Baseline Resistance-associated Substitutions Research Articles

Molecular characterization of patients with chronic hepatitis C virus infection in Jordan: implications on response to direct-acting antiviral therapy

ObjectivesTo investigate the molecular characteristics of Hepatitis C Virus (HCV) detected in patients with chronic HCV infection in Jordan. MethodsThe study included 48 Jordanian treatment-naïve patients with active chronic HCV recruited from seven governorates. HCV genotype and the resistance-associated substitutions (RAS) profile were investigated by next-generation sequencing of the NS5B, NS5A, and NS3 regions of HCV. Results“Unusual genotype 4 subtypes” were detected in four (8.3%) patients (4n-n = 1, 4o-n = 2, 4v-n = 1); one patient (2.1%) was co-infected by genotypes 1b+4a. Overall prevalence of NS5A RASs was 38.3% (3% cutoff); genotype 4a showed the highest NS5A RAS prevalence (n = 11, 55.0%). Overall prevalence of NS3 RASs was 21.8% (7/32), all genotype 1a-infected patients. ConclusionsWe report, for the first time in Jordanian patients with chronic HCV infection, the detection of unusual genotype 4 subtypes 4n, 4o, and 4v. Baseline RASs in NS5A are frequent, with complex RASs patterns in some of the unusual subtypes. Our data support the need for sequencing surveillance programs in sub-Saharan Africa, Asia, and the Middle East and North African region to monitor response to treatment in these subtypes and to facilitate the World Health Organization's 2030 elimination strategy.

Next-generation sequencing analysis of hepatitis C virus resistance-associated substitutions in direct-acting antiviral failure in South Korea.

We used next-generation sequencing (NGS) to analyze resistance-associated substitutions (RASs) and retreatment outcomes in patients with chronic hepatitis C virus (HCV) infection who failed direct-acting antiviral agent (DAA) treatment in South Korea. Using prospectively collected data from the Korean HCV cohort study, we recruited 36 patients who failed DAA treatment in 10 centers between 2007 and 2020; 29 blood samples were available from 24 patients. RASs were analyzed using NGS. RASs were analyzed for 13 patients with genotype 1b, 10 with genotype 2, and one with genotype 3a. The unsuccessful DAA regimens were daclatasvir+asunaprevir (n=11), sofosbuvir+ribavirin (n=9), ledipasvir/sofosbuvir (n=3), and glecaprevir/pibrentasvir (n=1). In the patients with genotype 1b, NS3, NS5A, and NS5B RASs were detected in eight, seven, and seven of 10 patients at baseline and in four, six, and two of six patients after DAA failure, respectively. Among the 10 patients with genotype 2, the only baseline RAS was NS3 Y56F, which was detected in one patient. NS5A F28C was detected after DAA failure in a patient with genotype 2 infection who was erroneously treated with daclatasvir+asunaprevir. After retreatment, 16 patients had a 100% sustained virological response rate. NS3 and NS5A RASs were commonly present at baseline, and there was an increasing trend of NS5A RASs after failed DAA treatment in genotype 1b. However, RASs were rarely present in patients with genotype 2 who were treated with sofosbuvir+ribavirin. Despite baseline or treatment-emergent RASs, retreatment with pan-genotypic DAA was highly successful in Korea, so we encourage active retreatment after unsuccessful DAA treatment.

Efficacy of ultra-short, response-guided sofosbuvir and daclatasvir therapy for hepatitis C in a single-arm mechanistic pilot study.

World Health Organization has called for research into predictive factors for selecting persons who could be successfully treated with shorter durations of direct-acting antiviral (DAA) therapy for hepatitis C. We evaluated early virological response as a means of shortening treatment and explored host, viral and pharmacokinetic contributors to treatment outcome. Duration of sofosbuvir and daclatasvir (SOF/DCV) was determined according to day 2 (D2) virologic response for HCV genotype (gt) 1- or 6-infected adults in Vietnam with mild liver disease. Participants received 4- or 8-week treatment according to whether D2 HCV RNA was above or below 500 IU/ml (standard duration is 12 weeks). Primary endpoint was sustained virological response (SVR12). Those failing therapy were retreated with 12 weeks SOF/DCV. Host IFNL4 genotype and viral sequencing was performed at baseline, with repeat viral sequencing if virological rebound was observed. Levels of SOF, its inactive metabolite GS-331007 and DCV were measured on days 0 and 28. Of 52 adults enrolled, 34 received 4 weeks SOF/DCV, 17 got 8 weeks and 1 withdrew. SVR12 was achieved in 21/34 (62%) treated for 4 weeks, and 17/17 (100%) treated for 8 weeks. Overall, 38/51 (75%) were cured with first-line treatment (mean duration 37 days). Despite a high prevalence of putative NS5A-inhibitor resistance-associated substitutions (RASs), all first-line treatment failures cured after retreatment (13/13). We found no evidence treatment failure was associated with host IFNL4 genotype, viral subtype, baseline RAS, SOF or DCV levels. Shortened SOF/DCV therapy, with retreatment if needed, reduces DAA use in patients with mild liver disease, while maintaining high cure rates. D2 virologic response alone does not adequately predict SVR12 with 4-week treatment. Funded by the Medical Research Council (Grant MR/P025064/1) and The Global Challenges Research 70 Fund (Wellcome Trust Grant 206/296/Z/17/Z).

Effectiveness of elbasvir/grazoprevir plus ribavirin for hepatitis C virus genotype 1a infection and baseline NS5A resistance

Introduction and ObjectivesIn clinical trials, patients with hepatitis C virus (HCV) genotype (GT)1a infection and baseline resistance-associated substitutions (RASs) at amino acid positions 28, 30, 31, or 93 receiving elbasvir/grazoprevir for 12 weeks achieved lower rates of sustained virologic response (SVR) than those without baseline RASs. SVR rates in patients with RASs were improved when elbasvir/grazoprevir treatment duration was extended from 12 to 16 weeks and administered concomitantly with ribavirin. Materials and MethodsThis was a retrospective, observational analysis using electronic health record abstraction. Patients with HCV GT1a infection and RASs at positions 28, 30, 31, or 93 who were prescribed 16 weeks of elbasvir/grazoprevir and ≥ 1 prescription for ribavirin were included. SVR was defined as HCV RNA below the lower limit of quantification ≥ 70 days after end of treatment. ResultsThe primary analysis included patients with baseline RASs at positions 30, 31, or 93 (n = 76); a secondary analysis included patients with RASs at positions 28, 30, 31, or 93 (n = 93). SVR was achieved by 77.6% (59/76) of patients in the primary analysis and 80.6% (75/93) of those in the secondary analysis. Of the 18 (19.4%) patients in the secondary cohort who failed to achieve SVR, 8 relapsed (4 with treatment-emergent NS5A substitutions) and 10 did not have viral sequencing to distinguish relapse from reinfection. ConclusionsThis analysis highlights the opportunities in leveraging real-world data to further understand treatment outcomes in smaller, discrete subgroups of patients with HCV infection who cannot be thoroughly evaluated in clinical trials.

High real-world effectiveness of 12-week elbasvir/grazoprevir without resistance testing in the treatment of patients with HCV genotype 1a infection in Norway

Background and aims The recommended treatment duration of hepatitis C virus (HCV) genotype 1a (GT1a) infection with elbasvir/grazoprevir (EBR/GZR) in the presence of a high baseline viral load and resistance associated substitutions (RAS) is 16 weeks with ribavirin added. The objective of this study was to evaluate the real-world effectiveness of 12 weeks of EBR/GZR without ribavirin and regardless of baseline viral load and RAS testing. Method This retrospective, observational cohort study was performed at five Norwegian hospitals that did not systematically utilize RAS testing. All adult patients with chronic HCV GT1a and compensated liver disease who had received 12 weeks of EBR/GZR without ribavirin and baseline RAS testing, were included. The primary endpoint was sustained virologic response at week 12 (SVR12), or if not available, at week 4 (SVR4). Results We included 433 patients and attained SVR data on 388. The mean age was 45.7 years (22–73 years). 67.2% were male. HIV co-infection was present in 3.8% (16/424) and cirrhosis in 4% (17/424). The viral load was >800 000 IU/mL in 55.0% (235/427) of patients. Overall SVR was achieved in 97.2% (377/388). SVR was achieved in 98.3% (169/172) of those with viral load ≤800 000 IU/mL and in 96.2% (202/210) of those with viral load >800 000 IU/mL. Conclusion We observed high SVR rates among patients with HCV GT1a infection treated with EBR/GZR for 12 weeks without ribavirin, with no regard to baseline viral load and no RAS testing.

Efficacy and safety of sofosbuvir/velpatasvir with or without ribavirin in hepatitis C genotype 3 compensated cirrhosis: A meta-analysis

BACKGROUNDHepatitis C virus (HCV) is a leading cause of liver cirrhosis and hepatocellular carcinoma globally. Sofosbuvir/velpatasvir (SOF/VEL) is an effective pan-genotypic direct-acting antiviral combination for treatment of chronic HCV infection. While the addition of ribavirin (RBV) to SOF/VEL improved sustained virological response (SVR12) in genotype 3 (GT3) decompensated cirrhosis patients, the benefits of RBV in GT3 compensated cirrhosis patients receiving SOF/VEL remains unclear. AIMTo evaluate the efficacy and safety of SOF/VEL, with or without RBV in GT3 compensated cirrhosis patients. METHODSWe searched four electronic databases (PubMed/Medline, Embase, Cochrane Library and Web of Science) from inception up to June 2021 using both free text and MeSH terms. There was no restriction on language, geography, publication dates and publication status (full text or abstracts). All GT3 compensated cirrhosis patients treated with 12 wk of SOF/VEL, with or without RBV, were included, regardless of age, gender or prior treatment experience. The primary outcome was sustained virological response 12-wk post-treatment (SVR12). The secondary outcome was treatment-related adverse events, as defined by symptomatic anemia requiring transfusion or a drop in hemoglobin beyond 2 g/dL. The pooled relative risk (RR), 95%CI and heterogeneity (I2) were estimated using Review Manager version 5.3.RESULTSFrom 1752 citations, a total of seven studies (2 randomized controlled trials, 5 cohort studies) with 1088 subjects were identified. The SVR12 was similar in GT3 compensated cirrhosis patients, regardless of the use of RBV, for both the intention-to-treat RR 1.03, 95%CI: 0.99-1.07; I2 = 0%) and the per-protocol analysis (RR: 1.03, 95%CI: 0.99-1.07; I2 = 48%). The overall pooled rate of treatment-related adverse events was 7.2%. Addition of RBV increased the pooled risk of treatment-related adverse events in GT3 compensated cirrhosis patients receiving SOF/VEL (RR: 4.20, 95%CI: 1.29-13.68; I2 = 0%). Subgroup analysis showed that RBV was associated with a higher SVR12 in GT3 compensated cirrhosis patients with baseline resistance-associated substitutions. However, addition of RBV did not significantly increase the SVR12 among treatment-experienced GT3 compensated cirrhosis patients. CONCLUSIONRibavirin was not associated with higher SVR12 in GT3 compensated cirrhosis patients receiving SOF/VEL. Our findings suggest a limited role for RBV as routine add-on therapy to SOF/VEL in GT3 compensated cirrhosis patients.

Impact of direct-acting antiviral regimens on hepatic and extrahepatic manifestations of hepatitis C virus infection

Hepatitis C virus (HCV) is a common cause of liver disease and is associated with various extrahepatic manifestations (EHMs). This mini-review outlines the currently available treatments for HCV infection and their prognostic effect on hepatic manifestations and EHMs. Direct-acting antiviral (DAA) regimens are considered pan-genotypic as they achieve a sustained virological response (SVR) > 85% after 12 wk through all the major HCV genotypes, with high percentages of SVR even in advanced fibrosis and cirrhosis. The risk factors for DAA failure include old males, cirrhosis, and the presence of resistance-associated substitutions (RAS) in the region targeted by the received DAAs. The effectiveness of DAA regimens is reduced in HCV genotype 3 with baseline RAS like A30K, Y93H, and P53del. Moreover, the European Association for the Study of the Liver recommended the identification of baseline RAS for HCV genotype 1a. The higher rate of hepatocellular carcinoma (HCC) after DAA therapy may be related to the fact that DAA regimens are offered to patients with advanced liver fibrosis and cirrhosis, where interferon was contraindicated to those patients. The change in the growth of pre-existing subclinical, undetectable HCC upon DAA treatment might be also a cause. Furthermore, after DAA therapy, the T cell-dependent immune response is much weaker upon HCV clearance, and the down-regulation of TNF-α or the elevated neutrophil to lymphocyte ratio might increase the risk of HCC. DAAs can result in reactivation of hepatitis B virus (HBV) in HCV co-infected patients. DAAs are effective in treating HCV-associated mixed cryoglobulinemia, with clinical and immunological responses, and have rapid and high effectiveness in thrombocytopenia. DAAs improve insulin resistance in 90% of patients, increase glomerular filtration rate, and decrease proteinuria, hematuria and articular manifestations. HCV clearance by DAAs allows a significant improvement in atherosclerosis and metabolic and immunological conditions, with a reduction of major cardiovascular events. They also improve physical function, fatigue, cognitive impairment, and quality of life. Early therapeutic approach with DAAs is recommended as it cure many of the EHMs that are still in a reversible stage and can prevent others that can develop due to delayed treatment.

Hepatitis C virus treatment failure: Clinical utility for testing resistance-associated substitutions.

The hepatitis C virus has a high mutation capacity that leads to the emergence of resistance-associated substitutions (RAS). However, the consequence of resistance selection during new direct-acting antiviral drug (DAA) treatment is not necessarily the therapeutic failure. In fact, DAA treatment has shown a high rate (> 95%) of sustained virological response even when high baseline RAS prevalence has been reported. In the context of RAS emergence and high rates of sustained viral response, the clinical relevance of variants harboring RAS is still controversial. Therefore, in order to summarize the data available in international guidelines, we have reviewed the clinical utility of testing RAS in the era of new pangenotypic DAA drugs.

Prevalence of resistance-associated substitutions and phylogenetic analysis of hepatitis C virus infection in Russia

ObjectivesDue to limited hepatitis C virus (HCV) sequence availability from patients in Russia, the relationship between subtypes and baseline resistance-associated substitutions (RAS) to direct antiretroviral treatment outcome is not fully understood. MethodsDeep sequencing of HCV NS3, NS5A, and NS5B sequences was performed on plasma HCV samples from 412 direct-acting antiviral (DAA)-naïve patients from Russia. Phylogenetic analysis was performed to investigate sequence similarities between HCV strains from Russia, Asia, Europe, and North America. Pretreatment HCV RAS was assessed with a 15% cutoff. ResultsHCV genotype GT1b and GT3a sequences in Russia were related to strains in Europe and Asia. The prevalence of GT1a and GT2a was low in Russia. In GT1b, the prevalence of NS5A Y93H was lower in Russia (6%) compared with Asia (15%). The prevalence of NS5B L159F was similar between Russia and Europe (26–39%). GT3a RAS prevalence was similar between Russia and Asia, Europe, and North America. The 2k/1b recombinant strain in Russia was related to strains from Europe. A higher prevalence of the NS5A RAS L31M (10%) was observed in 2k/1b sequences compared to GT1b (1–6%). ConclusionsThe prevalence of RASs and the phylogenetic analysis showed similarities in HCV strains between Russia, Europe, and North America. This information may be useful for HCV regimens in Russia.

Inferior cure rate in pilot study of 4-week glecaprevir/pibrentasvir treatment with or without ribavirin of chronic hepatitis C.

Shortening the treatment duration for chronic hepatitis C may increase feasibility and reduce the cost of cure. The aims of this study were to compare 4weeks of glecaprevir/pibrentasvir (GLE/PIB) treatment with and without ribavirin for patients with chronic hepatitis C and favourable baseline characteristics and to monitor the development of resistance-associated substitutions (RAS) and re-treatment outcomes if treatment failed. We performed an open-label single-centre randomized controlled trial, in which patients with chronic hepatitis C were randomized 1:1 to GLE/PIB±ribavirin, stratified by genotype 3. The main inclusion criteria were treatment-naive patients, aged 18-49 with all genotypes accepted, and absence of liver fibrosis, determined by liver stiffness measurement less than 8kPa. Viral genome sequences were determined by deep sequencing at baseline and at the time of relapse. A total of 32 patients started treatment. Sustained virological response at week 12 (SVR12) was 59% (10/17) for GLE/PIB without ribavirin and 73% (11/15) for GLE/PIB with ribavirin. Drug target-specific NS5A RAS were detected at baseline for 45% (5/11) of patients with treatment failure and for 14% (3/21) of patients who achieved SVR12. Ten failure patients were retreated 12weeks with sofosbuvir-based regimens; all have been cured. In this pilot study of 4-week treatment with GLE/PIB with and without ribavirin, we found that baseline RAS were more frequent in patients with virological failure. Development of RAS did occur after short treatment but did not result in retreatment failure with a different regimen. EudraCT no: 2017-005179-21.

Naturally Occurring Resistance Associated Substitutions in Non-Cirrhotic, Treatment Naive HCV-HIV Co-Infected Patients Does Not Affect the Treatment Response for Anti-HCV Antiviral Therapy.

PurposeLimited literature on the prevalence of baseline resistance associated substitutions (BL-RAS) among HCV–HIV co-infected patients and their association with treatment outcomes is available especially from India. Hence, the present study aimed to study naturally occurring RAS among non-cirrhotic HCV–HIV co-infected patients and their impact on the response to anti-HCV therapy.Patients and MethodsIn this retrospective study, archived blood samples of 80 HCV–HIV co-infected patients, before anti-HCV therapy initiation, were tested for substitutions at the drug acting sites (NS5a and NS5b) in the HCV genome by direct PCR sequencing.ResultsBL-RAS were seen in 19 (23.7%) patients. As well as BL-RAS, all patients were given sofosbuvir (SOF) 400 mg+ daclatasvir (DCV) 60 mg for 12 weeks. Overall, sustained virological response (SVR) was achieved in 63 (78.8%) patients, in 13 with BL-RAS and in 50 without BL-RAS. All the SVR failure cases (n=17) were retreated with SOF (400 mg) +DCV (60 mg)+ ribavirin (RBV) for 24 weeks. SVR was eventually attained in 14 (82.3%) patients, in 4/6 (66.6%) with BL-RAS and in 10/11 (91%) without BL-RAS. On univariate analysis, age more than 30 years (OR: 11.6; 95% CI: 3.0–45.5, p-value<0.001) and female gender (OR: 8.6; 95% CI: 1.1−69, p-value <0.009) were found to be significant factors associated with the attainment of SVR.ConclusionBL-RAS are common in HCV–HIV co-infected patients. The existence of BL-RAS, however, did not affect the attainment of SVR among non-cirrhotic, treatment naive HCV–HIV co-infected patients.

NS34A resistance-associated substitutions in chronic hepatitis C in Upper Egypt and regression of liver fibrosis after direct-acting antiviral therapy

BackgroundViral resistance-associated substitutions (RASs) can develop in the setting of DAAs therapy (i.e., emerging RASs). Long-term monitoring of fibrosis regression after achieving SVR to simiprevir (SMV)/sofosbuvir (SOF) is essential. The aim of this study was to determine the prevalence of baseline and emerging NS34A RASs in chronic HCV patients in Upper Egypt and to assess the impact of SMV/SOF therapy on liver stiffness.ResultsThe enrolled 59 patients had HCV genotype 4a without any baseline RASs in the NS34A region. 96.6% (57/59) of patients achieved sustained virological response (SVR12). Of the two patients who failed to achieve SVR12, one of them developed emerging RASs Q80K in the NS34A region. Seventy-two weeks after SMV/SOF therapy, the percentage of patients with liver fibrosis stage (F2, F3, and F4) decreased from 75.4% before treatment to 42.1% after treatment. The combination of SOF and SMV appeared to be well tolerated.ConclusionsAll patients had HCV genotype 4a without any baseline RASs in the NS34A region. In addition, there was improvement of non-invasive measures of liver fibrosis in patients who achieved SVR, 72 weeks after SMV/SOF therapy.

Effect of Baseline Resistance-Associated Substitutions on Thalassemia Patients with Chronic HCV Infection: A Two-Year Follow-Up.

BACKGROUND Direct-acting antivirals (DAAs) against hepatitis C virus (HCV) infection showed the presence of resistant-associated substitutions (RASs). The aim of the present study was to carry out a follow-up of patients with baseline RASs to report the impact of RASs on DAA therapy outcome.METHODS In a cohort study, we analyzed NS5A and NS5B RASs among nine thalassemia cases by baseline RASs. In a 2-year follow-up, we analyzed viral markers and biochemical and hematological parameters of the participants and their sustained virologic response (SVR). Statistical analyses were performed using SPSS software version 22.RESULTS RASs for HCV subtype 1a included M28V, L31M, and H58P. For subtype 1b: L28M, R30Q, S24F, and C316N. And for subtype 3a: C316S, and S24F. In patients with cirrhosis (n = 5), ALT (p = 0.001) and AST (p = 0.007) levels were significantly reduced after treatment, and creatinine level slightly increased (p = 0.025). However, no significant data was observed in non-cirrhotic patients following the treatment. CONCLUSION The present study did not show any adverse effects of DAA therapy among patients with thalassemia suffering from chronic HCV infection with baseline RASs. Furthermore, reduction in ferritin and liver stiffness levels after DAA therapy could show the efficacy of DAA in such patients.

Global evolutionary analysis of chronic hepatitis C patients revealed significant effect of baseline viral resistance, including novel non-target sites, for DAA-based treatment and retreatment outcome.

Direct-acting antivirals (DAAs) have proven highly effective against chronic hepatitis C virus (HCV) infection. However, some patients experience treatment failure, associated with resistance-associated substitutions (RASs). Our aim was to investigate the complete viral coding sequence in hepatitis C patients treated with DAAs to identify RASs and the effects of treatment on the viral population. We selected 22 HCV patients with sustained virologic response (SVR) to match 21 treatment-failure patients in relation to HCV genotype, DAA regimen, liver cirrhosis and previous treatment experience. Viral-titre data were compared between the two patient groups, and HCV full-length open reading frame deep-sequencing was performed. The proportion of HCV NS5A-RASs at baseline was higher in treatment-failure (82%) than matched SVR patients (25%) (p= .0063). Also, treatment failure was associated with slower declines in viraemia titres. Viral population diversity did not differ at baseline between SVR and treatment-failure patients, but failure was associated with decreased diversity probably caused by selection for RAS. The NS5B-substitution 150V was associated with sofosbuvir treatment failure in genotype 3a. Further, mutations identified in NS2, NS3-helicase and NS5A-domain-III were associated with DAA treatment failure in genotype 1a patients. Six retreated HCV patients (35%) experienced 2nd treatment failure; RASs were present in 67% compared to 11% with SVR. In conclusion, baseline RASs to NS5A inhibitors, but not virus population diversity, and lower viral titre decline predicted HCV treatment failure. Mutations outside of the DAA targets can be associated with DAA treatment failure. Successful DAA retreatment in patients with treatment failure was hampered by previously selected RASs.

Effect of baseline resistance-associated substitutions on the efficiency of glecaprevir/pibrentasvir in chronic hepatitis C subjects: A meta-analysis.

The effect of baseline resistance-associated substitutions on the sustained virologic response at 12weeks in chronic hepatitis C subjects has drawn considerable attention. However, it has been reported that the relationship between such substitutions and sustained virologic response at 12weeks in chronic hepatitis C subjects is variable in different treatments. This meta-analysis was performed to evaluate this relationship in subjects treated with glecaprevir/pibrentasvir. A systematic literature search up to May 2020 was done, and 17 studies were identified with 6501 chronic hepatitis C subjects. They were reporting relationships between baseline resistance-associated substitutions and sustained virologic response at 12weeks in chronic hepatitis C subjects treated with glecaprevir/pibrentasvir. The odds ratio (OR) with 95% confidence intervals (CIs) was calculated to evaluate the prognostic role of baseline resistance-associated substitutions on the sustained virologic response at 12weeks in chronic hepatitis C subjects treated with glecaprevir/pibrentasvir using the dichotomous method with a random or fixed-effect model. Lower sustained virologic response at 12weeks post-treatment in chronic hepatitis C subjects was significantly related to baseline resistance-associated substitutions in overall genotypes (OR, 0.03; 95% CI, 0.15-0.61, P<.001), baseline NS5a resistance-associated substitutions in genotype-1 (OR, 0.16; 95% CI, 0.04-0.57, P=.005), baseline resistance-associated substitutions in genotype-3 (OR, 0.14; 95% CI, 0.05-0.38, P<.001), and baseline NS5a resistance-associated substitutions in genotype-3 (OR, 0.21; 95% CI, 0.09-0.49, P<.001). Sustained virologic response at 12weeks in chronic hepatitis C subjects was not significantly related to the baseline NS5a resistance-associated substitutions (OR, 0.61; 95% CI, 0.17-2.22, P=.45), and baseline resistance-associated substitutions in genotype-1 (OR, 0.35; 95% CI, 0.12-1.088, P=.07). In conclusion, the impact of baseline resistance-associated substitutions on the sustained virologic response at 12weeks in chronic hepatitis C subjects treated with glecaprevir/pibrentasvir may have a great prognostic effect, especially in genotype-3 as a tool to improve treatment prediction. Chronic hepatitis C subjects with baseline resistance-associated substitutions may have an independent risk relationship with poor treatment outcomes. This relationship forces us to recommend testing prior to treatment selection to avoid any possible treatment failure.

Twelve weeks of ledipasvir/sofosbuvir all-oral regimen for patients with chronic hepatitis C genotype 2 infection: Integrated analysis of three clinical trials.

The combination of ledipasvir and sofosbuvir (LDV/SOF) has been approved for the treatment of various hepatitis C virus (HCV) genotypes across many countries. This article presents an integrated analysis of three prospective phase II/III trials in the Asia-Pacific region to evaluate the efficacy and safety of 12weeks of LDV/SOF in HCV genotype 2 patients without cirrhosis or with compensated cirrhosis. A total of 200 patients were included in the integrated analysis. The primary end-point was the rate of sustained virologic response for 12weeks after the end of therapy (SVR12), analyzed by fibrosis stage, treatment history, HCV genotype subtype, and presence of baseline resistance-associated substitutions (RAS). Safety was evaluated by adverse events and laboratory abnormalities. Twelve weeks of treatment with LDV/SOF was associated with high SVR12 rates (overall 98%) in patients with genotype 2 HCV, irrespective of fibrosis stage, treatment history, genotype 2 subtype, and presence of baseline non-structural protein 5A resistance-associated substitution (NS5A RAS), and LDV/SOF was well tolerated. Twelve weeks of treatment with LDV/SOF provides a highly effective and safe treatment for patients with genotype 2 HCV, including those with advanced fibrosis. As a ribavirin-free and protease inhibitor-free regimen with minimal on-treatment monitoring requirements, LDV/SOF can potentially play a crucial role in achieving the WHO's goal of HCV elimination.

Epidemic history and baseline resistance to NS5A-specific direct acting drugs of hepatitis C virus in Spain

Hepatitis C virus (HCV) infection remains a global health problem. Previously, the prevalence of NS5A resistance-associated substitutions (RASs) to elbasvir, a new direct-acting antiviral (DAA) against the NS5A viral protein was assessed by our group before its introduction into clinical use in Spain. However, the origin, epidemic history, transmission dynamics, diversity and baseline RASs to NS5A direct-acting agents of HCV-GT1a in Spain remain unknown. A nationwide cross-sectional survey of individuals chronically-infected with HCV-G1a and DAAs-naïve was performed. HCV population sequencing, phylogenetic analysis and Bayesian methods were used. GT1a clade II was more prevalent than clade I (82.3% vs. 17.7%; P < 0.001) and older (estimated origin in 1912 vs. 1952). Clade II epidemic is currently declining whereas clade I epidemic has reached equilibrium. A total of 58 single RASs were identified, which account for the moderate level (10%) of baseline resistance observed. When considering the regional data, marked differences were observed, with thirteen regions showing an intermediate level (5–15%) and one a high level (20%) of resistance. Current HCV-GT1a epidemic in Spain is driven by clade I which seem to have different dissemination routes relative to clade II. A moderate level of baseline RASs to NS5A-DAAs with marked differences among regions was observed. Close surveillance of response to treatment with DAAs will be important.

The Z-Profile Study: a multicenter, retrospective cohort study toassess the real-world use and effectiveness of elbasvir/grazoprevir in Canadian adult patients with chronic hepatitis C.

Canada was the first country to approve elbasvir/grazoprevir (EBR/GZR) for the treatment of chronic HCV infection for genotypes 1 and 4 with or without ribavirin and genotype 3 with sofosbuvir, with no recommendation for baseline resistance testing. The aim of this study was to describe the effectiveness of EBR/GZR and the profile of patients selected for treatment in a Canadian real-world setting. This multicenter retrospective study of HCV-infected patients treated with EBR/GZR took place among selected Canadian health care providers, with no exclusion criteria. Primary outcome measures included parameters associated with patient profile and sustained virologic response at 12 weeks (SVR12) and 24 weeks after treatment. A total of 408 patients were included; 244 had available SVR12 information (per-protocol population [PP]). Genotype distribution included 1a (54.7%), 1b (17.2%), 3(11.8%), 4 (10.0%), and other (6.4%). The majority (88.7%) of participants were treated for 12 weeks without ribavirin. Fifty-nine (14.5%) participants, predominantly with genotype 1a (49/59) infection, were tested for baseline resistance-associated substitutions (bRAS). SVR12 was achieved by 95.9% of the PP. In an exploratory analysis assessing potential predictors of SVR12, participants who had undergone bRAS testing (OR 0.14, 95% CI 0.03-0.64) and participants who had undergone liver transplant (OR 0.05, 95% CI 0.00-0.68) had significantly lower odds of achieving SVR12. This study supports the real-world effectiveness of EBR/GZR-including a broad range of genotypes and diverse fibrosis stages-in the absence of bRAS testing and in special populations.

Treatment outcomes in hepatitis C virus genotype 1a infected patients with and without baseline NS5A resistance-associated substitutions.

The presence of baseline resistance-associated substitutions (RASs) reduced sustained virologic response (SVR) rates in chronic hepatitis C virus (HCV) genotype 1a infected patients treated with Elbasvir/Grazoprevir (EBR/GZR). This study aimed to evaluate the frequency of NS5A RASs and treatment outcomes in patients for whom EBR/GZR was intended. We sequenced NS5A in 832 samples from German genotype1a-infected DAA-naïve patients population-based, which were collected in the European Resistance Database. Treatment outcomes and clinical parameters were evaluated in 519 of these patients retrospectively. Overall, 6.5% of patients harbored EBR-specific NS5A RASs at baseline, including Q30H/R (3.3%), L31M (1.8%), Y93H (1.6%) and other individual variants. Antiviral treatment, including EBR/GZR, was initiated in 88% of patients. In the absence of RASs, the majority of patients received EBR/GZR for 12 weeks (57%) and the SVR rate was 97% compared to 99% SVR achieved using other DAA regimens (LDV/SOF±RBV, G/P, PrOD+RBV, VEL/SOF). Various regimens were used in the presence of RASs and SVR rates were high following treatment with LDV/SOF (100%), G/P (83%), PrOD/RBV (100%), VEL/SOF (100%), SMV/SOF (100%) and EBR/GZR+RBV for 16 weeks (100%). However, two patients received EBR/GZR for 16 weeks without RBV and one relapsed. EBR/GZR treatment with or without RBV for 12 or 16 weeks according to a baseline RAS analysis was highly effective with ≥97% SVR in patients with genotype 1a. EBR/GZR without RBV should be avoided in patients with RASs. High SVR rates were also achieved using other 8 or 12 weeks DAA regimens.

Molecular characterization of hepatitis C virus for subtype determination and resistance-associated substitutions detection among Chinese voluntary blood donors

BackgroundThe high prevalence of hepatitis C virus (HCV) infection and the resulting burden of the disease are significant issues to public health worldwide. Although direct-acting antiviral drugs (DAAs) with good tolerance and bioavailability are available, resistance-associated substitutions (RASs) often jeopardize the successful sustainment of virological responses in HCV treatment. High-frequency baseline RASs in treatment-naïve patients can lead to failures in DAA treatment. Clinical data on HCV RASs in patients from China are limited and require investigations. Methods262 HCV RNA positive plasma from Chinese blood donors were genotyped and amplified with subtype-specific primers for NS3 and NS5A regions. RASs were analyzed using Geno2pheno. The codon usage of each resistance-associated substitution was calculated for genetic barrier analysis. ResultsThe two main subtypes in mainland China were 1b and 2a, followed by subtype 6a, 3b, 3a, and 1a. In NS3 region of 1b subtype, substitutions (T54S, V55A, Y56F, Q80 K/L, S122 G/T, R117 H/C, V170I and S174A) were present in 89.7% (96/107) of the samples. Other RASs (M28L, R30Q, P58 L/S and Y93H) were observed in 22.1% (25/113) of the samples in NS5A region. A crucial RAS, Q80K, and two other mutations (S122G + V170I) was identified in the same sequence, which reduced its susceptibility to protease inhibitor ASV and resulted in resistance to SMV. In NS5A, Y93H was detected in 9.7% (11/113) of the 1b samples, leading to medium-to-high level resistance to all six commercialized NS5A inhibitors. S122G-NS3 and Y93H-NS5A occurred simultaneously in 38.1% (7/22) of the samples with mutations in both two regions. Moreover, codon usage of S122G-NS3 and Y93H-NS5A revealed that both variants had the lowest genetic barrier and required only one transition to confer resistance. ConclusionsLow genetic barriers facilitated the generation of resistance mutants and threated the efficacy of DAA regimens. The baseline RASs posed a great challenge to real-world DAA application.