Biochemical and viral response to consensus interferon (CIFN) therapy in chronic hepatitis C patients: effect of baseline viral concentration. Consensus Interferon Study Group

Optimum predictors of therapeutic outcome in HCV patients in Pakistan

Hepatitis C virus (HCV) constitutes a major public health issue in Pakistan. Interferon α and ribavirin is used widely in routine practice in HCV infected patients in Pakistan.Treatment prediction is an important tool in therapy management. The present study aims to evaluate trends of predictive variables of treatment outcome in patients with different genotypes. The analysis comprised of 921 patients infected with different HCV genotypes. All the patients received IFN α-2b combined with ribavirin for 24 weeks. Overall, 60.2% patients achieved Sustained virologic response (SVR). In females sustained virologic response (SVR) was higher in age group <40 years (77.2%) than ≥40-50 years (60%) but in male SVR was almost equal in both age groups. We also found higher SVR with low pretreatment viral load (72.4%, P < 0.0001). Sustained Virologic Response in genotype 3a was 63.1%, 3b was 55%, 1a was 36.3% and 1b was 35% 3a +3b was 55.0% and 1a+3a was 42.9%. According to multivariable logistic regression analysis age < 40 years (2.0; 95%CI, 1.49-2.84; P = 0.0001), low pretreatment RNA level<800,000 IU/ml (4.0; 95%CI, 2.64-6.17; P = 0.0001), early virologic response at week 12 (12.3; 95%CI, 8.18-18.58; P < 0.0001) and non-fatty liver (2.5; 95%CI, 3.6-6.2; P = 0.005) showed significance for SVR. Nucleotide substitution in 5'UTR before treatment failed to show any characteristic pattern that has correlation with sustained response. Subtype 3a showed 95% presence among patients with age <40 years while older patients showed 79.9%.

Analysis of variables and interactions among variables associated with a sustained virological response to pegylated interferon alfa-2a plus ribavirin in hepatitis C virus genotype 3-infected patients

BACKGROUND

The recommended standard therapeutic regimen for chronic hepatitis patients with hepatitis C virus (HCV) genotype 3 is pegylated interferon plus ribavirin for 24 weeks. The aim of the present study was to evaluate treatment efficacy and variables predictive of treatment success, interactions among variables contributing to a response to therapy, and the utility of the rapid virological response (RVR; week 4 virological response) to predict treatment outcomes in HCV genotype 3-infected patients in routine clinical practice.

METHODS

We prospectively studied baseline and during-treatment factors associated with a sustained virological response (SVR) in HCV genotype 3-infected patients who received pegylated interferon alfa-2a (PEG-IFN α2a) 180 μg/week plus ribavirin 800 mg daily for 24 weeks and who were followed for 24 weeks after the completion of treatment.

RESULTS

Four hundred and twenty-six treated patients were included in the analysis; 320 (75.1%) showed an SVR. The following factors were assessed for their ability to predict SVR by means of univariable and multivariable logistic regression analysis: patient age, sex, pre-treatment viral load, pre-treatment alanine aminotransferase (ALT), body mass index (BMI), and RVR. Four factors - age, pre-treatment viral load, pre-treatment ALT, and RVR - were statistically significant predictors of SVR (p<0.05) in the univariable analysis. Factors showing a significant association with SVR were assessed by multivariable logistic regression analysis. In the multivariable analysis, independent factors associated with SVR were the attainment of RVR (odds ratio (OR) 11, 95% confidence interval (CI) 6.15-20.69; p<0.0001), patient age ≤40 years (OR 4.2, 95% CI 2.30-7.96, p<0.0001), and a low pre-treatment viral load (≤8 × 10(5) IU/ml; OR 3.4, 95% CI 1.87-6.25; p<0.0001). The effect of RVR in patients aged >40 years was more pronounced than in those aged ≤40 years: 81.1% of patients aged >40 years who achieved an RVR had an SVR, whereas only 7.5% of patients aged >40 years who did not achieve an RVR had an SVR (p<0.05).

CONCLUSIONS

RVR is an independent variable that is predictive of SVR. Moreover older patients (>40 years) who achieve an RVR are likely to have an SVR, while patients who do not achieve an RVR and who have a high pre-treatment viral load (>8 × 10(5) IU/ml) are unlikely to have an SVR.

Pharmacokinetics, tissue distribution, excretion, and antiviral activity of pegylated recombinant human consensus interferon-α variant in monkeys, rats and guinea pigs

The study aims to characterize the pharmacokinetic, tissue distribution, excretion, and antiviral activity properties of a novel pegylated recombinant human consensus interferon-α variant (PEG-IFN-SA) following a single subcutaneous administration to monkeys, rats and guinea pigs. Studies included: (1) pharmacokinetic properties of PEG-IFN-SA and comparison with those of non-pegylated IFN-SA in rhesus monkeys and rats; (2) tissue distribution and urinary, fecal, and biliary excretion patterns of (125)I-PEG-IFN-SA in guinea pigs; and (3) antiviral activity assessment of PEG-IFN-SA in cynomolgus monkeys. The pegylated protein exhibited improved pharmacokinetic properties compared to IFN-SA in both monkeys and rats, with a 12-fold and 15-fold increase in elimination half-life, and a 100-fold and 10-fold decrease in serum clearance, as well as a 2.5-fold and 10-fold increase in the time to reach peak serum concentration, respectively. (125)I-PEG-IFN-SA was found to be distributed to most of the tissues examined and has character of targeting special distribution, and urinary appeared to be a major route for the excretion of PEG-IFN-SA in guinea pigs. Serum sample analysis from PEG-IFN-SA-treated monkeys showed dose-dependent antiviral activity for one week. These findings demonstrate that pegylation of IFN-SA results in more desirable pharmacokinetic properties, enhanced drug exposure and sustained-efficacy of in vivo antiviral action.

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.

Evaluation of prognostic factors for Peg Interferon alfa-2b plus ribavirin treatment on HCV infected patients in Pakistan

The effective standard therapeutic regimen for patients with chronic hepatitis C is pegylated interferon plus ribavirin. The efficacy of treatment in chronic hepatitis C is defined as absence of detectable virus at six months after treatment. Analysis of patient dependent and virus related factors that enable us to predict the response to antiviral treatment is very important. We prospectively studied 403 patients who received PEG-IFN alpha-2b 1.5 μg/kg/body weight plus ribavirin. Treatment was administrated for 24 weeks and 48 weeks for hepatitis C virus (HCV) genotypes 3 and 1, respectively. Out of 403 treated patients, 301 patients (74.7%) showed a sustained virologic response (SVR). Seven variables (age, sex, ethnic group, pretreatment viral load, HCV genotyping and pretreatment ALT) were chosen as possible predictors of SVR and were analysed by means of univariable and multivariable logistic regression analysis. Five variables were statistically significant (p<0.005) on univariable analysis: age, ethnic group, pretreatment viral load, response rate at week 4, and HCV genotype. In multivariable analysis independent factors associated with SVR were low pretreatment viral load (1.97; 95%CI, 1.06-3.66; p=0.03) and attainment of rapid virological response (RVR) (7.19; 95%CI, 4.15-12.45; p<0.001). Our findings support the association between viral load and SVR to PEG-IFN-alpha-2b plus ribavirin therapy. No achievement of RVR is an unfavorable marker for SVR. These findings suggest that all patients considered for treatment should have quantification of serum HCV RNA levels. The result can be used to counsel patients on the likelihood of achieving SVR and may influence the patient's decision on treatment. Future studies should confirm and explore this observation in other ethnic groups and in relation to HCV genotypes 1 and 3.

Efficacy and cost-effectiveness of consensus interferon monotherapy with high-dose induction for hepatitis C patients with genotype 2

OBJECTIVE

Several treatment strategies for patients with chronic hepatitis C have been compared mainly in terms of their efficacy, and it has been found that pegylated interferon (IFN) plus ribavirin has become the standard therapy, but aged patients may not tolerate ribavirin and the cost-effectiveness of treatment should also be further considered. We conducted a study to evaluate the efficacy, safety, and cost-effectiveness of consensus IFN monotherapy with high-dose induction for patients with chronic hepatitis C in clinical practice.

MATERIAL AND METHODS

We consecutively enrolled 104 patients with chronic hepatitis C. Patients were scheduled to receive 12 or 18 μg of consensus IFN daily for 2 weeks, then three times a week for 22 weeks. Efficacy, safety, and cost-effectiveness were assessed. A Markov model was developed to investigate cost-effectiveness in patients with chronic hepatitis C treated by different IFN-based treatment strategies.

RESULTS

Of the 104 study patients, a sustained virological response (SVR) was achieved in 66 (63%). Logistic regression analysis revealed that genotype 2, lower hepatitis C virus RNA levels, and patient age were independently associated with SVR. The response rate was significantly higher in patients with genotype 2 (51/66, 77%) versus genotype 1 (15/38, 40%). Cost-effectiveness analysis in patients with genotype 2 revealed that high-dose induction with consensus IFN monotherapy was as highly cost-effective as pegylated IFN plus ribavirin.

CONCLUSION

Consensus IFN monotherapy with high-dose induction shows high efficacy and cost-effectiveness in chronic hepatitis C patients with genotype 2 infection. Thus, it may be a reliable alternative in aged patients and for those excluded from standard combination therapy.

Comparative efficacy and overall safety of different doses of consensus interferon for treatment of chronic HCV infection: a systematic review and meta-analysis

BACKGROUND

About one-half of patients with hepatitis C genotype 1 and one-third with genotype 2/3 have treatment failure with peginterferon alpha and ribavirin. Consensus interferon (CIFN) is an option for retreatment of these patients.

OBJECTIVE

To summarize comparative safety and efficacy of different regimens of CIFN for the treatment of patients with chronic hepatitis C infection.

DATA SOURCE

Medline, Scopus, ISI, and Cochran Central Register of Clinical Trials were used.

STUDY ELIGIBILITY CRITERIA

Randomized clinical trials (RCTs) were eligible for inclusion in the study.

PARTICIPANTS

HIV and HBV seronegative patients with positive HCV-RNA during the 6 months before the start of the study were eligible for inclusion.

INTERVENTIONS

Different regimens of CIFN were studied.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies were appraised based on methods of random sequence generation, allocation concealment, and blinding. The random effects model of DerSimonian and Laird was employed to run the meta-analysis. The end-point was sustained virological response (SVR).

RESULTS

Data of 10 RCTs including 1,600 subjects were extracted. High daily induction dose regimen of CIFN did not yield a higher rate of SVR than low daily induction dose treatment regimen, RR = 0.83 (95% CI 0.58-1.17). A dose of 9 μg thrice weekly (tiw) was associated with a significantly higher rate of SVR compared with 3 μg [RR = 3.14 (95% CI 1.68-5.58)][Symbol: see text]. Withdrawal rate was similar [RR = 1.28 (95% CI 0.65-2.50)] but dose modification was higher in 9 μg [RR = 3.22 (95% CI 1.08-9.60)]. A dose of 18/15 μg tiw was not more effective than 9 μg over a similar treatment duration [RR = 1.02 (95% CI 0. 87-1.19)].

LIMITATIONS

Limitations include inadequate reporting of methodological information and side effects, lack of publication bias assessment due to the small number of studies in each analysis.

CONCLUSIONS

High dose daily induction therapy with CIFN is not superior to low dose therapy in terms of SVR. It seems that 9 μg tiw is the optimal treatment dose of CIFN for treatment of HCV infection. Optimal duration and safety profile of CIFN therapy have yet been elucidated.

Antinuclear antibody positivity in patients with chronic hepatitis C: clinically relevant or an epiphenomenon?

BACKGROUND

Serum autoantibodies such as antinuclear antibody (ANA) are frequently detected in patients with chronic hepatitis C virus (HCV) infection, but its relevance is a matter of discussion.

AIM

To assess the association of ANA positivity with clinical and histological features, and with the outcome of antiviral therapy in patients with HCV infection.

METHODS

Baseline samples from patients with hepatitis C treated with interferon and ribavirin were tested for ANA positivity by indirect immunofluorescence.

RESULTS

The mean age was 48.3+/-11.1 years and 56% were men. Among 234 included patients, 22 patients (9.4%) were positive for ANA. These patients showed significantly higher median alanine aminotransferase level (3.52 vs. 2.39 x upper limit of normal, P=0.009) when compared with ANA-negative patients. Fibrosis stage and necroinflammatory grading were not influenced by ANA positivity. Sustained virological response (SVR) rates were similar between ANA-positive and ANA-negative patients (27 vs. 29%, P=0.882). Alanine aminotransferase flares (> or = 1.5-fold the baseline) during treatment were observed in 28 patients (12%), irrespective of the presence of ANA and without any clinical significance.

CONCLUSION

Among HCV patients, ANA positivity seems to represent an immunological epiphenomenon. It neither influences clinical, biochemical, and histological features of chronic hepatitis C nor predicts response to antiviral treatment.

Impact of Double-Filtration Plasmapheresis in Combination with Interferon and Ribavirin in Living Donor Liver Transplant Recipients with Hepatitis C

Double-filtration plasmapheresis (DFPP) selectively removes high molecular weight substances including hepatitis C virus (HCV). Four live donor liver transplantation (LDLT) recipients with HCV received combination therapy with low-dose interferon (IFN) and ribavirin with DFPP. Three patients underwent this therapy for prophylaxis of HCV recurrence, and one for treating fibrosing cholestatic hepatitis (FCH). The combination therapy and DFPP decreased HCV RNA levels to 8.2% +/- 2.9% and 0.7% +/- 0.5% by the 5th and 30th day of treatment, respectively. Three patients who underwent DFPP for prophylaxis showed no evidence of HCV recurrence for >1 year after treatment. The patient whose graft showed FCH, recovered dramatically after the DFPP treatment. DFPP appeared to be effective in reducing HCV viremia and preventing HCV recurrence in patients with high HCV RNA levels after LDLT. Moreover, it may become a rescue therapy for FCH in a liver transplant recipient with hepatitis C.

Induction therapy with twice-daily interferon-beta does not improve the therapeutic efficacy of consensus interferon monotherapy for chronic hepatitis C

We examined therapeutic superiority of induction therapy with twice-daily IFN-beta (3X2=6 million units/day) onto 6-months consensus interferon monotherapy for chronic hepatitis C. Patients were randomly assigned to monotherapy without (group I, n=16) and with induction therapy (group II, n=12). The mean age of group II was older than that of group I, and other baseline condition was not statistically significant. Sustained virological response (SVR) rates of group I and II were 81.3% (13/16) and 58.3% (7/12), respectively (p=0.365). SVR rates in patients with genotype 1b were 66.7% (4/6) and 0% (0/2, because of drop-out), and those with high viral load were 70% (7/10) and 75% (6/8) in group I and II, respectively (p=1.000). Drop-out rates during therapy were 6.3% (1/16) and 33.3% (4/12) in group I and II, respectively (p=0.176). Age less than 50 years was the only independent factor that was shown by multivariate logistic model analysis to be associated with a sustained virological response. Although randomization failed to produce and equal age distribution in the two groups in this study, our results suggest that induction therapy with twice-daily IFN-beta has no beneficial effect on the efficacy of monotherapy with consensus interferon, probably because of the higher drop-out rates and incidence of adverse reactions with induction therapy.

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.

Racial differences in response rates to consensus interferon in HCV infected patients naive to previous therapy

BACKGROUND

Despite a rapid evolution in the treatment of Hepatitis C (HCV), response to therapy among different racial and ethnic groups is poorly characterized.

STUDY

Three hundred and thirty HCV infected patients naive to previous therapy received induction therapy followed by every other day dosing with consensus interferon. Greater than 30% of treated patients were not white, allowing comparison of response among different races/ethnicities and genotypes.

RESULTS

An overall sustained virologic response (SVR) was achieved in 24% of white, 12% of Hispanic, and 4% of AA patients (P = 0.003 white vs. non-white). 15% of white and 13% of Hispanic Genotype 1 patients achieved an SVR; 2% of AA patients achieved an SVR (P = 0.001 AA vs. non AA). Surprisingly, an SVR of 50% and 40% was achieved by AA and White Genotype 2 patients, compared with 10% in Hispanic patients (P = 0.001).

CONCLUSION

Significant differences in response rates to induction therapy followed by every other day dosing with consensus Interferon was observed when comparing white to non-white patients, particularly when comparing response rates by genotype. These observations reinforce the requirement that prospective studies that enroll a significant percentage of non-whites are needed to adequately characterize response rates to anti-HCV directed therapy.

A randomized trial of consensus interferon in combination with ribavirin as initial treatment for chronic hepatitis C

BACKGROUND/AIMS

The aim of the present, open-labeled, randomized study was to determine the efficacy and safety of different doses of consensus interferon plus ribavirin in the initial treatment of chronic hepatitis C.

METHODS

One hundred and one genotype 2/3 patients were randomized to receive 9 mcg (group A, n=48) or 18 mcg (group B, n=53) of consensus interferon thrice weekly plus ribavirin (1000/1200 mg/daily) for 24 weeks and 92 genotype 1 patients to receive 9 mcg (group C, n=47) or 18 mcg (group D, n=45) of consensus interferon plus ribavirin for 48 weeks.

RESULTS

In an intention-to-treat analysis, the sustained virologic response at 24-week follow-up was 69% and 66% for group A and B (P=0.77) and 40% and 36% for group C and D (P=0.63). The overall sustained response was 67% and 38% in patients with genotype 2/3 and 1, respectively. Among genotype 1 patients the sustained virologic response was 39% and 41% for high or low baseline viremia levels.

CONCLUSIONS

Higher consensus interferon dose does not increase sustained virologic response. Naive genotype 1 patients may achieve significant response rate of approximately 40% if treated with 9 mcg of consensus interferon plus ribavirin for 48 weeks.

Dynamics of alanine aminotransferase during hepatitis C virus treatment

Studies of the kinetics of hepatitis C virus (HCV) decline during interferon (IFN)-based therapy have led to insights into treatment efficacy. However, the kinetics of serum alanine aminotransferase (ALT), an enzyme used as a surrogate of liver damage, have not been closely monitored, and it is not known if they correlate with those of HCV RNA. Here we describe the associations between ALT and HCV dynamics. We analyzed 35 patients treated daily with 10 mIU IFN-alpha 2b with or without ribavarin for 28 days followed by standard IFN/ribavirin therapy. Patients exhibited 4 patterns of ALT change: (1) exponential decay of ALT, (2) transient increase in ALT followed by a decrease to pretreatment or normal levels, (3) increase in ALT to a new level, and (4) no significant change. By simultaneously modeling HCV and ALT dynamics, we successfully fit the observed changes. We found ALT decays with t(1/2) = 12.7 hours. The transient increase in ALT observed in some patients suggested a mild hepatotoxic effect of IFN. However, patients with a smaller initial ALT increase achieved higher rates of viral negativity by week 72 (P =.02). The week-4 ALT decline correlated with the HCV log drop (P =.006) and the efficacy of therapy (P =.025). In conclusion, our results suggest the use of ALT as a surrogate marker for treatment effect in patients with elevated ALT.

Effect of alpha 2b interferon on inducement of mIL-2R and treatment of HCV in PBMC from patients with chronic viral hepatitis C

AIM: To study the level of membrane interleukin-2 receptor (mIL-2R) on surface of peripheral blood mononuclear cells (PBMC) and the therapeutic efficacy of alpha 2b interferon on the treatment of HCV-RNA in PBMC of patients with chronic hepatitis C and to compare the negative rates of HCV-RNA in PBMC, HCV-RNA and anti-HCV in serum.

METHODS: Before and after treatment of alpha 2b interferon, the level of mIL-2R of patients with chronic hepatitis C was detected by biotin-streptavidin (BSA). The therapeutic group (26 cases) was treated with alpha 2b interferon (3 MU/d) and control therapeutic group (22 cases) was treated with routine drugs (VitC, aspartic acid). The total course of treatment with alpha 2b interferon and routine drug was six months and per course of the treatment was three months. The levels of HCV-RNA in PBMC, HCV-RNA and anti-HCV in serum were detected before and after a course of the treatment.

RESULTS: Before and after treatment of alpha 2b interferon and routine drugs, the levels of mIL-2R in silence stage were (3.44 ± 0.77)% and (2.95 ± 0.72)%, the levels of mIL-2R in inducement stage were (33.62 ± 3.95)% and (30.04 ± 3.73)%. There was a significant difference between two groups (P < 0.01-P < 0.05). After treatment of alpha 2b interferon with 3 MU/d for two courses of the treatment, the total negative rates of HCV-RNA in the PBMC and HCV-RNA, anti-HCV in serum were 42.31% (11/26), 57.69% (15/26), 65.38%(17/26) respectively. After the treatment of routine drug, the negative rates of HCV-RNA in PBMC and HCV-RNA, anti-HCV in serum were 13.64% (3/22), 22.73% (5/22), 27.27% (6/22) respectively. There was high significant difference in the group treated with alpha 2b interferon and the group treated with routine drugs (P < 0.01-P < 0.05).

CONCLUSION: The mIL-2R can be induced by alpha 2b interferon during the treatment. The alpha 2b interferon has a definite effect on the treatment of HCV-RNA in PBMC. The curative effect of alpha 2b interferon is better than that of the routine drugs.

Genetically modified interferon: is there a consensus yet?

The treatment of patients with chronic hepatitis C virus infection has evolved during the last decade from interferon monotherapy to combination therapy with interferon and ribavirin. National and international guidelines recommend either 6 or 12 months of interferon/ribavirin combination therapy depending on the pre-treatment virological status of the patient. However, the choice for second-line treatment of patients who do not achieve sustained viral clearance with combination therapy has yet to be defined. This commentary examines previously published studies of the use of consensus interferon for hepatitis C virus infected patients. The characteristics of the treated populations and response to treatment are examined. The current and potential roles for this type of interferon in the treatment of hepatitis C virus infection are considered.

Interferon alfacon-1: a review of its pharmacology and therapeutic efficacy in the treatment of chronic hepatitis C

Interferon alfacon-1 (consensus interferon) is a non-naturally occurring, synthetic, type 1 interferon (IFN)alpha that is used for the treatment of patients with chronic hepatitis C. The efficacy of subcutaneously administered interferon alfacon-1 has been demonstrated in clinical trials during the treatment of LFN-naive patients (interferon alfacon-1 9microg 3 times a week for 24 weeks) and retreatment of nonresponders and relapsers to previous interferon therapy (interferon alfacon1 15 microg 3 times a week for up to 48 weeks). Higher and more frequent interferon alfacon-1 dosages have also been investigated. Results from a pivotal double-blind randomised trial in 704 patients with chronic hepatitis C showed that interferon alfacon-19 microg 3 times a week achieved virological and biochemical response rates of 34.9 and 42.2%, respectively, at treatment end-point (week 24). Sustained virological and biochemical responses (week 48) were reported in 12.1 and 20.3% of the patients, respectively. In general, response rates in recipients of interferon alfacon-1 9 microg 3 times a week were similar to those achieved with IFN-alpha2b 3 MIU 3 times a week. However, interferon alfacon-1 was more effective in the subgroup of patients infected with hepatitis C virus (HCV) genotype 1 at end-point (virological response, 24 vs 15%; p < 0.05) and post-treatment observation period (8 vs 4%) although the difference between treatment groups was statistically significant only at treatment end-point. The sustained virological response rate achieved in patients with high baseline levels of serum HCV RNA receiving interferon alfacon-1 was statistically superior to that exhibited in the IFN-alpha2b treatment group (7 vs 0%; p < Interferon alfacon-1 also showed efficacy during the retreatment of non-responders and relapsers to previous IFN therapy in a large nonblind multicentre trial. Sustained virological response (week 72) was observed among 13 and 58% of nonresponders and relapsers, respectively, after 48 weeks of treatment with interferon alfacon-1 15 microg 3 times a week. Interferon alfacon-1 has been generally well tolerated in clinical trials. As with other IFNs, adverse events were reported frequently but were usually considered of mild to moderate severity, decreased with time and caused a small percentage of patients to withdraw from the treatment. Fever, fatigue, arthralgia, myalgia, headache and rigors were the most frequently reported adverse events. Psychiatric adverse events appeared to be dose-related and caused the majority of treatment withdrawals.

CONCLUSION

Interferon alfacon-1 is generally well tolerated and is an effective agent in the treatment of patients with chronic hepatitis C. Comparative data from a pivotal randomised trial indicate that the drug has at least equivalent efficacy to IFNalpha-2b, and a statistically significant advantage was demonstrated at treatment end-point in patients infected with HCV genotype 1. A number of ongoing trials with interferon alfacon-1 are evaluating issues such as the optimal dosage regimen and duration of therapy in an effort to improve sustained virological response to therapy, a goal for IFNs in general.

Depression, fatigue, and functional disability in patients with chronic hepatitis C

OBJECTIVE

To examine the extent to which fatigue and functional disability correlate with severity of depressive symptoms in patients with chronic hepatitis C.

METHODS

Fifty patients with chronic hepatitis C were evaluated using structured psychiatric interviews and standardized rating instruments.

RESULTS

Fourteen (28%) of patients had current depressive disorders. Depressed and nondepressed patients did not differ with regard to demographics or hepatic disease severity. Severity of depressive symptoms was highly correlated with fatigue severity while measures of hepatic disease severity, interferon treatment, and severity of comorbid medical illness were not. Severity of depressive symptoms was associated with functional disability and somatization.

CONCLUSIONS

Disability and fatigue are more closely related to depression severity than to hepatic disease severity. Antidepressant treatment trials in patients with hepatitis C are indicated to determine whether improvement in depressive symptoms leads to improvement in fatigue and functioning.

Spectrum of virus inhibition by consensus interferon YM643

The spectrum of viruses inhibited by a genetically engineered consensus interferon (IFN) YM643 (interferon alfacon-1) was evaluated using a cytopathic effect inhibition assay or plaque inhibition assay for five DNA viruses and 12 RNA viruses. This activity was compared to that of natural IFN-alpha derived from Namalwa lymphoblastoid cell line [IFN-alpha (Namalwa)]. The viruses inhibited by both IFNs were herpesvirus types 1 and 2, human cytomegalovirus, varicella-zoster virus, vesicular stomatitis virus, yellow fever virus, bovine viral diarrhoea virus, Semliki Forest virus, western equine encephalitis virus, encephalomyocarditis virus, rhinovirus type A, respiratory syncytial virus, Newcastle disease virus and influenza virus type A (H1N1). Neither IFN inhibited coxsackie virus B1, reovirus type 3 or vaccinia virus in the experimental conditions used. The specific activity of YM643 in human cells generally ranged from 3.6x10(7) to 2.1x10(9) IU/mg, which was greater than that of IFN-alpha (Namalwa), which ranged from 3.1x10(6) to 4.6x10(8) IU/mg against all sensitive viruses, except human cytomegalovirus and rhinovirus type 1A, which displayed approximately equal sensitivity to both IFNs. Significantly, the potency of YM643 against bovine viral diarrhoea virus and yellow fever virus, which were selected to serve as surrogates of hepatitis C virus, equalled or exceeded that of IFN-alpha (Namalwa). These results suggest that the genetically engineered YM643 is more potent than natural IFN-alpha.