Long-term efficacy of treatment of chronic hepatitis C with alpha interferon or alpha interferon and ribavirin

The fusion protein of IFN-α and apolipoprotein A-I crosses the blood-brain barrier by a saturable transport mechanism

IFN-α is widely used for the treatment of chronic viral hepatitis and malignancies. However, systemic IFN-α treatment causes severe neuropsychiatric complications in humans, including depression, anxiety, and cognitive impairments. We have previously reported that the fusion protein formed by IFN-α and apolipoprotein A-I (IA) circulates bound to high-density lipoproteins (HDLs) and exhibits liver targeting, increased half-life, enhanced immunostimulatory activity, and reduced cytotoxicity. As the transport of HDLs across the blood-brain barrier is a highly complex and regulated process, in this study, we examine the effects of IA on the brain. Determination of IFN-α in brain and serum after hydrodynamic administration of different doses of a plasmid encoding IFN-α or IA showed that IA penetrated into the brain by a saturable transport mechanism. Thus, at high serum levels of the transgenes, the induction of IFN-sensitive genes and the number of phospho-STAT1(+) cell nuclei in the brain were substantially higher with IFN-α than with IA. This was associated with attenuation of neurodepression in mice given IA, as manifested by shorter immobility time in the tail suspension test. However, when given low doses of rIFN-α or the same antiviral units of HDLs containing IA, the induction of IFN-stimulated genes in the brain was significantly greater with the latter. In conclusion, IA crosses the blood-brain barrier not by diffusion, as is the case of IFN-α, but by a facilitated saturable transport mechanism. Thus, linkage to apolipoprotein A-I may serve to modulate the effects of IFN-α on the CNS.

Anchoring interferon alpha to apolipoprotein A-I reduces hematological toxicity while enhancing immunostimulatory properties

Interferon alpha (IFNα) is widely used for the treatment of viral hepatitis but substantial toxicity hampers its clinical use. In this work, we aimed at improving the efficacy of IFNα therapy by increasing the IFNα half-life and providing liver tropism. We selected apolipoprotein A-I (ApoA-I) as the stabilizing and targeting moiety. We generated plasmids encoding IFNα, albumin bound to IFNα (ALF), or IFNα linked to ApoA-I (IA) and mice were treated either by hydrodynamic administration of the plasmids or by injection of the corresponding recombinant proteins or high-density lipoproteins containing IA. The plasma half-life of IA was intermediate between IFNα and ALF. IA was targeted to the liver and induced higher hepatic expression of interferon-stimulated genes than IFNα or even ALF. IA exhibits stronger in vivo antiviral activity than IFNα and the hematologic cytopenic effects of IA are milder than those observed when using IFNα or ALF. In contrast to IFNα, IA does not cause activation-dependent cell death of lymphocytes in vitro. Accordingly, in vivo studies showed that IA boosts T-cell immune responses more efficiently than IFNα or ALF. The difference in immunostimulatory activity between IFNα and IA disappears in scavenger receptor class B type I (SR-BI) knockout mice, suggesting that crosstalk between SR-BI and IFNα receptor is essential for enhanced induction of cytotoxic T cells by IA.

CONCLUSION

Anchoring IFNα to ApoA-I prolongs the half-life of IFNα and promotes targeting to the liver. Importantly, the fusion protein shows increased immunostimulatory properties and lower hematological toxicity.

Persistence of hepatitis C virus in peripheral blood mononuclear cells of sustained viral responders to pegylated interferon and ribavirin therapy

The aim of this paper was to assess the persistence of hepatitis C virus (HCV) among patients successfully treated with peginterferon and ribavirin. The persistence of viral RNA was evaluated in the serum and peripheral blood mononuclear cells (PBMCs) of 25 chronic hepatitis C patients with sustained viral response to peginterferon and ribavirin treatment up to 56 months after the completion of therapy. Viral RNA was detected in the peripheral blood mononuclear cell cultures of five patients (20%), but none had detectable serum HCV RNA. At present, the clinical relevance of this finding is unclear. It is possible that viral persistence and, specifically, the presence of HCV RNA in PBMCs may lead to HCV reactivation under special circumstances, such as immunosuppression.

Peginterferon alfa-2a versus Peginterferon alfa-2b as Initial Treatment of Hepatitis C Virus Infection: A Cost-Utility Analysis from the Perspective of the Veterans Affairs Health Care System

STUDY OBJECTIVE

To assess the cost-utility of peginterferon alfa-2a plus ribavirin, peginterferon alfa-2b plus ribavirin, and no therapy for treatment-naïve patients with chronic hepatitis C virus (HCV) infection from the perspective of the Veterans Affairs (VA) health care system by using patient-reported utility scores.

DESIGN

Cost-utility analysis using a Markov model.

SETTING

Veterans Affairs health care system.

DATA SOURCE

Data for the model were obtained from clinical trials and published literature. Data from the VA health care system were used to define the patient cohorts.

MEASUREMENTS AND MAIN RESULTS

A Markov model incorporating transition probabilities between disease health states that depend only on the current health state was developed to simulate the progression of HCV disease. The patient cohorts were a 45-year-old male cohort and a 55-year-old male cohort, each with liver fibrosis but no cirrhosis. The lifetime expected costs, quality-adjusted life-years (QALYs) gained, and incremental net monetary benefit (INMB) with HCV treatments were determined for each cohort by genotype (genotype 1, and genotypes 2 and 3). Both peginterferon regimens were significantly more cost-effective than no treatment, although no significant differences in costs or QALYs were noted between peginterferon regimens. For the 45-year-old cohort with a genotype 1 infection, the INMB was $128,583 (95% confidence interval [CI] $79,279-$177,308) and $128,025 (95% CI $80,425-$173,448) versus no treatment for peginterferon alfa-2a plus ribavirin and peginterferon alfa-2b plus ribavirin, respectively. Treatment with either peginterferon regimen produced significantly lower lifetime HCV-related medical costs for genotype 2 or 3 infections, but not genotype 1.

CONCLUSIONS

Peginterferon alfa-2a plus ribavirin and peginterferon alfa-2b plus ribavirin were found to be cost-effective treatments for patients with HCV infections, particularly with genotypes 2 and 3. However, no significant differences in costs or efficacy were observed between these peginterferon treatment regimens.

The effect of zinc supplementation on the treatment of chronic hepatitis C patients with interferon and ribavirin

OBJECTIVES

To evaluate the effects of zinc supplementation on serum zinc and copper levels, and the severity of adverse reactions and virologic responses in chronic hepatitis C patients undergoing interferon (IFN)/ribavirin therapy.

DESIGN AND METHODS

Forty subjects were randomly assigned to receive IFN-alpha-2a/ribavirin with or without zinc gluconate for 24 weeks, then a period of 6 months for follow-up. Twenty healthy controls were also enrolled in the study. Blood samples were collected at different time points during therapy and at 6 months after the completion of therapy and were analyzed for zinc and copper levels. The adverse reactions and the virologic responses were also examined accordingly.

RESULTS

Serum zinc levels were significantly lower in chronic hepatitis C patients than in healthy controls and further depressed by IFN/ribavirin treatment. However, serum zinc levels in patients were remediable by zinc supplements. No apparent difference was seen in virologic responses between subjects with or without zinc supplements, but certain adverse side effects associated with the zinc therapy were significantly decreased.

CONCLUSIONS

Zinc supplementation may be a complementary therapy in chronic hepatitis C patients to increase the tolerance to IFN-alpha-2a and ribavirin.

Is it cost-effective to treat recurrent hepatitis C infection in orthotopic liver transplantation patients?

Hepatitis C virus (HCV) recurs in the allograft almost universally after orthotopic liver transplantation (OLT), with a variable course ranging from mild hepatitis to frank cirrhosis. The uncertain prognosis after OLT has lead to widely increased use of antiviral therapy in the post-OLT setting. We compared two scenarios (antiviral therapy versus no antiviral therapy) using a Markov-based decision analytic model to simulate costs and health outcomes for recurrent HCV in three age and sex cohorts of post-OLT patients. Efficacy outcomes included total costs, cases of cirrhosis prevented, cases of death prevented, life-years gained, and cost per life-year saved. One-way sensitivity analyses were performed for sustained viral response; annual drug cost, discount rate, compliance, cirrhosis rate, decompensation rate, and cost of dying. Two-way sensitivity analyses were performed to compare effects of (1) changing sustained viral response and antiviral therapy costs, and (2) changing the sustained viral response and cirrhosis rate. The incremental cost-effectiveness ratio for the reference patient cohort of 1,000 men aged 55 years was $29,100 per life-year saved. The model was sensitive to drug costs, cirrhosis rate, and sustained viral response. The two-way sensitivity analysis showed that antiviral therapy remained cost-effective even if drug costs increased, as long as these increases were associated with higher sustained viral responses. The cost-effectiveness ratio also was sensitive to age and sex of cohort. The decision to treat HCV after OLT with antiviral therapy usually is based on many considerations. Such treatment can be cost-effective if baseline assumptions are met. Our model was sensitive to antiviral drug costs, cirrhosis rate, and sustained viral response. Patients with a progressive course of recurrent HCV are likely to have the greatest gain from antiviral therapy.

Management of viral hepatitis C

The hepatitis C virus was first identified in 1989. It causes chronic hepatitis, cirrhosis and hepatocellular carcinoma. Global anti-HCV prevalence is 1-3%. Contaminated blood product, dirty needles and instruments, and injection drug use are the main parenteral routes of transmission. Cultural practices, such as acupuncture, tattoo, body piercing and scarring, also play a role. Universal precaution is the mainstay for prevention before vaccine is developed. Therapy for chronic hepatitis C (CHC) with interferon (IFN) is not satisfactory. Non-response and early relapse reduce sustained response (SR). In 1997, National Institute of Health consensus recommended IFN therapy only for selected patients with compensated CHC, raised ALT and moderate to severe histologic disease activity; 15-20% SR is expected. Major advances in CHC therapy is combination therapy. Ribavirin in combination with IFN significantly increases SR to 30-40%. Even patients with high viral load, genotype 1, significant fibrosis or cirrhosis respond better. EASL and APASL Consensus in 1999 recommended IFN-ribavirin combination as the first line therapy. Recent data on pegylated IFN showed very encouraging results. Combined with ribavirin, 60% SR was achieved. It benefits patients with severe bridging necrosis and also cirrhosis. However, 23-27% of patients receiving combination therapy with either IFN type, experienced adverse events and required therapy discontinuation. Many important issues remained unsolved. Therapy for children, the elderly, patients with comorbidity and extra-hepatic syndromes need to be addressed. Therapy is too expensive and not affordable to the majority of patients in developing countries.

Prolonging the half-life of human interferon-alpha 2 in circulation: Design, preparation, and analysis of (2-sulfo-9-fluorenylmethoxycarbonyl)7- interferon-alpha 2

Polypeptide drugs are generally short-lived species in circulation. In this study, we have covalently linked seven moieties of 2-sulfo-9-fluorenylmethoxycarbonyl (FMS) to the amino groups of human interferon-alpha2. The derivative thus obtained (FMS(7)-IFN-alpha2) has approximately 4% the biological potency and 33 +/- 4% the receptor binding capacity of the native cytokine. Upon incubation, FMS(7)-IFN-alpha2 undergoes time-dependent spontaneous hydrolysis, generating active interferon with t(1/2) values of 24 +/- 2 h at pH 8.5 and 98 +/- 10 h at pH 7.4. When native IFN-alpha2 is intravenously administered to mice, circulating antiviral activity is maintained for a short duration and then declines with t(1/2) = 4 +/- 0.5 h, reaching undetectable values at approximately 18 h after administration. With intravenously administered FMS(7)-IFN-alpha2, there is a lag period of 2 h, followed by a progressive elevation in circulating antiviral-active protein, which peaked at 20 h and declined with t(1/2) = 35 +/- 4 h. FMS(7)-IFN-alpha2 is resistant to alpha-chymotrypsin digest and to proteolytic inactivation by human serum proteases in vitro. We have thus introduced here an inactive IFN-alpha2 derivative, which is resistant to in situ inactivation and has the capability of slowly reverting to the native active protein at physiological conditions in vivo and in vitro. Having these attributes, FMS(7)-IFN-alpha2 maintains prolonged circulating antiviral activity in mice, exceeding 7-8 times the activity of intravenously administered native cytokine.

Detection of residual hepatitis C virus RNA by transcription-mediated amplification in patients with complete virologic response according to polymerase chain reaction-based assays

A considerable proportion of patients with chronic hepatitis C who achieve a virologic end-of-treatment response relapse after discontinuation of therapy. It is conceivable that polymerase chain reaction (PCR)-based assays with a lower detection limit of 100 to 1, 000 hepatitic C virus (HCV) RNA copies/mL are still too insensitive to detect residual viremia. End-of-treatment serum samples of 47 patients with a virologic relapse according to results of qualitative PCR assays (Amplicor HCV; Roche Molecular Systems, Mannheim, Germany) were tested by transcription-mediated amplification (TMA), an isothermal, autocatalytic target amplification method that has the potential to detect less than 50 HCV RNA copies/mL. Virologic sustained responders (n = 59) and nonresponders (n = 49) served as controls. In end-of-treatment serum samples of virologic sustained responders and nonresponders an almost complete concordance between PCR and TMA results was observed (98%). However, HCV RNA was detectable by TMA in end-of-treatment serum samples from 16 of 25 relapse patients (64%) who were HCV-RNA-negative according to Amplicor HCV version 1.0 (lower detection limit 1,000 copies/mL) and in 8 of 22 patients (36%) who were HCV-RNA-negative according to Amplicor HCV version 2.0 (lower detection limit 100 copies/mL). End-of-treatment alanine transaminase (ALT) levels of sustained virologic responders and TMA-negative relapsers were similar, whereas a trend toward higher ALT values was observed in TMA-positive relapsers compared with sustained virologic responders (P = 0.09). In conclusion, HCV RNA can be detected at the end of treatment by TMA in a considerable proportion of patients who were classified as virologic end-of-treatment responders with a subsequent virologic relapse according to PCR-based methods.