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

An update on direct antiviral agents for the treatment of hepatitis C

Introduction: The development of direct-acting antiviral (DAA) agents for the treatment of hepatitis C virus (HCV) infection has completely transformed the management of this disease. The advantages of using DAA therapies include high efficacy (sustained virological response (SVR) rate >95%) with minimal side effects, good tolerability, easy drug administration (once daily oral dosing), and short duration of treatment (8-12 weeks). This transformative nature of DAA therapy underpins the goal of the World Health Organization to eliminate HCV infection as a public health threat by 2030.Areas covered: This review seeks to address the current status of DAA therapies, including recent developments, current limitations, and future challenges.Expert opinion: The current DAA regimens, with their high effectiveness and safety profiles, have changed patient perception of HCV infection from a disease that requires complex evaluation and long-term monitoring to a disease that can be cured after one visit to the general practitioner. Despite the remarkably high success rate of DAAs, few patients (4-5%) fail to obtain SVR even after treatment. Five years ahead, the landscape of HCV treatment will undoubtedly continue to evolve, and more pan-genotypic treatment options will be available to all patients.

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.

Features of resistance-associated substitutions after failure of multiple direct-acting antiviral regimens for hepatitis C

Background & Aims

We aimed to clarify the features of resistance-associated substitutions (RASs) after failure of multiple interferon (IFN)-free regimens in HCV genotype 1b infections.

Methods

A total of 1,193 patients with HCV for whom direct-acting antiviral (DAA) treatment had failed were enrolled from 67 institutions in Japan. The RASs in non-structural protein (NS)3, NS5A, and NS5B were determined by population sequencing.

Results

Failure of 1, 2, and 3 regimens was observed in 1,101; 80; and 12 patients, respectively. Among patients with failure of 1 regimen, Y56H and D168V in NS3 were more frequently detected after failure of paritaprevir, whereas D168E was more frequently detected after failure of regimens including asunaprevir. R30H and L31-RAS in NS5A were frequently detected after failure of regimens including daclatasvir. The prevalence of Y93-RAS was high irrespective of the regimen. S282T RAS in NS5B was detected in 3.9% of ledipasvir/sofosbuvir failures. The prevalence of D168-RAS increased significantly according to the number of failed regimens (p <0.01), which was similar to that seen with L31-RAS and Y93-RAS. The prevalence of patients with RASs in either NS3 or NS5A, or in both, increased significantly with increasing numbers of failed regimens. The P32del, which is unique to patients for whom DAA had failed, was linked to the absence of Y93H, the presence of L31F, and previous exposure to IFN plus protease inhibitor regimens.

Conclusions

Failure of multiple DAA regimens can lead to the generation of multiple RASs in the NS3 and NS5A regions of the HCV 1b genome. These mutations contribute to viral resistance to multiple treatment regimens and, therefore, should be considered during decision making for treatment of chronic HCV.

Lay summary

Resistance-associated substitutions (RAS) in the genome of the hepatitis C virus are 1 of the major causes for failed treatment. We investigated RASs after failure of various treatments for chronic hepatitis C, and found that more complicated RASs accumulated in the viral genome with successive failed treatments. The highly resistant P32del RAS at NS5A region was uniquely found in patients for whom DAA treatments had failed, and was linked to the presence and absence of specific RASs.

Structure-activity relationships of fluorene compounds inhibiting HCV variants

Approximately 71 million people suffer from hepatitis C virus (HCV) infection worldwide. Persistent HCV infection causes liver diseases such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma, resulting in approximately 400,000 deaths annually. Effective direct-acting antiviral agents (DAAs) have been developed and are currently used for HCV treatment targeting the following three proteins: NS3/4A proteinase that cleaves the HCV polyprotein into various functional proteins, RNA-dependent RNA polymerase (designated as NS5B), and NS5A, which is required for the formation of double membrane vesicles serving as RNA replication organelles. At least one compound inhibiting NS5A is included in current HCV treatment regimens due to the high efficacy and low toxicity of drugs targeting NS5A. Here we report fluorene compounds showing strong inhibitory effects on GT 1b and 3a of HCV. Moreover, some compounds were effective against resistance-associated variants to DAAs. The structure-activity relationships of the compounds were analyzed. Furthermore, we investigated the molecular bases of the inhibitory activities of some compounds by the molecular docking method.

Real-world virological efficacy and safety of daclatasvir/asunaprevir/beclabuvir in patients with chronic hepatitis C virus genotype 1 infection in Japan

BACKGROUND

The virological efficacy and safety of the direct-acting antiviral (DAA) regimen consisting of daclatasvir, asunaprevir, and beclabuvir (DCV/ASV/BCV) for patients chronically infected with hepatitis C virus (HCV) genotype 1 have not been previously evaluated in Japanese real-world settings.

METHODS

In a Japanese nationwide multicenter study, the rate of sustained virologic response (SVR) and safety were analyzed in 91 patients who started the DCV/ASV/BCV regimen between November 2016 and July 2017. SVR rates were compared based on baseline patient characteristics.

RESULTS

More than 60% of patients had a history of failure to achieve SVR with interferon (IFN)-free DAA therapy. Overall, 50 of 91 patients (54.9%) achieved SVR. Multivariate analysis identified a history of failure with IFN-free DAA therapy and pretreatment HCV RNA levels as factors significantly associated with treatment failure. Whereas the SVR rate in patients without a history of IFN-free DAA therapy was 91.7% (33 of 36 patients), it was only 30.9% (17 of 55 patients) among patients with a history of IFN-free DAA therapy. The rate of discontinuation due to an adverse event was 4.4%.

CONCLUSIONS

Many patients treated with the DCV/ASV/BCV regimen have a history of a failure to achieve SVR with previous IFN-free DAA therapy. SVR rate was not as high as that in pre-approval clinical trial of this regimen in IFN-free DAA-naïve patients. In addition, most patients with a history of failure with IFN-free DAA therapy, particularly the DCV/ASV regimen, showed resistance to this regimen.

Real-world efficacy of glecaprevir plus pibrentasvir for chronic hepatitis C patient with previous direct-acting antiviral therapy failures

BACKGROUND

Combination therapy with glecaprevir (GLE) and pibrentasvir (PIB) has high efficacy for pan-genotypic hepatitis C virus (HCV)-infected patients. However, the efficacy of the therapy for failures to prior direct-acting antiviral (DAA) regimens in real-world practice is not well known.

METHODS

Thirty patients infected with HCV genotype 1b, 2a, 2b, or 3a who failed to respond during prior DAA therapies were treated with GLE/PIB for 12 weeks. HCV NS3 and NS5A drug resistance-associated variants (RAVs) were determined by direct sequencing.

RESULTS

Twenty-eight out of 30 patients (93.3%) achieved SVR12 by GLE/PIB treatment. SVR12 rates were similar between patients with and without advanced liver fibrosis (94.7% and 91.0%, respectively). All 9 patients with genotype 2a, 2b, or 3a HCV infection achieved SVR12. However, two genotype 1b HCV-infected patients who failed previous daclatasvir plus asunaprevir treatment experienced HCV relapse after the end of GLE/PIB treatment. Direct sequence analysis showed the presence of NS3-D168E plus NS5A-L31I/P58S/Y93H RAVs in one patient and NS5A-L31F/P32del RAVs in another patient before GLE/PIB treatment. In the former patient, NS3-D168E plus NS5A-L31I/P58S/Y93H RAVs persisted, and additional NS5A-L28M/V75A variants emerged after HCV relapse.

CONCLUSIONS

GLE/PIB treatment for HCV-infected patients who did not respond to prior DAA treatments was highly effective regardless of liver fibrosis stage. However, some genotype 1b HCV-infected patients, especially those with NS5A-P32del, may have low susceptibility to the treatment.

Antiviral Activities of Curcuma Genus against Hepatitis C Virus

Hepatitis C virus (HCV) infection is one of the major public health problems in the world. Even though the new agents are shown to increase the sustained virology response, however, there are still many people who cannot access the therapy due to the high cost. Moreover, the emergence of resistance and side effects presented the necessity to develop alternative treatment agents for HCV infection. Plants of the genus of curcuma are popular among traditional medicines in the world, including Indonesia. They have been used for many herb remedies and reported to possess many biological activities. Several plants from the curcuma genus were known as treatment agents in liver disease and jaundice. Our current study determines antiviral activities of Curcuma domestica, Curcuma xanthorrhiza, and Curcuma heyneana against HCV and further examines the mechanism of actions. Antiviral activity was performed by in vitro culture cells using Huh 7.5it cells and treated with the mixture of extract and virus JFH1. The effects of extracts in HCV life cycle were determined by mode of action analysis to examine the action of substances in the entry or post entry steps. The results revealed that ethanol extract of C. domestica, C. xanthorrhiza, and C. heyneana showed strong anti-HCV activities with IC50 values of 1.68 ± 0.05, 4.93 ± 0.42 and 5.49 ± 0.59 μg/mL, respectively without any cytotoxicity effect. Mode of action analysis demonstrated that of C. domestica and C. heyneana exhibit HCV in the entry step, while C. xanthorrhiza inhibit in the entry and post entry steps of HCV life cycle. Docking analysis to predict the interaction of curcumin, the main compound of curcuma genus, revealed a strong interaction between curcumin and 4GAG receptor, a protein involved in the entry step of HCV infection. Moreover, it was also reported to possess good interaction with 4EAW, an HCV NS5B, which plays an important role in HCV replication. These results suggested that C. domestica, C. xanthorrhiza, and C. Heyneana possessed strong inhibition against hepatitis C virus, therefore they may be good candidates for anti-HCV agents.