Toxic mechanisms of the antiviral drug arbidol on microalgae in algal bloom water at transcriptomic level

Increasing antivirals in surface water caused by their excessive consumption pose serious threats to aquatic organisms. Our recent research found that the input of antiviral drug arbidol to algal bloom water can induce acute toxicity to the growth and metabolism of Microcystis aeruginosa, resulting in growth inhibition, as well as decrease in chlorophyll and ATP contents. However, the toxic mechanisms involved remained obscure, which were further investigated through transcriptomic analysis in this study. The results indicated that 885-1248 genes in algae were differentially expressed after exposure to 0.01-10.0 mg/L of arbidol, with the majority being down-regulated. Analysis of commonly down-regulated genes found that the cellular response to oxidative stress and damaged DNA bonding were affected, implying that the stress defense system and DNA repair function of algae might be damaged. The down-regulation of genes in porphyrin metabolism, photosynthesis, carbon fixation, glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation might inhibit chlorophyll synthesis, photosynthesis, and ATP supply, thereby hindering the growth and metabolism of algae. Moreover, the down-regulation of genes related to nucleotide metabolism and DNA replication might influence the reproduction of algae. These findings provided effective strategies to elucidate toxic mechanisms of contaminants on algae in algal bloom water.

The Dual-Targeted Fusion Inhibitor Clofazimine Binds to the S2 Segment of the SARS-CoV-2 Spike Protein

Clofazimine and Arbidol have both been reported to be effective in vitro SARS-CoV-2 fusion inhibitors. Both are promising drugs that have been repurposed for the treatment of COVID-19 and have been used in several previous and ongoing clinical trials. Small-molecule bindings to expressed constructs of the trimeric S2 segment of Spike and the full-length SARS-CoV-2 Spike protein were measured using a Surface Plasmon Resonance (SPR) binding assay. We demonstrate that Clofazimine, Toremifene, Arbidol and its derivatives bind to the S2 segment of the Spike protein. Clofazimine provided the most reliable and highest-quality SPR data for binding with S2 over the conditions explored. A molecular docking approach was used to identify the most favorable binding sites on the S2 segment in the prefusion conformation, highlighting two possible small-molecule binding sites for fusion inhibitors. Results related to molecular docking and modeling of the structure-activity relationship (SAR) of a newly reported series of Clofazimine derivatives support the proposed Clofazimine binding site on the S2 segment. When the proposed Clofazimine binding site is superimposed with other experimentally determined coronavirus structures in structure-sequence alignments, the changes in sequence and structure may rationalize the broad-spectrum antiviral activity of Clofazimine in closely related coronaviruses such as SARS-CoV, MERS, hCoV-229E, and hCoV-OC43.

A guide to COVID-19 antiviral therapeutics: a summary and perspective of the antiviral weapons against SARS-CoV-2 infection

Antiviral therapies are integral in the fight against SARS-CoV-2 (i.e. severe acute respiratory syndrome coronavirus 2), the causative agent of COVID-19. Antiviral therapeutics can be divided into categories based on how they combat the virus, including viral entry into the host cell, viral replication, protein trafficking, post-translational processing, and immune response regulation. Drugs that target how the virus enters the cell include: Evusheld, REGEN-COV, bamlanivimab and etesevimab, bebtelovimab, sotrovimab, Arbidol, nitazoxanide, and chloroquine. Drugs that prevent the virus from replicating include: Paxlovid, remdesivir, molnupiravir, favipiravir, ribavirin, and Kaletra. Drugs that interfere with protein trafficking and post-translational processing include nitazoxanide and ivermectin. Lastly, drugs that target immune response regulation include interferons and the use of anti-inflammatory drugs such as dexamethasone. Antiviral therapies offer an alternative solution for those unable or unwilling to be vaccinated and are a vital weapon in the battle against the global pandemic. Learning more about these therapies helps raise awareness in the general population about the options available to them with respect to aiding in the reduction of the severity of COVID-19 infection. In this 'A Guide To' article, we provide an in-depth insight into the development of antiviral therapeutics against SARS-CoV-2 and their ability to help fight COVID-19.

Arbidol attenuates liver fibrosis and activation of hepatic stellate cells by blocking TGF-β1 signaling

Chronic liver diseases (CLD) impact over 800 million people globally, causing about 2 million deaths annually. Arbidol (ARB), an indole-derivative used to treat influenza virus infection, was extensively used during COVID-19 pandemic in China. In recent years, studies have shown that ARB, compared to other antiviral drugs, exhibits greater liver-protective efficacy, indicating a potential hepatoprotective effect beyond its antiviral activity. However, the mechanism remains unclear. In this study, we investigated the impact of ARB on liver injury/fibrosis in bile duct ligated (BDL) mice and its effect on spontaneous and transforming growth factor β1 (TGF-β1)-induced activation of primary cultured hepatic stellate cells (HSCs). Oral administration of ARB significantly ameliorated BDL-induced liver injury/fibrosis as reflected by decreased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), reduced collagen deposition, and diminished mRNA expression of fibrosis markers. ARB notably inhibited spontaneous and TGF-β1-induced activation of primary cultured HSCs. Moreover, ARB also drastically attenuated mRNA expression levels of platelet-derived growth factor receptor (Pdgfr), transforming growth factor-beta receptor (Tgfbr) 1, Tgfbr2, matrix metalloproteinase (Mmp)-2, and Mmp-9 in activated HSCs. We further demonstrate that ARB mitigated Smad2/3 phosphorylation in both TGF-β1 treated HSCs and BDL mice. These data together demonstrate that the therapeutic efficacy of ARB on liver fibrosis is independent of its antiviral activity and likely is achieved by blocking TGF-β1 signaling-mediated HSC activation.

The environmental risks of antiviral drug arbidol in eutrophic lake: Interactions with Microcystis aeruginosa

The environmental risks resulting from the increasing antivirals in water are largely unknown, especially in eutrophic lakes, where the complex interactions between algae and drugs would alter hazards. Herein, the environmental risks of the antiviral drug arbidol towards the growth and metabolism of Microcystis aeruginosa were comprehensively investigated, as well as its biotransformation mechanism by algae. The results indicated that arbidol was toxic to Microcystis aeruginosa within 48 h, which decreased the cell density, chlorophyll-a, and ATP content. The activation of oxidative stress increased the levels of reactive oxygen species, which caused lipid peroxidation and membrane damage. Additionally, the synthesis and release of microcystins were promoted by arbidol. Fortunately, arbidol can be effectively removed by Microcystis aeruginosa mainly through biodegradation (50.5% at 48 h for 1.0 mg/L arbidol), whereas the roles of bioadsorption and bioaccumulation were limited. The biodegradation of arbidol was dominated by algal intracellular P450 enzymes via loss of thiophenol and oxidation, and a higher arbidol concentration facilitated the degradation rate. Interestingly, the toxicity of arbidol was reduced after algal biodegradation, and most of the degradation products exhibited lower toxicity than arbidol. This study revealed the environmental risks and transformation behavior of arbidol in algal bloom waters.

Sunlight-induced degradation of COVID-19 antivirals arbidol in natural aquatic environments: Mechanisms, pathways and toxicity

Insights into COVID-19 antivirals' environmental fate and ecological risk are urgently required due to their increasing concentrations in aquatic environments, which have rarely been studied. Herein, we first investigated the photochemical transformation and the resulting alterations in toxicity of arbidol, an antiviral drug with relatively higher toxicity. The photolysis of arbidol was rapid with a rate constant of 0.106 min-1 due to its superior ultraviolet light absorption, in which the direct photolysis was predominated with a contribution of 91.5%. Despite its substantial photolysis, only 14.45% of arbidol was mineralized after 100 min, implying that arbidol and its products might have a long-term impact on aquatic environment. It was inferred that arbidol was photolyzed mainly via the loss of thiophenol, bromine, and alkylamine, based on twelve photolytic products identified. Notably, the experimental results demonstrated that the photolysis process increased the acute toxicity of arbidol, and the toxicity prediction indicated that the ecotoxicity of two photolytic products was very high with LC50 values below 0.1 mg/L. Due to the co-effect of multiple constituents, the photolytic rate observed in wastewater treatment plant effluent and in river water was comparable to that in ultra-pure water, while it was slightly enhanced in lake water. The presence of dissolved organic matter suppressed arbidol photolysis, while NO3- exhibited a promotion effect. These results would be of great significance to assess the fate and risk of COVID-19 antivirals in natural aquatic environments.

Real-world experience of arbidol for Omicron variant of SARS-CoV-2

Background

At a crucial time with the rapid spread of Omicron severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus variant globally, we conducted a study to evaluate the efficacy and safety of arbidol tablets in the treatment of this variant.

Methods

From Mar 26 to April 26, 2022, we conducted a prospective, open-labeled, controlled, and investigator-initiated trial involving adult patients with confirmed Omicron variant infection. Patients with asymptomatic or mild clinical status were stratified 1:2 to receive either standard-of-care (SOC) or SOC plus arbidol tablets (oral administration of 200 mg per time, three times a day for 5 days). The primary endpoint was the negative conversion rate within the first week.

Results

A total of 367 patients were enrolled in the study; 246 received arbidol tablet treatment, and 121 were in the control group. The negative conversion rate of SARS-CoV-2 within the first week in patients receiving arbidol tablets was significantly higher than that of the SOC group [47.2% (116/246) vs. 35.5% (43/121); odds ratio (OR), 1.619; 95% confidence interval (CI): 1.034-2.535; P=0.035]. Compared to those in the SOC group, patients receiving arbidol tablets had a shorter negative conversion time [median 8.3 vs. 10.0 days; hazard ratio (HR), 0.645; 95% CI: 0.516-0.808; P<0.001], and a shorter duration of hospitalization (median 11.4 vs. 13.7 days; HR, 1.214; 95% CI: 0.966-1.526; P<0.001). Moreover, the addition of arbidol tablets led to better recovery of declined blood lymphocytes, CD3⁺, CD4⁺, and CD8⁺ cell counts. The most common adverse event (AE) was transaminase elevation in patients treated with arbidol tablets (3/246, 1.2%). No one withdrew from the study due to AEs or disease progression.

Conclusions

As a whole, arbidol may represent an effective and safe treatment in asymptomatic-mild patients suffering from Omicron variant during the pandemic of coronavirus disease 2019 (COVID-19).

Conformational Screening of Arbidol Solvates: Investigation via 2D NOESY

Understanding of the nucleation process's fundamental principles in saturated solutions is an urgent task. To do this task, it is necessary to control the formation of polymorphic forms of biologically active compounds. In certain cases, a compound can exist in a single polymorphic form, but have several solvates which can appear in different crystal forms, depending on the medium and conditions of formation, and show different pharmaceutical activity. In the present paper, we report on the analysis of Arbidol conformational preferences in two solvents of different polarities-deuterated chloroform and dimethyl sulfoxide-at 25 °C, using the 2D NOESY method. The Arbidol molecule has various solvate forms depending on the molecular conformation. The method based on the nuclear Overhauser effect spectroscopy was shown to be efficient in the analysis of complex heterocyclic compounds possessing conformation-dependent pseudo-polymorphism. It is one of the types of polymorphism observed in compounds forming crystal solvates. Combined use of NMR methods and X-ray data allowed determining of conformer populations of Arbidol in CDCl₃ and DMSO-d₆ which were found to be 8/92% and 37/63%, respectively. The preferred conformation in solution is the same that appears in stable crystal solvates of Arbidol.

Hemagglutinin Stability Determines Influenza A Virus Susceptibility to a Broad-Spectrum Fusion Inhibitor Arbidol

Understanding mechanisms of resistance to antiviral inhibitors can reveal nuanced features of targeted viral mechanisms and, in turn, lead to improved strategies for inhibitor design. Arbidol is a broad-spectrum antiviral that binds to and prevents the fusion-associated conformational changes in the trimeric influenza A virus (IAV) hemagglutinin (HA). The rate-limiting step during the HA-mediated membrane fusion is the release of the hydrophobic fusion peptides from a conserved pocket on HA. Here, we investigated how destabilizing or stabilizing mutations in or near the fusion peptide affect viral sensitivity to Arbidol. The degree of sensitivity was proportional to the extent of fusion-peptide stability on the prefusion HA: stabilized mutants were more sensitive, and destabilized ones were resistant to Arbidol. Single-virion membrane fusion experiments for representative wild-type (WT) and mutant viruses demonstrated that resistance is a direct consequence of fusion-peptide destabilization not requiring reduced Arbidol binding to HA. Our results support the model whereby the probability of individual HAs extending to engage the target membrane is determined by the composite of two critical forces: a "tug" on the fusion peptide by HA rearrangements near the Arbidol binding site and the key interactions stabilizing the fusion peptide in the prefusion pocket. Arbidol increases and destabilizing mutations decrease the free-energy cost for fusion-peptide release, accounting for the observed resistance. Our findings have broad implications for fusion inhibitor design, viral mechanisms of resistance, and our basic understanding of HA-mediated membrane fusion.

Multi-target potential of Indian phytochemicals against SARS-CoV-2: A docking, molecular dynamics and MM-GBSA approach extended to Omicron B.1.1.529

BACKGROUND

SARS-CoV-2, an emerged strain of corona virus family became almost serious health concern worldwide. Despite vaccines availability, reports suggest the occurrence of SARS-CoV-2 infection even in a vaccinated population. With frequent evolution and expected multiple COVID-19 waves, improved preventive, diagnostic, and treatment measures are required. In recent times, phytochemicals have gained attention due to their therapeutic characteristics and are suggested as alternative and complementary treatments for infectious diseases. This present study aimed to identify potential inhibitors against reported protein targets of SARS-CoV-2.

METHODOLOGY

We computationally investigated potential SARS-CoV-2 protein targets from the literature and collected druggable phytochemicals from Indian Medicinal Plants, Phytochemistry and Therapeutics (IMPPAT) database. Further, we implemented a systematic workflow of molecular docking, dynamic simulations and generalized born surface area free-energy calculations (MM-GBSA).

RESULTS

Extensive literature search and assessment of 1508 articles identifies 13 potential SARS-CoV-2 protein targets. We screened 501 druggable phytochemicals with proven biological activities. Analysis of 6513(501 *13) docked phytochemicals complex, 26 were efficient against SARS-CoV-2. Amongst, 4,8-dihydroxysesamin and arboreal from Gmelina arborea were ranked potential against most of the targets with binding energy ranging between - 10.7 to - 8.2 kcal/mol. Additionally, comparative docking with known drugs such as arbidol (-6.6 to -5.1 kcal/mol), favipiravir (-5.5 to -4.5 kcal/mol), hydroxychloroquine (-6.5 to -5.1 kcal/mol), and remedesivir (-8.0 to -5.3 kcal/mol) revealed equal/less affinity than 4,8-dihydroxysesamin and arboreal. Interestingly, the nucleocapsid target was found commonly inhibited by 4,8-dihydroxysesamin and arboreal. Molecular dynamic simulation and Molecular mechanics generalized born surface area (MM-GBSA)calculations reflect that both the compounds possess high inhibiting potential against SARS-CoV-2 including the recently emerged Omicron variant (B.1.1.529).

CONCLUSION

Overall our study imparts the usage of phytochemicals as antiviral agents for SARS-CoV-2 infection. Additional in vitro and in vivo testing of these phytochemicals is required to confirm their potency.

Optimal Drug Regimen and Combined Drug Therapy and Its Efficacy in the Treatment of COVID-19: A Within-Host Modeling Study

The COVID-19 pandemic has resulted in more than 524 million cases and 6 million deaths worldwide. Various drug interventions targeting multiple stages of COVID-19 pathogenesis can significantly reduce infection-related mortality. The current within-host mathematical modeling study addresses the optimal drug regimen and efficacy of combination therapies in the treatment of COVID-19. The drugs/interventions considered include Arbidol, Remdesivir, Interferon (INF) and Lopinavir/Ritonavir. It is concluded that these drugs, when administered singly or in combination, reduce the number of infected cells and viral load. Four scenarios dealing with the administration of a single drug, two drugs, three drugs and all four are discussed. In all these scenarios, the optimal drug regimen is proposed based on two methods. In the first method, these medical interventions are modeled as control interventions and a corresponding objective function and optimal control problem are formulated. In this framework, the optimal drug regimen is derived. Later, using the comparative effectiveness method, the optimal drug regimen is derived based on the basic reproduction number and viral load. The average number of infected cells and viral load decreased the most when all four drugs were used together. On the other hand, the average number of susceptible cells decreased the most when Arbidol was administered alone. The basic reproduction number and viral load decreased the most when all four interventions were used together, confirming the previously obtained finding of the optimal control problem. The results of this study can help physicians make decisions about the treatment of the life-threatening COVID-19 infection.

Effective degradation of COVID-19 related drugs by biochar-supported red mud catalyst activated persulfate process: Mechanism and pathway

With the global spread of the COVID-19 pandemic, the water pollution caused by extensive production and application of COVID-19 related drugs has aroused growing attention. Herein, a novel biochar-supported red mud catalyst (RM-BC) containing abundant free hydroxyl groups was synthesized. The RM-BC activated persulfate process was firstly put forward to degrade COVID-19 related drugs, including arbidol (ARB), chloroquine phosphate, hydroxychloroquine sulfate, and acyclovir. Highly effective removal of these pharmaceuticals was achieved and even 100% of ARB was removed within 12 min at optimum conditions. Mechanism study indicated that SO₄ ^•- and HO^• were the predominant radicals, and these radicals were responsible for the formation of DMPOX in electron spin resonance experiments. Fe species (Fe⁰ and Fe₃O₄) and oxygen-containing functional groups in RM-BC played crucial roles in the elimination of ARB. Effects of degradation conditions and several common water matrices were also investigated. Finally, the degradation products of ARB were identified by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and possible degradation pathways were proposed. This study demonstrated that RM-BC/PS system would have great potential for the removal of COVID-19 related drug residues in water by the catalyst synthesized from the solid waste.

Antiviral drug Umifenovir (Arbidol) in municipal wastewater during the COVID-19 pandemic: Estimated levels and transformation

An indole derivative umifenovir (Arbidol) is one of the most widely used antiviral drugs for the prevention and treatment of COVID-19 and some other viral infections. The purpose of the present study was to shed light on the transformation processes of umifenovir in municipal wastewater, including disinfection with active chlorine, as well as to assess the levels of the antiviral drug and its metabolites entering and accumulating in natural reservoirs under conditions of the SARS-CoV-2 pandemic. The combination of high-performance liquid chromatography with electrospray ionization high-resolution mass-spectrometry and inductively coupled plasma mass spectrometry was used for tentative identification and quantification of umifenovir and its transformation products in model reaction mixtures and real samples of wastewater, river water, biological sludge and bottom sediments taken at the wastewater treatment plant in Arkhangelsk, a large cultural and industrial center at the Russian North. Laboratory experiments allowed identifying fifteen bromine-containing transformation products, forming at the initial stages of the chlorination and fourteen classic volatile and semi volatile disinfection by-products with bromoform as the dominant one. Chlorinated derivatives are only the minor disinfection by-products forming by substitution of alkylamine group in the aromatic ring. The schemes of umifenovir transformation in reactions with dissolved oxygen and sodium hypochlorite are proposed. Two established primary transformation products formed by oxidation of the thioether group to sulfoxide and elimination of thiophenol were detected in noticeable concentrations in the wastewater together with their precursor. The level of umifenovir reached 1.3 mg kg^-1 in the sludge and municipal wastewater treat contained 1 μg L^-1 of that drug, while its removal during biological wastewater treatment was about 40%. Pronounced accumulation of umifenovir and its transformation products in biological sludge and bottom sediments of natural reservoirs may be a source of the future secondary pollution of the environment.

Efficacy analysis of Arbidol treatment in patients with 2019 novel coronavirus pneumonia: a retrospective cohort study

BACKGROUND

The aim of this study was to determine whether Arbidol has a good antiviral effect on coronavirus disease 2019 (COVID-19).

METHODS

A retrospective cohort study was performed in one of the treatment centers for COVID-19 patients in China from January 2020 to March 2020. The antiviral drug Arbidol (ARB) was administrated to some of the patients at 0.2 g tid po for 7 to 10 days. According to whether patients were given ARB, they were divided into 2 groups: the ARB group and the Non-ARB group. The primary outcome was the 14-day COVID-19 negativity rate.

RESULTS

Of 146 patients, 140 were included. A total of 79 (56.4%) patients received ARB during hospitalization. In the overall cohort, the time of COVID-19 negativity in the ARB group compared with the Non-ARB group was 12.9 days versus 12.7 days (P=0.175; >0.05). The rates of 14-day COVID-19 negativity were 60.8% and 65.6% in the ARB and non-ARB groups, respectively (P=0.559; >0.05). Using an adjusted model, there were no obvious differences in the time of COVID-19 negativity and the rates of 14-day COVID-19 negativity (P>0.05). According to Kaplan-Meier analysis, the probabilities of 14-day COVID-19 negativity were similar in the 2 groups (log-rank P=0.130; >0.05). In a multivariate Cox analysis, the variables of age [hazard ratio (HR) 0.91, 95% confidence interval (CI): 0.83 to 0.99; P=0.039] and glucose (HR 0.90, 95% CI: 0.82 to 0.98; P=0.021) were independently associated with 14-day COVID-19 negativity.

CONCLUSIONS

Our results suggest that there was no apparent favorable clinical response with ARB both in clinical symptoms and the 14-day COVID-19 negativity rate.

Therapeutically effective covalent spike protein inhibitors in treatment of SARS-CoV-2

COVID-19 [coronavirus disease 2019] has resulted in over 204,644,849 confirmed cases and over 4,323,139 deaths throughout the world as of 12 August 2021, a total of 4,428,168,759 vaccine doses have been administered. The lack of potentially effective drugs against the virus is making the situation worse and dangerous. Numerous forces are working on finding an effective treatment against the virus but it is believed that a de novo drug would take several months even if huge financial support is provided. The only solution left with is drug repurposing that would not only provide effective therapy with the already used clinical drugs, but also save time and cost of the de novo drug discovery. The initiation of the COVID-19 infection starts with the attachment of spike glycoprotein of SARS-CoV-2 to the host receptor. Hence, the inhibition of the binding of the virus to the host membrane and the entry of the viral particle into the host cell are one of the main therapeutic targets. This paper not only summarizes the structure and the mechanism of spike protein, but the main focus is on the potential covalent spike protein inhibitors.

Efficacy of arbidol in COVID-19 patients: A retrospective study

BACKGROUND

To date, no treatment has proven to be absolutely effective for coronavirus disease 2019 (COVID-19) patients, and further research is necessary. As a traditional antiviral drug, arbidol was widely used in Wuhan at the beginning of the COVID-19 epidemic and is of increasing interest for treating COVID-19 based on in vitro data suggesting activity against severe acute respiratory syndrome (SARS). Although arbidol has been widely used in China to treat COVID-19 patients, clinical trials to date have not clearly substantiated this approach.

AIM

To evaluate the efficacy of arbidol for COVID-19.

METHODS

A retrospective study was conducted on 132 moderate and severe COVID-19 patients admitted to Jinyintan Hospital and Huoshenshan Hospital (officially designated for COVID-19 treatment) from February to March 2020 in Wuhan, China. This study mainly evaluated the efficacy of arbidol in patients with COVID-19 in the early stage of the SARS coronavirus 2 epidemic. Arbidol was administered at a dose of 200 mg, three times a day, with a 10-d course to adults not receiving any other drugs. Due to the shortage of beds at the time, not every patient could be admitted immediately. We looked for the early stages of the sudden outbreak, places of limited medical resources, limited ward beds, and delayed admission; thus, some patients naturally fit into the control group who did not receive any antiviral drugs. Out of the 132 patients, 72 received arbidol treatment, and 60 did not. We compared the disease course of the two groups and explored the predictors of extended disease duration.

RESULTS

Seventy-two patients commenced arbidol, and 60 patients did not receive arbidol treatment. The disease duration in the former group was shorter (23.42 ± 6.92 vs 29.60 ± 6.49, P < 0.001). Multivariate regression analysis showed that the risk of a prolonged course of disease increased by 7.158 times in the non-arbidol treatment group. Ferritin > 483.0 ng/mL and lactate dehydrogenase (LDH) > 237.5 U/L were found to be independent risk factors for protracted cases, with the risk of an extended disease duration increasing to 2.852 times and 5.946 times, respectively.

CONCLUSION

The duration course of moderate and severe COVID-19 patients is reduced by 6.183 d when arbidol is administered. Ferritin > 486.5 ng/mL and LDH > 239.5 U/L are independent risk factors for delayed recovery from COVID-19. Early oral administration of arbidol 200 mg t.i.d. with a 10-d course of treatment may be an effective management strategy in COVID-19 patients, particularly those with increased serum ferritin or elevated LDH.

Arbidol targeting influenza virus A Hemagglutinin; A comparative study

Influenza (flu) is a serious global health threat. The Hemagglutinin (HA) protein binds the flu virus to the sialic acids at the surface of the host cells' membrane which allows the endocytosis of the virus. Therefore, potential inhibitors can attach to the active site of HA and block the virus life-cycle. In this study, the antiviral drug arbidol (ARB) and 16 HA-subtypes were docked and analyzed to represent different approaches in predicting the conformation of protein-ligand, protein-protein, and protein-glycan complex and its binding energy. Our findings show that ARB interacts with all HA subtypes, and H₇ possesses the best affinity. The next influenza pandemic could be caused by H₄, H₅, H₆, and H₁₄ subtypes, which prompts further studies in investigating the interaction between these particular HA subtypes and other antiviral drugs to obtain higher efficacy.

Umifenovir in hospitalized moderate to severe COVID-19 patients: A randomized clinical trial

INTRODUCTION

The effectiveness of umifenovir against COVID-19 is controversial; therefore, clinical trials are crucial to evaluate its efficacy.

METHODS

The study was conducted as a single-center, randomized, open-label clinical trial. Eligible moderate-severe hospitalized patients with confirmed SARS-Cov-2 infection were randomly segregated into intervention and control groups. The intervention group were treated with lopinavir/ritonavir (400 mg/100 mg bid for 10-14 days) + hydroxychloroquine (400 mg single dose) + interferon-β1a (Subcutaneous injections of 44 µg (12,000 IU) on days 1, 3, 5) + umifenovir (200 mg trice daily for 10 days), and the control group received lopinavir/ritonavir (same dose) + hydroxychloroquine (same dose) + interferon-β1a (same dose).

RESULTS

Of 1180 patients with positive RT-PCRs and positive chest CT scans, 101 patients were finally included in the trial; 50 were assigned to receive IFNβ1a + hydroxychloroquine + lopinavir/ritonavir group and 51 were managed to treat with IFNβ1a + hydroxychloroquine + lopinavir/ritonavir + umifenovir. Since all patients received the intended treatment as scheduled, the analysis just included as the ITT population. Time to clinical improvement (TTCI) did not hold a statistically significant difference between intervention and control groups (median, 9 days for intervention group versus 7 days for the control group; P: 0.22). Besides, Hazard Ratio for TTCI in the Cox regression model was 0.75 (95% CI: 0.45-1.23, P:0.25) which also confirmed that there was no statistically significant difference between the treatment group and the control group. The mortality was not statistically significant between the two groups (38% in controls vs 33.3% treatment group).

CONCLUSIONS

Our findings shed new lights on the facts that additional umifenovir has not been found to be effective in shortening the duration of SARS-CoV-2 in severe patients and improving the prognosis in non-ICU patients and mortality.

TRIAL REGISTRATION

The trial was confirmed by the Ethics in Medical Research Committee of the Shahid Beheshti University of Medical Sciences. signed informed consents were obtained from all the participants or their legally authorized representatives. This trial has been registered as ClinicalTrials.gov, NCT04350684.

Antiviral drugs arbidol and interferon alpha-1b contribute to reducing the severity of COVID-19 patients: a retrospective cohort study

Objectives

The aim of this study was to evaluate the role of antiviral drugs in reducing the risk of developing severe illness in patients with moderate COVID-19 pneumonia.

Methods

This retrospective cohort study included 403 adult patients with moderate COVID-19 pneumonia who were admitted to Shenzhen Third People’s Hospital, China. The antiviral drugs arbidol, interferon alpha-1b, lopinavir–ritonavir and ribavirin were distributed to the patients for treatment. The primary endpoint of this study was the time to develop severe illness.

Results

Of the 462 patients admitted, 403 had moderate COVID-19 symptoms at hospital admission and were included in this study. 90 of the 403 (22.3%) patients progressed to severe illness. The use of arbidol was associated with a lower severity rate 3.5% compared to control group 30.5%, p-value < 0.0001; the adjusted hazard ratio was 0.28 (95% CI: 0.084–0.90, p = 0.033). The use of interferon alpha-1b was associated with a lower severity rate 15.5% compared to control group 29.3%, with p-value < 0.0001; the adjusted hazard ratio was 0.30 (95% CI: 0.15–0.58, p =  0.0005). The use of lopinavir–itonavir and ribavirin did not show significant differences in adjusted regression models. Early use of arbidol within 7 days of symptom onset was significantly associated with a reduced recovery time of − 5.2 days (IQR − 3.0 to − 7.5, p = 4e−06) compared with the control group.

Conclusion

Treatment with arbidol and interferon alpha-1b contributes to reducing the severity of illness in patients with moderate COVID-19 pneumonia. Early use of arbidol may reduce patients’ recovery time.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-021-01617-w.

Cyanorona-20: The first potent anti-SARS-CoV-2 agent

Explicit hindrance and blockade of the viral RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 is considered one of the most promising and efficient approaches for developing highly potent remedies for COVID-19. However, almost all of the reported viral RdRp inhibitors (either repurposed or new antiviral drugs) lack specific selectivity against the novel coronaviral RdRp and still at a beginning phase of advancement. Herein, I discovered and introduce a new pyrazine derivative, (E)-N-(4-cyanobenzylidene)-6-fluoro-3-hydroxypyrazine-2-carboxamide (cyanorona-20), as the first potent SARS-CoV-2 RdRp inhibitor with very high selectivity (209- and 45-fold more potent than favipiravir and remdesivir, respectively). This promising selective specific anti-COVID-19 compound is also deemed to be the first distinctive derivative of favipiravir. Cyanorona-20, the unprecedented nucleoside/nucleotide analog, was designed, synthesized, characterized, computationally studied, and biologically evaluated for its anti-COVID-19 actions (through a precise in vitro anti-COVID-19 assay). The results of the biological assay displayed that cyanorona-20 surprisingly exhibited very high and largely significant anti-COVID-19 activities (anti-SARS-CoV-2 EC₅₀ = 0.45 μM), and, in addition, it could be also a very promising guide and lead compound for the design and synthesis of new anti-SARS-CoV-2 and anti-COVID-19 agents through structural modifications and further computational studies. Further appraisal for the improvement of cyanorona-20 medication is a prerequisite requirement in the coming days. In a word, the ascent of the second member (cyanorona-20 “Corona Antidote”) of the novel and promising class of anti-COVID-19 pyrazine derivatives would drastically make a medical uprising in the pharmacotherapeutic treatment regimens and protocols of the recently-emerged SARS-CoV-2 infection and its accompanying COVID-19.

Comparison of the antiviral effect of Arbidol and Chloroquine in treating COVID-19

BACKGROUND

The novel coronavirus disease 2019 (COVID-19) was broken out in December 2019 and soon became a global health emergency. Effective treatment for COVID-19 is urgently needed. In the present study, we aimed to evaluate the antiviral effect of Arbidol vs. Chloroquine in treating COVID-19.

METHODS

We retrospectively analyzed 62 patients with COVID-19 diagnosed according to the guidelines for diagnosis and treatment of COVID-19 in China. They were divided into two groups depending on the antiviral drugs that they received. Participants in the Arbidol group (n=42) received 0.2 g Arbidol, tid for 10 days,and those in Chloroquine group (n=20) received 500 mg Chloroquine, bid for 10 days. The coronavirus negative conversion time and the length of hospital stay were analyzed and compared between the two groups.

RESULTS

There was no significant difference in demographic and clinical characteristics between the two groups. After antiviral treatment, the nasopharyngeal specimen negative conversion time of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the length of hospital stay in the Arbidol group were significantly shorter than those in the Chloroquine group (18.50 vs. 25.05 days, P=0.001; 23.52 vs. 28.75 days, P=0.001). Adverse events observed during the antiviral treatment period were comparable between the two groups. Overall, 3 (7.14%) participants in the Arbidol group and 4 (20.0%) in the Chloroquine group experienced adverse events during antiviral treatment.

CONCLUSIONS

These results suggest that Arbidol is advantageous over Chloroquine in terms of the SARS-CoV-2 negative conversion and the length of hospital stay in treating COVID-19 patients.

Beneficial effect of Arbidol in the management of COVID-19 infection

This study analyzed the effect of Arbidol, a broad-spectrum antiviral compound, on the outcomes of COVID-19 patients. Records of 252 COVID-19 patients were retrospectively analyzed from February 13 to February 29, 2020 in 4 inpatient wards in the Cancer Center, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China. The rate of clinical improvement was significantly greater among patients treated with Arbidol than among those who did not receive Arbidol (86.8% vs. 54.2%). In moderately and severely ill patients, the clinical improvement rates in the Arbidol group were 95.6% and 81.7%, respectively, which was significantly higher than in the no-Arbidol group (66.6% and 53.8%). Among critically ill patients, however, there was no significant difference. The levels of hypersensitive C-reactive protein, lactate dehydrogenase, D-dimer, IL-6, and IL-10 were increased in non-improved patients but declined during treatment in the improved patients. This suggests these mediators are associated with the disease severity and could potentially serve as prognostic markers. Moreover, our data demonstrate that Arbidol is effective in the treatment of COVID-19 patients and may serve as a cost-effective antiviral treatment strategy for patients with moderate to severe COVID-19 symptoms.

Clinical evaluation of Shufeng Jiedu Capsules combined with umifenovir (Arbidol) in the treatment of common-type COVID-19: a retrospective study

OBJECTIVE

To understand the clinical effectiveness and safety of Shufeng Jiedu Capsules combined with umifenovir (Arbidol) in the treatment of common-type COVID-19.

METHODS

A retrospective cohort study was used to analyze the case data of 200 inpatients diagnosed with common-type COVID-19 at Wuhan Hospital. Participants were divided into a control group and an experimental group. The control group was treated with Arbidol hydrochloride capsules while the experimental group was treated with combination Arbidol hydrochloride capsules and Shufeng Jiedu Capsules (SFJDC) for 14 days.

RESULTS

Defervescence was achieved more rapidly in the experimental group (P < 0.05). The white blood cell count and the lymphocyte percentage in the experimental group were higher than that of the control group (P < 0.05). CRP and IL-6 levels in the experimental group were significantly lower than those in the control group (P < 0.05). The proportion of chest CT studies showing resolution of pneumonia in the experimental group was significantly higher than that in the control group (P < 0.05).

CONCLUSIONS

A treatment regimen of Shufeng Jiedu Capsules combined with Arbidol to treat common-type COVID-19, combining traditional Chinese and western allopathic medicine, improves time to recovery, has better clinical effectiveness, and is safe.

A retrospective comparison of drugs against COVID-19

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Hydroxychloroquine is an efficient candidate drug against COVID-19.

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Oseltamivir can be prudently considered in combination therapy.

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Drug repurposing is a promising way to combat SARS-CoV-2 infection.

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Comparison of drug effects against COVID-19 is instructive in the pandemic.

Coronavirus disease 19 (COVID-19) has posed serious threats to the general population. To relieve the crisis, a comparison of drug effects against COVID-19 is instructive. Between January 27, 2020 and March 21, 2020, a total of 333 patients treated with arbidol, corticosteroids, hydroxychloroquine, lopinavir/ritonavir, or oseltamivir monotherapy, having definite outcomes and serological antibody detection results, were retrospectively analyzed. The hydroxychloroquine group had a significantly reduced duration of hospital stay than the arbidol and corticosteroids groups. The oseltamivir group had a significantly shorter length of hospital stay than the arbidol, corticosteroids, and lopinavir/ritonavir groups. The hydroxychloroquine group had a significantly higher IgM titer than the other four groups and exhibited significantly higher IgG levels than the arbidol, lopinavir/ritonavir, and oseltamivir groups. Our findings indicated that hydroxychloroquine might have the potential for efficient COVID-19 management, while oseltamivir should be prudently considered in combination therapy.

Effect of Arbidol (Umifenovir) on COVID-19: a randomized controlled trial

BACKGROUND

Treatment of patients with COVID-19 has included supportive care to mainly relief symptoms of the disease. Although World Health Organization (WHO) has not recommended any effective treatments for COVID-19, there are some reports about use of antiviral drugs. The aim of this study is to determine the effect of Arbidol (ARB) on COVID-19 disease.

METHODS

Using an open-label randomized controlled trial, we examined the efficacy of ARB in patients with COVID-19 in a teaching hospital. One hundred eligible patients with diagnosis of COVID-19 were recruited in the study and assigned randomly to two groups of either hydroxychloroquine followed by KALETRA (Lopinavir/ritonavir) or hydroxychloroquine followed by ARB. The primary outcome was hospitalization duration and clinical improvement 7 days after admission. The criteria of improvement were relief of cough, dyspnea, and fever. Time to relief from fever was also assessed across the two groups. Without any dropouts, 100 patients were entered into the study for the final analysis at significance level of 0.05.

RESULTS

The mean age of patients was 56.6 (17.8) years and 56.2 (14.8) years in ARB and KALETRA groups, respectively. Majority of patients were male across two groups (66 and 54%). The duration of hospitalization in ARB group was significantly less than KALETRA arm (7.2 versus 9.6 days; P = 0.02). Time to relief fever was almost similar across two groups (2.7 versus 3.1 days in ARB and KALETRA arms, respectively). Peripheral oxygen saturation rate was significantly different after 7 days of admission across two groups (94% versus 92% in ARB and KALETRA groups respectively) (P = 0.02). Based on multiple linear regression analysis, IHD, Na level, and oxygen saturation at the time of admission and type of therapy were the independent adjusted variables that determined the duration of hospitalization in patients with COVID-19.

CONCLUSION

Our findings showed that Arbidol, compared to KALETRA, significantly contributes to clinical and laboratory improvements, including peripheral oxygen saturation, requiring ICU admissions, duration of hospitalization, chest CT involvements, WBC, and ESR. We suggest further studies on ARB against COVID-19 using larger sample size and multicenter design.

TRIAL REGISTRATION

IRCT20180725040596N2 on 18 April 2020.

Scaffold morphing of arbidol (umifenovir) in search of multi-targeting therapy halting the interaction of SARS-CoV-2 with ACE2 and other proteases involved in COVID-19

The rapid emergence of novel coronavirus, SARS-coronavirus 2 (SARS-CoV-2), originated from Wuhan, China, imposed a global health emergency. Angiotensin-converting enzyme 2 (ACE2) receptor serves as an entry point for this deadly virus while the proteases like furin, transmembrane protease serine 2 (TMPRSS2) and 3 chymotrypsin-like protease (3CLpro) are involved in the further processing and replication of SARS-CoV-2. The interaction of SP with ACE2 and these proteases results in the SARS-CoV-2 invasion and fast epidemic spread. The small molecular inhibitors are reported to limit the interaction of SP with ACE2 and other proteases. Arbidol, a membrane fusion inhibitor approved for influenza virus is currently undergoing clinical trials against COVID-19. In this context, we report some analogues of arbidol designed by scaffold morphing and structure-based designing approaches with a superior therapeutic profile. The representative compounds A_BR4, A_BR9, A_BR18, A_BR22 and A_BR28 restricted the interaction of SARS-CoV-2 SP with ACE2 and host proteases furin and TMPRSS2. For 3CLPro, Compounds A_BR5, A_BR6, A_BR9 and A_BR18 exhibited high binding affinity, docking score and key residue interactions. Overall, A_BR18 and A_BR28 demonstrated multi-targeting potential against all the targets. Among these top-scoring molecules A_BR9, A_BR18, A_BR22 and A_BR28 were predicted to confer favorable ADME properties.

Comparative effectiveness of Lopinavir/Ritonavir-based regimens in COVID-19

The coronavirus disease 2019 (COVID-19) is an epidemic disease caused by the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) and spreading throughout the world rapidly. Here we evaluated the efficacy of the Lopinavir/Ritonavir (LPV/r) and its combination with other drugs in the treatment of COVID-19. We included 170 confirmed COVID-19 patients who had been cured and discharged. Their antiviral therapies were LPV/r alone or combinations with interferon (IFN), Novaferon and Arbidol. We evaluated the medication efficacy by comparing the time of the negative nucleic acid conversion and the length of hospitalization mainly. The LPV/r + Novaferon [6.00 (4.00-8.00) and 7.50 (5.00-10.00) days] had shorter time of the negative nucleic acid conversion (P = .0036) and shorter time of hospitalization (P < .001) compared with LPV/r alone [9.00 (5.00-12.00) and 12.00 (11.00-15.00) days] and LPV/r + IFN [9.00 (7.25-11.00) and 12.00 (10.00-13.50) days]. On the contrary, LPV/r + IFN [9.00 (7.25-11.00) and 12.00 (10.00-13.50) days] had shorter time of the negative nucleic acid conversion (P = .031) and shorter time of hospitalization (P < .001) compared with LPV/r + IFN +Novaferon [10.00 (8.00-11.25) and 13.50 (11.50-17.00) days] and LPV/r + IFN +Arbidol [14.00 (9.75-19.00) and 19.50 (13.25-24.00) days]. In conclusion, the combination of LPV/r and Novaferon may have better efficacy against COVID-19. However, adding IFN based on LPV/r + Novaferon or adding Arbidol based on LPV/r + IFN may not improve the efficacy.

Clinical features and efficacy of antiviral drug, Arbidol in 220 nonemergency COVID-19 patients from East-West-Lake Shelter Hospital in Wuhan: a retrospective case series

Objective

We aimed to describe the features of 220 nonemergency (mild or common type) COVID-19 patients from a shelter hospital, as well as evaluate the efficiency of antiviral drug, Arbidol in their disease progressions.

Methods

Basic clinical characteristics were described and the efficacy of Arbidol was evaluated based on gender, age, maximum body temperature of the patients.

Results

Basically, males had a higher risk of fever and more onset symptoms than females. Arbidol could accelerate fever recovery and viral clearance in respiratory specimens, particularly in males. Arbidol also contributed to shorter hospital stay without obvious adverse reactions.

Conclusions

In the retrospective COVID-19 cohort, gender was one of the important factors affecting patient's conditions. Arbidol showed several beneficial effects in these patients, especially in males. This study brought more researches enlightenment in understanding the emerging infectious disease.

Efficacy of Early Combination Therapy With Lianhuaqingwen and Arbidol in Moderate and Severe COVID-19 Patients: A Retrospective Cohort Study

Objective

Since the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Wuhan City, China, coronavirus disease 2019 (COVID-19) has become a global pandemic. However, no special therapeutic drugs have been identified for COVID-19. The aim of this study was to search for drugs to effectively treat COVID-19.

Materials and Methods

We conducted a retrospective cohort study with a total of 162 adult inpatients (≥18 years old) from Ruijin Hospital (Shanghai, China) and Tongji Hospital (Wuhan, China) between January 27, 2020, and March 10, 2020. The enrolled COVID-19 patients were first divided into the Lianhuaqingwen (LHQW) monotherapy group and the LHQW + Arbidol combination therapy group. Then, these two groups were further classified into moderate and severe groups according to the clinical classification of COVID-19.

Results

The early combined usage of LHQW and Arbidol can significantly accelerate the recovery of patients with moderate COVID-19 by reducing the time to conversion to nucleic acid negativity, the time to chest CT improvement, and the length of hospital stay. However, no benefit was observed in severe COVID-19 patients treated with the combination of LHQW + Arbidol. In this study, both Arbidol and LHQW were well tolerated without serious drug-associated adverse events.

Conclusion

The early combined usage of LHQW and Arbidol may accelerate recovery and improve the prognosis of patients with moderate COVID-19.

Systematic and Statistical Review of Coronavirus Disease 19 Treatment Trials

The following systematic review and meta-analysis compile the current data regarding human controlled COVID-19 treatment trials. An electronic search of the literature compiled studies pertaining to human controlled treatment trials with COVID-19. Medications assessed included lopinavir/ritonavir, arbidol, hydroxychloroquine, tocilizumab, favipiravir, heparin, and dexamethasone. Statistical analyses were performed for common viral clearance endpoints whenever possible. Lopinavir/ritonavir showed no significant effect on viral clearance for COVID-19 cases (OR 0.95 [95% CI 0.50–1.83]). Hydroxychloroquine also showed no significant effect on COVID-19 viral clearance rates (OR 2.16 [95% CI 0.80–5.84]). Arbidol showed no 7-day (OR 1.63 [95% CI 0.76–3.50]) or 14-day viral (OR 5.37 [95% CI 0.35–83.30]) clearance difference compared to lopinavir/ritonavir. Review of literature showed no significant clinical improvement with lopinavir/ritonavir, arbidol, hydroxychloroquine, or remdesivir. Tocilizumab showed mixed results regarding survival. Favipiravir showed quicker symptom improvement compared to lopinavir/ritonavir and arbidol. Heparin and dexamethasone showed improvement with severe COVID-19 cases requiring supplemental oxygenation. Current medications do not show significant effect on COVID-19 viral clearance rates. Tocilizumab showed mixed results regarding survival. Favipiravir shows favorable results compared to other tested medications. Heparin and dexamethasone show benefit especially for severe COVID-19 cases.

Candidate drugs against SARS-CoV-2 and COVID-19

Outbreak and pandemic of coronavirus SARS-CoV-2 in 2019/2020 will challenge global health for the future. Because a vaccine against the virus will not be available in the near future, we herein try to offer a pharmacological strategy to combat the virus. There exists a number of candidate drugs that may inhibit infection with and replication of SARS-CoV-2. Such drugs comprise inhibitors of TMPRSS2 serine protease and inhibitors of angiotensin-converting enzyme 2 (ACE2). Blockade of ACE2, the host cell receptor for the S protein of SARS-CoV-2 and inhibition of TMPRSS2, which is required for S protein priming may prevent cell entry of SARS-CoV-2. Further, chloroquine and hydroxychloroquine, and off-label antiviral drugs, such as the nucleotide analogue remdesivir, HIV protease inhibitors lopinavir and ritonavir, broad-spectrum antiviral drugs arbidol and favipiravir as well as antiviral phytochemicals available to date may limit spread of SARS-CoV-2 and morbidity and mortality of COVID-19 pandemic.

A study on clinical effect of Arbidol combined with adjuvant therapy on COVID-19

This study aims to explore the clinical effect of Arbidol (ARB) combined with adjuvant therapy on patients with coronavirus disease 2019 (COVID‐19). The study included 62 patients with COVID‐19 admitted to the First Hospital of Jiaxing from January to March 2020, and all patients were divided into the test group and the control group according to whether they received ARB during hospitalization. Various indexes in the two groups before and after treatment were observed and recorded, including fever, cough, hypodynamia, nasal obstruction, nasal discharge, diarrhea, C‐reactive protein (CRP), procalcitonin (PCT), blood routine indexes, blood biochemical indexes, time to achieve negative virus nucleic acid, and so on. The fever and cough in the test group were relieved markedly faster than those in the control group (P  <  .05); there was no obvious difference between the two groups concerning the percentage of patients with abnormal CRP, PCT, blood routine indexes, aspartate aminotransferase, and alanine aminotransferase (P > .05); the time for two consecutive negative nucleic acid tests in the test group were shorter than that in the control group; the hospitalization period of the patients in the test group and control group were (16.5  ±  7.14) days and (18.55  ±  7.52) days, respectively. ARB combined with adjuvant therapy might be able to relieve the fever of COVID‐19 sufferers faster and accelerate the cure time to some degree, hence it's recommended for further research clinically.

1.

Arbidol combined with adjuvant therapy could shorten the course of patient's basic symptoms;

2.

Arbidol combined with adjuvant therapy could normalize patient's temperature faster;

3.

Viral nucleic acid of patients treated with Arbidol combined with adjuvant therapy could turn negative within a shorter time.

Potential of Arbidol for Post-exposure Prophylaxis of COVID-19 Transmission: A Preliminary Report of a Retrospective Cohort Study

The efficient transmission of severe acute respiratory syndrome-2 coronavirus (SARS-CoV-2) from patients to health care workers or family members has been a worrisome and prominent feature of the ongoing outbreak. On the basis of clinical practice and in-vitro studies, we postulated that post-exposure prophylaxis (PEP) using Arbidol is associated with decreased infection among individuals exposed to confirmed cases of COVID-19 infection. We conducted a retrospective cohort study on family members and health care workers who were exposed to patients confirmed to have SARS-CoV-2 infection by real-time RT-PCR and chest computed tomography (CT) from January 1 to January 16, 2020. The last follow-up date was Feb. 26, 2020. The emergence of fever and/or respiratory symptoms after exposure to the primary case was collected. The correlations between post-exposure prophylaxis and infection in household contacts and health care workers were respectively analyzed. A total of 66 members in 27 families and 124 health care workers had evidence of close exposure to patients with confirmed COVID-19. The Cox regression based on the data of the family members and health care workers with Arbidol or not showed that Arbidol PEP was a protective factor against the development of COVID-19 (HR 0.025, 95% CI 0.003–0.209, P=0.0006 for family members and HR 0.056, 95% CI 0.005–0.662, P=0.0221 for health care workers). Our findings suggest Arbidol could reduce the infection risk of the novel coronavirus in hospital and family settings. This treatment should be promoted for PEP use and should be the subject of further investigation.

Arbidol/IFN-α2b therapy for patients with corona virus disease 2019: a retrospective multicenter cohort study

The spread of COVID-19 is accelerating. At present, there is no specific antiviral drugs for COVID-19 outbreak. This is a multicenter retrospective cohort study of patients with laboratory-confirmed COVID-19 infection pneumonia from 3 hospitals in Hubei and Guangdong province, 141 adults (aged ≥18 years) without ventilation were included. Combined group patients were given Arbidol and IFN-α2b, monotherapy group patients inhaled IFN-α2b for 10–14 days. Of 141 COVID-19 patients, baseline clinical and laboratory characteristics were similar between combined group and monotherapy group, that 30% of the patients leucocytes counts were below the normal range and 36.4% of the patients experienced lymphocytopenia. The duration of viral RNA of respiratory tract in the monotherapy group was not longer than that in the combined therapy group. There was no significant differences between two groups. The absorption of pneumonia in the combined group was faster than that in the monotherapy group. We inferred that Arbidol/IFN - 2 b therapy can be used as an effective method to improve the COVID-19 pneumonia of mild patients, although it helpless with accelerating the virus clearance. These results should be verified in a larger prospective randomized environment.

[Real-world efficacy and safety of lopinavir/ritonavir and arbidol in treating with COVID-19 : an observational cohort study]

Objective: To evaluate the efficacy and safety of lopinavir/ritonavir (LPV/r) and arbidol in the treatment of COVID-19 in the real world. Methods: The clinical data of 178 patients diagnosed with COVID-19 admitted to Guangzhou Eighth People's Hospital were retrospectively analyzed from January 21 to February 9, 2020. According to the patient's antiviral treatment regimen, 178 patients were divided into 4 groups including LPV/r group (59 patients), arbidol group (36 patients), combination therapy with LPV/r plus arbidol group (25 patients) and the conventional treatment group without any antiviral drugs (58 patients). The main observation end points of the study was the negative conversion time of nucleic acid of the novel coronavirus (2019-nCoV) in pharyngeal swab. Results: The baseline of 4 groups before treatment was consistent and comparable. The negative conversion time of nucleic acid of the 2019-nCoV in pharyngeal swab was (10.20 ± 3.49), (10.11 ± 4.68), (10.86 ± 4.74), (8.44 ± 3.51) days separately in the LPV/r group, the arbidol group, the combination therapy group, and the conventional treatment group without significant difference (F = 2.556, P = 0.058). There was also no significant difference in the rate of negative conversion rate of 2019-nCoV nucleic acid, the improvement ration in clinical symptoms, and the improvement ration of pulmonary infection in the lung CT imaging (P> 0.05). However, a statistically significant difference was found in the proportion of deterioration changing from mild/moderate to severe/critical type at day 7 (χ(2) = 9.311, P = 0.017) as follows: the combination therapy group (24.0%, 6/25), the arbidol group ( 16.7%, 6/36), LPV/r group (5.4%, 3/56) and conventional treatment group (5.2%, 3/58). Moreover, the frequency of adverse reactions in the three groups receiving antiviral drugs was significantly higher than that in the conventional treatment group (χ(2) = 14.875, P = 0.002). Conclusions: No evidences could prove that LPV/r and arbidol could shorten the negative conversion time of novel coronavirus nucleic acid in pharyngeal swab nor improve the symptoms of patients. Furthermore, the combination usage of LPV/r and arbidol may not benefit for improving the disease. Noteworthy, the adverse reactions of the antiviral drugs should be paid careful attention during the treatment.

Umifenovir treatment is not associated with improved outcomes in patients with coronavirus disease 2019: a retrospective study

Objectives

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Umifenovir (Arbidol®) is an antiviral drug being used to treat influenza in Russia and China. This study aimed to investigate the effectiveness and safety of umifenovir for COVID-19.

Methods

A retrospective study was performed in a non-intensive care unit (ICU) ward in Jinyintan Hospital from 2 February 2020 to 20 March 2020. COVID-19 was confirmed by real-time reverse-transcriptase polymerase chain reaction (RT-PCR) assay of pharyngeal swab specimens. The confirmed patients were divided into the umifenovir group and the control group according to the use of umifenovir. The main outcomes were the rate of negative pharyngeal swab tests for SARS-CoV-2 within 1 week after admission and the time for the virus to turn negative. The negativity time of SARS-CoV-2 was defined as the first day of a negative test if the nucleic acid of SARS-CoV-2 was negative for two consecutive tests.

Results

A total of 81 COVID-19 patients were included, with 45 in the umifenovir group and 36 in the control group. Baseline clinical and laboratory characteristics were comparable between the two groups. Thirty-three out of 45 (73%) patients in the umifenovir group tested negative for SARS-CoV-2 within 7 days after admission, the number was 28/36 (78%) in the control group (p 0.19). The median time from onset of symptoms to SARS-CoV-2 turning negative was 18 days (interquartile range (IQR) 12–21) in the umifenovir group and 16 days (IQR 11–21) in the control group (p 0.42). Patients in the umifenovir group had a longer hospital stay than patients in the control group (13 days (IQR 9–17) vs 11 days (IQR 9–14), p 0.04). No deaths or severe adverse reactions were found in both groups.

Discussion

Umifenovir might not improve the prognosis or accelerate SARS-CoV-2 clearance in non-ICU patients. A randomized control clinical trial is needed to assess the efficacy of umifenovir.

Arbidol combined with LPV/r versus LPV/r alone against Corona Virus Disease 2019: A retrospective cohort study

Background

Corona Virus Disease 2019 (COVID-19) due to the 2019 novel coronavirus (SARS-CoV-2) emerged in Wuhan city and rapidly spread throughout China. We aimed to compare arbidol and lopinavir/ritonavir(LPV/r) treatment for patients with COVID-19 with LPV/r only.

Methods

In this retrospective cohort study, we included adults (age≥18years) with laboratory-confirmed COVID-19 without Invasive ventilation, diagnosed between Jan 17, 2020, and Feb 13, 2020. Patients, diagnosed after Jan 17, 2020, were given oral arbidol and LPV/r in the combination group and oral LPV/r only in the monotherapy group for 5–21 days. The primary endpoint was a negative conversion rate of coronavirus from the date of COVID-19 diagnosis(day7, day14), and assessed whether the pneumonia was progressing or improving by chest CT (day7).

Results

We analyzed 16 patients who received oral arbidol and LPV/r in the combination group and 17 who oral LPV/r only in the monotherapy group, and both initiated after diagnosis. Baseline clinical, laboratory, and chest CT characteristics were similar between groups. The SARS-CoV-2 could not be detected for 12(75%) of 16 patients’ nasopharyngeal specimens in the combination group after seven days, compared with 6 (35%) of 17 in the monotherapy group (p < 0·05). After 14 days, 15 (94%) of 16 and 9 (52·9%) of 17, respectively, SARS-CoV-2 could not be detected (p < 0·05). The chest CT scans were improving for 11(69%) of 16 patients in the combination group after seven days, compared with 5(29%) of 17 in the monotherapy group (p < 0·05).

Conclusion

In patients with COVID-19, the apparent favorable clinical response with arbidol and LPV/r supports further LPV/r only.

Clinical efficacy of umifenovir in influenza and ARVI (study ARBITR)

AIM

The aim of the study is to obtain additional data on safety and therapeutic efficacy of the antiviral drug Arbidol (umifenovir) in patients with a diagnosis of influenza and common cold.

MATERIALS AND METHODS

Double-blind, randomized, placebo-controlled clinical study investigating efficacy and safety of Arbidol (umifenovir) in Treatment and Prophylaxis of Influenza and Common Cold (ARBITR) IV phase started in November 2011 and completed in April 2016 on the basis of 15 research centers in various regions of the Russian Federation. A total of 359 patients, aged 18 to 65 years with influenza or acute respiratory tract infection, of no more than 36 hours' duration were enrolled in the study. Patients were randomized into two groups: a group of patients (therapy group) treated by Arbidol (umifenovir) at a dosage of 800 mg/day (2 capsules) for 5 days (n=181), and a group of patients receiving placebo 4 times a day for 5 days (n=178). The primary outcome measures of the study were the duration of clinical illness among patients with common cold and influenza/ARVI, the duration and severity of the main symptoms. Number of clinical complications associated with influenza and common cold was assessed as a secondary outcome. Safety was assessed by analyzing number of adverse events that are probably or definitely related to Arbidol, assessing vital signs, examining the physical condition of patients and general clinical laboratory parameters.

RESULTS

In the group treated by umifenovir, the number of full recover patients on the 4th day from the disease onset were significantly differed from the number of such cases in the placebo group. The number of cases of complete recovery after 96 hours was 98 patients (54.1%) and 77 (43.3%), p&lt;0.05, and after 108 hours - 117 (64.6%) and 98 (55.1%), p&lt;0.05. Duration of intoxication was reduced with umifenovir compared to placebo, amounted to 77.76 and 88.91 hours, respectively, p=0.013. The duration of all intoxication syndrome symptoms was also lower in the group receiving umifenovir. Thus, in the therapy group and placebo group, these parameters were respectively: fever duration - 67.96 and 75.32 hours (p=0.037), muscle pain - 52.23 and 59.08 hours (p=0.023), headache - 52.78 and 63.28 hours (p=0.013), weakness - 76.90 and 88.89 hours (p=0.008). The incidence of complications in the umifenovir group was 3.8%, in the placebo group 5.62%. Cases of acute tracheobronchitis was an increase in the placebo group (p&lt;0.02). Umifenovir and placebo were well tolerated. A total of 42 cases of adverse events were registered in 11 patients in the treatment group and in 18 patients in the placebo group, which were not associated with umifenovir or placebo.

CONCLUSION

The results of this study indicate umifenovir safety and confirm its effectiveness to the treatment of influenza and other acute respiratory viral infections in adult patients. It was found that effect of umifenovir in the treatment of influenza in adults is most pronounced in the acute stage of the disease and appears in the reduction of time to resolution of all symptoms of the disease, reducing the severity of symptoms of the disease.

Identification of Compounds Targeting Hepatitis B Virus Core Protein Dimerization through a Split Luciferase Complementation Assay

The capsid of the hepatitis B virus is an attractive antiviral target for developing therapies against chronic hepatitis B infection. Currently available core protein allosteric modulators (CpAMs) mainly affect one of the two major types of protein-protein interactions involved in the process of capsid assembly, namely, the interaction between the core dimers. Compounds targeting the interaction between two core monomers have not been rigorously screened due to the lack of screening models. We report here a cell-based assay in which the formation of core dimers is indicated by split luciferase complementation (SLC). Making use of this model, 2 compounds, Arbidol (umifenovir) and 20-deoxyingenol, were identified from a library containing 672 compounds as core dimerization regulators. Arbidol and 20-deoxyingenol inhibit the hepatitis B virus (HBV) DNA replication in vitro by decreasing and increasing the formation of core dimer and capsid, respectively. Our results provided a proof of concept for the cell model to be used to screen new agents targeting the step of core dimer and capsid formation.

[Time course of changes in cytokines (IFN-γ, IFN-α, IL-18, TNF-α) in the treatment of moderate influenza A (H1N1) pdm09 (2013-2016) with oseltamivir (Tamiflu) and umifenovir (Arbidol) alone and in combination with Kagocel]

AIM

To assess correlation of cytokines levels and therapy regimes a relationship of the time course of changes in the cytokines IFN-γ, IFN-α, IL-18, and TNF-α to the treatment option for influenza A (H1N1) pdm09 with umifenovir (Arbidol) 800 mg/day for 5 days (n=50); oseltamivir (Tamiflu) 150 mg/day for 5 days (n=50); umifenovir (Arbidol) 800 mg/day for 5 days in combination with Kagocel 72 mg/day for 2 days.; 36 mg/day for 2 days (n=50); oseltamivir (Tamiflu) (150 mg/day for 5 days) in combination with Kagocel 72 mg/day for 2 days; 36 mg/day for 2 days (n=50). A comparison group consisted of 30 healthy volunteers.

MATERIAL AND METHODS

The state of immunologic reactivity was assessed twice: at admission of the patients to an infectious disease clinic (at 1-3 disease days) and in the early convalescent period (at 7-8 disease days): venous blood samples were collected to determine the concentrations of IFN-γ, IFN-α, IL-18, and TNF-α by a solid-phase enzyme immunoassay.

RESULTS

All the patients in the acute phase of influenza A showed a statistically significant increase in the levels of IFN-γ, IFN-α, and IL-18 as compared with the control group. The groups receiving monotherapy in the early convalescent period had a decrease in the IFN-γ, IFN-α, and IL-18 concentrations that could be compensated by the combined use of the immunomodulator Kagocel. No statistically significant changes in the levels of TNF-α were found in the patients of all the groups, but the groups receiving monotherapy exhibited its lower concentrations in the convalescence period.

CONCLUSION

The combination of etiotropic antiviral drugs with Kagocel enhances the efficiency of antiviral therapy. Monitoring of antiviral cytokines during the treatment of influenza A is a convenient tool to verify the efficiency of antiviral therapy and needs to be more widely introduced into medical practice.

Structure-based optimization and synthesis of antiviral drug Arbidol analogues with significantly improved affinity to influenza hemagglutinin

Influenza is a highly contagious respiratory viral infection responsible for up to 50,000 deaths per annum in the US alone. The need for new therapeutics with novel modes of action is of paramount importance. We determined the X-ray structure of Arbidol with influenza hemagglutinin and found it was located in a distinct binding pocket. Herein, we report a structure-activity relationship study based on the co-complex combined with bio-layer interferometry to assess the binding of our compounds. Addition of a meta-hydroxy group to the thiophenol moiety of Arbidol to replace a structured water molecule in the binding pocket resulted in a dramatic increase in affinity against both H3 (1150-fold) and H1 (98-fold) hemagglutinin subtypes. Our analogues represent novel leads to yield more potent compounds against hemagglutinin that block viral entry.

Structural basis of influenza virus fusion inhibition by the antiviral drug Arbidol

The broad-spectrum antiviral drug Arbidol shows efficacy against influenza viruses by targeting the hemagglutinin (HA) fusion machinery. However, the structural basis of the mechanism underlying fusion inhibition by Arbidol has remained obscure, thereby hindering its further development as a specific and optimized influenza therapeutic. We determined crystal structures of Arbidol in complex with influenza virus HA from pandemic 1968 H3N2 and recent 2013 H7N9 viruses. Arbidol binds in a hydrophobic cavity in the HA trimer stem at the interface between two protomers. This cavity is distal to the conserved epitope targeted by broadly neutralizing stem antibodies and is ∼16 Å from the fusion peptide. Arbidol primarily makes hydrophobic interactions with the binding site but also induces some conformational rearrangements to form a network of inter- and intraprotomer salt bridges. By functioning as molecular glue, Arbidol stabilizes the prefusion conformation of HA that inhibits the large conformational rearrangements associated with membrane fusion in the low pH of the endosome. This unique binding mode compared with the small-molecule inhibitors of other class I fusion proteins enhances our understanding of how small molecules can function as fusion inhibitors and guides the development of broad-spectrum therapeutics against influenza virus.

The Location of the Protonated and Unprotonated Forms of Arbidol in the Membrane: A Molecular Dynamics Study

Abstract

Arbidol is a potent broad-spectrum antiviral molecule for the treatment and prophylaxis of many viral infections. Viruses that can be inhibited by arbidol include enveloped and non-enveloped viruses, RNA and DNA viruses, as well as pH-independent and pH-dependent ones. These differences in viral types highlight the broad spectrum of Arb antiviral activity and, therefore, it must affect a common viral critical step. Arbidol incorporates rapidly into biological membranes, and some of its antiviral effects might be related to its capacity to interact with and locate into the membrane. However, no information is available of the molecular basis of its antiviral mechanism/s. We have aimed to locate the protonated (Arp) and unprotonated (Arb) forms of arbidol in a model membrane system. Both Arb and Arp locate in between the hydrocarbon acyl chains of the phospholipids but its specific location and molecular interactions differ from each other. Whereas both Arb and Arp average location in the membrane palisade is a similar one, Arb tends to be perpendicular to the membrane surface, whereas Arp tends to be parallel to it. Furthermore, Arp, in contrast to Arb, seems to interact stronger with POPG than with POPC, implying the existence of a specific interaction between Arp, the protonated from, with negatively charged phospholipids. This data would suggest that the active molecule of arbidol in the membrane is the protonated one, i.e., the positively charged molecule. The broad antiviral activity of arbidol would be defined by the perturbation it exerts on membrane structure and therefore membrane functioning.

Graphical Abstract

Electronic supplementary material

The online version of this article (doi:10.1007/s00232-016-9876-3) contains supplementary material, which is available to authorized users.

Antiviral Strategies Against Chikungunya Virus

In the last few decades the Chikungunya virus (CHIKV) has evolved from a geographically isolated pathogen to a virus that is widespread in many parts of Africa, Asia and recently also in Central- and South-America. Although CHIKV infections are rarely fatal, the disease can evolve into a chronic stage, which is characterized by persisting polyarthralgia and joint stiffness. This chronic CHIKV infection can severely incapacitate patients for weeks up to several years after the initial infection. Despite the burden of CHIKV infections, no vaccine or antivirals are available yet. The current therapy is therefore only symptomatic and consists of the administration of analgesics, antipyretics, and anti-inflammatory agents. Recently several molecules with various viral or host targets have been identified as CHIKV inhibitors. In this chapter, we summarize the current status of the development of antiviral strategies against CHIKV infections.

Towards antivirals against chikungunya virus

Chikungunya virus (CHIKV) has re-emerged in recent decades, causing major outbreaks of chikungunya fever in many parts of Africa and Asia, and since the end of 2013 also in Central and South America. Infections are usually associated with a low mortality rate, but can proceed into a painful chronic stage, during which patients may suffer from polyarthralgia and joint stiffness for weeks and even several years. There are no vaccines or antiviral drugs available for the prevention or treatment of CHIKV infections. Current therapy therefore consists solely of the administration of analgesics, antipyretics and anti-inflammatory agents to relieve symptoms. We here review molecules that have been reported to inhibit CHIKV replication, either as direct-acting antivirals, host-targeting drugs or those that act via a yet unknown mechanism. This article forms part of a symposium in Antiviral Research on "Chikungunya discovers the New World."

Arbidol as a broad-spectrum antiviral: an update

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Arbidol (ARB) is licensed in Russia and China for the treatment of influenza and other viral infections.

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ARB inhibits a large panel of viral pathogens, enveloped or not.

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ARB displays a dual binding activity to lipid membranes and to viral or cellular proteins.

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It blocks viral endocytosis and replication in membranous intracellular compartments.

Arbidol (ARB) is a Russian-made small indole-derivative molecule, licensed in Russia and China for prophylaxis and treatment of influenza and other respiratory viral infections. It also demonstrates inhibitory activity against other viruses, enveloped or not, responsible for emerging or globally prevalent infectious diseases such as hepatitis B and C, gastroenteritis, hemorrhagic fevers or encephalitis. In this review, we will explore the possibility and pertinence of ARB as a broad-spectrum antiviral, after a careful examination of its physico-chemical properties, pharmacokinetics, toxicity, and molecular mechanisms of action. Recent studies suggest that ARB’s dual interactions with membranes and aromatic amino acids in proteins may be central to its broad-spectrum antiviral activity. This could impact on the virus itself, and/or on cellular functions or critical steps in virus-cell interactions, thereby positioning ARB as both a direct-acting antiviral (DAA) and a host-targeting agent (HTA). In the context of recent studies in animals and humans, we will discuss the prospective clinical use of ARB in various viral infections.

Arbidol inhibits viral entry by interfering with clathrin-dependent trafficking

Arbidol (ARB) is a broad-spectrum antiviral displaying activity against a number of enveloped and non-enveloped viruses. It was described as a viral entry inhibitor and shown to interact at the molecular level with lipid membranes and viral fusion glycoproteins to impede viral entry and fusion. However its mechanism of action at the cellular level remains unknown. Here, by using live-cell confocal imaging and the hepatitis C virus as a model virus, we show that ARB affects clathrin-mediated endocytosis by impeding dynamin-2-induced membrane scission. Moreover it induces the intracellular accumulation of clathrin-coated structures where viral particles are trapped. Collectively, our results shed light on the mechanistic aspects of ARB antiviral activity and suggest that ARB could prevent cell infection by viruses that enter through clathrin-mediated endocytosis.