Re-treatment of chronic hepatitis C with consensus interferon

Treatment of chronic hepatitis C: impact of combination therapy

Interferon as a single agent results in normalization of the serum alanine aminotransferase (ALT) levels, loss of detectable serum hepatitis C virus RNA, and histologic improvement in approximately 40% of patients. However, regardless of the duration of initial therapy, most patients relapse within the first few months after the drug is stopped, and only a small proportion have a sustained response. Ribavirin is a nucleoside analogue that is known to have in vitro activity against a number of both RNA and DNA viruses. As a single agent, oral ribavirin treatment transiently lowers serum ALT values into the normal range in about 40% of cases of chronic hepatitis C, but it does not affect the level of viremia. However, when given in combination with interferon for 6 to 12 months, ribavirin results in a sustained normalization of serum ALT levels and loss of detectable hepatitis C virus RNA in 30% to 40% of previously untreated patients. Retreatment of interferon relapsers with the combination of interferon and oral ribavirin for 6 months results in a sustained viral-negative response in about half of patients. Thus far, there is little evidence that combination therapy is effective in patients in whom ALT fails to normalize and who have lost hepatitis C virus RNA during a previous treatment course (nonresponders). Studies are ongoing in this group.

Advances in antiviral therapy

Multiple agents for the treatment and prevention of viral illnesses have been developed during the past few years. While in many cases this has been in direct response to the human immunodeficiency virus type 1 epidemic, a number of new antiviral agents are relevant to the practice of general pediatrics. This article reviews recent advances in the therapy of some common and a few unusual viral illnesses of children. The indication and efficacy of the newly developed agents valacyclovir, famciclovir, cidofovir, oral and intraocular ganciclovir, adefovir, respiratory syncytial virus immune globulin, palivizumab, and imiquimod are discussed, as well new uses of acyclovir, lamivudine, and ribavirin. Many of the antivirals discussed, including valacyclovir and cidofovir, have not yet been studied in children, but they hold promise for improving the treatment of pediatric viral infections.

Better efficacy of a 12-month interferon alfa-2b retreatment in patients with chronic hepatitis C relapsing after a 6-month treatment: a multicenter, controlled, randomized trial. Le Groupe D'étude et De Traitement du Virus De L'hépatite C (Get.Vhc)

We studied the efficacy of three interferon alfa-2b (IFN-2b) regimens for the retreatment of patients with chronic hepatitis C (CHC) with prior complete response followed by relapse. Consecutive patients with CHC who had a complete biochemical response but relapse after a first course of 6 months of IFN with 3 million units (MU) given subcutaneously three times per week were enrolled in the study. Six to 24 months after the end of the first treatment, the patients were randomly assigned to receive IFN with either the same regimen (group 1), a regimen of 12 months with 3 MU (group 2), or a regimen of 6 months with 10 MU (group 3). Sustained biochemical response was defined as normal serum alanine transaminase (ALT) values during the follow-up and sustained virological response as a clearance of hepatitis C virus (HCV) RNA from the serum at the end of follow-up (6 months' posttreatment). Histological improvement was defined as a decrease of 1 point in Metavir score between the first liver biopsy and a biopsy performed at 6 months' postretreatment. Two hundred forty-seven patients were randomized: 75 to group 1, 91 to group 2, and 81 to group 3. In an intent-to-treat analysis, 12%, 36.3%, and 18.5% of patients had a sustained biochemical response after retreatment in groups 1, 2, and 3, respectively (P <.001); 13. 8%, 32.4%, and 17.2% of patients had a sustained virological response after retreatment in groups 1, 2, and 3, respectively (P <. 05). A low viral load and patients in group 2 were independently associated with a sustained biochemical response. A low Knodell score index before treatment, patients with a high level of ALT before retreatment, genotype 3, low viral load, and patients in group 2 were independently associated with sustained virological response. Younger age, a high level of ALT, a low level of gamma-glutamyl transferase before retreatment, low viral load, and patients in group 2 were independently associated with sustained biochemical and virological response. Among the 80 patients with repeated liver biopsies, 47.6% had improved histological activity scores; this improvement was associated with a sustained biochemical and virological response. In patients with CHC initially treated with 3 MU of IFN given subcutaneously three times per week over a 6-month period, and who subsequently developed a relapse after a biochemical response, retreatment with a regimen of 3 MU of IFN given three times per week for 12 months produced better biochemical and virological sustained response rates than regimens involving a higher dose or a shorter duration of retreatment. The biochemical and virological sustained response was associated with histological improvement.

Early hepatitis C virus-RNA responses predict interferon treatment outcomes in chronic hepatitis C. The Consensus Interferon Study Group

In previous studies employing interferons (IFNs) in the treatment of chronic hepatitis C, there have been few reliable predictors of sustained responses. We retrospectively evaluated the predictive value of hepatitis C virus (HCV)-RNA measurements in the first few months during consensus interferon (CIFN) treatment using a sensitive reverse-transcriptase polymerase chain reaction assay to determine sustained responses. Data from two large treatment trials, one of IFN-naive patients and one of retreated relapsers and nonresponders, were used, including serum samples at 2-week intervals in the naive study and 8-week intervals in the retreatment study. Patients received initial CIFN (9 microgram) treatment for 6 months and were assessed 6 months after treatment. There were 28 sustained viral responders of 232 CIFN-treated patients. Of the sustained responders, 48% had already cleared HCV RNA from serum (<100 copies/mL) by week 2, 78% by week 4, 81% by week 6, and 96% by week 12. Patients with early HCV-RNA clearance were more likely to have sustained responses than those who responded later. Early clearance of HCV from serum was also associated with greater likelihood of a sustained response to 48 weeks of retreatment with 15 microgram CIFN. Ninety-five percent of the sustained responders were HCV-RNA-negative by week 8 of retreatment. Early assessment of HCV RNA may help in the prediction of sustained responses to IFN and allow the value of continued treatment to be determined early in the course of IFN therapy.

Consensus interferon: a novel interferon for the treatment of hepatitis C

Although alpha interferons are currently the only therapies approved for treatment of HCV infection approximately half of the treated patients do not respond to the standard regimen of IFN-alpha-2b 3 MU administered 3 times per week (tiw) for 6 to 12 months. Of those who do demonstrate a response, 50-80% will relapse within 6 months after treatment cessation. Thus, the overall response to treatment is low. This paper focuses on studies that have been conducted with a newly developed interferon, Consensus Interferon (CIFN), in the treatment of chronic Hepatitis C. This type-1 interferon links the most common occurring amino acid sequences at each position of available natural alpha interferons into one 'consensus' protein. The thus synthesized molecule shows a 10-fold higher in vitro biological activity as compared to single recombinant IFN-alpha-2b or IFN-alpha-2a, possibly due to its greater binding affinity to interferon receptors. In patients with chronic hepatitis C, CIFN 9 micrograms, three times weekly for 24 weeks, proved to be equally efficacious and as safe as IFN-alpha-2b, but compared to 3 MU IFN-alpha-2b, CIFN 9 micrograms demonstrated improved responses in patients with high baseline viral titres. Retreatment of subjects who had responded but relapsed following standard dose IFN therapy for 6 months, with 15 micrograms CIFN three times weekly for 48 weeks, resulted in a sustained virological response rate of 58%. When previous non-responders to standard IFN therapy were retreated a 13% sustained response to the higher dose of CIFN for 48 weeks was observed. The higher dose of CIFN was well-tolerated and not associated with an increase in the incidence of side-effects. CIFN proved to be an effective and safe therapy in the treatment of patients with chronic hepatitis C and the retreatment of patients who either failed previous interferon treatment or had relapsed after its cessation.

Long-term retreatment in chronic hepatitis C patients who were non-responders to an initial course of interferon-alpha 2b

Nineteen patients with chronic hepatitis C who were virological non-responders (seven responder/relapse and 12 no response) to an initial 24-week course of interferon-alpha 2b (IFN-alpha 2b) at a dose of 3 million units (MU) thrice weekly were retreated for an additional 48 weeks at the same dosing schedule and followed-up for another 24 weeks post-therapy. At the end of follow-up (week 72), six (32%) of the 19 patients were hepatitis C virus (HCV) RNA negative and were virological complete responders to retreatment. The viral genotypes in these six patients included two each with 1b and 3a, one with 2b, and another with 2a/2b; five of the six virological responder patients had cirrhosis. Significant predictors for successful retreatment included lower baseline HCV RNA concentrations prior to the first course of therapy, 2 log10 reductions in serum HCV RNA during the initial treatment and classification into the virological 'responder/relapse' category after the first course of IFN (P < 0.01 for all observations). When the above factors were used to construct a predictive model to determine response to retreatment, it was found that the absence of a 2 log10 drop in HCV RNA concentrations during the first course of IFN therapy was the most reliable indicator of non-response to retreatment (likelihood ratio = 10, P = 0.0014). In addition, the presence of HCV RNA at week 12 of retreatment was 100% predictive of virological non-response to the 48-week course of therapy. Our findings indicate that an additional 48-week course of IFN-alpha 2b therapy at 3 MU thrice weekly will achieve a virological complete response in 60% of patients who had a 2 log10 drop in HCV RNA during their first course of treatment, and measurement of week-12 HCV RNA during retreatment to identify non-responders is beneficial to patients as well as being cost-effective. Thus, a second course of IFN remains a viable option in a subgroup of non-responder patients, regardless of genotype or the presence of compensated cirrhosis.

The natural course of chronic hepatitis C: implications for clinical practice

Hepatitis C is an important public health problem with high rates of chronic infection ensuing after viral acquisition. The spectrum of the disease ranges from mild to severe chronic hepatitis, cirrhosis and hepatocellular carcinoma. Extra-hepatic manifestations may occur. The disease is complex and predictions about long-term prognosis for individual patients remain difficult. It is generally accepted that 10-20% of patients with chronic hepatitis C will develop cirrhosis within 10 years of first infection: identifying the group of patients at greatest risk remains a primary challenge for clinicians. Older age of infection, duration of infection, degree of liver inflammation at first biopsy and cofactors such as alcohol abuse, all appear to be predictors of a poorer prognosis. The following paper aims to identify some of the features of the natural history of hepatitis C most relevant to the clinician.