Glecaprevir and pibrentasvir yield high response rates in patients with HCV genotype 1-6 without cirrhosis

Quinoxaline-Based Linear HCV NS3/4A Protease Inhibitors Exhibit Potent Activity against Drug Resistant Variants

A series of linear HCV NS3/4A protease inhibitors was designed by eliminating the P2-P4 macrocyclic linker in grazoprevir, which, in addition to conferring conformational flexibility, allowed structure-activity relationship (SAR) exploration of diverse quinoxalines at the P2 position. Biochemical and replicon data indicated preference for small hydrophobic groups at the 3-position of P2 quinoxaline for maintaining potency against resistant variants R155K, A156T, and D168A/V. The linear inhibitors, though generally less potent than the corresponding macrocyclic analogues, were relatively easier to synthesize and less susceptible to drug resistance. Three inhibitor cocrystal structures bound to wild-type NS3/4A protease revealed a conformation with subtle changes in the binding of P2 quinoxaline, depending on the 3-position substituent, likely impacting both inhibitor potency and resistance profile. The SAR and structural analysis highlight inhibitor features that strengthen interactions of the P2 moiety with the catalytic triad residues, providing valuable insights to improve potency against resistant variants.

Development of a Comprehensive Dataset of Hepatitis C Patients and Examination of Disease Epidemiology in the United States, 2013-2016

INTRODUCTION

Chronic infection with hepatitis C virus (HCV) is a leading cause of liver disease and infectious disease deaths. While recent and emerging treatment options for HCV patients have enabled higher rates of sustained virologic response (SVR), the demographic, clinical, geographic, and payer characteristics of the estimated 3.4 million chronic HCV patients in the USA are poorly understood. The goal of this study was to create a dataset describing the current HCV patient landscape in the USA.

METHODS

Data from two large national laboratory companies representing the majority of US patients screened for HCV antibody and/or tested for HCV RNA from 2013 through 2016 were organized into the present study dataset. Age, gender, payer channel, 3-digit ZIP code and ordering physician specialty, and 3-digit ZIP code information were available for all patients. Among RNA-positive patients, additional clinical characteristics included HCV genotype, fibrosis stage, renal function, and HIV status. Initiating treatment and attaining cure were imputed using data-driven algorithms based on successive RNA viral load measurements.

RESULTS

The number of RNA-positive HCV patients increased from 200,066 patients in 2013 to 469,550 in 2016. The availability of clinical data measurements and rates of treatment initiation increased over the study period, indicating improved care engagement for HCV patients. Treatment and cure rates varied by age, disease severity, geographic location, and payer channel. Sensitivity and specificity of the cure prediction algorithms were consistently above 0.90, validating the robustness of the data imputation approach.

CONCLUSION

This is the largest, most comprehensive dataset available to describe the current US HCV patient landscape. Our results highlight that the epidemiology of HCV is evolving with an increasing number of patients who are younger and have milder disease than described in previous years. Results of this study should help guide efforts toward the elimination of HCV in this country. Future work will focus on factors associated with varying treatment and cure patterns and describing recent changes in the HCV patient landscape.

FUNDING

AbbVie. Plain language summary available for this article.

Management of acute HCV infection in the era of direct-acting antiviral therapy

The management of acute HCV infection has not been standardized following the availability of direct-acting antiviral agents (DAAs) for chronic HCV infection, and substantial uncertainty exists regarding the optimal treatment regimen and duration. Despite the lack of direct evidence, the 2016 American Association for the Study of Liver Diseases (AASLD)-Infectious Diseases Society of America (IDSA) guidelines supported "the same regimens for acute HCV as recommended for chronic HCV infection … owing to high efficacy and safety", whereas the 2016 European Association for the Study of the Liver (EASL) guidelines recommended sofosbuvir-ledipasvir, sofosbuvir-velpatasvir or sofosbuvir plus daclatasvir for 8 weeks in acute HCV infection, with a longer duration of 12 weeks recommended for those infected with HIV and/or baseline HCV RNA levels >1,000,000 IU/ml. This Review outlines the epidemiology, natural history and diagnosis of acute HCV infection and provides contemporary information on DAAs for acute and recent HCV infection. The Review also discusses the 2016 AASLD-IDSA and EASL recommendations for acute HCV infection management in light of available evidence and highlights key differences in study populations and design that influence interpretation. We focus on populations at high risk of HCV transmission and acquisition, including people who inject drugs and HIV-positive men who have sex with men, and highlight the potential effects of diagnosis and treatment of acute HCV infection in contributing to HCV elimination.

Real-world effectiveness of sofosbuvir plus ribavirin for chronic hepatitis C genotype 2 in Asia: a systematic review and meta-analysis

BACKGROUND

Sofosbuvir plus ribavirin (SOF+RBV) for 12 weeks is the standard treatment for chronic hepatitis C (CHC) genotype 2 (GT2) in most of Asia despite availability of new CHC medications. SOF-RBV real-world effectiveness has only been reported in small and/or single-centre studies. Our goal was to determine the real-world effectiveness of 12-week SOF+RBV therapy for CHC GT2 in Asia.

METHODS

A systematic search on PubMed and Embase was conducted through 30 June 2017. We identified full articles and conference proceedings of at least 10 adult patients with CHC GT2 treated with SOF+RBV for 12 weeks under real-world setting in Asia.

RESULTS

A total of 2208 patients from 13 studies were included. The pooled sustained virological response 12 weeks after the end of treatment (SVR12) was 95.8% (95% CI 94.6% to 96.9%) with non-significant heterogeneity (I2=34.4%). Anaemia (27.9%) was the most common adverse event (AE), with serious AEs in 2.0% and only 0.7% discontinued therapy prematurely. In subgroup analyses, patients with cirrhosis had 8.7% lower SVR12 than non-cirrhotic patients (P<0.0001), and treatment-experienced patients had 7.2% lower SVR12 than treatment-naïve patients (P=0.0002). Cirrhotic treatment-experienced patients had the lowest SVR12 at 84.5%. There were no significant differences in pooled SVR12 among patient subgroups: RBV dose reduction versus no dose reduction (P=0.30); hepatocellular carcinoma (HCC) versus no HCC (P=0.10); GT 2a versus 2b (P=0.86); and <65 vs ≥65 years of age (P=0.20).

CONCLUSIONS

SOF+RBV for 12 weeks was safe and effective for patients with CHC GT2 in Asia, although those with cirrhosis and prior treatment failure had a lower pooled SVR12 rate.

TRIAL REGISTRATION NUMBER

CRD42017067928.

Prevalence of Single and Multiple Natural NS3, NS5A and NS5B Resistance-Associated Substitutions in Hepatitis C Virus Genotypes 1-4 in Italy

Natural resistance-associated substitutions (RASs) are reported with highly variable prevalence across different HCV genotypes (GTs). Frequency of natural RASs in a large Italian real-life cohort of patients infected with the 4 main HCV-GTs was investigated. NS3, NS5A and NS5B sequences were analysed in 1445 HCV-infected DAA-naïve patients. Sanger-sequencing was performed by home-made protocols on 464 GT1a, 585 GT1b, 92 GT2c, 199 GT3a, 16 GT4a and 99 GT4d samples. Overall, 20.7% (301/1455) of patients showed natural RASs, and the prevalence of multiclass-resistance was 7.3% (29/372 patients analysed). NS3-RASs were particularly common in GT1a and GT1b (45.2-10.8%, respectively), mainly due to 80K presence in GT1a (17%). Almost all GTs showed high prevalence of NS5A-RASs (range: 10.2-45.4%), and especially of 93H (5.1%). NS5A-RASs with fold-change >100x were detected in 6.8% GT1a (30H/R-31M-93C/H), 10.3% GT1b (31V-93H), 28.4% GT2c (28C-31M-93H), 8.5% GT3a (30K-93H), 45.5% GT4a (28M-30R-93H) and 3.8% GT4d (28V-30S-93H). Sofosbuvir RAS 282T was never detected, while the 159F and 316N RASs were found in GT1b (13.4-19.1%, respectively). Natural RASs are common in Italian patients infected with HCV-GTs 1-4. High prevalence of clinically-relevant RASs (such as Y93H) supports the appropriateness of HCV resistance-test to properly guide DAA-based therapy.

Pharmacokinetic and pharmacodynamic evaluation of daclatasvir, asunaprevir plus beclabuvir as a fixed-dose co-formulation for the treatment of hepatitis C

INTRODUCTION

Many reports have evaluated the clinical efficacy and safety of the fixed-dose all-oral combination of daclatasvir, asunaprevir, and beclabuvir (DCV-TRIO), which was approved in Japan in December 2016 for the treatment of hepatitis C genotype (GT)-1 infection. Areas covered: This article reviews the pharmacodynamic and pharmacokinetic properties of the DCV-TRIO combination. The topics covered include data regarding the drug's absorption, distribution, metabolism, excretion, and antiviral activity strategies. Its therapeutic efficacy and safety in GT-1 infection from phase 2/3 clinical trials are also discussed. Expert opinion: The ideal regimen for the treatment of Hepatitis C virus infection should be potent, pangenotypic, Ribavirin-free, safe, co-formulated, and affordable. Considering these characteristics, DCV-TRIO is neither pangenotypic nor potent enough against GT-1a, regardless of the presence or absence of cirrhosis. Other potential limitations of this regimen are its dosification (twice-daily), and the fact that since it includes a protease inhibitor, it is contraindicated in decompensated cirrhosis. For these reasons, it has only been approved in Japan, where more than 70% of the patients are infected with GT-1b. However, this co-formulation might still have a place in the treatment of non-cirrhotic patients infected with GT-1b provided that massive access to treatment is facilitated.

Impact of hepatitis C virus polymorphisms on direct-acting antiviral treatment efficacy: Regulatory analyses and perspectives

Several highly effective, interferon-free, direct-acting antiviral (DAA)-based regimens are available for the treatment of chronic hepatitis C virus (HCV) infection. Despite impressive efficacy overall, a small proportion of patients in registrational trials experienced treatment failure, which in some cases was associated with the detection of HCV resistance-associated substitutions (RASs) at baseline. In this article, we describe methods and key findings from independent regulatory analyses investigating the impact of baseline nonstructural (NS) 3 Q80K and NS5A RASs on the efficacy of current United States Food and Drug Administration (FDA)-approved regimens for patients with HCV genotype (GT) 1 or GT3 infection. These analyses focused on clinical trials that included patients who were previously naïve to the DAA class(es) in their investigational regimen and characterized the impact of baseline RASs that were enriched in the viral population as natural or transmitted polymorphisms (i.e., not drug-selected RASs). We used a consistent approach to optimize comparability of results across different DAA regimens and patient populations, including the use of a 15% sensitivity cutoff for next-generation sequencing results and standardized lists of NS5A RASs. These analyses confirmed that detection of NS3 Q80K or NS5A baseline RASs was associated with reduced treatment efficacy for multiple DAA regimens, but their impact was often minimized with the use of an intensified treatment regimen, such as a longer treatment duration and/or addition of ribavirin. We discuss the drug resistance-related considerations that contributed to pretreatment resistance testing and treatment recommendations in drug labeling for FDA-approved DAA regimens.

CONCLUSION

Independent regulatory analyses confirmed that baseline HCV RASs can reduce the efficacy of certain DAA-based regimens in selected patient groups. However, highly effective treatment options are available for patients with or without baseline RASs. (Hepatology 2018;67:2430-2448).

Glecaprevir/pibrentasvir expands reach while reducing cost and duration of hepatitis C virus therapy

Hepatitis C virus (HCV) treatments have dramatically progressed from poorly tolerated, moderately successful interferon-based therapies to highly effective all-oral interferon-free regimens. While sustained virologic responses have significantly improved with fixed-dose combinations (FDC) of these direct-acting antivirals (DAA), cost remains high and certain populations of patients remain difficult to treat. Glecaprevir (GLE, an NS3/4A protease inhibitor) and pibrentasvir (PIB, NS5A inhibitor) were recently approved as a FDC therapy for HCV, and have expanded reach, reduced cost, and in certain populations, reduced HCV treatment duration. GLE/PIB is effective across all genotypes, and has been shown to be effective in HIV-infected patients, patients with chronic kidney disease, and Child-Pugh A-compensated cirrhosis. GLE/PIB is also effective for a shortened duration of 8 weeks in treatment-naive non-cirrhotic patients.

Highlights of the Structure-Activity Relationships of Benzimidazole Linked Pyrrolidines Leading to the Discovery of the Hepatitis C Virus NS5A Inhibitor Pibrentasvir (ABT-530)

Curative interferon and ribavirin sparing treatments for hepatitis C virus (HCV)-infected patients require a combination of mechanistically orthogonal direct acting antivirals. A shared component of these treatments is usually an HCV NS5A inhibitor. First generation FDA approved treatments, including the component NS5A inhibitors, do not exhibit equivalent efficacy against HCV virus genotypes 1-6. In particular, these first generation NS5A inhibitors tend to select for viral drug resistance. Ombitasvir is a first generation HCV NS5A inhibitor included as a key component of Viekira Pak for the treatment of patients with HCV genotype 1 infection. Since the launch of next generation HCV treatments, functional cure for genotype 1-6 HCV infections has been achieved, as well as shortened treatment duration across a wider spectrum of genotypes. In this paper, we show how we have modified the anchor, linker, and end-cap architecture of our NS5A inhibitor design template to discover a next generation NS5A inhibitor pibrentasvir (ABT-530), which exhibits potent inhibition of the replication of wild-type genotype 1-6 HCV replicons, as well as improved activity against replicon variants demonstrating resistance against first generation NS5A inhibitors.

Hepatitis C care continuum and associated barriers among people who inject drugs in Chennai, India

BACKGROUND

Little is known regarding barriers to hepatitis C virus (HCV) treatment among people who inject drugs (PWID) in low-resource settings, particularly in the era of direct-acting antiviral therapies.

METHODS

Between March, 2015-August, 2016, a cross-sectional survey was administered to community-based PWID in Chennai, India to examine the HCV care continuum and associated barriers. Adjusted prevalence ratios (APR) were estimated by multivariable Poisson regression with robust variance.

RESULTS

All participants were male (n = 541); 152 participants had HCV mono-infection and 61 participants had HIV/HCV co-infection. Only one HCV mono-infected and one HIV/HCV co-infected participant was linked to HCV care. Overall, there was moderate knowledge of HCV disease but poor knowledge of HCV treatment. Higher total knowledge scores were negatively associated with HIV/HCV co-infection (vs. HCV mono-infection), though this was not statistically significant in adjusted analysis (APR = 0.71 [95%CI = 0.47-1.06]). Participants ≥45 years (APR = 0.73 [95%CI = 0.58-0.92]) and participants with HIV/HCV co-infection (APR = 0.64 [95%CI = 0.47-0.87]) were less willing to take weekly interferon injections for 12 weeks. Willingness to undergo HCV treatment improved with decreasing duration of therapy, higher perceived efficacy, and use of pills vs. interferon, though willingness to use interferon improved with decreasing duration of therapy. Most participants preferred daily visits to a clinic for HCV treatment versus receiving a month's supply. Participants ≥45 years (vs. <45 years; APR = 0.70 [95%CI = 0.56-0.88]) and participants with HIV/HCV co-infection (APR = 0.75 [95%CI = 0.57-0.98]) were less likely to intend on seeking HCV care. Common reasons for not having already seen a provider for HCV treatment differed by HIV status, and included low perceived need for treatment (HCV-mono-infected), competing money/health priorities and costs/fears about treatment (HIV/HCV-co-infected).

CONCLUSION

Residual gaps in HCV knowledge and continuing negative perceptions related to interferon-based therapy highlight the need to scale-up educational initiatives. Readiness for HCV treatment was particularly low among HIV/HCV co-infected and older PWID, emphasizing the importance of tailored treatment strategies.

Formulary Drug Reviews: Glecaprevir/Pibrentasvir

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Efficacy and safety of glecaprevir/pibrentasvir in Japanese patients with chronic genotype 1 hepatitis C virus infection with and without cirrhosis

BACKGROUND

The once-daily, all oral, RBV-free, pangenotypic direct-acting anti-viral regimen consisting of co-formulated NS3/4A protease inhibitor glecaprevir and NS5A inhibitor pibrentasvir (G/P), demonstrated high rates of sustained virologic response (SVR) in phase 2 and 3 studies outside Japan.

METHODS

CERTAIN-1 is a phase 3, open-label, multicenter study assessing the safety and efficacy of G/P (300/120 mg) once daily in Japanese patients with chronic HCV GT1 infection. Patients without cirrhosis received 8 weeks of G/P or 12 weeks of ombitasvir/paritaprevir/ritonavir (OBV/PTV/r, 25/150/100 mg); patients with cirrhosis received G/P for 12 weeks. The primary efficacy endpoint was non-inferiority of G/P compared to OBV/PTV/r by assessing SVR at post-treatment week 12 (SVR12) among non-cirrhotic patients without the NS5A Y93H polymorphism.

RESULTS

SVR12 was achieved by 128/129 (99.2%; one patient lost to follow-up) non-cirrhotic patients in the 8-week G/P Arm (including 23/23 patients with the NS5A Y93H polymorphism) and 52/52 (100%) patients in the 12-week OBV/PTV/r Arm. No patients from the G/P Arm prematurely discontinued the study drug or experienced a treatment-emergent serious adverse event (TESAE). Three patients from the OBV/PTV/r Arm experienced five TESAEs and one of these patients discontinued the study drug due to TESAEs. All 38 (100%) patients with compensated cirrhosis achieved SVR12; in this group, no TESAEs were reported and one patient discontinued treatment due to an AE.

CONCLUSIONS

CERTAIN-1 study results demonstrate high efficacy and favorable tolerability of G/P in GT1-infected Japanese patients including those with the NS5A Y93H polymorphism, with no virologic failures observed.

Evaluation of the cobas® GT hepatitis C virus genotyping assay in G1-6 viruses including low viral loads and LiPA failures

Direct-acting antiviral (DAA) drug performances depend on the viral genotype. So international recommendations give typing of the virus a prerequisite for treatment choice and patient management. Commercially available HCV genotyping kits are scarce and this analysis is often in-house using tedious PCRs and Sanger sequencing, leading to a lack of standardization. A newly commercialized HCV genotyping assay based on real-time PCR has been developed by Roche Diagnostics (Mannheim, Germany). We compared this new assay with our in-house PCRs -sequencing technique on 101 regular samples and 81 LiPA failures or low viral load samples. No genotype or 1a/1b subtype mismatch was observed. Two samples were misidentified at the subtype level without clinical impact. Three genotype 1b and two genotype 1a samples with low viral load could not be subtyped. Nevertheless, 13 (13%) samples from the regular panel and 35 (43%) from the more difficult-to-type panels failed to give results on first pass with the Roche kit. Failures were mostly associated with genotype 3 subtype a, with genotype 4 subtype non-a, or with viral loads <200 IU/mL (p = 0.0061). The workflow allowed a non-specialized technician to obtain results in less than 4 hours whereas 2 to 3 days and experienced staff were required with the in-house assay. In conclusion, the Roche cobas^® HCV GT kit is easy and rapid to use and provides reliable results. The high rate of uninterpretable results particularly for low viral load samples and less frequent genotypes, and the absence of subtyping for non-genotype 1 could require sending complex samples to a specialized laboratory.

Direct acting antivirals for the treatment of hepatitis C in ethnic minority populations

INTRODUCTION

Direct acting antivirals (DAA's) have revolutionized the treatment of hepatitis C (HCV). However, questions persist concerning their efficacy in minority populations.

AREAS COVERED

In this review, the authors review outcomes for treatment of HCV by race and ethnicity among the clinical trials that have led to the current recommended treatments for HCV. The authors highlight the efficacy and safety differences by race and ethnicity. They also highlight deficiencies within the literature including small populations of racial/ethnic minorities within HCV clinical trials. DAA's can achieve cure rates for HCV over 95% with the use of once daily medications that have minimal side effects and few significant drug-drug interactions. Regimens with high pan-genotypic efficacy have further simplified treatment paradigms. The purpose of this review is to describe the data on DAA's in treating HCV in racial/ethnic populations.

EXPERT OPINION

While the overall data in racial/ethnic minority populations is sparse, DAA's appear to have high efficacy in curing HCV in diverse racial/ethnic populations. Although achieving high sustained virologic response (SVR) rates, there are also data that suggests that some disparities in SVR persist, especially when considering shorter regimens for HCV treatment in racial/ethnic populations.

Resistance to DAAs: When to Look and When It Matters

PURPOSE OF REVIEW

This review provides an overview of HCV resistance-associated substitutions (RASs) with a focus on NS3 protease and NS5A inhibitor resistance. Treatment approaches for managing resistance are also covered including the use of newly approved therapies with improved resistance profiles.

RECENT FINDINGS

HCV RASs are frequently selected if the patient is not cured during treatment; NS5A RASs persist for prolonged periods of time (years) after treatment failure and may adversely impact retreatment responses. Newly approved regimens with improved potency and resistance profiles are less impacted by resistance and provide the best retreatment options for patients who previously failed DAA therapy. The clinical impact of HCV RASs has been lessened significantly with the introduction of new DAA treatment regimens. Routine testing for resistance is unlikely to impact retreatment approaches if newer regimens are accessible. Knowledge of factors, such as the presence of cirrhosis and prior treatment regimens, remain as the key to optimizing retreatment approaches.

Glecaprevir + pibrentasvir for treatment of hepatitis C

Glecaprevir/pibrentasvir is a fixed-dose combination regimen of a new generation NS3/4A inhibitor and an NS5A inhibitor with potent antiviral activity against all hepatitis C virus (HCV) genotypes. This regimen offers a shorter course of therapy (8 weeks) for selected patients regardless of genotype and has demonstrated high virological efficacy for retreatment of individuals who previously failed an NS5A containing regimen. Glecaprevir and pibrentasvir are minimally excreted by the kidneys; thus this regimen can safely be used in individuals with severe chronic kidney disease (CKD), including those undergoing hemodialysis. Areas covered: This review covers the mechanism of action, pharmacokinetics, clinical applications, efficacy, and safety profile of glecaprevir/pibrentasvir. It also covers key phase 2 and 3 clinical trials that led to licensure of this regimen. Expert opinion: Glecaprevir/pibrentasvir is the latest antiviral regimen licensed in the United States for treatment of HCV infection. Although several other direct-acting antiviral agents (DAAs) are currently available, glecaprevir/pibrentasvir has some unique characteristics that expand treatment options for HCV infection, including patients with comorbidities such as advanced stage CKD or prior treatment failure to antiviral regimens containing other DAAs.

Efficacy of Glecaprevir/Pibrentasvir for 8 or 12 Weeks in Patients With Hepatitis C Virus Genotype 2, 4, 5, or 6 Infection Without Cirrhosis

BACKGROUND & AIMS

Hepatitis C virus (HCV) has high genotypic diversity and global distribution. Agents that are effective against all major HCV genotypes, with shorter treatment duration, are needed to reduce disease burden. Glecaprevir (an NS3/4A protease inhibitor) and pibrentasvir (an NS5A inhibitor) have a high barrier to resistance and synergistic antiviral activity. We evaluated the safety and efficacy of 8 and 12 weeks' treatment with glecaprevir/pibrentasvir in patients with HCV genotype 2, 4, 5, or 6 infection without cirrhosis in 3 separate phase 3 trials.

METHODS

We performed 2 open label, single-arm studies (SURVEYOR-II, Part 4 and ENDURANCE-4) and a randomized, double-blind, placebo-controlled study (ENDURANCE-2). In the ENDURANCE-2 study, adult patients with untreated or previously treated HCV genotype 2 infection without cirrhosis were randomly assigned (2:1) to groups given once-daily oral glecaprevir/pibrentasvir (n = 202; 300 mg/120 mg) or placebo (n = 100) for 12 weeks. In the SURVEYOR-II, Part 4 and ENDURANCE-4 studies, adult patients with untreated or previously treated patients with HCV genotype 2, genotype 4, genotype 5, or genotype 6 infection, without cirrhosis, were given once-daily oral glecaprevir/pibrentasvir (n = 121 in ENDURANCE-4 and n = 145 in SURVEYOR-II) for 12 or 8 weeks, respectively. In all studies the primary endpoint was sustained virologic response at 12 weeks after treatment (SVR12) in the intention-to-treat population.

RESULTS

Among patients receiving glecaprevir/pibrentasvir for 8 weeks, rates of SVR12 were 98% (95% CI, 94.1-99.3) in those infected with HCV genotype 2 and 93% (95% CI, 83.6-97.3) in those infected with HCV genotypes 4, 5, or 6. Among patients receiving glecaprevir/pibrentasvir for 12 weeks, rates of SVR12 were 99.5% (95% CI, 98.5-100) in those infected with HCV genotype 2 and 99% (95% CI, 97.6-100) in those infected with HCV genotype 4, 5, or 6. No virologic failures occurred in patients with HCV genotype 4, 5, or 6 infections. The frequency and severity of adverse events in patients receiving glecaprevir/pibrentasvir were similar to those of patients who received placebo.

CONCLUSION

In 3 Phase 3 studies, 8 weeks' treatment with glecaprevir/pibrentasivr produced an SVR12 in at least 93% of patients with chronic HCV genotype 2, 4, 5, or 6 infection without cirrhosis, with virologic failure in less than 1%. The drug combination had a safety profile comparable to 12 week's treatment with glecaprevir/pibrentasvir. ClinicalTrials.gov numbers: NCT02640482 (ENDURANCE-2), NCT02636595 (ENDURANCE-4), and NCT02243293 (SURVEYOR-II).

Treatment of hepatitis C virus infection for adults and children: updated Swedish consensus guidelines 2017

AIM

Following the approval of two new therapeutic combinations within the European Union in 2017, the former Swedish recommendations for the treatment of hepatitis C virus (HCV) infection from 2016 were deemed in need of updating.

MATERIALS AND METHODS

An expert meeting to this end was held in Stockholm, Sweden in October 2017.

RESULTS AND CONCLUSIONS

An interferon-free combination of direct-acting antiviral agents is now recommended for all patients with chronic HCV infection, regardless of liver fibrosis stage, in order to limit morbidity and spread of the disease. An extended discussion of treatment for people who inject drugs in order to diminish transmission is included.

Effects of Renal Impairment and Hemodialysis on the Pharmacokinetics and Safety of the Glecaprevir and Pibrentasvir Combination in Hepatitis C Virus-Negative Subjects

Hepatitis C virus (HCV) infection is an independent risk factor for developing chronic renal impairment and end-stage renal disease. Limited treatment options are available for HCV genotype 2, 3, 5, and 6 infections in patients with an estimated glomerular filtration rate (eGFR) of <30 ml/min. Glecaprevir and pibrentasvir are active against all six major HCV genotypes, are primarily excreted in the bile, and have minimal renal elimination. Therefore, combined treatment with these direct-acting antivirals may be useful for patients with HCV infection and chronic kidney disease. A phase 1, multicenter, open-label study evaluated the effects of renal impairment on the pharmacokinetics and safety of glecaprevir-pibrentasvir. In substudy 1, 38 subjects with stage 2 to 5 chronic kidney disease who were not on dialysis or who had normal renal function received single doses of the combination of 300 mg glecaprevir and 120 mg pibrentasvir. In substudy 2, 8 subjects requiring hemodialysis received single doses of the combination of 300 mg glecaprevir and 120 mg pibrentasvir under dialysis and nondialysis conditions. Regression analyses demonstrated increased glecaprevir and pibrentasvir plasma exposures, as determined by the area under the curve, with decreasing renal function, up to 56% and 46%, respectively, in subjects with an eGFR of <15 ml/min/1.73 m² In dialysis-dependent subjects, glecaprevir and pibrentasvir exposures were similar (≤18% difference) when study drugs were administered before hemodialysis or on a nondialysis day. Adverse events were mostly mild, with the most common being self-limited fatigue (3 subjects). The study findings support the clinical evaluation of glecaprevir-pibrentasvir without dose adjustment in HCV-infected subjects with renal impairment. (This study has been registered at ClinicalTrials.gov under registration number NCT02442258.).

Efficacy and safety results of patients with HCV genotype 2 or 3 infection treated with ombitasvir/paritaprevir/ritonavir and sofosbuvir with or without ribavirin (QUARTZ II-III)

The efficacy and safety of an investigational combination of ombitasvir/paritaprevir/ritonavir (OBV/PTV/r) plus sofosbuvir (SOF) ± ribavirin (RBV) in patients with HCV genotype 2 or 3 infection with or without cirrhosis was evaluated. Patients with HCV genotype 3 infection without cirrhosis were randomized to receive OBV/PTV/r + SOF ± RBV for 12 weeks; OBV/PTV/r + SOF + RBV was administered to genotype 3-infected patients with cirrhosis for 12 weeks and to genotype 2-infected patients without cirrhosis for either 6 or 8 weeks. Efficacy was assessed by sustained virologic response [HCV RNA <25 IU/mL] 12 weeks post-treatment (SVR12). Safety was assessed in all treated patients. In patients with genotype 3 infection with or without cirrhosis treated with 12 weeks of OBV/PTV/r + SOF ± RBV, the overall SVR12 rate was 98% (50/51), with no virologic failures. Patients with genotype 2 infection treated with OBV/PTV/r + SOF + RBV had SVR12 rates of 90% (9/10) and 44% (4/9) following 8- and 6-week treatment durations, respectively; failure to achieve SVR12 for these patients was due to relapse without baseline or treatment-emergent resistance-associated substitutions. Thus, the investigational combination of OBV/PTV/r with SOF ± RBV was well tolerated and achieved high SVR rates with no virologic failures in patients with genotype 3 infection. Combining direct-acting antivirals with complementary mechanisms of action and different viral targets may be an effective treatment strategy that may allow for shorter durations of therapy.

The next wave of hepatitis C virus: The epidemic of intravenous drug use

The epidemic of hepatitis C virus (HCV) began in the 1960s when transmission was primarily the result of blood transfusions. By 1990, when HCV was identified and a serologic test for screening donated blood was implemented, 123 million persons had already become infected worldwide and HCV was the most common cause of cirrhosis, hepatocellular carcinoma and the most common indication for liver transplantation. Approximately 75% of persons with HCV are "baby boomers" born between the years 1945 and 1965. The number of new cases of HCV declined precipitously between 1990 and 2005. The next wave of HCV began in 2005, and transmission is primarily the result of an epidemic of intravenous drug use. New cases of HCV have increased three-fold between 2005 and 2015. Approximately 50% of persons who inject drugs (PWID) have been exposed to HCV, and 25% of these persons are under the age of 25 years. The treatment of chronic HCV in PWID has two goals; treating HCV and preventing the patient from returning to drug use and becoming reinfected. Highly effective oral antiviral agents are now available and can cure HCV in virtually all patients. Treatment can be highly effective in PWID with sustained virologic response rates similar to that observed in a non-drug-using population. Preventing the patient from returning to drug use and becoming reinfected with HCV is more difficult and will require that the medical and social problems associated with intravenous drug use be addressed and resolved.

Glecaprevir/pibrentasvir for hepatitis C virus genotype 3 patients with cirrhosis and/or prior treatment experience: A partially randomized phase 3 clinical trial

This study assessed the efficacy and safety of ribavirin-free coformulated glecaprevir/pibrentasvir (G/P) in patients with hepatitis C virus genotype 3 infection with prior treatment experience and/or compensated cirrhosis, a patient population with limited treatment options. SURVEYOR-II, Part 3 was a partially randomized, open-label, multicenter, phase 3 study. Treatment-experienced (prior interferon or pegylated interferon ± ribavirin or sofosbuvir plus ribavirin ± pegylated interferon therapy) patients without cirrhosis were randomized 1:1 to receive 12 or 16 weeks of G/P (300 mg/120 mg) once daily. Treatment-naive or treatment-experienced patients with compensated cirrhosis were treated with G/P for 12 or 16 weeks, respectively. The primary efficacy endpoint was the percentage of patients with sustained virologic response at posttreatment week 12 (SVR12). Safety was evaluated throughout the study. There were 131 patients enrolled and treated. Among treatment-experienced patients without cirrhosis, SVR12 was achieved by 91% (20/22; 95% confidence interval [CI], 72-97) and 95% (21/22; 95% CI, 78-99) of patients treated with G/P for 12 or 16 weeks, respectively. Among those with cirrhosis, SVR12 was achieved by 98% (39/40; 95% CI, 87-99) of treatment-naive patients treated for 12 weeks and 96% (45/47; 95% CI, 86-99) of patients with prior treatment experience treated for 16 weeks. No adverse events led to discontinuation of study drug, and no serious adverse events were related to study drug. Conclusion: Patients with hepatitis C virus genotype 3 infection with prior treatment experience and/or compensated cirrhosis achieved high SVR12 rates following 12 or 16 weeks of treatment with G/P. The regimen was well tolerated. (Hepatology 2018;67:514-523).

Integrated Resistance Analysis of CERTAIN-1 and CERTAIN-2 Studies in Hepatitis C Virus-Infected Patients Receiving Glecaprevir and Pibrentasvir in Japan

Glecaprevir and pibrentasvir are hepatitis C virus (HCV) pangenotypic inhibitors targeting NS3/4A protease and NS5A, respectively. This once-daily, fixed-dose combination regimen demonstrated high sustained virologic response 12 weeks postdosing (SVR12) rates in CERTAIN-1 and CERTAIN-2 studies in Japanese HCV-infected patients, with a low virologic failure rate (1.2%). There were no virologic failures among direct-acting antiviral (DAA)-treatment-naive genotype 1a (GT1a) (n = 4)-, GT1b (n = 128)-, and GT2 (n = 97)-infected noncirrhotic patients treated for 8 weeks or among GT1b (n = 38)- or GT2 (n = 20)-infected patients with compensated cirrhosis treated for 12 weeks. Two of 33 DAA-experienced and 2 of 12 GT3-infected patients treated for 12 weeks experienced virologic failure. Pooled resistance analysis, grouped by HCV subtype, treatment duration, prior treatment experience, and cirrhosis status, was conducted. Among DAA-naive GT1b-infected patients, the baseline prevalence of NS3-D168E was 1.2%, that of NS5A-L31M was 3.6%, and that of NS5A-Y93H was 17.6%. Baseline polymorphisms in NS3 or NS5A were less prevalent in GT2, with the exception of the common L/M31 polymorphism in NS5A. Among DAA-experienced GT1b-infected patients (30/32 daclatasvir plus asunaprevir-experienced patients), the baseline prevalence of NS3-D168E/T/V was 48.4%, that of NS5A-L31F/I/M/V was 81.3%, that of the NS5A P32deletion was 6.3%, and that of NS5A-Y93H was 59.4%. Common baseline polymorphisms in NS3 and/or NS5A had no impact on treatment outcomes in GT1- and GT2-infected patients; the impact on GT3-infected patients could not be assessed due to the enrollment of patients infected with diverse subtypes and the limited number of patients. The glecaprevir-pibrentasvir combination regimen allows a simplified treatment option without the need for HCV subtyping or baseline resistance testing for DAA-naive GT1- or GT2-infected patients. (The CERTAIN-1 and CERTAIN-2 studies have been registered at ClinicalTrials.gov under identifiers NCT02707952 and NCT02723084, respectively.).

Integrated Resistance Analysis of CERTAIN-1 and CERTAIN-2 Studies in Hepatitis C Virus-Infected Patients Receiving Glecaprevir and Pibrentasvir in Japan

Glecaprevir and pibrentasvir are hepatitis C virus (HCV) pangenotypic inhibitors targeting NS3/4A protease and NS5A, respectively. This once-daily, fixed-dose combination regimen demonstrated high sustained virologic response 12 weeks postdosing (SVR₁₂) rates in CERTAIN-1 and CERTAIN-2 studies in Japanese HCV-infected patients, with a low virologic failure rate (1.2%). There were no virologic failures among direct-acting antiviral (DAA)-treatment-naive genotype 1a (GT1a) (n = 4)-, GT1b (n = 128)-, and GT2 (n = 97)-infected noncirrhotic patients treated for 8 weeks or among GT1b (n = 38)- or GT2 (n = 20)-infected patients with compensated cirrhosis treated for 12 weeks. Two of 33 DAA-experienced and 2 of 12 GT3-infected patients treated for 12 weeks experienced virologic failure. Pooled resistance analysis, grouped by HCV subtype, treatment duration, prior treatment experience, and cirrhosis status, was conducted. Among DAA-naive GT1b-infected patients, the baseline prevalence of NS3-D168E was 1.2%, that of NS5A-L31M was 3.6%, and that of NS5A-Y93H was 17.6%. Baseline polymorphisms in NS3 or NS5A were less prevalent in GT2, with the exception of the common L/M31 polymorphism in NS5A. Among DAA-experienced GT1b-infected patients (30/32 daclatasvir plus asunaprevir-experienced patients), the baseline prevalence of NS3-D168E/T/V was 48.4%, that of NS5A-L31F/I/M/V was 81.3%, that of the NS5A P32deletion was 6.3%, and that of NS5A-Y93H was 59.4%. Common baseline polymorphisms in NS3 and/or NS5A had no impact on treatment outcomes in GT1- and GT2-infected patients; the impact on GT3-infected patients could not be assessed due to the enrollment of patients infected with diverse subtypes and the limited number of patients. The glecaprevir-pibrentasvir combination regimen allows a simplified treatment option without the need for HCV subtyping or baseline resistance testing for DAA-naive GT1- or GT2-infected patients. (The CERTAIN-1 and CERTAIN-2 studies have been registered at ClinicalTrials.gov under identifiers NCT02707952 and NCT02723084, respectively.).

Glecaprevir-Pibrentasvir for 8 or 12 Weeks in HCV Genotype 1 or 3 Infection

BACKGROUND

Glecaprevir and pibrentasvir are direct-acting antiviral agents with pangenotypic activity and a high barrier to resistance. We evaluated the efficacy and safety of 8-week and 12-week courses of treatment with 300 mg of glecaprevir plus 120 mg of pibrentasvir in patients without cirrhosis who had hepatitis C virus (HCV) genotype 1 or 3 infection.

METHODS

We conducted two phase 3, randomized, open-label, multicenter trials. Patients with genotype 1 infection were randomly assigned in a 1:1 ratio to receive once-daily glecaprevir-pibrentasvir for either 8 or 12 weeks. Patients with genotype 3 infection were randomly assigned in a 2:1 ratio to receive 12 weeks of treatment with either glecaprevir-pibrentasvir or sofosbuvir-daclatasvir. Additional patients with genotype 3 infection were subsequently enrolled and nonrandomly assigned to receive 8 weeks of treatment with glecaprevir-pibrentasvir. The primary end point was the rate of sustained virologic response 12 weeks after the end of treatment.

RESULTS

In total, 1208 patients were treated. The rate of sustained virologic response at 12 weeks among genotype 1-infected patients was 99.1% (95% confidence interval [CI], 98 to 100) in the 8-week group and 99.7% (95% CI, 99 to 100) in the 12-week group. Genotype 3-infected patients who were treated for 12 weeks had a rate of sustained virologic response at 12 weeks of 95% (95% CI, 93 to 98; 222 of 233 patients) with glecaprevir-pibrentasvir and 97% (95% CI, 93 to 99.9; 111 of 115) with sofosbuvir-daclatasvir; 8 weeks of treatment with glecaprevir-pibrentasvir yielded a rate of 95% (95% CI, 91 to 98; 149 of 157 patients). Adverse events led to discontinuation of treatment in no more than 1% of patients in any treatment group.

CONCLUSIONS

Once-daily treatment with glecaprevir-pibrentasvir for either 8 weeks or 12 weeks achieved high rates of sustained virologic response among patients with HCV genotype 1 or 3 infection who did not have cirrhosis. (Funded by AbbVie; ENDURANCE-1 and ENDURANCE-3 ClinicalTrials.gov numbers, NCT02604017 and NCT02640157 .).

The Effect of Shorter Treatment Regimens for Hepatitis C on Population Health and Under Fixed Budgets

Background

Direct acting antiviral hepatitis C virus (HCV) therapies are highly effective but costly. Wider adoption of an 8-week ledipasvir/sofosbuvir treatment regimen could result in significant savings, but may be less efficacious compared with a 12-week regimen. We evaluated outcomes under a constrained budget and cost-effectiveness of 8 vs 12 weeks of therapy in treatment-naïve, noncirrhotic, genotype 1 HCV-infected black and nonblack individuals and considered scenarios of IL28B and NS5A resistance testing to determine treatment duration in sensitivity analyses.

Methods

We developed a decision tree to use in conjunction with Monte Carlo simulation to investigate the cost-effectiveness of recommended treatment durations and the population health effect of these strategies given a constrained budget. Outcomes included the total number of individuals treated and attaining sustained virologic response (SVR) given a constrained budget and incremental cost-effectiveness ratios.

Results

We found that treating eligible (treatment-naïve, noncirrhotic, HCV-RNA <6 million copies) individuals with 8 weeks rather than 12 weeks of therapy was cost-effective and allowed for 50% more individuals to attain SVR given a constrained budget among both black and nonblack individuals, and our results suggested that NS5A resistance testing is cost-effective.

Conclusions

Eight-week therapy provides good value, and wider adoption of shorter treatment could allow more individuals to attain SVR on the population level given a constrained budget. This analysis provides an evidence base to justify movement of the 8-week regimen to the preferred regimen list for appropriate patients in the HCV treatment guidelines and suggests expanding that recommendation to black patients in settings where cost and relapse trade-offs are considered.

Retreatment Options Following HCV Direct Acting Antiviral Failure

Despite the excellent efficacy of direct acting antivirals (DAA) for hepatitis C virus (HCV), treatment failures do occur. Until recently, retreatment decisions after DAA failure were influenced by the number of available agents, concerns about HCV drug resistance, and lack of data regarding retreatment. Recommended treatment approaches previously depended on limited clinical trials and expert opinion. In this article, we review the current state of the evidence for HCV retreatment after DAA failure. Based on recent clinical trial data, most patients who fail HCV treatment with DAA agents now have excellent retreatment options. While some patients may benefit from resistance testing after DAA therapy failure to select the optimal treatment and duration, newly approved salvage therapies are not significantly impacted by common mutations and have been approved by the Food and Drug Administration for HCV retreatment without regard for the presence of resistance associated substitutions. While prior retreatment efforts were limited to longer courses of therapy, the addition of ribavirin, or novel combinations of approved therapies based on expert guidance, current DAA options make HCV retreatment in the DAA era more streamlined and evidence-based.

Changes in the epidemiology and distribution of the hepatitis C virus genotypes in North-Eastern Spain over the last 35 years

BACKGROUND

Genotypic distribution and epidemiology of HCV infection in Western Europe countries has changed over the last decades.

AIM

To establish the local genotypic profile and characterize the associated demographic variables.

MATERIAL AND METHOD

All the genotyping from 1988 to 2015 were considered. Associated demographic variables were included in logistic regression models. Genotyping was carried out with updated commercial kits.

RESULTS

Genotype 1b was the most prevalent (42.4%) followed by 1a (22.5%), 3 (18.6%), 4 (10.6%) and 2 (4.6%). The prevalence of 1a was higher in males, in patients younger than 45 and in intravenous drug users (IDU). 1b was more frequent in older than 45, with transfusion-associated and parenteral/nosocomial infections and in immigrants from Eastern Europe. Genotype 2 was highly prevalent in the postransfusional route (54.9%). Genotype 3 prevalence was high in males, in patients younger than 45, in IDU (69.3%) and in Asian and Eastern European immigrants. Genotype 4 was high in males, in patients younger than 45, and in IDU (63.5%). 1a, 3, 4 were the most prevalent genotypes in HIV-coinfected patients. There was a significant decline in genotype 1b and an increase in genotypes 3 and 4 over time.

CONCLUSIONS

There has been a decline of genotype 1b, associated with transfusion or parenteral/nosocomial infections, and increases in the prevalence of genotypes 1a, 3 and 4 associated with male gender and IDU, now the most prevalent infection route. Immigration contributed with genotype 2 infections from Africa and genotype 1b and 3 infections from Eastern Europe and Asia.

Respondent-driven sampling for identification of HIV- and HCV-infected people who inject drugs and men who have sex with men in India: A cross-sectional, community-based analysis

BACKGROUND

A major barrier to achieving ambitious targets for global control of HIV and hepatitis C virus (HCV) is low levels of awareness of infection among key populations such as men who have sex with men (MSM) and people who inject drugs (PWID). We explored the potential of a strategy routinely used for surveillance in these groups, respondent-driven sampling (RDS), to be used as an intervention to identify HIV- and HCV-infected PWID and MSM who are unaware of their status and those who are viremic across 26 Indian cities at various epidemic stages.

METHODS AND FINDINGS

Data were collected as part of the baseline assessment of an ongoing cluster-randomized trial. RDS was used to accrue participants at 27 sites (15 PWID sites and 12 MSM sites) selected to reflect varying stages of the HIV epidemic among MSM and PWID in India. A total of 56 seeds recruited a sample of 26,447 persons (approximately 1,000 participants per site) between October 1, 2012, and December 19, 2013. Across MSM sites (n = 11,997), the median age was 25 years and the median number of lifetime male partners was 8. Across PWID sites (n = 14,450), 92.4% were male, the median age was 30 years, and 87.5% reported injection in the prior 6 months. RDS identified 4,051 HIV-infected persons, of whom 2,325 (57.4%) were unaware of their HIV infection and 2,816 (69.5%) were HIV viremic. It also identified 5,777 HCV-infected persons, of whom 5,337 (92.4%) were unaware that they were infected with HCV and 4,728 (81.8%) were viremic. In the overall sample (both MSM and PWID), the prevalence of HIV-infected persons who were unaware of their status increased with sampling depth, from 7.9% in participants recruited in waves 1 through 5 to 12.8% among those recruited in waves 26 and above (p-value for trend < 0.001). The overall detection rate of people unaware of their HIV infection was 0.5 persons per day, and the detection rate of HIV-infected persons with viremia (regardless of their awareness status) was 0.7 per day. The detection rate of HIV viremic individuals was positively associated with underlying HIV prevalence and the prevalence of HIV viremia (linear regression coefficient per 1-percentage-point increase in prevalence: 0.05 and 0.07, respectively). The median detection rate of PWID who were unaware of their HCV infection was 2.5 per day. The cost of identifying 1 unaware HIV-infected individual ranged from US$51 to US$2,072 across PWID sites and from US$189 to US$5,367 across MSM sites. The mean additional cost of identifying 1 unaware HCV-infected PWID was US$13 (site range: US$7-US$140). Limitations of the study include the exclusivity of study sites to India, lack of prior HIV/HCV diagnosis confirmation with clinic records, and lack of cost data from other case-finding approaches commonly used in India.

CONCLUSIONS

In this study, RDS was able to rapidly identify at nominal cost a substantial number of unaware and viremic HIV-infected and HCV-infected individuals who were currently not being reached by existing programs and who were at high risk for transmission. Combining RDS (or other network-driven recruitment approaches) with strategies focused on linkage to care, particularly in high-burden settings, may be a viable option for achieving the 90-90-90 targets in key populations in resource-limited settings.

Direct antiviral agents (DAAs) - A new age in the treatment of hepatitis C virus infection

Hepatitis C virus (HCV) is a global health problem, because infection frequently leads to chronic hepatitis C eventually progressing to liver cirrhosis and liver cancer. Improved insights into the HCV replication cycle and the role of HCV non-structural proteins have recently enabled to identify drugs directly acting on specific HCV target structures. Agents from three drug classes have been developed and approved by the health authorities. Combinations of two or more drugs from different classes achieve high (>90%) HCV clearance rates and are well tolerated. This interferon-free DAA (direct antiviral agent) therapy has revolutionized antiviral therapy in hepatitis C so that successful hepatitis C treatment can be offered to virtually all patients irrespective of their co-morbidity. This review provides an overview over currently approved regimens and outlines their use in clinical practice. In addition potential short-comings of the current therapeutic options such as drug-drug interactions and selection of viral resistance are addressed. DAA combination therapy has the potential to obtain global control over hepatitis C. However, easy access to DAAs, availability of reliable HCV diagnostics, and affordable costs remain still important goals, which must be reached to globally eliminate hepatitis C.

No Clinically Relevant Drug-Drug Interactions between Methadone or Buprenorphine-Naloxone and Antiviral Combination Glecaprevir and Pibrentasvir

The combination of glecaprevir (formerly ABT-493), a nonstructural protein 3/4A (NS3/4A) protease inhibitor, and pibrentasvir (formerly ABT-530), an NS5A protein inhibitor, is being developed as treatment for HCV genotype 1 to 6 infection. The pharmacokinetics, pharmacodynamics, safety, and tolerability of methadone or buprenorphine-naloxone when coadministered with the glecaprevir-pibrentasvir combination in HCV-negative subjects on stable opioid maintenance therapy were investigated in a phase 1, single-center, two-arm, multiple-dose, open-label sequential study. Subjects received methadone (arm 1) or buprenorphine-naloxone (arm 2) once daily (QD) per their existing individual prescriptions alone (days 1 to 9) and then in combination with glecaprevir at 300 mg QD and pibrentasvir at 120 mg QD (days 10 to 16) each morning. Dose-normalized exposures were similar with and without glecaprevir and pibrentasvir for (R)- and (S)-methadone (≤5% difference) and for buprenorphine and naloxone (≤24% difference); the norbuprenorphine area under the curve was 30% higher with glecaprevir and pibrentasvir, consistent with maximum and trough plasma concentrations that increased by 21% to 25%. No changes in pupil response, short opiate withdrawal scale score, or desire for drugs questionnaire were observed when glecaprevir and pibrentasvir were added to methadone or buprenorphine-naloxone therapy. No dose adjustment is required when glecaprevir and pibrentasvir are coadministered with methadone or buprenorphine-naloxone.

Treatment of hepatitis C with new fixed dose combinations

INTRODUCTION

The advent of oral direct-acting antivirals (DAA) has revolutionized the hepatitis C virus (HCV) therapeutic landscape providing cure rates over 90%. However, a subset of patients remains at higher risk for treatment failure, including those infected with: i) genotype 3 and cirrhosis; ii) resistance-associated substitutions (RAS) occurring either as natural polymorphisms or selected after prior DAA failure; and iii) poor drug adherence associated with social disabilities (homeless, psychiatric illnesses, injection drug use, alcoholism, etc.). Whereas discovery of new DAA with increased antiviral activity across all genotypes and over RAS may enhance efficacy, development of fixed dose combinations (FDC) may be the best way to improve drug adherence in difficult-to-treat HCV populations. Areas covered: Three FDC regimens are in the last steps of clinical development for treating hepatitis C. Two distinct nucleotide analogues that inhibit the HCV polymerase, sofosbuvir and uprifosbuvir, are part of the FDC from Gilead and Merck, respectively. The AbbVie dual FDC does not include a polymerase inhibitor. All three new FDC include second-generation NS3 protease inhibitors and NS5A inhibitors active across all HCV genotypes and over common RAS. Expert opinion: Hepatitis C cure rates over 95% are expected with all three next-coming DAA, even in the most difficult-to-treat and/or cure patient populations. These regimens would be particularly needed for the growing number of prior DAA failures. Co-formulations and 8-week shorter treatment lengths will help to overcome drug adherence challenges in certain populations.