10-Year follow-up after interferon-alpha therapy for chronic hepatitis C

How physicians describe outcomes to HCV therapy: prevalence and meaning of "cure" during provider-patient in-office discussions of HCV

BACKGROUND

How physicians convey information about hepatitis C virus (HCV) impacts patients' perceptions of treatment outcomes and informed therapy decisions. However, HCV patients reported difficulties communicating with their physicians in a recent study. Another study showed that 45% of patients did not understand projected response rates conveyed by providers, and patients with unfavorable projected treatment outcomes were more likely to lack understanding.

GOALS

This article analyzes naturally occurring patient-provider interactions to evaluate physicians' use of the word 'cure', and framing of HCV response as optimistic, pessimistic, or neutral, to suggest possible reasons why patients with unfavorable projected sustained virologic response rates might perceive their odds as more favorable than they are.

STUDY

Gastroenterologists, allied health professionals, and HCV patients were video and audio-recorded during regular scheduled visits. Recordings were transcribed and analyzed using validated sociolinguistic techniques.

RESULTS

Sixty-three percent of physicians used the word 'cure' in 38% of visits involving response discussions. 'Cure' most frequently meant 'absolute cure' and occurred more commonly in visits conducted before therapy initiation, and with patients having favorable genotypes. Physicians hedged the meaning of 'cure' in 29% of visits. Moreover, 69.5% of response-related utterances were framed optimistically.

CONCLUSIONS

HCV dialogs are characterized by the prevalence of 'cure' and optimistic framing. These positive language attributes could potentially contribute to the misunderstanding regarding the projected response rates. During treatment outcome discussions, the physicians should attempt to (1) operate using the same definition of the therapy outcome as the patient, (2) balance medically accurate information with patient comprehension, and (3) consider possible consequences of discussing treatment options on the basis of message framing.

Hepatitis C for addiction professionals

A disease whose reputation is often worse than its reality, hepatitis C is usually benign. Most infected individuals do not experience symptoms requiring treatment, and roughly half of those treated will become free of detectable virus for an extended, perhaps permanent, period. Moreover, a growing body of data suggests that drug users can attain successful treatment outcomes, even when not completely abstinent. Addiction professionals belong in the forefront of prevention and management of this disease. We can assist our patients by helping them stabilize their lifestyles, correcting misperceptions about the disease, teaching prevention and health maintenance, promoting access to diagnosis and treatment, monitoring for treatment side effects, and providing encouragement to remain in treatment.

Outcome of screening for hepatitis C virus infection based on risk factors

OBJECTIVES

Screening for hepatitis C virus (HCV) infection in individuals at increased risk is currently recommended by most, but not all, health authorities. This study identifies outcomes of individuals diagnosed through a screening program targeting high-risk patients.

METHODS

Veterans presenting for care in VA facilities are assessed for HCV risk factors by a questionnaire. Those with a risk factor are offered anti-HCV testing. Between October 1998 and May 2004, 25,701 patients were assessed and 8,471 patients had a risk factor for HCV. Patients diagnosed through the screening program were assessed per study protocol.

RESULTS

The prevalence of a positive HCV antibody in veterans who identified a risk factor was 7.3% (95% CI 6.6-8.0%). Among those diagnosed through the screening program (N = 260), 47% had chronic hepatitis C. Among patients with chronic HCV, 18% had evidence of advanced liver disease (stage III/IV on biopsy or clinical cirrhosis) while 34% had persistently normal alanine aminotransferase (ALT). Two-thirds of individuals who underwent liver biopsy had minimal or no fibrosis. About half (47%) of the screen-detected patients with chronic HCV were treatment candidates. Forty-four percent were not immediate candidates secondary to medical or psychiatric comorbidities or active substance abuse. Twenty-two patients (8%) had died after a median follow-up of 911 days. Two were liver-related deaths.

CONCLUSION

Screening for hepatitis C in persons at high risk can lead to early identification of individuals at risk for progressive liver disease who may benefit from antiviral therapy and counseling to reduce HCV-related liver injury.

Peginterferon alfa-2b and ribavirin combination therapy for chronic hepatitis C

Pegylated interferon and ribavirin have been the standard treatment for chronic hepatitis C (CHC) since 2001. In the USA, hepatitis C is the most common blood-borne infection and the leading cause of cirrhosis requiring liver transplantation. Due to heightened awareness, more patients are being screened and diagnosed with CHC. Interferon-based therapy will continue to be a mainstay of treatment for years to come. A familiarity with the drugs used for the treatment of CHC is beneficial for most healthcare providers. This article will discuss the use of peginterferon alfa-2b and ribavirin, including dosing, length of treatment, mechanism of action, pharmacodynamics, pharmacokinetics, side effects, monitoring and contraindications, and will provide a future perspective on the treatment of CHC.

Interferon-based therapy of hepatitis C

In 2007, the world celebrated the 50th anniversary of the discovery of interferon (IFN). The first clinical trial of recombinant IFN-alpha in patients with chronic hepatitis C was published in 1986. This article reviews the classification of IFNs, IFN production during viral infections, IFN signaling pathways and the mechanisms of their antiviral and immunomodulatory properties. Hepatitis C virus infection treatment is currently based on the combination of pegylated IFN-alpha and ribavirin. The pegylated IFN-alpha molecules are described, as well as the putative mechanisms of action of ribavirin. Current treatment guidelines are discussed and new results suggesting that the treatment schedule should be tailored to the early virological response during therapy are presented. Finally, insights into new hepatitis C drug developments are given.

Antiviral therapy for chronic hepatitis C in patients with inherited bleeding disorders: an international, multicenter cohort study

BACKGROUND

Hepatitis C is a major co-morbidity in patients with hemophilia. However, there is little information on the efficacy of antiviral therapy and long-term follow-up after treatment.

OBJECTIVES

To assess the effect of interferon-based (IFN-based) therapy on hepatitis C virus (HCV) eradication, to identify determinants associated with treatment response, and to assess the occurrence of end-stage liver disease (ESLD) after completing antiviral therapy.

PATIENTS AND METHODS

In a multicenter cohort study, 295 treatment-naïve hemophilia patients chronically infected with HCV were included. The effect of therapy was expressed as sustained virological response (SVR). Determinants associated with treatment response were expressed as odds ratios (ORs). Cumulative incidence of ESLD was assessed using a Kaplan-Meier survival table.

RESULTS

Among human immunodeficiency virus (HIV) negative patients (n = 235), SVR was 29% (29/101) for IFN monotherapy, 44% (32/72) for IFN with ribavirin, and 63% (39/62) for pegylated IFN (PegIFN) with ribavirin. In patients co-infected with HIV (n = 60), IFN monotherapy, IFN with ribavirin, and PegIFN with ribavirin eradicated HCV in 7/35 (20%), 1/2 (50%), and 11/23 (48%), respectively. SVR increased with genotype 2 and 3 [OR 11.0, 95% CI: 5.8-20.5], and combination therapy (IFN and ribavirin OR 3.7, 95% CI: 1.7-8.4), PegIFN and ribavirin (OR 4.2, 95% CI: 1.8-9.5). Up to 15 years after antiviral treatment, none of the patients with a SVR relapsed and none developed ESLD. In contrast, among unsuccessfully treated patients the cumulative incidence of ESLD after 15 years was 13.0%.

CONCLUSIONS

Successful antiviral therapy appears to have a durable effect and reduces the risk of ESLD considerably.

WITHDRAWN: Ribavirin with or without alpha interferon for chronic hepatitis C

BACKGROUND

Hepatitis C is a major cause of liver-related morbidity and mortality. Ribavirin plus interferon combination therapy is presently considered the optimal treatment of interferon naive patients with chronic hepatitis C, but its role in relapsers and non-responders to previous interferon therapy is not established.

OBJECTIVES

To assess the efficacy and safety of ribavirin alone or in combination with alpha interferon in interferon naive patients, relapsers, and non-responders with chronic hepatitis C.

SEARCH STRATEGY

Eligible trials were identified through searches on electronic databases: The Cochrane Hepato-Biliary Group Controlled Trials Register (August 2001), The Cochrane Controlled Trials Register on The Cochrane Library Issue 3, 2001, MEDLINE (1966 - August 2001), and EMBASE (1985 - August 2001). Manual searches of bibliographies and journals were done as well as authors of trials and pharmaceutical companies producing ribavirin or interferon were contacted.

SELECTION CRITERIA

We included all randomised trials comparing ribavirin with or without alpha interferon versus no intervention, placebo, or alpha interferon for chronic hepatitis C.

DATA COLLECTION AND ANALYSIS

The primary outcome measures were the 'sustained' (six months after treatment) virological response, and morbidity plus mortality. The secondary outcome measures were the 'end of treatment' and 'sustained' biochemical response, the 'end of treatment' virologic response, histology, quality of life, and adverse events.

MAIN RESULTS

We included eight trials in which 271 patients were randomised to ribavirin versus placebo or no intervention and 48 trials in which 6585 patients were randomised to interferon with or without ribavirin. Compared with placebo or no intervention, ribavirin monotherapy had no significant effect on the virological response or histology and only a transient effect on the biochemical response. Compared with interferon, combination therapy reduced the risk of not having a sustained virological response by 26% in naive patients (relative risk (RR) 0.74; 95% confidence interval (CI) 0.70-0.78), 33% in relapsers (RR 0.67; 95% CI 0.57-0.78), and 11% in non-responders (RR 0.89; 95% CI 0.83-0.96). There was no significant effect on morbidity plus mortality (Peto odds ratio 0.45; 95% CI 0.19-1.06). Irrespective of previous therapy, combination therapy significantly reduced the risk of not having a sustained biochemical response (RR 0.76; 95% CI 0.59-0.84) or improved histology (RR 0.67; 95% CI 0.56-0.81). Combination therapy also significantly increased the risk of treatment discontinuation (RR 1.28; 95% CI 1.07-1.52) and several types of adverse events.

AUTHORS' CONCLUSIONS

Combination therapy increased the number of naive patients, relapsers, and non-responders with a sustained virological, biochemical, or histological response, but also the occurrence of adverse events.

Cost-effectiveness of treatment for hepatitis C in an urban cohort co-infected with HIV

PURPOSE

Recent clinical trials have evaluated treatment strategies for chronic infection with hepatitis C virus (HCV) in patients co-infected with human immunodeficiency virus (HIV). Our objective was to use these data to examine the cost-effectiveness of treating HCV in an urban cohort of co-infected patients.

METHODS

A computer-based model, together with available published data, was used to estimate lifetime costs (2004 US dollars), life expectancy, and incremental cost per year of life saved (YLS) associated with 3 treatment strategies: (1) interferon-alfa and ribavirin; (2) pegylated interferon-alfa; and (3) pegylated interferon-alfa and ribavirin. The target population included treatment-eligible patients, based on an actual urban cohort of HIV-HCV co-infected subjects, with a mean age of 44 years, of whom 66% had genotype 1 HCV, 16% had cirrhosis, and 98% had CD4 cell counts >200 cells/mm3.

RESULTS

Pegylated interferon-alfa and ribavirin was consistently more effective and cost-effective than other treatment strategies, particularly in patients with non-genotype 1 HCV. For patients with CD4 counts between 200 and 500 cells/mm3, survival benefits ranged from 5 to 11 months, and incremental cost-effectiveness ratios were consistently less than $75,000 per YLS for men and women of both genotypes. Due to better treatment efficacy in non-genotype 1 HCV patients, this group experienced greater life expectancy gains and lower incremental cost-effectiveness ratios.

CONCLUSIONS

Combination therapy with pegylated interferon-alfa and ribavirin for HCV in eligible co-infected patients with stable HIV disease provides substantial life-expectancy benefits and appears to be cost-effective. Overcoming barriers to HCV treatment eligibility among urban co-infected patients remains a critical priority.

Changing treatment paradigms: hepatitis C virus in HIV-infected patients

The evaluation of hepatic histology and treatment of hepatitis C virus (HCV)/HIV-coinfected patients is rapidly changing. HCV has become an important cause of mortality in HIV-infected patients. Consequently, assessment of liver histology in all coinfected patients is particularly important. The evaluation of hepatic histology is shifting from reliance on the liver biopsy toward noninvasive modalities. Additionally, the importance of HCV-associated morbidity and mortality in HIV-infected patients has prompted increasing numbers of these patients to be HCV treatment candidates. Prospective trials in coinfected patients have reported lower sustained virologic responses compared to HCV-monoinfected patients. Consequently, the numbers of coinfected nonresponders to pegylated interferon/ribavirin continues to increase. Because none of the presently available treatment modalities for pegylated interferon/ribavirin nonresponders are clearly efficacious, management decisions must be individualized. The options include, HCV-specific medications, maintenance therapy, the use of alternative interferon formulations, and observation. HCV-specific agents, particularly protease and polymerase inhibitors, show early promise in HCV-monoinfected individuals. Their use in coinfected patients, however, is likely to be delayed for several years, and they are likely to be used in combination with interferon. Low-dose pegylated interferon, administered in an attempt to slow fibrosis progression (maintenance therapy), is being evaluated in several large prospective trials in monoinfected and coinfected patients. Observation may be best for nonresponders with relatively mild hepatic histology. In summary, HCV treatment will likely follow the example forged by HIV. In the near future, combinations of different drugs will likely be used simultaneously to result in durable viral suppression.

Improving the treatment of hepatitis C infection in the UK

The UK lags behind its European neighbours in the identification and treatment of hepatitis C virus infection. Having recognised this problem, national guidelines are evolving based on detailed examination of clinical evidence. This article reviews recommended treatments for hepatitis C virus infection in the UK, recent advances in the understanding of how to use these treatments and new developments.

Improving anti-hepatitis C virus therapy

The estimated prevalence of hepatitis C virus (HCV) infection is 2%, representing 123 million infected individuals worldwide. HCV infection burdens public health in relation to hepatic (cirrhosis and its complications in 20% of patients) and extrahepatic (vasculitis) complications, and lessens quality of life. Major progress has been made in the last two decades for the diagnosis and treatment of HCV, including more appropriate screening strategies for HCV infection (improved sensitivity of serological and virological tests); a better evaluation of the impact of chronic HCV infection on the liver (semi-quantitative scoring systems of necro-inflammation and fibrosis on liver biopsy, non-invasive evaluation of fibrosis with biochemical markers and elastometry); and improved therapeutic regimens. This progress provides a better definition of who to treat (clinical impact or significant fibrosis); how to treat; tailoring therapies for doses and durations of the pegylated interferon plus ribavirin combination according to virological (mainly genotype and early viral kinetics, but also baseline viral load) and hosts factors (fibrosis, immune status, weight); and how to monitor efficacy and tolerance of therapy. The progress has now resulted in a 50% rate of complete HCV eradication, ranging 45 - 90% according to the genotype and especially in those patients with early viral response. New therapies, specifically HCV protease or polymerase inhibitors, in combination with pegylated interferon, or more potent and less toxic new formulations of interferons or ribavirin, will increase these encouraging results in the future.

Screening in liver disease

A disease is suitable for screening if it is common, if the target population can be identified and reached and if both a good screening test and an effective therapy are available. Of the most common liver diseases only viral hepatitis and genetic hemochromatosis partially satisfy these conditions. Hepatitis C is common, the screening test is good and the therapy eliminates the virus in half of the cases, but problems arise in the definition of the target population. In fact generalized population screening is not endorsed by international guidelines, although some recommend screening immigrants from high prevalence countries. Opportunistic screening (case finding) of individuals with classic risk factors, such as transfusion before 1992 and drug addiction, is the most frequently used strategy, but there is disagreement whether prison inmates, individuals with a history of promiscuous or traumatic sex and health care workers should be screened. In a real practice setting the performance of opportunistic screening by general practitioners is low but can be ameliorated by training programs. Screening targeted to segments of the population or mass campaigns are expensive and therefore interventions should be aimed to improve opportunistic screening and the detection skills of general practitioners. Regarding genetic hemochromatosis there is insufficient evidence for population screening, but individual physicians can decide to screen racial groups with a high prevalence of the disease, such as people in early middle age and of northern European origin. In the other cases opportunistic screening of high risk individuals should be performed, with a high level of suspicion in case of unexplained liver disease, diabetes, juvenile artropathy, sexual dysfunction and skin pigmentation.

HCV RNA detection by TMA during the hepatitis C antiviral long-term treatment against cirrhosis (Halt-C) trial

For making treatment decisions related to chronic hepatitis C, the utility of HCV RNA tests with increased sensitivity has not been defined. Prior interferon nonresponders with advanced fibrosis (n = 1,145) were retreated with peginterferon alpha-2a and ribavirin. Patients who were HCV RNA-negative by a polymerase chain reaction (PCR)-based assay (Roche COBAS Amplicor HCV Test, v. 2.0; lower limit of detection [LOD] 100 IU/mL) at week 20 (W20) received treatment for 48 weeks. Stored specimens were tested using the Bayer VERSANT HCV RNA Qualitative (TMA) Assay (LOD 9.6 IU/mL) and compared to PCR results for the ability to predict sustained virological response (SVR; defined as undetectable HCV RNA by PCR at W72). Nearly all PCR-positive samples (1006/1007, 99.9%) were positive as assessed by TMA. Among 1,294 PCR-negative samples, 22% were TMA-positive. Negative TMA results were more predictive of SVR than were negative PCR results at W12 (82% vs. 64%, P < .001) and at W20 (66% vs. 52%, P = 0.001). SVR was more likely the earlier TMA had become negative during treatment (82% at W12, 44% at W20, 20% at W24). Among 45 patients who were TMA-positive but were PCR-negative at W20 and W24, none achieved SVR (95% CI: 0%-8%). Approximately 10% of patients with a single positive TMA result at the end of treatment still achieved SVR. In conclusion, negative TMA results at or after W12 were superior to negative PCR results for predicting SVR. In patients with negative PCR results during treatment, a single positive TMA test did not exclude SVR, although persistently positive tests did.

Hepatic fibrosis, stellate cells, and portal hypertension

Hepatic fibrogenesis is the common result of injury to the liver. It is believed to be a critical factor that leads to hepatic dysfunction and may be important in portal hypertension. The fibrogenic response is a complex process in which accumulation of extracellular matrix proteins, tissue contraction, and alteration in blood flow are prominent. A critical event in fibrogenesis is activation of resident perisinusoidal cells that are termed "hepatic stellate cells". Stellate cell activation is characterized by many important phenotypes, including enhanced extracellular matrix synthesis and prominent contractility. Given the central role of stellate cell activation in hepatic fibrogenesis (and portal hypertension), effective therapy for hepatic fibrogenesis is most likely will be directed at this event.

Long-term effect of interferon alpha-2b plus ribavirin therapy on incidence of hepatocellular carcinoma in patients with hepatitis C virus-related cirrhosis

We assessed the efficacy of interferon (IFN) alpha-2b plus ribavirin therapy in patients with hepatitis C virus (HCV)-related cirrhosis, and elucidated the risk factors for the development of hepatocellular carcinoma (HCC) to determine whether these therapies might reduce the incidence of HCC. One hundred and thirty-two HCV-cirrhotic patients receiving IFN alpha-2b (3 or 5 MU thrice weekly) and oral ribavirin (1,000-1,200 mg/day) for 24 or 48 weeks were analysed. Cumulative incidence of HCC was estimated by the Kaplan-Meier method. The prognostic relevance of clinical variables and HCC occurrence was evaluated by univariate analysis with the log-rank test and by multivariate Cox's regression analysis. A total of 116 patients completed the treatment and 73 (55%) achieved a sustained virological response (SVR). Stepwise logistic regression analysis showed that nongenotype 1b (P < 0.001) and low viral load (P = 0.018) were independent variables of SVR. During a median follow-up period of 37 (12-63) months, HCC developed in 11 patients with non-SVR and five with SVR (P = 0.0178), whereas there was no difference between those with transient biochemical response and nonresponse (P = 0.5970). The Kaplan-Meier method also showed that old age (>or=60 years) (P = 0.0034) and genotype 1b (P = 0.0104) were associated with HCC occurrence. Using Cox's regression analysis, non-SVR (odds ratio = 3.521, P = 0.036), male (odds ratio = 6.269, P = 0.011) and old age (odds ratio = 3.076, P = 0.049) were independent significant risk factors contributing to HCC development. Our results suggest that achieving SVR by IFN alpha-2b plus ribavirin therapy may decrease the incidence of HCC in patients with HCV-related cirrhosis.

HIV-related liver disease: infections versus drugs

HIV-infected individuals have myriad causes of hepatotoxicity that range from mild hepatitis to significant liver failure with its associated morbidity and mortality, especially in the setting of chronic viral hepatitis (HCV and HBV). Immune restoration by HAART therapy can contribute liver-related toxicity in HIV-coinfected patients. Clinicians need to be aware of this problem and individualize management in this challenging clinical scenario. Avoidance of potentially hepatotoxic agents or close monitoring during treatment of HIV may prevent liver failure in patients who have HIV. Furthermore, vaccination against hepatitis A virus and HBV in nonimmune HIV individuals may prevent acquisition of hepatitis A virus and HBV infections in patients who have HIV. Finally, treatment of HIV, and, if appropriate, treatment of those who are coinfected with HCV and HBV with close monitoring, may improve the outcome of patients who have HIV and are at risk fo r significant hepatotoxicity during treatment from immune restoration or hypersensitivity reactions.

Sustained virological response rates and durability of the response to interferon-based therapies in hepatitis C patients treated in the clinical setting

International controlled trials have demonstrated increasing sustained virological response (SVR) rates to interferon-based therapies in hepatitis-C-treated patients. Response rates of 6-20% in the era of interferon monotherapy are compared with 42-82% with pegylated interferon plus ribavirin. The virological durability of the SVR is unknown and the optimal follow-up for these patients is unclear. The aim of our study was to determine SVR rates and the durability of the response to interferon-based therapies in the clinical setting. From our database of 1540 hepatitis C patients, 344 treatment courses of at least 12 weeks duration were identified, including interferon monotherapy (175 patients), interferon plus ribavirin (96 patients) and peginterferon plus ribavirin (73 patients). Interferon monotherapy was associated with an SVR rate of 5% in 103 genotype 1 patients and 25% in 72 genotype 2/3 patients. Response rates were higher (P < 0.001) with interferon plus ribavirin-41% in 34 genotype 1 patients and 73% in 62 genotype 2/3 patients-and with peginterferon plus ribavirin-47% in 47 genotype 1 patients and 79% in 26 genotype 2/3 patients. Of 147 patients with an SVR, 146 (>99%) remained hepatitis C virus PCR negative during a mean 2.3 years (range 0.3-10.3) of follow-up. In conclusion, with advances in therapies, we are achieving higher response rates in hepatitis C patients treated in the clinical setting. We can now expect an SVR in over half of the treated patients. Importantly, the response is durable and medium and long-term follow-up of these patients are of low yield and largely unnecessary.

Effect of anti-viral therapy for occult hepatitis C virus infection

BACKGROUND

Occult hepatitis C virus infection is defined by the presence of hepatitis C virus-RNA in liver but with undetectable anti-hepatitis C virus and serum viral RNA.

AIM

To study the response to anti-viral therapy in occult hepatitis C virus infection to assess the pathogenic effect of occult hepatitis C virus.

METHODS

Ten patients with occult hepatitis C virus infection were treated with pegylated-interferon plus ribavirin for 24 weeks and were followed-up 24 weeks after therapy. All patients had abnormal alanine aminotransferase, hepatitis C virus-RNA positive in peripheral blood mononuclear cells and liver necroinflammation.

RESULTS

At the end of treatment and follow-up, the percentage of patients with normal alanine aminotransferase was 80% (95% CI: 48-96%) and 60% (95% CI: 31-84%) respectively, and hepatitis C virus-RNA in peripheral blood mononuclear cells was negative in 80% (95% CI: 48-96%) and 70% (95% CI: 40-90%) cases. At the end of follow-up sustained response was observed in 30% (95% CI: 11-61%) of cases. Five patients underwent a second liver biopsy. In all cases, liver hepatitis C virus-RNA persisted, although hepatitis C virus-RNA load was significantly lower (3.2 x 10(4) +/- 5.1 x 10(4) copies/microg RNA) than in the basal biopsy (2.4 x 10(5) +/- 3.8 x 10(5) copies/microg RNA); (P = 0.043). Necroinflammation and fibrosis decreased in three cases.

CONCLUSION

The biochemical, virological and histological response to therapy achieved in patients with occult hepatitis C virus infection demonstrates the pathologic effects of occult hepatitis C virus.

Long-term follow-up of chronic hepatitis C patients with sustained virological response to various forms of interferon-based anti-viral therapy

BACKGROUND

Combination anti-viral therapy achieves a sustained virological response (defined as HCV-RNA negativity 6 months after the end of therapy) of 56% of patients with chronic hepatitis C. Little is known about long-term durability of HCV-RNA negativity in patient treated with pegylated interferon.

AIM

To evaluate the durability of virologic response in patients with sustained virological response to anti-viral therapy treated at our centre.

METHODS

A total of 187 sustained virological responses (50% genotype 1, 42% genotype 2 or 3 and 8% genotype 4; 20% with cirrhosis) with a follow-up of >12 months post-therapy were studied. Twelve patients received monotherapy with interferon-alpha2a or -2b. One hundred and seventy-five received combination therapy with ribavirin and standard interferon-alpha (n = 73) or pegylated interferon-alpha2a or 2b (n = 102). Qualitative serum HCV-RNA was tested by COBAS AMPLICOR HCV test, v2.0.

RESULTS

Median follow-up time was 29 months (range 12-172). Recurrence of HCV infection was not observed in any of the 187 sustained virological responders. Alanine aminotransferase values were normal in 90% and two patients showed minimal elevation of alpha-fetoprotein levels.

CONCLUSIONS

No recurrence of HCV infection was seen in any patient. Thus, long-term prognosis in chronic hepatitis C patients with a sustained virological response to therapy with pegylated interferon +/- ribavirin is promising, but long-term studies need to continue.

Therapy of hepatitis C: from empiricism to eradication

The complications of chronic hepatitis C virus infection can be prevented by antiviral therapy. The initial choice of interferon alfa and, subsequently, ribavirin as potential treatments for chronic hepatitis C was empirical. Nevertheless, the combination of pegylated interferon alfa and ribavirin has become the standard treatment of chronic hepatitis C. Since the advent of interferon-based therapy, enormous progress has been made in understanding the mechanisms of treatment efficacy and failure, and in everyday patient management. The principal advances are: a better understanding of hepatitis C virus steady-state kinetics and the antiviral mechanisms of interferon and ribavirin; easier treatment decisions thanks to novel assays to assess liver disease severity and the virological characteristics of infection; a better use of virological tests to tailor therapy; a better management of adverse effects; a better understanding of virological treatment failure; and a better management of "special" populations, including patients with decompensated cirrhosis and end-stage liver disease, liver transplant recipients, hemodialysis patients and renal transplant recipients, human immunodeficiency virus-coinfected patients, intravenous drug users and patients on opiate replacement therapy, or virological non responders to previous therapies. Steady-state HCV kinetics offers several potential targets for new drugs. These targets should ideally be hit simultaneously in order to achieve viral eradication within a reasonable time frame. Future drugs for HCV infection will belong to four main categories, including new interferons, alternatives to ribavirin, specific HCV inhibitors, and immune modulators. New treatments and vaccines might make it possible to eradicate HCV in the future.

Hepatitis C: cost of illness and considerations for the economic evaluation of antiviral therapies

Chronic hepatitis C virus (HCV) infection affects 170 million individuals worldwide. As it is detected incidentally through the evaluation of liver function tests or at the time of blood donor testing, it is usually clinically silent until the advanced stages of liver disease have occurred, when treatment is less effective and shortages of donor liver organs limit the therapeutic options. Combination therapy with ribavirin and pegylated interferon has resulted in sustained viral negative response rates of 54-61%. Because treatment is expensive and not uniformly effective, and because not all chronically infected patients will develop complications, concerns have arisen regarding the cost effectiveness of combination therapy. This paper reviews the public health and individual implications of HCV infections. Because of the latency of infection, numerous country-specific population analyses suggest that HCV will cause an increasing number of liver-related deaths over the next 10 years, despite the dramatic drop in incidence over the past 10-15 years. These deaths will be related to prevalent HCV infection from transfusion and injection drug use prior to identification of the virus and availability of screening tests in the late 1980s and early 1990s. HCV can reduce life expectancy and impair quality of life, yet not all patients will develop progressive liver disease, and antiviral treatment may have associated adverse effects. Finally, to assess the value of antiviral drugs for HCV infection, this paper reviews studies examining the costs of antiviral drugs and of the disease itself along with response to antiviral therapy and the cost effectiveness of antiviral therapy. Although antiviral therapy appears to be expensive, when also considering the likelihood of sustained viral response to therapy, and the cost savings, quality-of-life improvement and prolongation of life expectancy from the prevention of HCV complications, antiviral treatment for HCV appears to be cost effective when compared with other well accepted medical interventions.

Antiviral therapy after non-surgical tumor ablation in patients with hepatocellular carcinoma associated with hepatitis C virus

BACKGROUND

Antiviral therapy for chronic hepatitis C virus (HCV) infection has led to a reduction in the incidence of hepatocellular carcinoma (HCC). The purpose of the present paper was to assess whether antiviral therapy might suppress tumor recurrence and influence overall survival in patients with HCV-related HCC who had complete ablation of nodules by non-surgical treatments.

METHODS

Twenty patients with three or fewer nodules of HCV-related HCC who were treated with percutaneous tumor ablation and/or transcatheter arterial embolization received combined interferon (IFN; 3 or 5 million units of IFN alpha-2b thrice weekly) plus ribavirin (1000-1200 mg per day) therapy for 24-48 weeks after complete ablation of lesions. During the same period, an additional 40 age- and sex-matched control patients with similar characteristics of tumors (sizes, numbers and treatment modalities) and severity of liver disease were recruited from the HCC database. Both recurrence-free survival and actuarial survival were evaluated.

RESULTS

Of the 20 patients, 16 completed therapy and 10 showed a sustained response with normalization of alanine aminotransferase and negative HCV-RNA at 6 months after therapy completion. Due to severe side-effects experienced by Child B patients, who mostly discontinued antiviral therapy, clinical outcome was analyzed in the Child A treated (n = 16) and control (n = 33) patients. There was no significant difference in the incidence of local recurrence in sustained responders compared with non-responders or control patients (P = 0.174, 0.1284, respectively); but the second recurrence-free interval in the sustained responders was significantly longer than that of non-responders and the control group (P = 0.0141, 0.0243, respectively). Survival in sustained responders was better than in non-responders and control patients (P = 0.0691, 0.0554, respectively).

CONCLUSIONS

These results indicate that successful antiviral therapy after non-surgical tumor ablation for HCV-related HCC may lower tumor recurrence rate and prolong survival.

Mechanism of action of interferon and ribavirin in treatment of hepatitis C

Since the identification of the hepatitis C virus, great strides have been made in the development of an antiviral therapy. As a crucial mediator of the innate antiviral immune response, interferon-alpha (IFN-alpha) was a natural choice for treatment. Whereas treatment with IFN-alpha alone achieved only modest success, the addition of the broad-spectrum antiviral agent ribavirin greatly improved responses. However, half of the infected individuals with chronic disease do not achieve sustained clearance of hepatitis C virus. To optimize current therapeutic strategies and to develop new therapies, a better understanding of the mechanism of action of IFN and ribavirin will be essential.

Using competence network collaboration and decision-analytic modeling to assess the cost-effectiveness of interferon alpha-2b plus ribavirin as initial treatment of chronic hepatitis C in Germany

The objective of this study was to translate and apply a decision-analytic model for chronic hepatitis C (CHC) to the German health care context using competence network collaboration. The German Hepatitis C Model (GEHMO) competence network used a systematic multistep approach to identify and transfer a high quality Markov model for CHC to the German health care context. GEHMO was used to project lifetime clinical and economic outcomes and to determine the cost-effectiveness of initial antiviral therapy with interferon a-2b plus ribavirin from a societal perspective. In 40-year-old patients combination therapy for 24 and 48 weeks increased life expectancy by 1.6 and 2.3 years, respectively, compared with interferon alone for 48 weeks. The discounted incremental cost-utility ratios (ICUR) for combination therapy were euro 5,500 per quality-adjusted life-year gained (QALY) for 24 weeks and euro 6,800/QALY for 48 weeks of treatment. ICUR was euro 9,800/QALY for moving from 24 to 48 weeks of treatment. Combination therapy remained cost-effective in sensitivity analyses. In conclusion, combination therapy with interferon alpha-2b and ribavirin is effective and cost-effective compared with other well-accepted medical treatments. Competence network collaboration and decision modeling provide a useful and efficient approach to combine evidence from international studies with country-specific parameters.

Routine hepatitis C virus screening in pregnancy: a cost-effectiveness analysis

OBJECTIVE

The purpose of this study was to determine whether routine hepatitis C virus screening in pregnancy is cost-effective.

STUDY DESIGN

A decision tree with Markov analysis was developed to compare 3 approaches to asymptomatic hepatitis C virus infection in low-risk pregnant women: (1) no hepatitis C virus screening, (2) hepatitis C virus screening and subsequent treatment for progressive disease, and (3) hepatitis C virus screening, subsequent treatment for progressive disease, and elective cesarean delivery to avert perinatal transmission. Lifetime costs and quality-adjusted life years were evaluated for mother and child.

RESULTS

In our base case, hepatitis C virus screening and subsequent treatment of progressive disease was dominated (more costly and less effective) by no screening, with an incremental cost of 108 US dollars and a decreased incremental effectiveness of 0.00011 quality-adjusted life years. When compared with no screening, the marginal cost and effectiveness of screening, treatment, and cesarean delivery was 117 US dollars and 0.00010 quality-adjusted life years, respectively, which yields a cost-effectiveness ratio of 1,170,000 US dollars per quality-adjusted life year.

CONCLUSION

The screening of asymptomatic pregnant women for hepatitis C virus infection is not cost-effective.

Biological and clinical basis for molecular studies of interferons

The cytokine family of interferons (IFNs) has multiple functions, including antiviral, anti-tumor, and immunomodulatory effects and regulation of cell differentiation. The multiple functions of the IFN system are thought to be an innate defense against microbes and foreign substances. The IFN system consists first of cells that produce IFNs in response to viral infection or other foreign stimuli and second of cells that establish the antiviral state in response to IFNs. This process of innate immunity involves multiple signaling mechanisms and activation of various host genes. Viruses have evolved to develop mechanisms that circumvent this system. IFNs have also been used clinically in the treatment of viral diseases. Improved treatments will be possible with better understanding of the IFN system and its interactions with viral factors. In addition, IFNs have direct and indirect effects on tumor cell proliferation, effector leukocytes and on apoptosis and have been used in the treatment of some cancers. Improved knowledge of how IFNs affect tumors and the mechanism that lead to a lack of response to IFNs would help the development of better IFN treatments for malignancies.

Persistence of hepatitis C virus in patients successfully treated for chronic hepatitis C

It is unclear whether the current antiviral treatment for chronic hepatitis C virus (HCV) infection results in complete elimination of the virus, or whether small quantities of virus persist. Our study group comprised 17 patients with chronic HCV who had sustained virological response (SVR) after interferon/ribavirin treatment. Serum and peripheral blood mononudear cells were collected 2 to 3 times at 3- to 6-month intervals starting 40 to 109 months (mean, 64.2 +/- 18.5 months) after the end of therapy. In addition, lymphocyte and macrophage cultures were established at each point. In 11 patients, frozen liver tissue samples were available from follow-up biopsies performed 41 to 98 months (mean, 63.6 +/- 16.7 months) after therapy. Presence of HCV RNA was determined by sensitive reverse-transcriptase polymerase chain reaction, and concentration of positive and negative strands was determined by a novel quantitative real-time reverse transcriptase polymerase chain reaction. Only 2 of 17 patients remained consistently HCV RNA negative in all analyzed compartments. HCV RNA was detected in macrophages from 11 patients (65%) and in lymphocytes from 7 patients (41%). Viral sequences were also detected in 3 of 11 livers and in sera from 4 patients. Viral replicative forms were found in lymphocytes from 2 and in macrophages from 4 patients. In conclusion, our results suggest that in patients with SVR after therapy, small quantities of HCV RNA may persist in liver or macrophages and lymphocytes for up to 9 years. This continuous viral presence could result in persistence of humoral and cellular immunity for many years after therapy and could present a potential risk for infection reactivation.

Use of the MagNA pure LC automated nucleic acid extraction system followed by real-time reverse transcription-PCR for ultrasensitive quantitation of hepatitis C virus RNA

Hepatitis C virus (HCV) infection is an increasing health problem worldwide. Quantitative assays for HCV viral load are valuable in predicting response to therapy and for following treatment efficacy. Unfortunately, most quantitative tests for HCV RNA are limited by poor sensitivity. We have developed a convenient, highly sensitive real-time reverse transcription-PCR assay for HCV RNA. The assay amplifies a portion of the 5' untranslated region of HCV, which is then quantitated using the TaqMan 7700 detection system. Extraction of viral RNA for our assay is fully automated with the MagNA Pure LC extraction system (Roche). Our assay has a 100% detection rate for samples containing 50 IU of HCV RNA/ml and is linear up to viral loads of at least 10(9) IU/ml. The assay detects genotypes 1a, 2a, and 3a with equal efficiency. Quantitative results by our assay correlate well with HCV viral load as determined by the Bayer VERSANT HCV RNA 3.0 bDNA assay. In clinical use, our assay is highly reproducible, with high and low control specimens showing a coefficient of variation for the logarithmic result of 2.8 and 7.0%, respectively. The combination of reproducibility, extreme sensitivity, and ease of performance makes this assay an attractive option for routine HCV viral load testing.

Hepatitis C virus infection and the brain

While HCV was initially believed to uniformly cause liver inflammation with the consequence of liver cirrhosis in most of the infected patients, prospective studies have shown a much lower than expected rate of cirrhosis in patients infected for more than 20 years. However, a new problem associated with hepatitis C virus infection is emerging. This is the development of sometimes disabling fatigue. While many other viruses of the flaviviridae cause encephalitis, the most closely related virus to HCV in humans, the GB Virus C seems not to be associated with fatigue. Thus the mechanism for the development of fatigue in HCV infection seems specific for HCV. Delineating the mechanism will be a first step to develop treatment option for this currently untreatable impairment.

Long-term clinical and virological outcomes of chronic hepatitis C after successful interferon therapy

Clinical relevance of occult hepatitis C virus (HCV) and/or hepatitis B virus (HBV) infection(s) remains uncertain years after interferon (IFN) therapy for chronic hepatitis C. By 1993, 38 sustained virological responders (SVRs) showing HCV RNA clearance at 6 months post-treatment and 37 biochemical responders (BRs) with end-of-treatment alanine aminotransferase (ALT) normalization and subsequent 6-month stabilization within 2 x the upper limit of normal (ULN) were enrolled. They were monitored for 4.4-12 years (median 6.8), then 15 SVRs and 15 BRs underwent paired liver biopsies. Biopsy samples were tested for positive and negative HCV RNA strands, and HBV DNA surface and X sequences. All SVRs showed sustained serum HCV RNA clearance during follow-up, but hepatocellular carcinoma (HCC) developed in 4 (11%) SVRs. On paired liver biopsies, histological improvement was significant, but mild inflammation persisted in 87% of SVRs. Nonetheless, no HCV RNA sequence was amplified from liver tissues, and HBV DNA sequences were found in only one SVR. As for BRs, biochemical flare-up of >2 x ULN occurred at a 5-year risk of 41% (95% CI 24.7-56.4). The event was unpredictable but controllable by retreatment in 70%. Liver tissues after follow-up contained positive and negative HCV RNA strands, but no HBV DNA sequence was amplified. These results suggest that SVRs, albeit free of occult HCV and/or HBV infection(s) over a decade, retain mild liver inflammation and the risk of HCC. Occult HBV was also shown uninvolved in flare-up during follow-up of BRs.

Regression of liver fibrosis in cases of chronic liver disease type C: quantitative evaluation by using computed image analysis

OBJECT

It was reported that the liver fibrosis is reduced in patients with chronic liver disease type C after eradication of HCV. Degree of fibrosis was expressed by the classical fibrosis scoring system (F0-F4) at present. However a change of subtle reduction of fibrosis cannot be expressed in its fibrosis score and thus we measured an area of fibrosis and compared detailed change of the fibrosis area in paired liver biopsy.

METHODS

For quantitative assessment of liver fibrosis, we measured an area of fibrosis using computed digital image analysis and pursued the rate of a fibrosis area for whole biopsied liver tissue of 25 patients with HCV infection (20 complete response patients to IFN therapy who showed viral eradication: CR and 5 non-treated ones with IFN but had conservative therapy: CT).

RESULTS

In CR group, fibrosis rate was 7.2 +/- 1.5% before therapy, 2.7 +/- 0.5% after the therapy and they were significantly regressed. In CT group, fibrosis rate was 8.4 +/- 4.3% at the first biopsy, 15.9 +/- 7.7% at the second biopsy.

CONCLUSIONS

Regression of liver fibrosis could be confirmed in patients with virologic response to IFN even in patients with liver cirrhosis. Our quantitative evaluation provided information superior to that obtained by the classical fibrosis staging score system.

Nonresponders to hepatitis C virus antiviral therapy: pegylated interferons and beyond

Nonresponders to prior antiviral therapy are a heterogeneous but growing population of hepatitis C patients in the United States. The likelihood of response to retreatment with pegylated interferon(PEG IFN) and ribavirin (RBV) is largely dependent upon hepatitis C virus genotype and the type, duration, and response to prior antiviral therapy. Investigational trials with clinical and histological end points for nonresponders with advanced fibrosis including maintenance PEG IFN and other antifibrotic agents should be completed in the next 5 years. In the interim, decisions regarding retreatment with PEG IFN and RBV should be made on a case-by-case basis after considering the tolerability of prior treatment, the severity of underlying liver disease, and the anticipated likelihood of response.

Hepatitis C treatment update

Hepatitis C is a leading cause of chronic liver disease in the United States, and the prevalence of hepatitis C-associated complications is increasing. Therapy with pegylated interferon and ribavirin has become the standard of care for chronic hepatitis C; the sustained response rate for treatment-naïve patients is about 55%. If certain patients fail to achieve a 12-week treatment milestone, an early virologic response, they may be taken off treatment early, potentially sparing them from unnecessary medication. Adherence is critical for treatment success. Although side effects continue to be a hindrance to the success of therapy, agents such as growth factors and antidepressants may help patients to maintain medication dosing and complete treatment. Therapy is generally recommended for those in whom the infection is most likely to progress to cirrhosis; however, there is continued debate about the suitability of certain patients for treatment, including those with persistently normal aminotransferase levels or acute hepatitis C and nonresponders to conventional treatment. Four broad groups of investigational therapeutic agents appear promising for future therapy: modified interferons and ribavirins, immunomodulators, viral life-cycle targets, and antifibrotic agents.

Epidemiology, Diagnosis, and Treatment of Chronic Hepatitis C

The hepatitis C virus (HCV) is a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma and is also a common indication for liver transplantation. Interferon alfa monotherapy leads to a sustained virologic response in only 10% to 15% of HCV-infected patients. The sustained virologic response rates can be increased to approximately 40% with interferon alfa-2b and ribavirin combination therapy for up to 48 weeks. However, recent clinical trials demonstrated that pegylated interferon in combination with ribavirin can improve the response rates even further, with more than 50% of patients having a sustained virologic response to treatment. Although new therapies are emerging, significant progress must be made to reduce the morbidity and mortality from HCV infection.

Peginterferon alfa-2a: A review of approved and investigational uses

BACKGROUND

In October 2002, the US Food and Drug Administration approved peginterferon alfa-2a for the management of chronic hepatitis C virus (HCV) infection. The addition of polyethylene glycol (PEG) moiety to the interferon (IFN) molecule results in a product with altered pharmacokinetic properties.

OBJECTIVE

The aim of this article is to review the pharmacology, medications interactions, adverse events (AEs), and approved or investigational uses of PEG-IFN alfa-2a for viral hepatitis and oncologic conditions.

METHODS

Relevant articles were identified through searches of MEDLINE (1980-July 2003) and EMBASE (1980-July 2003). Search terms included, but were not limited to, peginterferon alfa-2a, pharmacokinetics, pharmacology, pharmacodynamics, and therapeutic use, as well as terms for specific disease states and AEs. Further publications were identified from citations of resulting papers.

RESULTS

Pegylation of IFN alfa-2a results in major changes in the pharmacokinetics of the product. Absorption is prolonged and serum concentrations are sustained over the dosing regimen. PEG-IFN alfa-2a has been shown to be more effective with or without ribavirin (RBV), in the management of treatment-naive patients with chronic HCV infection, than unmodified IFN alfa-2a with or without RBV. Results in other disease states are still preliminary. AEs are similar, in incidence and severity, to those occurring with unmodified IFN. They include earlier hematologic symptoms and fewer influenza-like symptoms. Drug-drug interactions are the same as those occurring with the unmodified IFN product.

CONCLUSIONS

The pharmacokinetic profile of IFN alfa-2a is improved by pegylation, which enables less frequent administration and results in improved efficacy with a similar side-effect profile. Combination of PEG-IFN alfa-2a with RBV is associated with a greater chance of achieving a sustained virologic response in treatment-naive patients with chronic HCV, compared with unmodified IFN alfa-2a/RBV combinations. Documentation of efficacy in other conditions awaits results of controlled clinical trials.

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.

Hepatitis C Infection: A Clinical Review

Nearly three million persons in the United States are viremic with hepatitis C (HCV). Despite a decreasing incidence of HCV in this country, the prevalence of HCV-related chronic liver disease is increasing. Most infections in the United States are acquired by intravenous drug use. The chronicity rate of HCV is high, reaching 85% in some populations, and the risk of progression to advanced liver disease is as high as 20% within twenty years of infection. Host factors like alcohol use accelerate the rate of progression. The enzyme immunoassay is the preferred initial test for diagnosis; the third generation assay has greater than a 99% specificity in immunocompetent patients. Barring contraindications, the standard of care for treatment of chronic HCV has become pegylated interferon and ribavirin. With this therapy, the cure rate for treatment-naïve patients is about 55%, but rates are higher in certain groups. Common side effects of therapy include neuropsychiatric symptoms, influenza-like symptoms and hematological abnormalities.

Peripheral CD4(+)CD8(+) T cells are differentiated effector memory cells with antiviral functions

Although an increased frequency of CD4(+)CD8(+) T cells has been observed in the peripheral blood during viral infections, their role, function, and biologic significance are still poorly understood. Here we demonstrate that the circulating CD4(+)CD8(+) T-cell population contains mature effector memory lymphocytes specific for antigens of multiple past, latent, and high-level persistent viral infections. Upon in vitro antigenic challenge, a higher frequency of CD4(+)CD8(+) than single-positive cells displayed a T helper 1/T cytotoxic 1 (Th1/Tc1) cytokine profile and proliferated. Ex vivo, more double-positive than single-positive cells exhibited a differentiated phenotype. Accordingly, their lower T-cell receptor excision circles (TREC) content and shorter telomeres proved they had divided more frequently than single-positive cells. Consistent with expression of the tissue-homing marker CXCR3, CD4(+)CD8(+) T cells were demonstrated in situ at the site of persistent viral infection (ie, in the liver during chronic hepatitis C). Finally, a prospective analysis of hepatitis C virus (HCV) infection in a chimpanzee, the only animal model for HCV infection, showed a close correlation between the frequency of activated CD4(+)CD8(+) T cells and viral kinetics. Collectively, these findings demonstrate that peripheral CD4(+)CD8(+) T cells take part in the adaptive immune response against infectious pathogens and broaden the perception of the T-cell populations involved in antiviral immune responses.

In vitro inhibition of Chikungunya and Semliki Forest viruses replication by antiviral compounds: synergistic effect of interferon-alpha and ribavirin combination

Chikungunya virus (CHIKV) and Semliki Forest virus (SFV) were used in our laboratory to screen active antiviral compounds against viruses of the Alphavirus genus. Antiviral activity was estimated by the reduction of the cytopathic effect of each alphavirus on infected Vero cells and by virus titer reduction. Cytotoxicity was evaluated by determining the inhibition of Trypan blue exclusion in confluent cell cultures and by the evaluation of the inhibitory effect on cell growth. With CHIKV and SFV, the selectivity indices of human recombinant interferon-alpha and iota-carrageenan were much higher than that of ribavirin, which has been previously investigated for its inhibitory effect on alphavirus infections. Compared to ribavirin, 6-azauridine was more effective against CHIKV and showed a similar antiviral activity against SFV. IFN-alpha2b, glycyrrhizin, 6-azauridine, and ribavirin caused a concentration-dependent reduction in the virus yield with CHIKV and SFV. Moreover, the combination of IFN-alpha2b and ribavirin had a subsynergistic antiviral effect on these two alphaviruses and should be evaluated for the treatment of these infections.

Update on chronic hepatitis C

Strategies for the diagnosis and treatment of chronic hepatitis C continue to evolve. Liver biopsy is now used selectively rather than routinely, and the combination peginterferon plus ribavirin is the treatment of choice for the majority of patients.