[Position paper of the Catalan Society of Gastroenterology: treatment of Genotype 1 Chronic Hepatitis C Virus with Triple Therapy]

Comorbidity, concomitant medication, use of resources and healthcare costs associated with chronic hepatitis C virus carriers in Spain

OBJECTIVES

To assess the comorbidity, concomitant medications, healthcare resource use and healthcare costs of chronic hepatitis C virus patients in the Spanish population.

PATIENTS AND METHODS

Retrospective, observational, non-interventional study. Patients included were≥18 years of age who accessed medical care between 2010-2013. Patients were divided into 2 groups based on the presence or absence of liver cirrhosis. The follow-up period was 12 months. Main assessment criteria included general comorbidity level (determined by the resource utilisation band score) and prevalence of specific comorbidities, concomitant medications, healthcare resource use and healthcare costs. Statistical analysis was performed using regression models and ANCOVA, P<.05.

RESULTS

One thousand fifty-five patients were enrolled, the mean age was 57.9 years and 55.5% were male. A percentage of 43.5 of patients had a moderate level of comorbidity according to the resource utilisation band score. The mean time from diagnosis was 18.1 years and 7.5% of the patients died during the follow-up period. The most common comorbidities were dyslipidaemia (40.3%), hypertension (40.1%) and generalised pain (38.1%). Cirrhosis was associated with cardiovascular events (OR 3.8), organ failures (OR 2.2), alcoholism (OR 2.1), diabetes (OR 1.2) and age (OR 1.2); P<.05. The most commonly used medications were anti-infectives (67.8%) and nervous system medications (66.8%). The mean total cost per patient was 3,198€ (71.5% healthcare costs, 28.5% indirect/non-healthcare costs). In the corrected model, the total costs per patient-year were 2,211€ for those without cirrhosis and 7,641€ for patients with cirrhosis; P<.001.

CONCLUSIONS

Chronic hepatitis C virus patients are associated with a high level of comorbidity and the use of concomitant medications, especially in patients with liver cirrhosis. Chronic hepatitis C virus infection represents a substantial economic burden on the Spanish National Health System.

Predictive variables of sustained virological response after early discontinuation of triple therapy with telaprevir for genotype-1 HCV infection

BACKGROUND

Pivotal phase studies of telaprevir (TLV) and boceprevir (BOV) showed 10-56% rates of early treatment interruption. However, there have been no reports on the sustained virological response (SVR) rates of these patients.

AIM

To assess the SVR rate in a large cohort of patients who discontinued triple therapy with TLV or BOV for reasons other than stopping rules and to identify variables predicting SVR.

MATERIAL AND METHOD

A survey was sent to 15 hospitals in Catalonia asking them to report all TLV/BOV treatments finished by 31 May 2014. Demographic, clinical, laboratory, liver fibrosis and therapeutic data were recorded for treatments with early discontinuation. Logistic regression analysis, ROC curves and prognostic assessment of the variables identified were calculated.

RESULTS

Twelve hospitals responded to the survey, representing 467 treatments and 121 (21.2%) early discontinuations, 76 (62.8%) due to stopping rules and 45 (37.2%) for other reasons. Early discontinuation was more frequent with BOV [38.2% (50/131) versus 21.1% (71/336) p<0.005], mainly due to stopping rules [78% (39/50) versus 52.1% (37/71); p=0.004]. SVR was achieved in 21/121 patients (17.4%), 19/71 (26.8%) treated with TLV and 2/50 (4.0%) treated with BOV. In patients discontinuing treatment for reasons other than stopping rules, SVR was achieved in 19/37 (55.9%) treated with TLV and in 2/11 (18.2%) treated with BOV. The SVR rate in patients treated with TLV who discontinued due to a severe adverse event was 61.5% (16/26). A logistic regression analysis was performed only with triple therapy with TLV and early discontinuation. The predictive variables of SVR were undetectable HCV-RNA at treatment week 4 and treatment length longer than 11 weeks. Treatment duration longer than 11 weeks showed the best accuracy (0.794), with a positive predictive value of 0.928.

CONCLUSIONS

Early discontinuation of TLV-based triple therapy due to reasons other than stopping rules still have a significant SVR rate (55.9%). Undetectable HVC-RNA at week 4 of treatment and treatment duration longer than 11 weeks are predictive of SVR in this subset of patients.

Relevance of baseline viral genetic heterogeneity and host factors for treatment outcome prediction in hepatitis C virus 1b-infected patients

BACKGROUND

Only about 50% of patients chronically infected with HCV genotype 1 (HCV-1) respond to treatment with pegylated interferon-alfa and ribavirin (dual therapy), and protease inhibitors have to be administered together with these drugs increasing costs and side-effects. We aimed to develop a predictive model of treatment response based on a combination of baseline clinical and viral parameters.

METHODOLOGY

Seventy-four patients chronically infected with HCV-1b and treated with dual therapy were studied (53 retrospectively -training group-, and 21 prospectively -validation group-). Host and viral-related factors (viral load, and genetic variability in the E1-E2, core and Interferon Sensitivity Determining Region) were assessed. Multivariate discriminant analysis and decision tree analysis were used to develop predictive models on the training group, which were then validated in the validation group.

PRINCIPAL FINDINGS

A multivariate discriminant predictive model was generated including the following variables in decreasing order of significance: the number of viral variants in the E1-E2 region, an amino acid substitution pattern in the viral core region, the IL28B polymorphism, serum GGT and ALT levels, and viral load. Using this model treatment outcome was accurately predicted in the training group (AUROC = 0.9444; 96.3% specificity, 94.7% PPV, 75% sensitivity, 81% NPV), and the accuracy remained high in the validation group (AUROC = 0.8148, 88.9% specificity, 90.0% PPV, 75.0% sensitivity, 72.7% NPV). A second model was obtained by a decision tree analysis and showed a similarly high accuracy in the training group but a worse reproducibility in the validation group (AUROC = 0.9072 vs. 0.7361, respectively).

CONCLUSIONS AND SIGNIFICANCE

The baseline predictive models obtained including both host and viral variables had a high positive predictive value in our population of Spanish HCV-1b treatment naïve patients. Accurately identifying those patients that would respond to the dual therapy could help reducing implementation costs and additional side effects of new treatment regimens.

[To consider negative viral loads below the limit of quantification can lead to errors in the diagnosis and treatment of hepatitis C virus infection]

INTRODUCTION

For years many clinical laboratories have routinely classified undetectable and unquantifiable levels of hepatitis C virus RNA (HCV-RNA) determined by RT-PCR as below limit of quantification (BLOQ). This practice might result in erroneous clinical decisions.

AIM

To assess the frequency and clinical relevance of assuming that samples that are BLOQ are negative.

MATERIAL AND METHOD

We performed a retrospective analysis of RNA determinations performed between 2009 and 2011 (Cobas/Taqman, lower LOQ: 15 IU/ml). We distinguished between samples classified as «undetectable» and those classified as «<1.50E+01IU/mL» (BLOQ).

RESULTS

We analyzed 2.432 HCV-RNA measurements in 1.371 patients. RNA was BLOQ in 26 samples (1.07%) from 23 patients (1.68%). BLOQ results were highly prevalent among patients receiving Peg-Riba: 23 of 216 samples (10.6%) from 20 of 88 patients receiving treatment (22.7%). The clinical impact of BLOQ RNA samples was as follows: a) 2 patients initially considered to have negative results subsequently showed quantifiable RNA; b) 8 of 9 patients (88.9%) with BLOQ RNA at week 4 of treatment later showed sustained viral response; c) 3 patients with BLOQ RNA at weeks 12 and 48 of treatment relapsed; d) 4 patients with BLOQ RNA at week 24 and/or later had partial or breakthrough treatment responses, and e) in 5 patients the impact were null or could not be ascertained.

CONCLUSIONS

This study suggests that BLOQ HCV-RNA indicates viremia and that equating a BLOQ result with a negative result can lead to treatment errors. BLOQ results are highly prevalent in on-treatment patients. The results of HCV-RNA quantification should be classified clearly, distinguishing between undetectable levels and levels that are BLOQ.

[Clinical use of telaprevir: stopping rules, predicting response, treatment length, and management of adverse effects]

Triple combination therapy with pegylated interferon, ribavirin and telaprevir is currently considered the gold standard for the treatment of chronic hepatitis C virus (HCV) infection. The most important features are an increase in rates of sustained viral response (74-79% vs 46% with pegylated interferon and ribavirin), as well as the possibility of early cessation of ineffective therapy due to the application of futility rules at weeks 4 and 12 (HCV-RNA > 1,000 UI/ml), and the possibility of selecting candidates for the shortest treatments due to the clinical significance of extended rapid viral response (undetectable HCV-RNA at weeks 4 and 12 of triple therapy). Treatment length is mainly based on the stage of fibrosis and prior response to pegylated interferon and ribavirin. Thus, in both treatment-naïve patients and patients with recurrence after pegylated interferon therapy, the duration of treatment is 24 or 48 weeks (unless cirrhosis is present), depending on the presence of extended rapid viral response, while in cirrhotic patients and null responders, treatment length is 48 weeks. The main adverse effects of telaprevir therapy are anemia and skin rash. If these effects occur, the main measures that should be adopted are reduction of the ribavirin dose in anemia, and close monitoring and treatment cessation in skin rash, depending on its spread and severity.

Directly acting antivirals for the treatment of chronic hepatitis C: unresolved topics from registration trials

The Food and Drug Administration and European Medicines Agency approval of first generation directly acting antivirals NS3 protease inhibitors boceprevir and telaprevir opens a new era in the treatment of patients with chronic hepatitis C virus genotype 1 infection. Indeed telaprevir and boceprevir registration trials clearly showed a substantial improvement in rates of sustained virological response both in naive and in treatment-experienced patients, with the possibility of shortened regimens in a consistent subset of patients, through the optimization of treatment algorithms. Phases 2 and 3 studies also provided the basis for the management of side effects in order to maximize the safety profile of directly acting antivirals. However, the entry of triple therapy in current clinical practice comes with some unresolved topics, such as relevance of IL28B genetic testing and other pretreatment predictors in patient selection, use of the 4-week pretreatment lead-in phase with dual therapy, safety of triple therapy in some high-risk patient categories and specific management of directly acting antivirals-induced anaemia. As a consequence of these open issues, clinical practice guidelines on triple therapy released by American and European associations provide slightly different recommendations, effectively leaving these "grey" areas wide open for individual interpretation in everyday clinical practice.