Spectrum of virus inhibition by consensus interferon YM643

How to approach and treat viral infections in ICU patients

Patients with severe viral infections are often hospitalized in intensive care units (ICUs) and recent studies underline the frequency of viral detection in ICU patients. Viral infections in the ICU often involve the respiratory or the central nervous system and can cause significant morbidity and mortality especially in immunocompromised patients. The mainstay of therapy of viral infections is supportive care and antiviral therapy when available. Increased understanding of the molecular mechanisms of viral infection has provided great potential for the discovery of new antiviral agents that target viral proteins or host proteins that regulate immunity and are involved in the viral life cycle. These novel treatments need to be further validated in animal and human randomized controlled studies.

Effect of exogenous interferon and an interferon inducer on western equine encephalitis virus disease in a hamster model

Mice are used as models for western equine encephalitis virus (WEEV) infection, but high mortality is generally only seen with intracranial or intranasal challenge, while peripheral inoculation results in approximately 50% mortality and is not dose-dependent. Hamsters were therefore studied as a model for WEEV infection. Hamsters were highly sensitive to intraperitoneal (i.p.) infection with WEEV. Disease progression was rapid, and virus titers in serum, brain, liver, and kidney of infected hamsters peaked between 2 and 4 days post-virus inoculation (dpi). Foci of virus infection were detected in neurons of the cerebral cortex and midbrain. Pre-treatment i.p. with either interferon alfacon-1 (5 microg/kg/day) or with Ampligen (3.2 mg/kg/day) resulted in complete survival, reduced brain titers, and improved weight gain. This model of WEEV infection in hamsters appears to serve as a suitable model for the evaluation of potential therapeutic agents for the treatment of WEE disease.

Adaptation of West Nile virus replicons to cells in culture and use of replicon-bearing cells to probe antiviral action

Flaviviruses are emerging threats to public health worldwide. Recently, one flavivirus, West Nile virus (WNV), has caused the largest epidemic of viral encephalitis in US history. Like other flaviviruses, WNV is thought to cause a persistent infection in insect cells, but an acute cytopathic infection of mammalian cells. To study adaptation of WNV to persistently replicate in cell culture and generate a system capable of detecting antiviral compounds in the absence of live virus, we generated subgenomic replicons of WNV and adapted these to persistently replicate in mammalian cells. Here we report that adaptation of these replicons to cell culture results in a reduction of genome copy number, and demonstrate that hamster, monkey, and human cells that stably carry the replicons can be used as surrogates to detect the activity of anti-WNV compounds. Additionally, we have used these cells to investigate the interaction of WNV genomes with interferon (IFN). These studies demonstrated that IFN can cure cells of replicons and that replicon-bearing cells display lower responses to IFN than their IFN-cured derivatives.

[Interferon alfacon-1 (Advaferon): a novel synthetic interferon for the treatment of hepatitis C, its pharmacological and clinical profile]

Interferon alfacon-1 (Advaferon, also referred to as consensus interferon) is a novel synthetic recombinant type-I interferon (IFN) developed by comparing the amino acid sequences of several natural IFN-alpha subtypes and assigning the most frequently observed amino acid in each corresponding position to generate a consensus molecule. Interferon alfacon-1 binds with high affinity to type-I IFN receptors and has greater biological activity than naturally occurring IFN-alpha as assessed by its increased antiviral, anti-proliferative, and natural killer cell activities, as well as its stronger IFN-stimulated gene induction. In a multicenter, randomized, controlled study, the safety and efficacy of interferon alfacon-1 in comparison with lymphoblastoid interferon-alpha [IFN-alpha (NAMALWA)] was evaluated in patients infected with high-titer chronic hepatitis C virus (HCV). Interferon alfacon-1 (18 MIU) was superior in efficacy without additional toxicity to IFN-alpha (NAMALWA) (9 MIU) in high-titer chronic HCV patients, particularly those infected with genotype 1b. A multicenter open-label study showed that treatment with interferon alfacon-1 (12 MIU) was an effective and tolerable therapy in chronic HCV patients with low viral titers. Another multicenter open-label study showed that re-treatment with interferon alfacon-1 (18 MIU) was an effective and tolerable therapy in chronic HCV patients who relapsed after traditional IFN therapy. Collectively, these clinical studies indicate that interferon alfacon-1, as a novel synthetic interferon, may be a useful therapeutic alternative for the effective treatment of hepatitis C.

Genetically modified interferon: is there a consensus yet?

The treatment of patients with chronic hepatitis C virus infection has evolved during the last decade from interferon monotherapy to combination therapy with interferon and ribavirin. National and international guidelines recommend either 6 or 12 months of interferon/ribavirin combination therapy depending on the pre-treatment virological status of the patient. However, the choice for second-line treatment of patients who do not achieve sustained viral clearance with combination therapy has yet to be defined. This commentary examines previously published studies of the use of consensus interferon for hepatitis C virus infected patients. The characteristics of the treated populations and response to treatment are examined. The current and potential roles for this type of interferon in the treatment of hepatitis C virus infection are considered.

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.