Evolution and emergence of a new era of antiviral treatment for chronic hepatitis C infection

Design, Synthesis, Molecular Modeling Studies and Biological Evaluation of N'-Arylidene-6-(benzyloxy)-4-oxo-1,4-dihydroquinoline-3-carbohydrazide Derivatives as Novel Anti-HCV Agents

HCV-induced hepatitis is one of the most debilitating diseases. The limited number of anti-HCV drugs and drug-resistance necessitate developing of new scaffolds with different mode of actions. HCV non-structural protein 5B (NS5B) is an attractive target for development of novel inhibitors of HCV replication. In this paper, new N'-arylidene-6-(benzyloxy)-4-oxo-1,4-dihydroquinoline-3-carbohydrazide derivatives were designed based on the pharmacophores of HCV NS5B active site binding inhibitors. Designed compounds were synthesized and evaluated for their inhibitory activities in a cell-based HCV replicon system assay. Among tested compounds, compounds 18 and 20 were found to be the most active (EC50 = 35 and 70 µM, respectively) with good selectivity index (SI > 2) in the corresponding series. Molecular modeling studies showed that the designed compounds are capable of forming key coordination with the two magnesium ions as well as interactions with other key residues at the active site of HCV NS5B.

A Public Health Analysis on Gaps in Disease Monitoring and Opportunities for Improved Care for the Management of Hepatitis B and C

Hepatitis B and Hepatitis C have been major disease-causing agents among humans since they were discovered in the 1960s. Both cause jaundice-like symptoms initially but their prognosis and treatment are somehow different and depend upon many demographic details, such as the age and susceptibility of the patients and any other comorbid conditions. They clinically present primarily with hepatitis and can have many adverse effects or even be life-threatening at times, if not treated properly. However, their epidemiological background and findings in terms of morbidity, mortality, and case fatality rates are different. The disease burden, impact on the healthcare system, and prevention of the two diseases are quite different. The treatment and management options along with the prevention and control measures share unique strategies for handling the two diseases. The purpose of this review is to highlight the gaps in disease monitoring and to find ways and opportunities that can lead to improved care and better management of Hepatitis B and C locally and globally. Online databases were searched and peer-reviewed articles were selected. Key issues identified were lack of education globally in resource-limited settings, leading to a decreased understanding of the potential hazards associated with needle sharing and lack of access to healthcare because of a lack of insurance. The failure of compliance with vaccination leads to an increase in mother-to-child transmission (MTCT)-related infections. Increased global travel demands a systematic program in most immigrant-receiving countries to screen for hepatitis B virus (HBV)/hepatitis c virus (HCV) infections. Delayed U.S. Food and Drug Administration (FDA) licensing for new drugs hampers the treatment of chronic Hepatitis-B (CHB) among children. With the advancement in science, an effective vaccine against HCV will definitely help in eradicating the infection.

The discovery of IDX21437: Design, synthesis and antiviral evaluation of 2'-α-chloro-2'-β-C-methyl branched uridine pronucleotides as potent liver-targeted HCV polymerase inhibitors

Herein we describe the discovery of IDX21437 35b, a novel R_Pd-aminoacid-based phosphoramidate prodrug of 2'-α-chloro-2'-β-C-methyluridine monophosphate. Its corresponding triphosphate 6 is a potent inhibitor of the HCV NS5B RNA-dependent RNA polymerase (RdRp). Despite showing very weak activity in the in vitro Huh-7 cell based HCV replicon assay, 35b demonstrated high levels of active triphosphate 6 in mouse liver and human hepatocytes. A biochemical study revealed that the metabolism of 35b was mainly attributed to carboxyesterase 1 (CES1), an enzyme which is underexpressed in HCV Huh-7-derived replicon cells. Furthermore, due to its metabolic activation, 35b was efficiently processed in liver cells compared to other cell types, including human cardiomyocytes. The selected R_P diastereoisomeric configuration of 35b was assigned by X-ray structural determination. 35b is currently in Phase II clinical trials for the treatment of HCV infection.

Synthesis of potent and broad genotypically active NS5B HCV non-nucleoside inhibitors binding to the thumb domain allosteric site 2 of the viral polymerase

The hepatitis C virus (HCV) NS5B RNA-dependent RNA polymerase (RdRp) plays a central role in virus replication. NS5B has no functional equivalent in mammalian cells and, as a consequence, is an attractive target for selective inhibition. This Letter describes the discovery of a new family of HCV NS5B non-nucleoside inhibitors, based on the bioisosterism between amide and phosphonamidate functions. As part of this program, SAR in this new series led to the identification of IDX17119, a potent non-nucleoside inhibitor, active on the genotypes 1b, 2a, 3a and 4a. The structure and binding domain of IDX17119 were confirmed by X-ray co-crystallization study.

Design, synthesis and antiviral evaluation of 2'-C-methyl branched guanosine pronucleotides: the discovery of IDX184, a potent liver-targeted HCV polymerase inhibitor

BACKGROUND

Ribonucleoside analogs possessing a β-methyl substituent at the 2'-position of the d-ribose moiety have been previously discovered to be potent and selective inhibitors of hepatitis C virus (HCV) replication, their triphosphates acting as alternative substrate inhibitors of the HCV RdRp NS5B. Results/methodology: In this article, the authors detail the synthesis, anti-HCV evaluation in cell-based replicon assays and structure-activity relationships of several phosphoramidate diester derivatives of 2'-C-methylguanosine (2'-MeG).

CONCLUSION

The most promising compound, namely the O-[S-(hydroxyl)pivaloyl-2-thioethyl]{abbreviated as O-[(HO)tBuSATE)]} N-benzylamine phosphoramidate diester derivative (IDX184), was selected for further in vivo studies, and was the first clinical pronucleotide evaluated for the treatment of chronic hepatitis C up to Phase II trials.

Effect of Peginterferon or Ribavirin Dosing on Efficacy of Therapy With Telaprevir in Treatment-Experienced Patients With Chronic Hepatitis C and Advanced Liver Fibrosis: A Multicenter Cohort Study

We investigated the safety, efficacy, and impact of ribavirin and peginterferon dose reduction on complete early virologic response and sustained virologic response (SVR) to triple therapy with telaprevir in treatment-experienced patients with advanced liver fibrosis.Treatment was initiated for 211 patients who failed treatment with peginterferon and ribavirin, with bridging fibrosis (F3, n = 68) or cirrhosis (F4, n = 143), including 103 (49%) null-responders (NR), 30 (14%) partial responders (PR), and 78 (37%) relapsers (REL). Impaired liver function (ILF) platelets <100,000/mm or albumin <35 g/L were present in 40 patients. The distribution of hepatitis C virus subtypes was: 1a, 1b, or 1, with undetermined subtype for 10 (5%), 187 (89%), and 14 (6%) patients, respectively. Treatment was started with peginterferon alpha-2a or alpha-2b, ribavirin, and telaprevir at standard doses.The overall SVR24 rate was 56% and was lower in cirrhotic patients (NR: 35%, PR: 40%, and REL: 63%, respectively) than in patients with bridging fibrosis (NR: 50%, PR: 75%, and REL: 75%, respectively). The lowest probability of SVR24 was in NRs with ILF (26%). The SVR24 rate significantly decreased in NRs receiving <60% vs >60% of the total ribavirin dose (23% vs 44%, respectively) or <80% vs >80% of the total ribavirin dose (33% vs 48%, respectively). A significant SVR24 decrease was noted subsequent to a total peginterferon dose reduction, both when comparing patients who received <60% vs >60% of the total dose (NR: 0% vs 44%; REL: 33% vs 68%) and patients who received <80% vs >80% of the total dose (NR: 17% vs 50%; REL: 46% vs 71%).Serious adverse events were observed in 31 patients (15%). Deaths occurred in 4 patients. All of the deceased subjects were cirrhotic members of the ILF (baseline serum albumin level <35 g/L and/or platelet count <100,000/mm) group.Ribavirin dose reduction did not affect efficacy in REL but did in NR. Peginterferon dose reduction decreased the SVR24 rate for all groups, particularly in prior NR. ILF increased the risk of fatal complications with a low probability to achieve SVR24. One solution might be to provide wide and early access to novel, efficient, and safe interferon-free combinations to treatment-experienced patients, particularly those with liver cirrhosis.

The impact of the new antiviral regimens on patient reported outcomes and health economics of patients with chronic hepatitis C

Hepatitis C is an important cause of chronic liver disease worldwide with an estimated 170 million people infected. Hepatitis C virus (HCV)-infected patients are physically and mentally impacted by fatigue, depression and anxiety causing an impairment of health related quality of life (HRQOL), lower worker productivity and other patient reported outcomes (PROs). Although anti-HCV regimens containing first generation direct acting antiviral agents (DAAs) were associated with significant side effects, the second generation DAAs, sofosbuvir (SOF) and simeprevir (SMV), are associated with fewer side effects, better tolerability and high cure rates. Despite these advantages, key stakeholders are currently trying to find ways to best integrate these new therapeutic regimens into the management of patients with chronic hepatitis C for the benefit of all. The purpose of this article is to offer insight into the other key and equally important outcomes (PRO's, HRQOL and cost) which should be considered when assessing the applicability of these new regimens for the care of patients infected with HCV. Our review provides evidence that the new treatment regimens for HCV not only have high efficacy rates but are also associated with better patient reported outcomes and cost per case of HCV cured. Additionally, compared to other medical interventions, these new regimens are cost-effective from a societal perspective.