Prediction of the response of chronic hepatitis C to interferon alfa: a statistical analysis of pretreatment variables

Chronic hepatitis C in patients with normal or near normal alanine aminotransferase levels: the role of interferon alpha 2b therapy

BACKGROUND/AIMS

Interferon is the only approved therapy for chronic hepatitis occurring as a consequence of an infection with the hepatitis C virus. Because interferon is expensive, has a large number of untoward effects and its efficacy is not guaranteed, many physicians limit their use of this therapy to those with histologically advanced but not end-stage cirrhotic disease. Moreover, most cases are biopsied only after 6 months or more of abnormal alanine aminotransferase levels have been documented. The rationale for this approach to patients with hepatitis C virus infection has not been demonstrated.

METHODS

In the present study, a total of 37 patients with alanine aminotransferase levels < 1.5 upper limits of normal (59 IU/l or less) who were HCV-RNA positive by reverse transcriptase polymerase chain reaction, were selected for interferon treatment, having been identified as having hepatitis C virus disease as the result of a screening Ab-HCV test confirmed with a positive radio immune blotting assay. Once identified, each subject underwent a percutaneous liver biopsy and was tested for the presence of HBsAg, Ab-HBs and HBV-DNA. All liver biopsies were read and graded according to the criteria of Knodell et al. Each subject was treated with interferon a2b at a dose of 5 MU administered daily until a response was achieved (a minimum period of 6 months) or until a full year had elapsed. A response was defined as HCV-RNA negativity in serum on three consecutive monthly determinations. The study population consisted of 21 males and 16 females ranging in age from 17 to 72 years (mean 46.7 +/- 2.2 years). Their mean serum alanine aminotransferase level at the initiation of therapy was 37.5 +/- 2.1 IU/l with a range of 10-59 (normal values being 40 IU/l or less). 54% of the subjects were presumed to have acquired their hepatitis C virus infection as a result of a blood transfusion; 32% as a result of prior intravenous drug abuse; and 13% had no identifiable risk factor for hepatitis C virus. Despite having normal or near normal serum alanine aminotransferase levels, 9 subjects had chronic persistent hepatitis, 13 had chronic active hepatitis and 15 had chronic active hepatitis + cirrhosis documented by histopathologic assessment of their liver biopsies.

RESULTS

An interferon response was achieved in 5/9 with chronic persistent hepatitis, 11/13 with chronic active hepatitis and 8/15 with chronic active hepatitis + cirrhosis for an overall response rate of 65%.

CONCLUSIONS

This study has demonstrated that individuals who: 1) are hepatitis C virus positive with serum alanine aminotransferase levels < 1.5 x upper limits of normal can have histologically advanced liver disease; 2) can respond to interferon therapy defined as clearance of detectable HCV-RNA in serum; and, 3) should be considered for interferon treatment.

Two dose regimens of recombinant interferon-alpha-2b in chronic hepatitis C virus infection. Biochemistry, hepatitis C virus RNA, and liver histology as response indices

BACKGROUND

Recombinant interferon remains the cornerstone of treatment of chronic hepatitis C virus (HCV) infection. Still, evaluation of treatment on the basis of response indicators and long-term effect of the treatment raises several questions.

METHODS

Seventy-four patients with chronic HCV infection were randomized to a high (3 MIU, 3/7 days) or low (1 MIU, 3/7 days) dose of recombinant interferon-alpha-2b for 48 weeks after a 4-week course of 3 MIU, 3/7 days. Response to treatment was assessed by means of liver enzymes (transaminases), HCV RNA, and liver histology.

RESULTS

The higher maintenance dose was associated with a significantly higher rate of sustained alanine aminotransferase (ALAT) response (45% versus 19%) and with a significantly better chance of becoming HCV RNA-negative during therapy (47% versus 23%). In the high maintenance dose group 14 of the 29 (48%) patients with available HCV RNA data were negative at the 3-month follow-up, compared with 4 of 27 (15%) in the low maintenance dose group. Significantly more patients had improved liver biopsy findings after interferon in the high maintenance dose group (79%) than in the low maintenance dose group (36%). There was a close correlation between ALAT response and HCV RNA response. Of 17 patients who were HCV RNA-negative 3 months after the end of treatment, 10 remained HCV RNA-negative 2-4 years later.

CONCLUSION

The study demonstrates a higher response rate as assessed by biochemistry, HCV RNA, and liver histology in the higher dose group.

Changes in blood lipid composition and response to interferon treatment in chronic hepatitis C

To assess whether the initial status of lipid metabolism in patients with chronic viral hepatitis might correlate with outcome of therapy, 52 patients (32 males and 20 female) with chronic hepatitis C were studied: 44 were treated with human recombinant interferon-alpha 2b (3 MU three times per week for up to 12 months), and 8 served as controls. At baseline, sera were tested for total and HDL cholesterol, HDL2, HDL3, apolipoprotein A-I, apolipoprotein B, interferon-alpha, tumor necrosis factor, and interleukin-6. Changes in blood lipids were evaluated after 3, 30, and 90 days of treatment. HDL cholesterol, apolipoprotein A-I, and HDL3 decreased by 9.4-11.4% within 4 weeks of starting interferon treatment, but this effect was sustained only in patients with a primary response to interferon. On multivariate analysis, a primary response to interferon correlated with higher apolipoprotein A-I and lower (< 2.23 pg/ml) interleukin-6 levels (p < 0.005 for both). In contrast, a sustained response was significantly more common in patients with low (< or = 13.3 pg/ml) serum interferon-alpha and lower interleukin-6 at baseline but did not correlate with any of the blood lipids. Thus, in chronic hepatitis C, interferon treatment induces specific changes in blood lipids. The concentration of apolipoprotein A-I at baseline is a strong predictor of primary response to treatment, and the likelihood of sustained response seems to be reflected by lower cytokine activation.

Host and viral features in chronic HCV infection: relevance to interferon responsiveness

Host and viral variables interact in determining the course and responsiveness to therapy of any viral infection. Presence of cirrhosis, serum levels of hepatitis C virus (HCV) RNA and the genotype of infecting virus are considered predictive of response to interferon (IFN) in chronic HCV infection. We evaluated these parameters in relation to IFN therapy in a cohort of anti-HCV-positive subjects with chronic hepatitis or cirrhosis. HCV RNA was detected by polymerase chain reaction (PCR) and by the branched DNA assay (bDNA), to quantify viraemia. HCV typing was performed by reverse-hybridization line probe assay. HCV RNA was detected in almost all anti-HCV-positive subjects with liver disease, PCR being more sensitive than bDNA. Hepatitis C viraemia was lowest in cirrhosis. Low pretreatment viraemia selected for those patients with chronic hepatitis obtaining a high rate of sustained response to IFN. The role of HCV type was less clearcut, due to the high prevalence in our population of type 1 (especially subtype 1b, accounting for 80% of cases). A trend towards a better response of non-1b genotypes was confirmed. This may be related to higher HCV RNA levels in type 1b-infected subjects. Cirrhosis remains however, independently from virological features, the strongest predictor of non-response to IFN.

Re-treatment of interferon-resistant patients with chronic hepatitis C with interferon-alpha

Non-responders to 6-months treatment with recombinant interferon (rIFN)-alpha, 3 MU thrice weekly (primary non-responders) were treated for 6 further months with the same therapy or with a double dose of rIFN-alpha or with a different type of IFN (L-IFN). 112 primary non-responders were randomly enrolled into four groups of 28 patients each over a period of 4 years and were followed up for 6 months: group A continued the same dose of rIFN-alpha, group B was treated with the same rIFN-alpha but received a double dose (6 MU thrice weekly), group C received L-IFN, 3 MU thrice weekly, and group D stopped IFN therapy and did not receive any treatment. Patients were examined at monthly intervals and response was defined as a complete normalization of alanine amino transferase (ALT). The four groups were homogeneous as to age, sex, duration of the disease, probable source of infection, histological diagnosis. ALT and gamma glutamyl transferase (gamma GT) levels. No patient discontinued therapy for side-effects. Further treatment with rIFN-alpha 3 MU thrice weekly (group A) induced normalization of ALT levels in four patients (14%); treatment with double-dosed rIFN-alpha (group B) induced normalization of liver enzymes in six cases (21%); a different type of interferon (L-IFN) (group C) achieved normalization of serum ALT in five patients (18%). None of 28 primary non-responders who did not receive any treatment (group D) showed normalization of ALT levels. None of the patients was anti-HCV negative at the end of the study and no statistically significant difference was noted between responders and non-responders to the second course of IFN therapy as to age, sex, duration of the disease. ALT and gamma GT levels at the end of the trial. Overall at the end of the study the primary non-responders with normal levels of ALT were 15/112 (13%), with a therapeutic advantage of 7%. No statistically significant difference in the response rate was found among patients who continued IFN therapy, but prolongation of rIFN-alpha treatment at double dosage seems to be the best therapeutic regimen.

Interferon therapy for patients more than 60 years of age with chronic hepatitis C

Nineteen patients aged > 60 years with chronic hepatitis C (CHC) received interferon (IFN) therapy and a complete response (CR) was achieved by five of them (26%). The incidence of CH with severe fibrosis in this elderly group was significantly higher than in another 52 patients with CHC who were < 60 years of age (the younger group; P < 0.05). There was no significant difference in the hepatitis C virus (HCV) genotype distribution between the elderly group and the younger group. However, the HCV-RNA titre was significantly higher in the elderly group than in the younger group (P < 0.05). There was no significant difference in the efficacy rate of IFN in the elderly and younger groups after standardization of the background factors. In the elderly group, the HCV-RNA titre was significantly lower in the patients achieving CR than in those with no response (P < 0.05). These data suggest that elderly patients with a low HCV-RNA titre can still respond well to IFN therapy.

Effect of cholestasis and bile acids on interferon-induced 2',5'-adenylate synthetase and NK cell activities

BACKGROUND/AIMS

The mechanisms involved in resistance to interferon alfa in patients with chronic hepatitis C are unclear. Both cirrhosis and cholestasis have been shown to be predictive of resistance. The aim of this study was to evaluate the influence of cholestasis and bile acids on 2',5'-oligoadenylate synthetase and natural killer activities, which are both involved in the antiviral activity of interferon.

METHODS

2',5'-Oligoadenylate synthetase activity was evaluated in spleen, liver, and isolated hepatocytes from bile duct-ligated rats, and the effect of bile acids in vitro on interferon-induced 2',5'-oligoadenylate synthetase and natural killer activities was examined in fresh mononuclear cells from healthy subjects.

RESULTS

Cholestasis had a time-dependent inhibitory effect on 2',5'-oligoadenylate synthetase activity in liver, spleen, and isolated hepatocytes from cholestatic rats (-70%, 86%, and 70% relative to baseline, respectively). In vitro, endogenous bile acids had a concentration-dependent inhibitory effect on interferon-induced 2',5'-oligoadenylate synthetase and natural killer activities, which was related to their structure. This inhibitory effect correlated with the surface activity index.

CONCLUSIONS

Cholestasis and bile acids diminish the biological activity of interferon and natural killer activity. The results suggest a decrease in the antiviral defenses in cholestatic conditions.

Hepatitis C: progress and problems

The hepatitis C virus (HCV), a single-stranded RNA virus, is the major cause of posttransfusion hepatitis. HCV isolates differ in nucleotide and amino acid sequences. Nucleotide changes are concentrated in hypervariable regions and may be related to immune selection. In most immunocompetent persons, HCV infection is diagnosed serologically, using antigens from conserved regions. Amplification of RNA may be necessary to detect infection in immunosuppressed patients. Transmission by known parenteral routes is frequent; other means of spread are less common and may represent inapparent, percutaneous dissemination. Infection can lead to classical acute hepatitis, but most infected persons have no history of acute disease. Once infected, most individuals apparently remain carriers of the virus, with varying degrees of hepatocyte damage and fibrosis ensuing. Chronic hepatitis may lead to cirrhosis and hepatocellular carcinoma. However, disease progression varies widely, from less than 2 years to cirrhosis in some patients to more than 30 years with only chronic hepatitis in others. Determinants important in deciding outcome are unknown. Alpha interferon, which results in sustained remission in selected patients, is the only available therapy. Long-term benefits from such therapy have not been demonstrated. Prevention of HCV infection by vaccination is likely to be challenging if ongoing viral mutation results in escape from neutralization and clearance.