Management strategies for ribavirin-induced hemolytic anemia in the treatment of hepatitis C: clinical and economic implications

A simplified molecularly imprinted ECL sensor based on Mn2SnO4 nanocubes for sensitive detection of ribavirin

Conventional single-signal or emerging sandwich-type double-signal electrochemiluminescence (ECL) immunosensors/aptasensors have offered accurate detection of small molecules, yet suffer from complicated setup, long processing time, and non-reusability. Here, we demonstrate a simplified molecularly imprinted ECL sensor based on Mn2SnO4 nanocubes. As an n-type semiconductor, Mn2SnO4 has numerous active sites that can capture electrons to accelerate chemical reactions, resulting in enhanced ECL activity and stability. For the first time, we verify a robust cathodic ECL emission of Mn2SnO4 luminophores in the presence of K2S2O8 coreactants. The proposed ECL sensor applies to the sensitive detection of ribavirin (RBV), endowing a wide linear range (1-2000 ng mL-1), low detection limit (0.85 ng mL-1, S/N = 3), high stability, specificity, and reproducibility, and the detection capability in real milk and chicken samples. This work highlights single semiconductor luminophore-driven molecularly imprinted ECL sensors, meeting the original aspiration of uncomplicated but high-performance sensing in food safety inspection.

Recent advances in understanding Crimean-Congo hemorrhagic fever virus

Crimean-Congo hemorrhagic fever virus (CCHFV) is a widely distributed hemorrhagic fever virus and the cause of hemorrhagic disease in Africa, Southern and Eastern Europe, the Middle East, India and Asia. Recent emergence of CCHFV into Spain indicates that the geographic range of this virus is expanding and the presence of its tick vector in several countries without reported disease suggest that CCHFV will continue to spread. Research into CCHFV was historically limited by a lack of suitable animal models and tools to study viral pathogenesis. However, in the past few years the toolset for studying CCHFV has expanded with small animal and non-human primate models for CCHFV being developed along with a reverse genetics system that allows for investigation of viral determinants of disease. These tools have been utilized to understand how CCHFV antagonizes host restriction factors and to develop novel vaccine candidates that may help limit the substantial morbidity and mortality in humans caused by CCHFV.

The cost of treating ribavirin-induced anemia in hepatitis C: the impact of using recombinant human erythropoietin

OBJECTIVE

Ribavirin-induced anemia (RIA) is a common adverse effect of chronic hepatitis C treatment. Studies have shown that the use of epoetin decreases the need for ribavirin dose reduction or discontinuation. The primary objective was to calculate the incremental cost of treating hepatitis C in those without versus with RIA, using either the strategy of ribavirin dose reduction/discontinuation or epoetin. The secondary objective was to calculate the incremental cost of using epoetin versus no epoetin to treat RIA, per ribavirin dose reduction/discontinuation averted.

METHODS

Estimates from the literature and decision-analytic techniques were used to model treatment patterns and estimate the cost of managing RIA in genotype 1, 2, and 3 subjects. Sensitivity analyses were used to address uncertainty.

RESULTS

Clinically significant RIA, a reduction in hemoglobin of > or = 2 g/dL (1.2 mmol/L), developed in 72% of patients in observational studies. The incremental cost of treating chronic hepatitis C decreased when employing the strategy of ribavirindose reduction/discontinuation to treat RIA, and increased by 5.7% (genotype 1) or 34.4% (genotype 2 or 3), when using epoetin. Using one-way sensitivity analyses, the cost of using epoetin per ribavirin dose reduction/discontinuation averted was $39,579-$52,023. Generalizability may be limited to settings in which a similar proportion of patients develop RIA.

CONCLUSIONS

The proportional cost of treating hepatitis C when using epoetin to treat RIA is significant in genotype 2 or 3 patients. The cost of using epoetin per ribavirin dose reduction/discontinuation averted is substantial in patients with genotypes 1, 2, or 3; and varies with the probability of response to epoetin. These findings suggest that additional studies are warranted that will determine the effect of epoetin on treatment outcomes and its role as supportive therapy in patients with RIA.

Strategies for managing anemia in hepatitis C patients undergoing antiviral therapy

Anemia is a common side effect that begins soon after the initiation of peginterferon/ribavirin in the treatment of hepatitis C virus (HCV) infection. It can cause symptoms that negatively impact quality of life (QOL) and is the most common reason for reducing the dose and temporarily or permanently discontinuing ribavirin. Such dose modifications have been shown to reduce the efficacy of treatment. Administering erythropoietin can improve anemia caused by peginterferon and ribavirin therapy and is more effective than dose reduction at improving QOL during treatment. However, erythropoietin, which is not approved by the U.S. Food and Drug Administration (FDA) for use in patients with HCV infection, adds another parenteral drug to the patient's treatment regimen, and is associated with additional costs, inconvenience, and potential side effects. A new ribavirin analog, viramidine, is expected to be associated with a lower incidence of anemia and, if proven effective, may eventually be substituted for ribavirin in combination with peginterferon to treat chronic hepatitis C. In the meantime, physicians must make the best possible use of the available options for managing anemia, especially in select patient groups who are most at risk for anemia and its complications.

Cost-effectiveness of growth factors during hepatitis C anti-viral therapy

BACKGROUND

Although the current standard of care for controlling anaemia and neutropenia during anti-viral therapy for hepatitis C is to use dose reduction of ribavirin and pegylated interferon, respectively, erythropoietin and granulocyte colony-stimulating factor are now being advocated as alternatives to dose reduction.

AIM

To determine the cost-effectiveness of erythropoietin and granulocyte colony-stimulating factor as an alternative to anti-viral dose reduction during antihepatitis C therapy.

METHODS

Decision analysis was used to assess cost-effectiveness by estimating the cost of using a growth factor per quality-adjusted life-year gained.

RESULTS

Under baseline assumptions, the cost per quality-adjusted life-year of using growth factors ranged from 16,247 US dollars for genotype 1 with neutropenia to 145,468 US dollars for genotype 2/3 patients with anaemia. These findings are sensitive to the relationship between dose reduction and sustained virological response.

CONCLUSIONS

Based upon our findings and the varying strength of the evidence for a relationship between dose reduction and sustained virological response: granulocyte colony-stimulating factor may be cost-effective for genotype 1 patients; erythropoietin is probably not cost-effective for genotype 2/3 patients; no conclusion can be reached regarding the cost-effectiveness of erythropoietin for genotype 1 patients or granulocyte colony-stimulating factor for genotype 2/3 patients. Randomized trials are needed to firmly establish the relationship between dose reduction and sustained virological response.

Factors Associated with Ribavirin-Induced Anemia

Background:

During treatment of hepatitis C, ribavirin-induced anemia (RIA) requires reduction of the ribavirin dose or initiation of erythropoietin in up to 20% of patients. RIA usually occurs in the first 8 weeks of treatment, and a decrease >3 g/dL or a nadir <10 g/dL is considered significant.

Objective:

To prospectively examine factors associated with RIA in a population of patients with hepatitis C.

Methods:

Consecutive patients with hepatitis C (hepatitis B virus and HIV negative) underwent treatment with pegylated interferon and weight-based ribavirin. Prospectively gathered data included demographics, alcohol consumption, and hepatitis C virus risk factors. Patients underwent laboratory studies at baseline and at intervals of 4–8 weeks after starting treatment.

Results:

One hundred eight patients were enrolled. Of these, 30 (27.8%) experienced a >3 g/dL fall in hemoglobin levels in the first 8 weeks; in 10 (33%) patients, the change occurred by week 4. The initial hemoglobin level was higher in those with a decrease compared with those without a fall (15.3 vs 14.1 g/dL; p < 0.001). In addition, for patients with a decrease, the iron saturation was higher (44.6% vs 30.1%; p = 0.002). Finally, those with fibrosis stage 6/6 (cirrhosis) had a greater percent fall in hemoglobin (27.0% vs 14.0%; p = 0.009) than those with less severe fibrosis. By logistic regression analysis, only iron saturation was associated with RIA (p = 0.002).

Conclusions:

In our patients, initial hemoglobin, serum iron, and fibrosis were associated with a potentially clinically important decrease in hemoglobin. In approximately one-third of the population, RIA occurred in the first 4 weeks of treatment. No patient had a severe complication.

Epoetin alfa for the treatment of combination therapy-induced hemolytic anemia in patients infected with hepatitis C virus

In the United States, about 2.7 million people are chronically infected with the hepatitis C virus, accounting for nearly 1.8% of the population. The current standard of therapy is a combination of pegylated interferon products and ribavirin. A common adverse effect associated with this therapy is anemia, which is frequently referred to as mixed anemia because of the synergistic contribution of the interferons and ribavirin. The effect of ribavirin on the development of anemia is considered greater than that of interferon. The current standard of practice for treating this adverse effect is reduction of the dosages of both drugs, at prespecified hemoglobin levels. However, recent findings underscore the importance of maintaining adequate dosages of interferon and ribavirin, which may be crucial in achieving an early virologic response and a sustained virologic response in treating patients with hepatitis C infection. Treatment with epoetin alfa for this mixed anemia significantly improved hemoglobin levels and quality of life, and enabled adequate dosages of ribavirin to be maintained. Future studies should address several issues: when to start epoetin alfa treatment, the duration of treatment, the drug's optimal dosage, its effects on end-of-treatment and sustained virologic response rates, and a cost analyses.

Hematologic side effects of interferon and ribavirin therapy

Pegylated (PEG)-interferon and ribavirin combination therapy are the standard of care for the treatment of chronic hepatitis C and are associated with a high rate of sustained virologic response. However, there is a high incidence of hematologic side effects with this therapeutic regimen. Hematologic side effects are particularly common; bone marrow suppression caused by interferon may result in neutropenia and thrombocytopenia. Ribavirin is directly toxic to red blood cells and is associated with hemolysis, which is usually dose-related but self-limited. Historically, the traditional management of hematologic side effects of interferon therapy has been dose reduction. However, recent studies have shown that response to therapy is strongly influenced by adherence to optimal doses of interferon and particularly ribavirin. Therefore, there is increasing emphasis on the use of growth factors such as filgrastim and erythropoietin to stimulate bone marrow production of erythrocytes and leukocytes to allow patients to receive the optimal doses of interferon and ribavirin. The incidence, magnitude, and possible mechanisms of hematologic complications associated with interferon and ribavirin are described in this review.

Epoetin alfa treatment for acute anaemia during interferon plus ribavirin combination therapy for chronic hepatitis C

Infection with the hepatitis C virus (HCV) remains chronic in 75% of infected individuals, in whom it can cause liver inflammation and progressive fibrosis leading to cirrhosis in 20% of patients. A sustained viral response (SVR) to HCV therapy, i.e. undetectable plasma HCV RNA 6 months after the end of treatment, leads to permanent eradication of the virus in 98.3% of patients. The current treatment of choice is combination therapy with pegylated interferon alfa (PEG-IFN alfa), 2a or 2b, and ribavirin (RBV), which achieves an SVR in 54-56% of patients. In patients with HCV genotype 1, RBV doses of 1000-1200 mg/day are associated with a higher SVR than 800 mg/day (51 vs 40%). However, RBV also causes dose-dependent reversible haemolytic anaemia that, in combination with the myelosuppressive effects of PEG-IFN, results in a mean drop in haemoglobin (Hb) level of 3.7 g/dL within 4 weeks. Conventionally, this acute anaemia has been managed with RBV dose reductions. However, this may result in a decreased SVR rate. Alternatively, this anaemia can be managed with administration of epoetin alfa at 40 000 IU once weekly. In a randomized placebo-controlled trial, treatment with epoetin alfa has been shown to raise Hb levels and maintain RBV doses. Furthermore, the increase in Hb level was associated with improved quality of life. Anaemia in patients treated with interferon plus RBV combination therapy can be managed effectively and safely with once weekly epoetin alfa without sacrificing optimal dosing of RBV.

Role of epoetin alfa in maintaining ribavirin dose

Current therapy for the treatment of hepatitis C virus (HCV) infection is standard interferon (IFN) or pegylated interferon (PEG-IFN) in combination with ribavirin (RBV). Hematologic side effects (neutropenia, thrombocytopenia, anemia) are a major reason for dose reduction of anti-HCV therapy. Because treatment adherence and maintenance of IFN or PEG-IFN and RBV doses have been shown to be important in achieving a sustained virologic response, appropriate management of hematologic side effects might play a substantial role in optimizing treatment outcomes. Neutropenia and thrombocytopenia are usually managed by IFN or PEG-IFN dose reduction; the role of hematopoietic growth factors to ameliorate these side effects needs further evaluation, but some studies suggest granulocyte colony-stimulating factor (G-CSF) may be useful in the management of IFN/PEG-IFN-associated neutropenia. Anemia is primarily due to RBV-induced hemolytic anemia, but IFN/PEG-IFN also suppresses bone marrow erythroid precursors. Treatment-induced anemia has usually been managed by RBV dose reduction or discontinuation. However, recent studies suggest that epoetin alfa can increase hemoglobin levels and facilitate maintenance of RBV dosage in patients with chronic hepatitis C who became anemic during standard combination therapy. Results of a randomized, randomized, double-blind, placebo-controlled trial suggest that epoetin alfa therapy can maintain RBV dosage, increase hemoglobin levels, and improve quality of life in this population. In patients who have chronic hepatitis C who experience hematologic toxicities during standard therapy, the use of hematopoietic growth factors such as epoetin alfa might have the potential to improve treatment adherence rates and allow optimal doses of IFN or PEG-IFN and RBV to be maintained, thereby leading to improved treatment outcomes.

Cost-effectiveness analysis of therapeutic strategies for patients with chronic hepatitis C previously not responding to interferon

BACKGROUND

The efficacy of combination therapy in patients with chronic hepatitis C previously not responding to interferon monotherapy is lower than that in naive patients, and there has been no economic evaluation in this population.

AIM

To develop a cost-effectiveness analysis of therapeutic regimens with interferon-alpha and ribavirin in previous interferon non-responders.

METHODS

A Markov simulation model was used to project the clinical and economic outcomes of five different therapeutic strategies, including a 'no treatment' alternative, using the health care system perspective. The efficacy data for the different doses and durations were obtained from a previously performed meta-analysis. A sensitivity analysis was performed to test the robustness of the model, analysing changes in different variables.

RESULTS

Applying a 3% discount rate, the standard patient on combination therapy for 12 months showed increases of 0.80 years and 1.55 quality-adjusted life years, when compared with the 'no treatment' strategy. This option led to an incremental cost-effectiveness ratio of 11,767 euros per year of life gained and 6073 euros per quality-adjusted life year.

CONCLUSIONS

Combination therapy with interferon plus ribavirin is cost-effective in previous interferon non-responders and is within the range of some well-accepted medical interventions in our health care system.

Understudied populations with hepatitis C

Managing patients with hepatitis C virus (HCV) infection consists primarily of antiviral treatment, currently with peginterferon and ribavirin. Unfortunately, treatment recommendations derive largely from trials that have focused on highly selected patient populations. As a consequence of the strict inclusion and exclusion criteria in these studies, more than half of all HCV-infected patients would be ineligible for enrollment. Even among the selected patients enrolled into studies, only 50% achieve a sustained virological response (SVR). Patients not eligible for current therapies include those with mild disease and normal alanine aminotransferase (ALT) levels, patients with advanced and decompensated liver disease, children, the elderly, patients with ongoing or recent alcohol and substance abuse, renal disease, human immunodeficiency virus (HIV) infection, severe psychiatric or neurologic illness, autoimmune disorders, solid organ transplant, and other significant comorbid conditions. Because these patients have been excluded from most clinical trials, little is known about the safety or efficacy of therapy in these populations. The expense and side effects of therapy are also an impediment to treatment of patients who are on public assistance, in prisons, and in institutions. Clearly, new efforts and new approaches are needed to expand the eligibility for antiviral therapy of hepatitis C and make treatment more available for understudied populations with this disease.

Understudied populations with hepatitis C

Managing patients with hepatitis C virus (HCV) infection consists primarily of antiviral treatment, currently with peginterferon and ribavirin. Unfortunately, treatment recommendations derive largely from trials that have focused on highly selected patient populations. As a consequence of the strict inclusion and exclusion criteria in these studies, more than half of all HCV-infected patients would be ineligible for enrollment. Even among the selected patients enrolled into studies, only 50% achieve a sustained virological response (SVR). Patients not eligible for current therapies include those with mild disease and normal alanine aminotransferase (ALT) levels, patients with advanced and decompensated liver disease, children, the elderly, patients with ongoing or recent alcohol and substance abuse, renal disease, human immunodeficiency virus (HIV) infection, severe psychiatric or neurologic illness, autoimmune disorders, solid organ transplant, and other significant comorbid conditions. Because these patients have been excluded from most clinical trials, little is known about the safety or efficacy of therapy in these populations. The expense and side effects of therapy are also an impediment to treatment of patients who are on public assistance, in prisons, and in institutions. Clearly, new efforts and new approaches are needed to expand the eligibility for antiviral therapy of hepatitis C and make treatment more available for understudied populations with this disease.

Premature discontinuation of interferon plus ribavirin for adverse effects: a multicentre survey in 'real world' patients with chronic hepatitis C

BACKGROUND

Interferon-alpha plus ribavirin therapy for chronic hepatitis C is associated with adverse effects that lead to therapy discontinuation in up to 27% of patients in randomized controlled trials.

AIM

To examine the causes and predictive factors for therapy discontinuation in patients treated in current clinical practice.

METHODS

We retrospectively enrolled 441 consecutive patients, scheduled to receive interferon-alpha + ribavirin for chronic hepatitis C, in five centres. Patients had been treated with 3 or 6 MU interferon-alpha three times a week plus ribavirin, 800-1200 mg daily, for 6 or 12 months.

RESULTS

One hundred and eight [24.5%; confidence interval (CI), 20.5-28.8%] patients failed to finish combination therapy because of adverse events. The discontinuation rate was higher during the first 6 months of treatment; anaemia was an important cause (36.1% of discontinuations); unexplained lipothymia resulted in discontinuation in 11 patients. Female gender [hazard ratio (HR) = 1.85; CI, 1.17-2.92], an interferon-alpha dose > 15 MU/week (HR = 1.79; CI, 1.12-2.86) and no previous interferon-alpha treatment (HR = 1.63; CI, 1.04-2.57) were independent factors associated with discontinuation. The simultaneous presence of these factors identified patients at high risk for discontinuation [odds ratio (OR) = 10; CI, 3.98-25.13].

CONCLUSIONS

The study identified some predictive factors for adverse event-related discontinuation, which may improve the safety profile and effectiveness of interferon-alpha + ribavirin combination therapy in chronic hepatitis C.