A perspective on the applications of furin inhibitors for the treatment of SARS-CoV-2

Repositioning of Furin inhibitors as potential drugs against SARS-CoV-2 through computational approaches

The recent spread of SARS-CoV-2 has led to serious concerns about newly emerging infectious coronaviruses. Drug repurposing is a practical method for rapid development of antiviral agents. The viral spike protein of SARS-CoV-2 binds to its major receptor ACE2 to promote membrane fusion. Following the entry process, the spike protein is further activated by cellular proteases such as TMPRSS2 and Furin to promote viral entry into human cells. A crucial factor in preventing SARS-CoV-2 from entering target cells using HIV-1 fusion inhibitors is the similarity between the fusion mechanisms of SARS-CoV-2 and HIV-1. In this investigation, the HIV-1 fusion inhibitors CMK, Luteolin, and Naphthofluorescein were selected to understand the molecular mode of interactions and binding energy of Furin with these experimental inhibitors. The binding affinity of the three inhibitors with Furin was verified by molecular docking studies. The docking scores of CMK, Luteolin and Naphthofluorescein are -7.4 kcal/mol, -9.3 kcal/mol, and -10.7 kcal/mol, respectively. Therefore, these compounds were subjected to MD, drug-likeness, ADMET, and MM-PBSA analysis. According to the results of a 200 ns MD simulation, all tested compounds show stability with the complex and can be employed as promising inhibitors targeting SARS-CoV-2 Furin protease. In addition, pharmacokinetic analysis revealed that these compounds possess favorable drug-likeness properties. Thus, this study of Furin inhibitors helps in the evaluation of these compounds for use as novel drugs against SARS-CoV-2.

The dual actions of miRNA16a in restricting Bovine Coronavirus replication through downregulation of Furin and enhancing the host immune response

The roles of host cell miRNAs have not been well studied in the context of BCoV replication and immune regulation. This study aimed to identify miRNA candidates that regulate essential host genes involved in BCoV replication, tissue tropism, and immune regulation. To achieve these goals, we used two isolates of BCoV (enteric and respiratory) to infect bovine endothelial cells (BECs) and Madine Darby Bovine Kidney (MDBK) cells. We determined the miRNA expression profiles of these cells after BCoV infection. The expression of miRNA16a is differentially altered during BCoV infection. Our data show that miRNA16a is a significantly downregulated miRNA in both in vitro and ex vivo models. We confirmed the miRNA16aexpression profile by qRT-PCR. Overexpression of pre-miRNA16ain the BEC and the MDBK cell lines markedly inhibited BCoV infection, as determined by the viral genome copy numbers measured by qRT‒PCR, viral protein expression (S and N) measured by Western blot, and virus infectivity using a plaque assay. Our bioinformatic prediction showed that Furin is a potential target of miRNA16a. We compared the Furin protein expression level in pre-miRNA16a-transfected/BCoV-infected cells to that in pre-miRNA-scrambled-transfected cells. Our qRT-PCR and Western blot data revealed marked inhibition of Furin expression at the mRNA and protein levels, respectively. BCoV-S protein expression was markedly inhibited at both the mRNA and protein levels. To further confirm the impact of the downregulation of the Furin enzyme on the replication of BCoV, we transfected cells with specific Furin-siRNAs parallel to the scrambled siRNA. Marked inhibition of BCoV replication was observed in the Furin-siRNA-treated group. To further validate Furin as a novel target for miRNA16a, we cloned the 3'UTR of bovine Furin carrying the seed region of miRNA16a in the dual luciferase vector. Our data showed that luciferase activity in pre-miRNA16a-transfected cells decreased by more than 50% compared to cells transfected with the construct carrying the mutated Furin seed region. Our data confirmed that miRNA16ainhibits BCoV replication by targeting the host cell line Furin and the BCoV-S glycoprotein. It also enhances the host immune response, which contributes to the inhibition of viral replication. This is the first study to confirm that Furin is a valid target of miRNA16a. Our findings highlight the clinical applications of host miRNA16a as a potential miRNA-based vaccine/antiviral therapy.

Impact of genetic variations of gene involved in regulation of metabolism, inflammation and coagulation on pathogenesis of cardiac injuries associated with COVID-19

BACKGROUND

SARS-CoV-2 infection can result in long-term chronic cardiovascular (CV) damage after the acute phase of the illness. COVID-19 frequently causes active myocarditis, SARS-CoV-2 can directly infect and kill cardiac cells, causing severe pathology and dysfunction across the organs and cells. Till now, the pathogenesis of COVID-19-associated cardiac injuries has not been understood, but there are several factors that contribute to the progression of cardiac injuries, such as genetic, dietary, and environmental. Among them ranges of host genetic factor including metabolizing, inflammation, and coagulation related genes have a role to contribute the cardiac injuries induced by COVID-19. Hereditary DNA sequence variations contribute to the risk of illness in almost all of these diseases. Hence, we comprehended the occurrence of genetic variations of metabolizing, inflammation and coagulation-related genes in the general population, their expression in various diseases, and their impact on cardiac injuries induced by COVID-19.

METHOD

We utilized multiple databases, including PubMed (Medline), EMBASE, and Google Scholar, for literature searches.

DESCRIPTION

The genes involved in metabolism (APOE, MTHFR), coagulation (PAI-1, ACE2), and immune factors (CRP, ESR, and troponin I) may have a role in the progression of COVID-19-associated cardiac injuries. The risk factors for CVD are significantly varied between and within different regions. In healthy individuals, the ACE I allele is responsible for the predisposition to CAD, but the ACE D haplotype is responsible for susceptibility and severity, which ultimately leads to heart failure. Patients who carry the T allele of rs12329760 in the TMPRSS2 gene are at risk for developing the severe form of COVID-19. IL-6 (rs1800796/rs1800795) polymorphism is associated with an increased mortality rate and susceptibility to severe COVID-19 disease. While the putative role of IL-6 associated with chronic, inflammatory diseases like cardiac and cerebrovascular disease is well known.

CONCLUSION

The occurrence of genetic variations in the ACE-2, AGT, DPP-IV, TMPRSS2, FUIRN, IL-4, IL-6, IFN-γ, and CYP2D6 genes is varied among different populations. Examining the correlation between these variations and their protein levels and cardiac injuries induced by COVID-19 may provide valuable insights into the pathogenesis of cardiac injuries induced by COVID-19.

In Vitro Evaluation of Antipseudomonal Activity and Safety Profile of Peptidomimetic Furin Inhibitors

Inhibitors of the serine protease furin have been widely studied as antimicrobial agents due to their ability to block the cleavage and activation of certain viral surface proteins and bacterial toxins. In this study, the antipseudomonal effects and safety profiles of the furin inhibitors MI-1851 and MI-2415 were assessed. Fluorescence quenching studies suggested no relevant binding of the compounds to human serum albumin and α1-acid glycoprotein. Both inhibitors demonstrated significant antipseudomonal activity in Madin-Darby canine kidney cells, especially compound MI-1851 at very low concentrations (0.5 µM). Using non-tumorigenic porcine IPEC-J2 cells, neither of the two furin inhibitors induced cytotoxicity (CCK-8 assay) or altered significantly the intracellular (Amplex Red assay) or extracellular (DCFH-DA assay) redox status even at a concentration of 100 µM. The same assays with MI-2415 conducted on primary human hepatocytes also resulted in no changes in cell viability and oxidative stress at up to 100 µM. Microsomal and hepatocyte-based CYP3A4 activity assays showed that both inhibitors exhibited a concentration-dependent inhibition of the isoenzyme at high concentrations. In conclusion, this study indicates a good safety profile of the furin inhibitors MI-1851 and MI-2415, suggesting their applicability as antimicrobials for further in vivo investigations, despite some inhibitory effects on CYP3A4.

Ethyl acetate extract of fungus comb from Malayan termite (Macrotermes gilvus Hagen) mound modulates splenic inflammatory responses in mice

Background

The fungus comb is a unique structure inside termites' nests that facilitates the growth of Termitomyces sp. as a nutrient source for the termites. It is known to possess immunomodulatory properties that boost the immune system.

Aim

The objective of this study was to assess the impact of ethyl acetate extract of fungus comb (EAEFC) on the inflammatory reaction in the spleen of mice induced by intraperitoneal injection of lipopolysaccharide (LPS).

Methods

An experimental study was conducted using a post-test-only control group design with male BALB/C mice (n = 24). The mice were divided randomly into four groups, each comprising six mice, and administered substances via gavage. Groups I and III were administered a solution of 5% dimethyl sulfoxide (DMSO) in distilled water, while Groups II and IV were given 500 mg/kg BW EAEFC dissolved in 5% DMSO. On the fifteenth day, Groups I and II received intraperitoneal injections of 5 ml/kg BW saline, while Groups III and IV were injected with 10 mg/kg BW LPS dissolved in saline. After three hours, the mice were euthanized and splenic immunohistology was examined under a light microscope. The results were expressed as mean ± standard deviation, while the group differences were assessed statistically.

Results

The expression of interleukin (IL)-1, furin, and activated NK cell was significantly higher in the inflamed model after EAEFC supplementation, while the extract suppressed IL-10.

Conclusion

EAEFC was found to alter cytokine expression in the spleen in response to inflammation.

The Role of Furin and Its Therapeutic Potential in Cardiovascular Disease Risk

Furin is an important proteolytic enzyme, converting several proteins from inactive precursors to their active forms. Recently, proteo-genomic analyses in European and East Asian populations suggested a causal association of furin with ischaemic heart disease, and there is growing interest in its role in cardiovascular disease (CVD) aetiology. In this narrative review, we present a critical appraisal of evidence from population studies to assess furin's role in CVD risk and potential as a drug target for CVD. Whilst most observational studies report positive associations between furin expression and CVD risk, some studies report opposing effects, which may reflect the complex biological roles of furin and its substrates. Genetic variation in FURIN is also associated with CVD and its risk factors. We found no evidence of current clinical development of furin as a drug target for CVD, although several phase 1 and 2 clinical trials of furin inhibitors as a type of cancer immunotherapy have been completed. The growing field of proteo-genomics in large-scale population studies may inform the future development of furin and other potential drug targets to improve the treatment and prevention of CVD.

Development and Prospects of Furin Inhibitors for Therapeutic Applications

Furin, a serine protease enzyme located in the Golgi apparatus of animal cells, plays a crucial role in cleaving precursor proteins into their mature, active forms. It is ubiquitously expressed across various tissues, including the brain, lungs, gastrointestinal tract, liver, pancreas, and reproductive organs. Since its discovery in 1990, furin has been recognized as a significant therapeutic target, leading to the active development of furin inhibitors for potential use in antiviral, antibacterial, anticancer, and other therapeutic applications. This review provides a comprehensive overview of the progress in the development and characterization of furin inhibitors, encompassing peptides, linear and macrocyclic peptidomimetics, and non-peptide compounds, highlighting their potential in the treatment of both infectious and non-infectious diseases.

Evaluation of Potential Furin Protease Inhibitory Properties of Pioglitazone, Rosiglitazone, and Pirfenidone: An In Silico Docking and Molecular Dynamics Simulation Approach

Furin (Fur) is a member of the protease convertase family; its expression is crucial for cleaving and maturing many proteins. Fur also represents a therapeutic target in cancer, autoimmune diseases, and viral infections. Pioglitazone (PGZ) and rosiglitazone (RGZ) are thiazolidinediones prescribed to type 2 diabetes patients and are structurally similar to the known Fur inhibitors naphthofluorescein (NPF) and pirfenidone (PFD). Thus, this study used molecular docking and molecular dynamics to assess and compare the affinities and the molecular interactions of these four ligands with the Fur active site (FurAct) and the recently described Fur allosteric site (FurAll). The 7QXZ Fur structure was used for molecular dockings, and for the best pose complexes, molecular dynamics were run for 100 ns. The best affinities of the ligand/FurAct and ligand/FurAll complexes were with NPF, PGZ, and RGZ, while PFD presented the lowest affinity. Asp154 was the central residue involved in FurAct complex formation, while Glu488 and Asn310 were the central residues involved in FurAll complex formation. This study shows the potential of RGZ, PGZ, and PFD as Fur competitive (FurAct) and non-competitive (FurAll) inhibitors. Therefore, they are candidates for repurposing in response to future emerging diseases through the modulation of Fur activity.

Structure-based virtual screening methods for the identification of novel phytochemical inhibitors targeting furin protease for the management of COVID-19

The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, is a highly contagious respiratory disease with widespread societal impact. The symptoms range from cough, fever, and pneumonia to complications affecting various organs, including the heart, kidneys, and nervous system. Despite various ongoing efforts, no effective drug has been developed to stop the spread of the virus. Although various types of medications used to treat bacterial and viral diseases have previously been employed to treat COVID-19 patients, their side effects have also been observed. The way SARS-CoV-2 infects the human body is very specific, as its spike protein plays an important role. The S subunit of virus spike protein cleaved by human proteases, such as furin protein, is an initial and important step for its internalization into a human host. Keeping this context, we attempted to inhibit the furin using phytochemicals that could produce minimal side effects. For this, we screened 408 natural phytochemicals from various plants having antiviral properties, against furin protein, and molecular docking and dynamics simulations were performed. Based on the binding score, the top three compounds (robustaflavone, withanolide, and amentoflavone) were selected for further validation. MM/GBSA energy calculations revealed that withanolide has the lowest binding energy of -57.2 kcal/mol followed by robustaflavone and amentoflavone with a binding energy of -45.2 kcal/mol and -39.68 kcal/mol, respectively. Additionally, ADME analysis showed drug-like properties for these three lead compounds. Hence, these natural compounds robustaflavone, withanolide, and amentoflavone, may have therapeutic potential for the management of SARS-CoV-2 by targeting furin.

Role of marine natural products in the development of antiviral agents against SARS-CoV-2: potential and prospects

A novel coronavirus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has surfaced and caused global concern owing to its ferocity. SARS-CoV-2 is the causative agent of coronavirus disease 2019; however, it was only discovered at the end of the year and was considered a pandemic by the World Health Organization. Therefore, the development of novel potent inhibitors against SARS-CoV-2 and future outbreaks is urgently required. Numerous naturally occurring bioactive substances have been studied in the clinical setting for diverse disorders. The intricate infection and replication mechanism of SARS-CoV-2 offers diverse therapeutic drug targets for developing antiviral medicines by employing natural products that are safer than synthetic compounds. Marine natural products (MNPs) have received increased attention in the development of novel drugs owing to their high diversity and availability. Therefore, this review article investigates the infection and replication mechanisms, including the function of the SARS-CoV-2 genome and structure. Furthermore, we highlighted anti-SARS-CoV-2 therapeutic intervention efforts utilizing MNPs and predicted SARS-CoV-2 inhibitor design.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-023-00215-9.

SARS-CoV-2 Spike Protein Is Capable of Inducing Cell-Cell Fusions Independent from Its Receptor ACE2 and This Activity Can Be Impaired by Furin Inhibitors or a Subset of Monoclonal Antibodies

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was responsible for the COVID-19 pandemic, efficiently spreads cell-to-cell through mechanisms facilitated by its membrane glycoprotein spike. We established a dual split protein (DSP) assay based on the complementation of GFP and luciferase to quantify the fusogenic activity of the SARS-CoV-2 spike protein. We provide several lines of evidence that the spike protein of SARS-CoV-2, but not SARS-CoV-1, induced cell-cell fusion even in the absence of its receptor, angiotensin-converting enzyme 2 (ACE2). This poorly described ACE2-independent cell fusion activity of the spike protein was strictly dependent on the proteasomal cleavage of the spike by furin while TMPRSS2 was dispensable. Previous and current variants of concern (VOCs) differed significantly in their fusogenicity. The Delta spike was extremely potent compared to Alpha, Beta, Gamma and Kappa, while the Omicron spike was almost devoid of receptor-independent fusion activity. Nonetheless, for all analyzed variants, cell fusion was dependent on furin cleavage and could be pharmacologically inhibited with CMK. Mapping studies revealed that amino acids 652-1273 conferred the ACE2-independent fusion activity of the spike. Unexpectedly, residues proximal to the furin cleavage site were not of major relevance, whereas residue 655 critically regulated fusion. Finally, we found that the spike's fusion activity in the absence of ACE2 could be inhibited by antibodies directed against its N-terminal domain (NTD) but not by antibodies targeting its receptor-binding domain (RBD). In conclusion, our BSL-1-compatible DSP assay allowed us to screen for inhibitors or antibodies that interfere with the spike's fusogenic activity and may therefore contribute to both rational vaccine design and development of novel treatment options against SARS-CoV-2.

Repurposing clinically available drugs and therapies for pathogenic targets to combat SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic has affected a large portion of the global population, both physically and mentally. Current evidence suggests that the rapidly evolving coronavirus subvariants risk rendering vaccines and antibodies ineffective due to their potential to evade existing immunity, with enhanced transmission activity and higher reinfection rates that could lead to new outbreaks across the globe. The goal of viral management is to disrupt the viral life cycle as well as to relieve severe symptoms such as lung damage, cytokine storm, and organ failure. In the fight against viruses, the combination of viral genome sequencing, elucidation of the structure of viral proteins, and identifying proteins that are highly conserved across multiple coronaviruses has revealed many potential molecular targets. In addition, the time- and cost-effective repurposing of preexisting antiviral drugs or approved/clinical drugs for these targets offers considerable clinical advantages for COVID-19 patients. This review provides a comprehensive overview of various identified pathogenic targets and pathways as well as corresponding repurposed approved/clinical drugs and their potential against COVID-19. These findings provide new insight into the discovery of novel therapeutic strategies that could be applied to the control of disease symptoms emanating from evolving SARS-CoV-2 variants.

Protein structure-based in-silico approaches to drug discovery: Guide to COVID-19 therapeutics

With more than 5 million fatalities and close to 300 million reported cases, COVID-19 is the first documented pandemic due to a coronavirus that continues to be a major health challenge. Despite being rapid, uncontrollable, and highly infectious in its spread, it also created incentives for technology development and redefined public health needs and research agendas to fast-track innovations to be translated. Breakthroughs in computational biology peaked during the pandemic with renewed attention to making all cutting-edge technology deliver agents to combat the disease. The demand to develop effective treatments yielded surprising collaborations from previously segregated fields of science and technology. The long-standing pharmaceutical industry's aversion to repurposing existing drugs due to a lack of exponential financial gain was overrun by the health crisis and pressures created by front-line researchers and providers. Effective vaccine development even at an unprecedented pace took more than a year to develop and commence trials. Now the emergence of variants and waning protections during the booster shots is resulting in breakthrough infections that continue to strain health care systems. As of now, every protein of SARS-CoV-2 has been structurally characterized and related host pathways have been extensively mapped out. The research community has addressed the druggability of a multitude of possible targets. This has been made possible due to existing technology for virtual computer-assisted drug development as well as new tools and technologies such as artificial intelligence to deliver new leads. Here in this article, we are discussing advances in the drug discovery field related to target-based drug discovery and exploring the implications of known target-specific agents on COVID-19 therapeutic management. The current scenario calls for more personalized medicine efforts and stratifying patient populations early on for their need for different combinations of prognosis-specific therapeutics. We intend to highlight target hotspots and their potential agents, with the ultimate goal of using rational design of new therapeutics to not only end this pandemic but also uncover a generalizable platform for use in future pandemics.

Proprotein convertases regulate trafficking and maturation of key proteins within the secretory pathway

Proprotein Convertases (PCs) are serine endoproteases that regulate the homeostasis of protein substrates in the cell. The PCs family counts 9 members-PC1/3, PC2, PC4, PACE4, PC5/6, PC7, Furin, SKI-1/S1P, and PCSK9. The first seven PCs are known as Basic Proprotein Convertases due to their propensity to cleave after polybasic clusters. SKI-1/S1P requires the additional presence of hydrophobic residues for processing, whereas PCSK9 is catalytically dead after autoactivation and exerts its functions using mechanisms alternative to direct cleavage. All PCs traffic through the canonical secretory pathway, reaching different compartments where the various substrates reside. Despite PCs members do not share the same subcellular localization, most of the cellular organelles count one or more Proprotein Convertases, including ER, Golgi stack, endosomes, secretory granules, and plasma membranes. The widespread expression of these enzymes at the systemic level speaks for their importance in the homeostasis of a large number of biological functions. Among others, PCs cleave precursors of hormones and growth factors and activate receptors and transcription factors. Notably, dysregulation of the enzymatic activity of Proprotein Convertases is associated to major human pathologies, such as cardiovascular diseases, cancer, diabetes, infections, inflammation, autoimmunity diseases, and Parkinson. In the current COVID-19 pandemic, Furin has further attracted the attention as a key player for conferring high pathogenicity to SARS-CoV-2. Here, we review the Proprotein Convertases family and their most important substrates along the secretory pathway. Knowledge about the complex functions of PCs is important to identify potential drug strategies targeting this class of enzymes.

In vitro inhibition of SARS-CoV-2 Infection by dry algae powders

Chlorella spp., Spirulina spp., and fucoidan dry powders, are commercialized as food supplements and are considered safe for human consumption. Their broad-spectrum antiviral properties have been studied, however, their effect against SARS-CoV-2 remains unknown. We investigated the potential antiviral activity of three algae powders: Chlorella vulgaris, Arthrospira maxima (Spirulina) and fucoidan purified from marine brown algae Sargassum spp. against SARS-CoV-2 infection in vitro. Vero cells were incubated with 70 μg/ml of each algae powder and either 50 or 100 TCID₅₀/ml of SARS-CoV-2, in two types of experiments (pretreatment and simultaneous) and comparing two kinds of solvents (DMEM and DMSO). Chlorella vulgaris powder, inhibited SARS-CoV-2 infection in all assays; viral RNA was significantly reduced in supernatants at 24, 48, 72, and 96 h post-infection, the highest difference in viral load (8000-fold) was observed after 96 h. Arthrospira maxima powder inhibited SARS-CoV-2 infection using 50 TCID₅₀/ml for both experimental schemes, but protection percent was lower when viral inoculum was increase to 100 TCID₅₀/ml; viral RNA decreased 48 h after infection, reaching a 250-fold difference at 72 h. Fucoidan powder partially inhibited SARS-CoV-2 infection since no CPE was observed in 62.5% of trated cultures in DMEM, but the antiviral activity was increased to 100% of protection when DMSO was used as solvent. All the algae samples showed high antiviral activity against SARS-CoV-2 with a SI above of 18. These results suggest that all three algae samples are potential therapeutic candidates for the treatment of COVID-19.

Neuronal and Non-Neuronal GABA in COVID-19: Relevance for Psychiatry

Infection with SARS-CoV-2, the causative agent of the COVID-19 pandemic, originated in China and quickly spread across the globe. Despite tremendous economic and healthcare devastation, research on this virus has contributed to a better understanding of numerous molecular pathways, including those involving γ-aminobutyric acid (GABA), that will positively impact medical science, including neuropsychiatry, in the post-pandemic era. SARS-CoV-2 primarily enters the host cells through the renin–angiotensin system’s component named angiotensin-converting enzyme-2 (ACE-2). Among its many functions, this protein upregulates GABA, protecting not only the central nervous system but also the endothelia, the pancreas, and the gut microbiota. SARS-CoV-2 binding to ACE-2 usurps the neuronal and non-neuronal GABAergic systems, contributing to the high comorbidity of neuropsychiatric illness with gut dysbiosis and endothelial and metabolic dysfunctions. In this perspective article, we take a closer look at the pathology emerging from the viral hijacking of non-neuronal GABA and summarize potential interventions for restoring these systems.

Oral antiviral treatments for COVID-19: opportunities and challenges

The use of antiviral COVID-19 medications can successfully inhibit SARS-CoV-2 replication and prevent disease progression to a more severe form. However, the timing of antiviral treatment plays a crucial role in this regard. Oral antiviral drugs provide an opportunity to manage SARS-CoV-2 infection without a need for hospital admission, easing the general burden that COVID-19 can have on the healthcare system. This review paper (i) presents the potential pharmaceutical antiviral targets, including various host-based targets and viral-based targets, (ii) characterizes the first-generation anti-SARS-CoV-2 oral drugs (nirmatrelvir/ritonavir and molnupiravir), (iii) summarizes the clinical progress of other oral antivirals for use in COVID-19, (iv) discusses ethical issues in such clinical trials and (v) presents challenges associated with the use of oral antivirals in clinical practice. Oral COVID-19 antivirals represent a part of the strategy to adapt to long-term co-existence with SARS-CoV-2 in a manner that prevents healthcare from being overwhelmed. It is pivotal to ensure equal and fair global access to the currently available oral antivirals and those authorized in the future.