FormalPara Key Summary Points

Why carry out this study?

Short-duration, pangenotypic direct-acting antivirals (DAA), such as glecaprevir/pibrentasvir (G/P), are increasingly important therapies, which can support countries’ paths to meet the World Health Organization’s target to eliminate hepatitis C virus (HCV).

Following a recent label (SmPC and USPI) update for G/P based on the EXPEDITION-8 study, there is a lack of large-scale real-world studies of similar magnitude (343 patients) for 8-week G/P therapy in treatment-naïve (TN) patients with compensated cirrhosis (CC). This review of smaller real-world studies will provide an up-to-date reference for clinicians making treatment decisions for patients with CC that may benefit from a shorter-duration therapy with G/P.

This review summarizes data from seven independent real-world studies to examine the effectiveness and safety of G/P treatment in HCV-infected TN patients with CC in clinical practice.

What was learned from the study?

G/P therapy for 8 weeks showed high effectiveness, with numerically high sustained virologic response rates at post-treatment week 12 (an average of 98.1% across cohorts), and was well tolerated.

This review can reassure providers that the results obtained across smaller real-world studies are collectively similar to that of EXPEDITION-8, where 343 patients were enrolled. This shorter treatment for TN patients with CC may also be beneficial in hard-to-reach populations.

Introduction

Effective pangenotypic hepatitis C virus (HCV) treatment is available through all-oral direct-acting antiviral (DAA) therapies [1]. However, despite the availability of these treatments, prevalence of HCV remains high, often due to a lack of diagnosis and treatment [2]. In 2016, it was reported that approximately 13% of patients aware of their positive HCV status were being treated [3].

If left untreated, chronic HCV infection can lead to complications such as hepatic decompensation and hepatocellular carcinoma, ultimately leading to death [1]. Untreated HCV infection may also lead to additional routes of transmission, particularly in high-risk groups [4]. The World Health Organization (WHO) has set a target to eliminate viral hepatitis as a major public health threat by 2030 by reducing new hepatitis B and C infections by 90% and hepatitis mortality by 65% [5]. However, many countries are not on track to meet the elimination targets by 2030 [3].

Glecaprevir/pibrentasvir (G/P) is an interferon-free, ribavirin-free, fixed-dose DAA drug combination approved for the treatment of chronic HCV genotype (GT) 1–6 [6, 7], with studies showing high rates of sustained virologic response (SVR) and well-tolerated safety profiles [8]. Recently, the EXPEDITION-8 trial demonstrated the efficacy and tolerability of G/P in 343 patients without any previous HCV treatment (treatment naïve [TN]) with compensated cirrhosis (CC) receiving treatment for 8 weeks [8]. These data supported an update of the G/P treatment label to include TN patients with CC for the 8-week regimen for GT1–6 in Europe [6], and the USA [7], whereas previously only patients without cirrhosis (either treatment-experienced patients with GT1, 2, 4–6 and TN patients with GT1–6) were eligible for this treatment duration. However, following this recent label update, there remains a lack of large-scale real-world data of a similar scale to the EXPEDITION-8 trial for 8-week G/P therapy in TN patients with CC. In lieu of a large prospective real-world cohort, this review summarizes data from seven smaller real-world studies to provide an up-to-date reference for clinicians making treatment decisions for patients with CC who may benefit from a shorter treatment duration.

Increasing the number of patients eligible for the shorter 8-week treatment with G/P has the potential to reach newly diagnosed TN patients by addressing barriers in the care cascade. It may also potentially offer additional advantages such as improved patient uptake [9] due to reduced treatment duration and monitoring, as well as improved adherence in patients who use drugs [10]. This review of data from seven separate cohort studies aims to summarize newly emerging data on TN patients with CC (Child–Pugh A) and HCV treated in real-world clinical practice with 8 weeks of G/P treatment and to further understand where additional real-world data are needed for newly diagnosed patients with HCV across multiple populations.

Methods

Study Selection

A literature synthesis of PubMed, American Association for the Study of Liver Disease Congress abstracts, and National AIDS Treatment Advocacy Project abstracts was conducted from August 2018 to April 2020 to identify publications reporting real-world evidence of 8-week G/P in TN patients with CC. All seven studies were retrospective, of which three were published or peer-reviewed published manuscripts and four were presented at major liver meetings. As this was a summary of published real-world studies, no ethic committee review was required. All studies included in this summary were approved by local institutional review committees, each patient also gave written informed consent before enrollment, and the protocol was conducted in accordance with the Declaration of Helsinki, with the exception of the Veterans Association study which did not require patient informed consent because the study was observational, the Scottish HCV study where data were obtained from the Scottish Hepatitis C Database for which opt-out consent is in place, and the TRIO study where TRIO Health Analytics were provided with de-identified Health Insurance Portability and Accountability Act-compliant patient information approved by the Western Institutional Review Board.

Patient Populations

We present a review of individual real-world effectiveness data from seven separate studies of TN patients with CC who were given G/P for 8 weeks. CC (Child–Pugh A) was defined as cirrhosis with no prior history of liver decompensation, consistent with label indicated populations [6, 7]. Decompensated cirrhosis was defined as current or past evidence of Child–Pugh B or C classification or clinical history of liver decompensation including ascites, bleeding esophageal varices, or hepatic encephalopathy, with the exception of the German hepatitis C-registry (DHC-R) which defined decompensated cirrhosis as at least one of the following: Child–Pugh B or C classification; ascites; encephalopathy; esophageal-varices grade > 1, red spots, bleeding; or model for end-stage liver disease score > 15.

Effectiveness Analyses

Effectiveness was measured using the SVR at post-treatment week 12 (SVR12). For the global post-marketing observation studies (PMOS), the core population with sufficient follow-up (CPSFU), which included patients who completed the label-recommended regimen and the availability of HCV ribonucleic acid (RNA) data after post-treatment day 70, virologic failure or discontinuation due to an adverse event with HCV RNA < 50 IU/mL at the last measurement was used for SVR12 analysis [11]. The Scottish HCV [12] and Italian MISTRAL [13] studies used the intention-to-treat (ITT) population, which included all patients. The DHC-R [14] used the modified ITT (mITT) population, which excluded patients lost to follow-up. The Italian NAVIGATORE [15], US TRIO Health Analytics [16], and US Department of Veterans Affairs (VA) [17] studies used the per-protocol (PP) population, which included patients who completed treatment. Safety profile, in terms of deaths and adverse events (AEs) where available, were assessed in TN patients with CC treated with G/P for 8 weeks.

Results

Data from a total of seven studies are presented: global PMOS [11], DHC-R [14], Scottish HCV [12], Italian MISTRAL [13], Italian NAVIGATORE [15], US TRIO Health Analytics [16], and US VA [17], with additional 8-week TN CC-specific data provided for inclusion in this review. Baseline patient demographics and clinical characteristics, including GT and fibrosis stage, are presented in Table 1.

Table 1 Baseline demographics and clinical characteristics for TN patients with CC, GT1–6a treated with 8-week G/P
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Efficacy

SVR12 rates were high (> 95.5%) across the majority of real-world studies included (Fig. 1).

Fig. 1
figure 1

SVR12 rates in TN patients with CC, GT1–6a treated with 8 weeks of G/P. aScottish HCV study included GT1,2,4–6, US VA study included GT1–3. bFour patients were lost to follow-up in the ITT population. cOne confirmed reinfection with subsequent spontaneous clearance, no virologic failure. dOne virologic failure. eOne patient died after completing treatment but before SVR12 testing, one patient was lost to follow-up. fPatients missing SVR12 data were excluded from SVR12 analysis. CC compensated cirrhosis, DHC-R German Hepatitis C-Registry, G/P glecaprevir/pibrentasvir, GT genotype, HCV hepatitis C virus, ITT intention-to-treat, PMOS post-marketing observational studies, SVR12 sustained virologic response at week 12, TN treatment-naïve, VA Veterans Association

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Safety

Of the seven studies, five (PMOS, Scottish HCV, MISTRAL, NAVIGATORE, and VA) had available safety data for TN patients with CC treated with G/P for 8 weeks. Across the 135 patients included in these cohorts, a total of two deaths were reported, 1/24 (4.2%) in the Scottish HCV study and 1/85 (1.2%) in the VA study [11,12,13, 15, 17]. Both deaths occurred post treatment and were not deemed DAA related.

There were substantial differences in the methodologies of safety reporting across the studies. However, the following safety profiles were available at the time of publication. In the PMOS study, 2/12 (16.7%) patients experienced an AE and no patients experienced a serious AE (SAE). In the Scottish HCV study, there were no significant AEs attributed to the study drug, and one death post treatment due to an illicit drug overdose. In the MISTRAL and NAVIGATORE studies there were no AEs reported. In the DHC-R study, the safety profile was only available for 16/20 patients, with no patient experiencing an SAE. The TRIO study was an effectiveness-only analysis and therefore no safety data were available. In the VA study there was one death post treatment but before SVR testing which was not deemed treatment related.

Discussion

In general, it seems possible that the effectiveness of HCV treatments in real-world clinical practice may be lower than that reported in clinical trials, potentially due to a more diverse population [18]. It is therefore important to examine effectiveness of HCV treatments in real-world populations given the consequences of treatment failure. Early real-world experience from these seven individual studies demonstrates the effectiveness of the 8-week G/P regimen in TN patients with CC with 212/216 (98.1%) patients achieving SVR and only 1/216 (0.5%) experiencing virologic failure. Further real-world studies are needed to support these results. Across most studies, the majority of patients were GT1, except the PMOS, MISTRAL, and NAVIGATORE studies where the majority of patients were GT3 (41.7%), GT2 (54.5%), and GT2 (67.3%), respectively [11,12,13,14,15]. Additional effectiveness and safety data, including migrants, prisoners, men who have sex with men, patients with mental health diagnoses, patients with comorbidities, and more descriptive drug use should be considered in future studies, as well as the under-representation of GT3, GT5, and GT6. However, patients with other GTs have shown similar real-world results as seen in clinical trials, providing reassurance to the applicability of a shortened treatment duration. Further research is also required on the potential for drug–drug interaction in TN patients with CC receiving 8-week G/P treatment, and possibly further shortening of HCV treatment given the high effectiveness shown. In addition, future studies are needed to demonstrate the value of a shorter treatment duration within test and treat programs and point-of-care approaches, where diagnosis and treatment are given in a single visit [19].

The heterogenous data summarized in this review are limited to the data available at the time of publication of the seven separate cohorts. Limitations arising from summarizing data captured from seven separate cohorts include the lack of uniform data collection and the limited utility of pooling data due to the different methodologies and study populations. Another limitation of this review is the use of mITT and CPSFU populations in some studies, which do not include missing SVR data for patients lost to follow-up and therefore only present data for patients who completed follow-up. This could potentially lead to underreported relapses and could potentially affect the conclusions drawn.

The majority of the real-world SVR12 rates presented here were similar to the results of the EXPEDITION 8 registration study (PP: 99.7% [334/335]) [8], which led to a G/P label update to include TN patients with CC for the 8-week regimen for GT1–6 in Europe [6] and the USA [7]. This similar efficacy is an important finding from this collection and review of smaller cohorts, which can be used in lieu of a large-scale prospective real-world study of a similar cohort size as in EXPEDITION-8. Increasing the number of patients with HCV who are eligible for shorter treatment duration has the potential to improve treatment initiation and completion, as well as reduce healthcare costs. This more inclusive indication for the 8-week treatment duration is of particular importance for TN patients with CC, in whom only a 12-week duration was previously possible, providing a new option for a shorter 8-week course of therapy to treat their HCV infection. Furthermore, the TN HCV-infected population is growing [20], with the majority of treatment-experienced patients successfully re-treated with DAAs. Epidemiology estimates suggest that as many as 98% of TN patients with HCV would have no cirrhosis or CC and therefore could be treated with, and are amenable to, the 8-week regimen [21]. In the USA, TN patients without cirrhosis and with CC represent 98% of the HCV patient population [16]; therefore, the majority of patients are eligible for 8-week treatment. Although similar high SVR12 rates are observed for the 12-week G/P regimen, patients may prefer a shorter duration because it is more convenient and requires less monitoring [9].

Conclusion

This summary of real-world data demonstrates that 8-week G/P is effective and well tolerated in TN patients with CC, supporting the results of EXPEDITION-8 and providing reassurance to clinicians treating patients with CC. Reducing treatment duration may help to address remaining gaps in the cascade of care, such as a lack of treatment initiation on behalf of either the patient or the physician and losing patients to follow-up. It may have greater application in underserved patients, such as prisoners and those with unstable lifestyles/addictive substance use whose engagement with healthcare can be challenging.