in vitro. It has been used internationally to treat patients with chronic hepatitis C (HCV) infection before pegylated IFN became available. To mimic the half-life of PEG-IFN it has to be administered on a daily basis. The gold standard in the treatment of hepatitis C is well established and recommended. Today patients are being treated with a combination therapy of pegylated IFN and ribavirin. Length and dosage of therapy depends on the genotype of the virus. Patients with genotype 1 and 4 and high viral load should be treated for 48 weeks; for patients with these genotypes along with either low viral load or early virological response, therapy for 24 weeks is sufficient. Patients with genotype 2 and 3 should be treated for up to 24 weeks. However, daily dosing of IFN-α, eg, CIFN, resulting in a higher cumulative dosage, might be beneficial and more efficacious in some chronic HCV-infected patients. Patients with genotype 1, having initially high viral load (>800,000 IU/mL) and showing advanced liver disease with progressive fibrosis or even cirrhosis comprise the difficult-to-treat in order to overcome the infection. This review summarizes and critically discusses the published data on the treatment of HCV with CIFN.

Randomized trial of high-dose interferon-alpha-2b combined with ribavirin in patients with chronic hepatitis C: Correlation between amino acid substitutions in the core/NS5A region and virological response to interferon therapy

The aim of this study was to compare the efficacy of high-dose interferon (IFN)-alpha-2b with standard dose of IFN-alpha-2b in combination with ribavirin (RBV) for patients with chronic hepatitis C virus (HCV) infection, and to investigate the predictive factors associated with virological response. Two hundred Japanese patients with high HCV viral load (>100 KIU/ml) were randomized to 6 or 10 mega units (MU) of 24-week IFN-alpha-2b with RBV. Predictive factors were investigated; including pretreatment amino acid (aa) sequences of the core region and the IFN-sensitive determining region (ISDR). The sustained virological response rate was not different in the two groups (24% vs. 30%) but the incidence of depression was significantly higher in the 10 MU group than 6 MU group (7% vs. 0%, P = 0.02). Younger age (<60) and HCV genotype (2a/b) were significant predictors of sustained virological response. In patients infected with genotype 1b, substitutions of core aa 70 and/or 91 were predictive for non-virological response (P < 0.001), and substitutions in the ISDR was observed frequently in virological responders. Early viral kinetics study showed that serum HCV core antigen decreased more slowly in both patients with aa 70 and/or 91 substitutions in the core and with absence of substitutions in the ISDR. In conclusion, the use of a higher dose of IFN-alpha-2b in combination with RBV did not improve virological response but resulted in higher incidence of depression. Amino acid substitutions in the core and ISDR are predictive of virological response to the therapy in patients with genotype 1b and high viral load.

High dose daily interferon-alpha induction and secondary adjunction of ribavirin in treatment-naive patients with chronic hepatitis C

OBJECTIVES

To evaluate in naive patients with chronic hepatitis C 1- the efficacy and safety of one month interferon alpha (IFN-alpha) induction regimen; 2- the potential virological benefit of a secondary adjunction of ribavirin among HCV RNA negative patients after 20 weeks of IFN therapy, with or without an initial 4-week IFN induction.

MATERIAL AND METHODS

151 naive HCV-RNA positive patients presenting with biopsy- proven chronic hepatitis C and elevated ALT were randomised in a 2: 1 ratio in two arms: IFN-alpha 3 MU thrice a week (tiw) for 24 weeks (non-induced patients); IFN-alpha 6 MU daily for two weeks, then 3 MU daily for two weeks then 3 MU tiw for 20 weeks (induced patients). At week 24, HCV-RNA negative patients were randomised to receive in addition or not ribavirin 1-1.2 g daily for 24 additional weeks. Induction efficacy was assessed on the early viral response (EVR) defined as undetectable HCV RNA at week 4 then week 20. Ribavirin efficacy was assessed on the proportion of maintained complete response until the end of follow-up, 24 weeks after discontinuation of treatment. Data were analysed on an intent-to-treat basis.

RESULTS

Efficacy of IFN-alpha induction: 104 patients were randomised to the non-induction group, 47 to the induction group. Gender, age, genotype distribution and HCV viral load at baseline did not differ significantly between the two groups. There was one treatment discontinuation because of adverse events in induced patients versus four in non-induced patients (P > 0.05). The 4 week EVR was significantly greater in induced patients in patients with HCV genotype 1, 4 or 5 (47% vs 12%, P=0.0002) only. There was no impact of induction in patients with HCV genotype 2 or 3. Efficacy of ribavirin: at week 24, 28 and 26 HCV-RNA negative patients were randomised to addition of ribavirin or not, respectively. Patients randomised to secondary additive ribavirin were more often HCV-RNA negative at the end of follow-up than patients treated with IFN-alpha alone: 18/28 (64%) vs 10/26 (39%); P=0.06. Among patients randomised to bitherapy, the relapse rate was significantly lower in patients with genotype 2 or 3 (0/12 vs 6/13, P=0.01) and not in those with genotype 1, 4 or 5 (5/11 vs 3/6, P=0.99).

CONCLUSION

A 4 week IFN-alpha induction significantly increases the EVR rate in patients with HCV genotype 1, 4 or 5. Late secondary adjunction of ribavirin to IFN-alpha for 6 months in HCV-RNA negative patients after 6 months of IFN-alpha significantly decreases the relapse rate in patients with HCV genotype 2 or 3, but not in patients with genotypes 1, 4 or 5.

Treatment with daily consensus interferon (CIFN) plus ribavirin in non-responder patients with chronic hepatitis C: a randomized open-label pilot study

BACKGROUND/AIMS

Therapeutic options for hepatitis C non-responder patients are limited.

METHODS

We initiated an open-label pilot study to investigate the efficacy of CIFN plus ribavirin on viral kinetics, sustained virological response (SVR), and histological response in hepatitis C non-responder patients. Seventy-seven patients were enrolled to receive CIFN given daily in combination with 1000/1200 mg ribavirin. An 8-week induction-dosing regimen of 18 microg CIFN, followed by 9 microg for 40 weeks was compared to 9 microg CIFN for 48 weeks. 90% of patients were infected with HCV-genotype 1.

RESULTS

Overall, 82% of the patients demonstrated an early virological response, 65% had an end-of-treatment response, and the SVR was 30%. Interferon/ribavirin non-responders demonstrated a SVR of 22%. Induction-dosing resulted in a greater first-phase HCV-RNA decay that, however, did not translate to better SVRs, presumably due to more dose modifications. High ALT, younger age, and second-phase viral kinetics were associated with SVR. Only sustained responders and relapse patients showed an improved liver histology.

CONCLUSIONS

Daily dosing of CIFN plus ribavirin may be a promising concept for selected non-responder patients before considering therapies which are anti-viral but not curative. However, motivation and compliance are requisites and a CIFN induction is not required.

Daily dose of interferon alpha-2b and ribavirin in treatment-naive patients with chronic hepatitis C virus genotype 1 infection: a randomised controlled study

OBJECTIVE

The treatment of patients with hepatitis C virus (HCV) genotype 1 infection remains disappointing.

METHODS

In 1999, we started a multicentre study comparing two regimens of recombinant interferon (IFN) alpha-2b plus ribavirin. Group A (90 patients) received ribavirin plus IFN alpha-2b 5 MU/day for 1 month (induction therapy) followed by IFN alpha-2b 5 MU thrice weekly for 5 months. Group B (85 patients) received ribavirin plus IFN alpha-2b 5 MU thrice weekly for 6 months. Responders in both arms received IFN alpha-2b 3 MU thrice weekly for a further 6 months. A follow-up evaluation was performed at 18 months.

RESULTS

One hundred and seventy-five consecutive treatment-naive patients with HCV genotype 1 infection were enrolled in the study. A sustained virological response (SVR) was obtained in 51 (29%) patients: 28 in group A (31%) and 23 in group B (27%). HCV-RNA clearance was greater at 3 months among patients who received induction therapy (57 vs 39%; p < 0.02). Age, sex, and initial viral load did not influence the achievement of a SVR. HCV clearance at the end of the study was lower in cirrhotic patients (3/26 vs 48/149; p < 0.05). The only SVR in patients with cirrhosis occurred in those from group A (p < 0.05). Both regimens were well tolerated.

CONCLUSIONS

This study confirms the low rate of SVR in treatment-naive patients with HCV genotype 1 infection treated with IFN alpha-2b plus ribavirin. A 4-week induction regimen was slightly superior to standard IFN alpha-2b plus ribavirin. Although the number of patients with cirrhosis was low, induction therapy seemed to be more effective in cirrhotics. Given its safety and tolerability, the induction regimen evaluated here may be a therapeutic option in treatment-naive patients with HCV genotype 1 infection.

Antiviral action of ribavirin in chronic hepatitis C

BACKGROUND & AIMS

In the patients with chronic hepatitis C, the addition of ribavirin to interferon (IFN)-alpha significantly increases the virologic responses. Our aim was to assess the antiviral action of ribavirin on hepatitis C virus (HCV) as a function of ribavirin pharmacokinetics and to evaluate the influence of this antiviral effect on IFN-alpha efficacy.

METHODS

Forty-five patients with chronic hepatitis C (genotype 1b) received various schedules of IFN-alpha and/or ribavirin administration. Frequent blood sampling was performed for HCV RNA kinetics and ribavirin pharmacokinetics assessment.

RESULTS

Ribavirin monotherapy induced a significant, moderate, early, and transient viral load decrease in approximately half of the patients. The occurrence of this effect was associated with longer ribavirin clearance half-lives and higher serum ribavirin concentrations. Ribavirin antiviral effect partly reduced the rebound preceding the second IFN-alpha injection in patients receiving standard IFN-alpha 3 times per week plus ribavirin. The magnitude of the rebound was inversely related to ribavirin concentrations. These patients subsequently experienced a slow, but significant, second slope of viral decrease and cleared HCV RNA. The addition of ribavirin to daily IFN-alpha monotherapy did not have any impact on the second phase of viral decline.

CONCLUSIONS

Ribavirin exerts a significant, moderate, and transient antiviral effect in a significant proportion of patients with chronic hepatitis C. The antiviral effect of ribavirin correlates with ribavirin pharmacokinetics and is partly responsible for the improved efficacy of the combination of standard IFN-alpha and ribavirin compared with IFN-alpha monotherapy by increasing the incidence of the initial response.

Chronic hepatitis C patients with a post-treatment virological relapse re-treated with an induction dose of 18 MU interferon-alpha in combination with ribavirin and amantadine: a two-arm randomized pilot study

Thirty-seven chronic hepatitis C patients with virological relapse (VR) after previous interferon-alpha (IFN) or IFN/ribavirin (Riba) therapy, were re-treated. Patients were randomized for either IFN/Riba and amantadine (Ama) including a 2-week initial high IFN induction course (18 MU IFN daily) (group A) or the same 2-week IFN induction course combined with Riba/Ama, followed by Riba/Ama without IFN (group B). Treatment duration for both groups was 24 weeks with a 24-week follow-up thereafter. The inclusion in group B was prematurely stopped because all patients (n = 10) relapsed within 2 weeks after stopping IFN. Therefore, all subsequent patients were included in group A (n = 27). In group A, 44% achieved a sustained virological response (SVR) and 29% of the patients with an end-of-treatment virological response had a VR again. Of all pretreatment characteristics, only genotype non-1 patients had a significantly higher chance of achieving SVR (P < 0.001). Of the characteristics during treatment only a negative hepatitis C virus (HCV)-RNA test result in transcription-mediated amplification (TMA) at week 6 had a high predictive value for SVR, 80% in all patients and 92% in genotype non-1 patients. In conclusion, hepatitis C patients with a VR to previous antiviral treatment can be successfully re-treated with IFN induction combined with Riba/Ama for only 6 months, when they have genotype non-1 and a negative HCV-RNA test result in TMA 6 weeks after the start of therapy. Riba/Ama combination therapy without IFN does not prevent VR after 2 weeks high IFN induction.

Sustained response to combination therapy in patients with chronic hepatitis C who failed to respond to interferon

BACKGROUND/AIMS

The best treatment for chronic hepatitis C patients who do not respond to interferon is still unknown. Reported rates of response to treatment vary as the result of heterogeneous definitions of non-responders and small study size.

METHODS

One hundred nineteen hepatitis C virus (HCV) RNA-positive non-responders to high-dose interferon monotherapy received alpha-interferon, 5 MU tiw plus oral ribavirin, 1000-1200 mg/day for 48 weeks (Group A, n=74) or alpha-interferon, 5 MU daily for 4 weeks, followed by 5 MU tiw plus oral ribavirin, 1000-1200 mg/day for 44 weeks (Group B, n=45) according to the Institution where they were followed. Persistently normal alanine aminotransferase and negative HCV RNA up to 72 weeks from treatment onset defined a sustained response.

RESULTS

Eighteen patients discontinued treatment (13 developed anemia, two mucositis, one granulocytopenia; two were dropouts), none for serious adverse events. There were 24 (20%) sustained responders, with similar final response rates in Groups A and B. Sustained response was more frequent in patients aged </=40 years (36% vs. 13%; P=0.006) and in those with non-1 genotype (44% vs. 14%; P=0.002). Among genotype 1 patients, the younger ones showed higher response rates (32% vs. 7%; P=0.005). Compared with patients harboring non-1 genotypes, the odds ratio of being a non-responder was 1.68 (confidence interval (CI): 0.53-5.37; P=0.381) in younger genotype 1 patients and 9.53 (CI: 2.84-32; P<0.001) in older genotype 1 patients.

CONCLUSIONS

Chronic hepatitis C patients who are non-responders to interferon monotherapy and infected by non-1 genotypes should undergo re-treatment with combination therapy. Treatment should be extended to younger genotype 1 patients who are more susceptible to liver disease worsening because of longer life expectancy and have a higher probability of being long lasting responders than their older counterparts.

Mathematical modeling of viral kinetics: a tool to understand and optimize therapy

One theme that continues to emerge from these studies is the relevance and need for a strong IFN effectiveness. In the prediction studies, the importance of IFN effectiveness for eventual clearance of the virus is present. In the study by Layden et al, the relevance of the viral load at the end of the first phase and IFN effectiveness, to the subsequent second-phase viral decline, is discussed. In the recently developed triphasic model by Bergmann et al, it is illustrated how, theoretically, the viral load at the end of the first phase could impact the second-phase viral decline and eventual clearance of the virus. And, in the investigation into the difference in viral dynamics between African Americans and Caucasians, it appears that a strong effectiveness and first-phase log drop is crucial for virus eradication. More work needs to be completed to understand better why the effectiveness is so crucial for elimination of the virus, and why the effectiveness varies so significantly from one person to another, or from one genotype to another. In a rather short time, the study of viral kinetics has improved our understanding of HCV infection, especially in relation to treatment response. Information has been gleaned on the rapid turnover and clearance rate of the virus, the mode of action of IFN, and the dose-dependence of IFN in inhibiting viral production. Such information has been used to challenge the way we treat patients, understand the difference between nonresponders and responders, gain insight into possible mechanisms of treatment resistance, and predict treatment response. As newer drugs emerge, viral kinetic studies should be able to shed light on the dose-dependent efficacy and mode of action of these newer forms of therapy. The use of kinetics needs to be extended to other areas, such as the study and treatment of acute HCV infection as well as following liver transplantation (see article by Drs. Pawlotsky and Rosen). If the past is any indication of the usefulness of mathematical modeling and kinetics in the study of viruses, continued employment of these tools will only prove beneficial.

Hepatitis C viral dynamics: basic concept and clinical significance

Viral dynamics is a concept analyzing the time course of treatment-induced changes in blood virion concentration (kinetics) to derive conclusions of where, when and how in the living organism virions are produced or eliminated. Originally applied to human immunodeficiency virus type 1 and hepatitis B virus, it has elucidated mechanisms of antiviral therapy in hepatitis C virus infection as well. This review summarizes key aspects of mathematical modeling as well as important clinical applications, namely induction therapy and prediction of virologic response to treatment. Furthermore, limitations of currently available quantitative assays will be discussed.

Induction therapy with consensus interferon (CIFN) does not improve sustained virologic response in chronic hepatitis C

In patients infected with hepatitis C virus (HCV) genotype 1, sustained viral response (SVR) averages 10-40% depending on treatment regime. It has been proposed that high dose daily interferon (IFN) therapy early in therapy (induction dosing) may enhance SVR. In the present study we examined this issue and also assessed whether one could predict SVR and non-SVR, based on viral kinetics during the first month of induction therapy. End of treatment response and SVR was determined in 173 HCV infected patients who were treated with different induction doses of consensus interferon (CIFN) for one month followed by 11 months of standard 9 microg of CIFN thrice weekly (TIW). The second phase decline slope was calculated by log-linear regression on weekly measurements of serum HCV RNA during the first 7-28 days of treatment; rapid viral response (RVR) during the first month of induction dosing was defined as a decline of > 0.3 log copies/mL/week. Overall, SVR occurred in 11% of genotype 1 infected patients and 41% of patients with nongenotype 1. High dose induction therapy did not increase the rate of SVR, in either genotype 1 or genotype 2/3 infected patients. No patient without a RVR during the first month had SVR, while SVR occurred in 55% of the patients with RVR. RVR was the best predictor of SVR using multivariate analysis. These results indicate that induction dosing with CIFN does not improve SVR rates. They also suggest that early viral kinetics during the first month of therapy can predict non-SVR and thus save a patient a year long treatment which is fraught with side-effects and significant cost.