Treatment of chronic hepatitis C

Telaprevir/boceprevir era: From bench to bed and back

Hepatitis C virus (HCV) infects approximately 200 million people worldwide. Interferon-based therapies have dominated over the past two decades. However, the overall response rates remain suboptimal. Thanks to the tremendous effort from both academia and industry, two serine protease inhibitors telaprevir and boceprevir for treating chronic hepatitis C have finally reached the clinic. Although these compounds are only approved for combination use with interferon and ribavirin in genotype 1 HCV infected chronic patients, the management of HCV patients however is now evolving incredibly. Here, we overviewed a series of landmark studies, regarding the clinical development of telaprevir and boceprevir. We discussed the mechanism-of-action of telaprevir/boceprevir and their potential application in HCV-positive liver transplantation patients. We further emphasized some emerging concerns with perspective of further development in this field.

Preliminary report of a randomized, double-blind placebo-controlled trial of a Chinese herbal medicine preparation CH-100 in the treatment of chronic hepatitis C

The treatment of chronic hepatitis C is relatively unsatisfactory and many patients have turned to unproven alternative medicines to modify the course of their illness. We report a study of a Chinese herbal medicine preparation CH-100 in the management of chronic hepatitis C. Patients with documented chronic hepatitis C were randomly allocated to receive active herbal or placebo tablets (five tablets thrice daily). Patients were followed monthly and evaluated by a Western and a traditional Chinese medical practitioner. Therapy was monitored by measurement of liver function tests, creatinine and full blood count on a monthly basis. Twenty patients in each group were well matched for age, sex, duration of illness, previous interferon therapy and alcohol intake. Active Chinese herbal medication was associated with a significant reduction in alanine aminotransferase (ALT) levels over the 6 month study period (P < 0.03). No patient cleared the virus but four normalized their ALT on treatment. Appropriately prescribed Chinese herbal medicine may have a role in the management of chronic hepatitis C and further controlled studies are indicated.

Quasispecies nature of hepatitis C virus and response to alpha interferon: significance as a predictor of direct response to interferon

BACKGROUND/AIMS

We evaluated the significance of the quasispecies nature of HCV as a predictor of the response to alpha interferon therapy in patients with chronic hepatitis C.

METHODS

Natural alpha interferon was administered in 62 patients for 24 weeks (daily for 2 weeks, then three times weekly for 22 weeks) and factors were analyzed that could affect the response. HCV subtype, HCV RNA concentrations and the number of HCV quasispecies were evaluated before treatment. HCV RNA concentrations were measured by branched DNA probe assay. The number of HCV quasispecies was measured by fluorescence single-strand conformation polymorphism analysis.

RESULTS

The HCV RNA concentration (p < 0.0001), HCV subtype (p = 0.0076), and the number of HCV quasispecies (p = 0.0024) were significantly associated with a complete response. Multivariate analyses showed that the number of HCV quasispecies was an independent predictor of the disappearance of HCV RNA during the administration of alpha interferon, but did not predict a relapse after its completion. Pretreatment concentration of HCV RNA was the only factor that was related to a long-term disappearance of HCV RNA.

CONCLUSIONS

The number of HCV quasispecies was significantly related to the response to alpha interferon early in its administration. The pretreatment concentration of HCV RNA was mainly related to a relapse following completion of treatment.

Virus and host factors are both important determinants of response to interferon treatment among patients with chronic hepatitis C

Virus and host factors have both been linked to the response to interferon treatment among patients with chronic hepatitis C but their relative importance and potential interactions are unclear. Hepatitis C virus genotype and level of viraemia were determined in pretreatment sera from 65 Australian patients treated with interferon-alpha 2b (IFN-alpha 2b), 3 MU tiw for 6 months. Hepatitis C viraemia was quantitated by a competitive reverse transcription-polymerase chain reaction (RT-PCR) method and genotype was determined by a line probe assay. By univariate analysis, there were positive associations between initial (short-term) responses to IFN treatment and younger age (P = 0.004), absence of cirrhosis (P = 0.01), and injecting drug use as risk factor for infection (P = 0.05) but not gender, duration of infection, or level of viraemia. Genotype appeared to be important (P = 0.06) but failed to reach statistical significance. By multivariate analysis, absence of cirrhosis was the only significant independent predictor of treatment response (P = 0.01). Among initial responders, the factors associated with long-term response were the pretreatment HCV RNA titre and the duration of infection. There was a close association between viral genotype, but not viral load, and the severity of liver disease. An interplay of factors determines the outcome of a 6-month course of interferon treatment for hepatitis C. Severity of liver disease, but not the viral load, is the most crucial determinant of initial response to interferon, and histological severity appeared to be influenced by the viral genotype. The level of hepatitis C virus (HCV) viraemia and the duration of infection are independent determinants of long-term response by affecting the relapse rate after interferon treatment.

Interferon alfa-2b for chronic hepatitis C: effects of dose increment and duration of treatment on response rates. Results of the first multicentre Australian trial. Australia Hepatitis C Study Group

Two hundred and thirty patients with histologically proven chronic hepatitis C were randomized to receive one of the following treatment protocols: (a) 3 million units of interferon alfa-2b thrice weekly for 6 months, (b) 5 million units thrice weekly for 6 months, or (c) 3 million units thrice weekly for 2 years. The short-term response to treatment was defined by normal alanine aminotransferase for at least 3 months and until the end of treatment, and was confirmed by loss of hepatitis C viraemia in 42 (91%) of 46 cases as determined by reverse transcription-polymerase chain reaction. Short-term response to interferon alfa-2b was independent of the incremental dose, being 64% for 5 million units and 58% for 3 million units. Long-term response to interferon alfa-2b was defined by continued normality of alanine aminotransferase levels for at least 6 months after treatment withdrawal. The long-term response rates among responders treated for 6 months and those treated for 2 years were 29% and 54%, respectively (p < 0.001). Among all 18 patients tested, serum HCV-RNA was negative at both 6 and 12 months of follow-up in all long-term responders, and none have subsequently relapsed. Improvement in hepatic necroinflammatory changes was confirmed by quantitative histology (Scheuer score) in responders at the end of interferon alfa-2b treatment. The changes were significantly greater among those who had been treated for 2 years compared with those treated for 6 months (p < 0.05 and p < 0.02, respectively, for portal and lobular inflammation scores). Several pretreatment characteristics could be correlated with a favourable response to interferon alfa-2b. Thus, absence of cirrhosis was associated with a short-term response of 75%, while only 42% of patients with cirrhosis had a short-term response (p < 0.001). The frequency of short-term response to interferon alfa-2b also differed according to mode of disease acquisition, being best for injecting drug use (71%), less favourable for blood transfusion (56%) and worst for sporadic cases (43%) (p < 0.01). This observed difference, however, was not independent of histology on multivariate analysis. In summary, a 5 million unit dose of interferon alfa-2b failed to improve the short-term or long-term response to interferon alfa-2b treatment, but prolongation of interferon alfa-2b treatment to 2 years resulted in substantially improved long-term response rate.

Treatment of chronic hepatitis C with interferon-alpha: sustained absence of hepatitis C virus RNA from serum after four courses of therapy

A patient with chronic hepatitis type C, confirmed by the detection of hepatitis C virus RNA (HCV RNA) in the serum and by histological examination of the liver biopsy specimen, was treated with four courses of interferon-alpha (IFN-alpha). For the first three courses of IFN-alpha the patient's serum alanine aminotransferase (ALT) level normalized during the administration of IFN-alpha but rose again after its cessation; similarly, HCV RNA was absent from the serum by the end of each course of treatment but could be detected once again after treatment stopped. The fourth course of IFN-alpha therapy, however, produced a sustained normalization of the ALT level and sustained absence of HCV RNA from the serum for 20 months after the end of treatment. This case suggests that patients with the potential for an eventual complete response to IFN-alpha therapy may show a normalization of serum ALT levels during IFN-alpha administration and the absence of HCV RNA in the serum by the end of each course of treatment (even if that particular course of treatment does not produce a sustained response).

Intrahepatic mononuclear cell populations and MHC antigen expression in patients with chronic hepatitis C [correction of B]: effect of interferon-alpha

Twenty-four subjects with chronic HCV infection were treated with IFN for six months. Liver biopsies were obtained before and after therapy. The number of mononuclear cells staining for CD3, CD4, CD8, 3G8, and the number of mononuclear cells, liver cells, and bile duct cells staining for class I and II MHC antigens in the biopsies was determined. NK cells increased from 16 +/- 3 to 28 +/- 3 cells per 5 high-power fields (HFP) (P < or = 0.03). The number of bile duct cells expressing class I and II MHC Ag and liver cells expressing class II MHC Ag increased (all P < or = 0.03). The only parameter that distinguished responders from nonresponders was the number of NK cells. Following IFN withdrawal, expression of these antigens declined. Based upon these data, it is concluded that IFN treatment of HCV increases: (1) the NK cells number; (2) the expression of class I MHC Ag on bile duct cells and the expression of class II MHC Ag on liver and bile duct cells; and (3) with IFN withdrawal, these changes disappear.

Neutralizing antibodies to recombinant alpha-interferon and response to therapy in chronic hepatitis C virus infection

Forty-seven patients with chronic hepatitis C were treated with recombinant interferon alpha-2a (rIFN alpha 2a) given subcutaneously in a standard dose of 3 MU thrice weekly for 12 months. Stored baseline sera and monthly samples during treatment were assayed for anti-interferon neutralizing antibodies using the antiviral neutralization bioassay against 5 IU of rIFN alpha 2a. During therapy, 15 of 47 patients (31.9%) developed detectable levels of neutralizing antibodies within 2-8 months after starting treatment. After 12 months of therapy, 26 of 32 antibody-negative patients (81.3%) showed normalization or marked reduction of ALT levels compared to 4 of 15 (26.6%) who developed anti-IFN neutralizing antibodies (p = 0.0009). Four patients demonstrated antiviral response during treatment even in the presence of low levels or late occurrence of neutralizing antibodies. Six of the seven patients who had disease reactivation after an initial response developed high titers of neutralizing antibodies. Our results suggest that reactivation of chronic hepatitis C before completion of therapy seems to be an obvious consequence of anti-IFN neutralizing antibody formation.

High prevalence of antibodies to hepatitis C virus among family members of patients with anti-HCV-positive chronic liver disease

We have evaluated the intrafamilial transmission of hepatitis C virus (HCV) by studying 1) the 107 household contacts of 43 patients with chronic HCV liver disease, 2) the household contacts of 30 anti-HCV-positive donors without liver disease, and 3) 3108 blood donors. We also studied the possible manner of the intrafamilial transmission. The prevalence of anti-HCV positivity in the families of index patients was significantly higher than in donors (14.9% as against to 1.7%). All the family members of the anti-HCV-positive donors were anti-HCV negative. We conclude that the person-to-person transmission of HCV is possible and most probable in contacts of anti-HCV-positive patients with liver disease.

2',5'-Oligoadenylate synthetase activity as a responsive marker during interferon therapy for chronic hepatitis C

The 2',5'-oligoadenylate (2-5A) synthetase is an intracellular enzyme induced by interferon (IFN). We evaluated the serum level of this enzyme in 25 patients affected by chronic hepatitis C and treated with recombinant IFN-alpha 2b. At the end of treatment, 14 patients were classified as responders and 11 as nonresponders. Before therapy initiation no significant differences in 2-5A synthetase levels among the patients were detected, while during therapy responders showed higher mean levels of 2-5A synthetase than nonresponders. An increase in the enzyme activity was observed after 1 month of therapy, and this trend was maintained in the following 2 months. The peak of 2-5A synthetase activity was found at the end of therapy. 2-5A synthetase levels were negatively correlated with serum alanine aminotransferase (ALT). This study suggests that 2-5A synthetase may be a useful marker to monitor IFN efficacy during treatment and to predict the clinical response.