Importance of pretreatment viral load and monitoring of serum hepatitis C virus RNA in predicting responses to interferon-alpha2a treatment of chronic hepatitis C. Hanshin Chronic Hepatitis C Study Group

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.

Effect of HCV viral dynamics on treatment design: lessons learned from HIV

Viral load measurements provide an indication of viral replication, and thereby serve as a valuable tool to guide the initiation of therapy and subsequent changes. Plasma human immunodeficiency viral load strongly predicts the rate of decrease in CD4+ lymphocyte count, and progression to AIDS and death. Furthermore, the efficacy of antiretroviral therapy can be assessed by monitoring changes in plasma human immunodeficiency viral load. Similarly, viral load provides valuable information about the natural history of the hepatitis C virus infection. Hepatitis C viral load can be used to predict the likelihood of response to standard interferon-alpha treatment and other interferon-alpha regimens and to monitor treatment efficacy. Increased understanding of the natural history of the hepatitis C virus infection and the nature of resistance to interferon-alpha therapy suggests that effective treatment regimens must maintain serum levels of interferon-alpha. Ideally, interferon-alpha serum levels should provide constant pressure on the virus and should prevent viral rebound, thereby avoiding continued viral replication and minimizing the potential for emergence of resistant quasi-species. Current regimens designed to address these points include early aggressive intervention, combination drug regimens, prolonged maintenance, and novel interferons. By enabling the design and rapid assessment of new treatment regimens, viral load measurement will revolutionize the clinical management of the hepatitis C virus infection, as it has the HIV.

Early predictors of response to treatment in patients with chronic hepatitis C

The term sustained response should be applied to patients with negative serum HCV-RNA and normal values of serum transaminases 6 months after interferon withdrawal. To investigate which factors identify sustained responders early during treatment we analysed 18 reports which used the definition sustained response. Eight reports, comprising 988 patients, have studied the value of early clearance of viraemia as a predictor of sustained response using multivariate analysis and all of them found that this was the strongest predictor of a sustained response. Determination of HCV-RNA 4 or 12 weeks after initiation of IFN therapy predicts treatment outcome more accurately than baseline viral load (the best pre-treatment predictor). ALT levels during the first 12 weeks of treatment have lower predictive value than early viral clearance. The sensitivity of a negative HCV-RNA test is similar at week 4 and at week 12 of therapy while the specificity and the accuracy is higher at week 4. The value of persistent viraemia for early prediction of no response is higher than 97%, with similar values at weeks 4 and 12. Persistence of HCV-RNA in serum at week 4 strongly indicates that the patient will not respond to treatment and in these cases interruption of treatment or other therapeutic options could be considered.

Correlation of interferon-induced expression of MxA mRNA in peripheral blood mononuclear cells with the response of patients with chronic active hepatitis C to IFN-alpha therapy

MxA, a protein with selective activity against certain viruses, is an accepted specific indicator of type I interferon (IFN) activity. We have developed an internally controlled quantitative-competitive PCR to measure the amounts of MxA mRNA expressed in peripheral blood mononuclear cells (PBMC). This assay is more sensitive, quantitative, and easily applied to serial clinical samples than previously described methods. We have applied this assay retrospectively to 27 patients with chronic active hepatitis C given IFN-alpha2. Most such patients gain no sustained benefit but nevertheless suffer from the side effects, expense, and inconvenience of the treatment. Fourteen of the 27 had been classified on clinical grounds as responders and 13 as nonresponders at the end of a 6 month treatment period. We measured MxA mRNA in PBMC obtained before and after 8 weeks of IFN-alpha2 treatment. All the patients expressed some level of mRNA before treatment began, and after 8 weeks of treatment, the level rose in 19. This increase was significant (p < 0.001) only in patients classified as responders. This strongly suggests that hepatitis C virus (HCV) patients who express increased amounts of MxA mRNA in their PBMC during IFN-alpha treatment are most likely to obtain long-term benefit. If this finding is confirmed in future prospective studies, it will provide an extremely important predictive marker for managing IFN-alpha therapy in patients with HCV.

Serum levels of thyroid-stimulating hormone receptor antibodies during IFN-alpha2a treatment of chronic hepatitis C

Twenty chronic hepatitis C patients with baseline levels of thyroid hormones, antithyroglobulin, and antimicrosomal antibodies within the normal range were monitored by thyroid testing during a 26-week treatment with interferon-alpha2a (IFN-alpha2a). The present study was aimed at retrospectively analyzing thyroid-stimulating hormone (TSH) receptor antibodies, employing stored serum samples obtained from these patients at baseline, at 12 weeks, and at the end of IFN-alpha2a treatment. Ten patients (group A) received IFN-alpha2a at a total dose of 474 million units (MU), and 10 patients (group B) at a total dose of 774 MU. None of the patients produced antithyroglobulin and antimicrosomal antibodies. Two patients in group A exhibited elevated TSH levels without free thyroid hormone alterations while on the treatment. At baseline, 1 patient in group A had a positive TSH binding inhibitory immunoglobulin, and 1 patient in group B was positive for thyroid-stimulating antibody at the end of treatment. Both patients remained euthyroid throughout the treatment. Treatment with IFN-alpha2a may infrequently induce the production of TSH receptor antibodies in chronic hepatitis C patients provided preexisting autoimmune thyroid disease is precluded.