Efficacy of an interferon- and ribavirin-free regimen of daclatasvir, asunaprevir, and BMS-791325 in treatment-naive patients with HCV genotype 1 infection

Machine Learning Model Validated to Predict Outcomes of Liver Transplantation Recipients with Hepatitis C: The Romanian National Transplant Agency Cohort Experience

BACKGROUND AND OBJECTIVES

In the early period after liver transplantation, patients are exposed to a high rate of complications and several scores are currently available to predict adverse postoperative outcomes. However, an ideal, universally accepted and validated score to predict adverse events in liver transplant recipients with hepatitis C is lacking. Therefore, we aimed to establish and validate a machine learning (ML) model to predict short-term outcomes of hepatitis C patients who underwent liver transplantation.

MATERIALS AND METHODS

We conducted a retrospective observational two-center cohort study involving hepatitis C patients who underwent liver transplantation. Based on clinical and laboratory parameters, the dataset was used to train a deep-learning model for predicting short-term postoperative complications (within one month following liver transplantation). Adverse events prediction in the postoperative setting was the primary study outcome.

RESULTS

A total of 90 liver transplant recipients with hepatitis C were enrolled in the present study, 80 patients in the training cohort and ten in the validation cohort, respectively. The age range of the participants was 12-68 years, 51 (56,7%) were male, and 39 (43.3%) were female. Throughout the 85 training epochs, the model achieved a very good performance, with the accuracy ranging between 99.76% and 100%. After testing the model on the validation set, the deep-learning classifier confirmed the performance in predicting postoperative complications, achieving an accuracy of 100% on unseen data.

CONCLUSIONS

We successfully developed a ML model to predict postoperative complications following liver transplantation in hepatitis C patients. The model demonstrated an excellent performance for accurate adverse event prediction. Consequently, the present study constitutes the foundation for careful and non-invasive identification of high-risk patients who might benefit from a more intensive postoperative monitoring strategy.

Required concentration index quantifies effective drug combinations against hepatitis C virus infection

Successful clinical drug development requires rational design of combination treatments based on preclinical data. Anti-hepatitis C virus (HCV) drugs exhibit significant diversity in antiviral effect. Dose-response assessments can be used to determine parameters profiling the diverse antiviral effect during combination treatment. In the current study, a combined experimental and mathematical approaches were used to compare and score different combinations of anti-HCV treatments. A “required concentration index” was generated and used to rank the antiviral profile of possible double- and triple-drug combinations against HCV genotype 1b and 2a. Rankings varied based on target HCV genotype. Interestingly, multidrug (double and triple) treatment not only augmented antiviral activity, but also reduced genotype-specific efficacy, suggesting another advantage of multidrug treatment. The current study provides a quantitative method for profiling drug combinations against viral genotypes, to better inform clinical drug development.

Efficacy and safety of a fixed dose combination tablet of asunaprevir + beclabuvir + daclatasvir for the treatment of Hepatitis C

Introduction: Hepatitis C virus (HCV) is estimated to infect approximately 70 million people worldwide. If left untreated, chronic infection can progress to cirrhosis, liver failure or hepatocellular carcinoma. The advent of new direct-acting antivirals (DAA) has revolutionized patients' chances of treatment and viral elimination. Currently, several DAA options are available on the market.Areas covered: This review focuses on the pharmacokinetics, efficacy, tolerability and safety profile of DCV-TRIO, a twice-daily fixed-dose combination of daclatasvir, asunaprevir and beclabuvir approved in Japan for the treatment of genotype 1 HCV infection.Expert opinion: The DCV-TRIO combination achieved good response rates in genotype 1 patients (SVR12 ≥ 95% in naïve subtype 1b), independently from IL28B genotype, cirrhotic status and prior interferon exposure. On the other hand, unsatisfying response rates were reported in DAA-experienced patients and the risk of RAS selection should not be underestimated. Moreover, DCV-TRIO lacks differentiation from its earlier-launched DAA rivals, presents an inconvenient twice-daily dosing schedule and is not recommended in patients with advanced liver and kidney disease. All these drawbacks considerably limit its effective commercial potential. However, it can be a therapeutic option against HCV in tailored approaches according to the needs of different markets across the world.Abbreviations AE: adverse event; ALT: alanine aminotransferase; AST: aspartate aminotransferase; ASV: asunaprevir; AUC: area under the curve; BCRP: Breast Cancer Resistance Protein; BCV: boceprevir; BID: bis in die; CI: confidence intervals; CLcr: creatinine clearance; DAA: direct acting antivirals; DCV: daclatasvir; EC50: Half maximal effective concentration; GT: genotype; HCV: Hepatitis C virus; IFN: Interferon; NHL: non-Hodgkin lymphoma; OATP: Organic anion transporting polypeptides; OR: odds ratio; P-gp: P-glycoprotein; PK: pharmacokinetics; QD: quo die; RAS: resistance-associated substitutions; SVR: sustained virological response; USD: Unites States dollar.

Real-world virological efficacy and safety of daclatasvir/asunaprevir/beclabuvir in patients with chronic hepatitis C virus genotype 1 infection in Japan

BACKGROUND

The virological efficacy and safety of the direct-acting antiviral (DAA) regimen consisting of daclatasvir, asunaprevir, and beclabuvir (DCV/ASV/BCV) for patients chronically infected with hepatitis C virus (HCV) genotype 1 have not been previously evaluated in Japanese real-world settings.

METHODS

In a Japanese nationwide multicenter study, the rate of sustained virologic response (SVR) and safety were analyzed in 91 patients who started the DCV/ASV/BCV regimen between November 2016 and July 2017. SVR rates were compared based on baseline patient characteristics.

RESULTS

More than 60% of patients had a history of failure to achieve SVR with interferon (IFN)-free DAA therapy. Overall, 50 of 91 patients (54.9%) achieved SVR. Multivariate analysis identified a history of failure with IFN-free DAA therapy and pretreatment HCV RNA levels as factors significantly associated with treatment failure. Whereas the SVR rate in patients without a history of IFN-free DAA therapy was 91.7% (33 of 36 patients), it was only 30.9% (17 of 55 patients) among patients with a history of IFN-free DAA therapy. The rate of discontinuation due to an adverse event was 4.4%.

CONCLUSIONS

Many patients treated with the DCV/ASV/BCV regimen have a history of a failure to achieve SVR with previous IFN-free DAA therapy. SVR rate was not as high as that in pre-approval clinical trial of this regimen in IFN-free DAA-naïve patients. In addition, most patients with a history of failure with IFN-free DAA therapy, particularly the DCV/ASV regimen, showed resistance to this regimen.

Efficacy and safety of glecaprevir/pibrentasvir for chronic hepatitis C virus genotypes 1-6 infection: A systematic review and meta-analysis

This systematic review and meta-analysis investigated the efficacy and safety of glecaprevir and pibrentasvir (G/P) for chronic hepatitis C virus (HCV) infection. Pubmed, Embase, Cochrane Library and Scopus were searched to identify relevant studies through August 2018. Data from eligible studies were pooled and sustained virological response rates at 12 weeks' post-treatment (SVR12) were calculated. Thirteen studies with 3082 patients were included and the overall SVR12 rate was 97.8%. The SVR12 rates of subgroups were: G/P 300 mg/120 mg and 200 mg/120 mg: 97.9% and 98.3%; HCV genotype (GT)1, GT2, GT3 and GT4-6: 99.8%, 99.2%, 96.1% and 100%; G/P and G/P plus ribavirin (RBV): 97.9% and 98.2%; G/P (300 mg/120 mg) for 8 weeks, 12 weeks and 16 weeks: 98.8%, 98.5% and 95.6%; treatment-naïve and treatment-experienced patients: 96.7% and 98.3%; patients without and with compensated cirrhosis: 99.4% and 98.8%; patients without and with human immunodeficiency virus (HIV) co-infection: 97.8% and 99.4%; and patients without and with severe renal impairment (SRI): 97.8% and 99.4%. Virological failure and relapse and serious drug-related adverse events were rare. These results indicate that 8- or 12-week G/P treatment achieved high SVR12 rates in HCV GTs 1-6 patients without or with compensated cirrhosis, with good safety profiles, irrespective of dose, RBV use, treatment-experience, HIV co-infection and renal impairment. Due to the limited number of evaluated patients with GT3 infection, further studies are needed to define optimal treatment duration for GT3 cirrhosis patients and patients with prior treatment experience of direct-acting antivirals.

Restoration of HCV-Specific Immune Responses with Antiviral Therapy: A Case for DAA Treatment in Acute HCV Infection

Worldwide, 71 million individuals are chronically infected with Hepatitis C Virus (HCV). Chronic HCV infection can lead to potentially fatal outcomes including liver cirrhosis and hepatocellular carcinoma. HCV-specific immune responses play a major role in viral control and may explain why approximately 20% of infections are spontaneously cleared before the establishment of chronicity. Chronic infection, associated with prolonged antigen exposure, leads to immune exhaustion of HCV-specific T cells. These exhausted T cells are unable to control the viral infection. Before the introduction of direct acting antivirals (DAAs), interferon (IFN)-based therapies demonstrated successful clearance of viral infection in approximately 50% of treated patients. New effective and well-tolerated DAAs lead to a sustained virological response (SVR) in more than 95% of patients regardless of viral genotype. Researchers have investigated whether treatment, and the subsequent elimination of HCV antigen, can reverse this HCV-induced exhausted phenotype. Here we review literature exploring the restoration of HCV-specific immune responses following antiviral therapy, both IFN and DAA-based regimens. IFN treatment during acute HCV infection results in greater immune restoration than IFN treatment of chronically infected patients. Immune restoration data following DAA treatment in chronically HCV infected patients shows varied results but suggests that DAA treatment may lead to partial restoration that could be improved with earlier administration. Future research should investigate immune restoration following DAA therapies administered during acute HCV infection.

A novel, potent, and orally bioavailable thiazole HCV NS5A inhibitor for the treatment of hepatitis C virus

A medicinal chemistry program based on the small-molecule HCV NS5A inhibitor daclatasvir has led to the discovery of dimeric phenylthiazole compound 8, a novel and potent HCV NS5A inhibitor. The subsequent SAR studies and optimization revealed that the cycloalkyl amide derivatives 27a-29a exhibited superior potency against GT1b with GT1b EC₅₀ values at picomolar concentration. Interestingly, high diastereospecificity for HCV inhibition was observed in this class with the (1R,2S,1'R,2'S) diastereomer displaying the highest GT1b inhibitory activity. The best inhibitor 27a was found to be 3-fold more potent (GT1b EC₅₀ = 0.003 nM) than daclatasvir (GT1b EC₅₀ = 0.009 nM) against GT1b, and no detectable in vitro cytotoxicity was observed (CC₅₀ > 50 μM). Pharmacokinetic studies demonstrated that compound 27a had an excellent pharmacokinetic profiles with a superior oral exposure and desired bioavailability after oral administration in both rats and dogs, and therefore it was selected as a developmental candidate for the treatment of HCV infection.

A Stability-Indicating UPLC Method for the Determination of Potential Impurities and Its Mass by a New QDa Mass Detector in Daclatasvir Drug Used to Treat Hepatitis C Infection

A stability-indicating ultraperformance liquid chromatographic method has been developed for the quantitative determination of degradation products and process-related impurities of daclatasvir in a pharmaceutical dosage form. Chromatographic separation was achieved on a polar Waters ACQUITY BEH phenyl 100 × 2.1 mm, 1.7-μm column using the gradient program consisting of mobile phase A: 0.03 M sodium perchlorate with 0.002 M of 1-octanesulfonic acid sodium salt (pH 2.5 buffer) and mobile phase B: 0.03 M sodium perchlorate with 0.02 M of 1-octanesulfonic acid sodium salt (pH 2.5 buffer) with acetonitrile in the ratio of 20:80% v/v. A flow rate of 0.4 mL/min is maintained under ultraviolet detection at 305 nm. The run time was 15 min, within which daclatasvir, its related impurities and unknown degradants were well resolved. The method was found to produce symmetric and sharp peaks with good separation between process-related impurities and degradation impurities. Samples were subjected to hydrolysis (acid and base), oxidative, photolytic and thermal stress conditions to prove the stability-indicating nature of the method. The unknown degradation products were identified by PDA/QDa mass detector. This mass spectrum reveals protonated molecular ion peaks [M + H]+ at m/z DP1-582.4 in acid and base hydrolyses and m/z DP2-778.5 in peroxide hydrolysis. The method was validated in terms of specificity, precision, linearity, accuracy, limit of detection, limit of quantification and robustness as per ICH guidelines.

Exposure-Response Analysis for Efficacy of Daclatasvir, Asunaprevir, and Beclabuvir Combinations in HCV-Infected Patients

The combination regimen of daclatasvir, asunaprevir, and beclabuvir (3DAA regimen) was developed as a fixed-dose combination for the treatment of hepatitis C virus (HCV) infection in Japan. The objectives of this analysis were to characterize the relationship between drug exposure and sustained virologic response at posttreatment week 12 (SVR12) in HCV-infected subjects and to evaluate the impact of demographic covariates and clinical factors on the exposure-response (E-R) relationship. The E-R efficacy analysis was performed with data from phase 2 and phase 3 studies in HCV-infected subjects treated with the 3DAA regimen. The relationship between the probability of achieving SVR12 and exposure to daclatasvir, asunaprevir, and beclabuvir was described using a logistic regression model and included assessments of the potential covariate effects. The impacts of the covariates on the rate of SVR12 and interactions of covariates with the individual drug effects were tested. The final model for SVR12 included effects of non-genotype-1a status, resistance-associated NS5A-Q30 substitution in genotype-1a subjects, and baseline RNA level on the intercept, and effect of prior peg-interferon failure on the beclabuvir slope. Sex, race, age, weight, fibrosis score, alanine transaminase, and cirrhosis status had no statistically significant impact on the rate of SVR12. The individual E-R relationships with each drug, were relatively flat, and the effects of exposure were not significant. With the exception of the NS5A-Q30 substitution in genotype-1a subjects, statistically significant covariate effects had little impact on SVR12 rates. Overall, the E-R model was developed that captured the high SVR12 rates and the effect of covariates for the 3DAA regimen in HCV-infected patients.

Population Pharmacokinetic Analysis of Daclatasvir, Asunaprevir, and Beclabuvir Combination in HCV-Infected Subjects

A fixed-dose combination of daclatasvir (pangenotypic NS5A inhibitor), asunaprevir (NS3/4A protease inhibitor), and beclabuvir (nonnucleoside NS5B inhibitor) was approved for hepatitis C virus treatment in Japan. The objectives of the analyses were to develop the daclatasvir, asunaprevir, and beclabuvir population pharmacokinetic models for the combination regimen. First, an original population pharmacokinetic model was developed using the data in non-Japanese hepatitis C virus-infected subjects. The model was subsequently updated after a phase 3 study in Japanese hepatitis C virus-infected subjects was available. A total of 11,382, 11,300, and 10,728 pharmacokinetic records from 1,228 subjects were included for daclatasvir, asunaprevir, and beclabuvir in the updated model, respectively. Daclatasvir and beclabuvir pharmacokinetics (PK) were described by a 1-compartment model with linear elimination and asunaprevir PK was described by 2-compartment model with linear elimination. Cirrhosis, baseline, and time-varying ALT were significant covariates on asunaprevir apparent oral clearance. Asian subjects had greater asunaprevir and beclabuvir exposures than white subjects. The effects of all covariates on daclatasvir PK were modest and not considered clinically significant. With the exception of race on asunaprevir and beclabuvir PK, no other parameters for daclatasvir, asunaprevir and beclabuvir population PK models were meaningfully impacted during the refinement with Japanese subjects.

Safety Exposure-Response Analysis for Daclatasvir, Asunaprevir, and Beclabuvir Combinations in HCV-Infected Subjects

The combination regimen of daclatasvir, asunaprevir, and beclabuvir has been developed for the treatment of hepatitis C virus infection. The objectives of this analysis were to characterize the relationship between the exposures of the daclatasvir, asunaprevir, and beclabuvir regimen and liver‐related laboratory elevations (Grade 3 or 4 alanine aminotransferase [ALT] and total bilirubin [Tbili]), and to evaluate the impact of selected covariates on the exposure‐response relationships. The exposure‐response analysis was performed with data from 1 phase 2 and 3 phase 3 studies in hepatitis C virus–infected subjects. The probability of liver‐related laboratory elevations were modeled using linear logistic regression. Selected covariates were tested using a forward‐addition and backward‐elimination approach. The final model for ALT elevation included Asian race, body weight in non‐Asian subjects, and asunaprevir exposure. The final model for Tbili elevation included Asian race, fibrosis score (F0‐F3 or F4) and asupanprevir exposure. Asian subjects had greater the Grade 3 or 4 ALT and Tbili elevation rates than non‐Asians. The Grade 3 or 4 ALT elevation rate increased with decreasing body weight in non‐Asian subjects. Subjects with F4 fibrosis score had a higher rate of Grade 3 or 4 Tbili elevation compared to subjects with F0 to F3 fibrosis score. Higher asunaprevir exposure was associated with increases in Grade 3 or 4 ALT and Tbili elevation rates; however, the impact on the ALT elevation was not clinically relevant and the effect on Tbili elevation was smaller than the other significant covariates.

Evolution of efficacious pangenotypic hepatitis C virus therapies

Hepatitis C compromises the quality of life of more than 350 million individuals worldwide. Over the last decade, therapeutic regimens for treating hepatitis C virus (HCV) infections have undergone rapid advancements. Initially, structure-based drug design was used to develop molecules that inhibit viral enzymes. Subsequently, establishment of cell-based replicon systems enabled investigations into various stages of HCV life cycle including its entry, replication, translation, and assembly, as well as role of host proteins. Collectively, these approaches have facilitated identification of important molecules that are deemed essential for HCV life cycle. The expanded set of putative virus and host-encoded targets has brought us one step closer to developing robust strategies for efficacious, pangenotypic, and well-tolerated medicines against HCV. Herein, we provide an overview of the development of various classes of virus and host-directed therapies that are currently in use along with others that are undergoing clinical evaluation.

Daclatasvir Plus Asunaprevir for the Treatment of Patients with Hepatitis C Virus Genotype 1b Infection: Real-World Efficacy, Changes in Liver Stiffness and Fibrosis Markers, and Safety

Background/Aims

The treatment with daclatasvir plus asunaprevir (DCV+ASV) is associated with potent antiviral effects in patients with genotype 1b hepatitis C virus (HCV) infection. We investigated the real-world efficacy, changes in liver stiffness and noninvasive fibrosis markers, and the safety of DCV+ASV treatment in Korean patients.

Methods

In total, 363 patients with chronic hepatitis C were treated with DCV+ASV between August 2015 and January 2017. Finally, we analyzed the data of 270 patients who were monitored for at least 12 weeks after the end of treatment.

Results

The mean age was 60.7 years, and females predominated (60.4%). Most patients (64.8%) were treatment-naïve, and 56 patients (20.7%) had cirrhosis. Two hundred fifty-seven (95.2%) and 251 (93.0%) patients achieved end-of-treatment responses and sustained virological responses at 12 weeks posttreatment (SVR12), respectively. The SVR12 rates were higher in patients who were <65 years of age, males, without cirrhosis and had lower HCV RNA levels. All LS values and fibrosis-4 and aspartate aminotransferase-to-platelet ratio index values declined from baseline to the time of assessment of SVR12.

Conclusions

The DCV+ASV therapy resulted in a high SVR12 and improved liver fibrosis; the treatment was well tolerated in patients with genotype 1b HCV infections.

Analysis of Host and Viral-Related Factors Associated to Direct Acting Antiviral Response in Hepatitis C Virus Patients

Hepatitis C virus (HCV) signifies an important health issue as it is a globally prevalent pathogen and poses a great threat to human health. Direct antiviral therapy became a landmark in treatment against chronic HCV infection as they have proven to increase sustained virological response (SVR) rate, provide shortened and simplified regimens. This study aimed to evaluate efficacy of Sofosbuvir and classify factors of treatment success and their function in therapy continuation decision. We studied host and viral factors in 310 patients who received Sofosbuvir (DAA) at a dose of 400 mg daily along with ribavirin 10 mg/kg body weight for 24 weeks and followed by 12 weeks after completion of treatment. A total of 302 patients (97.42%) showed end-of-treatment response. However, 8 patients (2.58%) were virological nonresponders and 286 patients (94.70%) achieved SVR. Among 310 HCV positive, the percentage of viral genotype 3-infected patients was 89.6%, whereas only 10.32% were affected by HCV genotype 1. Multivariable analysis showed that baseline HCV RNA (≤8 × 10⁶ IU/mL vs. >8 × 10⁶ IU/mL) [95% confidence interval (CI), odds ratio (OR) 3.0, 2.0 to 8.4; p = 0.004], age (<50 vs. ≥50 years) (95% CI, OR 1.9, 3.0 to 10.1; p = 0.03), liver texture (normal liver vs. coarse) are related to virological response. None of the patients included in the study has S282T substitution in NS5b of HCV. No significant difference in response was observed in patients with different genotypes of rs12979860. Liver texture, age, and viral load are predictors of SVR. In this real-life data no substitution of S282T in NS5b was observed related to failure of therapy. Oral Sofosbuvir generally has a high tolerance and can effortlessly beat the safety concerns of past regimens.

Suppression of Hepatitis C Virus Genome Replication and Particle Production by a Novel Diacylglycerol Acyltransferases Inhibitor

Diacylglycerol acyltransferases (DGATs) play a critical role in the biosynthesis of endogenous triglycerides (TGs) and formation of lipid droplets (LDs) in the liver. In particular, one member of DGATs, DGAT-1 was reported to be an essential host factor for the efficient production of hepatitis C virus (HCV) particles. By utilizing our previously characterized three different groups of twelve DGAT inhibitors, we found that one of the DGAT inhibitors, a 2-((4-adamantylphenoxy) methyl)-N-(furan-2-ylmethyl)-1H-benzo[d]imidazole-5-carboxam (10j) is a potent suppressor of both HCV genome replication and particle production. 10j was able to induce inhibition of these two critical viral functions in a mutually separate manner. Abrogation of the viral genome replication by 10j led to a significant reduction in the viral protein expression as well. Interestingly, we found that its antiviral effect did not depend on the reduction of TG biosynthesis by 10j. This suggests that the inhibitory activity of 10j against DGATs may not be directly related with its antiviral action.

Limitations of daclatasvir/asunaprevir plus beclabuvir treatment in cases of NS5A inhibitor treatment failure

Combined daclatasvir (DCV)/asunaprevir (ASV) plus beclabuvir (BCV) treatment shows a high virological response for genotype 1b chronic hepatitis C patients. However, its efficacy for patients for whom previous direct-acting antiviral (DAA) therapy failed is not known. We analysed the efficacy of DCV/ASV/BCV treatment for HCV-infected mice and chronic hepatitis patients. Human hepatocyte chimaeric mice were injected with serum samples obtained from either a DAA-naïve patient or a DCV/ASV treatment failure and were then treated with DCV/ASV alone or in combination with BCV for 4 weeks. DCV/ASV treatment successfully eliminated the virus in DAA-naïve-patient HCV-infected mice. DCV/ASV treatment failure HCV-infected mice developed viral breakthrough during DCV/ASV treatment, with the emergence of NS5A-L31V/Y93H HCV resistance-associated variants (RAVs) being observed by direct sequencing. DCV/ASV/BCV treatment inhibited viral breakthrough in NS5A-L31V/Y93H-mutated HCV-infected mice, but HCV relapsed with the emergence of NS5B-P495S variants after the cessation of the treatment. The efficacy of the triple therapy was also analysed in HCV-infected patients; one DAA-naïve patient and four prior DAA treatment failures were treated with 12 weeks of DCV/ASV/BCV therapy. Sustained virological response was achieved in a DAA-naïve patient and one of the DCV/ASV treatment failures through DCV/ASV/BCV therapy; however, HCV relapse occurred in the other patients with prior DCV/ASV and/or sofosbuvir/ledipasvir treatment failures. DCV/ASV/BCV therapy seems to have limited efficacy for patients with NS5A RAVs for whom prior DAA treatment has failed.

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.

Discovery of Beclabuvir: A Potent Allosteric Inhibitor of the Hepatitis C Virus Polymerase

The discovery of beclabuvir occurred through an iterative series of structure-activity relationship studies directed at the optimization of a novel class of indolobenzazepines. Within this research, a strategic decision to abandon a highly potent but physiochemically problematic series in favor of one of lower molecular weight and potency was key in the realization of the program’s objectives. Subsequent cycles of analog design incorporating progressive conformational constraints successfully addressed off-target liabilities and identified compounds with improved physiochemical profiles. Ultimately, a class of alkyl-bridged piperazine carboxamides was found to be of particular interest, and from this series, beclabuvir was identified as having superior antiviral, safety, and pharmacokinetic properties. The clinical evaluation of beclabuvir in combination with both the NS5A replication complex inhibitor daclatasvir and the NS3 protease inhibitor asunaprevir in a single, fixed-dose formulation (Ximency) resulted in the approval by the Japanese Pharmaceutical and Food Safety Bureau for its use in the treatment of patients infected with genotype 1 HCV.

Long-term follow-up of clinical trial patients treated for chronic HCV infection with daclatasvir-based regimens

BACKGROUND & AIMS

Daclatasvir has achieved high sustained virologic response (SVR) rates in diverse hepatitis C virus (HCV) populations. This study evaluated the long-term efficacy and safety of daclatasvir-based regimens administered during clinical studies.

METHODS

Patients enrolled within 6 months of parent study completion or protocol availability at the study sites. The primary objective was durability of SVR at follow-up Week 12 (SVR12). Secondary objectives included analysing HCV sequences in non-responders or responders who relapsed, and characterization of liver disease progression.

RESULTS

Between 24 February 2012 and 17 July 2015, this study enrolled and began following 1503 recipients of daclatasvir-based regimens (follow-up cut-off, 13 October 2015); 60% were male, 18% aged ≥65 years, 87% had genotype-1a (42%) or -1b (45%) infection, and 18% had cirrhosis. Median follow-up from parent study follow-up Week 12 was 111 (range, 11-246) weeks. 1329/1489 evaluable patients were SVR12 responders; 1316/1329 maintained SVR until their latest visit. Twelve responders relapsed by (n = 9) or after (n = 3) parent study follow-up Week 24; one was reinfected. Relapse occurred in 3/842 (0.4%) and 9/487 (2%) responders treated with interferon-free or interferon-containing regimens, respectively. Hepatic disease progression and new hepatocellular carcinoma were diagnosed in 15 and 23 patients, respectively. Among non-responders, emergent non-structural protein-5A (NS5A) and -3 (NS3) substitutions were replaced by wild-type sequences in 27/157 (17%) and 35/47 (74%) patients, respectively.

CONCLUSIONS

SVR12 was durable in 99% of recipients of daclatasvir-based regimens. Hepatic disease progression and new hepatocellular carcinoma were infrequent. Emergent NS5A substitutions persisted longer than NS3 substitutions among non-responders.

Usefulness of semiquantitative PCR-Invader assay for selecting candidates for daclatasvir plus asunaprevir combination therapy among patients with hepatitis C virus genotype 1b

AIMS

PCR-Invader is a highly sensitive assay for detecting non-structural protein 5A (NS5A) resistance-associated variants (RAVs) of hepatitis C virus (HCV). Here, we validated the accuracy of the semiquantitative PCR-Invader (SQ-PI) assay compared to direct sequencing (DS) for identifying NS5A RAVs, and we evaluated the treatment efficacy of daclatasvir plus asunaprevir (DCV + ASV) for patients judged to be non-positive for NS5A RAVs by SQ-PI.

METHODS

Detection rates of NS5A RAVs by SQ-PI and DS were compared for 204 patients with HCV genotype 1b. Patients with non-positive results for NS5A RAVs by SQ-PI were treated by DCV + ASV, and the efficacy of this treatment was examined.

RESULTS

All samples judged as negative for NS5A RAVs by SQ-PI were similarly judged by DS. However, 29.7% of samples judged as negative for Y93H by DS were judged as weakly positive or positive by SQ-PI. Among 108 patients who were judged as negative by SQ-PI and treated by DCV + ASV, rates of sustained virologic response at 24 weeks (SVR24) were 96.3% in intention-to-treat analysis and 99.0% in patients who completed treatment. Among patients who were weakly positive for Y93H on SQ-PI, the SVR24 rate was 95.0% (19/20). This rate was 100% (78/78) in patients who were negative for Y93H on SQ-PI and completed treatment.

CONCLUSION

Treatment efficacy of DCV + ASV was extremely high among patients who were non-positive for NS5A RAVs on SQ-PI, especially for patients with negative results.

Hepatitis C virus drug resistance associated substitutions and their clinical relevance: Update 2018

Nowadays, due to the development of potent Direct-Acting Antiviral Agents (DAAs) that specifically target NS3, NS5A and NS5B viral proteins, several new and highly efficacious options to treat chronic Hepatitis C virus (HCV) infection are available. The natural presence of resistance associated substitutions (RASs), as well as their rapid emergence during incomplete drug-pressure, are intrinsic characteristics of HCV that greatly affect treatment outcome and the chances to achieve a virolgical cure. To date, a high number of RASs in NS3, NS5A, and NS5B have been associated in vivo and/or in vitro with reduced susceptibility to DAAs, but no comprehensive RASs list is available. This review thus provides an updated, systematic overview of the role of RASs to currently approved DAAs or in phase II/III of clinical development against HCV-infection, discriminating their impact in different HCV-genotypes and DAAs, providing assistance for a fruitful use of HCV resistance testing in clinical practice.

Beclabuvir in combination with asunaprevir and daclatasvir for hepatitis C virus genotype 1 infection: A systematic review and meta-analysis

Daclatasvir, asunaprevir (ASV), and beclabuvir (BCV) are direct-acting antivirals (DAAs) for patients with hepatitis C virus genotype 1 infection. This systematic review and meta-analysis investigating the efficacy and safety of this three-drug combination in HCV genotype 1 infection. Eleven electronic search engines were searched for relevant publications. Studies were screened for eligibility and data was extracted. The outcomes were pooled as event rate and risk ratio (RR). The protocol was registered in PROSPERO (CRD42017054391). Among the included six studies, five studies were included for the meta-analysis (n = 1261). The three-drug combination showed a high response rate in naïve patients with sustained virologic response at week-12 posttreatment (SVR₁₂ ) rate = 95.7% (95%CI [93.8-97.1]) and no difference detected by adding ribavirin (RBV) (the pooled RR = 0.98, 95%CI [0.90-1.08], P = 0.70) or comparing with interferon-experienced patients (RR = 1.02, 95%CI [0.98-1.07], P = 0.31) regardless the genotype 1 subtypes or IL28B genotype. Treatment failure was minimal and showed no difference regarding the previous comparisons. Increasing the dose or the duration did not show a significant increase in the efficacy. In conclusion, this analysis showed high response rates in HCV genotype 1-infected patients treated with daclatasvir, ASV, and BCV irrespective of RBV use, prior interferon-based therapy, or restriction on non-cirrhotic patients, IL28B genotype, or baseline resistance-associated variants.

Efficacy of Interferon-Free Therapies for Chronic Hepatitis C: A Systematic Review of All Randomized Clinical Trials

BACKGROUND AND OBJECTIVES

Second-generation direct-acting antivirals (DAAs) have recently arisen as more effective and safer treatments for chronic hepatitis C. These drugs can be combined into treatments without interferon (IFN), and are therefore called IFN-free therapies.

OBJECTIVE

The objective of this study systematic review was to evaluate the efficacy of IFN-free therapies for the treatment of chronic hepatitis C, and thus increase the clinical evidence for these therapies.

METHODS

A systematic review was conducted in accordance with Cochrane Collaboration recommendations. A search was performed in six different electronic databases using 'clinical trials', 'hepatitis C' and 'interferon-free' as the main descriptors, and studies that conformed to the inclusion criteria had their data extracted, including study information, baseline characteristics, and efficacy outcomes (sustained virologic response, rapid virologic response, and virologic failure).

RESULTS

Sixty-four randomized clinical trials including 15 different therapies were included in a total of 15,731 patients infected with the hepatitis C virus, mostly with genotype 1, and mainly treated for 12 or 24 weeks. The sustained virologic response rate after 12 weeks of treatment was approximately 89%, while the virologic failure rate was below 5%.

CONCLUSIONS

Second-generation DAAs presented several advantages: virologic response values higher than the average achieved by previous IFN-based therapies, reduced treatment duration, and the possibility of different combinations of therapies to meet patient needs. Thus, IFN-free therapies appear to be valuable alternatives for the treatment of chronic hepatitis C.

[Revealing the characteristics of antiviral agents]

Rapid development of novel anti-hepatitis C virus (HCV) agents in recent years has greatly improved treatment outcomes. However, such rapid progress in anti-HCV treatment has not allowed us to fully argue the different characteristics of each anti-HCV agent, optimal multidrug combinations, and the selection of treatment enabling to efficiently eliminate drug resistant viruses. We here quantified the intrinsic antiviral effect of 15 anti-HCV agents either clinically available or under developmental phase using a cell culture system, and identified the parameters that represent the antiviral profile of drugs through mathematical analysis. A computer simulation that calculated the antiviral activity and the frequency of mutation rate under dual- and triple-multidrug treatment presented the argument for the advantage of multidrug treatments. In this review, we summarize the novel approaches to evaluate intrinsic antiviral efficacy of drugs by combining the virological and mathematical analyses.

Allosteric mechanism of cyclopropylindolobenzazepine inhibitors for HCV NS5B RdRp via dynamic correlation network analysis

HCV RNA dependent RNA polymerase (RdRp) nonstructural protein 5B (NS5B) is a major target against hepatitis C virus (HCV) for antiviral therapy. Recently discovered cyclopropylindolobenzazepine derivatives have been considered as the most potent for their ability to bind the thumb site 1 domain and allosterically inhibit HCV NS5B RdRp activity. However, the allosteric mechanism for these derivatives has not been clarified at the molecular level. In this study, fluctuation correlation networks were constructed based on all-atom molecular dynamics simulations to elucidate the allosteric mechanism. The fluctuation correlation networks between free and M2 bound NS5B are significantly different. Information can better transfer from the allosteric site to the catalytic site for bound NS5B than for free NS5B. Thus, the hypothesis of "binding induced allosteric regulation" is proposed to link the enzyme activation and inhibitor binding and then confirmed by the mutant network. Finally, one possible allosteric pathway was identified with the shortest path and evaluated by the perturbation of the network. These methods will be helpful to identify the allosteric pathway of other proteins and to design new drugs targeting the pathway.

Changes in renal function indices in cirrhotic chronic hepatitis C patients treated with sofosbuvir-containing regimens

This study aimed to explore changes in hepatic and renal function indices in chronic hepatitis C (CHC) patients treated with direct-acting antivirals (DAAs). Forty-three CHC patients treated with sofosbuvir (SOF)-containing regimens were enrolled. At the end of treatment, the estimated glomerular filtration rate (eGFR) level was significantly decreased and the serum creatinine (Scr) and uric acid (UA) levels were significantly increased compared with baseline levels (eGFR: 86.7 ± 20.4 vs 80.5 ± 21.3, P₀₁ = 0.005; Scr: 83.9 ± 19.1 vs 89.6 ± 21.1, P₀₁ < 0.001; UA: 323.7± 86.2 vs 358.5 ± 93.2, P₀₁ < 0.001); no significant improvements were observed at 24 w post-treatment (eGFR: 86.7 ± 20.4 vs 81.4 ± 18.6, P₀₂ = 0.013; Scr: 83.6 ± 17.9 vs 87.9 ± 18.3, P₀₂ = 0.014; UA: 320.8 ± 76.3 vs 349.3 ± 91.0, P₀₂ = 0.004). When the patients were grouped by liver conditions, non-cirrhotic patients and cirrhotic patients had decreased eGFR levels and increased Scr levels at the end of treatment; at 24 w post-treatment, the eGFR and Scr levels were significantly improved in non-cirrhotic patients (88.4 ± 21.7 vs 83.8 ± 18.5, P₀₂ = 0.142; 84.4 ± 20.4 vs 87.0 ± 16.9, P₀₂ = 0.088), while no obvious improvements were observed in cirrhotic patients (84.3 ± 18.7 vs 78.1 ± 18.6, P₀₂ = 0.002; 83.2 ± 17.7 vs 89.2 ± 20.6, P₀₂ = 0.006). Clinical physicians should closely monitor renal function in patients treated with SOF-containing regimens, especially in cirrhotic patients.

Discovery and preclinical development of dasabuvir for the treatment of hepatitis C infection

INTRODUCTION

Hepatitis C virus (HCV) is a leading cause of liver-related morbidity and mortality. Positively, the introduction of new directly-acting antivirals (DAAs) have led to dramatic improvements in response rates to antiviral therapy. Furthermore, newer generations of DAAs have demonstrated better safety profiles as well as efficacy than older generations. Current treatment recommendations are based on different combinations of DAAs. Current combination therapies rely on agents that target the different steps of viral replication by using different molecules from various DAAs families. Areas covered: In this review, the authors summarize data from of one of the recently developed NS5B polymerase inhibitors, dasabuvir, formerly known as ABT-333. Herein, the authors discuss the drug discovery data for dasabuvir including data from preclinical, toxicological resistance studies. The authors also review dasabuvir's clinical efficacy across various clinical challenges, in addition to its limitations in clinical practice. Expert opinion: Dasabuvir represents an important medical advance when used as a combination therapy for HCV. Unfortunately, it does present limitations like low genotypic coverage and further research is still required to address some of the lingering issues.

Current therapy for chronic hepatitis C: The role of direct-acting antivirals

One of the most exciting developments in antiviral research has been the discovery of the direct-acting antivirals (DAAs) that effectively cure chronic hepatitis C virus (HCV) infections. Based on more than 100 clinical trials and real-world studies, we provide a comprehensive overview of FDA-approved therapies and newly discovered anti-HCV agents with a special focus on drug efficacy, mechanisms of action, and safety. We show that HCV drug development has advanced in multiple aspects: (i) interferon-based regimens were replaced by interferon-free regimens; (ii) genotype-specific drugs evolved to drugs for all HCV genotypes; (iii) therapies based upon multiple pills per day were simplified to a single pill per day; (iv) drug potency increased from moderate (∼60%) to high (>90%) levels of sustained virologic responses; (v) treatment durations were shortened from 48 to 12 or 8 weeks; and (vi) therapies could be administered orally regardless of prior treatment history and cirrhotic status. However, despite these remarkable achievements made in HCV drug discovery, challenges remain in the management of difficult-to-treat patients.

•

HCV genotype-specific drugs evolve to pan-genotypic drugs.

•

Drug potency increases from moderate (∼60%) to high (>90%) levels of sustained virologic response.

•

Treatment durations are shortened from a 48-week to 12-week or 8-week period.

•

HCV therapies based upon multiple pills per day are simplified to a single pill per day.

•

HCV therapies are administered orally regardless of prior treatment history and cirrhotic status.

Functionalized triazines as potent HCV entry inhibitors

A series of potent and novel acylsulfonamide-bearing triazines were synthesized and the structure-activity relationships (SARs) as HCV entry inhibitors were evaluated. This acylsulfonamide series was derived from an early lead, 4-(4-(1-(4-chlorophenyl)cyclopropylamino)-6-(2,2,2-trifluoroethoxy)-1,3,5-triazin-2-ylamino)benzoic acid wherein the carboxylic acid was replaced with an acylsulfonamide moiety. This structural modification provided a class of compounds which projected an additional vector off the terminus of the acylsulfonamide functionality as a means to drive activity. This effort led to the discovery of potent analogues within this series that demonstrated sub-nanomolar EC₅₀ values in the HCV pseudotype particle (HCVpp) assay.

Quantifying antiviral activity optimizes drug combinations against hepatitis C virus infection

With the introduction of direct-acting antivirals (DAAs), treatment against hepatitis C virus (HCV) has significantly improved. To manage and control this worldwide infectious disease better, the "best" multidrug treatment is demanded based on scientific evidence. However, there is no method available that systematically quantifies and compares the antiviral efficacy and drug-resistance profiles of drug combinations. Based on experimental anti-HCV profiles in a cell culture system, we quantified the instantaneous inhibitory potential (IIP), which is the logarithm of the reduction in viral replication events, for both single drugs and multiple-drug combinations. From the calculated IIP of 15 anti-HCV drugs from different classes [telaprevir, danoprevir, asunaprevir, simeprevir, sofosbuvir (SOF), VX-222, dasabuvir, nesbuvir, tegobuvir, daclatasvir, ledipasvir, IFN-α, IFN-λ1, cyclosporin A, and SCY-635], we found that the nucleoside polymerase inhibitor SOF had one of the largest potentials to inhibit viral replication events. We also compared intrinsic antiviral activities of a panel of drug combinations. Our quantification analysis clearly indicated an advantage of triple-DAA treatments over double-DAA treatments, with triple-DAA treatments showing enhanced antiviral activity and a significantly lower probability for drug resistance to emerge at clinically relevant drug concentrations. Our framework provides quantitative information to consider in designing multidrug strategies before costly clinical trials.

Clinical Laboratory Testing in the Era of Directly Acting Antiviral Therapies for Hepatitis C

Directly acting antiviral (DAA) combination therapies for chronic hepatitis C virus (HCV) infection are highly effective, but treatment decisions remain complex. Laboratory testing is important to evaluate a range of viral, host, and pharmacological factors when considering HCV treatment, and patients must be monitored during and after therapy for safety and to assess the viral response. In this review, we discuss the laboratory tests relevant for the treatment of HCV infection in the era of DAA therapy, grouped according to viral and host factors.

A Potent, Selective, and Orally Bioavailable HCV NS5A Inhibitor for Treatment of Hepatitis C Virus: (S)-1-((R)-2-(Cyclopropanecarboxamido)-2-phenylacetyl)-N-(4-phenylthiazol-2-yl)pyrrolidine-2-carboxamide

Starting from the initial lead 4-phenylthiazole 18, a modest HCV inhibitor (EC₅₀ = 9440 nM), a series of structurally related thiazole derivatives has been identified as a novel chemical class of potent and selective HCV NS5A inhibitors. The introduction of a carboxamide group between the thiazole and pyrrolidine ring (42) of compound 18 resulted in a dramatic increase in activity (EC₅₀ = 0.92 nM). However, 42 showed only moderate pharmacokinetic properties and limited oral bioavalability of 18.7% in rats. Further optimization of the substituents at the 4-position of the thiazole ring and pyrrolidine nitrogen of the lead compound 42 led to the identification of compound 57, a highly potent and selective NS5A inhibitor of HCV (EC₅₀ = 4.6 nM), with greater therapeutic index (CC₅₀/EC₅₀ > 10000). Pharmacokinetic studies revealed that compound 57 had a superior oral exposure and desired bioavailability of 45% after oral administration in rats.

Efficacy and Safety of Daclatasvir in Hepatitis C: An Overview

Hepatitis C virus (HCV) infection is a growing public health concern, with 184 million people infected worldwide. During the past decade, interferon has been the backbone of HCV treatment, even though it remains far from ideal. The latest development of the new direct antivirals has drastically changed the treatment approach for chronic hepatitis C (CHC). Inhibitors of the HCV NS5A region have garnered remarkable interest among treating physicians, due to their high potency and favourable safety profile. In particular, treatment with daclatasvir (DCV) has yielded high rates of vriologic response in patients infected with genotype (Gt) 1 and Gt 3, when used in combination with other antivirals of a different class, such as sofosbuvir. Although few data are available for DCV treatment of the other Gts, the results in patients with Gt 2 and Gt 4 infection appear promising, as do those for unique patient populations. NS5A-resistant viral variants can pre-exist or emerge after treatment failure for the HCV NS5A inhibitors. Nonetheless, DCV-resistant viral variants continue to be sensitive to interferon and other classes of antivirals such as NS3/4A and NS5B inhibitors. Herein, we aimed to provide an overview of the current knowledge about DCV in the treatment of CHC.

Real world experience with pegylated interferon and ribavirin in hepatitis C genotype 1 population with favourable IL28B polymorphism

Background and aim: Conventional hepatitis C treatment using pegylated interferon (PEG-IFN) and ribavirin is associated with significant side effects. IL28B polymorphism can predict response to treatment, with CC genotype having a better response. ITPA gene deficiency protects against clinically significant anaemia induced by treatment. The purpose of this study was to determine IL28B polymorphism and ITPA variation among hepatitis C genotype 1 patients who have undergone therapy with PEG-IFN and ribavirin and their association with sustained viral response (SVR). Methods: All hepatitis C genotype 1 patients who had been treated with PEG-IFN and ribavirin over the past 10 years were identified by available medical records and were contacted by letter of invitation to participate in the study. Blood samples for IL28B and ITPA genotyping were obtained. Medical records were reviewed for verification of treatment response, development of anaemia and if treatment reduction was required during the treatment. Results: A total of 61 patients with hepatitis C genotype 1 were treated with PEG-IFN and ribavirin, of whom 42 agreed to participate in the study. Mean age was 45.6±12.9 years at time of treatment, and 83.3% of patients were males. Thirty-three (78.6%) had IL28B CC genotype, of whom 25 (75.8%) obtained SVR compared with only 3 of 9 (33.3%) non C/C genotype patients who achieved SVR (P=0.041). Eleven (26.1%) patients had ITPA AC genotype, and 30 (71.4%) had CC genotype. There was no statistically significant difference between ITPA AC and CC genotypes in predicting clinically significant anaemia (45.5% vs 63.3%, P=0.302). Even among patients who developed anaemia, 70.8% still managed to achieve SVR. Treatment reduction also had no impact on SVR. Conclusion: Hepatitis C genotype 1 patients should be informed of the response rate for treatment with PEG-IFN and ribavirin in a population with favourable IL28B genotype before consideration of newer therapeutic options.

Management of hepatitis C genotype 4 in the directly acting antivirals era

Genotype 4 chronic hepatitis C (G4 HCV) accounts for 13% of worldwide HCV infections; with 10 million people infected with the virus across the world. Up to the end of 2013, the only treatment option for G4 HCV was treatment with pegylated interferon and ribavirin for 24-48 weeks. Since late 2013, treatment of G4 HCV has been transformed by the licensing of many directly acting antiviral agents (DAA). It is an exciting time to be involved in the management of HCV generally and G4 particularly. Interferon-free DAA regimens are now a reality for G4 HCV. This review will highlight these developments and discuss the data behind the use of these drugs. It will also highlight future regimens that are likely to be available over the coming years.

APASL consensus statements and recommendation on treatment of hepatitis C

The Asian-Pacific Association for the Study of the Liver (APASL) convened an international working party on the "APASL consensus statements and recommendation on management of hepatitis C" in March, 2015, in order to revise "APASL consensus statements and management algorithms for hepatitis C virus infection (Hepatol Int 6:409-435, 2012)". The working party consisted of expert hepatologists from the Asian-Pacific region gathered at Istanbul Congress Center, Istanbul, Turkey on 13 March 2015. New data were presented, discussed and debated to draft a revision. Participants of the consensus meeting assessed the quality of cited studies. Finalized recommendations on treatment of hepatitis C are presented in this review.

Daclatasvir-based Treatment Regimens for Hepatitis C Virus Infection: A Systematic Review and Meta-Analysis

CONTEXT

Direct acting antivirals (DAAs) have recently emerged as a promising therapeutic regimen for the treatment of hepatitis C virus (HCV) infection, which is a major public health problem. Among the known DAAs, daclatasvir (DCV), an inhibitor of the non-structural 5A protein, has been used in combination with several drugs for treatment of infection with HCV of different genotypes under different conditions. We conducted a systematic review and meta-analysis of combination therapy with DCV.

EVIDENCE ACQUISITION

We performed a systematic search in PubMed, Scopus, Science Direct and Web of Science with appropriate keywords for DCV. Studies that evaluated any regimen containing DCV and reported the sustained virological response (SVR) 12 weeks after therapy based on the HCV genotype, treatment duration and use of ribavirin (RBV) were included. The selected studies were considered for meta-analysis using STATA 11.0.

RESULTS

We found six different regimens containing DCV: DCV/asunaprevir (ASV), DCV/ASV/beclubavir, DCV/pegylated interferon lambda or alpha/RBV with or without ASV, DCV/simeprevir, DCV/VX-135 and DCV/sofosbuvir (SOF). Most of these regimens were used for the treatment of HCV genotype 1 infections, and in most cases, treatment failure was noted in subtype 1a infections. Among all these regimens, DCV/SOF with or without RBV for 12 or 24 weeks was found to be an efficacious approach for treatment of different types of patients with infections with different HCV genotypes.

CONCLUSIONS

Among the treatment regimens containing DCV, DCV/SOF has the highest SVR rate for the treatment of infection with different HCV genotypes in different patient contexts; thus, this regimen shows promise for the treatment of HCV infections.

Daclatasvir/peginterferon lambda-1a/ribavirin in patients with chronic HCV infection and haemophilia who are treatment naïve or prior relapsers to peginterferon alfa-2a/ribavirin

AIM

This study explores the potential role of a novel interferon-containing regimen for treatment of patients with chronic hepatitis C (CHC) and underlying haemophilia.

METHODS

This trial (NCT01741545) was an open-label, non-randomized phase 3 study, which included adult haemophiliacs with hepatitis C virus (HCV). Patients with HCV genotypes (GT)-2 or -3 were treated with Lambda-IFN/ribavirin (RBV)/daclatasvir (DCV) for 12 weeks (cohort A). Patients with HCV GT-1b or -4 were treated with Lambda-IFN/RBV/DCV for 12 weeks, followed by Lambda-IFN/RBV for an additional 12 weeks (cohort B). The primary endpoint was the proportion of patients with a sustained virologic response at post-treatment follow-up week 12 (SVR12). Clinical development of Lambda-IFN was discontinued during this trial leading to study termination before a 24-week post-treatment follow-up was obtained for all participants.

RESULTS

Overall, 51 patients were treated (cohort A, n = 12; cohort B, n = 39). The proportion of patients achieving SVR12 was 92% in cohort A and 90% in cohort B. Therapy was generally well tolerated. The most common adverse events (AEs) were related to elevations in serum transaminases and/or bilirubin. Five serious AEs, four discontinuations due to AEs, and no deaths were reported. The rate of grade 3-4 bilirubin elevations was 17-18% across cohorts.

CONCLUSION

Lambda-IFN/RBV/DCV treatment demonstrated a high SVR rate and was generally well tolerated with a safety profile consistent with expectations for this special patient population. This study supports use of DCV as part of a combination treatment regimen for haemophiliacs with CHC.

Discovery of a Potent Acyclic, Tripeptidic, Acyl Sulfonamide Inhibitor of Hepatitis C Virus NS3 Protease as a Back-up to Asunaprevir with the Potential for Once-Daily Dosing

The discovery of a back-up to the hepatitis C virus NS3 protease inhibitor asunaprevir (2) is described. The objective of this work was the identification of a drug with antiviral properties and toxicology parameters similar to 2, but with a preclinical pharmacokinetic (PK) profile that was predictive of once-daily dosing. Critical to this discovery process was the employment of an ex vivo cardiovascular (CV) model which served to identify compounds that, like 2, were free of the CV liabilities that resulted in the discontinuation of BMS-605339 (1) from clinical trials. Structure-activity relationships (SARs) at each of the structural subsites in 2 were explored with substantial improvement in PK through modifications at the P1 site, while potency gains were found with small, but rationally designed structural changes to P4. Additional modifications at P3 were required to optimize the CV profile, and these combined SARs led to the discovery of BMS-890068 (29).

Resistance Analyses of HCV NS3/4A Protease and NS5B Polymerase from Clinical Studies of Deleobuvir and Faldaprevir

Background & Aim

The resistance profile of anti-hepatitis C virus (HCV) agents used in combination is important to guide optimal treatment regimens. We evaluated baseline and treatment-emergent NS3/4A and NS5B amino-acid variants among HCV genotype (GT)-1a and -1b-infected patients treated with faldaprevir (HCV protease inhibitor), deleobuvir (HCV polymerase non-nucleoside inhibitor), and ribavirin in multiple clinical studies.

Methods

HCV NS3/4A and NS5B population sequencing (Sanger method) was performed on all baseline plasma samples (n = 1425 NS3; n = 1556 NS5B) and on post-baseline plasma samples from patients with virologic failure (n = 113 GT-1a; n = 221 GT-1b). Persistence and time to loss of resistance-associated variants (RAVs) was estimated using Kaplan–Meier analysis.

Results

Faldaprevir RAVs (NS3 R155 and D168) and deleobuvir RAVs (NS5B 495 and 496) were rare (<1%) at baseline. Virologic response to faldaprevir/deleobuvir/ribavirin was not compromised by common baseline NS3 polymorphisms (e.g. Q80K in 17.5% of GT-1a) or by NS5B A421V, present in 20% of GT-1a. In GT-1b, alanine at NS5B codon 499 (present in 15% of baseline sequences) was associated with reduced response. Treatment-emergent RAVs consolidated previous findings: NS3 R155 and D168 were key faldaprevir RAVs; NS5B A421 and P495 were key deleobuvir RAVs. Among on-treatment virologic breakthroughs, RAVs emerged in both NS3 and NS5B (>90%). Virologic relapse was associated with RAVs in both NS3 and NS5B (53% GT-1b; 52% GT-1b); some virologic relapses had NS3 RAVs only (47% GT-1a; 17% GT-1b). Median time to loss of GT-1b NS5B P495 RAVs post-treatment (5 months) was less than that of GT-1b NS3 D168 (8.5 months) and GT-1a R155 RAVs (11.5 months).

Conclusion

Faldaprevir and deleobuvir RAVs are more prevalent among virologic failures than at baseline. Treatment response was not compromised by common NS3 polymorphisms; however, alanine at NS5B amino acid 499 at baseline (wild-type in GT-1a, polymorphism in GT-1b) may reduce response to this deleobuvir-based regimen.

Safety of interferon-free therapies for chronic hepatitis C: a network meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Interferon-free (IFN-free) therapies for hepatitis C virus (HCV) have been developed to provide more effective, tolerable and safer therapeutic strategies. To date, no network meta-analysis (NMA) evaluating the safety profile of these regimens has been performed. This systematic review and NMA aimed to evaluate safety outcomes of IFN-free treatment options for chronic hepatitis C.

METHODS

A systematic review was performed according to PRISMA and Cochrane recommendations. A literature search was conducted in PubMed/Medline, Scopus, Cochrane Library, International Pharmaceutical Abstracts and Web of Science electronic databases and included only randomized clinical trials that provided safety outcomes of interest of evaluated second-generation direct-acting antivirals: incidence of any adverse events (AEs) and serious AE. NMA allowed estimating probability for the relative safety of the interventions. A consistency model was used to draw conclusions about relative safety of treatments, presented as odds ratio (OR) and corresponding 95% credible interval (CrI).

RESULTS

Fifty-one clinical trials were included (13 089 participants). Most participants had hepatitis C genotype 1 virus (76%) and were treated for 12 weeks. Two NMAs were built to investigate the incidence of AEs and serious AEs, comparing 13 and 10 IFN-free treatment options, respectively. For the outcome incidence of AEs, few significant differences were observed, which were explained by the presence of RBV. Elbasvir with grazoprevir and placebo were both safer than ombitasvir in combination with paritaprevir, ritonavir, daclatasvir plus RBV [ORs with 95% Crl of 4·09 (1·17-14·09) and 2·40 (1·19-4·77), respectively] and sofosbuvir with RBV [ORs with 95% Crl of 0·22 (0·07-0·72) and 2·69 (1·53-4·80), respectively]. Furthermore, elbasvir with grazoprevir was safer than sofosbuvir used with velpatasvir and RBV [OR 0·19 (95% CrI 0·03-0·98)]; ombitasvir in combination with paritaprevir, ritonavir, daclatasvir was safer than the same therapy but combined with RBV [OR 2·14 (95% CrI 1·09-4·44)]; and sofosbuvir used with velpatasvir was safer than sofosbuvir with RBV [OR 2·07 (95% CrI 1·13-3·79)]. Elbasvir with grazoprevir (50%) followed by placebo (28%) had the highest probabilities of less AEs. No significant differences were observed for serious AE outcomes.

WHAT IS NEW AND CONCLUSION

This meta-analysis included a large number of therapies. Small differences were observed in any AEs, but not in serious AEs.

Efficacy and safety of daclatasvir and asunaprevir for hepatitis C virus genotype 1b infection

BACKGROUND/AIMS

The treatment strategy for hepatitis C virus (HCV) has been changing rapidly since the introduction of direct-acting antivirals such as daclatasvir (DCV) and asunaprevir (ASV). We evaluated the efficacy and safety of DCV and ASV for HCV in real-life practice.

METHODS

Patients were treated with 60 mg of DCV once daily plus 200 mg of ASV twice daily for 24 weeks, and followed for 12 weeks. The primary endpoint was a sustained virological response at 12 weeks after treatment (SVR12) and safety.

RESULTS

This retrospective study included eight patients with chronic HCV genotype 1b infection. All of the enrolled patients were diagnosed with liver cirrhosis, and their mean age was 65.75 years. One patient was a nonresponder and two patients relapsed with previous pegylated interferon (PegIFN) and ribavirin (RBV) treatment. None of the patient showed NS5A mutation. An SVR12 was achieved in 88% of cases by the DCV and ASV combination therapy. The serum transaminase level and the aspartate-aminotransferase-to-platelet ratio were improved after the treatment. DCV and ASV were well tolerated in most of the patients, with treatment discontinuation due to adverse events (elevated liver enzyme and decompensation) occurring in two patients.

CONCLUSION

In this study, combination of DCV and ASV treatment achieved a high sustained virological response with few adverse events even in those with cirrhosis, advanced age, and nonresponse/relapse to previous interferon-based therapy. Close monitoring of safety issues may be necessary when treating chronic HCV patients receiving DCV and ASV, especially in older patient and those with cirrhosis.

History and future of antiviral therapy of chronic hepatitis C

Hepatitis C virus (HCV) infection often leads to chronic diseases, and antiviral therapy is an important way to prevent chronic hepatitis C from progressing to end-stage liver disease. Up to now, hepatitis C antiviral therapy has successively experienced eras of interferon monotherapy, interferon and ribavirin combination therapy, and combination therapy of pegylated-interferon (PEG-IFN) and ribavirin. Now we are entering into a new era of direct-acting antiviral agents (DAAs). Just like acquired immune deficiency syndrome (AIDS) cocktails, combination therapy consists of two or more antiviral agents. DAAs will be the primary antiviral therapy for hepatitis C in the future for their better tolerance, lower drug resistance, higher sustained virological response and shorter treatment course. In this article, we review the history and future of antiviral therapy of HCV infection.

Racial Disparities in Treatment Rates for Chronic Hepatitis C: Analysis of a Population-Based Cohort of 73,665 Patients in the United States

Chronic hepatitis C (CHC) disproportionately affects racial minorities in the United States (US). Although prior studies have reported lower treatment rates in Blacks than in Caucasians, the rates of other minorities remain understudied. We aimed to examine antiviral treatment rates by race and to evaluate the effect of other demographic, medical, and psychiatric factors on treatment rates. We performed a population-based study of adult CHC patients identified via ICD-9CM query from OptumInsight's Data Mart from January 2009 to December 2013. Antiviral treatment was defined by pharmaceutical claims for interferon and/or pegylated-interferon. A total of 73,665 insured patients were included: 51,282 Caucasians, 10,493 Blacks, 8679 Hispanics, and 3211 Asians. Caucasians had the highest treatment rate (10.7%) followed by Blacks (8.8%), Hispanics (8.8%), and Asians (7.9%, P < .001). Hispanics had the highest cirrhosis rates compared with Caucasians, Blacks, and Asians (20.7% vs 18.3%, 17.1%, and 14.3%, respectively). Caucasians were the most likely to have a psychiatric comorbidity (20.1%) and Blacks the most likely to have a medical comorbidity (44%). Asians were the least likely to have a psychiatric (6.4%) or medical comorbidity (26.9%). On multivariate analysis, racial minority was a significant predictor of nontreatment with odds ratios of 0.82 [confidence interval (CI): 0.74-0.90] for Blacks, 0.87 (CI: 0.78-0.96) for Hispanics, and 0.73 (CI: 0.62-0.86) for Asians versus Caucasians. Racial minorities had lower treatment rates than Caucasians. Despite fewer medical and psychiatric comorbidities and higher incomes and educational levels, Asians had the lowest treatment rates. Hispanics also had lower treatment rates than Caucasians despite having higher rates of cirrhosis. Future studies should aim to identify underlying racial-related barriers to hepatitis C virus treatment besides socioeconomic status and medical or psychiatric comorbidities.

Resistance to direct-acting antiviral agents: clinical utility and significance

PURPOSE OF REVIEW

This article examines the dynamics and factors underlying hepatitis C virus (HCV) resistance, along with their impact on daily clinical management of HCV-infected patients.

RECENT FINDINGS

Across available treatment-regimens, GT-3 is the most difficult-to-cure genotype, but also genotype-1a may show lower success-rates compared with genotype-1b. Natural resistance to NS3, NS5A and NS5B inhibitors may contribute to treatment failures. The Q80K NS3-protease mutation affects sensibility to simeprevir + peg-interferon/ribavirin combinations. It reaches up to 48% prevalence in genotype-1a in some studies (but it is lower in other). Resistant variants (particularly in NS5A) developed at failure can persist, in a substantial proportion of patients, even 3 years after treatment-discontinuation, potentially affecting readministration of the same direct-acting antiviral agent (DAA)-class. This will become an issue for those patients failing all-oral regimens with multiple-resistant viruses.

SUMMARY

Recent data support the importance of an accurate genotype and genotype-1 subtype (1a/1b) assignment prior therapy. Resistance testing at baseline has no clear indication so far in clinical practice for all-DAA regimens selection, while it remains a valuable option at the retreatment of patients who failed DAA-containing regimens, provided that data are generated to inform treatment decisions based on the results of resistance testing. In this context, long-term RAVs persistence after failure should be taken into account.