Daclatasvir plus asunaprevir for chronic HCV genotype 1b infection

Cluster analysis of hepatocellular carcinoma prognosis using preoperative alpha-fetoprotein and des-gamma-carboxy prothrombin levels: a multi-institutional study

BACKGROUND

Hepatocellular carcinoma (HCC) remains the leading cause of cancer-related mortality worldwide and is characterized by high recurrence rates after curative resection. The tumor markers des-gamma-carboxy prothrombin (DCP) and alpha-fetoprotein (AFP) are crucial for HCC diagnosis and prognosis. However, their roles in the modern era of HCC epidemiology require reevaluation.

METHODS

This multi-institutional retrospective study analyzed 1515 patients who underwent hepatectomy for primary HCC. Patients were classified into 4 clusters using k-means analysis based on preoperative DCP and AFP levels. Clinicopathologic characteristics, overall survival (OS), and recurrence rate (RR) were evaluated using Cox proportional hazards models and area under the receiver operating characteristic curve (AUROC) comparisons.

RESULTS

Cluster 3 (concurrent elevations of DCP and AFP) had the poorest 5-year OS (52.8%) and the highest RR (79.3%), whereas cluster 4 (low levels of both markers) had the most favorable outcomes, with a 5-year OS rate of 71.5% and an RR of 55.7%. Cluster 1 (elevated DCP alone) was associated with larger tumors (median of 45 mm) and more frequent vascular invasion (43%) than cluster 2 (elevated AFP alone, median tumor size of 24 mm, and vascular invasion of 36%). DCP was a stronger predictor of 5-year OS in patients with preserved liver function (AUROC, 0.63), whereas AFP was more effective in stratifying RR in patients with impaired liver function (AUROC, 0.57). Non-B, non-C hepatitis (NBNC)-related HCC exhibited a distinct biomarker profile, with an elevated DCP level correlating with a higher 5-year RR (67%) than other etiologies.

CONCLUSION

Our study introduces tumor marker clustering as a novel analytical approach, providing a nuanced understanding of AFP and DCP's combined utility in predicting prognosis and recurrence. Our findings highlight the independent and complementary roles of these biomarkers, particularly in NBNC-related HCC and in cases with impaired liver function. AFP and DCP remain crucial tools for recurrence risk assessment, guiding personalized management strategies, such as surveillance, neoadjuvant therapies, and tailored postoperative interventions.

The challenge of treating hepatitis C virus infection in children with comorbidities

Direct-acting antivirals (DAAs) have revolutionized hepatitis C virus (HCV) treatment and enabled the treatment of those who could not be treated using interferon. The aim of this work was to assess the efficacy and safety of oral DAAs in HCV-infected children with associated comorbidities. This analytical retrospective study included children with HCV mono-infection versus those with associated comorbidities. The study included 187 HCV-infected children aged 6-18 years; 114 patients (61%) had associated comorbidities. The most frequent comorbidities were hematological disorders (30.7%), followed by renal and cardiac diseases. Baseline total bilirubin, aspartate aminotransferase, and gamma glutamyl transpeptidase were significantly more elevated in patients with comorbidities. Sustained virologic response (SVR) was achieved in 100% of patients with HCV mono-infection versus 98.2% of patients with comorbidities. The most frequently reported treatment adverse effects were headache, asthenia, and irritability. All side effects were transient and did not necessitate treatment discontinuation.

CONCLUSION

DAAs allowed treatment of HCV-infected children with comorbidities with high SVR and excellent safety profile. Treatment with sofosbuvir/ledipasvir achieved an SVR of 98.9% in HCV-infected children with comorbidities. Treatment was safe and well tolerated with mild transient adverse events.

WHAT IS KNOWN

• The novel DAAs have revolutionized the landscape of HCV treatment and enabled the treatment of those who could not be treated using IFN. • When treating HCV, clinicians should take into consideration the presence of other comorbid conditions. In the IFN-RBV era, many HCV patients with comorbidities were ineligible for therapy.

WHAT IS NEW

• There are limited data in the literature about the efficacy and tolerability of DAAs in children with comorbidities. • We reported in the current study that DAAs allowed treatment of HCV-infected children with comorbidities with high SVR and excellent safety profile. These patients should be offered treatment with oral DAAs to help decrease the infectious pool and hence reach the ambitious final goal of global eradication.

Analysis of the susceptibility of refractory hepatitis C virus resistant to nonstructural 5A inhibitors

Resistance-associated substitutions (RASs) of hepatitis C virus (HCV) affect the efficacy of direct-acting antivirals (DAAs). In this study, we aimed to clarify the susceptibility of the coexistence of nonstructural (NS) 5A Q24K/L28M/R30Q (or R30E)/A92K RASs, which were observed in patients with DAAs re-treatment failure and to consider new therapeutic agents. We used a subgenomic replicon system in which HCV genotype 1B strain 1B-4 was electroporated into OR6c cells derived from HuH-7 cells (Wild-type [WT]). We converted WT genes to NS5A Q24K/L28M/R30Q/A92K or Q24/L28K/R30E/A92K. Compared with the WT, the Q24K/L28M/R30Q/A92K RASs was 36,000-fold resistant to daclatasvir, 440,000-fold resistant to ledipasvir, 6300-fold resistant to velpatasvir, 3100-fold resistant to elbasvir, and 1.8-fold resistant to pibrentasvir. Compared with the WT, the Q24K/L28M/R30E/A92K RASs was 640,000-fold resistant to daclatasvir and ledipasvir, 150,000-fold resistant to velpatasvir, 44,000-fold resistant to elbasvir, and 1500-fold resistant to pibrentasvir. The Q24K/L28M/R30E/A92K RASs was 816.3 times more resistant to pibrentasvir than the Q24K/L28M/R30Q/A92K RASs. Furthermore, a combination of pibrentasvir and sofosbuvir showed therapeutic efficacy against these RASs. Combination regimens may eradicate HCV with NS5A Q24K/L28M/R30E/A92K RASs.

Programmed cell death-1 is involved with peripheral blood immune cell profiles in patients with hepatitis C virus antiviral therapy

Mutations in the non-structural protein regions of hepatitis C virus (HCV) are a cause of a non-sustained virological response (SVR) to treatment with direct-acting antivirals (DAAs) for chronic hepatitis; however, there are non-SVR cases without these mutations. In this study, we examined immune cell profiles in peripheral blood before and after ombitasvir/paritaprevir/ritonavir treatment and screened for genes that could be used to predict the therapeutic effects of DAAs. Fluorescence-activated cell sorting analysis indicated that the median frequencies of programmed cell death-1-positive (PD-1+) effector regulatory T cells (eTregs), PD-1+CD8+ T cells, and PD-1+Helper T cells were decreased significantly in SVR cases, but without significant changes in non-SVR cases. The frequency of PD-1+ naïve Tregs was significantly higher in the SVR group than in the non-SVR group before and after treatment. Similar results were found in patients treated with other DAAs (e.g., daclatasvir plus asunaprevir) and supported an immune response after HCV therapy. RNA-sequencing analysis indicated a significant increase in the expression of genes associated with the immune response in the SVR group, while genes related to intracellular and extracellular signal transduction were highly expressed in the non-SVR group. Therefore, we searched for genes associated with PD-1+ eTregs and CD8+ T cells that were significantly different between the SVR and non-SVR groups and found that T-box transcription factor 21 was associated with the non-SVR state. These results indicate that PD-1-related signaling pathways are associated with a non-SVR mechanism after DAAs treatment separate from mutation-related drug resistance.

Revolutionizing hepatitis C treatment: next-gen direct-acting antivirals

INTRODUCTION

With the introduction of highly effective and safe therapies with next-generation direct-acting antivirals (DAAs), that act without interferon, hepatitis C virus (HCV) infection remains the only treatable chronic infectious disease.

AREAS COVERED

The review aims to provide an overview of the therapy revolution with a description of specific DAAs, their mechanisms of action, a summary of the safety and efficacy of specific regimens, and a discussion of populations requiring special therapeutic approaches.

EXPERT OPINION

DAAs are highly effective, safe, and easy to use. However, challenges such as access to health services and loss of patients from the cascade of care, especially in groups disproportionately affected by HCV infection, such as substance abusers, make it difficult to achieve the WHO's goal of HCV elimination. The proposed strategy to combat these difficulties involves a one-step approach to diagnosing and treating the infection, the availability of long-lasting forms of medication, and the development of an effective vaccine. The aforementioned opportunities are all the more important as the world is facing an opioid epidemic that is translating into an increase in HCV prevalence. This phenomenon is of greatest concern in women of childbearing age and in those already pregnant due to treatment limitations.

Current elimination status of hepatitis C virus-infected maintenance hemodialysis patients in Iwate Prefecture, Japan

INTRODUCTION

The aim is to clarify the hepatitis C virus (HCV) status of hemodialysis (HD) patients and patient management after HCV elimination.

METHODS

Questionnaire survey was conducted in Iwate prefecture, Japan from 2016 to 2021.

RESULTS

Patients underwent HD was 2944, including 132 anti-HCV antibody-positive patients, with 91 HCV RNA-positive patients. Of the 91 HCV RNA-positive patients, 51 received antiviral treatment. Sustained virological response (SVR) rate was 94%. The patients treated with direct antiviral agents had significantly lower mortality rate than the untreated patients, and no liver-related deaths occurred in patients who achieved SVR or in HCV RNA-negative patients. The HCV RNA-positive prevalence was finally 0.79%. Approximately 40% of the facilities had dedicated beds and dialysis-related items for patients who achieved an SVR.

CONCLUSION

To eliminate HCV in HD facilities, it is necessary to promote HCV RNA testing for anti-HCV antibody-positive patients and to provide antiviral treatment for HCV RNA-positive patients. Additionally, collaboration among hepatologists and HD specialists are essential.

Drug-induced liver injury by glecaprevir/pibrentasvir treatment for chronic hepatitis C infection: a systematic review and meta-analysis

Background: Glecaprevir/pibrentasvir (G/P; 300 mg/120 mg) is a new direct-acting antiviral (DAA) that exhibits anti-hepatitis C virus (HCV) pan-genotype (GT) activity for 8, 12, or 16 weeks. However, the U.S. Food and Drug Administration have received reports that using G/P causes moderate to severe liver impairment. In some cases, isolated hyperbilirubinemia and jaundice have been reported without concomitant evidence of increased transaminase levels or other hepatic decompensation events. Objective: This study aimed to analyze the incidence of drug-induced liver injury of G/P for chronic hepatitis C virus.Materials and methods: We searched databases from the inception of each database until March 2021. Data were pooled using a random-effects model. The Cochrane Risk of Bias Tool (RoB 2.0) and the OpenMeta [Analyst] software were performed for quality assessment and quantitative studies, respectively. The primary outcome was grade 3 level of drug-induced liver injury (DILI). Results: The nine studies included in the meta-analysis involved a total of 7,650 participants, and the overall sustained virologic response rate was above 95%. The most frequent drug-related laboratory abnormalities in DILI involved total bilirubin, alanine aminotransferase, aspartate aminotransferase, and hemoglobin, but these abnormalities were minimal. The cirrhosis-without cirrhosis incidence risk ratio (IRR) was 2.724 (95% confidence interval: 1.182-6.276) in the grade 3 hyperbilirubinemia subgroup analysis. No significant differences were found within the other subgroups, in HCV GTs, and in treatment duration.Conclusions: DILI was found to occur frequently with G/P treatment. Hyperbilirubinemia occurred most frequently, especially, in patients with cirrhosis. However, G/P is still the primary therapy of choice for CKD and end-stage renal disease (ESRD) patients due to a superior safety rate.

Outcomes of Interferon-free Treatment of Hepatitis C Virus Infection Seven Years after Approval and Problems with Drop out during and after Treatment: A Retrospective, Single-center Study

Objective This retrospective, single-center study assessed the effects of interferon (IFN)-free treatment of hepatitis C virus (HCV) infection, which has been approved for seven years; calculated the incidence of hepatocellular carcinoma (HCC) after achieving a sustained virologic response (SVR); and elucidated problems with follow-up for surveillance of post-SVR HCC, particularly the impact of the coronavirus disease 2019 (COVID-19) pandemic. Methods We summarized the SVR achievement rate of 286 HCV-infected patients who received 301 IFN-free treatments and analyzed the cumulative incidence of initial HCC and the cumulative continuation rate of follow-up after SVR in the 253 patients who achieved SVR and did not have a history of HCC. Results Among 286 patients who received IFN-free treatments, 14 dropped out, and the 272 remaining patients achieved an SVR after receiving up to third-line treatment. Post-SVR HCC occurred in 18 (7.1%) of the 253 patients without a history of HCC, with a cumulative incidence at 3 and 5 years after SVR of 6.6% and 10.0%, respectively; the incidence of cirrhosis at those time points was 18.2% and 24.6%, respectively.Of the 253 patients analyzed, 58 (22.9%) discontinued follow-up after SVR. Patients who had no experience with IFN-based therapy tended to drop out after SVR. Notably, the number of dropouts per month has increased since the start of the pandemic. Conclusion Currently, IFN-free treatment is showing great efficacy. However, the incidence of HCC after SVR should continue to be monitored. In this study, the COVID-19 pandemic did not affect treatment outcomes, but it may affect surveillance for post-SVR HCC.

Alterations in Hepatocellular Carcinoma-Specific Immune Responses Following Hepatitis C Virus Elimination by Direct-Acting Antivirals

Direct-acting antivirals (DAAs) have recently revolutionized the eradication of chronic hepatitis C virus (HCV) infection. However, the effects of DAAs on the development of hepatocellular carcinoma (HCC) remain unknown. Therefore, the present study aimed to investigate immune responses to HCC influenced by DAAs in HCV-infected patients and elucidate the underlying mechanisms. We compared immune responses to 19 different HCC-related tumor-associated antigen (TAA)-derived peptides and host immune cell profiles before and 24 weeks after a treatment with DAAs in 47 HLA-A24-positive patients. The relationships between the different immune responses and phenotypic changes in immune cells were also examined. The treatment with DAAs induced four types of immune responses to TAAs and markedly altered host immune cell profiles. Prominently, reductions in the frequencies of PD-1+CD4+ and PD-1+CD8+ T cells by DAAs were associated with enhanced immune responses to TAAs. The HCV F protein was identified as contributing to the increased frequency of PD-1+ T cells, which may be decreased after eradication by DAAs. DAAs altered the immune responses of patients to HCC by decreasing the frequency of PD-1-expressing CD4+ and CD8+ T cells.

Real‐world long‐term analysis of daclatasvir plus asunaprevir in patients with hepatitis C virus infection

Background and Aim

Methods

Results

Conclusions

Possible Alterations in Appetite-related Molecules After the Elimination of Hepatitis C Virus

BACKGROUND/AIM

Recent advances in antiviral treatment have achieved a sustained viral response (SVR) in over 95% of hepatitis C virus (HCV) infections. HCV elimination is suggested to improve several lifestyle-related factors; however, few studies have focused on dietary habit-/appetite-related factors.

PATIENTS AND METHODS

HCV-infected patients who received Daclatasvir/Asnaprevir (DCV/ASV) therapy were enrolled, and the changes in appetite-related molecules after antiviral therapy were assessed with a multiple cytokine-measuring system.

RESULTS

Among 119 HCV-infected patients who received DCV/ASV treatment, 104 (87.3%) achieved an SVR. In the SVR group, DCV/ASV treatment improved several liver-related variables at 24 weeks after the completion of therapy. In patients with an SVR, the values of glucagon-like peptide 1 (GLP-1) and leptin were significantly increased at 24 weeks after completing direct-acting antiviral therapy. However, no significant change was observed in non-SVR patients, regardless of the receipt of direct-acting antiviral treatment.

CONCLUSION

Gastrointestinal hormones related to the dietary habit and/or appetite may be influenced by HCV elimination.

Aging impairs fibrosis-4 index after sustained virologic response by direct-acting antivirals in chronic hepatitis C infection

INTRODUCTION AND OBJECTIVES

Sustained virologic response (SVR) is achieved in most cases of C-type liver disease after direct-acting antiviral (DAA) therapy. Although liver fibrosis improves, the degree of improvement is different. This study aimed to analyze the factors involved in improving liver fibrosis using the fibrosis 4 (FIB-4) index.

MATERIAL AND METHODS

Patients were monitored for >3 years after SVR. At the start of therapy (SOT), liver fibrosis was categorized as either mild (<1.45 n = 28), moderate (1.45-3.25 n = 139), or advanced (>3.25 n = 236) based on the FIB-4 index. The FIB-4 index in the advanced group decreased significantly compared to that of the other two, so we selected the advanced group as the analysis target. SOT and end of therapy (EOT) factors that contributed to the FIB-4 index ≤3.25 at 3 years after therapy were examined using a multivariate analysis.

RESULTS

Among the SOT factors, age (<72 years old), absence of liver cirrhosis (LC), alanine transferase (ALT) (≥50 U/L), platelet (PLT) (≥10.2 × 10⁴/mm³), and total bilirubin (T.Bil) (<0.8 mg/dl) were the significant factors contributing to the improvement of the FIB-4 index. Among the EOT factors, age (<72 years), PLT (≥12.0 × 10⁴/mm3), and hemoglobin (Hb) (≥12.1 g/dl) were the significant factors contributing to the improvement of FIB-4 index.

CONCLUSIONS

Factors involved in the improvement of liver fibrosis after SVR were young age, absence of LC, low T.Bil., high ALT, high PLT, and high Hb levels. The levels of T.Bil, PLT, and Hb were considered to be related to portal hypertension. Aging strongly impaired the improvement in liver fibrosis.

Low Incidence of Hepatocellular Carcinoma after Antiviral Therapy in Patients with Chronic Hepatitis C and Hemophilia

Background: Hepatocellular carcinoma (HCC) rarely develops in patients with chronic hepatitis C (CHC) who achieve sustained virological response (SVR). We assessed the incidence of HCC in CHC patients with hemophilia after treatment with pegylated interferon plus ribavirin (PegIFN/RBV) and direct-acting antivirals (DAAs). Methods: Patients (n = 202) were enrolled between March 2007 and July 2019. A total of 139 patients were treated with PegIFN/RBV (genotype 1, n = 98; genotype 2, n = 41). Sixty-three patients were treated with DAAs (genotype 1, n = 44; genotype 2, n = 19). The cumulative incidence rates of HCC were estimated using the Kaplan−Meier method and compared using the log-rank test. Results: For genotype 1, SVR was achieved in 78.6% (77/98) and 90.9% (40/44) of patients in the PegIFN/RBV and DAAs groups, respectively. For genotype 2, SVR was achieved in 95.1% (39/41) and 94.7% (18/19) of patients in the PegIFN/RBV and DAAs groups, respectively. Six HCC cases were identified. The cumulative incidence of HCC was 4.1% at 14 years in PegIFN/RBV and 1.7% at 5 years in DAAs. The 14-year cumulative incidence of HCC was 1.9% in the SVR group and 21.7% in the no-SVR group in the PegIFN/RBV group (p < 0.001). Conclusions: Treatment with PegIFN/RBV led to stable SVR and a low incidence of HCC. Although the follow-up period was short, DAAs led to more stable SVR than PegIFN/RBV and a low incidence of HCC in CHC patients with hemophilia.

Effects of Hepatitis C Virus Elimination by Direct-Acting Antiviral Agents on the Occurrence of Oral Lichen Planus and Periodontal Pathogen Load: A Preliminary Report

Objective

The association between hepatitis C virus (HCV) and oral lichen planus (OLP) is well known, but the association with periodontal disease has been reported less often. The purpose of this study was to investigate the effects of periodontal bacteria and OLP lesions before and after HCV elimination. Subjects and Methods. The subjects were four OLP patients (mean age 72.5 years) with HCV infection. Six types of periodontal bacteria (Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum) were quantified in saliva, and changes in OLP were examined before and after elimination of HCV by antiviral therapy. Biochemical blood tests also were performed.

Results

The total number of periodontal bacteria, the numbers of P. gingivalis, T. forsythia, T. denticola, and F. nucleatum, and the risk of presenting with the red-complex bacteria (P. gingivalis, T. forsythia, and T.denticola), leading to periodontal disease progression, decreased after HCV elimination. OLP disappeared in three of the four patients and decreased in the other after sustained virological responses (SVRs).

Conclusion

HCV elimination not only improved OLP lesions but also reduced the number of periodontal pathogens and the amount of red-complex periodontal pathogens.

International cooperation on health and medical care for viral hepatitis: 30 years of activities on comprehensive viral hepatitis control of the JICA group training program for developing countries

The National Hospital Organization Kumamoto Medical Center has conducted a group training course for health care workers (HCW) from developing countries on viral hepatitis and its related diseases in cooperation with the Japan International Cooperation Agency, for 30 years. In the first 10 years, the course included acquired immunodeficiency syndrome (AIDS), adult T-cell leukemia/lymphoma (ATL), and hepatitis. Following the discovery of the hepatitis C virus and the genotype of the hepatitis B virus, and development of treatments for hepatitis, viral-related cirrhosis, and cancer, the course was divided into two courses. In 2015, the hepatitis training course was renewed as the "Comprehensive Countermeasure for Virus Hepatitis", which ended its role in February 2018. Between 1998 and 2017, 175 HCW from 43 countries, including 36 participants from Egypt, participated. Between October 11 and 20, 2019, we conducted a follow-up survey of the results of the training and conducted a field visit on hepatitis control in Egypt.

Treatment progress and expansion in Japan: From interferon to direct-acting antiviral

Hepatitis C virus (HCV) was first discovered in 1989, and patients infected with HCV were initially treated with interferon (IFN) monotherapy. In the 2000s, pegylated IFN combined with ribavirin was the mainstay of therapy for infected patients, but the sustained virologic response (SVR) rate was less than 50% for patients with HCV genotype 1. To further improve the therapeutic effect, direct-acting antiviral (DAA) was developed, and combination therapy with DAA and IFN has been available since 2011. In addition, IFN-free DAA therapy became available in 2014, and SVR was achieved in more than 95% of patients with chronic hepatitis and compensated cirrhosis. Thus, in just 30 years since the discovery of HCV, we aim to eliminate HCV in almost all patients. However, there are remaining issues to be addressed. Many of the patients who achieved SVR with DAA therapy had advanced liver fibrosis, and it is necessary to verify to what extent DAA therapy improves their prognosis in terms of liver function, hepatocellular carcinoma occurrence, and mortality. Resistance-associated substitutions can cause failure of DAA therapy, and the search for an effective therapy for high-level resistant viruses such as P32 deletion is particularly important. DAA therapy was approved for use in patients with decompensated cirrhosis in Japan in 2019, which is an unmet need so far. It is also important to verify the efficacy and safety in real-world settings. The World Health Organization aims to eliminate HCV by 2030, and Japan must tackle its remaining issues to achieve this goal.

Follow-up after Direct-acting Antiviral Treatment for Chronic Hepatitis C Virus Infection: Most Patients Are Followed Appropriately

Objective Chronic hepatitis C virus (HCV) infection carries a residual risk of hepatocarcinogenesis even after viral elimination, so appropriate follow-up is necessary. The present study investigated the current hospital visits and hepatocarcinogenesis status of patients who received daclatasvir plus asunaprevir treatment (DCV+ASV) to determine whether or not appropriate follow-up was being performed. Methods We retrospectively analyzed hepatocarcinogenesis, the overall survival, and the length of hospital visits in 442 patients who applied for the medical expense subsidy system for viral hepatitis and received DCV+ASV treatment in Gunma Prefecture between October 2014 and December 2015. This also included 61 patients who had a history of hepatocellular carcinoma (HCC). Results Among 442 patients, 388 achieved a sustained viral response (SVR) by DCV+ASV therapy (87.8%), and 95.9% achieved an SVR if additional treatment was included. HCC was found in 75 cases (17.0%). A history of HCC, the FIB-4 index and the treatment effect SVR were determined to be factors affecting the incidence of HCC. Regarding the follow-up rate, 89.9% of patients continued to regularly visit the hospital after 5 years of treatment. However, patients ≤60 years old had significantly lower persistence rates than older patients. The persistence rate of hospital visits to the same institution was 67.7% over a 5-year period, which was significantly better in small and medium-sized institutions than in large, specialized institutions (71.7% vs. 63.9%, p=0.039). Conclusion Patients with direct-acting antiviral treatment generally received adequate follow-up, but younger patients had a slightly higher rate of follow-up interruption and were considered to need support.

In Vitro Model for a Drug Assessment of Cytochrome P450 Family 3 Subfamily A Member 4 Substrates Using Human Induced Pluripotent Stem Cells and Genome Editing Technology

In drug development, a system for predicting drug metabolism and drug-induced toxicity is necessary to ensure drug safety. Cytochrome P450 family 3 subfamily A member 4 (CYP3A4) is an important drug-metabolizing enzyme expressed in the liver and small intestine, and predicting CYP3A4-mediated drug metabolism and drug-induced toxicity is essential. We previously developed procedures to differentiate human induced pluripotent stem (iPS) cells into hepatocyte-like cells (HLCs) or intestinal epithelial-like cells (IECs) with a fetal phenotype as well as a highly efficient genome editing technology that could enhance the homologous recombination efficiency at any locus, including CYP3A4. By using human iPS cells and our genome editing technology, we generated CYP3A4-knockout (KO) iPS cell-derived HLCs and IECs for the evaluation of CYP3A4-mediated drug metabolism and drug-induced toxicity. CYP3A4 deficiency did not affect pluripotency and hepatic and intestinal differentiation capacities, and CYP3A4 activity was entirely eradicated by CYP3A4 KO. Off-target effects (e.g., inhibition of bile acid excretion) were hardly observed in CYP3A4-KO cells but were observed in CYP3A4 inhibitor-treated (e.g., ketoconazole) cells. To evaluate whether drug-induced hepatotoxicity and enterotoxicity could be predicted using our model, we exposed CYP3A4-KO HLCs and IECs to acetaminophen, amiodarone, desipramine, leflunomide, tacrine, and tolcapone and confirmed that these cells could predict CYP3A4-mediated toxicity. Finally, we examined whether the therapeutic effects of an anti-hepatitis C virus (HCV) drug metabolized by CYP3A4 would be predicted using our model. CYP3A4-KO HLCs were treated with asunaprevir (antiviral drug metabolized by CYP3A4) after HCV infection, and the anti-viral effect was indeed strengthened by CYP3A4 KO. Conclusion: We succeeded in generating a novel evaluation system for prediction of CYP3A4-mediated drug metabolism and drug-induced toxicity.

Lifestyles Associated with Prognosis After Eradication of Hepatitis C Virus: A Prospective Cohort Study in Japan

BACKGROUND

Hepatocellular carcinoma develops in some patients with hepatitis C virus (HCV), even after achieving sustained virological response (SVR).

AIMS

We examined factors associated with liver disease progression in a prospective cohort study of SVR patients.

METHODS

Participants were patients who had visited a hospital for clinical follow-up of chronic HCV infection in 2005 and had reached SVR as a result of subsequent antiviral treatment. Baseline information including lifestyle and dietary habits before SVR was collected in 2005 using self-administered questionnaires, and clinical information before SVR was collected from medical records in 2005. Study outcome was liver disease progression such as liver cirrhosis, hepatocellular carcinoma, and/or liver disease-related death after SVR. Proportional hazard models were employed to calculate hazard ratios (HRs) and 95% confidence intervals for each variable.

RESULTS

Of 180 SVR patients, 27 patients (15%) showed liver disease progression after SVR: 26 (14%) were diagnosed with liver cirrhosis, two (1%) with hepatocellular carcinoma, and/or one (0.6%) with liver-disease-related death. Besides older age at SVR (HR = 11.9, P < 0.01) and aspartate aminotransferase-to-platelet ratio index score ≥ 1.0 before SVR (HR = 2.63, P = 0.03), alcohol drinkers before SVR (HR = 2.82, P = 0.06) were suggested to be associated with liver disease progression after SVR, whereas higher consumption of vitamin B12 before SVR showed a decreased HR for liver disease progression (HR = 0.41, P = 0.09).

CONCLUSIONS

Alcohol drinking might be associated with liver disease progression, whereas vitamin B12 intake might have protective effects against liver disease progression after eradication of HCV. Further studies are needed to confirm these findings.

Factors influencing the failure of interferon-free therapy for chronic hepatitis C: Data from the Polish EpiTer-2 cohort study

BACKGROUND

The introduction of direct-acting antiviral drugs into clinical practice has revolutionized the treatment of chronic hepatitis C, making it highly effective and safe for patients. However, few researchers have analyzed the factors causing therapy failure in some patients.

AIM

To analyze factors influencing the failure of direct antiviral drugs in the large, multicenter EpiTer-2 cohort in a real-world setting.

METHODS

The study cohort consisted of patients with chronic hepatitis C treated at 22 Polish centers from 2016-2020. Data collected from the online EpiTer-2 database included the following: hepatitis C virus (HCV) genotype, stage of fibrosis, hematology and liver function parameters, Child-Turcotte-Pugh and Model for End-stage Liver Disease scores, prior antiviral therapy, concomitant diseases, and drugs used in relation to hepatitis B virus (HBV) and/or human immunodeficiency virus (HIV) coinfections. Adverse events observed during the treatment and follow-up period were reported. Both standard and machine learning methods were used for statistical analysis.

RESULTS

During analysis, 12614 patients with chronic hepatitis C were registered, of which 11938 (mean age: 52 years) had available sustained virologic response (SVR) data [11629 (97%) achieved SVR and 309 (3%) did not]. Most patients (78.1%) were infected with HCV genotype 1b. Liver cirrhosis was diagnosed in 2974 patients, while advanced fibrosis (F3) was diagnosed in 1717 patients. We included patients with features of hepatic failure at baseline [ascites in 142 (1.2%) and encephalopathy in 68 (0.6%) patients]. The most important host factors negatively influencing treatment efficacy were liver cirrhosis, clinical and laboratory features of liver failure, history of hepatocellular carcinoma, and higher body mass index. Among viral factors, genotype 3 and viral load also exerted an influence on treatment efficacy. Classical statistical analysis revealed that treatment ineffectiveness seemed to be influenced by the male sex, which was not confirmed by the multivariate analysis using the machine learning algorithm (random forest). Coinfection with HBV (including patients with on-treatment reactivation of HBV infection) or HIV, extrahepatic manifestations, and renal failure did not significantly affect the treatment efficacy.

CONCLUSION

In patients with advanced liver disease, individualized therapy (testing for resistance-associated variants and response-guided treatment) should be considered to maximize the chance of achieving SVR.

Recent advances in the treatment of hepatitis C virus infection for special populations and remaining problems

Hepatitis C virus (HCV) infection is one of the primary causes of liver cirrhosis, hepatocellular carcinoma (HCC), and liver transplantation (LT). The rate of HCV infection is high in patients on hemodialysis and in patients infected with human immunodeficiency virus (HIV). In liver transplant patients with HCV infection, recurrent HCV infection of the transplanted liver is universal and results in rapid liver fibrosis progression. In patients with HCV/HIV coinfection as well, liver fibrosis advances rapidly. Thus, there is an urgent need for prompt HCV infection treatment in these special populations (i.e. HIV/HCV coinfection, HCV infection after LT, and dialysis patients). Interferon (IFN)-based therapy for HCV infection could not achieve a high rate of sustained viral response and could cause severe adverse events in the aforementioned special populations. Direct-acting antivirals (DAAs) have recently been developed, and clinical trials have shown that IFN-free DAA-based therapies are associated with a significantly better safety and therapeutic profile than IFN-based therapies. However, the majority of the initial DAA trials excluded special populations; thus, the efficacy and safety of IFN-free DAA-based therapy in special populations remained to be clearly established. Although recent clinical trials and clinical studies have shown the high efficacy and safety of this therapy even in special populations, several unresolved problems, including emergence of resistance-associated variants after failure to respond to DAAs and HCC occurrence after DAA therapy, still exist. Hence, in this review, we discuss the recent advances in anti-HCV therapy for special populations and the remaining problems regarding this therapy.

Change in hepatitis C virus positivity among needle-stick injury source patients: a 10-year experience in a Japanese tertiary hospital

Background

As a blood-borne pathogen, hepatitis C virus (HCV) has long been a major threat associated with needle-stick injuries (NSIs) mainly because no vaccine is available for HCV. Following an NSI, we usually test the source patient for HCV antibody (HCV-Ab). Since HCV-Ab positivity does not necessarily indicate current infection, HCV RNA is further examined in patients positive for HCV-Ab. Direct-acting antivirals (DAAs) have enabled us to treat most HCV-infected patients; therefore, we speculate that the rate of HCV RNA positivity among HCV-Ab-positive patients decreased after the emergence of DAAs. This cross-sectional study was performed to investigate the change in the actual HCV RNA positivity rate in source patients before and after the interferon (IFN)-free DAA era.

Methods

This was a cross-sectional study of NSI source patients at a tertiary academic hospital in Japan from 2009 to 2019. IFN-free DAA regimens were first introduced in Japan in 2014. Accordingly, we compared HCV status of NSI source patients that occurred between 2009 and 2014 (the era before IFN-free DAAs) with those that occurred between 2015 and 2019 (the era of IFN-free DAAs) in a tertiary care hospital in Japan.

Results

In total, 1435 NSIs occurred, and 150 HCV-Ab-positive patients were analyzed. The proportion of HCV RNA-positive patients significantly changed from 2009 through 2019 (p = 0.005, Cochran–Armitage test). Between 2009 and 2014, 102 source patients were HCV-Ab-positive, 78 of whom were also positive for HCV RNA (76.5%; 95%CI, 67.4–83.6%). Between 2015 and 2019, 48 patients were HCV-Ab-positive, 23 of whom were also positive for HCV RNA (47.9%; 95%CI, 34.5–61.7%; p = 0.0007 compared with 2009–2014). In the era of IFN-free DAAs, 9 of 23 HCV RNA-negative patients (39.1%) and 2 of 22 HCV RNA-positive patients (9.1%) were treated with an IFN-free combination of DAAs (p = 0.0351). Regarding the departments where NSIs occurred, HCV RNA-negative patients were predominant in departments not related to liver diseases in the era of IFN-free DAAs (p = 0.0078, compared with 2009–2014).

Conclusions

Actual HCV RNA positivity in source patients of NSIs decreased after the emergence of IFN-free DAAs. IFN-free DAAs might have contributed to this reduction, and HCV RNA-negative patients were predominant in departments not related to liver diseases in the era of IFN-free DAAs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06117-4.

Characteristics of patients aged over 75 years with hepatitis C virus infection treated with direct-acting antivirals in Japan: Evidence based on the nationwide, real-world database in Japan

AIM

Direct-acting antivirals (DAAs) have dramatically changed the treatment of chronic hepatitis C. Their high efficacy helps in eradicating hepatitis C virus with few adverse events. Information on real-world use of DAAs therapy in patients aged 75 years and older is inadequate.

METHODS

The Japanese DAAs database was constructed in 2014 as a cooperative system between 18 prefectures. The medical reports filled in by doctors and anonymized at the local government office were collected. The patients' demographic features, viral factors, and treatment characteristics were compared among three groups stratified by age when therapy was initiated: Group A (<60 years old), Group B (60-74 years old), and Group C (≥75 years old).

RESULTS

Out of the 22,454 patients whose age upon starting therapy could be identified, 24.8% (n = 5597) belonged to Group C, which was ten times the number in the Japanese Interferon Database. Female patients, advanced stages of liver fibrosis, and past history of hepatocellular carcinoma treatment were significantly higher in the older age groups (Group A < B < C), whereas sustained virologic response (SVR) rates were not different (91%-93%). In Group C, multivariate logistic regression analysis revealed that predicting factors for virologic response varied among DAAs regimens. However, the completion of DAAs therapy commonly contributed to SVR, regardless of DAAs regimen.

CONCLUSIONS

DAAs therapy is associated with high SVR rates, even in the oldest age group, and therapy should not be withheld on the basis of old age.

Identification of microRNA associated with the elimination of hepatitis C virus genotype 1b by direct-acting antiviral therapies

BACKGROUND AND AIM

Direct-acting antiviral (DAA) therapies have been proven to be highly effective for the eradication of hepatitis C virus (HCV) without resistance-associated substitutions (RASs). However, even in cases with no detected RASs, treatment sometimes fails, suggestive of the existence of some host-related factors involved in HCV eradication by DAAs. To explore such factors, we analyzed the serum microRNAs (miRNAs) of patients who received DAA treatment.

METHODS

The serum miRNA expression levels of 39 patients with chronic HCV infection without any detectable RASs, who achieved sustained virological response with asunaprevir/daclatasvir or grazoprevir/elbasvir therapy, were investigated cyclopedically, using oligonucleotide microarrays. The effects of specific miRNAs on the replication of HCV were measured in the HCV genomic replicon containing Huh-7 hepatoma cells.

RESULTS

Along with the disappearance of HCV, the expression quantiles of 16 miRNAs in the asunaprevir/daclatasvir group and 18 miRNAs in the grazoprevir/elbasvir group showed a tendency to increase or decrease. Among these molecules, adjustments for multiple testing yielded a significant differential expression at a false discovery rate of less than 5% for only one molecule, hsa-miR-762. Its expression quantile increased after HCV exclusion in all patients who had achieved sustained virological response. Quantitative polymerase chain reaction analysis validated a significant increase in the serum hsa-miR-762 after disappearance of HCV. On the contrary, hsa-miR-762 was decreased in the relapse and breakthrough of HCV in DAA failures. Transfection of hsa-miR-762 into cultured HCV-infected hepatocytes significantly decreased HCV-RNA replication.

CONCLUSION

These data suggest that hsa-miR-762 is one of the host factors participating in HCV exclusion by DAA therapy.

Baseline Hepatitis C Virus NS5A Resistance-Associated Polymorphisms in Patients With and Without Human Immunodeficiency Virus Coinfection in Mexico

Objective: We aimed to evaluate the frequency and associated factors of baseline NS5A resistance-associated substitutions (RASs) in patients coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) monoinfection with genotype 1b (GT1b) or genotype 1a (GT1a). Moreover, we performed a phylogenetic analysis to evaluate the pattern of clustering among samples of patients with RASs. Results: Fifty-five patients were infected with GT1a, of whom 44 (80%) were HIV-infected patients. RAS prevalence in GT1a was 14% (6/44) and distributed as follows: 5 (11%) harbored M28V and 1 (2%) A92T. Twenty-four patients were infected with HCV GT1b, of whom only 5 (21%) were HIV coinfected; RASs were found in 17/24 (71%) patients, as follows: Y93H+F37L+Q54H (1/24), Y93H+F37L (1/24), P58S (1/24), L31F+F37L (1/24), F37L+H/Q54H (3/24), and F37L (10/24). Only GT1b was significantly associated with RASs (adjusted odds ratio 16.37; 95% confidence interval 2.74-97.48; p = 0.002) in the multivariate analysis. A cluster of sequences from HIV/HCV GT1a patients was found; however, we did not find phylogenetic relationships among sequences with NS5A RASs. Conclusions: In our population of HCV-infected patients, the frequency of NS5A RASs at baseline was somewhat similar to the previously reported worldwide rate. HCV GT1b showed the most significant association with harboring of NS5A RASs. Of note, despite there being clusters among sequences of HIV-coinfected patients, NS5A RASs were not transmitted.

Analysis of hepatitis B and C virus infections amongst members of the Dental National Health Insurance Society in the Oita Prefecture

In Japan, ~3 million individuals are estimated to be infected with hepatitis B virus (HBV) or hepatitis C virus (HCV). The rates of hepatitis virus infection amongst dentists is higher than that amongst other healthcare workers due to increased exposure to both saliva and blood. However, an efficient method for the testing of hepatitis virus infections amongst dentists remains to be established. The aim of the present study was to examine the rate of hepatitis virus infection amongst dental healthcare workers (DHWs) by introducing a health checkup that included screening for HBV and HCV infections. A total of 1,834 members of the Dental National Health Insurance Society in the Oita Prefecture, consisting of dentists and other employees, were tested for hepatitis B surface antigen (HBsAg), antibodies to HBsAg (anti-HBs) and antibodies to HCV (anti-HCV) during routine medical checkups. Anonymized data, including the age, sex, occupation (dentist or employee), and presence of a hepatitis virus marker, was collected and analyzed. The positive rates of HBsAg, anti-HBs and anti-HCV in the study sample were 0.6, 44.1 and 0.5%, respectively; the positive rates were higher amongst dentists than the employees. Furthermore, the positive rates of HBsAg and anti-HCV increased with age and were higher in subjects aged 50-79 (1.7-2.2%). The positive rate of presence of anti-HBs was significantly higher in the dentists compared with employees (56.4 vs. 39.6%; respectively; P<0.0001). The three factors associated with anti-HB positivity were HBsAg negativity, occupation (dentist) and age (20-29 years) with adjusted odds ratios of 8.29, 2.27 and 1.59, respectively (P<0.05). These results suggest that introducing a hepatitis virus examination during routine health checkups of DHWs may prove useful in identifying infected individuals.

Factors affecting the recovery of hepatic reserve after sustained virologic response by direct-acting antiviral agents in chronic hepatitis C virus-infected patients

BACKGROUND AND AIM

Since the advent of direct-acting antiviral (DAA) therapy, the total eradication of hepatitis C virus has been achievable with the recovery of hepatic reserve after achievement of sustained virologic response (SVR). Hence, here, we examined the factors affecting the recovery of hepatic reserve.

METHODS

We followed up 403 patients (male: 164, female: 239; genotype 1: 299, genotype 2: 104; median age: 69 years) for at least 3 years after they achieved SVR to DAA therapy. Of these patients, 75 (18.6%) had a history of hepatocellular carcinoma (HCC). Biochemical tests were periodically performed, and the hepatic reserve was evaluated based on the albumin-bilirubin grade. We examined background factors such as age, biochemical test results, HCC occurrence and portosystemic shunt by computed tomography.

RESULTS

At the start of treatment, the albumin-bilirubin grades were grades 1, 2, and 3 in 241, 157, and 5 patients, respectively, and 3 years later, 117 of 162 (72%) patients with grade 2 or 3 improved to grade 1. Multivariate analysis identified the HCC occurrence after achievement of SVR (hazard ratio [HR]: 3.08, P < 0.0138), male sex (HR: 3.45, P = 0.0143), hemoglobin level of <11.5 g/dL (HR: 4.19, P = 0.0157), the presence of a portosystemic shunt (HR: 3.07, P = 0.0349), and alanine aminotransferase levels <45 U/L (HR: 2.67, P = 0.0425) as factors inhibiting improvement to grade 1. However, old age was not an inhibitory factor.

CONCLUSION

Our results demonstrate that hepatic reserve could be improved even in elderly patients over a long course of time.

A Hepatitis C Virus-Associated Decompensated Cirrhotic Patient Who Showed the Disappearance of Hepatic Encephalopathy, Ascites, and Pleural Effusion by Antiviral Therapy with Sofosbuvir/Velpatasvir

Oral direct-acting antivirals (DAAs) are the main therapy for hepatitis C virus (HCV)-associated liver disease in Japan. Moreover, many DAAs include an indication for compensated liver cirrhosis. However, patients with decompensated HCV-associated cirrhosis have hitherto not been indicated for therapy with DAAs. Recently, a new DAA, sofosbuvir/velpatasvir (SOF/VEL), was indicated for decompensated HCV-associated cirrhotic patients. Actually, it has been shown to eradicate HCV in many cases. However, it is not clear whether hepatic encephalopathy, ascites, and pleural effusion in patients with decompensated HCV-associated cirrhosis disappear by SOF/VEL treatment. Recently, we encountered a decompensated HCV-associated cirrhosis patient who showed the disappearance of hepatic encephalopathy, ascites, and pleural effusion with marked improvement of serum ammonia level, albumin level, prothrombin time, and platelet count after the eradication of HCV by the administration of SOF/VEL. Her consciousness was cloudy and it took many hours for the preparation of each meal just before SOF/VEL treatment, but after the disappearance of HCV-RNA by the therapy, her consciousness became clear and she could prepare meals in a short time. This case suggests the possibility of improvement from decompensated HCV-associated liver cirrhosis to compensated liver cirrhosis with disappearance of hepatic encephalopathy, ascites, and pleural effusion by SOF/VEL therapy.

Treatment of Hepatitis C Virus Infection with Direct-acting Antiviral Agents Elevates the Serum Small-dense Low-density Lipoprotein Cholesterol Level

Objective The low-density lipoprotein cholesterol (LDL) level is known to increase following the treatment of hepatitis C virus (HCV) infection using direct-acting antiviral agents (DAAs). This study aimed to investigate the changes in the lipid profiles, including small-dense LDL cholesterol (sdLDL), in HCV patients treated with DAAs. Patients We retrospectively assessed 67 HCV patients who achieved sustained virological response with DAA administration and were observed for more than 2 years, of whom 32 were on daclatasvir/asunaprevir, 14 were on sofosbuvir/ledipasvir, and 21 were on sofosbuvir/ribavirin. Methods We evaluated the lipid profiles, including sdLDL, every 6 months until 2 years after the start of treatment and analyzed the factors related to changes in the sdLDL level. Results The median sdLDL value at baseline was 12.8 mg/dL, which increased to 19.5 mg/dL at 6 months (p<0.001) and remained elevated at 25.4 mg/dL at 2 years later (p<0.001). The Kaplan-Meier curve indicated that patients with high values of LDL, albumin, muscle attenuation and visceral to subcutaneous adipose tissue area ratio were at increased risk for elevation of sdLDL over 35 mg/dL (log-rank test: p<0.001; p=0.008, p=0.002 and p=0.042, respectively). A multivariate analysis performed on the factors contributing to elevation of sdLDL 2 years after DAA treatment (≥35.0 mg/dL) revealed pretreatment LDL (≥91.0 mg/dL) and muscle attenuation (≥33.7 HU) as significant factors (p=0.007 and p=0.032, respectively). Conclusion SdLDL increased continuously after DAA treatment, and high LDL levels and low intramuscular fat deposition before treatment contributed to elevated sdLDL levels after treatment.

The role of dentists in controlling hepatocellular carcinoma in Japan (Review)

In Japan, the method of treatment for hepatitis is well established due to the high rates of hepatitis C. However, the identification of patients with hepatitis who do not receive appropriate treatment poses a major problem. Some patients with this disease may need to consult with a dentist due to the development of extrahepatic manifestations, such as lichen planus, in the oral cavity. Alternatively, the dentist might discover patients with untreated hepatitis C and hepatitis B during routine dental examination. In such cases, the patient should be referred to a hepatologist for further examinations and treatment. Thus, dentists are required to act as 'gatekeepers of hepatitis'. Furthermore, Japanese dentists need to increase hepatitis B vaccine coverage for infection control. By acting as a 'care coordinator of hepatitis', the dentist will be able to contribute to the eradication of liver cancer in Japan, thereby eliminating the discrimination and prejudice against patients with hepatitis. Dentists need to have a deep understanding of liver disease from the viewpoints of both nosocomial infection control and treatment of oral diseases.

Incidence and predictors for abnormal liver function during direct-acting antiviral agents in chronic hepatitis C patients

Abrupt alanine aminotransferase (ALT) elevation during direct-acting antiviral agents (DAA) treatment is an uncommon but noticeable adverse event in chronic hepatitis C (CHC) patients, which may lead to early termination of treatment. This study aims to investigate the incidence, outcome and predictors of the on-treatment ALT elevation during DAA therapy.CHC patients treated with DAA regimen in Chang Gung Memorial Hospital, Linkou branch during March 2015 to March 2019 were recruited. Prospective scheduled ALT assessment at baseline, 2nd, 4th, 8th, and 12th/24th weeks were recorded. Pretherapy host and viral factors were compared between patients with and without on-treatment ALT elevation. Multivariate logistic regression was used for independent factors for on-treatment ALT elevation.A total of 1563 CHC patients treated with grazoprevir/elbasvir, glecaprevir/pibrentasvir and sofosbuvir-based regimen were analyzed. On-treatment ALT elevation occurred in 10.9% patients while those treated with glecaprevir/pibrentasvir had the least possibility (5.4%). Only 1.4% patients had ≥grade 3 ALT elevation events. The presence of such events had no impact on sustained virological response 12 rates. Hepatitis B virus coinfection (aOR: 3.599, P < 0.001) and higher pretherapy ALT (1-5x, ≥5x upper limit of normal: aOR: 2.632, P = 0.024, aOR: 4.702, P = .011, respectively) were significant predictors for ALT elevation.On-treatment ALT elevation occurred in one-tenth CHC patients treated with preferred DAAs but had no impact on sustained virological response rate.

Decreased expression of interferon-stimulated genes in B cells of patients with chronic hepatitis C during interferon-free therapy potentially suggests the eradication of hepatitis C virus in the B cells: A cohort study

AIMS

Hepatitis C virus (HCV) infection is monitored by the host innate immunity that includes the endogenous interferon (IFN), which up-regulates IFN-stimulated genes (ISGs). HCV is both hepatotropic and lymphotropic, but HCV replication in lymphoid cells is a controversial issue. Here, we analyzed the mRNA levels of the ISGs in B cells of HCV-infected patients during antiviral therapy and investigated the effects of viral eradication.

METHODS

One hundred and eighty-one patients with chronic hepatitis C and 26 healthy volunteers were enrolled in this study. Levels of HCV RNA and mRNA of ISGs in B cells isolated from the patients were monitored before, during, and after antiviral therapy.

RESULTS

HCV RNA was detected in B cells of 133/175 (76.0%) patients who achieved sustained virologic response (SVR) before therapy was started. The positive ratio of HCV RNA in B cells was higher in patients with genotype 1 and the non-major genotype of interleukin 28B. HCV RNA in B cells of most patients disappeared 1 week after antiviral therapy was started. The baseline expression of ISG mRNA was significantly higher in the patients than in the healthy volunteers. Levels of ISG mRNA were increased and remained high throughout the IFN-based therapy. In contrast, levels of ISG mRNA in patients who achieved SVR were significantly decreased 1 week after the IFN-free therapy was started and remained low during the therapy.

CONCLUSIONS

These results suggested that IFN-free therapy potentially eradicated HCV in the B cells, leading to the down-regulation of endogenous ISGs. The level of ISG mRNA could be used as a marker for viral eradication in B cells.

The incidence of resistance-associated variants to NS5A in HCV subtypes 1a and 1b in Taiwan

Background

Resistance-associated variants (RAVs) to direct-antiviral agents (DAAs) may hamper treatment. There was a lack of data on the natural prevalence of RAVs in Taiwanese HCV-infected patients. We investigated the real-life presence of RAVs in the nonstructural 5A (NS5A) region in HCV genotype 1a and 1b in chronically infected individuals in Taiwan.

Methods

In this single-center cohort study, nested polymerase chain reaction and direct sequencing analysis was used to determine the frequency of RAVs in the HCV NS5A region in patients with HCV genotype 1a (n = 55) and 1b (n = 525).

Results

In genotype 1a strains, the incidence of RAVs was 16.4% (9/55) in the NS5A region (M28V/T, n = 6, 10.9%; Q30L, n = 1, 1.8%; Y93N/H, n = 3, 5.5%). In genotype 1b, the incidence of RAVs was 17.5% (92/525) in the NS5A region (L31I/M/V, n = 7, 1.3%; Y93 H/S, n = 87, 16.5%). Patients with RAVs had significantly higher HCV RNA levels (6.1 ± 0.7 vs 5.9 ± 0.8 log IU/mL, p = 0.001) and lower rGT levels (28.9 ± 18.9 vs. 42.9 ± 57.0 U/L, p = 0.001) compared to those without RAVs. Multivariate analysis identified HCV RNA levels (odds ratio = 1.145, 95% CI: 1.060–1.237, p = 0.001) and rGT (OR = 0.989, 95% CI: 0.978–0.999, p = 0.035) as risk factors that are associated with the presence of RAVs. Importantly, there is no association between the presence of RAVs and no SVR (3.8% in patients with RAVs, 15.9% in patients without RAVs, p = 0.32).

Conclusion

RAVs, especially M28V and Y93H in the NS5A region, were highly prevalent in patients with genotype 1a and 1b HCV, respectively, in Taiwan, and they were linked to high HCV RNA levels and low rGT levels. Before using the NS5A inhibitors, the presence of mutated HCV variants should be taken into consideration.

Real-word efficacy of sofosbuvir, velpatasvir plus ribavirin therapy for chronic hepatitis patients who failed to prior DAA therapy with NS5A-P32 deletion mutated HCV infection

The hepatitis C virus (HCV) NS5A-P32 deletion (P32del) confers potent resistance to NS5A inhibitors. Chronic hepatitis C patients in whom NS5A-P32del variants had emerged during prior direct-acting antiviral (DAA) therapy with an NS5A inhibitor show poor response to DAA retreatment. Here, we report three patients with HCV NS5A-P32del infection who were treated with sofosbuvir, velpatasvir plus ribavirin (SOF/VEL + RBV) in a real-world setting. The patients developed HCV NS5A-P32del, L31F + P32del, or L31V + P32del variants following failure of daclatasvir plus asunaprevir (DCV/ASV) therapy. One of the patients failed to respond to subsequent DCV/ASV and beclabuvir therapy, and the remaining two patients failed to respond to subsequent glecaprevir and pibrentasvir therapy. All three patients completed 24-week SOF/VEL + RBV therapy. Serum HCV RNA became negative at the end of the therapy in all three patients. Two patients with NS5A-P32del and NS5A-L31F + P32del achieved sustained virological response 12 weeks after completion of treatment (SVR12), but HCV relapsed in the remaining NS5A-L13V + P32del patient. Direct sequence analysis detected no additional variants within either the NS5A or NS5B regions at the time of relapse. In conclusion, three patients with prior NS5A-P32del-associated DAA treatment failure received 24 weeks of SOF/VEL + RBV therapy, and two of the patients achieved SVR12.

Pre-existing minor variants with NS5A L31M/V-Y93H double substitution are closely linked to virologic failure with asunaprevir plus daclatasvir treatment for genotype 1b hepatitis C virus infection

Background

L31 and Y93 in the NS5A region of the hepatitis C virus (HCV) are the most important substitution positions associated with resistance to direct-acting antiviral (DAA) treatment.

Methods

We analyzed the frequency of NS5A L31M/V and Y93/H in NS5A inhibitor-naive HCV genotype 1 patients who received asunaprevir plus daclatasvir combination treatment using a conventional sequencing method and a deep sequencing method that can distinguish a single substitution at either position and a double substitution at both positions with a 0.1% detection threshold.

Results

The frequency of substitutions at both sites using the conventional method was very low, with 1 in 14 non-responders and 0 in 42 randomly selected responder patients. On the other hand, for the deep sequencing method, cases with double substitutions in the tandem sequence were detected in 8/14 non-responders and 1/42 responders (p<0.0001). For the conventional method, substitutions were detected at any position in 6/14 non-responders and 2/42 responders (p = 0.0019), with a clear difference between the two groups. The difference was also clear with the deep sequencing method, with 11/14 non-responders and 8/42 responders. Interestingly, for the deep sequencing method, the single substitution of L31 was found in 6/14 non-responders and 7/42 responders, whereas single substitutions of Y93 or double substitutions were found in 7/14 vs. 1/42 and 8/14 vs. 1/42 patients, respectively.

Conclusions

NS5A L31 and Y93 substitutions were detected in tandem by the deep sequencing methods in several genotype 1 patients, who may be more resistant to DAA treatment containing an NS5A inhibitor.

In Silico Evaluation of the Effectivity of Approved Protease Inhibitors against the Main Protease of the Novel SARS-CoV-2 Virus

The coronavirus disease, COVID-19, caused by the novel coronavirus SARS-CoV-2, which first emerged in Wuhan, China and was made known to the World in December 2019 turned into a pandemic causing more than 126,124 deaths worldwide up to April 16th, 2020. It has 79.5% sequence identity with SARS-CoV-1 and the same strategy for host cell invasion through the ACE-2 surface protein. Since the development of novel drugs is a long-lasting process, researchers look for effective substances among drugs already approved or developed for other purposes. The 3D structure of the SARS-CoV-2 main protease was compared with the 3D structures of seven proteases, which are drug targets, and docking analysis to the SARS-CoV-2 protease structure of thirty four approved and on-trial protease inhibitors was performed. Increased 3D structural similarity between the SARS-CoV-2 main protease, the HCV protease and α-thrombin was found. According to docking analysis the most promising results were found for HCV protease, DPP-4, α-thrombin and coagulation Factor Xa known inhibitors, with several of them exhibiting estimated free binding energy lower than −8.00 kcal/mol and better prediction results than reference compounds. Since some of the compounds are well-tolerated drugs, the promising in silico results may warrant further evaluation for viral anticipation. DPP-4 inhibitors with anti-viral action may be more useful for infected patients with diabetes, while anti-coagulant treatment is proposed in severe SARS-CoV-2 induced pneumonia.

Regulatory T Cell Function Modulated After Successful Direct-Acting Antiviral Treatment for Chronic Hepatitis C Patients

BACKGROUNDS

Regulatory T cells (Tregs) affect the pathogenesis of chronic hepatitis C (CHC) infection.

AIMS

This study evaluated the function of Tregs in CHC patients receiving the standard direct-acting antiviral agents (DAA) treatment.

METHODS

CHC patients (n = 20) who received DAA treatment, clinical data, and function of Tregs were checked at baseline, Week 4, end of treatment (EOT), and 12 weeks after EOT (SVR 12). Treg-mediated inhibition was measured. The cytokine expression and fold change of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-10, and transforming growth factor (TGF)-β with/without Treg inhibition were also detected.

RESULTS

The cohort included 14 females with a mean age of 59.8 ± 11.5 years. Nineteen had HCV genotype 1. The HCV RNA level was 6.17 ± 0.70 log IU/mL. All patients reached the sustained virologic response. The frequency of CD4⁺Foxp3⁺T cells decreased from baseline to EOT and returned at SVR 12. The inhibitory function of Tregs decreased during treatment and then restored (baseline vs. EOT, P = 0.0393; EOT vs. SVR 12, P = 0.0052). The cytokine expression and fold change of IFN-γ and TNF-α were highest at EOT and then decreased at SVR 12. The fold change of IL-10 was lowest at EOT and then increased at SVR 12. The fold change of TGF-β was significantly increased at Week 4 and SVR 12 compared to baseline.

CONCLUSIONS

The frequency and inhibitory function of Tregs declined gradually from baseline to EOT and then increased from EOT to SVR 12 in CHC patients receiving DAA therapy. The expression of IFN-γ, TNF-α, IL-10, and TGF-β parallelled Treg function.

Clinical outcomes of hepatitis C virus elimination using glecaprevir and pibrentasvir in hemodialysis patients: A multicenter study

AIM

The incidence of hepatitis C virus (HCV) infection is much higher in hemodialysis patients than that in healthy individuals. The prognosis of hemodialysis patients with HCV infection is poorer than that without HCV infection. Therefore, antiviral intervention is pivotal for HCV infection in hemodialysis patients. Recent evaluations of the pangenotypic regimen of glecaprevir/pibrentasvir show that it is highly effective and safe for HCV-infected hemodialysis patients. However, a few reports showed that the effect of HCV elimination by glecaprevir/pibrentasvir improved liver dysfunction or anemia. The aim of the present study was to determine clinical outcomes after HCV elimination using the glecaprevir/pibrentasvir regimen in HCV-infected hemodialysis patients.

METHODS

This study was a retrospective, six-center study conducted in Japan, in which 24 hemodialysis patients with HCV genotype 1-2 treated with glecaprevir/pibrentasvir were recruited. Blood examinations were performed at end of treatment (EOT), and at 3, 6, and 12 months post-treatment during the 12-month follow-up period.

RESULTS

The overall sustained virologic response rate was 100% (24/24). During the DAA treatment period, adverse events were observed in 20.8% of patients (5/24), and pruritus was the most frequently observed in 12.5% (3/24). Interestingly, we observed an improved control of anemia after EOT with a significant increase in hemoglobin levels. In addition, total bilirubin was diminished, and platelet counts and albumin, total cholesterol, and alpha-fetoprotein levels remained unchanged after EOT in hemodialysis patients. Furthermore, erythropoietin concentration was not increased after EOT.

CONCLUSIONS

HCV elimination using glecaprevir/pibrentasvir treatment might be a major breakthrough for the control of anemia in hemodialysis patients.

Estimating the cost-effectiveness of screening for hepatitis C virus infection in Japan

AIM

The management of hepatitis C virus (HCV) has changed with the advent of interferon (IFN)-free treatment and the declining prevalence of HCV infection, which may impact the cost-effectiveness of the screening. We aimed to compare the cost-effectiveness and clinical outcomes of three screening strategies in the Japanese general population: no screening, screening plus IFN-based therapy, and screening plus IFN-free therapy.

METHODS

We developed a decision analytic Markov model for screening intervention and natural history of HCV. Model parameters were derived from published literature. A lifetime horizon and the healthcare payer perspective were taken. Subanalyses included high screening scenario with improved rates of screening and attending referral, in addition to heterogeneity analysis by age subgroup.

RESULTS

In the base case, the incremental cost-effectiveness ratio in the Japanese general population aged 40-89 years was ¥1 124 482 and ¥1 085 183 per quality-adjusted life year gained for screening plus IFN-free therapy compared with no screening and screening plus IFN-based therapy, respectively. Screening plus IFN-free therapy remained cost-effective below ¥5 000 000 per quality-adjusted life year gained in sensitivity analyses. Incremental cost-effectiveness ratios were lower in the younger population. Nearly 0.2% of HCV-related deaths were avoided by 1.5% of the general population screened followed by IFN-free therapy relative to no screening; the impact was greater with improved rates of screening and attending referral.

CONCLUSIONS

Screening and subsequent IFN-free therapy for HCV appears to be cost-effective. Early diagnosis and treatment would produce a favorable incremental cost-effectiveness ratio. Improved rates of screening and attending referral would result in further reduction of disease progression.

Recommendations from primary care physicians, family, friends and work colleagues influence patients' decisions related to hepatitis screening, medical examinations and antiviral treatment

Identification and screening of patients with hepatitis B virus (HBV) or hepatitis C virus (HCV) is important to prevent liver cancer. Comprehensive antiviral treatments should follow three sequential steps: Hepatitis screening (step 1; examination of HB surface antigen and HCV antibody), medical examination (step 2; examination of HBV-DNA and/or HCV-RNA and performance of abdominal ultrasonography) and antiviral treatment (step 3). Patients who underwent these three steps were studied to determine effective information sources (factors) for raising awareness of comprehensive treatments. A total of 182 patients from 11 medical institutions were who were undergoing antiviral treatment were investigated. The number of patients who accessed each of the 18 information sources in each of the three steps and the percentage of these information sources that directly influenced the participants to make treatment-related decisions were calculated. 'Recommendation from a primary care physician' was the most common information source (64.3, 77.5, and 75.8% at steps 1, 2, and 3, respectively). 'Recommendation from a public health nurse (PHN),' 'recommendation from friends or family,' and 'recommendation from work colleagues' were the next most common human factors (3.3-19.8%). 'Recommendation from a primary care physician' had the greatest influence (76.9, 73.0, and 77.5% at steps 1, 2, and 3, respectively). 'Recommendation from a PHN' (50.0, 26.3 and 64.3%), 'recommendations from friends and family' (58.3, 38.9 and 58.3%), and 'recommendations from work colleagues' (33.3, 33.3 and 42.9%) were highly influential factors. Media such as TV commercial messages and programs also had high recognition, but were not directly influential. The findings of the present study indicated that recommendations from primary care physicians, friends, family and work colleagues influenced patients' decision-making regarding hepatitis screening, examination and treatment.

Involvement of portosystemic shunts in impaired improvement of liver function after direct-acting antiviral therapies in cirrhotic patients with hepatitis C virus

AIM

Factors responsible for impaired improvement of liver function despite sustained viral response after direct-acting antiviral agents therapies in cirrhotic patients with hepatitis C virus need to be elucidated.

METHODS

Liver function and the extent of portosystemic shunting were evaluated for 79 patients with compensated cirrhosis, in whom sustained viral response had been achieved after direct-acting antiviral agents therapies for hepatitis C virus at least 3 years earlier.

RESULTS

Portosystemic shunts were observed in 63 patients (80%). Improvement and worsening, as compared with the baseline, of esophageal/gastric varices after direct-acting antiviral agents therapies was seen in three patients (4%) and 10 patients (13%), respectively. Portal hypertension-related events, such as varices and ascites requiring treatment, were observed in six patients (8%), in whom three patients showing worsening of Child-Pugh scores were included. Multivariate analysis showed that maximal diameter of the shunts (P = 0.012) and serum Mac-2 binding protein glycosylation isomer levels at the end of treatment (P = 0.005) were associated with the development of portal hypertension-related events, with cut-off values of 5.25 mm (P = 0.001) and 6.84 cut-off index (P < 0.001), respectively. The increase of serum albumin levels at 3 years, as compared with the baseline, was smaller in 22 patients having shunts with maximal diameters of ≥5 mm than in the remaining 57 patients (P = 0.034), whereas no such difference was seen between the patients with and without elevation of serum Mac-2 binding protein glycosylation isomer level of ≥6.8 cut-off index.

CONCLUSIONS

A large size of portosystemic shunts was found to be a crucial determinant of impaired improvement of liver function, as well as of the development of portal hypertension-related events, even after sustained viral response in patients with compensated cirrhosis.

Viral and host factors are associated with retreatment failure in hepatitis C patients receiving all-oral direct antiviral therapy

AIM

Direct-acting antiviral (DAA) therapy for hepatitis C virus is associated with high sustained virologic response rates. However, patients for whom DAA therapy fails acquire resistance-associated substitutions (RASs). We therefore evaluated the efficacy of DAA retreatment and factors associated with retreatment failure.

METHODS

Non-structural 5A RASs were investigated at the start of DAA therapy and at treatment failure in 64 patients with hepatitis C virus genotype 1b for whom DAA combination therapy had failed. A total of 59 patients were introduced to DAA retreatment. The factors associated with retreatment failure were investigated.

RESULTS

A total of 20 of 43 (46.5%) daclatasvir + asunaprevir-treated patients with virologic failure had no RASs at baseline, and three (15%) acquired P32 deletion RASs. Four of seven sofosbuvir/ledipasvir-treated patients with virologic failure had more than two RASs of NS5A at baseline. The sustained virologic response rates on retreatment were as follows: sofosbuvir/ledipasvir, 81.8%; with elbasvir + grazoprevir, 0%; and glecaprevir/pibrentasvir, 87.5%. Patients for whom sofosbuvir/ledipasvir or elbasvir + grazoprevir failed achieved sustained virologic response with glecaprevir/pibrentasvir. Two of three patients for whom glecaprevir/pibrentasvir retreatment failed had Q24/L28/R30 and A92K RASs; the other had P32 deletion RAS at baseline. Interestingly, 10 of 11 patients with retreatment failure had the interleukin (IL)-28B single-nucleotide polymorphism (SNP) minor allele. A multivariate analysis showed that the IL28B SNP minor allele (P = 0.005, odds ratio 28.291) was an independent risk factor for retreatment failure.

CONCLUSIONS

In addition to viral factors (e.g. Q24, L28, R30, and A92 or P32 deletion RASs), host factors (e.g. IL28B SNP) are associated with DAA retreatment failure.

Healthcare Expenditures for the Treatment of Patients Infected with Hepatitis C Virus in Japan

AIM

The recently developed direct-acting antivirals (DAAs) for hepatitis C virus (HCV) infections are costly. Cost-effectiveness analyses of DAAs require accurate healthcare expenditure estimates for the various HCV disease states, but few studies have produced such estimates using national-level data. This study utilized nationally representative data to estimate the healthcare expenditure for each HCV disease state.

METHODS

We identified all patients infected with HCV between April 2010 and March 2018 from a nationwide administrative claims database in Japan. Monthly patient-level healthcare expenditures were calculated for the following disease states: chronic hepatitis C (CHC), compensated cirrhosis (CC), decompensated cirrhosis (DC), and hepatocellular carcinoma (HCC). The expenditures for the CHC and CC states were also compared before DAA treatment and after sustained virologic response (SVR) was achieved. A longitudinal two-part model was employed to estimate the healthcare expenditures for each state.

RESULTS

During the study period, 1,564,043 patients with 146,488,137 patient-months of data met the inclusion criteria. The year of valuation was 2017. The mean monthly healthcare expenditures per patient (95% confidence intervals) for the pre-DAA CHC, CC, DC, and HCC states were US$267 (US$267-268), US$428 (US$427-429), US$666 (US$663-669), and US$969 (US$966-972), respectively. The mean monthly healthcare expenditures per patient for the post-SVR (≥ 2 years) CHC and CC states were US$176 (US$176-177) and US$238 (US$236-240), respectively. Healthcare expenditure increased with increasing age in all disease states (P < 0.05).

CONCLUSIONS

These healthcare expenditure estimates from a nationally representative sample have potential applications in cost-effectiveness analyses of DAAs.

Favorable outcome of retreatment by direct-acting antivirals for hepatitis C patients with daclatasvir plus asunaprevir combination therapy failure

AIM

In patients with hepatitis C virus, treatment failure of daclatasvir plus asunaprevir combination therapy (DCV + ASV) seems to become intractable due to the induction of resistance-associated substitutions. This study aimed to investigate the outcomes of retreatment with direct-acting antivirals (DAAs) in patients with DCV + ASV therapy failure, as well as changes in drug resistance mutations.

METHODS

We retrospectively analyzed 44 patients re-treated with DAAs after DCV + ASV failure between December 2015 and April 2018. All patients were analyzed for amino acid substitutions, and additional treatment regimens were selected based on the results and current treatment guidelines.

RESULTS

The sustained virological response rate with second-line treatment was 81.8% (36/44), and relapse occurred in five of 16 patients who received sofosbuvir/ledipasvir and three of seven patients who received DCV/ASV/beclabuvir. Third- and fourth-line treatments were also tried in relapsed cases, and the overall sustained virological response rates were 90.9% (40/44) and 93.2% (41/44), respectively. A high rate of viral clearance was eventually observed. Before second-line treatment, the prevalence of mutations in the NS5A and NS3/4A regions was 100% (44/44) and 86.4% (38/44), respectively. There was no significant increase in the number of amino acid substitutions in patients for whom second-line treatment failed.

CONCLUSIONS

Amino acid substitutions were frequently observed in patients with DCV + ASV failure, but most patients achieved a sustained virological response after retreatment with DAAs. Although the spread of drug-resistant viruses due to unsuccessful DAA treatment was a matter of concern, most cases of DCV + ASV failure were overcome with additional treatment.

Single-molecular real-time deep sequencing reveals the dynamics of multi-drug resistant haplotypes and structural variations in the hepatitis C virus genome

While direct-acting antivirals (DAAs) for hepatitis C virus (HCV) have dramatically progressed, patients still suffer from treatment failures. For the radical eradication of HCV, a deeper understanding of multiple resistance-associated substitutions (RASs) at the single-clone level is essential. To understand HCV quasispecies and their dynamics during DAA treatment, we applied single-molecule real-time (SMRT) deep sequencing on sera from 12 patients with genotype-1b HCV infections with DAA treatment failures, both pre- and post-treatment. We identified >3.2 kbp sequences between NS3 and NS5A genes of 187,539 clones in total, classifying into haplotype codes based on the linkage of seven RAS loci. The number of haplotype codes during the treatment, per sample, significantly decreased from 14.67 ± 9.12 to 6.58 ± 7.1, while the number of nonsynonymous codons on the seven RAS loci, per clone, significantly increased from 1.50 ± 0.92 to 3.64 ± 0.75. In five cases, the minority multi-drug resistant haplotypes at pre-treatment were identical to the major haplotypes at relapse. Moreover, various structural variations (SVs) were detected and their dynamics analysed. These results suggest that SMRT deep sequencing is useful for detecting minority haplotypes and SVs, and to evaluate the dynamics of viral genomes at the single-clone level.

Intention-to-treat assessment of glecaprevir + pibrentasvir combination therapy for patients with chronic hepatitis C in the real world

AIMS

We assessed the problems and efficacy of glecaprevir + pibrentasvir (GLE/PIB) therapy for patients infected with hepatitis C virus (HCV) in the real world.

METHOD

A total of 423 patients infected with HCV who started treatment at eight different centers in Japan were enrolled in the study. Glecaprevir (300 mg) and pibrentasvir (120 mg) were given once daily for 8 weeks to 246 non-cirrhotic direct-acting antiviral (DAA)-naive patients with HCV genotype (GT)-1 or -2, and for 12 weeks to patients who: were DAA-naive cirrhotic (n = 55), had experienced DAA failure (n = 78), were cirrhotic and had DAA failure (n = 37), and were other GT-1/2 (n = 7). Anti-HCV efficacy was defined as a sustained virologic response 12 weeks post-treatment (SVR12). The evaluation was undertaken in an intention-to-treat (ITT) population and in patients who were assessed at SVR12 (modified ITT population).

RESULTS

In the ITT population, 220 (89%) patients on the 8-week regimen and 164 (93%) patients on the 12-week regimen achieved SVR12. The 30 dropout patients were predominantly men and with GT-2. All other DAA-naive GT-1 patients achieved SVR12. The 12-week regimen resulted in 100% SVR12 in 41 GT-2 patients. Nine patients did not achieve SVR12: two DAA naive with GT-2a, two GT-3b patients, two GT-1 patients with discontinuation, and three other GT-1 patients with a history of DAA failure. Four of seven patients who discontinued treatment due to severe adverse effects were more than 75 years old.

CONCLUSIONS

Glecaprevir + pibrentasvir had a remarkable anti-HCV effect in GT-1 and GT-2 patients, but not in GT-3b patients. Although this therapy was reasonably safe, it is necessary to carefully consider elderly and dropout patients.

Effects of resistance-associated variants in genotype 2 hepatitis C virus on viral replication and susceptibility to antihepatitis C virus drugs

AIMS

Development of direct-acting antivirals (DAAs) has made antihepatitis C virus (HCV) treatment highly safe and effective. However, the emergence of resistant-associated variants (RAVs) after failure of DAA therapy affects retreatment outcomes. In particular, genotype 1 HCV with P32 deletion has been reported to be highly resistant to all approved non-structural protein (NS)5A inhibitors. However, analysis of RAVs in genotype 2 HCV has been limited. Accordingly, in this study, we evaluated the roles of genotype 2 HCV variants in antiviral drug efficacy.

METHODS

We utilized HCV-2b/2a (JFH-1) chimeric virus (genotype 2a), which replicates more robustly than JFH-1. We constructed various genotype 2a JFH-1-based HCV cell culture systems with NS3 (D168E), NS5A (F28S, F28S/M31I, P32 deletion, and Y93H), and NS5B (S282 T) RAVs and analyzed the replication ability and sensitivity to various anti-HCV reagents.

RESULTS

Genotype 2a-based HCV with NS5A-P32 deletion could not replicate even in long-term cultures. Genotype 2a-based HCV with NS5A-F28S/M31I showed significantly higher replication ability than the wild-type strain, and replication could not be suppressed, even with high concentrations of NS5A inhibitors, including pibrentasvir and velpatasvir (<1000-10 000 fold-resistance compared with the wild-type strain). However, genotype 2a-based HCV with NA5A-F28S/M31I was sensitive to HCV protease inhibitor, NS5B inhibitor, interferon-α, and ribavirin. Genotype 2a-based HCV with NS5B-S282 T was resistant to sofosbuvir, but was highly sensitive to ribavirin compared with the control.

CONCLUSIONS

When undertaking retreatment for genotype 2a HCV-infected patients who fail to respond to DAAs, the optimized retreatment should be chosen according to the sensitivity of the emerging RAVs to anti-HCV drugs.