Rapid, Sensitive, and Accurate Evaluation of Drug Resistant Mutant (NS5A-Y93H) Strain Frequency in Genotype 1b HCV by Invader Assay

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.

Real-world efficacy of elbasvir and grazoprevir for hepatitis C virus (genotype 1): A nationwide, multicenter study by the Japanese Red Cross Hospital Liver Study Group

AIM

The present study aimed to determine the real-world efficacy and safety of the non-structural protein (NS)5A inhibitor elbasvir (EBR) combined with the NS3/4A protease inhibitor grazoprevir (GZR) in patients with hepatitis C virus (HCV) genotype 1 (GT1) infection.

METHODS

This study retrospectively evaluated the rate of sustained virologic response at 12 weeks post-treatment (SVR12) and the safety of EBR/GZR treatment in 159 men and 194 women with a median age of 72 years, and it assessed factors associated with the SVR12 rate. The attending physicians were responsible for selecting candidate patients for EBR/GZR in this retrospective study.

RESULTS

Treatment outcomes for EBR/GZR were good in direct-acting antiviral (DAA)-naïve patients, of whom 99.4% achieved SVR. Of 353 patients, 10 (2.9%) had treatment failure. Of these patients, eight previously underwent DAA therapy, and the remaining two had NS5A-L31/Y93 double mutation. The SVR rate was 50% (8/16 patients) in patients who previously underwent DAA therapy, and 18.2% (2/11 patients) in patients with NS5A-L31/Y93 double mutation. On multivariate logistic regression analysis, NS5A-Y31/Y93 double mutation (odds ratio 356.3; 95% confidence interval, 23.91-16 940; P < 0.0001) was identified as an independent predictor of treatment failure. No serious adverse events were observed with EBR/GZR therapy.

CONCLUSIONS

The SVR rate of EBR/GZR would have been 100% in patients without either a history of DAA therapy or double mutation. This combination of drugs could be safely given and is, thus, considered a highly useful first-line treatment for DAA-naïve patients with HCV.

Exploring the hepatitis C virus genome using single molecule real-time sequencing

Single molecular real-time (SMRT) sequencing, also called third-generation sequencing, is a novel sequencing technique capable of generating extremely long contiguous sequence reads. While conventional short-read sequencing cannot evaluate the linkage of nucleotide substitutions distant from one another, SMRT sequencing can directly demonstrate linkage of nucleotide changes over a span of more than 20 kbp, and thus can be applied to directly examine the haplotypes of viruses or bacteria whose genome structures are changing in real time. In addition, an error correction method (circular consensus sequencing) has been established and repeated sequencing of a single-molecule DNA template can result in extremely high accuracy. The advantages of long read sequencing enable accurate determination of the haplotypes of individual viral clones. SMRT sequencing has been applied in various studies of viral genomes including determination of the full-length contiguous genome sequence of hepatitis C virus (HCV), targeted deep sequencing of the HCV NS5A gene, and assessment of heterogeneity among viral populations. Recently, the emergence of multi-drug resistant HCV viruses has become a significant clinical issue and has been also demonstrated using SMRT sequencing. In this review, we introduce the novel third-generation PacBio RSII/Sequel systems, compare them with conventional next-generation sequencers, and summarize previous studies in which SMRT sequencing technology has been applied for HCV genome analysis. We also refer to another long-read sequencing platform, nanopore sequencing technology, and discuss the advantages, limitations and future perspectives in using these third-generation sequencers for HCV genome analysis.

Real-world efficacy and safety of ledipasvir and sofosbuvir in patients with hepatitis C virus genotype 1 infection: a nationwide multicenter study by the Japanese Red Cross Liver Study Group

BACKGROUND

We aimed to describe the real-world efficacy and safety of combination therapy with ledipasvir and sofosbuvir (LDV/SOF) for chronic hepatitis C virus (HCV) genotype 1 (GT1) infection.

METHODS

This retrospective analysis of a prospective, nationwide, multicenter registry included GT1-infected patients treated with LDV/SOF for 12 weeks. We assessed the rate of sustained virological response at 12 weeks post-treatment (SVR12), incidence of adverse events, and serum markers of hepatocellular carcinoma (HCC).

RESULTS

Among the 1461 patients included (mean age, 69 years; 29.5% aged > 75 years; cirrhosis, 23.8%; history of treatment for HCC, 10.9%), the overall SVR12 rate was 98.4% (1438/1461). Factors associated with treatment failure were cirrhosis (odds ratio, 4.19; p = 0.014) and resistance-associated substitutions (RASs) in NS5A at baseline (odds ratio, 7.78; p = 0.0004). The SVR12 rate in patients with cirrhosis and NS5A RASs was 93.0% compared to 100% in patients without cirrhosis or NS5A RASs. In patients with SVR, the levels of alpha-fetoprotein (AFP), AFP-L3, and Mac-2 binding protein glycosylation isomer (M2BPGi) decreased from baseline to end of treatment (from 13.4 ± 37.6 to 6.0 ± 10.6 ng/mL, p < 0.0001; from 2.2 ± 4.9 to 1.5 ± 6.3%, p < 0.005; and from 3.6 ± 3.7 to 2.0 ± 3.5 cut-off index, p < 0.0001; respectively). Adverse events were rare and not associated with age. No decrease in estimated glomerular filtration rate was observed in patients with baseline chronic kidney disease stage 3.

CONCLUSIONS

LDV/SOF therapy is highly effective and safe in elderly Japanese patients with HCV GT1, even in the presence of cirrhosis or NS5A RASs. Patients with SVR may have a lower risk of HCC.

Advanced liver fibrosis effects on the response to sofosbuvir-based antiviral therapies for chronic hepatitis C

BACKGROUND

Sustained virological response (SVR) rates for the treatment of chronic hepatitis C virus (HCV)-infected patients have drastically improved with the use of direct-acting antiviral (DAA) therapies; however, a small minority of patients still fails to eradicate the virus. We analyzed factors associated with SVR in DAA therapy and the effect of age and liver fibrosis on treatment response.

METHODS

Nine hundred and eighteen patients with chronic HCV infection were treated with 24 weeks of daclatasvir plus asunaprevir (DCV + ASV) or 12 weeks of sofosbuvir plus ledipasvir (SOF + LDV), ombitasvir, paritaprevir plus ritonavir (OMB + PTV + r) or sofosbuvir plus ribavirin (SOF + RBV). Multivariate logistic regression analysis was used to identify factors associated with SVR. The effect of age and liver fibrosis on SVR was analyzed.

RESULTS

The overall SVR rate was 95.4% (876 of 918 patients), and rates by DAA regimen were 93.4%, 95.7%, 100%, and 95.0% in DCV + ASV-treated, SOF + LDV-treated, OMB + PTV + r-treated, and SOF + RBV-treated patients, respectively. Patients older than 75 years achieved a similar SVR rate with those aged 75 years or younger (96.4% and 94.8%, respectively). Multivariate logistic regression analysis identified absence of DAA therapy history (odds ratio [OR], 3.868 for presence; P = 0.002) and FIB-4 index of less than 3.25 (OR, 5.042 for ≥3.25; P = 0.001) as independent predictors for SVR. SVR rates were significantly lower in patients with FIB4 index of 3.25 or more compared with those with less than 3.25, especially in sofosbuvir-based therapies such as SOF + LDV-treated or SOF + RBV-treated patients.

CONCLUSION

Both older and younger patients respond similarly to DAA therapy. Advanced liver fibrosis affects the virological response to sofosbuvir-based therapy.

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

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

Significance of NS5B Substitutions in Genotype 1b Hepatitis C Virus Evaluated by Bioinformatics Analysis

To evaluate the effects of HCV NS5B amino acid substitutions on treatment outcome in Ledipasvir (LDV)/Sofosbuvir (SOF) for Japanese patients with genotype 1b HCV infection, NS5B sequences were examined in i) seven patients experiencing virologic failure after LDV/SOF in real-world practice, ii) 109 SOF-naïve patients, iii) 165 patients enrolled in Phase-3 LDV/SOF trial. A218S and C316N were detected in all patients with viral relapse; the percentages of these substitutions in SOF-naïve patients were 64.2% and 55.0%, respectively. Genotype 1b HCV strains with NS5B-C316N mutation were located in the leaves different from those in which HCV strains without such substitutions were present on the phylogenetic tree. Structural modeling revealed that amino acid 218 was located on the surface of the NTP tunnel. Free energy analysis based on molecular dynamics simulations demonstrated that the free energy required to pass through the tunnel was larger for triphosphate SOF than for UTP in NS5B polymerase carrying A218S, but not in wild-type. However, no susceptibility change was observed for these substitutions to SOF in replicon assay. Furthermore, the SVR rate was 100% in patients enrolled the Phase-3 trial. In conclusion, NS5B A218S and C316N were detected in all patients who relapsed following LDV/SOF in real-world practice. These substitutions did not impact the overall SVR rate after LDV/SOF, however, further studies are needed to elucidate the impact of these substitutions.

Differences in the Serum 4β-hydroxycholesterol Levels of Patients with Chronic Hepatitis C Virus (HCV) Infection: A Possible Impact on the Efficacy and Safety of Interferon (IFN)-free Treatment

Objective Since the majority of direct-acting antivirals (DAAs) that are used in the treatment of hepatitis C virus (HCV) infection are mainly metabolized by CYP3A4, it is hypothesized that inter-individual differences in CYP3A4 activity may be associated with the bioavailability of these agents. Methods The level of serum 4β-hydroxycholesterol (4βHC), a surrogate marker of CYP3A4 activity, was determined by LC-MS/MS in samples obtained from patients with HCV infection (CHCs) as well as healthy control subjects (CTLs). Serum samples obtained from patients treated with either asunaprevir/daclatasvir (ASV/DCV) or ombitasvir/paritaprevir/ritonavir (OTV/PTV/r) were used for additional assays. Results The serum 4βHC level in CHCs was significantly higher than that in CTLs, and a gender difference was seen among CHCs. In patients treated with OTV/PTV/r, the serum 4βHC level was observed to gradually decrease during the treatment period. In the cohort treated with ASV/DCV, 4 of 83 patients showed virological treatment failure. In pretreatment testing, an Invader assay detected a low prevalence of resistance-associated variants in these four patients. The average serum concentration of DCV/ASV in the treatment-failed group tended to be lower than that in the sustained virological response (SVR) group. The pretreatment serum 4βHC level in patients with treatment failure was significantly higher than that in patients with an SVR but in whom the prevalence of resistance-associated variants was low in the pretreatment setting. Conclusion The evaluation of CYP3A4 activity by measuring 4βHC before treatment may provide additional information that can potentially be used to select cost- and efficacy-optimized treatment of HCV.

Retreatment with sofosbuvir/ledipasvir with or without lead-in interferon-β injections in patients infected with genotype 1b hepatitis C virus after unsuccessful daclatasvir/asunaprevir therapy

AIM

To improve the therapeutic efficacy of sofosbuvir/ledipasvir (SOF/LDV) for the retreatment of patients after daclatasvir/asunaprevir (DCV/ASV), a customized therapy with or without lead-in interferon (IFN)-β injections was formulated according to the types of resistance-associated substitutions (RAS) in the non-structural protein (NS)5A region of genotype 1b hepatitis C virus (HCV).

METHODS

Thirty-three patients failing prior DCV/ASV received SOF/LDV for 12 weeks. Patients with HCV carrying unfavorable NS5A-RAS and/or those previously treated with simeprevir were given lead-in IFN-β injections twice a day for 2 weeks; sequential changes in the NS5A-RAS during the injection period were evaluated using deep sequencing.

RESULTS

Lead-in injections were not undertaken in 27 patients; a sustained viral response (SVR) was achieved in 26 patients, while viral relapse occurred in 1 patient with HCV carrying NS5A-L28M/R30H/Y93H mutations. Among the 6 patients receiving lead-in injections, viral relapse occurred in 2 patients who had an unfavorable IFN-λ3-related gene single nucleotide polymorphism allele; both patients had been previously treated with simeprevir, and HCV carrying NS5A-L31V/Y93H mutations had emerged after DCV/ASV. Deep sequencing revealed no changes in the NS5A-RAS profiles during the lead-in injection period in either patient. In contrast, in a patient with a favorable allele who was infected with similar unfavorable HCV strains, NS5A-L31/Y93 wild-type strains appeared during the injection period, enabling an SVR.

CONCLUSION

Using customized therapies based on the NS5A-RAS profiles, a high SVR rate was obtained after SOF/LDV in patients failing prior DCV/ASV. Lead-in IFN-β injections did not improve the efficacy in patients with HCV carrying unfavorable NS5A-RAS except in those with a favorable IFN-λ3-related gene allele.

The efficacy and safety of dual oral therapy with daclatasvir and asunaprevir for genotype 1b in Japanese real-life settings

BACKGROUND & AIMS

It is important to investigate the treatment outcomes in patients excluded from clinical trials (CTR). The aims of this study were to evaluate the efficacy and safety of a 24-week daclatasvir (DCV) and asunaprevir (ASV) therapy for patients with chronic hepatitis C virus (HCV)-1b infection.

METHODS

A total of 651 HCV-1b patients started dual oral therapy with DCV and ASV for 24 weeks in Toranomon Hospital, Tokyo. Among them, 276 patients met phase III CTR inclusion criteria. The sustained virological response (SVR) rate after treatment and the adverse events during therapy were compared between CTR-met (patients who met the inclusion criteria) and CTR-unmet (patients who did not meet the inclusion criteria) groups.

RESULTS

SVR12 was achieved in 87.0% (240/276) and 86.7% (325/375) in CTR-met and CTR-unmet patients respectively. SVR12 rate in simeprevir-experienced patients was 52.9% (9/17). SVR12 rate in patients without resistance-associated variant (RAV) of NS3 or NS5A loci was 93.7% (416/444). However, the SVR12 rates in patients with NS3-D168, NS5A-L31 and Y93 single RAV at baseline were 55.0% (11/20), 73.9% (17/23) and 65.6% (63/96) respectively. The safety profiles in both CTR-met and CTR-unmet patients were similar. The discontinuation rate as a result of alanine aminotransferase (ALT) elevation was only 2.9%. Seven (2.5%) patients in CTR-met group and 20 (5.3%) in CTR-unmet group discontinued therapy because of adverse events other than the ALT elevation.

CONCLUSIONS

Dual oral therapy with DCV and ASV in real-life settings was well tolerated with a similar safety profile and achieved similar SVR12 rates as that of CTR.

Evaluation of antiviral effect of type I, II, and III interferons on direct-acting antiviral-resistant hepatitis C virus

Treatment of hepatitis C virus (HCV) infection has greatly improved in the last 5 years because of the identification of direct-acting antivirals (DAAs). However, concerns exist regarding the emergence of drug resistance-associated substitutions (RASs). In this study, we evaluated the in vivo antiviral effect of three classes of interferons (IFNs), namely, types I, II, and III IFNs, on DAA-resistant HCVs. IFN-α₂, IFN-γ, and IFN-λ₁ were selected as typical types I, II, and III IFNs, respectively. Human hepatocyte-transplanted chimeric mice were infected with NS3-D168, NS5A-L31-, and NS5A-Y93-mutated HCVs, and the antiviral effect of IFN-α₂, IFN-γ, and IFN-λ₁ on these HCV RASs was examined. Chimeric mice infected with NS3- and NS5A-mutated HCVs were hydrodynamically injected with IFN-expressing plasmids to evaluate the antiviral effect of IFNs. Serum concentrations of IFNs were maintained for at least 42 days. We found that serum HCV level significantly decreased and serum and hepatic HCV levels reached below detection limit in 5/5 and 3/5 chimeric mice injected with IFN-γ- and IFN-λ₁-expressing plasmids, respectively. The antiviral effect of IFN-α₂ on DAA-resistant HCVs was weaker than that of IFN-γ and IFN-λ₁. Serum ALT levels showed a small and transient increase in mice injected with the IFN-γ-expressing plasmid but not in mice injected with the IFN-λ₁-expressing plasmid. However, no apparent histological damage was observed in the liver sections of mice injected with the IFN-γ-expressing plasmid. These results indicate that IFN-γ and IFN-λ₁ are an attractive therapeutic option for treating infection caused by NS3- and NS5A-mutated HCV.

Emergence of drug resistance-associated variants and changes in serum lipid profiles in sofosbuvir plus ledipasvir-treated chronic hepatitis C patients

Combination of sofosbuvir plus ledipasvir therapy has been expected to enhance sustained virological response (SVR) rates in hepatitis C virus (HCV) genotype 1 chronic infected patients. We analyzed the emergence of drug resistance-associated variants (RAVs) in treatment failure and changes in lipid profiles in sofosbuvir/ledipasvir-treated patients. A total of 176 patients with chronic HCV genotype 1 infection without decompensated liver cirrhosis were treated with sofosbuvir/ledipasvir for 12 weeks. NS5A and NS5B RAVs were determined by either Invader assay or direct sequencing. Serum lipid-related markers were measured at the start of treatment and at week 4 in patients who received sofosbuvir/ledipasvir and ombitasvir/paritaprevir/ritonavir therapies. SVR was achieved in 94.9% (167 out of 176) of patients. SVR12 rate was 97.1% for patietns with low frequncy (<25%) of baseline NS5A RAVs, but 82.8% for patients with high frequency (>75%) of NS5A RAVs. In multivariate regression analysis, higher albumin (odds ratio [OR] = 0.020 for presence; P = 0.007), and NS5A-L31/Y93 RAVs with a population frequency <75% (OR = 29.860 for presence; P = 0.023) were identified as significant independent predictors for SVR12. NS5A-Y93H substitutions were detected in all nine treatment failures at HCV relapse, and three out of six patients with NS5A inhibitor-naïve patients achieved additional NS5A RAVs. Serum low-density lipoprotein cholesterol and apolipoprotein B levels were significantly elevated at week 4 in sofosbuvir/ledipasvir-treated patients. These elevations were greater than in ombitasvir/paritaprevir/ritonavir-treated patients. In conclusion, NS5A multi-RAVs are likely to develop in patients who fail to respond to sofosbuvir/ledipasvir therapy. Inhibition of HCV replication with sofosbuvir might affect lipid metabolism.

New resistance-associated substitutions and failure of dual oral therapy with daclatasvir and asunaprevir

BACKGROUND

Daclatasvir (DCV) and asunaprevir (ASV) combination therapy has been primarily used in patients without NS5A L31 or Y93 resistance-associated substitutions (RASs) before treatment. We examined the characteristics of patients without these baseline RASs who did not achieve hepatitis C virus eradication with DCV and ASV combination therapy and identified new baseline NS5A RASs that are closely associated with failure of combination therapy.

METHODS

Three hundred thirty-five patients with hepatitis C virus genotype 1 infection with no NS5A L31, NS5A Y93, and NS3 D168 RASs before DCV and ASV combination therapy and no history of protease inhibitor therapy were enrolled. All RASs were evaluated by direct sequencing.

RESULTS

Sustained virologic response at 12 weeks (SVR12) was achieved in 297 patients (89%). Patients with NS5A Q24, L28, and/or R30 RASs or concomitant NS5A F37 and Q54 RASs had a significantly lower SVR12 rate than patients without these RASs (70% vs 92%, p < 0.001 and 79% vs 92%, p = 0.002 respectively). Multivariate analysis showed that NS5A Q24, L28, and/or R30 RASs and concomitant NS5A F37 and Q54 RASs were significantly associated with virologic failure. The SVR12 rate in patients without NS5A Q24, L28, and/or R30 RASs and concomitant NS5A F37 and Q54 RASs was 96.2% (202/210).

CONCLUSIONS

In patients without NS5A L31 or Y93 RASs, the presence of NS5A Q24, L28, and/or R30 RASs and concomitant NS5A F37 and Q54 RASs at the baseline was associated with failure of DCV and ASV combination therapy. The coexistence of baseline RASs other than NS5A L31 and Y93 may affect the therapeutic effectiveness of DCV and ASV combination therapy.

Safety and efficacy of dual therapy with daclatasvir and asunaprevir for older patients with chronic hepatitis C

BACKGROUND

Daclatasvir and asunaprevir combination therapy has shown a high virological response for chronic genotype 1 hepatitis C virus (HCV)-infected patients. However, the safety and efficacy of the therapy for older patients are unknown.

METHODS

One hundred seventy patients younger than 75 years and 139 patients aged 75 years or older with genotype 1 HCV infection were treated for 24 weeks with daclatasvir plus asunaprevir. Pretreatment drug-resistance-associated variants at NS5A-L31 and NS5A-Y93 were determined by the Invader assay. Virological response and adverse events according to age were analyzed.

RESULTS

The sustained virological response (SVR) rate for older patients was similar to that for younger patients (97.1 and 92.4 % respectively). In multivariate regression analysis, prior simeprevir treatment (odds ratio 56.6 for absence; P < 0.001) was identified as a significant independent predictor of SVR. The SVR rate for patients with pretreatment resistance-associated variants (RAVs) at a low population frequency (less than 25 %) was similar to that for patients with no detectable RAVs. The frequency of adverse events was similar between younger and older patients. All 19 very elderly patients (85 years or older) completed the 24 weeks of treatment and achieved SVR.

CONCLUSIONS

Older patients have a virological response and tolerance of daclatasvir plus asunaprevir therapy similar to those of younger patients. Even though RAVs were detected, virological response similar to that for patients with no detectable RAVs may still be expected for patients with RAVs as long as the population frequency is low.

Efficacy and safety of daclatasvir plus asunaprevir therapy for chronic hepatitis C patients with renal dysfunction

Chronic hepatitis C virus (HCV) infection is associated with renal dysfunction. Daclatasvir and asunaprevir combination therapy showed a high virological response for genotype 1 chronic HCV-infected patients with renal dysfunction on hemodialysis. However, the safety and efficacy of the therapy for patients with renal dysfunction who are not on hemodialysis are not well-known. In total, 147 patients with chronic HCV genotype 1 infection were treated with 24 weeks of daclatasvir plus asunaprevir therapy. Among these patients, 126 had normal renal function (estimated glomerular filtration rate [eGFR] ≥ 50 ml/min/1.73 m² ) and 21 had renal dysfunction (eGFR < 50 ml/min/1.73 m² ). Plasma concentrations of daclatasvir and asunaprevir after 5 days of treatment were the same in the normal renal function and renal dysfunction groups. Early virological response (4, 8, 48, 96, and 168 hr after the start of the therapy) was similar between the two groups. End-of-treatment response was achieved in 122 (96.8%) and 20 (95.2%) patients with normal renal function and with renal dysfunction, respectively, and sustained virological response was achieved in 119 (94.4%) and 20 (95.2%) patients. The frequency of adverse events was also comparable between the two groups. Treatment discontinuation due to adverse events was required for only one patient in each group. Renal function did not change either during or after treatment in both groups. In conclusion, renal function is unlikely to have a significant impact on blood kinetics of daclatasvir and asunaprevir. This combination therapy was effective and safe for patients without hemodialysis. J. Med. Virol. 89:665-671, 2017. © 2016 Wiley Periodicals, Inc.

Real-world efficacy and safety of daclatasvir and asunaprevir therapy for hepatitis C virus-infected cirrhosis patients

BACKGROUND AND AIMS

Daclatasvir and asunaprevir combination therapy has shown a high virological response for chronic genotype 1 hepatitis C virus (HCV) infected-patients. However, the real-world efficacy and safety of the therapy for patients with cirrhosis are unknown.

METHODS

A total of 252 patients with genotype 1 HCV infection (158 with chronic hepatitis and 94 with compensated liver cirrhosis) were treated with 24 weeks of daclatasvir and asunaprevir combination therapy. Plasma concentrations of daclatasvir and asunaprevir at day 5 of treatment, end-of-treatment response, sustained virological response (SVR), and the frequencies of adverse events were analyzed.

RESULT

Plasma asunaprevir concentration was significantly higher, and daclatasvir concentration tended to be higher, in cirrhosis patients compared with chronic hepatitis patients. End-of-treatment response was achieved in 95.6% and 94.7% of chronic hepatitis and cirrhosis patients, respectively, and SVR was achieved in 94.3% and 92.6%. Although pre-treatment NS5A drug resistant-associated variants were detected, a high SVR rate was achieved when the population frequency of the variant was low. The frequencies of treatment-related adverse events in cirrhosis patients were similar to those in chronic hepatitis patients. Treatment discontinuation due to adverse events occurred in three and two patients in chronic hepatitis and cirrhosis groups, respectively; however, four out of five patients with treatment discontinuation nonetheless achieved SVR.

CONCLUSION

Patients with compensated liver cirrhosis have similar virological response and tolerance for daclatasvir plus asunaprevir therapy to patients with chronic hepatitis. This combination therapy might offer a safe and effective treatment for chronic HCV infected-patients with compensated cirrhosis.

Three patients treated with sofosbuvir plus ledipasvir for recurrent hepatitis C after liver transplantation

We previously reported results of interferon (IFN)-free daclatasvir and asunaprevir for the treatment of recurrent hepatitis C virus (HCV) genotype 1 infection after liver transplantation (LT). Here we report three patients who achieved viral response with no effect on the blood concentrations of immunosuppressive agents following sofosbuvir plus ledipasvir treatment. The first patient was a 68-year-old female with HCV-related liver cirrhosis who failed to respond to pegylated-IFN and ribavirin (PEG-IFN/RBV) after living donor LT. She had been treated with 50 mg/day of cyclosporine. The second was a 63-year-old male with HCV-related liver cirrhosis and hepatocellular carcinoma who failed to respond to PEG-IFN/RBV after living donor LT. He had been treated with 50 mg/day of cyclosporine. The third was a 63-year-old female with HCV-related liver cirrhosis. She had been treated with tacrolimus. High alanine aminotransferase levels persisted after LT. Liver biopsy examination revealed active hepatitis or chronic rejection. Therefore, sofosbuvir plus ledipasvir therapy was started. However, the combination treatment was stopped at 4 weeks due to development of interstitial pneumonia. Serum HCV RNA became negative at the time treatment was discontinued and remained negative 12 weeks after cessation of therapy in all three cases. Sofosbuvir plus ledipasvir treatment showed a remarkable viral response with little effect on blood levels of immunosuppressive agents for recurrent HCV genotype 1 infection after LT.

Cost-effectiveness of direct-acting antiviral regimen ombitasvir/paritaprevir/ritonavir in treatment-naïve and treatment-experienced patients infected with chronic hepatitis C virus genotype 1b in Japan

OBJECTIVE

This study compared the cost-effectiveness of chronic hepatitis C virus (HCV) genotype 1b (GT1b) therapy ombitasvir/paritaprevir/ritonavir (OBV/PTV/r) vs daclatasvir + asunaprevir (DCV/ASV) and no treatment in patients without cirrhosis. Cost-effectiveness analyses (CEAs) that compared OBV/PTV/r against DCV/ASV and sofosbuvir/ledipasvir (SOF/LDV) in Y93H mutation-negative, GT1b patients with and without cirrhosis were also included.

METHODS

A health state transition model was developed to capture the natural history of HCV. A CEA over a lifetime horizon was performed from the perspective of the public healthcare payer in Japan. Costs, health utilities, and rates of disease progression were derived from published studies. Sustained virologic response (SVR) rates of OBV/PTV/r and DCV/ASV were extracted from Japanese clinical trials. Analyses were performed for treatment-naïve and -experienced patients. Alternative scenarios and input parameter uncertainty on the results were tested.

RESULTS

OBV/PTV/r exhibited superior clinical outcomes vs comparators. For OBV/PTV/r, DCV/ASV, and no treatment, the lifetime risk of decompensated cirrhosis in treatment-naïve patients without cirrhosis was 0.4%, 1.4%, and 9.2%, and hepatocellular carcinoma was 6.5%, 11.4%, and 49.9%, respectively. Quality-adjusted life years (QALYs) were higher in treatment-naïve and -experienced patients without cirrhosis treated with OBV/PTV/r (16.41 and 16.22) vs DCV/ASV (15.83 and 15.66) or no treatment (11.34 and 11.23). In treatment-naïve and -experienced patients without cirrhosis, the incremental cost-effectiveness ratios (ICERs) of OBV/PTV/r vs DCV/ASV were JPY 1,684,751/QALY and JPY 1,836,596/QALY, respectively; OBV/PTV/r was dominant compared with no treatment. In scenario analysis, including GT1b patients with and without cirrhosis who were Y93H mutation-negative, the ICER of OBV/PTV/r vs DCV/ASV was below the Japanese willingness-to-pay threshold of JPY 5 million/QALY, while the ICER of SOF/LDV vs OBV/PTV/r was above this threshold; thus, OBV/PTV/r was cost-effective.

CONCLUSION

OBV/PTV/r appears to be a cost-effective treatment for chronic HCV GT1b infection against DCV/ASV. OBV/PTV/r dominates no treatment in patients without cirrhosis.

A Comprehensive Computational Analysis for the Binding Modes of Hepatitis C Virus NS5A Inhibitors: The Question of Symmetry

Direct-acting antivirals (DAAs) form the current standard of care (SOC) against hepatitis C virus (HCV). These drugs selectively target the viral proteins, offering a unique mechanism to avoid toxicity, to increase their efficacy, and to evolve from decades of interferon- and ribavirin-based therapy. Among the promising HCV targets for DAAs is the NS5A protein, and daclatasvir (DCV) forms a first-in-class compound that selectively targets this protein. Despite the exceptional potency of DCV (∼picomolar IC₅₀) and although several DCV derivatives have been approved for human use or are close to approval, the exact mode of action of these drugs is still incomplete. This is simply due to the vast complexity of cocrystallizing DCV with NS5A in the absence of two amphipathic helices that are required for DCV binding. In this context, computational modeling provides a unique alternative to solve this problem. Here, we build upon our recent discovery of a completely symmetrical interaction between DCV and NS5A and investigate the mode of binding of six other structures similar to DCV. The selected compounds include both symmetric and asymmetric molecules. In addition, we show that our model correlates very well with mutations that can confer resistance to DCV. The current study enhances our understanding of the mode of action of this class of HCV inhibitors and helps in defining the origin of resistance to these drugs.

Impact of resistance-associated variant dominancy on treatment in patients with HCV genotype 1b receiving daclatasvir/asunaprevir

Sustained virological responses (SVR) by daclatasvir (DCV) and asunaprevir (ASV) therapy for genotype 1b hepatitis C virus (HCV) infected patients has been significantly affected by pre-existence of Y93 H resistance-associated variants (RAVs) in the non-structural protein 5A (NS5A) region. The aim of this study was to elucidate the dominancy of naturally occurring RAVs in viral quasispecies on treatment outcomes in patients with HCV. In total, 138 patients were prospectively selected from 152 patients treated with DCV and ASV, where evaluation of treatment outcomes at 12 weeks post-treatment was possible. Pre-treatment RAVs in the non-structural protein 3 and NS5A regions were detected by polymerase chain reaction (PCR)-Invader assays, and the ratio of Y93H RAVs in viral quasispecies was measured by quantitative PCR-Invader assay. Among 25 patients detected the Y93H RAV, the Y93H ratio was 1-25% in 5 patients, 26-75% in 7 patients, and ≥76% in 13 patients. Overall, SVR at 12 weeks after the completion of treatment (SVR12) was 91% (125/138), and those with Y93H ratios of <1%, 1-25%, 26-75%, and ≥76% were 99%, 100%, 71%, and 23%, respectively. Thus, the SVR12 decreased as the HCV Y93H ratio increased (P < 0.0001). The dominancy of pre-treatment RAVs of DCV and ASV affected its treatment outcomes, suggesting that evaluating the dominancy of HCV RAVs could be required for every other direct-acting antiviral agent treatments. J. Med. Virol. 89:99-105, 2017. © 2016 Wiley Periodicals, Inc.

Impact of Pre-existing NS5A-L31 or -Y93H Minor Variants on Response Rates in Patients Infected with HCV Genotype-1b Treated with Daclatasvir/Asunaprevir

INTRODUCTION

The combination of daclatasvir (DCV, pan-genotypic NS5A inhibitor) plus asunaprevir (ASV; NS3 protease inhibitor) is approved in Japan, Korea and other countries for the treatment of chronic hepatitis C virus (HCV) genotype (GT)-1. A high (~90 to 100%) sustained virologic response (SVR) with DCV/ASV therapy has been achieved by excluding patients infected with HCV GT-1b with baseline NS5A resistance-associated variants (RAVs) at L31 or Y93H detected by direct sequencing (DS). We set out to determine whether patients with minor variants at NS5A-L31 or -Y93H, detected by next-generation sequencing (NGS), impacted SVR rates with DCV/ASV therapy.

METHODS

Baseline samples from 222 interferon (IFN)-ineligible/intolerant (N = 135) and prior non-responder (N = 87) patients infected with GT-1b who were treated with DCV/ASV for 24 weeks in the Phase 3 clinical study AI447026 were prepared for NGS (Ion-Torrent platform). The prevalence of baseline NS5A RAVs and their impact on SVR when observed at ≥1% by NGS in a patient's virus population were examined. NGS and DS (sensitivity ≥20%) data were compared.

RESULTS

The prevalence of baseline NS5A RAVs at L31 or Y93H was 29% (63/219) and 18% (39/214) by NGS and DS, respectively. SVR24 rates were comparable in patients without observed baseline L31 or Y93H polymorphisms whether assessed by NGS (96%; 148/154) or by the less sensitive DS platform (95%; 164/173).

CONCLUSION

Optimal SVR rates (≥95%) to DCV/ASV treatment were achieved using DS to exclude patients infected with GT-1b with NS5A RAVs at L31 or Y93H representing ≥20% of their virus population. Exclusion by NGS of patients with minor variants in NS5A (<20%) did not enhance SVR rates. These results suggest that the presence of minor variants in NS5A does not appear to impact the overall SVR rate in patients with GT-1b treated with DCV/ASV.

FUNDING

This study was sponsored by Bristol-Myers Squibb.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01497834.

Three patients treated with daclatasvir and asunaprevir for recurrent hepatitis C after liver transplantation: Case report

We previously reported our data on telaprevir or simeprevir used in combination with pegylated interferon (PEG IFN) and ribavirin (RBV) for the treatment of recurrent hepatitis C virus (HCV) genotype 1 infection after liver transplantation (LT). Here, we report three patients who achieved viral responses with no effect on the blood concentrations of immunosuppressive agents following daclatasvir and asunaprevir treatment. The first patient was a 57-year-old man with HCV-related liver cirrhosis who failed to respond to PEG IFN/RBV after living donor LT. He had been treated with 1 mg/day of tacrolimus. The second was a 63-year-old man with HCV-related liver cirrhosis and hepatocellular carcinoma who failed to respond to PEG IFN/RBV after living donor LT. He had been treated with 1 mg/day of tacrolimus. The third was a 61-year-old man with HCV-related liver cirrhosis. He had been treated with mycophenolate mofetil (MMF). Serum HCV RNA became undetectable by TaqMan polymerase chain reaction test after 4 weeks of daclatasvir and asunaprevir treatment in all patients, and no remarkable fluctuations in blood concentration were observed either in tacrolimus or in MMF during 24 weeks of therapy. No adverse events were observed, and all patients received the full dose of daclatasvir and asunaprevir over 24 weeks. Serum HCV RNA remained negative at 12 weeks after the end of treatment in all patients. The daclatasvir and asunaprevir treatment showed a remarkable viral response with little effect on blood levels of immunosuppressive agents for recurrent HCV genotype 1 infection after LT.

Daclatasvir plus Asunaprevir Treatment for Real-World HCV Genotype 1-Infected Patients in Japan

Background. All-oral combination of direct-acting antivirals could lead to higher sustained virologic response (SVR) in hepatitis C virus (HCV)-infected patients. In the present study, we examined the efficacy and safety of the dual oral treatment with HCV nonstructural protein (NS) 5A inhibitor daclatasvir (DCV) plus HCV NS3/4A inhibitor asunaprevir (ASV) for 24 weeks in real-world HCV genotype 1-infected Japanese individuals. Methods. After screening for HCV NS5A resistance-associated variants (RAVs) by PCR invader assay, a total of 54 Japanese patients infected with HCV genotype 1 treated with DCV plus ASV were retrospectively analyzed. SVR12 was used for evaluation of the virologic response. Results. Of the total 54 patients, 46 patients (85.2%) were treated with DCV plus ASV for 24 weeks and achieved SVR12. The other 8 patients (14.8%) discontinued this treatment before 24 weeks due to adverse events. Of these 8 patients, 5 and 3 patients did and did not achieve SVR12, respectively. Finally, 51 of 54 (94.4%) patients achieved SVR12. Conclusion. Treatment with DCV and ASV after screening for HCV NS5A RAVs by PCR invader assay is effective and safe in the treatment of real-world HCV genotype 1-infected patients in Japan.

Combination therapies with daclatasvir and asunaprevir on NS3-D168 mutated HCV in human hepatocyte chimeric mice

BACKGROUND

Although the frequency of emergent drug-resistant strains of HCV in patients who failed to respond to simeprevir plus pegylated interferon (PEG-IFN) and ribavirin (RBV) decreased after cessation of the treatment, it is not clear whether or not the NS3-D168 variants affect the outcome of NS5A and NS3 inhibitor combination therapy. In this study, we investigated the relationship between the effect of daclatasvir plus asunaprevir treatment and the frequencies of NS3-D168 variants.

METHODS

HCV genotype-1b-infected human hepatocyte chimeric mice with various frequencies of NS3-D168 amino acid substitutions were treated with asunaprevir alone or in combination with daclatasvir for 4 weeks. Frequencies of NS3-D168 substitutions at baseline were analysed by ultra-deep sequencing. Some mice with NS3-D168 substitutions were treated with PEG-IFN or telaprevir for 4 weeks.

RESULTS

Mice with high frequencies of NS3-D168 showed low susceptibility to asunaprevir treatment and failed to respond to daclatasvir plus asunaprevir therapy. In contrast, mice with a low frequency (less than approximately 14%) of NS3-D168 showed a similar susceptibility to wild-type HCV-infected mice and achieved viral eradication with daclatasvir plus asunaprevir therapy. Although treatment with either telaprevir or PEG-IFN resulted in reduction of serum HCV RNA levels, no significant decrease in the frequency of NS3-D168 substitutions was achieved.

CONCLUSIONS

Daclatasvir and asunaprevir treatment could eliminate NS3-D168 variant HCV if the frequency was low. It is necessary to confirm that the frequency of NS3-D168 variants has decreased sufficiently before adopting daclatasvir plus asunaprevir therapy in patients with simeprevir plus PEG-IFN/RBV treatment failure.

HCV Drug Resistance Challenges in Japan: The Role of Pre-Existing Variants and Emerging Resistant Strains in Direct Acting Antiviral Therapy

Sustained virological response (SVR) rates have increased dramatically following the approval of direct acting antiviral (DAA) therapies. While individual DAAs have a low barrier to resistance, most patients can be successfully treated using DAA combination therapy. However, DAAs are vulnerable to drug resistance, and resistance-associated variants (RAVs) may occur naturally prior to DAA therapy or may emerge following drug exposure. While most RAVs are quickly lost in the absence of DAAs, compensatory mutations may reinforce fitness. However, the presence of RAVs does not necessarily preclude successful treatment. Although developments in hepatitis C virus (HCV) therapy in Asia have largely paralleled those in the United States, Japan’s July 2014 approval of asunaprevir plus daclatasvir combination therapy as the first all-oral interferon-free therapy was not repeated in the United States. Instead, two different combination therapies were approved: sofosbuvir/ledipasvir and paritaprevir/ritonavir/ombitasvir/dasabuvir. This divergence in treatment approaches may lead to differences in resistance challenges faced by Japan and the US. However, the recent approval of sofosbuvir plus ledipasvir in Japan and the recent submissions of petitions for approval of paritaprevir/ritonavir plus ombitasvir suggest a trend towards a new consensus on emerging DAA regimens.