GS‐9857 in patients with chronic hepatitis C virus genotype 1–4 infection: a randomized,double‐blind,dose‐ranging phase 1 study

GS‐9857, an inhibitor of the hepatitis C virus (HCV) nonstructural protein (NS) 3/4A, demonstrates potent activity against HCV genotypes 1–6 and improved coverage against commonly encountered NS3 resistance‐associated variants (RAVs). In this study, the safety, tolerability, antiviral activity and pharmacokinetics (PK) of GS‐9857 were evaluated in patients with chronic HCV genotype 1–4 infection. Patients with genotype 1–4 infection received placebo or once‐daily GS‐9857 at doses ranging from 50 to 300 mg for 3 days under fasting conditions. GS‐9857 was well tolerated; all reported adverse events (AEs) were mild or moderate in severity. Diarrhoea and headache were the most commonly reported AEs. Grade 3 or 4 laboratory abnormalities were observed in 17% of patients receiving GS‐9857; there were no Grade 3 or 4 abnormalities in alanine aminotransferase, aspartate aminotransferase or alkaline phosphatase levels. GS‐9857 demonstrated potent antiviral activity in patients with chronic HCV infection, achieving mean and median maximum reductions in HCV RNA of ≥3 log₁₀ IU/mL following administration of a 100‐mg dose in patients with HCV genotype 1a, 1b, 2, 3 or 4 infection. The antiviral activity of GS‐9857 was unaffected by the presence of pretreatment NS3 RAVs. In patients with genotype 1–4 infection, GS‐9857 exhibited linear PK and was associated with a median half‐life of 29–42 h, supporting once‐daily dosing. Thus, the tolerability, efficacy and pharmacokinetic profile of GS‐9857 support its further evaluation for treatment of patients with chronic HCV infection.     

A randomized,placebo‐controlled study of the NS5B inhibitor beclabuvir with peginterferon/ribavirin for HCV genotype 1

Beclabuvir is a potent, non‐nucleoside inhibitor of the HCV NS5B RNA polymerase, with nanomolar activity against HCV genotypes 1, 3, 4, 5 and 6 in vitro. This study evaluated the efficacy and safety of beclabuvir, in combination with peginterferon alfa‐2a (pegIFN) and ribavirin (RBV), in HCV genotype 1. In this randomized (1:1:1), double‐blinded, placebo‐controlled, dose‐ranging phase 2a study, 39 treatment‐naive patients chronically infected with HCV genotype 1 were treated for 48 weeks with beclabuvir (75 mg or 150 mg) plus pegIFN (180 μg) and RBV (1000 mg/day [<75 kg] or 1200 mg/day [≥75 kg]) vs pegIFN/RBV alone. The primary efficacy endpoint of extended rapid virologic response (undetectable HCV RNA at treatment weeks 4 and 12) was achieved by 76.9% (10/13) of patients receiving beclabuvir 75 mg and 38.5% (5/13) receiving beclabuvir 150 mg vs 0% receiving pegIFN/RBV alone. Higher response rates were observed among patients receiving beclabuvir 75 mg for all secondary efficacy endpoints, including sustained virologic response at follow‐up weeks 12 or 24. Three patients experienced virologic breakthrough on treatment, all in the beclabuvir 150‐mg treatment group. Beclabuvir was well tolerated at both doses, with the most commonly observed adverse events (headache, fatigue, nausea, decreased appetite, irritability, depression and insomnia) consistent with those observed with pegIFN/RBV. In conclusion, beclabuvir was both effective and well tolerated when administered in combination with pegIFN/RBV for the treatment of chronic HCV GT 1, supporting the study of beclabuvir as part of an all‐oral regimen for HCV GT1.     

All‐oral therapy with nucleotide inhibitors sofosbuvir and GS‐0938 for 14 days in treatment‐naive genotype 1 hepatitis C (NUCLEAR)

Sofosbuvir and GS‐0938 are distinct nucleotide analogues with activity against hepatitis C virus (HCV) in vitro. We evaluated the antiviral activity and safety of sofosbuvir and GS‐0938 alone and in combination in HCV genotype 1 patients. In this double‐blind study, 40 treatment‐naïve patients were randomly assigned to 4 treatment cohorts: (i) GS‐0938 for 14 days, (ii) GS‐0938 for 7 days followed by GS‐0938 plus sofosbuvir for 7 days, (iii) sofosbuvir for 7 days followed by GS‐0938 plus sofosbuvir for 7 days and (iv) GS‐0938 plus sofosbuvir for 14 days. In each arm, 8 patients received active drug and 2 placebo. After 7 days of dosing, patients in all 4 dose groups experienced substantial reductions in HCV RNA, with median declines (Q1, Q3) of ?4.50 (?4.66, ?4.24) in Cohort 1, ?4.55 (?4.97, ?4.13) in Cohort 2, ?4.65 (?4.78, ?4.17) in Cohort 3 and ?4.43 (?4.81, ?4.13) in Cohort 4; patients receiving placebo had essentially no change in HCV RNA (+0.07 log₁₀ IU/mL). Seven days after the end of treatment, the proportions of patients with HCV RNA <15 IU/mL were 4 (50%), 8 (100%), 7 (88%) and 5 (63%) for Cohorts 1–4, respectively, vs 0 for placebo. No viral breakthrough or resistance mutations were observed. No serious adverse events or Grade 3 or 4 adverse events were reported. Sofosbuvir and GS‐0938—alone and in combination—were well tolerated and led to substantial reductions in viral load. Sofosbuvir is undergoing further investigation as a possible backbone of an all‐oral regimen for chronic HCV.     

The presence of resistance mutations to protease and polymerase inhibitors in Hepatitis C virus sequences from the Los Alamos databank

Several new direct‐acting antiviral (DAA) drugs are in development for chronic hepatitis C viral (HCV) infection, and NS3‐NS4A serine protease and the NS5B RNA‐dependent RNA polymerase have been the major targets. HCV variants displaying drug‐resistant phenotypes have been observed both in vitro and during clinical trials. Our aim was to characterize amino acid changes at positions previously associated with resistance in protease (NS3) and polymerase (NS5B) regions from treatment‐naïve HCV patients infected with genotypes 1a, 1b and 3a. All 1383 NS3 protease sequences (genotype 1a = 680, 1b = 498 and 3a = 205) and 806 NS5B polymerase sequences (genotypes 1a = 471, 1b = 329, 3a = 6) were collected from Los Alamos databank. Genotype 3a protease sequences showed the typical low‐level resistance mutation V36L. NS3 sequences from other genotypes presented mutations on positions 36, 39, 41, 43, 54, 80, 109, 155 and 168 in a frequency lower than 2%, except for the mutation Q80R found in 35% of genotype 1a isolates. Polymerase sequences from genotype 3a patients showed five typical mutations: L419I, I424V, I482L, V499A and S556G. Two positions presented high polymorphism in the NS5B region from genotype 1a (V499A) and genotype 1b (C316N) subjects. Our results demonstrated a natural profile of genotype 3a that can be associated with the pre‐existence of HCV variants resistant to first‐generation protease inhibitors and to non‐nucleoside polymerase inhibitors. Likewise, genotype 1b isolates and genotype 1a sequences exhibited pre‐existing mutations associated with resistance to Palm II and Thumb I polymerase inhibitors, respectively.     

Nonstructural protein 5A resistance profile in patients with chronic hepatitis C treated with ledipasvir‐containing regimens without sofosbuvir

The study aimed to evaluate the effects of baseline hepatitis C virus (HCV) nonstructural protein 5A (NS5A) resistance‐associated substitutions (RASs) on sustained virologic response to ledipasvir (LDV)‐containing regimens in the absence of sofosbuvir (SOF) in patients with HCV genotype (GT) 1 infection across 6 phase 2 clinical studies. We analysed data from 1103 patients who received either LDV + vedroprevir (NS3 protease inhibitor) + tegobuvir (NS5B inhibitor) ± ribavirin or LDV + ribavirin + pegylated interferon. Population sequencing of HCV NS5A was performed at baseline and at virologic failure from patient plasma samples. Of 1045 patients with available baseline sequences, 747 (67.7%) had GT1a, and 298 (26.9%) had GT1b infection. The overall prevalence of NS5A RASs at baseline was 9.4%; 7.6% (57/747) and 13.8% (41/298) of patients with GT1a and GT1b infection, respectively. The majority of GT1a‐infected patients with NS5A RASs at baseline had a single NS5A RAS (78.9%) at NS5A positions K24R, M28T, Q30H/L, L31M and Y93H/N/C/S. The spectrum of NS5A RASs detected in GT1b patients was much less diverse compared to GT1a patients, with all patients harbouring a single NS5A RAS either L31M or Y93H/C. For patients treated with LDV‐containing regimens in the absence of SOF, the presence of baseline NS5A RASs was associated with low SVR rates. In patients with virologic failure, nearly all had either pre‐existing and/or emergent NS5A RASs: 287/287 (100%) and 40/42 (95.2%) patients with GT1a and GT1b infection, respectively. Three novel NS5A substitutions were identified as emergent NS5A RASs: K26E and S38F in GT1a; and L31I in GT1b. In conclusion, the presence of NS5A RASs at baseline reduced the SVR rate in patients treated with LDV in combination vedroprevir + tegobuvir ± ribavirin or ribavirin + pegylated interferon. Virologic failure was associated with the detection of NS5A RASs in nearly all patients. These results suggest that the resistance barrier may differ depending on HCV drug combination and may be more important than that of the individual DAAs.     

Evaluation of 8‐week glecaprevir/pibrentasvir treatment in direct‐acting antiviral‐naïve noncirrhotic HCV genotype 1 and 2infected patients in a real‐world setting in Japan

Based on high efficacy and safety demonstrated in clinical trials, treatment with glecaprevir/pibrentasvir (G/P) for 8 weeks is recommended for hepatitis C virus (HCV)–infected patients who are direct‐acting antiviral (DAA) naïve, genotype 1 or 2, and noncirrhotic. The aim of this study was to validate real‐world experience with 8‐week G/P treatment in Japan. We conducted a prospective observational cohort study in 554 patients who underwent 8‐week treatment from among 1,022 patients who initiated G/P therapy. The majority (54.5%) were male, with a median age of 66 years, and HCV genotype distribution was genotype 1, 43.8%; genotype 2, 55.3%; and mixed subtype, 0.9%. Overall, the sustained virologic response rate at 12 weeks (SVR12) was 92.8% (530/571) in the intention‐to‐treat population and 99.3% (526/530) in the per‐protocol population. The SVR12 rates by subgroups were as follows: subtype 1a, 100% (6/6); 1b, 100% (189/189); 2a, 99.3% (150/151); 2b, 99.0% (103/104); and mixed subtype, 50% (2/4). Among four patients with virologic failure following 8‐week treatment with G/P, none had baseline polymorphisms or treatment‐emergent amino acid substitutions in NS3. However, 2 of 4 patients with virologic failure had treatment‐emergent amino acid substitutions in NS5A. Adverse events (AEs) were reported in 21.5% of patients and 1.2% of patients discontinued due to drug‐related AEs. In conclusion, G/P treatment for 8 weeks was safe and effective for DAA‐naïve noncirrhotic genotype 1 or 2 patients in a real‐world clinical setting in Japan.     

Retreatment of patients with chronic hepatitis C,subtype 1b and cirrhosis,who failed previous direct‐acting antiviral therapy including first‐ and second‐generation NS5A inhibitors with ombitasvir/paritaprevir/ritonavir,dasabuvir + sofosbuvir + ribavirin

The use of direct‐acting antiviral agents (DAAs) in patients with chronic HCV genotype 1 infection results in sustained virologic response (SVR) rates of 95%‐97%, but 3%‐5% of patients experience virologic failure. We observed 17 patients infected with HCV subtype 1b who failed previous treatment with DAA, including 13 subjects (76.5%) with liver cirrhosis. Twelve subjects (70.6%) previously received NS5A inhibitors of the first generation (ledipasvir or daclatasvir) and five subjects (29.4%) – the second generation (velpatasvir). All patients were retreated with a combination of ombitasvir/paritaprevir/ritonavir and dasabuvir (3D) with sofosbuvir (SOF) and ribavirin (RBV). We compared SVR₁₂ rates depending on fibrosis stage, presence of just single or double NS5A mutations (L31M/V/I and/or Y93H), and on the generation of previously used NS5A inhibitor. Observed SVR₁₂ rates were as follows: 94.1% (16/17 patients) overall; 100% in patients without cirrhosis (n = 4) vs 92.3% in those with cirrhosis (n = 13); 100% with single L31M/V/I or Y93H mutation (n = 7) vs 88.9% with double mutations (n = 9); 100% in patients who previously failed first generation (n = 12) vs 80.0% in those failed second‐generation NS5A inhibitors (n = 5). Retreatment with 3D + 0SOF + RBV was highly effective and safe in patients with chronic HCV GT1b infection who failed previous use of NS5A inhibitors. Fibrosis stage, baseline presence of NS5A RAS mutations and the generation of previously used NS5A inhibitors may impact the probability of achieving SVR₁₂, but statistical significance was not demonstrated in our small retrospective cohort. Further studies in a larger population are needed to confirm or not the predictive value of these baseline factors.     

A case of genotype‐3b hepatitis C virus in which the whole genome was successfully analyzed using third‐generation nanopore sequencing

A 42‐year‐old Chinese man with chronic hepatitis C virus (HCV) infection visited our hospital for antiviral therapy. The subgenotype could not be determined using the HCV GENOTYPE Primer Kit (Institute of Immunology, Tokyo, Japan), which can identify genotype 3a HCV exclusively among genotype 3 HCV. Thus, the whole‐genome sequence of HCV was analyzed using the MinION nanopore sequencer (Oxford Nanopore Technologies, Oxford, UK), a third‐generation single‐molecule sequencing platform. Consequently, a total of 9442 bases with a 73.6 mean depth, corresponding to the sequences between nt25 and PolyU/UC were determined (LC414155.2). The similarity analysis revealed that the obtained sequence was classified into genotype 3b HCV and showed nucleotide identities from 87.6% to 93.9% with those of 12 previously reported strains. Furthermore, possible resistance‐associated substitutions in non‐structural protein (NS)3, NS5A, and NS5B based on consensus sequences of 12 genotype 3b HCV strains, including NS5A‐Y93H and NS5B‐S282 T substitutions, were absent. In conclusion, the MinION nanopore sequencer is useful for analyzing the HCV genome, especially the genomes of genotype 3 HCV strains for which standardized real‐ time PCR methods for all subgenotypes have not been established.     

Time to viral suppression is not related to achievement of SVR12 in HCV GT1‐infected patients treated with ombitasvir/paritaprevir/ritonavir and dasabuvir with or without ribavirin

High rates of sustained virologic response at post‐treatment week 12 (SVR12) were achieved in six phase 3 trials of ombitasvir (OBV, an NS5A inhibitor), paritaprevir (an NS3/4A protease inhibitor) co‐dosed with ritonavir (PTV/r) + dasabuvir (DSV, an NS5B RNA polymerase inhibitor) (ie, 3D regimen) with or without ribavirin (RBV) in adults with chronic genotype (GT) 1 hepatitis C virus (HCV) infection. We assessed whether time to first HCV RNA value below the lower limit of quantification in patients with and without cirrhosis was associated with achievement of SVR12. Data were analysed from GT1‐infected patients enrolled in six phase 3 studies of 3D ± RBV. Patients who experienced non‐virologic failure were excluded from analysis. HCV RNA was determined using the Roche COBAS TaqMan RT‐PCR assay (lower limit of quantification, LLOQ =25 IU/mL). SVR12 was analysed by week of first HCV RNA suppression, defined as HCV RNA <LLOQ. The analysis included a total of 2027 patients. Cumulative proportions of subjects with initial HCV RNA suppression <LLOQ at weeks 1, 2, 4 and 6 were 31%, 81%, 99% and 100%, respectively. SVR12 was achieved by 98%, 97%, 98% and 92% of patients with initial suppression at Weeks 1, 2, 4 and 6, respectively (P=.42, trend test). Across six phase 3 trials of 3D ± RBV, most patients achieved viral suppression by week 2. Time to viral suppression was not associated with subsequent achievement of SVR12, suggesting that on‐treatment virologic monitoring may not be necessary with this regimen.     

Efficacy and safety of 12 weeks of elbasvir ± grazoprevir ± ribavirin in participants with hepatitis C virus genotype 2, 4, 5 or 6 infection: The C‐SCAPE study

People with hepatitis C virus (HCV) infection other than genotype 1 represent a heterogeneous group. The aim of the phase 2 C‐SCAPE study was to evaluate elbasvir/grazoprevir (EBR/GZR), with or without ribavirin (RBV), in participants with HCV genotype 2, 4, 5 or 6 infection. This was a part randomised, open‐label, parallel‐group study (NCT01932762; PN047‐03) of treatment‐naive, noncirrhotic participants. Participants with HCV genotype 2 infection received GZR 100 mg + RBV ± EBR 50 mg for 12 weeks and those with genotype 4, 5 or 6 infection were randomized to receive EBR/GZR ± RBV for 12 weeks. The primary endpoint was sustained virological response 12 weeks after completion of treatment (SVR12; HCV RNA <25 IU/mL). Among participants with genotype 2 infection, SVR12 was achieved by 80% (24/30) of those receiving EBR/GZR + RBV and 73% (19/26) of those receiving GZR + RBV. SVR rates were high in participants with HCV genotype 4 infection receiving EBR/GZR with and without RBV (100% [10/10] and 90% [9/10]; respectively). In contrast, the addition of RBV to EBR/GZR appeared to increase SVR12 in participants with genotype 5 infection (EBR/GZR, 25%; EBR/GZR + RBV 100% [4/4]). In participants with genotype 6 infection, SVR12 was 75% (3/4) in both those receiving EBR/GZR and those receiving EBR/GZR + RBV. The safety profile was similar across treatment arms, with adverse events tending to occur more frequently among participants receiving RBV. In conclusion, these data support the inclusion of participants with genotype 4 or 6 infection in the EBR/GZR phase 3 studies. EBR/GZR ± RBV was unsatisfactory for participants with genotype 2 or 5 infection.     

No one size fits all—Shortening duration of therapy with direct‐acting antivirals for hepatitis C genotype 1 infection

The advent of shorter duration, highly effective and well‐tolerated interferon‐free therapy now provides an opportunity for virtually all HCV‐infected individuals to be cured. However, there continues to be a need to simplify and shorten treatment duration. Shortening therapy to 8 weeks with sofosbuvir and ledipasvir can be considered in treatment patients with HCV genotype 1 infection and low baseline viral load. A number of other 8‐week dual and triple therapy direct‐acting antiviral (DAA) regimens are in advanced clinical development. Several small studies have further demonstrated the feasibility of 6 weeks of sofosbuvir therapy in combination with an NS5A inhibitor and a protease inhibitor for HCV genotype 1. Four weeks of therapy with various combinations of the currently available DAAs appears to be suboptimal with poor response rates observed in phase 2 trials. Response‐guided therapy is another promising tool that may allow for shorter therapy but require further research. Shortening therapy and retreating relapsers may be a viable cost‐saving measure, but requires further cost‐benefit analysis and more data on the impact of resistance on retreatment options.     

GSK2878175, a pan‐genotypic non‐nucleoside NS5B polymerase inhibitor,in healthy and treatment‐naïve chronic hepatitis C subjects

GSK2878175 is a potent, pan‐genotypic, non‐nucleoside, nonstructural protein 5B palm polymerase inhibitor being developed for the treatment of chronic hepatitis C (CHC). A first‐in‐human, randomized, placebo‐controlled, dose escalation study, evaluated the safety and pharmacokinetics of GSK2878175 administered as single and repeat oral doses (once daily for 14 days) to healthy volunteers. A separate proof‐of‐concept, placebo‐controlled, repeat dose (once daily for 2 days) study evaluated the safety, pharmacokinetics and antiviral activity of GSK2878175 monotherapy in treatment‐naïve, noncirrhotic, subjects with hepatitis C virus (HCV) genotype 1 [1a and 1b], 2, or 3. No deaths or SAEs were reported in either study, and treatment was well‐tolerated. Across all the HCV genotypes, GSK2878175 monotherapy at doses of 10, 30 or 60 mg once daily for 2 days produced a statistically significant multilog reduction (P<.001) in plasma HCV RNA log₁₀ IU/mL from Baseline to 24, 48 and 72 hours after the first dose of GSK2878175 compared to placebo. The reduction in HCV RNA was sustained for a prolonged period across all of the active treatment groups, consistent with the long apparent half‐life of GSK2878175 that was observed (mean t_1/2 range: 60‐63 hours in the CHC subjects). In summary, GSK2878175, when administered to healthy subjects and subjects with CHC, did not reveal any safety concerns that would limit or preclude further clinical development. GSK2878175 monotherapy across a wide dose range produced substantial reduction in HCV RNA, irrespective of HCV genotype. The results from these studies support further evaluation of GSK2878175‐based regimens.     

Safety and efficacy of coblopasvir and sofosbuvir in patients with genotypes 1, 2, 3 and 6 HCV infections without or with compensated cirrhosis

A simple, pangenotypic and effective treatment regimen for patients with a broad range of chronic hepatitis C virus (HCV) infections remains an unmet medical need. We conducted a phase 2, randomized, open study involving untreated patients with chronic HCV genotypes 1, 2, 3, or 6 infections. Patients without cirrhosis were randomly assigned in a 1:2 ratio to receive capsules of the NS5A inhibitor coblopasvir at a dose of 30 or 60 mg plus tablets of the nucleotide polymerase inhibitor sofosbuvir (400 mg) once daily for 12 weeks. Patients with cirrhosis received 60 mg coblopasvir plus sofosbuvir for 12 weeks. The primary endpoint was the sustained virologic response at 12 weeks after the end of therapy (SVR12). Of the 110 patients who were enrolled in the study, 59 were male, 62.7% had HCV genotype 1, 24.5% had genotype 2, 6.4% had genotype 3, and 6.4% had genotype 6. The average age was 45.5 years. A total of 10.9% of patients had compensated cirrhosis. The rate of SVR12 was 98.2% in the intention‐to‐treat (ITT). One genotype 6 patient with cirrhosis experienced virologic relapse. One genotype 2 patient without cirrhosis failed to complete the follow‐up and quit the study. Serious adverse events (SAEs) were reported in 2 patients and were not related to coblopasvir and sofosbuvir. Most adverse events (AEs) did not require treatment. Coblopasvir plus sofosbuvir taken once daily for 12 weeks provided high rates of sustained virologic response (SVR) and had a good safety profile among patients with HCV genotypes 1, 2, 3, or 6 infections, including those with compensated cirrhosis.     

Sustained virological response with 16‐week glecaprevir/pibrentasvir after failure to sofosbuvir/velpatasvir in post‐transplant severe HCV recurrence in HIV

Direct‐acting antivirals (DAAs) demonstrated high efficacy and safety even in the post‐liver transplant (LT) setting and in HIV‐infected patients, but data are very limited in the early post‐LT period with the most recently available DAA. Two HIV/HCV‐coinfected LT recipients (both grafts from HIV/HCV‐negative donors) experienced early HCV recurrence with severe hepatitis and were treated with sofosbuvir/velpatasvir for 12 weeks. Unfortunately, both patients failed: one (genotype 4d) showed virological breakthrough at week 3 with resistance‐associated substitutions (RASs) for both NS5A and NS5B, while the other (genotype 1a) experienced virological relapse without RAS. Both progressed to fibrosing cholestatic hepatitis and were successfully retreated with glecaprevir/pibrentasvir for 16 weeks achieving sustained virological response. The higher prevalence of RAS in experienced genotype 4 patients and the long time to viral suppression observed in subjects with fibrosing cholestatic hepatitis should be taken into account, considering longer treatment duration to increase the chances of achieving sustained virological response.     

Differential virus‐specific CD8+ T‐cell epitope repertoire in hepatitis C virus genotype 1 versus 4

Virus‐specific CD8⁺ T‐cell responses play an important role in the outcome of hepatitis C virus (HCV) infection. To date, most HCV‐specific CD8⁺ T‐cell epitopes have been defined in HCV genotype 1 infection. In contrast, the HCV genotype 4‐specific CD8⁺ T‐cell response is poorly defined. Here, we analysed whether known HCV‐specific CD8⁺ T‐cell epitopes are also recognized in HCV genotype 4‐infected patients and set out to identify the first HCV genotype 4‐specific CD8⁺ T‐cell epitopes. We studied patients chronically infected with HCV genotype 1 (n = 20) or 4 (n = 21) using 91 well‐described HCV‐specific epitope peptides. In addition, we analysed 24 genotype 4‐infected patients using 40 epitope candidates predicted using an in silico approach. HCV‐specific CD8⁺ T‐cell responses targeting previously described epitopes were detectable in the majority of genotype 1‐infected patients (11 of 20). In contrast, patients infected with HCV genotype 4 rarely targeted these epitopes (4 of 21; P = .0247). Importantly, we were able to identify eight novel HCV genotype 4‐specific CD8⁺ T‐cell epitopes. Only one of these epitopes was shared between genotype 1 and genotype 4. These results indicate that there is little overlap between CD8⁺ T‐cell repertoires targeting HCV genotype 1 and 4. Prophylactic vaccination studies based on HCV genotype 1 are currently underway. However, in countries with the highest prevalence of HCV infection, such as Egypt, most patients are infected with HCV genotype 4. Thus, prophylactic vaccination strategies need to be adapted to HCV genotype 4 before their application to regions where HCV genotype 4 is endemic.     

Daclatasvir/asunaprevir/beclabuvir fixed-dose combination in Japanese patients with HCV genotype 1 infection

Background

DCV-TRIO, a fixed-dose combination of daclatasvir (pangenotypic NS5A inhibitor), asunaprevir (NS3/4A protease inhibitor), and beclabuvir (non-nucleoside NS5B inhibitor), has achieved high rates of sustained virologic response at post-treatment Week 12 (SVR12) in phase 3 studies.

Methods

In this phase 3 study, DCV-TRIO for 12 weeks and daclatasvir plus asunaprevir (DUAL) for 24 weeks were studied in Japanese patients infected with HCV genotype 1 (99 % genotype 1b).

Results

SVR12 rates ≥95 % were achieved in both treatment-naive (N = 152) and interferon-experienced (N = 65) cohorts treated with DCV-TRIO for 12 weeks and were comparable across patient subgroups, including patients aged ≥65 years and those with cirrhosis. DUAL recipients (N = 75) had an SVR12 rate of 87 %. In the absence of baseline resistance-associated polymorphisms at positions NS5A-Y93H or -L31, SVR12 rates were 98 % with DCV-TRIO or DUAL. Among genotype 1b-infected patients with baseline Y93H or L31 polymorphisms, 35/38 (92 %) DCV-TRIO recipients, and 7/16 (44 %) DUAL recipients achieved SVR12. Adverse events, mostly liver related, led to treatment discontinuation in 10 % of DCV-TRIO recipients. In this group, SVR12 was achieved by 3/9 patients who discontinued before Week 4 and by 12/12 patients who completed ≥4 weeks of DCV-TRIO. Treatment-related serious adverse events occurred in 4 and 3 % of DCV-TRIO and DUAL recipients, respectively. Seven patients (9 %) discontinued DUAL due to adverse events. No deaths occurred.

Conclusion

SVR12 was achieved by 96 % of Japanese patients with HCV genotype 1 infection after 12 weeks of treatment with the DCV-TRIO regimen. DCV-TRIO and DUAL exhibited comparable safety profiles.

     

Hepatitis C treatment from “response‐guided” to “resource‐guided” therapy in the transition era from interferon‐containing to interferon‐free regimens

Peginterferon/ribavirin has been the standard‐of‐care for chronic hepatitis C virus (HCV) infections: 48 weeks for genotype 1 or 4 (HCV‐1/4) and 24 weeks for HCV‐2/3. Response‐guided therapy recommended shorter 24‐ and 16‐week regimens for HCV‐1 with lower baseline viral loads (< 400 000–800 000 IU/mL) and rapid virological response (RVR, undetectable HCV RNA at week 4) and HCV‐2/3 with RVR, respectively; and extending to 72 and 48 weeks for HCV‐1 slower responders and HCV‐2 non‐RVR patients, respectively, to improve the efficacy. The progress of directly acting antivirals (DAA), moving from interferon‐containing regimens in 2011 to interferon‐free regimens in 2013, has greatly improved the treatment success. Interferon‐containing regimens include boceprevir or telaprevir or simeprevir or daclatasvir plus peginterferon/ribavirin, 24–48 weeks, for HCV‐1 or 4. However, adding these DAA has no benefit for HCV‐1 with lower baseline viral loads/RVR. Instead, 12‐week sofosbuvir plus peginterferon/ribavirin attained sustained virological response rates of > 90% for HCV‐1/3–6. Interferon‐free regimens include two main categories: NS5B nucleotide inhibitor (sofosbuvir)‐based regimens and NS3/4A inhibitor/NS5A inhibitor‐based regimens (daclatasvir/asunaprevir, paritaprevir/r/ombitasvir/dasabuvir and grazoprevir/elbasvir). About 8–24 weeks interferon‐free regimens could achieve sustained virological response rates of 82–99% for corresponding HCV genotypes. Although the newly DAA interferon‐free regimens have high efficacy and safety, the huge budget impact increases the treatment barriers. The current recommendation should, therefore, base on the availability, indication, and cost‐effectiveness in the transition era of DAA. Based on the concept of “resource‐guided therapy,” peginterferon/ribavirin might be applied for easy‐to‐treat interferon‐eligible patients in resource‐constrained areas. Prioritizing patients for interferon‐free regimens according to “time‐degenerative factors” (age and fibrosis) is justified before the regimens becoming available and affordable.     

IL28B genetic variation and hepatitis C virus–specific CD4+ T‐cell responses in anti‐HCV‐positive blood donors

Summary. Epidemiological, viral and host factors are associated with the outcome of hepatitis C virus (HCV) infection, and strong host immune responses against HCV favour viral clearance. Recently, genome‐wide association studies have shown a strong correlation between single‐nucleotide polymorphisms (SNPs) near the interleukin‐28B (IL28B) gene and spontaneous or treatment‐induced HCV clearance. We have investigated whether protective IL28B genetic variants are associated with HCV‐specific T‐cell responses among Spanish blood donors. The rs12979860 IL28B haplotype was determined in 69 anti‐HCV‐positive blood donors (21 HCV RNA negative and 48 HCV RNA positive) and 30 seronegative donors. In all cases, HCV‐specific CD4⁺ T‐cell responses to HCV recombinant proteins (core, NS3 and NS3 helicase) were assessed by ex vivo interferon‐γ ELISpot assay. The rs12979860‐CC genotype was highly overrepresented in donors with spontaneous HCV clearance when compared to those with chronic infection (76.2%vs 29.2%, P < 0.001; odds ratio, 7.77; 95% confidence interval, 2.4–25.3, P < 0.001). HCV‐specific CD4⁺ T‐cell responses were detected in 16 (76.2%) spontaneous resolvers especially towards nonstructural proteins, but with no correlation with IL28B genotype. Chronic individuals had a significantly lower overall T‐cell response again irrespective of IL28B genotype. When spontaneous resolvers and chronic individuals were stratified according to their IL28B genotype, significantly stronger T‐cell responses were only observed among those with non‐CC haplotypes. Although the protective rs12979860 IL28B CC genotype is associated with spontaneous HCV clearance, stronger CD4⁺ T‐cell responses towards NS3 were only evident among those with non‐CC haplotypes.     

Mutations in the NS5A and E2‐PePHD regions of hepatitis C virus genotype 1b and response to combination therapy of interferon plus ribavirin

Background/aims: Combination therapy with interferon (IFN) and ribavirin is the current standard treatment for chronic hepatitis C, but the efficacy is still not satisfactory, especially for genotype 1b. NS5A and E2 proteins of hepatitis C virus (HCV) may repress the IFN‐induced RNA‐dependent protein kinase (PKR), and thus have the potential to influence the response of HCV to IFN therapy; however, this issue remains controversial. Methods: Nucleotide sequences of the PKR‐eIF2α phosphorylation homology domain (E2‐PePHD) and PKR‐binding domain (NS5A‐PKR bd) of the HCV genome were analyzed by amplification and direct sequencing in 30 HCV genotype 1b patients who had been treated with IFN and ribavirin. Results: Nine (30%) patients achieved a sustained virological response (SVR) to combination therapy. Pretreatment variables and amino acid substitutions were compared between responders and non‐responders. The responders were younger than non‐responders (37.2±10.4 vs. 45.4±9.5 years, P=0.017), whereas no significant statistical differences were found in the number of amino acid substitutions in NS5A and E2‐PePHD regions between the two groups. Conclusions: Genetic heterogeneity in NS5A and E2‐PePHD regions of the HCV genome may not serve as a predictor for treatment outcome with combination therapy in Taiwanese patients with chronic HCV genotype 1b infection.     

Hepatitis C virus NS3/4A quasispecies diversity in acute hepatitis C infection in HIV‐1 co‐infected patients

The growing number of cases of acute hepatitis C (AHC) infections among human immunodeficiency virus type 1 (HIV‐1)‐positive men who have sex with men (MSM) in the last 10 years has promoted the search for predictors of AHC clearance as well as for epidemiological networks of viral transmission. We characterized the diversity and catalytic efficiency of HCV NS3/4A protease quasispecies in AHC patients coinfected with HIV‐1. Plasma samples obtained at HCV diagnosis from 18 MSM HIV‐coinfected patients with AHC were studied. Five HCV monoinfected patient samples with AHC were also investigated. An average of 39 clones from each sample was analysed. The catalytic efficiency of the dominant quasispecies (i.e. the most abundant) from each quasispecies was also assayed for mitochondrial antiviral signalling protein (MAVS) cleavage. Phylogenetic analysis identified two clusters of patients with highly related viruses, suggesting a common source of HCV infection. None of the 18 MSM HIV‐coinfected patients spontaneously cleared HCV, although 78% of the treated patients achieved a sustained virological response after early treatment with pegylated interferon (pegIFN) plus ribavirin (RBV). The synonymous‐nonsynonymous (ds/dn) mutation ratio, a marker of selective pressure, was higher in AHC compared to 26 HIV‐1‐infected men with genotype 1a chronic hepatitis C (CHC) (P < 0.0001). NS3/4A proteases from AHC patients also exhibited higher catalytic efficiency compared to CHC patients (P < 0.0001). No differences were found when ds/dn mutation ratios and NS3/4A protease catalytic efficiencies from AHC HIV‐coinfected patients were compared with AHC monoinfected patients. The presence of epidemiological networks of HCV transmission was confirmed among HIV‐1‐positive MSM. In addition, substantial genetic diversity was demonstrated in AHC. NS3/4A protease efficiency cleaving MAVS may be associated with virus transmission and response to pegIFN/RBV treatment.