Virology analysis in HCV genotype 1-infected patients treated with the combination of simeprevir and TMC647055/ritonavir, with and without ribavirin, and JNJ-56914845

Targeting the SARS-CoV-2 spike glycoprotein prefusion conformation: virtual screening and molecular dynamics simulations applied to the identification of potential fusion inhibitors

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Up to now, there are no specific vaccines or drugs approved against COVID-19.

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Drug repurposing is a valuable method to identify small-molecule viral inhibitors.

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8770 FDA compounds have been screened using molecular docking and MD simulations.

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A selected set of drugs has been suggested as SARS-CoV-2 fusion inhibitors.

The emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to a renewed interest in studying the role of the spike S glycoprotein in regulating coronavirus infections in the natural host. Taking advantage of the cryo-electron microscopy structure of SARS-CoV-2 S trimer in the prefusion conformation, we performed a virtual screening simulation with the aim to identify novel molecules that could be used as fusion inhibitors. The spike glycoprotein structure has been completed using modeling techniques and its inner cavity, needful for the postfusion transition of the trimer, has been scanned for the identification of strongly interacting available drugs. Finally, the stability of the protein-drug top complexes has been tested using classical molecular dynamics simulations. The free energy of interaction of the molecules to the spike protein has been evaluated through the MM/GBSA method and per-residue decomposition analysis. Results have been critically discussed considering previous scientific knowledge concerning the selected compounds and sequence alignments have been carried out to evaluate the spike glycoprotein similarity among the betacoronavirus family members. Finally, a cocktail of drugs that may be used as SARS-CoV-2 fusion inhibitors has been suggested.

Genetic Polymorphisms within Interferon-λ Region and Interferon-λ3 in the Human Pathophysiology: Their Contribution to Outcome, Treatment, and Prevention of Infections with Hepatotropic Viruses

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Genetic polymorphisms within the interferon λ (IFN-λ) chromosomal region, mainly rs12979860 of IFN-λ4 gene (IFNL4), are known as associated with spontaneous hepatitis C virus (HCV) resolution and sustained viral response to therapy with pegylated interferon- α and ribavirin. Strong linkage disequilibrium of IFNL4 rs12979860 with IFNL4 rs368234815, which is casually associated with HCV spontaneous and therapeutical eradication, at least partially explains favorable HCV outcomes attributed to major homozygosity in rs12979860. Effects of IFN-based antiviral treatment are associated with pretreatment expression of the IFN-λ1 receptor, expression of hepatic IFN-stimulated genes, production of IFN- λ4, and preactivation of the JAK-STAT signaling. Nowadays direct-acting antivirals (DAAs) became a potent tool in the treatment of hepatitis C, but IFN-λs are still under investigation as potential antivirals and might be an option in HCV infection (DAA resistance, recurrent viremia, adverse effects).

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Patients with altered immunocompetence are especially prone to infections. In uremic subjects, polymorphisms within the IFN-λ chromosomal region associate with spontaneous HCV clearance, similarly like in the non-uremic population. Circulating IFN-λ3 shows a positive correlation with plasma titers of antibodies to surface antigen of hepatitis B virus (anti-HBs), which are crucial for protection against hepatitis B virus. More efficient anti-HBs production in the presence of higher IFN-λ3 levels might occur due to IFN-λ3-induced regulation of indoleamine 2,3-dioxygenase (IDO) expression. IFN-stimulated response element is a part of IDO gene promoter. It is worth further investigation whether IDO gene, circulating IDO, genetic polymorphisms within the IFN-λ region, and circulating IFN-λ3 act in concordance in immunological response to hepatotropic viruses.

NS5B polymerase inhibitors in phase II clinical trials for HCV infection

INTRODUCTION

Hepatitis C virus (HCV) infection might be the first chronic viral disease to be eradicated without the introduction of a prophylactic vaccine. This is essentially due to therapeutic revolution encapsulated by the advent of direct-acting antivirals (DAA) agents, whose efficacy, safety and tolerability (all oral regimens) have made the previous standard of care (interferon plus ribavirin) a vestige of the past. The new regimens achieve very high response rates and have an excellent tolerability profile. Notwithstanding, the first wave of DAAs has brought over problems regarding costs and failures which warrant research and development of further antiviral molecules.

AREAS COVERED

This review outlines the main clinical data concerning novel NS5B polymerase inhibitors currently in pipeline, focusing on the ones that have completed a phase 2 trial.

EXPERT OPINION

NS5B is one the main viral target for anti-HCV therapy. The large majority of the approved regimens so far include a NS5B inhibitor. Although not frequently, failure related to mutations can occur. The potential place in therapy in the mid-term of new NS5B inhibitors may be, in the first instance, the role of backbone in salvage combinations with DAAs of other classes.