Predictors of response to interferon therapy

Triple therapy with boceprevir for HCV genotype 1 infection: phase III results in relapsers and nonresponders

This is an excellent time for patients with hepatitis C virus infection who have failed past treatment with standard of care (SOC) peginterferon (PEG-IFN) and ribavirin (RBV). New treatments have been shown to increase sustained virological response (SVR) rates. Previous relapsers and those with some responsiveness to interferon will clearly benefit from protease inhibitor-based therapy. Patients with little interferon response may not be suited for these regimens, but can be treated by careful selection on a case-by-case basis. Resistance needs to be carefully monitored as these newer and more potent drugs are added to IFN and RBV backbone drugs. Adverse events will be more frequent and will require special attention.

Management of the treatment-experienced patient infected with hepatitis C virus genotype 1: options and considerations

Individuals infected with hepatitis C virus (HCV) are at risk for cirrhosis and/or hepatocellular carcinoma. Treatment of HCV infection has undergone several revisions over the past 15 years and continues to evolve. The current major advance is with the protease inhibitors in addition to pegylated interferon and ribavirin. The emergence of resistance needs to be monitored carefully as newer and more potent drugs are added to the interferon and ribavirin backbone drugs. In addition, adverse events will be more frequent and some novel ones will require special attention.

Epoetin alpha improves the response to antiviral treatment in HCV-related chronic hepatitis

BACKGROUND

The conventional antiviral treatment of chronic hepatitis related to hepatitis C virus (HCV) often leads to anemia. In this case, it is necessary to reduce ribavirin dose or stop treatment, thus reducing the rate of sustained virological response.

AIM

We investigated whether epoetin alpha administration improves treatment adherence and leads to higher percentage of response at the end of therapy and sustained virological response.

METHODS

Two hundred and fourteen individuals with genotype 1b HCV-related chronic hepatitis underwent treatment with pegylated (peg)-interferon alpha-2A 180 μg once weekly and ribavirin 1,000-1,200 mg/day; 174 were responders. Forty individuals completed treatment with no hemoglobin reduction; 134 developed anemia during therapy. Anemic responders were distributed randomly into two groups: group 1 continued therapy with epoetin alpha addiction; group 2 continued antiviral therapy with ribavirin reduction only.

RESULTS

Patients in group 1 achieved better control of hemoglobin levels (13.8 ± 1.2 g/dl at the end of therapy) than those in group 2 (11.5 ± 0.8 g/dl). Sustained virological response was 59.7% in group 1 compared with 34.4% in group 2 (p<0.01).

CONCLUSIONS

In patients with 1b HCV-related chronic hepatitis who develop anemia during antiviral treatment, administration of epoetin alpha increases hemoglobin levels and the end-of-treatment rate and sustains virological response by improving treatment adherence.

Consensus interferon and ribavirin in patients with chronic hepatitis C who were nonresponders to pegylated interferon alfa-2b and ribavirin

Recent studies suggest that consensus interferon and ribavirin is effective in retreating patients with chronic hepatitis C who failed therapy with interferon alfa and ribavirin. The objective of the present study was to assess the efficacy, safety, and tolerability of consensus interferon and ribavirin in patients who did not respond to pegylated interferon alfa-2b and ribavirin. We retrospectively identified 137 consecutive nonresponders to pegylated interferon alfa-2b and ribavirin and initiated patients on daily treatment with consensus interferon 15 mug subcutaneously and weight-based ribavirin for 48 weeks. If patients were HCV RNA negative at 12 weeks, the dose was reduced to 15 mug three times weekly for the remaining 36 weeks. The sustained virologic response rate was 37%. Daily consensus interferon therapy was safe and well tolerated in all patients. No dose reductions were required, and no patient discontinued therapy. Further studies of consensus interferon and ribavirin in nonresponders are warranted.

Consensus interferon for chronic hepatitis C patients with genotype 1 who failed to respond to, or relapsed after, interferon alpha-2b and ribavirin in combination: an Italian pilot study

OBJECTIVE

To evaluate the long-term efficacy of consensus interferon in the treatment of chronic hepatitis C patients with genotype 1 who failed to respond to, or relapsed after, combination therapy with interferon alpha-2b and ribavirin.

DESIGN

Open label pilot study.

METHODS

Twenty-four chronic hepatitis C outpatient non-responders to (12 cases), or relapsers after (12 cases), standard combination therapy were treated with consensus interferon (9 microg five times per week) for 36 weeks. The patients were followed up for a further 24 weeks. The primary end-point of the study was the rate of sustained virological response.

RESULTS

Sustained virological response was observed in 33% of previous non-responders and in 42% of previous relapsers. Improvement of the histological score was documented in 80% of previous non-responders and in all previous relapsers who showed undetectable levels of hepatitis C virus RNA at the end of treatment. Logistic regression analysis showed that sustained virological response was associated with a hepatitis C viral load of 2 x 106 copies/ml or less, with an inflammation score of 7 or less and with an estimated duration of disease of 10 years or less. The treatment was well tolerated with an 83% compliance.

CONCLUSIONS

Consensus interferon given at a dose of 9 microg five times per week for 36 weeks may offer a good chance of sustained virological response in a subset of patients who failed to respond to, or relapsed after, standard combination therapy. However, a larger randomized trial is required to assess the efficacy of consensus interferon before its use can be advocated for the treatment of such patients.

Susceptibility testing. Viral pathogens

The control of the global expansion and proliferation of the AIDS pandemic has been complicated by the emergence of resistant strains of HIV-1 to the many new antiviral drugs directed to the genes coding for reverse transcriptase and protease enzymes of the virus. Similarly, new drug regimens for the management of chronic hepatitis B and C infections have been complicated by the lack of sustained clinical responses recently associated with either nucleotide mutation (HBV) or specific genotype of the virus (HCV). Commercial systems for performing and interpreting genotypic analysis will facilitate the recognition of informative mutations, standardize results between laboratories, and produce informative and interpretative result formats for optimal treatment of patients. Drug-resistant strains of herpesviruses (HSV, VZV, CMV) are generally associated with prolonged treatment of these infections in immunocompromised patients. Ultimate relevance of genotypic assays for routine clinical practice will require correlation with phenotypic results and the outcomes of long-term studies associating clinical improvement with antiviral drugs with specific mutation patterns of these viruses.

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.

Evaluation of long-term efficacy of interferon alpha-2b and ribavirin in combination in naive patients with chronic hepatitis C: an Italian multicenter experience. Ribavirin-Interferon in Chronic Hepatitis Italian Group Investigators

BACKGROUND/AIMS

A combination of interferon alpha and ribavirin has been suggested to reach a higher rate of sustained virological response in patients with chronic hepatitis C than monotherapy. In this study we assessed the long-term efficacy of this combination therapy in the treatment of selected Italian naive chronic hepatitis C patients compared to interferon alpha monotherapy.

METHODS

We enrolled 428 naive patients who were randomly assigned to receive either recombinant interferon alpha-2b and ribavirin for 24 weeks or interferon alpha-2b alone for 48 weeks. The primary end-point of the study was the rate of sustained virological response. Serum HCV RNA levels were determined before treatment; during treatment at weeks 12 and 24 in the patients receiving the combination therapy; at weeks 12, 24, 36 and 48 in the patients receiving monotherapy; and after therapy at weeks 12, 24 and 48 in the patients in both study groups.

RESULTS

Sustained virological response was observed in 43% of the patients treated with combination therapy and in 14% of the patients treated with monotherapy. Logistic regression analysis showed that sustained response was associated with the combination therapy, with HCV genotype other than 1b, with an HCV viral load of 3x10(6) copies/ml or less, with an inflammation score of 7 or less, and with an estimated duration of disease of 10 years or less.

CONCLUSIONS

A 24-week treatment course with interferon alpha-2b and ribavirin offers a greater chance of sustained virological response compared to treatment with interferon alpha-2b alone for 48 weeks, and may be indicated as initial therapy in such patients.

Genetic changes in the interferon sensitivity determining region of hepatitis C virus during the natural course of chronic hepatitis C

Amino acid mutations in the interferon sensitivity determining region (ISDR) are closely associated with the response to interferon in patients with hepatitis C virus genotype 1b (HCV-1b) infection. In this study, 36 patients chronically infected with HCV-1b, with no history of interferon therapy with respect to ISDR changes in HCV were studied. Two serum samples were obtained from each patient, with an average interval of 3.5 years, and predominant nucleotide and amino acid sequences of the ISDR at initial and subsequent time points were compared for each patient. Three of 12 patients with the wild type ISDR (no amino acid mutation in the ISDR compared to the consensus sequence) changed to the intermediate type (1 to 3 mutations) at later time points, whereas the other 9 still had the wild type. Similarly, 2 of 18 patients with the intermediate type changed to the wild type, whereas the other 16 patients continued to have the intermediate type. One of 6 patients with the mutant type (4 or more mutations) changed to the intermediate type, and the other 5 continued to have the mutant type. Although ISDR nucleotide changes/site/year were not significantly different among the 3 groups of patients, percentages of non-synonymous nucleotide changes were greater in the mutant type (63%) than the wild (9%) or the intermediate type (20%) (P < 0.05). These results show that mutations in the ISDR do not occur frequently, suggesting that interferon sensitivity does not change greatly during the natural course of the disease in each patient.

Hepatitis C virus infection: Review and implications for the dentist

OBJECTIVE

The purpose of this report was to review the current literature on hepatitis C virus infection, with particular attention to the aspects of interest for dental health care staff.

MATERIAL AND METHODS

The authors searched original research and review articles on specific aspects of hepatitis C virus infection, including articles on virology, epidemiology, transmission, diagnosis, natural history, extrahepatic manifestations, therapy and oral aspects of hepatitis C virus infection. The relevant material was evaluated and reviewed.

RESULTS

Hepatitis C virus is an RNA virus that is present throughout the world and has major geographic variations. The virus, transmitted mainly by means of blood contact, causes chronic hepatitis in up to 80% of cases and may give rise to hepatic cirrhosis and hepatocellular carcinoma in a significant proportion of patients. Although it is of limited efficacy, interferon alpha is currently the drug of choice in the treatment of the infection. Hepatitis C virus infection is associated with a number of extrahepatic manifestations that may include oral diseases such as lichen planus or sialadenitis. Although there are documented cases of nosocomial transmission to health care workers after percutaneous exposure, the prevalence of hepatitis C virus among dental staff members is probably similar to that in the general population.

CONCLUSION

Hepatitis C virus infection is a relatively common infection worldwide (1.4% in the US general population) that causes significant chronic hepatic disease. The dentist is thus likely to face a growing number of patients with a diagnosis of hepatitis C virus infection. For this reason it is essential for dental health care workers to be aware of the principal features of the disease and of its oral and dental implications.

Review article: interferon and hepatitis C--factors predicting therapeutic outcome

Hepatitis C chronically infects approximately 1.5% of Americans and is the most common clinical problem facing hepatologists. Since the virus was initially described in 1989, development of an effective therapy has been challenging. Although several different therapeutic agents have been used, no therapy has been shown to reliably eradicate the virus. Interferon-alpha, a cytokine with immunostimulatory and anti-viral properties, has become the therapy of choice for patients with chronic hepatitis C infection. Trials assessing the efficacy of interferon-alpha have characterized host and viral factors predictive of responses to treatment. A thorough understanding of these predictive factors is requisite to providing cost-effective therapeutic decisions for the patient with chronic hepatitis C infection.