Treatment of hepatitis C: how will we use viral kinetics, response-guided therapy? Curr Gastroenterol Rep. 2013;15:309. [PMID: 23314805 DOI: 10.1007/s11894-012-0309-x]

Standard Versus Extended Duration Direct-Acting Antiviral Therapy in Hepatitis C Patients With Slow Response to Treatment

BACKGROUND

Response-guided hepatitis C therapy was standard with interferon-based regimens but is not used for direct-acting antivirals (DAAs). Week 4 viral kinetics may predict sustained virological response (SVR) with DAAs, but it is unclear whether extending therapy in slow responders affects outcomes.

OBJECTIVES

The primary objective was to compare SVR rates between traditional and extended duration groups. Secondary objectives were to compare SVR rates among subgroups and to determine factors associated with SVR.

METHODS

This institutional review board-approved, retrospective, single-center study identified patients with chronic hepatitis C virus (HCV) infection with detectable week 4 HCV RNA who were treated with DAAs. Patients were excluded for early discontinuation, treatment regimen not recommended first-line, or missing HCV RNA labs. Patients were stratified into traditional and extended duration groups. The primary end point was SVR. Secondary end points included factors associated with SVR and rationale for extension of therapy duration.

RESULTS

A total of 363 patients were included; 58 (16%) received extended therapy. Patients were primarily genotype 1a (70%) and treatment naïve (80%). More than half had advanced fibrosis or cirrhosis. SVR12 rates were 100% in the extended duration group and 96.7% in the traditional duration group (P = 0.37). There were no associations with SVR and prespecified patient-specific factors. Sample size was limited.

CONCLUSION AND RELEVANCE

Based on these findings, a recommendation for extension of therapy cannot be made for patients with detectable HCV RNA at week 4 of treatment at this time. Cost analyses may help guide recommendations to re-treat rare failures versus extend therapy in all slow responders.

Time to Detection of Hepatitis C Virus Infection With the Xpert HCV Viral Load Fingerstick Point-of-Care Assay: Facilitating a More Rapid Time to Diagnosis

Background

Xpert HCV Viral Load Fingerstick assay (Xpert HCV VL FS) is a point-of-care test quantifying HCV RNA in <1 hour, enabling same-visit diagnosis and treatment.

Methods

This study evaluated time to HCV RNA detection using the Xpert HCV VL FS assay. Fingerstick whole-blood samples were collected from participants in an observational cohort in Australia.

Results

In May 2018–2019, 1468 participants were enrolled, 1426 had Xpert HCV VL FS testing performed, and 1386 had a valid result. HCV RNA was detected in 23% (325/1386). Among people with undetectable HCV RNA (n = 1061), median time to result was 57 minutes. Among people with detectable HCV RNA (n = 325), median time to HCV RNA detection was 32 minutes and 80% (261/325) had a detectable HCV RNA result in ≤40 minutes. Median time to HCV RNA detection was dependent on HCV RNA level.

Conclusions

A quicker HCV diagnosis could be achieved by monitoring the time when HCV RNA is first detected with the Xpert HCV VL FS test, rather than HCV RNA quantification, although the current platform does not allow for this. These findings could facilitate new strategies to reduce waiting times for an HCV diagnosis and improve linkage to treatment.

Short article: Viral dynamics among hepatitis C virus chronic infected patients during direct-acting antiviral agents therapy: impact for monitoring and optimizing treatment duration

OBJECTIVES

Direct-acting antiviral agents (DAAs) have provided an ultimate treatment duration of 12 weeks for most hepatitis C virus (HCV)-infected patients. The opportunity to reduce treatment duration to 6 or 8 weeks is being evaluated. Here, the HCV viral dynamics at short times during HCV therapies and its implications for monitoring and optimizing treatment duration have been assessed.

PATIENTS AND METHODS

HCV chronic infected patients who began HCV therapy (March 2014 to June 2015) at a reference hospital of the Northwest of Spain were selected. HCV-RNA was quantified at different short time points during HCV therapy using Abbott RealTime HCV assay. Epidemiological, clinical, and virological data were recorded.

RESULTS

Eleven HCV-infected patients were included; 90.9% had cirrhosis (>12.5 kPa) and 72.7% were treatment-experienced. HCV genotype 1b was the most prevalent (72.7%). All of the combinations were pegylated interferon-free and all included ribavirin. The median HCV-RNA (log IU/ml) at baseline was 5.8 (5.4-6.1); the decline between baseline and day 3, weeks 4, 8, and 12 was 3.2, 4.8, 5.1, and 5.6, respectively. Fewer than 50% of patients achieved undetectable viral load at weeks 4 and 8; however, all patients achieved a sustained virologic response at 12 weeks.

CONCLUSION

Rapid and high HCV-RNA decline was observed among HCV-infected patients under DAA-based regimens, especially for those without cirrhosis. Despite low rates of patients with undetectable HCV-RNA at weeks 4 and 8, all achieved a sustained virologic response at 12 weeks. These findings suggest that the time points to monitor HCV-RNA during DAA therapies and the treatment duration need to be optimized.

Interferon-free, direct-acting antiviral therapy for chronic hepatitis C

The treatment environment for chronic hepatitis C has undergone a revolution, particularly in genotype 1. Gone are interferon-based therapy and its associated tolerability challenges, inadequate response rates and numerous baseline factors that affect response to therapy. New and emerging treatment regimens employ all-oral combinations of direct-acting antiviral agents, and results of clinical trials suggest that these regimens routinely achieve cure rates >90%, even in patients who failed prior interferon-based triple therapy. In 2015, three all-oral FDA-approved regiments will be available for genotype 1 (sofosbuvir /ledipasvir, sofosbuvir/simeprevir, and paritaprevir/r/ombitasvir/dasabuvir). Furthermore, new treatment combinations appear to be more tolerable and require shorter duration of therapy. We provide an overview of the classes of direct-acting antiviral agents (DAAs), the clinical factors affecting their integration into combination therapies and recent findings from trials of such combination therapies in patients with genotype 1 HCV infection.

Twenty-five years of type I interferon-based treatment: a critical analysis of its therapeutic use

The clinical exploitation of type I interferon (IFN) as an antiviral and antineoplastic agent is based on the properties originally attributed to this cytokine family, with schedules reflecting only their antiviral and antiproliferative activities. Nevertheless, type I IFN has emerged as a central activator of the innate immunity. As current schedules of treatment for chronic hepatitis C and for hematological and solid tumors, based on the continuous administration of recombinant type I IFN or pegylated formulations, disregard viral resistance, host genetic variants predicting treatment outcome and mechanisms of refractoriness, new administration schedules, the combination of type I IFN with new drugs and the increased monitoring of patients' susceptibility to type I IFN are expected to provide a new life to this valuable cytokine.

BMI, male sex and IL28B genotype associated with persistently high hepatitis C virus RNA levels among chronically infected drug users up to 23 years following seroconversion

The natural course of serum HCV RNA levels during chronic infection remains unclear. We investigated HCV RNA levels and factors associated with HCV RNA levels for the entire course from HCV seroconversion. We measured HCV RNA levels of 54 HCV seroconverters from the Amsterdam Cohort Studies among drug users at yearly intervals up to 23 years using bDNA (VERSANT 3.0, lower limit of detection 615 IU/mL). Samples below the cut-off of the assay were tested by TMA (Siemens VERSANT, detection limit 5 IU/mL). We used a latent class linear mixed model to examine the HCV RNA patterns and factors associated with HCV RNA levels. The median follow-up time was 10.8 years (IQR 6.5-14.9). We found two distinct HCV RNA patterns characterized by 45/54 cases and 9/54 cases. In multivariable analyses, HCV RNA levels were 0.41 log(10) IU/mL (95% confidence interval (CI) 0.06-0.75) higher for males as compared to females. Individuals with the IL28B CC genotype had 0.40 log(10) IU/mL (95% 0.08-0.73) higher HCV RNA levels than individuals with IL28B CT/TT genotypes. Body mass index (BMI) was associated with higher HCV RNA levels, 0.055 log(10) IU/mL per BMI point (95% CI 0.027-0.083). In this unique study, which examines the HCV RNA patterns over an extended period and following seroconversion, male sex, IL28B CC genotype and BMI were independently associated with higher average HCV RNA levels. These results contribute to defining the natural history of HCV infection and could play an important part in clinical decision-making.

Understanding early serum hepatitis D virus and hepatitis B surface antigen kinetics during pegylated interferon-alpha therapy via mathematical modeling

There is little information on the early kinetics of hepatitis delta virus (HDV) and hepatitis B surface antigen (HBsAg) during interferon-α therapy. Here a mathematical model was developed and fitted to frequent HDV and HBsAg kinetic data from 10 patients during the first 28 weeks of pegylated-interferon-α2a (peg-IFN) therapy. Three patients achieved a complete virological response (CVR), defined as undetectable HDV 6 months after treatment stopped with loss of HBsAg and anti-HBsAg seroconversion. After initiation of therapy, a median delay of 9 days (interquartile range [IQR]: 5-15) was observed with no significant changes in HDV level. Thereafter, HDV declined in a biphasic manner, where a rapid first phase lasting for 25 days (IQR: 23-58) was followed by a slower or plateau second phase. The model predicts that the main effect of peg-IFN is to reduce HDV production/release with a median effectiveness of 96% (IQR: 93-99.8). Median serum HDV half-life (t1/2 ) was estimated as 2.9 days (IQR: 1.5-5.3) corresponding to a pretreatment production and clearance of about 10(10) (IQR: 10(9.7) -10(10.7) ) virions/day. None of the patients with flat second phase in HDV achieved CVR. HBsAg kinetics of decline paralleled the second phase of HDV decline consistent with HBsAg-productive-infected cells being the main source of production of HDV, with a median t1/2 of 135 days (IQR: 20-460). The interferon lambda-3 polymorphism (rs12979860) was not associated with kinetic parameters.

CONCLUSION

Modeling results provide insights into HDV-host dynamics, the relationship between serum HBsAg levels and HBsAg-infected cells, IFN's mode of action, and its effectiveness. The observation that a flat second phase in HDV and HBsAg kinetics was associated with failure to achieve CVR provides the basis to develop early stopping rules during peg-IFN treatment in HDV-infected patients.

Hepatitis C virus in the new era: Perspectives in epidemiology, prevention, diagnostics and predictors of response to therapy

Despite the great successes achieved in the fields of virology and diagnostics, several difficulties affect improvements in hepatitis C virus (HCV) infection control and eradication in the new era. New HCV infections still occur, especially in some of the poorest regions of the world, where HCV is endemic and long-term sequelae have a growing economic and health burden. An HCV vaccine is still no available, despite years of researches and discoveries about the natural history of infection and host-virus interactions: several HCV vaccine candidates have been developed in the last years, targeting different HCV antigens or using alternative delivery systems, but viral variability and adaption ability constitute major challenges for vaccine development. Many new antiviral drugs for HCV therapy are in preclinical or early clinical development, but different limitations affect treatment validity. Treatment predictors are important tools, as they provide some guidance for the management of therapy in patients with chronic HCV infection: in particular, the role of host genomics in HCV infection outcomes in the new era of direct-acting antivirals may evolve for new therapeutic targets, representing a chance for modulated and personalized treatment management, when also very potent therapies will be available. In the present review we discuss the most recent data about HCV epidemiology, the new perspectives for the prevention of HCV infection and the most recent evidence regarding HCV diagnosis, therapy and predictors of response to it.

Response-guided therapy in patients with genotype 1 hepatitis C virus: current status and future prospects

On-treatment responses to antiviral therapy are used to determine duration of therapy in patients being treated for genotype 1 hepatitis C virus infection. Such use of response-guided therapy has successfully reduced exposure of patients to the side-effects of pegylated interferon and ribavirin without jeopardizing overall treatment success. Response-guided therapy is an integral part of treatment using the current standard treatments involving the direct-acting antiviral (DAA) agents--boceprevir or telaprevir--combined with pegylated interferon/ribavirin. Improvements in our understanding of the kinetics of viral load during antiviral therapy have shown us that more potent suppression of viral replication increases the rate of viral eradication, providing impetus for the development of more potent DAAs. Emerging results from clinical trials of these agents--including trials of interferon-free DAA combinations--suggest that very high rates of viral eradication are achievable, even in patients who failed to respond to previous courses of interferon-based therapy. Furthermore, because of these high rates of treatment success, on-treatment assessment of viral response may become unnecessary. The field of hepatitis C virus therapy is evolving rapidly and current trends indicate that the era of simple treatment regimens with high rates of success and good tolerability are near.