Nonstructural Protein 5A Resistance-associated Substitutions Research Articles

Utilization and effectiveness of elbasvir/grazoprevir and adoption of resistance-associated substitutions testing in real-world treatment of hepatitis C virus genotype 1A infection: results from the German Hepatitis C-Registry.

BackgroundFor treatment of genotype 1a (GT1a) infection with elbasvir/grazoprevir, the German guidelines recommend a differentiated approach depending on baseline viral load (BVL). For low BVL ≤800 000 IU/mL, treatment with 12 weeks elbasvir/grazoprevir should be considered, whereas for high BVL >800 000 IU/mL, this regimen is only recommended in nonstructural protein 5A (NS5A) resistance-associated substitutions (RAS) absence. With present NS5A RAS or when RAS-testing is not available, 16 weeks elbasvir/grazoprevir + ribavirin is preferred. Here, we investigated the adherence to these recommendations and the effectiveness of elbasvir/grazoprevir in a large German Hepatitis C-Registry GT1a cohort.MethodsFrom September 2016 until July 2018, 195 GT1a-infected patients were treated with elbasvir/grazoprevir ± ribavirin for 12–16 weeks. The primary outcome was per protocol SVR12 or SVR24.ResultsMean age was 50 years, 89% were male, 19% had cirrhosis, 72% were treatment-naïve. Forty-five percent had low BVL ≤800 000 IU/mL, 55% high BVL >800 000 IU/mL, of whom 49 vs. 42% were baseline RAS-tested. Four patients with high (7.7%) and two with low BVL (5%) had NS5A RAS of whom 50% received elbasvir/grazoprevir+ribavirin, respectively. Ninety-four percent of patients with low and 65% with high BVL received elbasvir/grazoprevir without ribavirin. Thirty-five percent of patients with high BVL received ribavirin, mostly without prior RAS-testing. Per protocol sustained virologic response (SVR) by low vs. high BVL was 98.8 and 95.1%. All patients with NS5A RAS achieved SVR.ConclusionsIn German, real-world most patients received elbasvir/grazoprevir without ribavirin. Ribavirin was mainly added in GT1a patients >800 000 IU/mL, who were not NS5A RAS tested. SVR rates were consistently high and comparable to clinical trial results.

An integrated analysis of elbasvir/grazoprevir in Korean patients with hepatitis C virus genotype 1b infection.

Background/AimsIn the Republic of Korea, an estimated 231,000 individuals have chronic hepatitis C virus (HCV) infection. The aim of the present analysis was to evaluate the safety and efficacy of elbasvir/grazoprevir (EBR/GZR) administered for 12 weeks in Korean patients who were enrolled in international clinical trial phase 3 studies.MethodsThis was a retrospective, integrated analysis of data from patients with HCV genotype (GT) 1b infection enrolled at Korean study sites in four EBR/GZR phase 3 clinical trials. Patients were treatment-naive or had previously failed interferon-based HCV therapy, and included those with human immunodeficiency virus coinfection or Child-Pugh class A cirrhosis. All patients received EBR 50 mg/GZR 100 mg once daily for 12 weeks. The primary endpoint was sustained virologic response at 12 weeks after completion of therapy (SVR12, HCV RNA <15 IU/mL).ResultsSVR12 was achieved by 73 of 74 (98.6%) patients. No patients had virologic failure and one discontinued from the study after withdrawing consent. SVR12 rates were uniformly high across all patient subgroups. A total of 16 patients had nonstructural protein 5A resistance-associated substitutions at baseline (16/73, 22%), all of whom achieved SVR12. Adverse events (AEs) reported in >5% of patients were fatigue (6.8%), upper respiratory tract infection (5.4%), headache (5.4%), and nausea (5.4%). Thirteen patients (17.6%) reported drug-related AEs, two serious AEs occurred, and two patients discontinued treatment owing to an AEs.ConclusionsIn this retrospective analysis, EBR/GZR administered for 12 weeks was well-tolerated and highly effective in Korean patients with HCV GT1b infection.

Real-world safety and efficacy of sofosbuvir and ledipasvir for elderly patients.

Background and AimIn September 2015, sofosbuvir and ledipasvir were approved for clinical use in Japan for patients infected with genotype 1 hepatitis C virus. We conducted a postmarketing prospective cohort study to elucidate the safety and efficacy of this therapy in a real‐world setting.MethodsWe treated 509 patients using standard doses of sofosbuvir and ledipasvir for 12 weeks. As sustained virological response (SVR) in 2 patients could not be evaluated, 507 patients were finally analyzed. Patients with daclatasvir plus asunaprevir failure were excluded.ResultsFour patients (0.8%) discontinued treatment due to adverse events. SVR rates for the overall cohort, patients <65 years old, ≥65 and <75 years old, and ≥75 years old were 98% (495/507), 98% (161/163), 96% (179/186), and 98% (155/158), respectively. SVR rates among cirrhotic patients, patients with moderate chronic kidney disease (CKD), patients with a history of hepatocellular carcinoma (HCC) treatment, patients with protease inhibitor (PI) triple therapy failure, and patients with resistance‐associated substitutions (RASs) to nonstructural protein 5A (NS5A) were 97% (228/235), 98% (117/119), 95% (95/100), 94% (46/49), and 92% (44/48), respectively. In the comparison of factors between patients with and without SVR, high body weight, discontinuation of therapy, and NS5A RASs were significantly associated with non‐SVR.ConclusionsIn this real‐world setting, sofosbuvir and ledipasvir were a safe treatment even in patients ≥75 years old. When patients without pre‐existing NS5A RASs and daclatasvir plus asunaprevir failure are selected, extremely high SVR rates can be achieved irrespective of age.

HA1077 displays synergistic activity with daclatasvir against hepatitis C virus and suppresses the emergence of NS5A resistance-associated substitutions in mice

The kinase C-related kinase 2 (PRK2), which phosphorylates hepatitis C virus (HCV) RNA polymerase, is a proviral factor enhancing HCV replication. Here, we report on the in vivo anti-HCV efficacy of HA1077, which inhibits viral genome replication by targeting PRK2 and displays viral entry inhibitory activity by targeting Rho-associated kinase. HA1077 showed synergistic antiviral activity selectively with nonstructural protein 5 A (NS5A) inhibitors including daclatasvir (DCV). HA1077 oral administration substantially reduced serum viral loads in mice bearing HCV genotype 2a-replicating Huh7 xenografts. When administered with DCV, HA1077 potentiated the antiviral efficacy of DCV and suppressed the generation of DCV resistance-associated variants (RAVs). By deep-sequencing analysis, we uncovered an unprecedented DCV-induced polymorphism at the poly-proline motif (PxxPxxP) of NS5A. Coadministration of HA1077 reduced such a polymorphism. Overall, our results demonstrate the potential therapeutic benefit of combination therapy with HA1077 plus DCV for HCV patients carrying emerging or pre-existing RAVs toward NS5A inhibitors.

Efficacy of Sofosbuvir and Velpatasvir, With and Without Ribavirin, in Patients With Hepatitis C Virus Genotype 3 Infection and Cirrhosis

In phase 3 trials and real-world settings, smaller proportions of patients with genotype 3 hepatitis C virus (HCV) infection and cirrhosis have a sustained virologic response 12 weeks after treatment (SVR12) with the combination of sofosbuvir and velpatasvir than in patients without cirrhosis. It is unclear whether adding ribavirin to this treatment regimen increases SVRs in patients with genotype 3 HCV infection and cirrhosis. We performed a phase 2 trial of 204 patients with genotype 3 HCV infection and compensated cirrhosis (mean age 51 ± 7.4 years) at 29 sites in Spain from August 19, 2016 through April 18, 2017. Patients were assigned to groups given sofosbuvir and velpatasvir for 12 weeks (n= 101) or sofosbuvir and velpatasvir plus ribavirin for 12 weeks (n= 103). The primary efficacy end point was SVR12. The overall rates of SVR12 were 91% (92 of 101; 95% CI 84-96) for the sofosbuvir-velpatasvir group and 96% (99 of 103; 95% CI 90-99) for the sofosbuvir-velpatasvir plus ribavirin group. In the sofosbuvir-velpatasvir group, a smaller proportion of patients with baseline resistance-associated substitutions (RASs) in nonstructural protein 5A (NS5A) achieved an SVR12 (84%) than did patients without (96%). In the sofosbuvir-velpatasvir plus ribavirin group, baseline RASs had less effect on the proportion of patients with an SVR12 (96% for patients with baseline RASs; 99% for patients without). The most common adverse events (which occurred in ≥10% of patients) were asthenia (12%) in the sofosbuvir-velpatasvir group and asthenia (27%), headache (24%), and insomnia (12%) in the sofosbuvir-velpatasvir plus ribavirin group. Consistent with findings from previous studies, a high rate of patients (91% and 96%) with genotype 3 HCV infection and compensated cirrhosis achieved an SVR12 with sofosbuvir and velpatasvir, with or without ribavirin. Of patients treated with sofosbuvir and velpatasvir without ribavirin, fewer patients with baseline NS5A RASs achieved an SVR12 compared with patients without baseline NS5A. ClinicalTrials.govNCT02781558.

High efficacy of sofosbuvir/velpatasvir and impact of baseline resistance‐associated substitutions in hepatitis C genotype 3 infection

Twelve weeks of the pangenotypic direct-acting antiviral (DAA) combination sofosbuvir/velpatasvir (SOF/VEL) was highly efficient in patients with hepatitis C virus (HCV) genotype 3 (GT3) infection in the ASTRAL-3 approval study. However, presence of resistance-associated substitutions (RASs) in the HCV nonstructural protein 5A (NS5A) was associated with lower treatment response. To assess the efficacy and safety of SOF/VEL±ribavirin (RBV) and the impact of NS5A RASs and RBV use on treatment outcome in HCV GT3 infection in a real-world setting. In this multicentre cohort study, GT3 patients from ten treatment centres across Germany were included. Sustained virological response was assessed 12weeks after end-of-treatment (SVR12) in modified intention-to-treat (mITT) and per-protocol analysis (PP). NS5A RASs were tested by population-based sequencing. A total of 293 GT3 patients were included. The median age was 48years, 70% were male, 25.3% were cirrhotic, 9.2% were HCV/HIV co-infected and 21.8% were treatment-experienced, including 4.1% with DAA experience. Baseline NS5A RASs (Y93H, A30K, L31M) were detected in 11.2%. RBV was added in 5% of noncirrhotic and 58.9% of cirrhotic patients, respectively. SVR12 rates for SOF/VEL±RBV were 95.9% (mITT) and 99.5% (PP), respectively. Only 1 virological relapse occurred in a cirrhotic patient previously treated with SOF/RBV. No treatment-related major adverse events occurred. Twelve weeks of SOL/VEL±RBV was safe and highly efficient in HCV GT3 across a diverse patient population. Baseline NS5A RASs were rarely observed and presence did not seem to impact SVR, regardless of the use of RBV.

The Real-World Safety and Efficacy of Daclatasvir and Asunaprevir for Elderly Patients.

Background/AimsAlthough daclatasvir with asunaprevir was approved in Japan for interferon ineligible or intolerant patients, patients aged ≥75 years were excluded in the phase III trial. The present study aimed to evaluate the safety and efficacy of this therapy for elderly patients aged ≥75 years and to clarify whether an extremely high sustained virological response (SVR) rate can be achieved, even in a real-world setting when patients with resistance-associated substitutions (RASs) to nonstructural protein 5A (NS5A) inhibitors or prior simeprevir failure are excluded.MethodsDaclatasvir (60 mg) and asunaprevir (100 mg) were orally administered daily for 24 weeks. Patients without pre-existing NS5A RASs and simeprevir failure were enrolled in this study.ResultsOverall, 110 patients were treated. The median age was 73 years old. The SVR rates of total patients, those aged ≥75 years, and those aged <75 years were 97% (107/110), 98% (46/47), and 97% (61/63), respectively. The treatment of two patients (2%) was discontinued because of adverse events.ConclusionsDaclatasvir with asunaprevir was a safe treatment, even in patients aged ≥75 years. When patients without pre-existing NS5A RASs and prior simeprevir failure were selected, an extremely high SVR rate could be achieved irrespective of age.

Characterization of Naturally Occurring NS5A and NS5B Polymorphisms in Patients Infected with HCV Genotype 3a Treated with Direct-Acting Antiviral Agents.

Hepatitis C virus (HCV) genotype (GT)3 is associated with increased risk of steatosis, development of cirrhosis and hepatocellular carcinoma. Limited data are available regarding genetic variability and use of direct-acting antiviral agents in these patients. non-structural protein 5A (NS5A) and non-structural protein 5B (NS5B) sequencing was performed on 45 HCV GT3-infected Italian patients subsequently treated with sofosbuvir ± daclatasvir (SOF ± DCV). Novel GT3a polymorphisms were observed by Sanger sequencing in three NS5A (T79S, T107K, and T107S) and three NS5B (G166R, Q180K, and C274W) baseline sequences in patients who achieved sustained virological response (SVR). Baseline NS5A resistance-associated substitutions (RASs) A30K and Y93H were detected in 9.5% of patients; one patient with A30K did not achieve SVR. Phylogenetic analyses of sequences showed no distinct clustering. Genetic heterogeneity of NS5A and NS5B was evaluated using ultra-deep pyrosequencing (UDPS) in samples longitudinally collected in patients not achieving SVR. Some novel NS5A and NS5B polymorphisms detected at baseline may not impact treatment outcome, as they were not enriched in post-failure samples. In contrast, the clinically novel GT3 NS5A-L31F RAS emerged in one treatment failure, and I184T, G188D and N310S, located on the same NS5B haplotype, became predominant after failure. These findings suggest a potential impact of these novel substitutions on the treatment outcome; however, their significance requires further investigation.

Clinical Resistance to Velpatasvir (GS-5816), a Novel Pan-Genotypic Inhibitor of the Hepatitis C Virus NS5A Protein

Velpatasvir (VEL, GS-5816) is a novel pan-genotypic hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor with activity against genotype 1 (GT1) to GT6 HCV replicons. In a phase 1b 3-day monotherapy study, patients treated with a 150-mg dose of GS-5816 had a mean maximal HCV RNA decline of ≥3.3 log10 IU/ml in GT1a, -1b, -2, -3, and -4. This report characterizes virologic resistance to VEL in these patients. NS5A resistance-associated substitutions (RASs) were detected by deep sequencing (1% cutoff) pretreatment in 22/70 patients, i.e., 10/35 (29%) patients with GT1a, 1/8 (13%) with GT1b, 4/8 (50.0%) with GT2, 5/17 (29.4%) with GT3, and 2/2 (100.0%) with GT4. In GT1a and GT3 patients, pretreatment RASs were associated with a slightly reduced HCV RNA response compared to that of patients without pretreatment RASs; among patients with GT1b, GT2, and GT4, no significant difference in response was observed in those with or without pretreatment RASs. Following treatment, the pattern of emergent RASs was more complex for GT1a than for the other genotypes. In GT1a, substitutions emerged at positions M28, Q30, L31, P32, H58, E92, and Y93, with the most prevalent substitutions at positions Y93, M28, and L31. RASs were observed at two positions in GT1b and GT2 (Y93 and L31), three positions in GT3 (Y93, L31, and E92), and four positions in GT4 (L28, M31, P32L, and Y93). RASs that were present pretreatment persisted through the 48-week follow-up period; however, RASs emerging during treatment were more likely to decline both in prevalence and in frequency within the viral population during follow-up. (This study has been registered at ClinicalTrials.gov under registration no. NCT01740791.).