Hydroxychloroquine and COVID-19 - A narrative review.

COVID 19 infection is unarguably the worst pandemic of this century. Till date there is no promising drug and vaccine available to treat this deadly viral infection. In the early phase chloroquine phosphate and hydroxychloroquine sulphate have been used to fight this illness on the basis of handful observational and small randomized and small-randomized studies. The paucity of clinical evidences of an unequivocal beneficial effect of chloroquine and hydroxychloroquine on COVID-19 has resulted in the passionate use of the drug for moderate to severe cases only and stimulated the need for large clinical trials for this and other molecules. In this review, we describe in brief the mechanism of action, the clinical studies, factors for cardiac toxicity, guidelines and future directions for hydroxychloroquine use in management of COVID-19 infection.

Enzymes and Enzyme Inhibitors-Applications in Medicine and Diagnosis.

This is the first part of a Special Issue on enzymes and enzymes inhibitors and their applications in medicine and diagnosis [...].

Antiviral therapies for influenza.

PURPOSE OF REVIEW: The heavily suppressed global influenza activity during the coronavirus disease 2019 (COVID-19) pandemic is expected to return upon relaxation of travel restriction and nonpharmaceutical interventions (NPI). We reviewed the four marketed neuraminidase inhibitors (NAI e.g., oseltamivir, zanamivir, peramivir, laninamivir) and the only endonuclease inhibitor (baloxavir) on their clinical therapeutic effects and the ability of viral suppression in various groups of patients of different clinical settings based on the latest evidence. RECENT FINDINGS: Early initiation, preferably within 48 h of symptom onsets, of antiviral treatments with NAI and baloxavir, is crucial to produce favourable outcomes in patients with influenza infection. Updated evidence does not suggest routine use of combined antiviral agents in patients with influenza infection. Treatment-emergent resistant influenza variants may occur during NAI and baloxavir use, but it has no major impact on subsequent recovery. Early treatment of index patients with influenza infection and post-exposure prophylaxis in specific populations is crucial in preventing influenza transmission. SUMMARY: Antiviral therapy is the major defence therapeutically in the community and hospital settings to expedite early recovery and reduce influenza-related complications. Early treatment of index patients and post-exposure prophylaxis in susceptible close contacts may mitigate the spread of infection.

Influenza antivirals and their role in pandemic preparedness.

Effective antivirals provide crucial benefits during the early phase of an influenza pandemic, when vaccines are still being developed and manufactured. Currently, two classes of viral protein-targeting drugs, neuraminidase inhibitors and polymerase inhibitors, are approved for influenza treatment and post-exposure prophylaxis. Resistance to both classes has been documented, highlighting the need to develop novel antiviral options that may include both viral and host-targeted inhibitors. Such efforts will form the basis of management of seasonal influenza infections and of strategic planning for future influenza pandemics. This review focuses on the two classes of approved antivirals, their drawbacks, and ongoing work to characterize novel agents or combination therapy approaches to address these shortcomings. The importance of these topics in the ongoing process of influenza pandemic planning is also discussed.

SARS-CoV-2 couples evasion of inflammatory response to activated nucleotide synthesis.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolves rapidly under the pressure of host immunity, as evidenced by waves of emerging variants despite effective vaccinations, highlighting the need for complementing antivirals. We report that targeting a pyrimidine synthesis enzyme restores inflammatory response and depletes the nucleotide pool to impede SARS-CoV-2 infection. SARS-CoV-2 deploys Nsp9 to activate carbamoyl-phosphate synthetase, aspartate transcarbamoylase, and dihydroorotase (CAD) that catalyzes the rate-limiting steps of the de novo pyrimidine synthesis. Activated CAD not only fuels de novo nucleotide synthesis but also deamidates RelA. While RelA deamidation shuts down NF-κB activation and subsequent inflammatory response, it up-regulates key glycolytic enzymes to promote aerobic glycolysis that provides metabolites for de novo nucleotide synthesis. A newly synthesized small-molecule inhibitor of CAD restores antiviral inflammatory response and depletes the pyrimidine pool, thus effectively impeding SARS-CoV-2 replication. Targeting an essential cellular metabolic enzyme thus offers an antiviral strategy that would be more refractory to SARS-CoV-2 genetic changes.

Deubiquitinases: From mechanisms to their inhibition by small molecules.

Deubiquitinases (DUBs) are specialized proteases that remove ubiquitin from substrates or cleave within ubiquitin chains to regulate ubiquitylation and therefore play important roles in eukaryotic biology. Dysregulation of DUBs is implicated in several human diseases, highlighting the importance of DUB function. In addition, many pathogenic bacteria and viruses encode and deploy DUBs to manipulate host immune responses and establish infectious diseases in humans and animals. Hence, therapeutic targeting of DUBs is an increasingly explored area that requires an in-depth mechanistic understanding of human and pathogenic DUBs. In this review, we summarize the multiple layers of regulation that control autoinhibition, activation, and substrate specificity of DUBs. We discuss different strategies to inhibit DUBs and the progress in developing selective small-molecule DUB inhibitors. Finally, we propose a classification system of DUB inhibitors based on their mode of action.

Potential Novel Thioether-Amide or Guanidine-Linker Class of SARS-CoV-2 Virus RNA-Dependent RNA Polymerase Inhibitors Identified by High-Throughput Virtual Screening Coupled to Free-Energy Calculations.

SARS-CoV-2, or severe acute respiratory syndrome coronavirus 2, represents a new pathogen from the family of Coronaviridae that caused a global pandemic of COVID-19 disease. In the absence of effective antiviral drugs, research of novel therapeutic targets such as SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) becomes essential. This viral protein is without a human counterpart and thus represents a unique prospective drug target. However, in vitro biological evaluation testing on RdRp remains difficult and is not widely available. Therefore, we prepared a database of commercial small-molecule compounds and performed an in silico high-throughput virtual screening on the active site of the SARS-CoV-2 RdRp using ensemble docking. We identified a novel thioether-amide or guanidine-linker class of potential RdRp inhibitors and calculated favorable binding free energies of representative hits by molecular dynamics simulations coupled with Linear Interaction Energy calculations. This innovative procedure maximized the respective phase-space sampling and yielded non-covalent inhibitors representing small optimizable molecules that are synthetically readily accessible, commercially available as well as suitable for further biological evaluation and mode of action studies.

Baricitinib improves respiratory function in patients treated with corticosteroids for SARS-CoV-2 pneumonia: an observational cohort study.

OBJECTIVES: The Janus kinase (JAK) inhibitor baricitinib may block viral entry into pneumocytes and prevent cytokine storm in patients with SARS-CoV-2 pneumonia. We aimed to assess whether baricitinib improved pulmonary function in patients treated with high-dose corticosteroids for moderate to severe SARS-CoV-2 pneumonia. METHODS: This observational study enrolled patients with moderate to severe SARS-CoV-2 pneumonia [arterial oxygen partial pressure (PaO2)/fraction of inspired oxygen (FiO2) <200 mmHg] who received lopinavir/ritonavir and HCQ plus either corticosteroids (CS group, n = 50) or corticosteroids and baricitinib (BCT-CS group, n = 62). The primary end point was the change in oxygen saturation as measured by pulse oximetry (SpO2)/FiO2 from hospitalization to discharge. Secondary end points included the proportion of patients requiring supplemental oxygen at discharge and 1 month later. Statistics were adjusted by the inverse propensity score weighting (IPSW). RESULTS: A greater improvement in SpO2/FiO2 from hospitalization to discharge was observed in the BCT-CS vs CS group (mean differences adjusted for IPSW, 49; 95% CI: 22, 77; P < 0.001). A higher proportion of patients required supplemental oxygen both at discharge (62.0% vs 25.8%; reduction of the risk by 82%, OR adjusted for IPSW, 0.18; 95% CI: 0.08, 0.43; P < 0.001) and 1 month later (28.0% vs 12.9%, reduction of the risk by 69%, OR adjusted for IPSW, 0.31; 95% CI: 0.11, 0.86; P = 0.024) in the CS vs BCT-CS group. CONCLUSIONS: . In patients with moderate to severe SARS-CoV-2 pneumonia a combination of baricitinib with corticosteroids was associated with greater improvement in pulmonary function when compared with corticosteroids alone. TRIAL REGISTRATION: European Network of Centres for Pharmacoepidemiology and Pharmacovigilance, ENCEPP (EUPAS34966, http://www.encepp.eu/encepp/viewResource.htm? id = 34967).

Comparison of Antiviral Agents for Seasonal Influenza Outcomes in Healthy Adults and Children: A Systematic Review and Network Meta-analysis.

Importance: Antiviral treatment of influenza is recommended for patients with influenza-like illness during periods of community cocirculation of influenza viruses and SARS-CoV-2; however, questions remain about which treatment is associated with the best outcomes and fewest adverse events. Objective: To compare the efficacy and safety of neuraminidase inhibitors and the endonuclease inhibitor for the treatment of seasonal influenza among healthy adults and children. Data Sources: Medline, Embase, and the Cochrane Register of Clinical Trials were searched from inception to January 2020 (the last search was updated in October 2020). Study Selection: Included studies were randomized clinical trials conducted among patients of all ages with influenza treated with neuraminidase inhibitors (ie, oseltamivir, peramivir, zanamivir, or laninamivir) or an endonuclease inhibitor (ie, baloxavir) compared with other active agents or placebo. Data Extraction and Synthesis: Two investigators identified studies and independently abstracted data. Frequentist network meta-analyses were performed; relative ranking of agents was conducted using P-score probabilities. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations criteria. Data were analyzed in October 2020. Main Outcomes and Measures: The time to alleviation of influenza symptoms (TTAS), complications of influenza, and adverse events (total adverse events, nausea, and vomiting). Results: A total of 26 trials were identified that investigated antiviral drugs at high or low doses; these trials included 11 897 participants, among whom 6294 (52.9%) were men and the mean (SD) age was 32.5 (16.9) years. Of all treatments comparing with placebo in efficacy outcomes, high-quality evidence indicated that zanamivir was associated with the shortest TTAS (hazard ratio, 0.67; 95% CI, 0.58-0.77), while baloxavir was associated with the lowest risk of influenza-related complications (risk ratio [RR], 0.51; 95% CI, 0.32-0.80) based on moderate-quality evidence. In safety outcomes, baloxavir was associated with the lowest risk of total adverse events (RR, 0.84; 95% CI, 0.74-0.96) compared with placebo based on moderate-quality evidence. There was no strong evidence of associations with risk of nausea or vomiting among all comparisons, except for 75 mg oseltamivir, which was associated with greater occurrence of nausea (RR, 1.82; 95% CI, 1.38-2.41) and vomiting (RR, 1.88; 95% CI, 1.47-2.41). Conclusions and Relevance: In this systematic review and network meta-analysis, all 4 antiviral agents assessed were associated with shortening TTAS; zanamivir was associated with the shortest TTAS, and baloxavir was associated with reduced rate of influenza-related complications.

Promising Enzymes for Inhibitors Development Against COVID-19.

After the emergence of COVID-19 in 2019, it has now become a pandemic. COVID-19 has brought painful disasters to people all over the world. It not only threatens lives and health but also induces economic crises. At present, promising methods to eradicate COVID-19 mainly include drugs and vaccines. Enzyme inhibitors have always been a reliable strategy for the treatment of related diseases. Scientists worldwide have worked together to study COVID-19, obtained the structure of key SARS-CoV-2 associated enzymes, and reported the research of inhibitors of these enzymes. This article summarizes COVID-19-related enzyme inhibitors' recent development, mainly including 3CLpro, PLpro, TMPRSS2, and RdRp inhibitors, hoping to provide valuable weapons in the ensuing battle against COVID-19.

Efficacy and safety of dihydroorotate dehydrogenase (DHODH) inhibitors "leflunomide" and "teriflunomide" in Covid-19: A narrative review.

Dihydroorotate dehydrogenase (DHODH) is rate-limiting enzyme in biosynthesis of pyrimidone which catalyzes the oxidation of dihydro-orotate to orotate. Orotate is utilized in the biosynthesis of uridine-monophosphate. DHODH inhibitors have shown promise as antiviral agent against Cytomegalovirus, Ebola, Influenza, Epstein Barr and Picornavirus. Anti-SARS-CoV-2 action of DHODH inhibitors are also coming up. In this review, we have reviewed the safety and efficacy of approved DHODH inhibitors (leflunomide and teriflunomide) against COVID-19. In target-centered in silico studies, leflunomide showed favorable binding to active site of MPro and spike: ACE2 interface. In artificial-intelligence/machine-learning based studies, leflunomide was among the top 50 ligands targeting spike: ACE2 interaction. Leflunomide is also found to interact with differentially regulated pathways [identified by KEGG (Kyoto Encyclopedia of Genes and Genomes) and reactome pathway analysis of host transcriptome data] in cogena based drug-repurposing studies. Based on GSEA (gene set enrichment analysis), leflunomide was found to target pathways enriched in COVID-19. In vitro, both leflunomide (EC50 41.49 ± 8.8 µmol/L) and teriflunomide (EC50 26 µmol/L) showed SARS-CoV-2 inhibition. In clinical studies, leflunomide showed significant benefit in terms of decreasing the duration of viral shredding, duration of hospital stay and severity of infection. However, no advantage was seen while combining leflunomide and IFN alpha-2a among patients with prolonged post symptomatic viral shredding. Common adverse effects of leflunomide were hyperlipidemia, leucopenia, neutropenia and liver-function alteration. Leflunomide/teriflunomide may serve as an agent of importance to achieve faster virological clearance in COVID-19, however, findings needs to be validated in bigger sized placebo controlled studies.

Association Between FIASMAs and Reduced Risk of Intubation or Death in Individuals Hospitalized for Severe COVID-19: An Observational Multicenter Study.

Several medications commonly used for a number of medical conditions share a property of functional inhibition of acid sphingomyelinase (ASM), or FIASMA. Preclinical and clinical evidence suggest that the ASM/ceramide system may be central to severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection. We examined the potential usefulness of FIASMA use among patients hospitalized for severe coronavirus disease 2019 (COVID-19) in an observational multicenter study conducted at Greater Paris University hospitals. Of 2,846 adult patients hospitalized for severe COVID-19, 277 (9.7%) were taking an FIASMA medication at the time of their hospital admission. The primary end point was a composite of intubation and/or death. We compared this end point between patients taking vs. not taking an FIASMA medication in time-to-event analyses adjusted for sociodemographic characteristics and medical comorbidities. The primary analysis was a Cox regression model with inverse probability weighting (IPW). Over a mean follow-up of 9.2 days (SD = 12.5), the primary end point occurred in 104 patients (37.5%) receiving an FIASMA medication, and 1,060 patients (41.4%) who did not. Despite being significantly and substantially associated with older age and greater medical severity, FIASMA medication use was significantly associated with reduced likelihood of intubation or death in both crude (hazard ratio (HR) = 0.71, 95% confidence interval (CI) = 0.58-0.87, P < 0.001) and primary IPW (HR = 0.58, 95%CI = 0.46-0.72, P < 0.001) analyses. This association remained significant in multiple sensitivity analyses and was not specific to one particular FIASMA class or medication. These results show the potential importance of the ASM/ceramide system in COVID-19 and support the continuation of FIASMA medications in these patients. Double-blind controlled randomized clinical trials of these medications for COVID-19 are needed.

Medication safety in a pandemic: A multicentre point prevalence study of QTc monitoring of hydroxychloroquine for COVID-19.

WHAT IS KNOWN AND OBJECTIVE: A pandemic can strain all aspects of the healthcare system, including the ability to monitor the safety of medication use. Reviewing the adequacy of medication safety practices during the COVID-19 pandemic is critical to informing responses to future pandemics. The purpose of this study was to evaluate medication safety practices at a height of both COVID-19 cases and hydroxychloroquine use. METHODS: This was a multicentre observational point prevalence study. Adult inpatients receiving hydroxychloroquine for COVID-19 between March 22 and 28, 2020 were included. The primary outcome was the percentage of patients receiving appropriate QTc monitoring. Secondary outcomes included QTc prolongation, early discontinuation of hydroxychloroquine and ventricular arrhythmias. RESULTS AND DISCUSSION: A total of 59% (167/284) of patients treated with hydroxychloroquine received appropriate QTc monitoring. QTc prolongation occurred in 25%. Hydroxychloroquine was prematurely discontinued in 1.4% of patients, all due to QTc prolongation. Ventricular arrhythmia occurred in 1.1%. WHAT IS NEW AND CONCLUSION: Medication safety practices were suboptimal with regard to hydroxychloroquine monitoring at the height of the COVID-19 pandemic. Preparation for future pandemics should devote considerable attention to medication safety.

RNA-dependent RNA polymerase of SARS-CoV-2 as a therapeutic target.

The global pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), named coronavirus disease 2019, has infected more than 8.9 million people worldwide. This calls for urgent effective therapeutic measures. RNA-dependent RNA polymerase (RdRp) activity in viral transcription and replication has been recognized as an attractive target to design novel antiviral strategies. Although SARS-CoV-2 shares less genetic similarity with SARS-CoV (~79%) and Middle East respiratory syndrome coronavirus (~50%), the respective RdRps of the three coronaviruses are highly conserved, suggesting that RdRp is a good broad-spectrum antiviral target for coronaviruses. In this review, we discuss the antiviral potential of RdRp inhibitors (mainly nucleoside analogs) with an aim to provide a comprehensive account of drug discovery on SARS-CoV-2.

Identification of FDA approved drugs against SARS-CoV-2 RNA dependent RNA polymerase (RdRp) and 3-chymotrypsin-like protease (3CLpro), drug repurposing approach.

The RNA-dependent RNA polymerase (RdRp) and 3C-like protease (3CLpro) from SARS-CoV-2 play crucial roles in the viral life cycle and are considered the most promising targets for drug discovery against SARS-CoV-2. In this study, FDA-approved drugs were screened to identify the probable anti-RdRp and 3CLpro inhibitors by molecular docking approach. The number of ligands selected from the PubChem database of NCBI for screening was 1760. Ligands were energy minimized using Open Babel. The RdRp and 3CLpro protein sequences were retrieved from the NCBI database. For Homology Modeling predictions, we used the Swiss model server. Their structure was then energetically minimized using SPDB viewer software and visualized in the CHIMERA UCSF software. Molecular dockings were performed using AutoDock Vina, and candidate drugs were selected based on binding affinity (∆G). Hydrogen bonding and hydrophobic interactions between ligands and proteins were visualized using Ligplot and the Discovery Studio Visualizer v3.0 software. Our results showed 58 drugs against RdRp, which had binding energy of - 8.5 or less, and 69 drugs to inhibit the 3CLpro enzyme with a binding energy of - 8.1 or less. Six drugs based on binding energy and number of hydrogen bonds were chosen for the next step of molecular dynamics (MD) simulations to investigate drug-protein interactions (including Nilotinib, Imatinib and dihydroergotamine for 3clpro and Lapatinib, Dexasone and Relategravir for RdRp). Except for Lapatinib, other drugs-complexes were stable during MD simulation. Raltegravir, an anti-HIV drug, was observed to be the best compound against RdRp based on docking binding energy (-9.5 kcal/mole) and MD results. According to the MD results and binding energy, dihydroergotamine is a suitable candidate for 3clpro inhibition (-9.6 kcal/mol). These drugs were classified into several categories, including antiviral, antibacterial, anti-inflammatory, anti-allergic, cardiovascular, anticoagulant, BPH and impotence, antipsychotic, antimigraine, anticancer, and so on. The common prescription-indications for some of these medication categories appeared somewhat in line with manifestations of COVID-19. We hope that they can be beneficial for patients with certain specific symptoms of SARS-CoV-2 infection, but they can also probably inhibit viral enzymes. We recommend further experimental evaluations in vitro and in vivo on these FDA-approved drugs to assess their potential antiviral effect on SARS-CoV-2.

COVID-19: Antiviral agents and enzyme inhibitors/receptor blockers in development.

Novel 2019 coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) and coronavirus disease 2019 (COVID-19), the respiratory syndrome it causes, have shaken the world to its core by infecting and claiming the lives of many people since originating in December 2019 in Wuhan, China. World Health Organization and several states have declared a pandemic situation and state of emergency, respectively. As there is no treatment for COVID-19, several research institutes and pharmaceutical companies are racing to find a cure. Advances in computational approaches have allowed the screening of massive antiviral compound libraries to identify those that may potentially work against SARS-CoV-2. Antiviral agents developed in the past to combat other viruses are being repurposed. At the same time, new vaccine candidates are being developed and tested in preclinical/clinical settings. This review provides a detailed overview of select repurposed drugs, their mechanism of action, associated toxicities, and major clinical trials involving these agents.