Elbasvir and grazoprevir for chronic hepatitis C genotypes 1 and 4

Structural and Synthetic Aspects of Small Ring Oxa- and Aza-Heterocyclic Ring Systems as Antiviral Activities

Antiviral properties of different oxa- and aza-heterocycles are identified and properly correlated with their structural features and discussed in this review article. The primary objective is to explore the activity of such ring systems as antiviral agents, as well as their synthetic routes and biological significance. Eventually, the structure-activity relationship (SAR) of the heterocyclic compounds, along with their salient characteristics are exhibited to build a suitable platform for medicinal chemists and biotechnologists. The synergistic conclusions are extremely important for the introduction of a newer tool for the future drug discovery program.

Daclatasvir as a hepatitis C infection treatment option: an up-to-date evaluation

INTRODUCTION

Globally, it is estimated that 290,000 patients infected with hepatitis C virus (HCV) died from hepatitis C consequences, including cirrhosis and hepatocellular carcinoma in 2019. Although daclatasvir (DCV), combined with sofosbuvir (SOF), is effective in HCV patients, the new pan-genotypic combinations are considered by many as more cost-effective and successful in eradicating HCV infection.

AREAS COVERED

This review discusses the safety, efficacy, and cost-effectiveness of DCV as an HCV treatment option based on real-world studies and pharmacoeconomic evaluations.

EXPERT OPINION

Real-life studies suggest that SOF/DCV has acceptable sustained virological response and can be used successfully to manage HCV. Nonetheless, the use of SOF/DCV is limited by the longer treatment duration in genotype (GT)-3 patients and the need for ribavirin (RBV) in treatment-experienced patients which increases the likelihood of adverse effects. DCV is likely to remain as a therapeutic option for the management of GT-1, GT-2, and GT-4 patients in resource limited settings, while GT-3 patients are more likely to benefit from RBV-free direct-acting antiviral combinations such as SOF/velpatasvir for 12 weeks or glecaprevir/pibrentasvir for 8 weeks. The introduction of generics for these new pan-genotypic drugs would likely eliminate the need for SOF/DCV in the near future.

Treatment of hepatitis C virus infection with direct-acting antivirals plus ribavirin eliminates viral RNA from peripheral blood mononuclear cells and reduces virologic relapse in diverse hepatic parenchymal changes

Elimination of hepatitis C virus (HCV) may fail, leading to a non-response outcome because of inappropriate testing for viral RNA in peripheral blood mononuclear cells (PBMCs). Sequelae of HCV genotype 4 therapy with sofosbuvir and daclatasvir ± ribavirin were assessed in our study at the 12th week after end of treatment (EOT) by screening for viral genomic RNA in serum and PBMCs with correlation to hepatic parenchymal changes. We recruited 102 out of 2165 patients who had received sofosbuvir/daclatasvir, either alone (n = 1573) or together with ribavirin (n = 592). Subjects were classified into three groups based on testing by single-step reverse transcription PCR: group I, HCV negative in both serum and PBMCs (n = 25); group II, HCV positive in PBMCs only (n = 52); and group III, HCV positive in both serum and PBMCs (n = 25). Groups I and II (n = 77) were selected out of 2102 (every 27th subject), while group III (n = 25) were selected from every second or third serologic relapse (n = 63). The pre-sampling population (n = 2165) showed sustained virologic response (SVR) in 33.21%; serologic relapse in 2.91%; HCV RNA only in PBMCs (66.79%) compared to serologic relapses and potential cure (P < 0.0001); higher serologic (38 out of 63, P = 0.03210) and cellular (36 out of 52, P = 0.0002) relapses in dual therapy than in triple therapy. The post-sampling population (n = 102) showed more HCV relapses in dual (50 out of 60) than in triple (27 out of 42) therapy (P = 0.0351); increased HCV antisense RNA strand in relapses compared to positive-sense strands alone (P < 0.001); and significant SVR events in undetectable (15 out of 31) compared to early (10 out of 55, P = 0.0058) and cirrhotic liver tissue changes (0 out of 16, P = 0.0006). In summary, HCV treatment with sofosbuvir/daclatasvir is followed by higher rates of serologic and intracellular viral RNA relapse than treatment with sofosbuvir/daclatasvir plus ribavirin. Cellular and serum viral RNA relapses are accompanied by HCV-induced hepatic pathology. An increased SVR with no detectable liver tissue changes was observed after triple therapy due to elimination of HCV RNA from PBMCs.

Drug-Drug Interactions of Newly Approved Direct-Acting Antiviral Agents in Patients with Hepatitis C

Hepatitis C is a major health problem worldwide, frequently resulting in cirrhosis and increasing the risk of hepatocellular carcinoma significantly. In recent years, the advent of direct-acting antivirals (DAAs) has dramatically improved the therapeutic outcomes in hepatitis C patients. In the last two years, several new DAA combinations have been approved for the treatment of the hepatitis C virus (HCV) infection, including elbasvir/grazoprevir, sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir, and glecaprevir/pibrentasvir. The newly approved DAA regimens may be prescribed with other drugs simultaneously, increasing the potential of pharmacokinetic interactions. Therefore, the knowledge and management of drug-drug interactions (DDIs) with DAAs should be considered a key issue in HCV therapy. This review summarizes researches of DDIs focusing on newly approved DAAs (elbasvir, grazoprevir, velpatasvir, voxilaprevir, glecaprevir, pibrentasvir) for patients undergoing HCV treatment to provide clinical consideration for comedication. With respect to DDIs, newly approved DAA regimens, including elbasvir/grazoprevir, sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir, and glecaprevir/pibrentasvir, are safely applicable.

Dissection of two drug-targeted regions of Hepatitis C virus subtype 4a infecting Egyptian patients

Recently, treatment of HCV infection has been improved after the development of direct acting antivirals (DAAs) which target different viral proteins (NS3-4A, NS5A and NS5B). The activity and effectiveness of these DAAs are affected by the presence of resistance associated substitutions (RASs). This study aimed to characterize HCV genotypes circulating among Egyptian HCV patients, to dissect the full sequences of HCV NS3-4A and NS5B regions, and to characterize RASs associated with NS3-4A and NS5B inhibitors in HCV treatment-naïve patients. Genotyping of 80 HCV samples from treatment-naïve patients was done using restriction fragment length polymorphism and phylogenetic analysis based on some full NS5B sequences. Results showed the prevalence of HCV subtype 4a. Twenty four new full sequences of NS3-4A and NS5B regions of subtype 4a were deposited in the GenBank database. In general, the substitutions associated with NS3-4A-targeting drugs were absent predicting possible responsiveness of Egyptian HCV patients to these drugs. In addition, the absence of amino acid substitutions associated with resistance to Sofosbuvir may predict good response to treatment with Sofosbuvir. Some amino acid substitutions associated with resistance to different classes of non-nucleoside inhibitors were detected. Further investigations on treated Egyptian HCV patients may evaluate the effectiveness of the massively used drugs. Many predicted T-cell-binding epitopes in NS3-4A and NS5B regions were found to be highly conserved in the currently studied isolates; a finding that might be important for HCV vaccine development. We demonstrated potential NS3 epitopes that could be used in engineering T cells against HCV epitopes.

HCV genotypes and their determinative role in hepatitis C treatment

Nowadays, exposure to infectious diseases caused by pathogenic viruses has become one of the major human concerns in health fields. In the meantime, hepatitis viruses are associated with health problems, especially in liver tissue. So far, several types of these viruses have been known including: HAV, HBV, HCV, HDV, HEV, and HGV. Nevertheless, it seems that hepatitis C is the major viral infection among all of the hepatitis infections. The cirrhosis and hepatocellular carcinoma are known as the most important pathological complications of this virus, from which seven genotypes have been identified. However, among these genotypes, the incidence rate of genotypes 1 and 3 is more than others. In this review, we have investigated the relationship between all HCV genotypes and therapeutic responses against them. Regarding heterogeneity between hepatitis C genotypes, it is not possible to access an effective vaccine against this virus, and treatment is the only applicable strategy. Response to treatment is different among genotypes, and it has resulted that each genotype has a specific therapeutic regimen of itself. Therefore, it seems that determination of hepatitis C genotype, as a key tool, is essential in controlling therapeutic regimen, improving local control programs and eventually producing an effective vaccine.

Development and validation of a highly sensitive second derivative synchronous fluorescence spectroscopic method for the simultaneous determination of elbasvir and grazoprevir in pharmaceutical preparation and human plasma

Elbasvir and grazoprevir combination has been newly approved for the treatment of patients infected with hepatitis C virus.

[Treatment of chronic viral hepatitis C with direct acting antiviral agent: review]

HCV infection treatment regimens are viewed from positions of HCV life cycle and replication, effects of NS3/4A protease inhibitors and NS5A/NS5B inhibitors on HCV strain replication. Evolution of HCV treatment regimens from its discovery to modern DAA agents had led to substantial progress although drug resistance poses a new issue to be addressed.

Frequent Antiviral Treatment Failures in Patients Infected With Hepatitis C Virus Genotype 4, Subtype 4r

Hepatitis C virus (HCV) genotype 4 is highly heterogeneous. HCV subtype 4r has been suggested to be less responsive to direct-acting antiviral (DAA) drug treatment than other genotype 4 subtypes. Among 537 DAA-treated patients who experienced a virological failure (VF) in France between 2015 and 2018, 121 (22.5%) were infected with genotype 4 and 27 of them (22.3%) with subtype 4r; subtype 4r was thus over-represented as compared to its prevalence in the French general population. Population sequencing of the nonstructural protein (NS) 3, NS5A, and NS5B genes was performed in all subtype 4r patients at treatment failure and in 6 at baseline, whereas full-length HCV genome sequencing was performed in two baseline and three treatment failure samples by means of an original shotgun metagenomics method based on deep sequencing. At treatment failure, all subtype 4r patients harbored two to three dominant NS5A resistance-associated substitutions (RASs), including at least L28A/C/I/M/V and L30R. Among 13 patients exposed to sofosbuvir and an NS5A inhibitor (daclatasvir, ledipasvir, or velpatasvir), 5 (38.5%) also harbored NS5B S282C/T RASs at treatment failure. An additional patient harbored S282C/T RASs at treatment failure by deep sequencing. Prevalence of S282C/T RASs at treatment failure was significantly higher in patients infected with genotype 4r than with other genotypes, including other subtypes of genotype 4. Conclusion: The lower rates of sustained virological response in patients infected with subtype 4r are related to the frequent preexistence at treatment baseline and subsequent selection by DAA treatment of both NS5A and NS5B S282 RASs. Our study suggests that these patients should be identified and receive a triple DAA combination regimen as first-line treatment.

5' UTR and NS5B-based genotyping of hepatitis C virus in patients from Damietta governorate, Egypt

Chronic hepatitis C virus (HCV) infection is a main health problem in Egypt causing high rates of mortalities. Egypt has the highest HCV prevalence in the world, with specific HCV subtypes epidemic and circulating extensively in the country. Different antiviral therapy protocols have been implemented for treating Egyptian HCV patients. Due to the limited data about HCV in Egypt, this study aimed to genotype HCV strains circulating in the Nile Delta Damietta governorate and to investigate the variation in the nonstructural 5B (NS5B) region targeted by the newly approved antiviral drugs. Thirty HCV samples from treatment-naïve patients were genotyped by restriction fragment length polymorphism. Some samples were genotyped by direct sequencing of their 5' untranslated region (UTR) and NS5B regions. Phylogenetic analysis was also performed on the sequences of their NS5B regions. Fourteen new sequences have been deposited in the GenBank database. Results showed that subtype 4a was prevalent in addition to subtype 1g. None of the previously reported NS5B substitutions were detected in the sequenced isolates from treatment-naïve patients, which may be a good predictor for efficient treatment of HCV Egyptian patients with Sofosbuvir. Further studies on Sofosbuvir treated-HCV Egyptian patients are required to investigate whether any NS5B substitutions can confer resistance to treatment.

Application of different spectrophotometric methods for simultaneous determination of elbasvir and grazoprevir in pharmaceutical preparation

The first three UV spectrophotometric methods have been developed of simultaneous determination of two new FDA approved drugs namely; elbasvir and grazoprevir in their combined pharmaceutical dosage form. These methods include simultaneous equation, partial least squares with and without variable selection procedure (genetic algorithm). For simultaneous equation method, the absorbance values at 369 (λ_max of elbasvir) and 253nm (λ_max of grazoprevir) have been selected for the formation of two simultaneous equations required for the mathematical processing and quantitative analysis of the studied drugs. Alternatively, the partial least squares with and without variable selection procedure (genetic algorithm) have been applied in the spectra analysis because the synchronous inclusion of many unreal wavelengths rather than by using a single or dual wavelength which greatly increases the precision and predictive ability of the methods. Successfully assay of the drugs in their pharmaceutical formulation has been done by the proposed methods. Statistically comparative analysis for the obtained results with the manufacturing methods has been performed. It is noteworthy to mention that there was no significant difference between the proposed methods and the manufacturing one with respect to the validation parameters.