Treatment of chronic hepatitis C with interferon-alpha by monitoring the response according to viraemia

Peginterferon-alfa2a plus ribavirin for 48 versus 72 weeks in patients with detectable hepatitis C virus RNA at week 4 of treatment

BACKGROUND & AIMS

Patients with chronic hepatitis C who do not respond rapidly to therapy have a low chance of developing a sustained virologic response (SVR) when treated for 48 weeks. This study investigated whether treatment for 72 weeks increases the rate of SVR in patients with detectable hepatitis C virus (HCV)-RNA levels at week 4 of treatment.

METHODS

A total of 510 treatment-naive patients were treated with peginterferon-alfa2a (180 microg/wk) plus ribavirin (800 mg/day). Patients with detectable HCV-RNA levels at week 4 (n = 326) were randomized to complete 48 (group A, n = 165) or 72 weeks (group B, n = 161) of treatment. Patients with undetectable HCV-RNA levels at week 4 (n = 184) were allocated into group C (n = 148) or group D (n = 36), according to HCV genotype and baseline viremia, and treated for 24 or 48 weeks, respectively. All patients were followed-up for 24 weeks after the end of treatment.

RESULTS

The end-of-treatment response rate (61%) was similar in groups A and B, but the SVR rate was higher in group B (45% vs 32% in A; P = .01). In genotype 1-infected patients randomized to group A (n = 149) or B (n = 142), SVR rates were 28% and 44%, respectively (P = .003). The incidence of adverse events was similar in all groups. Treatment discontinuation was more frequent in group B (36%) than in group A (18%) (P = .0004). SVR rates in groups C and D were 79% and 64%, respectively.

CONCLUSIONS

Extension of treatment with peginterferon-alfa2a plus ribavirin from 48 to 72 weeks significantly increases the rate of SVR in patients with detectable viremia at week 4 of treatment.

Is delayed normalization of alanine aminotransferase a poor prognostic predictor in chronic hepatitis C patients treated with a combined interferon and ribavirin therapy?

BACKGROUND AND AIMS

Decreased alanine aminotransferase (ALT) level is the accepted basic indicator of an interferon (IFN) therapeutic effect in chronic hepatitis C. This study assessed whether delayed normalization of ALT predicts a poor response to a combined therapy of IFN and ribavirin in patients with chronic hepatitis C virus (HCV) infection.

METHODS

Patients were treated with IFN-alpha 2b three times weekly and oral ribavirin for 24 weeks. The ALT values were assessed monthly and patterns of changes in ALT activity were analyzed. Serum HCV-RNA was checked at weeks 0, 12, 24, and 48.

RESULTS

A total of 103 patients completed therapy and 69 (67%) of them achieved a sustained viral response (SVR). There was no significant difference in the SVR between patients with or without early normalization (week 12) of ALT level (69 vs 56%). Of the sustained responders, nine patients (13%) with delayed ALT normalization had a SVR. Nine of the 12 patients (75%) with abnormal ALT and negative HCV-RNA at week 12 had a SVR compared with none of four patients who had positive HCV-RNA at week 12 (P = 0.0192).

CONCLUSIONS

Lack of normalization of the ALT level at week 12 does not preclude successful virological outcome in hepatitis C patients receiving a combined therapy of IFN and ribavirin. Hepatitis C virus RNA at week 12 may be a useful predictor of treatment outcome in patients without early biochemical response.

Improved version 2.0 qualitative and quantitative AMPLICOR reverse transcription-PCR tests for hepatitis C virus RNA: calibration to international units, enhanced genotype reactivity, and performance characteristics

Version 2.0 qualitative and quantitative AMPLICOR reverse transcription-PCR tests for HCV were designed to improve on the performance of first version of the hepatitis C virus (HCV) tests. The new tests were calibrated in international units, the new commonly accepted standard unit of measurement for HCV RNA. The sensitivity of the qualitative tests was enhanced by modifying the specimen processing procedure to achieve a limit of detection 50 IU/ml. The limit of detection for the quantitative tests was 600 IU/ml. Modifications to the amplification reaction mixture and thermal cycling conditions enabled all genotypes to be amplified with similar efficiency. The quantitative tests exhibited a linear range extending from 500 to 500,000 IU/ml and excellent reproducibility, with coefficients of variation ranging from 18 to 39%, within the linear range. These data indicate that the version 2. 0 AMPLICOR HCV tests will improve diagnosis of HCV infection and will yield more-accurate titers for prognosis and for monitoring therapeutic efficacy, particularly at low viral loads. Furthermore, it will be possible to compare the performance characteristics and viral load measurements of AMPLICOR tests to those of other tests that adopt the international unit as the standard of measurement.

Performance characteristics of a quantitative, homogeneous TaqMan RT-PCR test for HCV RNA

We developed a homogeneous format reverse transcription-polymerase chain reaction assay for quantitating hepatitis C virus (HCV) RNA based on the TaqMan principle, in which signal is generated by cleaving a target-specific probe during amplification. The test uses two probes, one specific for HCV and one specific for an internal control, containing fluorophores with different emission spectra. Titers are calculated in international units (IU)/ml by comparing the HCV signal generated by test samples to that generated by a set of external standards. Endpoint titration experiments demonstrated that samples containing 28 IU/ml give positive results 95% of the time. Based on these data, the limit of detection was set conservatively at 40 IU/ml. All HCV genotypes were amplified with equal efficiency and accurately quantitated: when equal quantities of RNA were tested, each genotype produced virtually identical fluorescent signals. The test exhibited a linear range extending from 64 to 4,180,000 IU/ml and excellent reproducibility, with coefficients of variation ranging from 21.6 to 30.4%, which implies that titers that differ by a factor of twofold (0.3 log10) are statistically significant (P = 0.005). The test did not react with other organisms likely to co-infect patients with hepatitis C and exhibited a specificity of 99% when evaluated on a set of samples from HCV seronegative blood donors. In interferon-treated patients, the patterns of viral load changes revealed by the TaqMan HCV quantitative test distinguished responders from nonresponders and responder-relapsers. These data indicate that the TaqMan quantitative HCV test provides an attractive alternative for measuring HCV viral load and should prove useful for prognosis and for monitoring the efficacy of antiviral treatments.

Utility of early testing for HCV viremia as predictive factor of sustained response during interferon or interferon plus ribavirin treatment

BACKGROUND/AIM

To evaluate the utility of early testing for hepatitis C viremia as a predictor of treatment outcome during interferon or combination therapy.

METHODS

We studied 184 patients with chronic hepatitis C who received interferon and were monitored for HCV RNA. Sixty-two patients received interferon alone for 12 months and 122 patients, who were still HCV RNA positive at 2 months, received an additional 12-month course of interferon and ribavirin combination therapy.

RESULTS

Using this strategy, sustained response occurred in a total of 34 patients (18.5%). Independent variables associated with sustained response were HCV genotype (p=0.06), viral load < or = 5.1 logs/ml (p= 0.005) and negative HCV RNA at 1 month (p<0.0001) in the interferon group, and female sex (p=0.04), genotype (p=0.03), viral load < or = 5.5 logs/ml (p=0.01), normal ALT (p=0.001) and decline in viral load > or = 1.2 logs/ml after 2 months of interferon monotherapy (p<0.001) and negative viremia at 5 months of ribavirin onset (p<0.0001) in the combination therapy group. Persistence of viremia at 1 month of interferon monotherapy and at 5 months of combination therapy were the strongest predictors of non-response (negative predictive value of 100% and 99%, respectively).

CONCLUSIONS

Qualitative assessment of HCV RNA during treatment is the strongest predictor of sustained response during interferon or combination therapy for chronic hepatitis C.

Methodological issues in papers on IFN therapy: time for reappraisal

We conducted an analytical review of 194 full papers on interferon (IFN) therapy for chronic hepatitis C to evaluate current methodology (i.e. study design, criteria for evaluating the efficacy of therapy and predictors of response). Of the papers evaluated, 64 were randomized controlled trials (RCT), 40 were non-randomized controlled trials (NRCT) and 90 were observational studies (OS). The methodological analysis was focused mainly on clinical trials. The number of patients enrolled in RCT was higher compared with the number enrolled in NRCT. Uniform enrolment criteria were used in less than 50% of the trials. Only 20% of RCT and 2.5% of NRCT used criteria for defining sample size. The response rate was calculated on an intention-to-treat basis in 36 of the RCT and in 14 of the NRCT. The outcome of treatment and the criteria employed to define the response to treatment were found to be far from standardized. In 51.5% of the RCT and 42.5% of the NRCT, normalization of alanine aminotransferase (ALT) level at the end of follow-up was the only marker of response studied. Only 57.6% of the trials considered histological evidence as an important outcome. Among the clinical trials, 71.1% evaluated predictors of good response to IFN therapy. In 51% of the OS, ALT normalization by the end of follow-up was the only criterion for defining response. In conclusion, to ensure a high level of reliability in comparing or combining the results of different studies, some basic general requirements must be followed when planning trials on antiviral therapy.