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

Retreatment of chronic hepatitis C virus genotype-4 patients after non-structural protein 5A inhibitors' failure: efficacy and safety of different regimens

BACKGROUND

Nonstructural protein 5A (NS5A) is an important regimen for the treatment of chronic hepatitis C virus (HCV) genotype-4 infected patients. Retreatments for NS5A virologic failure are limited. The aim of this study is to provide real-life data regarding the effectiveness and safety of retreatment with different regimens after NS5A regimen virologic failure in GT4 patients.

PATIENTS AND METHODS

A total of 524 HCV patients (mean age 48 ± 11 years, 71% males), with virologic failure to sofosbuvir+daclatasvir, n = 450 and sofosbuvir/ledipasvir, n = 74 were included in this study. Patients were retreated with sofosbuvir + ombitasvir/paritaprevir/ritonavir + ribavirin, n = 278 and sofosbuvir + simeprevir + daclatasvir + ribavirin, n = 246. Response was evaluated 12 weeks after the end of treatment (SVR12).

RESULTS

Overall, SVR12 was 95.2% [95% confidence interval (CI) 93.3%-97.1%]. In sofosbuvir + ombitasvir/paritaprevir/ritonavir + ribavirin and sofosbuvir + simeprevir + daclatasvir + ribavirin, SVR12s were 94.9% (95% CI 92.5%-97.4%) and 95.5% (95% CI 92.8%-98%), respectively. In liver cirrhosis patients, SVR12s were 96.4% (95% CI 90.7%-100%) and 98% (95% CI 94.9%-100%), respectively. Relapse in the sofosbuvir + ombitasvir/paritaprevir/ritonavir + ribavirin was n = 14 patients, and n = 11 patients in sofosbuvir + simeprevir + daclatasvir + ribavirin. Three patients developed hepatic encephalopathy, haematemesis, lower limb oedema, and one patient died in the SOF + OBV/PTV/RTV + RIB. In the sofosbuvir + simeprevir + daclatasvir + ribavirin, three patients developed hepatocellular carcinoma and one patient died. No treatment discontinuation due to anaemia.

CONCLUSION

Salvage treatment for NS5A-treatment failure is effective and well tolerated in genotype-4 patients, in both noncirrhotic and compensated cirrhotic groups.

Pooled analysis of HCV genotype 1 resistance-associated substitutions in NS5A, NS3 and NS5B pre-and post-treatment with 12 weeks of daclatasvir, asunaprevir and beclabuvir

BACKGROUND

Daclatasvir (DCV; non-structural [NS]5A inhibitor) plus asunaprevir (ASV; NS3 inhibitor) plus beclabuvir (BCV; non-nucleoside NS5B inhibitor) is an approved regimen for hepatitis C virus (HCV) genotype (GT)-1 treatment in Japan. A comprehensive analysis of pre-treatment and treatment-emergent HCV resistance to this regimen ± ribavirin (RBV) was performed.

METHODS

Data were pooled from five Phase 2/3 studies of DCV+ASV+BCV±RBV given for 12 weeks to GT-1a- or GT-1b-infected patients. The prevalence and impact of pre-treatment resistance-associated substitutions (RAS) in NS5A, NS3, and NS5B on sustained virological response (SVR) was assessed, as were emergent RAS and their post-treatment persistence.

RESULTS

Baseline NS5A RAS (GT-1a: M28T, Q30H/L/R/S, L31M, Y93C/H; GT-1b: L31I/M, Y93C/H) were present in 5% (26/561) of GT-1a and 16% (85/537) of GT-1b sequences. SVR12 for GT-1b without RBV was 100% (82/82) with RAS and >99% (427/428) without RAS. For GT-1a, SVR12 without RAS was 97% (85/88) with RBV and 92% (410/447) without RBV; SVR12 with RAS was 100% (2/2) with RBV and 54% (13/24) without RBV. Baseline NS3 (at R155 or D168) and NS5B (at P495) RAS were rare (≤1%). Treatment-emergent NS5A RAS (mostly Q30E/H/K/R±Y93H/N) in GT-1a persisted 60 weeks post-treatment, while NS3 RAS (mostly R155K) and NS5B-P495L/S were no longer detected after 48 or 24 weeks, respectively.

CONCLUSIONS

DCV+ASV+BCV±RBV was highly efficacious in HCV GT-1 infection, including HCV GT-1b with NS5A RAS. The fitness of treatment-emergent RAS post-treatment was NS5A > NS3 > NS5B; NS3 and NS5B RAS were generally replaced by wild-type sequence within 48 weeks.

Real-life effectiveness and safety of the daclatasvir/asunaprevir combination therapy for genotype 1b chronic hepatitis C patients: An emphasis on the pretreatment NS5A resistance-associated substitution test

This study aimed to investigate the real-life effectiveness and safety of daclatasvir (DCV) and asunaprevir (ASV) combination therapy in Korean patients. We consecutively enrolled patients with genotype 1b hepatitis C virus (HCV) infection treated with at least one dose of DCV/ASV combination therapy in seven tertiary hospitals of South Korea. The sustained virologic response (SVR) rates and safety according to intention-to-treat (ITT) and per-protocol (PP) analyses were evaluated. Among the 526 enrolled patients, 91% showed negative (87%) or "undetermined" (4%) resistance-associated substitution (RAS); 9% did not undergo RAS testing. The SVR rates for ITT and PP were 89.3% and 95.0% in treatment-naive patients and 93.2% and 95.6% in treatment-experienced patients, respectively. In PP analysis, negative RAS was associated with higher SVR (96.3%) than with "undetermined RAS" (85.7%) or "not tested for RAS" (84.4%). Adverse events were reported in 185 (35.4%) patients, and events leading to discontinuation were observed in 4.3% of the study population. Forty-two (8.0%) patients developed transaminase elevation (≥2 × upper normal limit), resulting in treatment discontinuation in six (1.1%) patients. DCV/ASV combination therapy showed acceptable efficacy in genotype 1b compensated HCV-infected patients with negative pretreatment RAS. Although most adverse events were tolerable to continue antiviral treatment, adequate monitoring for transaminase elevation is warranted.

Next-generation sequencing for the clinical management of hepatitis C virus infections: does one test fits all purposes?

While the prospect of viral cure is higher than ever for individuals infected with the hepatitis C virus (HCV) due to ground-breaking progress in antiviral treatment, success rates are still negatively influenced by HCV's high genetic variability. This genetic diversity is represented in the circulation of various genotypes and subtypes, mixed infections, recombinant forms and the presence of numerous drug resistant variants among infected individuals. Common misclassifications by commercial genotyping assays in combination with the limitations of currently used targeted population sequencing approaches have encouraged researchers to exploit alternative methods for the clinical management of HCV infections. Next-generation sequencing (NGS), a revolutionary and powerful tool with a variety of applications in clinical virology, can characterize viral diversity and depict viral dynamics in an ultra-wide and ultra-deep manner. The level of detail it provides makes it the method of choice for the diagnosis and clinical assessment of HCV infections. The sequence library provided by NGS is of a higher magnitude and sensitivity than data generated by conventional methods. Therefore, these technologies are helpful to guide clinical practice and at the same time highly valuable for epidemiological studies. The decreasing costs of NGS to determine genotypes, mixed infections, recombinant strains and drug resistant variants will soon make it feasible to employ NGS in clinical laboratories, to assist in the daily care of patients with HCV.

Efficacy and safety of 12 weeks of daclatasvir, asunaprevir plus ribavirin for HCV genotype-1b infection without NS5A resistance-associated substitutions

BACKGROUND/PURPOSE

Treatment with daclatasvir plus asunaprevir (DCV + ASV) for 24 weeks provided a sustained virologic response (SVR) rate of over 90% in hepatitis C virus genotype 1b (HCV-1b) infected patients without non-structural 5A (NS5A) resistance-associated substitutions (RASs) at the L31 and Y93 sites. In this study, we investigated whether adding ribavirin to the DCV + ASV combination could shorten the original treatment regimen to 12 weeks without compromising the treatment efficacy for HCV-1b patients without NS5A RASs.

METHODS

In the prospective, open-label, single-arm, nationwide multi-center phase III study, a total of 70 interferon-naïve or interferon-experienced HCV-1b patients without baseline L31/Y93 RASs received daclatasvir (60 mg/day) and asunaprevir (100 mg twice daily) plus weight-based ribavirin (1000-1200 mg/day) for 12 weeks, with a 12-week post-treatment follow-up. The primary end-point was the rate of undetectable HCV RNA 12 weeks post-treatment (SVR12).

RESULTS

The SVR12 rate was 97.1% (68/70) and 100% (68/68) in the full-analysis-set and the per-protocol population, respectively. None of the 68 patients who completed the 12-week treatment experienced relapse during post-treatment follow-up. Two patients withdrew from the study at treatment days 21 and 34 due to anorexia and fatigue, which were considered ribavirin-related and resolved post medication cessation. A total of 4 serious adverse events were reported and considered treatment-unrelated. No deaths or grade 4 adverse events requiring hospitalization was observed throughout the study.

CONCLUSION

Truncated regimen of DCV + ASV plus ribavirin for 12 weeks was highly effective and safe in HCV-1b patients without NS5A L31/Y93 RAS.

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

Background/Aims

Although daclatasvir with asunaprevir was approved in Japan for interferon ineligible or intolerant patients, patients aged ≥75 years were excluded in the phase III trial. The present study aimed to evaluate the safety and efficacy of this therapy for elderly patients aged ≥75 years and to clarify whether an extremely high sustained virological response (SVR) rate can be achieved, even in a real-world setting when patients with resistance-associated substitutions (RASs) to nonstructural protein 5A (NS5A) inhibitors or prior simeprevir failure are excluded.

Methods

Daclatasvir (60 mg) and asunaprevir (100 mg) were orally administered daily for 24 weeks. Patients without pre-existing NS5A RASs and simeprevir failure were enrolled in this study.

Results

Overall, 110 patients were treated. The median age was 73 years old. The SVR rates of total patients, those aged ≥75 years, and those aged <75 years were 97% (107/110), 98% (46/47), and 97% (61/63), respectively. The treatment of two patients (2%) was discontinued because of adverse events.

Conclusions

Daclatasvir with asunaprevir was a safe treatment, even in patients aged ≥75 years. When patients without pre-existing NS5A RASs and prior simeprevir failure were selected, an extremely high SVR rate could be achieved irrespective of age.

Impact of hepatitis C virus polymorphisms on direct-acting antiviral treatment efficacy: Regulatory analyses and perspectives

Several highly effective, interferon-free, direct-acting antiviral (DAA)-based regimens are available for the treatment of chronic hepatitis C virus (HCV) infection. Despite impressive efficacy overall, a small proportion of patients in registrational trials experienced treatment failure, which in some cases was associated with the detection of HCV resistance-associated substitutions (RASs) at baseline. In this article, we describe methods and key findings from independent regulatory analyses investigating the impact of baseline nonstructural (NS) 3 Q80K and NS5A RASs on the efficacy of current United States Food and Drug Administration (FDA)-approved regimens for patients with HCV genotype (GT) 1 or GT3 infection. These analyses focused on clinical trials that included patients who were previously naïve to the DAA class(es) in their investigational regimen and characterized the impact of baseline RASs that were enriched in the viral population as natural or transmitted polymorphisms (i.e., not drug-selected RASs). We used a consistent approach to optimize comparability of results across different DAA regimens and patient populations, including the use of a 15% sensitivity cutoff for next-generation sequencing results and standardized lists of NS5A RASs. These analyses confirmed that detection of NS3 Q80K or NS5A baseline RASs was associated with reduced treatment efficacy for multiple DAA regimens, but their impact was often minimized with the use of an intensified treatment regimen, such as a longer treatment duration and/or addition of ribavirin. We discuss the drug resistance-related considerations that contributed to pretreatment resistance testing and treatment recommendations in drug labeling for FDA-approved DAA regimens.

CONCLUSION

Independent regulatory analyses confirmed that baseline HCV RASs can reduce the efficacy of certain DAA-based regimens in selected patient groups. However, highly effective treatment options are available for patients with or without baseline RASs. (Hepatology 2018;67:2430-2448).

The presence of multiple NS5A RASs is associated with the outcome of sofosbuvir and ledipasvir therapy in NS5A inhibitor-naïve patients with chronic HCV genotype 1b infection in a real-world cohort

It is unclear whether multiple nonstructural (NS) 5A resistance-associated substitutions (RASs) correlate with the outcome of sofosbuvir (SOF) and ledipasvir (LDV) therapy. We investigated the effects of multiple NS5A RASs in NS5A inhibitor-naïve patients with chronic hepatitis C virus genotype 1b infection treated with SOF/LDV. In 313 patients treated with SOF/LDV, we assessed the effects of multiple NS5A RASs on the sustained virological response (SVR). RASs at L28, R30, L31, Q54, P58, Q62, A92, and Y93 in the NS5A region were examined by direct sequencing. The prevalence of RASs was as follows: 2.6% at L28, 8.7% at R30, 6.1% at L31, 48.7% at Q54, 9.9% at P58, 9.9% at Q62, 5.1% at A92, 13.8% at Y93, and 19.2% at L31 or Y93. A total of 133 patients had no RASs. SVR was achieved in 98.7% of the patients. SVR rates significantly differed between patients with and without the L31 or Y93 RAS (93.0% [53/57] vs 100% [250/250], P = .0011). In addition, among patients with the L31 or Y93 RAS, 29.8%, 45.6% and 24.6% had one, two and three or more NS5A RASs, respectively. The SVR rate was significantly lower in patients with the L31 or Y93 RAS with more than three NS5A RASs compared to those with fewer than three NS5A RASs (71.4% [10/14] vs 100% [43/43], P = .0025). Although the prevalence of multiple NS5A RASs at baseline was low in NS5A inhibitor-naïve patients, the presence of multiple NS5A RASs was associated with the effectiveness of SOF/LDV therapy.

The safety and efficacy of elbasvir and grazoprevir in participants with hepatitis C virus genotype 1b infection

BACKGROUND

Genotype 1b (GT1b) is the most common subtype of the hepatitis C virus (HCV). We present an integrated analysis of 1070 participants with HCV GT1b infection from 30 countries who received elbasvir/grazoprevir for 12 weeks.

METHODS

This is a retrospective analysis of data from participants with chronic HCV GT1b infection enrolled in 11 phase II/III clinical trials. All participants received elbasvir 50 mg plus grazoprevir 100 mg once daily for 12 weeks. The primary end point of all studies was sustained virologic response 12 weeks after completion of therapy (SVR12, HCV RNA < 15 IU/ml).

RESULTS

SVR12 was 97.2% (1040/1070). Of the 30 participants who failed to attain SVR12, 15 relapsed and 15 had nonvirologic failure. Among participant subgroups, SVR12 was high in those with compensated cirrhosis (188/189, 99.5%), HIV co-infection (51/54, 94.4%), and baseline viral load > 800,000 IU/ml (705/728, 96.8%). Resistance-associated substitutions (RASs) at NS5A positions 28, 30, 31, or 93 were present in 21.6% of participants at baseline. SVR12 was 99.6% (820/823) in participants without baseline NS5A RASs and 94.7% (215/227) in those with baseline NS5A RASs. Serious adverse events occurred in 3.2% (34/1070) of participants, nine of which occurred after study medication was completed.

CONCLUSIONS

Elbasvir/grazoprevir for 12 weeks represents an effective treatment option for participants with HCV GT1b infection. SVR12 was high in all participant subgroups, including those with compensated cirrhosis, HIV co-infection, and high baseline viral load. CLINICALTRIALS.

GOV IDENTIFIERS

The trials discussed in this paper were registered with Clinicaltrial.gov as the following: NCT02092350 (C-SURFER), NCT02105662 (C-EDGE Co-Infection), NCT02105467 (C-EDGE treatment-naive), NCT02105701 (C-EDGE treatment-experienced), NCT01717326 (C-WORTHy), NCT02251990 (C-CORAL), NCT02105688 (C-EDGE COSTAR), NCT02252016 (C-EDGE IBLD), NCT02115321 (C-SALT), NCT02203149 (Japan phase 2/3 study), NCT02358044 (C-EDGE Head-2-Head).

Daclatasvir plus asunaprevir in treatment-naïve patients with hepatitis C virus genotype 1b infection

AIM

To assess daclatasvir plus asunaprevir (DUAL) in treatment-naïve patients from mainland China, Russia and South Korea with hepatitis C virus (HCV) genotype 1b infection.

METHODS

Patients were randomly assigned (3:1) to receive 24 wk of treatment with DUAL (daclatasvir 60 mg once daily and asunaprevir 100 mg twice daily) beginning on day 1 of the treatment period (immediate treatment arm) or following 12 wk of matching placebo (placebo-deferred treatment arm). The primary endpoint was a comparison of sustained virologic response at posttreatment week 12 (SVR12) compared with the historical SVR rate for peg-interferon plus ribavirin (70%) among patients in the immediate treatment arm. The first 12 wk of the study were blinded. Safety was assessed in DUAL-treated patients compared with placebo patients during the first 12 wk (double-blind phase), and during 24 wk of DUAL in both arms combined.

RESULTS

In total, 207 patients were randomly assigned to immediate (n = 155) or placebo-deferred (n = 52) treatment. Most patients were Asian (86%), female (59%) and aged < 65 years (90%). Among them, 13% had cirrhosis, 32% had IL28B non-CC genotypes and 53% had baseline HCV RNA levels of ≥ 6 million IU/mL. Among patients in the immediate treatment arm, SVR12 was achieved by 92% (95% confidence interval: 87.2-96.0), which was significantly higher than the historical comparator rate (70%). SVR12 was largely unaffected by cirrhosis (89%), age ≥ 65 years (92%), male sex (90%), baseline HCV RNA ≥ 6 million (89%) or IL28B non-CC genotypes (96%), although SVR12 was higher among patients without (96%) than among those with (53%) baseline NS5A resistance-associated polymorphisms (at L31 or Y93H). During the double-blind phase, aminotransferase elevations were more common among placebo recipients than among patients receiving DUAL. During 24 wk of DUAL therapy (combined arms), the most common adverse events (≥ 10%) were elevated alanine aminotransferase and upper respiratory tract infection; emergent grade 3-4 laboratory abnormalities were infrequently observed, and all grade 3-4 aminotransferase abnormalities (alanine aminotransferase, n = 9; aspartate transaminase, n = 6) reversed within 8-11 d. Two patients discontinued DUAL treatment; one due to aminotransferase elevations, nausea, and jaundice and the other due to a fatal adverse event unrelated to treatment. There were no treatment-related deaths.

CONCLUSION

DUAL was well-tolerated during this phase 3 study, and SVR12 with DUAL treatment (92%) exceeded the historical SVR rate for peg-interferon plus ribavirin of 70%.

Usefulness of semiquantitative PCR-Invader assay for selecting candidates for daclatasvir plus asunaprevir combination therapy among patients with hepatitis C virus genotype 1b

AIMS

PCR-Invader is a highly sensitive assay for detecting non-structural protein 5A (NS5A) resistance-associated variants (RAVs) of hepatitis C virus (HCV). Here, we validated the accuracy of the semiquantitative PCR-Invader (SQ-PI) assay compared to direct sequencing (DS) for identifying NS5A RAVs, and we evaluated the treatment efficacy of daclatasvir plus asunaprevir (DCV + ASV) for patients judged to be non-positive for NS5A RAVs by SQ-PI.

METHODS

Detection rates of NS5A RAVs by SQ-PI and DS were compared for 204 patients with HCV genotype 1b. Patients with non-positive results for NS5A RAVs by SQ-PI were treated by DCV + ASV, and the efficacy of this treatment was examined.

RESULTS

All samples judged as negative for NS5A RAVs by SQ-PI were similarly judged by DS. However, 29.7% of samples judged as negative for Y93H by DS were judged as weakly positive or positive by SQ-PI. Among 108 patients who were judged as negative by SQ-PI and treated by DCV + ASV, rates of sustained virologic response at 24 weeks (SVR24) were 96.3% in intention-to-treat analysis and 99.0% in patients who completed treatment. Among patients who were weakly positive for Y93H on SQ-PI, the SVR24 rate was 95.0% (19/20). This rate was 100% (78/78) in patients who were negative for Y93H on SQ-PI and completed treatment.

CONCLUSION

Treatment efficacy of DCV + ASV was extremely high among patients who were non-positive for NS5A RAVs on SQ-PI, especially for patients with negative results.

Daclatasvir and asunaprevir treatment in patients infected by genotype 1b of hepatitis C virus with no or subtle resistant associated substitutions (RAS) in NS5A-Y93

In this study, we investigated the real-world data of the first approved interferon-free regimen in Japan, daclatasvir and asunaprevir (DCV+ASV), in chronic hepatitis C patients infected HCV genotype 1b with no or subtle amount of baseline resistant associated substitutions (RAS). Among 924 patients registered in our multicenter study, 750 patients who were proven not to be infected with NS5A-Y93H RAS by direct sequencing and to have no or subtle amount (less than 20%) of NS5A-Y93H RAS by probe assays (Cycleave or PCR invader assay) were included in this study. We investigated the anti-viral effect and factors associated with SVR12. In statistical analysis, P < 0.05 was considered as significant. The SVR12 rate in this population was 92.1% (562/618). Factors associated with SVR12 were male (odds ratio: 2.128; 95%CI: 1.134-4.000, P = 0.019); lower serum γGTP (odds ratio: 1.007; 95%CI: 1.002-1.012, P = 0.006); lower HCV-RNA (odds ratio: 1.848; 95%CI: 1.087-3.145, P = 0.023), and RVR (odds ratio: 6.250; 95%CI: 2.445-15.873, P < 0.001). No patients with γGTP ≧ 80 IU/L without RVR showed SVR12 (0/4, 0%) and one patients with γGTP ≧ 20-< 80 IU/L and HCV-RNA ≧ 6.5 logIU/mL without RVR (5/10, 50%) and two female patients with RVR but γGTP ≧ 80 IU/L and HCV-RNA ≧ 6.5 logIU/mL (7/13, 53.8%) showed a low SVR12 rate. In the present study, we showed a good viral response with DCV-ASV treatment and identified four predictive factors associated with SVR12. These four markers could be a good predictive markers for the viral effect of this treatment regimen in patients with no or subtle amount of RAS in NS5A-Y93.

Simeprevir and daclatasvir for 12 or 24 weeks in treatment-naïve patients with hepatitis C virus genotype 1b and advanced liver disease

BACKGROUND & AIMS

We investigated the efficacy and safety of simeprevir plus daclatasvir in treatment-naïve patients with chronic, genotype 1b hepatitis C virus infection and advanced liver disease, excluding patients with pre-defined NS5A resistance-associated substitutions.

METHODS

This phase II, open-label, single-arm, multicentre study included patients aged ≥18 years with advanced fibrosis or compensated cirrhosis (METAVIR F3/4). Patients with NS5A-Y93H or L31M/V resistance-associated substitutions at screening were excluded. Simeprevir (150 mg)+daclatasvir (60 mg) once daily was administered for 12 or 24 weeks; treatment could be extended to 24 weeks prior to or at the Week 12 visit. Primary efficacy endpoint was sustained virological response 12 weeks after the end of treatment.

RESULTS

A total of 106 patients were treated; 27% patients were aged >65 years, 39% had cirrhosis, 53% had estimated glomerular filtration rate 30-89 mL/min, 14% had diabetes, and 38% had arterial hypertension. Overall, 42/106 received 12 weeks of treatment and 64/106 received 24 weeks of treatment. Ninety-seven (92%) patients achieved a sustained virological response 12 weeks after the end of treatment. The reasons for failure were viral breakthrough (n=7) at weeks 4-16, early treatment discontinuation (n=1) and viral relapse (n=1). Seventy-four (70%) patients had ≥1 adverse event during treatment, including six (6%) patients with ≥1 serious adverse event. Three (3%) patients discontinued treatment owing to adverse events.

CONCLUSIONS

Simeprevir+daclatasvir demonstrated strong antiviral activity and was well-tolerated in patients with hepatitis C virus genotype 1b infection, advanced liver disease and a high prevalence of comorbidities. However, viral breakthrough occurred in seven patients, making this regimen unsatisfactory.

Real-life prevalence of resistance-associated variants against non-structural protein 5A inhibitors and efficiency of Daclatasvir + Asunaprevir therapy in Korean patients with genotype 1b hepatitis C

Background

Direct-acting antivirals (DAAs) for chronic hepatitis C (CHC) treatment are tolerable and highly effective in a shorter period of time than before. However, resistance-associated variants (RAVs) can affect the efficacy of DAAs. The aim of this study was to investigate the real-life prevalence of RAVs against non-structural protein 5A (NS5A) inhibitors in Korean patients with genotype 1b chronic hepatitis C.

Methods

All consecutive patients with CHC genotype 1b who underwent a RAV test at a single referral hospital were enrolled.

Results

A total of 142 patients (male 53, female 89) were tested for RAVs. The average age of the patients was 58 years. Liver cirrhosis was found in 34.5% (49/142) of patients, and 19.0% (29/142) of patients had previously undergone interferon-based treatment. Twenty-nine patients (20.4%) had RAVs (Y93 or L31). Y93H, L31, or Y93H with L31 were detected in 22 (15.5%), 8 (5.6%), and 1 (0.7%) patients, respectively. The presence of RAV was not affected by previous interferon-based treatment or by the existence of liver cirrhosis. Among 113 patients without baseline NS5A RAVs, 72 patients started daclatasvir (DCV) + asunaprevir (ASV) treatment and 95% (68/72) patients achieved virologic response at week 4. Virologic response at end of treatment and sustained virologic response at 12 weeks after treatment were achieved by 94% (68/72) and 94% (68/72), respectively.

Conclusions

In Korean patients with genotype 1b CHC, 20.4% (29 of 142) of patients showed RAVs against NS5A inhibitors. Patient without RAVs who received treatment with DCV + ASV showed high virologic response rates in Korea.

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.

Baseline quasispecies selection and novel mutations contribute to emerging resistance-associated substitutions in hepatitis C virus after direct-acting antiviral treatment

Resistance-associated substitutions (RASs) in hepatitis C virus (HCV) appear upon failure of treatment with direct-acting antivirals (DAAs). However, their origin has not been clarified in detail. Among 11 HCV genotype 1b patients who experienced virologic failure with asunaprevir (ASV)/daclatasvir (DCV), 10 had major NS5A L31M/V-Y93H variants after treatment. L31M/V-Y93H variants were detected as a minor clone before therapy in 6 patients and were the most closely related to the post-treatment variants by phylogenetic tree analysis in 4 patients. Next, to consider the involvement of a trace amount of pre-existing variants below the detection limit, we analysed human hepatocyte chimeric mice infected with DAA-naïve patient serum. L31V-Y93H variants emerged after treatment with ledipasvir (LDV)/GS-558093 (nucleotide NS5B inhibitor) and decreased under the detection limit, but these variants were dissimilar to the L31V-Y93H variants reappearing after ASV/DCV re-treatment. Finally, to develop an infection derived from a single HCV clone, we intrahepatically injected full-genome HCV RNA (engineered based on the wild-type genotype 1b sequence) into chimeric mice. A new Y93H mutation actually occurred in this model after LDV monotherapy failure. In conclusion, post-treatment RASs appear by 2 mechanisms: the selection of pre-existing substitutions among quasispecies and the generation of novel mutations during therapy.

Effect of minor populations of NS5A and NS5B resistance-associated variants on HCV genotype-3 response to daclatasvir plus sofosbuvir, with or without ribavirin

BACKGROUND

Treatment of hepatitis C virus (HCV) genotype 3 (GT3) is a medical priority. All-oral treatment of HCV GT3 with daclatasvir (DCV) and sofosbuvir (SOF), with or without ribavirin (RBV), is recommended by several treatment guidelines. The impact of HCV minority populations at amino acid positions in NS5A and NS5B associated with drug resistance on response to DCV+SOF±RBV was assessed in SOF-naive and SOF-experienced HCV patients.

METHODS

The presence of baseline NS5A or NS5B polymorphisms was assessed in 227 and 167 HCV-GT3-infected patients, respectively, from four clinical studies of DCV+SOF±RBV. Polymorphisms were identified at a sequencing detection threshold of ≥10%, and at ≥1% by next-generation sequencing (NGS) for a subset.

RESULTS

No SOF resistance-associated polymorphisms were detected at baseline. Among 58 patients with prospective baseline sequencing data at ≥10% and ≥1%, detectable NS5A substitutions at A30 (A30K/R/S/T/V), S62 (S62A/F/K/L/T) or Y93H were 38% more prevalent at ≥1% compared with ≥10% (55% [32/58] versus 41% [24/58] of patients), although sustained virological response (SVR) in patients with these substitutions remained the same at both sequencing thresholds (88%). Only one additional Y93H was detected at ≥1%; the patient achieved SVR. In two virological failures with baseline Y93H, a minority S62L substitution at baseline was enriched from <20% to ≥95% at failure. Treatment-emergent minority populations (at A30, L31, P32, P58 and E92) observed by NGS in four virological failures became undetectable by week 24 post-treatment.

CONCLUSIONS

Sequencing at a depth of ≥10% appears to be sufficient to predict HCV GT3 response to DCV+SOF±RBV.