Grazoprevir + elbasvir for the treatment of hepatitis C virus infection

The efficacy of Elbasvir/Grazoprevir fixed-dose combination for 8 weeks in HCV treatment and health-related quality of life (HRQoL) in treatment-naïve, non-cirrhotic, genotype 4-infected patients (ELEGANT-4): A single-center, single-arm, open-label, phase 3 trial

BACKGROUND

Cost, adverse events, and long treatment duration can be significant obstacles in treating hepatitis C virus (HCV)-infected individuals. Shortening the treatment regimen can minimize these barriers, thereby enhancing adherence and increasing medication availability to more patients.

METHODS

This is a single-centre, single-arm, open-label, phase 3 clinical trial on treatment naïve, non-cirrhotic, HCV genotype 4 patients. The study aimed to evaluate an 8-week course of Elbasvir (ELB)/Grazoprevir (GZR) in this population. The primary endpoint was sustained virologic response at 12 weeks after the end of treatment (SVR-12). The secondary endpoints were SVR-4, adverse events, and changes in health- and hepatitis-related quality of life (HRQoL).

RESULTS

Of the 30 patients who were enrolled, 29 (97%) achieved SVR-12 and SVR-4 (95% CI: 90-100%). No patients experienced serious or life-threatening adverse events (AEs), but mild/moderate AEs were reported by 16 (53%). The most commonly reported AEs were itching/skin rash (20%), headache (16.7%), abdominal/epigastric pain and decreased appetite (13.3% each), and nausea/vomiting (10%). Marked improvements in HRQoL were reported between the first (baseline) and third (SVR-12) timepoints. HRQoL score improvements involved the physical, mental, and hepatitis-specific indices, and ranged between 6 and 42 points (out of 100, P ≤0.003).

CONCLUSION

The trial provides empirical evidence that HCV genotype 4-infected patients can achieve viral eradication with an 8-week-regimen of ELB/GZR. Further, this course of treatment is associated with a minimal adverse event profile and potentially significant improvements in quality of life. (ClinicalTrials.gov number, NCT03578640).

SARS-CoV-2 spike protein and RNA dependent RNA polymerase as targets for drug and vaccine development: A review

The present pandemic has posed a crisis to the economy of the world and the health sector. Therefore, the race to expand research to understand some good molecular targets for vaccine and therapeutic development for SARS-CoV-2 is inevitable. The newly discovered coronavirus 2019 (COVID-19) is a positive sense, single-stranded RNA, and enveloped virus, assigned to the beta CoV genus. The virus (SARS-CoV-2) is more infectious than the previously detected coronaviruses (MERS and SARS). Findings from many studies have revealed that S protein and RdRp are good targets for drug repositioning, novel therapeutic development (antibodies and small molecule drugs), and vaccine discovery. Therapeutics such as chloroquine, convalescent plasma, monoclonal antibodies, spike binding peptides, and small molecules could alter the ability of S protein to bind to the ACE-2 receptor, and drugs such as remdesivir (targeting SARS-CoV-2 RdRp), favipir, and emetine could prevent SASR-CoV-2 RNA synthesis. The novel vaccines such as mRNA1273 (Moderna), 3LNP-mRNAs (Pfizer/BioNTech), and ChAdOx1-S (University of Oxford/Astra Zeneca) targeting S protein have proven to be effective in combating the present pandemic. Further exploration of the potential of S protein and RdRp is crucial in fighting the present pandemic.

Identification of potential inhibitors of three key enzymes of SARS-CoV2 using computational approach

The recent outbreak of coronavirus disease-19 (COVID-19) continues to drastically affect healthcare throughout the world. To date, no approved treatment regimen or vaccine is available to effectively attenuate or prevent the infection. Therefore, collective and multidisciplinary efforts are needed to identify new therapeutics or to explore effectiveness of existing drugs and drug-like small molecules against SARS-CoV-2 for lead identification and repurposing prospects. This study addresses the identification of small molecules that specifically bind to any of the three essential proteins (RdRp, 3CL-protease and helicase) of SARS-CoV-2. By applying computational approaches we screened a library of 4574 compounds also containing FDA-approved drugs against these viral proteins. Shortlisted hits from initial screening were subjected to iterative docking with the respective proteins. Ranking score on the basis of binding energy, clustering score, shape complementarity and functional significance of the binding pocket was applied to identify the binding compounds. Finally, to minimize chances of false positives, we performed docking of the identified molecules with 100 irrelevant proteins of diverse classes thereby ruling out the non-specific binding. Three FDA-approved drugs showed binding to 3CL-protease either at the catalytic pocket or at an allosteric site related to functionally important dimer formation. A drug-like molecule showed binding to RdRp in its catalytic pocket blocking the key catalytic residues. Two other drug-like molecules showed specific interactions with helicase at a key domain involved in catalysis. This study provides lead drugs or drug-like molecules for further in vitro and clinical investigation for drug repurposing and new drug development prospects.

Review on chemogenomic approaches towards hepatitis C viral targets

Hepatitis C virus (HCV) is the most prevalent viral pathogen that infects more than 185 million people worldwide. HCV infection leads to chronic liver diseases such as liver cirrhosis and hepatocellular carcinoma. Direct-acting antivirals (DAAs) are the recent combination therapy for HCV infection with reduced side effects than prior therapies. Sustained virological response (SVR) acts as a gold standard marker to monitor the success of antiviral treatment. Older treatment therapies attain 50-55% of SVR compared with DAAs which attain around 90-95%. The current review emphasizes the recent chemogenomic updates that have been unfolded through structure-based drug design of HCV drug target proteins (NS3/4A, NS5A, and NS5B) and ligand-based drug design of DAAs in achieving a stable HCV viral treatment strategies.

Clinical Pharmacokinetics and Drug-Drug Interactions of Elbasvir/Grazoprevir

Elbasvir and grazoprevir, in a fixed-dose combination of 50 and 100 mg, respectively, have received approval to be administered orally once daily, with or without ribavirin, for the treatment of chronic hepatitis C virus (HCV) infections. The absorption characteristics of elbasvir and grazoprevir have been adequately summarized, although differences were observed for grazoprevir (e.g., increased exposure at steady state in patients), but not elbasvir, between healthy and HCV-infected subjects. Inconsistencies with respect to absorption were also reported on the effects of food or acid reducers (famotidine or pantoprazole) in the literature. Many distribution characteristics of elbasvir and grazoprevir have been obtained from in vitro models, using incubation conditions that were in many cases inconsistent with normal physiological conditions in humans. Elbasvir and grazoprevir appear to undergo modest hepatic metabolism and are excreted primarily unchanged (~ 80% parent drug found) in feces. Both elbasvir and grazoprevir are substrates of cytochrome P450 (CYP) 3A4 enzyme, but mechanistic experiments were lacking to demonstrate the role of other enzymes and the precise relative % contribution of CYP3A4. The pharmacokinetics of elbasvir and grazoprevir have been characterized in various special populations (elderly, male vs. female, Caucasian vs. Asian, renal impairment, and hepatic impairment). Other than moderate and severe hepatic impairment where administrations are contraindicated, no dose adjustments are required for both drugs in these special patient populations. The available drug-drug interaction data provided some consistency between in vitro and in vivo observations and, in some instances, can provide predictions of likely clinically relevant scenarios.

Current and future challenges in HCV: insights from an Italian experts panel

BACKGROUND

The recent availability of direct acting antiviral drugs (DAAs) has drastically changed hepatitis C virus (HCV) treatment scenarios, due to the exceedingly high rates of sustained virological response (SVR) and excellent tolerability allowing for treatment at all disease stages.

METHODS

A panel of Italian experts was convened twice, in November 2016 and January 2017, to provide further support on some open issues and provide guidance for personalized HCV care, also in light of forthcoming regimens.

RESULTS AND CONCLUSIONS

Treatment recommendations issued by international and national liver societies to guide clinicians in the management of HCV infection are constantly updated due to accumulating new data. Such recommendations may not be applicable to all healthcare settings for a variety of reasons. Moreover, some gaps still remain and the spectrum of patients to be treated is also evolving.

Successful Treatment of Mixed Hepatitis C Genotypes in a Cirrhotic Patient With an All-Oral, Interferon-Free Regimen

Mixed hepatitis C virus (HCV) genotype infection is emerging with improved methods of detection. It is commonly seen in hemodialysis patients and intravenous drug users due to repeated HCV exposure and absence of protective immunity, and can contribute to treatment failure. Direct-acting antiviral regimens have been extensively studied in patients with different individual HCV genotypes; however, there are no reported data on their use in patients with mixed HCV genotype. We present a case of mixed HCV genotype 1a and 2 infection in a decompensated cirrhotic patient treated successfully with sofosbuvir, ledipasvir, and ribavirin.

Elbasvir and grazoprevir for chronic hepatitis C genotypes 1 and 4

INTRODUCTION

During the last few years, treatment of hepatitis C virus (HCV) revolutionized with the appearance of direct antiviral agents especially for patients with HCV genotypes 1 and 4 infections. Elbasvir (NS5A inhibitor) and grazoprevir (NS3/4A protease inhibitor) are newly developed drugs that are presented in fixed dose combination tablets. Areas covered: This review covers the mechanism of action, pharmacokinetic and pharmacodynamics properties, clinical uses, safety and efficacy of elbasvir/grazoprevir in managing a wide variety of easy and difficult to treat populations (such as presence of cirrhosis, treatment experienced, co-infection with HIV and patients with inherited blood disorders). Expert commentary: Elbasvir/grazoprevir combination showed great efficacy with high rates of sustained virological response rates in genotypes 1 and 4 HCV infection. In addition, it retained a good safety profile and is generally well tolerated.

2015 Philip S. Portoghese Medicinal Chemistry Lectureship. Curing Hepatitis C Virus Infection with Direct-Acting Antiviral Agents: The Arc of a Medicinal Chemistry Triumph

The development of direct-acting antiviral agents that can cure a chronic hepatitis C virus (HCV) infection after 8-12 weeks of daily, well-tolerated therapy has revolutionized the treatment of this insidious disease. In this article, three of Bristol-Myers Squibb's HCV programs are summarized, each of which produced a clinical candidate: the NS3 protease inhibitor asunaprevir (64), marketed as Sunvepra, the NS5A replication complex inhibitor daclatasvir (117), marketed as Daklinza, and the allosteric NS5B polymerase inhibitor beclabuvir (142), which is in late stage clinical studies. A clinical study with 64 and 117 established for the first time that a chronic HCV infection could be cured by treatment with direct-acting antiviral agents alone in the absence of interferon. The development of small molecule HCV therapeutics, designed by medicinal chemists, has been hailed as "the arc of a medical triumph" but may equally well be described as "the arc of a medicinal chemistry triumph".