Efficacy and safety of ledipasvir/sofosbuvir with ribavirin in chronic hepatitis C patients who failed daclatasvir/asunaprevir therapy: pilot study

BACKGROUND

In Japan, daclatasvir (DCV) and asunaprevir (ASV) therapy was the first IFN-free treatment to be approved, and thousands of patients have since been successfully treated, with an SVR rate of around 90%. The converse, however, is that around 10% of patients fail to achieve viral eradication and must be retreated using a different approach. This study is to evaluate treatment efficacy of ledipasvir/sofosbuvir and ribavirin in patients who failed to respond to DCV and ASV therapy.

METHODS

Thirty patients were treated with 12 weeks of ledipasvir/sofosbuvir and ribavirin. We evaluated the rate of sustained virological response 12 weeks after the end of treatment (SVR₁₂) and examined the incidence of adverse events during ledipasvir/sofosbuvir and ribavirin treatment. NS5A and NS5B resistance-associated variants (RAVs) in treatment failure cases were examined.

RESULTS

The overall SVR₁₂ rate was 86.7% (26/30). Large decreases in mean log₁₀ HCV RNA levels were observed in patients without cirrhosis, and the SVR₁₂ rate for these patients was 100% (12/12). In cases of cirrhosis, SVR₁₂ rate was 72.2% (13/18). The common factors in treatment failure cases were the presence of liver cirrhosis and both NS5A L31M/I and Y93H RAVs. The frequency of RAVs did not change before and after treatment among patients who relapsed.

CONCLUSION

Ledipasvir/sofosbuvir with ribavirin is an effective retreatment option for patients with chronic hepatitis C who failed to respond to prior daclatasvir and asunaprevir 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 of daclatasvir/asunaprevir according to resistance-associated variants in chronic hepatitis C with genotype 1

BACKGROUND

The present study explored the treatment outcome of daclatasvir (DCV) and asunaprevir (ASV) therapy combining oral direct-acting antiviral agents (DAAs) for chronic hepatitis C (HCV) including liver cirrhosis according to resistance-associated variants (RAVs) in NS3/NS5A region.

METHODS

Overall, 641 patients enrolled in Japan with HCV-1b received DCV and ASV for 24 weeks. Baseline drug-resistant mutations L31F/I/M/V, Q54H, P58S, A92K, and Y93H in the HCV NS5A region and V36A, T54A/S, Q80K/L/R, R155K/T/Q, A156S/V/T, and D168A/E/H/T/V in the HCV NS3/4A region were assessed by direct sequencing.

RESULTS

Overall, 86.9 % (543/625) of patients had SVR12, which was significantly higher in NS5A 93Y (wild) (88.3 %) compared with NS5A 93H at baseline (48.0 %), indicating the SVR12 rate was significantly lower in patients with 93H mutations. Additionally, 66.7 % (18/27) of patients with prior triple therapy including simeprevir (SMV) failure had virological failure. The virological failure rate of DCV/ASV therapy after SMV failure was significantly higher in those with preexisting NS3/4A 168 substitutions compared with without substitutions at baseline [84.2 % (16/19) vs. 28.6 % (2/7), p = 0.014]. The number of patients with multiple RAVs or deletions in NS5A increased from 0 to 85 % in failed patients. Alanine aminotransferase elevation was a frequent adverse event causing discontinuation of DCV/ASV therapy, although 87.5 % (14/16) patients achieved SVR12, subsequently.

CONCLUSIONS

History of SMV therapy and pre-existing NS5A Y93H were associated with virological failure of DCV/ASV therapy, resulting in the emergence of multiple RAVs. Patients with RAVs at baseline should be assessed to optimize future DAA therapies.

A profiling study of a newly developed HCVcc strain PR63cc's sensitivity to direct-acting antivirals

The development of direct-acting antivirals (DAAs) has significantly improved hepatitis C virus (HCV) treatment. However, drug resistance remains a potential concern in the real-world DAA-based therapies. We previously developed a novel full-length genotype 2a HCVcc clone PR63cc directly from clinical isolates. Here in this study, we compared the sensitivity of PR63cc and JFH1 to 12 different DAAs most of which are either already in clinical use or in the late clinical development phase. For NS5B inhibitors, PR63cc and JFH1 displayed comparable sensitivity to nucleoside/nucleotide analogues sofosbuvir and 2'-C-methyladenosine, while PR63cc was 4-fold more sensitive than JFH1 to nesbuvir, a non-nucleoside inhibitor. Interestingly, PR63cc and JFH1 were both completely resistant to dasabuvir which efficiently inhibited the replication of genotype 1b HCV replicon. For NS5A inhibitors, while PR63cc was as sensitive as JFH1 to ombitasvir and velpatasvir, it was much more resistant than JFH1 to daclatasvir and ledipasvir, which was mainly due to methionine at amino acid residue 31 of NS5A. For NS3 inhibitors, PR63cc was generally less sensitive than JFH1 to simeprevir, grazoprevir, asunaprevir and paritaprevir. Serine at residue 67 of NS3 was identified to be a resistance-associated variant (RAV) for asunaprevir. Finally, we showed that PR63cc was more resistant than JFH1 to the asunaprevir/daclatasvir combination treatment. In summary, our study systemically analyzed the DAA sensitivity of a new HCVcc strain and identified critical RAVs. These results are not only important for monitoring the emergence of drug-resistant mutations of current DAA therapies, but also valuable for developing next-generation DAAs.

Successful treatment of three patients with human immunodeficiency virus and hepatitis C virus genotype 1b co-infection by daclatasvir plus asunaprevir

Co-infection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) often accelerates the course of HCV-associated liver disease. Daclatasvir (DCV) plus asunaprevir (ASV) have been shown to be highly effective for HCV-infected patients with genotype 1b. Three patients co-infected with HIV/HCV genotype 1b were enrolled in this study. Prior to initiation of HCV treatment, the variants associated with L31 and Y93 in the non-structural protein 5A (NS5A) region of the HCV genome were confirmed to be absent using a direct sequencing method. Taking into consideration the lower risk of drug-drug interaction and the need for immediate treatment, the patients received 60 mg DCV once daily plus 100 mg ASV twice daily for 24 weeks. In one patient, the alanine aminotransferase level was elevated to 228 IU/L at 24 weeks after the start of treatment, but he completed the 24-week treatment course. All three patients achieved sustained viral response, without severe complications (including HIV virological rebound). Thus, in cases where NS5A variants are confirmed to be absent and patients are antiretroviral therapy-naïve, with CD4+ over 500/μL or HIV well controlled by RAL-based cART, DCV plus ASV may represent a good treatment option for HIV and HCV genotype 1b co-infected patients.

Second generation direct-acting antivirals - Do we expect major improvements?

The rapid progress in the development of direct-acting antiviral agents for hepatitis C has allowed the vast majority of patients to receive all oral therapy that will eliminate their virus. The success of the new regimens has led many to question the need for further developments in this field. Major improvements in drugs for hepatitis C are unlikely but we predict incremental improvements in the next few years. We hope that the next generation of drugs will address the unresolved issues for patients with genotype 3 infection where current treatments are still not entirely satisfactory and we anticipate improvements in the management of patients with renal failure. Shorter duration treatments, perhaps with novel modes of action, may allow simplified 'one-dose' treatments that will greatly expand our ability to treat patients who have difficulty accessing current services and we anticipate that the clinical community will better define the patients with advanced disease who will benefit from therapy prior to liver transplantation.

Naturally occurring NS3 resistance-associated variants in hepatitis C virus genotype 1: Their relevance for developing countries

Hepatitis C virus (HCV) is a major cause of global morbidity and mortality, with an estimated 130-150 million infected individuals worldwide. HCV is a leading cause of chronic liver diseases including cirrhosis and hepatocellular carcinoma. Current treatment options in developing countries involve pegylated interferon-α and ribavirin as dual therapy or in combination with one or more direct-acting antiviral agents (DAA). The emergence of resistance-associated variants (RAVs) after treatment reveals the great variability of this virus leading to a great difficulty in developing effective antiviral strategies. Baseline RAVs detected in DAA treatment-naïve HCV-infected patients could be of great importance for clinical management and outcome prediction. Although the frequency of naturally occurring HCV NS3 protease inhibitor mutations has been addressed in many countries, there are only a few reports on their prevalence in South America. In this study, we investigated the presence of RAVs in the HCV NS3 serine protease region by analysing a cohort of Uruguayan patients with chronic hepatitis C who had not been treated with any DAAs and compare them with the results found for other South American countries. The results of these studies revealed that naturally occurring mutations conferring resistance to NS3 inhibitors exist in a substantial proportion of Uruguayan treatment-naïve patients infected with HCV genotype 1 enrolled in these studies. The identification of these baseline RAVs could be of great importance for patients' management and outcome prediction in developing countries.

The importance of resistance to direct antiviral drugs in HCV infection in clinical practice

Treatment of chronic hepatitis C virus (HCV) infection with direct-acting antiviral agents (DAA) is associated with high rates of sustained virologic response. Remaining factors associated with treatment failure include advanced stages of liver fibrosis, response to previous antiviral therapy and viral factors such as baseline viral load and suboptimal interaction of the DAA with the target based on viral variants. Heterogeneity within NS3, NS5A, and NS5B areas interacting with DAAs exist between HCV geno- and subtypes as well as HCV isolates of the same geno- and subtype and amino acid polymorphisms associated with suboptimal efficacy of DAAs are termed resistance-associated variants (RAVs). RAVs may be associated with virologic treatment failure. However, virologic treatment failure typically occurs only if other negative predictive host or viral factors are present at the same time, susceptibility to additional antiviral agents is reduced or duration of treatment is suboptimal. In this review geno- and phenotypic resistance testing as well as clinical data on the importance of RAVs for conventional triple therapies with sofosbuvir, simeprevir, and daclatasvir and available interferon-free DAA combinations are discussed.

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.

The clinical features of patients with a Y93H variant of hepatitis C virus detected by a PCR invader assay

BACKGROUND

Resistance-associated variants (RAVs) reduce the efficacy of interferon (IFN)-free therapy with asunaprevir and daclatasvir for patients infected with hepatitis C virus (HCV) genotype 1b. The characteristics of patients with an L31 or a Y93 variant in the nonstructural 5A region detected by a polymerase chain reaction invader assay were investigated.

METHODS

In total, 201 patients with HCV genotype 1b were examined for L31F/M/V variants or a Y93H variant by the polymerase chain reaction invader assay.

RESULTS

L31M and Y93H variants were detected in 4.6 and 21.4 % of patients, respectively. Patients with an L31M variant had no significant characteristics. Patients with a Y93H variant had significantly higher HCV RNA levels (6.5 ± 0.5 log copies per milliliter vs 6.1 ± 0.7 log copies per milliliter, p = 0.0002), higher frequency of mutant type of the IFN-sensitivity-determining region (88.4 % vs 71.7 %, p = 0.0251), and higher frequency of TT genotype at rs8099917 of IL28B (91.7 % vs 54.3 %, p < 0.0001) than those with Y93 wild-type strains. Multivariate analysis identified HCV RNA levels [odds ratio (OR) 3.72, 95 % confidence interval (CI) 1.71-8.06, p = 0.0009] and TT genotype at rs8099917 (OR 7.45, 95 % CI 2.11-26.4, p = 0.0018) as factors associated with the presence of a Y93H variant.

CONCLUSION

The presence of a Y93H variant was associated with higher HCV RNA levels and TT genotype at rs8099917 of IL28B. Thus, patients with a Y93H variant may be ideal candidates for IFN-based therapy rather than IFN-free therapy, although the high viral load of these patients may reduce the response rate of IFN-based therapy.

Management of direct-acting antiviral agent failures

Failure to respond to the approved combinations of multiple direct-acting antiviral agents is relatively low in hepatitis C virus treatment registration studies, with rates of 1% to 7%, depending on the patients' baseline characteristics. In real life, failure is slightly higher, likely because of lower compliance. Treatment failures are usually related to relapse and less often to on-treatment viral breakthrough. Hepatitis C drug-resistant variants are detected in most patients who do not achieve viral eradication. The risk of developing these variants depends on host- and virus-related factors, the properties of the drugs used, and the treatment strategies applied. Patients who carry resistance-associated variants may not obtain benefits from treatment and are at risk of disease progression and transmission of the variants. Whether hepatitis C resistance-associated variants persist depends on their type: NS3-4A variants often disappear gradually after therapy is stopped, whereas NS5A variants tend to persist for more than 2 years. The best way to prevent emergence of resistant variants is to eliminate the virus at the first treatment using highly potent antivirals with genetic barriers to resistance. In patients failing first-generation protease inhibitors, combination therapies with sofosbuvir and NS5 inhibitors have proven effective. Some salvage regimens can be shortened to 12 weeks by addition of ribavirin. The optimal treatment for patients who fail an NS5A inhibitor and those with multidrug-resistant variants remains to be defined, and research efforts should continue to focus on treatment for these patients.

Next-Generation Regimens: The Future of Hepatitis C Virus Therapy

The treatment of chronic hepatitis C virus (HCV) has undergone a period of rapid evolution. The era of combination direct antivirals has led to high rates of sustained viral response (SVR), limited toxicities, and more broad applicability across patient demographics. Even current therapies have their limitations, however, including genotype specificity and variable durations of treatment depending on the presence or absence of cirrhosis. Developing a fixed-duration pangenotypic regimen that can broadly treat all stages of fibrosis with equal rates of SVR in all patients, irrespective of treatment experience, is the goal of future therapies. This article reviews antivirals in development.

Emergence of resistance-associated variants after failed triple therapy with vaniprevir in treatment-experienced non-cirrhotic patients with hepatitis C-genotype 1 infection: a population and clonal analysis

BACKGROUND

Vaniprevir with P/R improved SVR rates over P/R alone in treatment-experienced patients with chronic HCV-genotype 1 infection, but treatment failure presents therapeutic challenges. We identified RAVs from non-cirrhotic patients failing to achieve SVR on vaniprevir-containing regimens from a dose/duration-ranging trial of triple-combination therapy.

METHODS

Using population analysis, resistance sequencing was performed on all baseline samples and on samples at virologic failure in the vaniprevir arms. Longitudinal clonal analyses were performed on viral isolates from six vaniprevir recipients experiencing breakthrough viremia.

RESULTS

Baseline RAVs were detected in two patients subsequently experiencing virologic failure. At virologic failure, the majority of RAVs had substitutions at R155, A156, or D168. Clonal analyses identified novel double/triple variants emerging with continuing vaniprevir dosing.

CONCLUSIONS

RAVs were predominantly observed at R155, A156, and/or D168 during virologic failure on vaniprevir/P/R. Double/triple RAVs were identified in patients remaining viremic on triple therapy, suggesting evolution of resistance under selective pressure.