Prediction of successful outcome in a randomised controlled trial of the long-term efficacy of interferon alpha treatment for chronic hepatitis C

Extended interferon-alpha therapy accelerates telomere length loss in human peripheral blood T lymphocytes

Background

Type I interferons have pleiotropic effects on host cells, including inhibiting telomerase in lymphocytes and antiviral activity. We tested the hypothesis that long-term interferon treatment would result in significant reduction in average telomere length in peripheral blood T lymphocytes.

Methods/Principal Findings

Using a flow cytometry-based telomere length assay on peripheral blood mononuclear cell samples from the Hepatitis-C Antiviral Long-term Treatment against Cirrhosis (HALT-C) study, we measured T cell telomere lengths at screening and at months 21 and 45 in 29 Hepatitis-C virus infected subjects. These subjects had failed to achieve a sustained virologic response following 24 weeks of pegylated-interferon-alpha plus ribavirin treatment and were subsequently randomized to either a no additional therapy group or a maintenance dose pegylated-IFNα group for an additional 3.5 years. Significant telomere loss in naïve T cells occurred in the first 21 months in the interferon-alpha group. Telomere losses were similar in both groups during the final two years. Expansion of CD8⁺CD45RA⁺CD57⁺ memory T cells and an inverse correlation of alanine aminotransferase levels with naïve CD8⁺ T cell telomere loss were observed in the control group but not in the interferon-alpha group. Telomere length at screening inversely correlated with Hepatitis-C viral load and body mass index.

Conclusions/Significance

Sustained interferon-alpha treatment increased telomere loss in naïve T cells, and inhibited the accumulation of T cell memory expansions. The durability of this effect and consequences for immune senescence need to be defined.

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.

Prediction of Efficacy of Interferon Treatment of Chronic Hepatitis C and Occurrence of HCC after Interferon Treatment by a New Classification

One hundred and twenty-one chronic hepatitis C patients were administered interferon (IFN) and divided into two groups: 31 complete responders (CR) with prolonged HCV-RNA negative 1 year after treatment and 90 non-complete responders (non-CR), including partial responders (PR) with transiently negative HCV-RNA and non-responders (NR) with continuously positive HCV-RNA. Liver biopsy specimens were classified into four grades and stages according to the degree of severity and the extent of fibrosis, respectively. No correlation was observed between the rate of IFN efficacy and grading. By staging, however, a difference in the efficacy of IFN was observed between F1 or F2 and F3 (0.05 < p < 0.1 and 0.01 < p < 0.025, respectively). Of the CR, 0% (0/5) were at F0 and 27.9% (24/86) at F1, 42.9% (6/14) at F2, and 6.3% (1/16) at F3. Another group of 118 chronic hepatitis patients (31 CR, 41 PR and 46 NR) followed up for over 2 years after IFN treatment were analyzed. By staging, 7 cases were at F0, 76 at F1, 18 at F2, and 17 at F3. HCC occurred in 1 of the 31 CR cases (representing an annual incidence rate of 1.21%), in 4 of the 41 PR cases (4.08%), and in 4 of the 46 NR cases (3.55%). HCC did not occur in any of the 7 cases at F0 (representing an annual incidence rate of 0%); it occurred in 2 of the 76 cases at F1 (1.01%), in 1 of the 18 cases at F2 (2.28%), and in 6 of the 17 cases at F3 (16.57%). These results suggest that the new classification would be conducive to roughly predicting the efficacy of IFN treatment and the occurrence of HCC after IFN treatment.

Characterization of the immune response against hepatitis C infection in recovered, and chronically infected chimpanzees

The immune response to hepatitis C virus (HCV) is believed to be critical in determining the outcome of the disease. In this study we have analysed epitope recognition, cytokine profile, and anti-HCV antibody responses in chronically HCV-infected and recovered chimpanzees. Quantitative measurement of anti-HCV antibody in HCV-infected chimpanzees revealed that the response in HCV- recovered chimpanzees peaked within 4-20 weeks. In contrast, the anti-HCV antibody responses in chronically HCV infected chimpanzees did not peak until 100-200 weeks after infection, and decreased gradually thereafter. T cell proliferation assays measuring responses to pooled HCV proteins revealed significant increases in the 3H-uptake during the early stages of infection in recovered chimpanzees in comparison to the chronically infected ones. Class I-restricted epitopes of the core, and NS3 proteins of HCV were analysed using 9-10 mer overlapping peptides covering the core and NS3 proteins, and IFN-gamma ELISPOT technique. Our data indicated early and broad class-I restricted core, and NS3 protein epitope recognitions in HCV-recovered chimpanzees but not in chimpanzees that had been chronically infected. Additionally, dominant epitopes recognized early in infection (8 weeks) were no longer recognized later in infection (followed up to 64 weeks). Cytokines profiling revealed a 50-fold increase in TNF-alpha secretion in the supernatant of core-specific CD8 memory cells of the chronically infected chimpanzees in comparison to the recovered ones. In summary, multiple parameters correlate with HCV recovery in chimpanzees.

African Americans with genotype 1 treated with interferon for chronic hepatitis C have a lower end of treatment response than Caucasians

African Americans as a group have a higher incidence of chronic hepatitis C (CHC) than Caucasians but are often under-represented in clinical trials used to define response rates to interferon therapy. The aim of this study was to compare African Americans with Caucasians with respect to end-of-treatment response to interferon. This retrospective study had 61 African Americans and 49 Caucasians with CHC. All patients were treated for at least 12 weeks with interferon-alpha2b (Intron A) thrice weekly. End-of-treatment response was defined as three consecutive nondetectable HCV RNA measurements at least 1 month apart. Sustained response was defined as a negative serum HCV RNA 6 months after end of treatment. Of the 110 patients, 19 achieved an end-of-treatment response (17%) but only four achieved a sustained response (4/110=4%). Of the patients achieving a sustained response, one was genotype 1 (male Caucasian), three were genotype 2/3 with four patients having no follow-up information. The end-of-treatment response was 7% for patients with genotype 1 and 71% for genotype non-1 (P < 0.005 for genotype non-1). The end-of-treatment response was significantly higher in Caucasians (14/49=31%) compared with African Americans (5/61=8%; P < 0.05). A lower response rate in African Americans with genotype 1 in contrast to Caucasians was the primary reason for the difference in end-of-treatment response (1/45=2% vs. 5/33=15%, P < 0.05). Hence, interferon treatment resulted in a poor sustained response rate in the group of patients representative of the urban populations with the highest prevalence of hepatitis C. A genotype other than type 1 was the strongest predictor of end-of-treatment response in patients treated but over 86% of patients in this urban clinic were genotype 1. Caucasians were more likely to respond than African Americans, especially in patients with genotype 1.

Relationship between five-year histological outcome and serial changes in serum alanine aminotransferase in patients with biochemical and virological relapse after interferon treatment for chronic hepatitis C

OBJECTIVE

The aim of this study was to assess the correlation between serial changes in serum alanine aminotransferase (ALT) levels and histological outcome 5 years after treatment of patients with chronic hepatitis C with interferon (IFN).

METHODS

We retrospectively evaluated 61 consecutive patients who underwent two liver biopsies, just before and 5 years after a 6-month course of IFN therapy, and who showed a relapse after therapy. The extent of liver fibrosis was estimated using a scale with seven grades.

RESULTS

At the end of 6-month IFN therapy, 40 (65.6%) patients had normal serum ALT concentrations. However, 13 of the 40 patients relapsed within 6 months after IFN therapy. The average ALT during 5 years in 40 patients was less than or equal to 75 IU/l, while in the other 21 patients it was more than 75 IU/l. Among the 40 patients with a mean ALT less than 75 IU/l, 13 (33%) patients showed histological improvement, 26 (65%) showed no changes and only 1 patient (2%) showed worsening of liver fibrosis. On the other hand, among the 21 patients with a mean ALT of more than 75 IU/l, only 1 (5%) patient showed improvement, 8 (38%) showed no changes and 12 patients (57%) showed worsening of liver fibrosis.

CONCLUSION

There is a significant relationship between 5-year histological outcome and serial changes in serum ALT in patients with biochemical and virological relapse after IFN treatment for chronic hepatitis C.

Hepatitis C virus and interferon resistance

Interferon plays a critical role in the host's natural defense against viral infections and in their treatment. It is the only therapy for hepatitis C virus (HCV) infection; however, many virus isolates are resistant. Several HCV proteins have been shown to possess properties that enable the virus to evade the interferon-mediated cellular antiviral responses.