Molnupiravir-A Novel Oral Anti-SARS-CoV-2 Agent

An Update on SARS-CoV-2 Clinical Trial Results-What We Can Learn for the Next Pandemic

The coronavirus disease 2019 (COVID-19) pandemic has claimed over 7 million lives worldwide, providing a stark reminder of the importance of pandemic preparedness. Due to the lack of approved antiviral drugs effective against coronaviruses at the start of the pandemic, the world largely relied on repurposed efforts. Here, we summarise results from randomised controlled trials to date, as well as selected in vitro data of directly acting antivirals, host-targeting antivirals, and immunomodulatory drugs. Overall, repurposing efforts evaluating directly acting antivirals targeting other viral families were largely unsuccessful, whereas several immunomodulatory drugs led to clinical improvement in hospitalised patients with severe disease. In addition, accelerated drug discovery efforts during the pandemic progressed to multiple novel directly acting antivirals with clinical efficacy, including small molecule inhibitors and monoclonal antibodies. We argue that large-scale investment is required to prepare for future pandemics; both to develop an arsenal of broad-spectrum antivirals beyond coronaviruses and build worldwide clinical trial networks that can be rapidly utilised.

Effectiveness of Molnupiravir Treatment in Patients with COVID-19 in Korea: A Propensity Score Matched Study

BACKGROUND

The MOVe-OUT (efficacy and safety of molnupiravir [MK-4482] in non-hospitalized adult participants with COVID-19 [MK-4482-002]) trial reported that the administration of molnupiravir in unvaccinated patients with coronavirus disease 2019 (COVID-19) before the Omicron epidemic showed a preventive effect of 31% against hospitalization and death. However, studies on the preventive effect of molnupiravir against progression to severe disease and death in patients with COVID-19 during the Omicron epidemic are limited. This study aimed to evaluate the preventive effect of molnupiravir against severe/critical illness or death and death in Korean patients with COVID-19 who were vaccinated mostly during the Omicron epidemic.

MATERIALS AND METHODS

This study used large-scale retrospective cohort data to select patients with COVID-19 who were either treated or not treated with molnupiravir, between August 2022 and March 2023, at a ratio of 1 : 4 using the propensity score matching method. In total, 762,768 patients comprised the non- administered group, and 190,692 patients comprised the molnupiravir-administered group. The preventive effect of molnupiravir against severe/critical illness or death and death was analyzed using logistic regression analysis.

RESULTS

The preventive effect of molnupiravir against severe/critical illness or death and death, represented by the odds ratio (OR) and 95% confidence interval (CI), in the molnupiravir-administered and non-administered group was (OR: 0.714; CI: 0.667 - 0.764) and (OR: 0.749; CI: 0.682 - 0.823), respectively. As age increased, the preventive effect against severe/critical illness or death and death increased. The preventive effect against severe/critical illness or death at ≥60 years was (OR: 0.669; CI: 0.624 - 0.717), at ≥70 years was (OR: 0.614; CI: 0.570 - 0.661), and at ≥80 years was (OR: 0.563; CI: 0.515 - 0.615). The preventive effect against death at ≥60 years was (OR: 0.729; CI: 0.663 - 0.802), at ≥70 years was (OR: 0.676; CI: 0.612 - 0.747), and at ≥80 years was (OR: 0.622; CI: 0.554 - 0.698).

CONCLUSION

Although molnupiravir showed a relatively weak preventive effect against severe/critical illness or death (29%) and death (25%) among patients with COVID-19, it exhibited a stronger protective effect in older patients than in younger patients. In particular, the preventive effect against severe/critical illness or death (44%) and death (38%) in those aged ≥80 years was pronounced. This study strongly suggests that molnupiravir administration can alleviate the burden on the medical system, and treat patients with COVID-19 effectively by reducing its progression to severe disease and death.

An active metabolite of the anti-COVID-19 drug molnupiravir impairs mouse preimplantation embryos at clinically relevant concentrations

Molnupiravir is a nucleoside analog antiviral that is authorized for use in the treatment of COVID-19. For its therapeutic action, molnupiravir is converted after ingestion to the active metabolite N4-hydroxycytidine, which is incorporated into the viral genome to cause lethal mutagenesis. Molnupiravir is not recommended for use during pregnancy, because preclinical animal studies suggest that it is hazardous to developing embryos. However, the mechanisms underlying the embryotoxicity of molnupiravir are currently unknown. To gain mechanistic insights into its embryotoxic action, the effects of molnupiravir and N4-hydroxycytidine were examined on the in vitro development of mouse preimplantation embryos. Molnupiravir did not prevent blastocyst formation even at concentrations that were much higher than the therapeutic plasma levels. By contrast, N4-hyroxycytidine exhibited potent toxicity, as it interfered with blastocyst formation and caused extensive cell death at concentrations below the therapeutic plasma levels. The adverse effects of N4-hydroxycytidine were dependent on the timing of exposure, such that treatment after the 8-cell stage, but not before it, caused embryotoxicity. Transcriptomic analysis of N4-hydroxycytidine-exposed embryos, together with the examination of eIF-2a protein phosphorylation level, suggested that N4-hydroxycytidine induced the integrated stress response. The adverse effects of N4-hydroxycytidine were significantly alleviated by the co-treatment with S-(4-nitrobenzyl)-6-thioinosine, suggesting that the embryotoxic potential of N4-hydroxycytidine requires the activity of nucleoside transporters. These findings show that the active metabolite of molnupiravir impairs preimplantation development at clinically relevant concentrations, providing mechanistic foundation for further studies on the embryotoxic potential of molnupiravir and other related nucleoside antivirals.

Development and Validation of a High-Performance Liquid Chromatography with Tandem Mass Spectrometry (HPLC-MS/MS) Method for Quantification of Major Molnupiravir Metabolite (β-D-N4-hydroxycytidine) in Human Plasma

Molnupiravir is an antiviral drug against viral RNA polymerase activity approved by the FDA for the treatment of COVID-19, which is metabolized to β-D-N4-hydroxycytidine (NHC) in human blood plasma. A novel method was developed and validated for quantifying NHC in human plasma within the analytical range of 10-10,000 ng/mL using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) to support pharmacokinetics studies. For sample preparation, the method of protein precipitation by acetonitrile was used, with promethazine as an internal standard. Chromatographic separation was carried out on a Shim-pack GWS C18 (150 mm × 4.6 mm, 5 μm) column in a gradient elution mode. A 0.1% formic acid solution in water with 0.08% ammonia solution (eluent A, v/v) and 0.1% formic acid solution in methanol with 0.08% ammonia solution mixed with acetonitrile in a 4:1 ratio (eluent B, v/v) were used as a mobile phase. Electrospray ionization (ESI) was used as an ionization source. The developed method was validated in accordance with the Eurasian Economic Union (EAEU) rules, based on the European Medicines Agency (EMA) and Food and Drug Administration (FDA) guidelines for the following parameters and used within the analytical part of the clinical study of molnupiravir drugs: selectivity, suitability of standard sample, matrix effect, calibration curve, accuracy, precision, recovery, lower limit of quantification (LLOQ), carryover, and stability.

Preferability of Molnupiravir, an Anti-COVID-19 Drug, toward Purine Nucleosides: A Quantum Mechanical Study

Structural aspects of molnupiravir complexed with the RNA of the SARS-CoV-2 virus have been recently resolved inside the RNA-dependent RNA polymerase (RdRp), demonstrating the interactions of molnupiravir with purine nucleosides. However, the preference of molnupiravir to interact with one purine nucleoside over another has not been clearly investigated. Herein, the complexation of molnupiravir in its active form with guanosine and adenosine was compared, using sundry density functional theory calculations. The plausible tautomeric structures of the molnupiravir drug in complex with guanosine/adenosine were minutely scrutinized. The relative energy findings outlined the favorability of amino-molnupiravir···keto-amino-guanosine and imino-molnupiravir···amino-adenosine optimized complexes. According to the interaction (Eint) and binding (Ebind) energy values, higher preferential base-pairing of molnupiravir with guanosine over the adenosine one was recognized with Eint/Ebind values of -31.16/-21.81 and -13.93/-12.83 kcal/mol, respectively. This could be interpreted by the presence of three and two hydrogen bonds within the former and latter complexes, respectively. Observable changes in the electronic properties and global indices of reactivity of the studied complexes also confirmed the preferential binding within the studied complexes. The findings from the quantum theory of atoms in molecules and the noncovalent interaction index also support the partially covalent nature of the investigated interactions. For both complexes, changes in thermodynamic parameters outlined the spontaneous, exothermic, and nonrandom states of the inspected interactions. Inspecting the solvent effect on the studied interactions outlined more observable amelioration within the water medium compared with the gas one. These results would be a durable ground for the forthcoming studies concerned with the interactions of the molnupiravir drug with purine nucleosides.

Combination Therapy with UV-4B and Molnupiravir Enhances SARS-CoV-2 Suppression

The host targeting antiviral, UV-4B, and the RNA polymerase inhibitor, molnupiravir, are two orally available, broad-spectrum antivirals that have demonstrated potent activity against SARS-CoV-2 as monotherapy. In this work, we evaluated the effectiveness of UV-4B and EIDD-1931 (molnupiravir's main circulating metabolite) combination regimens against the SARS-CoV-2 beta, delta, and omicron BA.2 variants in a human lung cell line. Infected ACE2 transfected A549 (ACE2-A549) cells were treated with UV-4B and EIDD-1931 both as monotherapy and in combination. Viral supernatant was sampled on day three when viral titers peaked in the no-treatment control arm, and levels of infectious virus were measured by plaque assay. The drug-drug effect interaction between UV-4B and EIDD-1931 was also defined using the Greco Universal Response Surface Approach (URSA) model. Antiviral evaluations demonstrated that treatment with UV-4B plus EIDD-1931 enhanced antiviral activity against all three variants relative to monotherapy. These results were in accordance with those obtained from the Greco model, as these identified the interaction between UV-4B and EIDD-1931 as additive against the beta and omicron variants and synergistic against the delta variant. Our findings highlight the anti-SARS-CoV-2 potential of UV-4B and EIDD-1931 combination regimens, and present combination therapy as a promising therapeutic strategy against SARS-CoV-2.

Molnupiravir: A Versatile Prodrug against SARS-CoV-2 Variants

The nucleoside analog β-D-N4-hydroxycytidine is the active metabolite of the prodrug molnupiravir and is accepted as an efficient drug against COVID-19. Molnupiravir targets the RNA-dependent RNA polymerase (RdRp) enzyme, which is responsible for replicating the viral genome during the replication process of certain types of viruses. It works by disrupting the normal function of the RdRp enzyme, causing it to make mistakes during the replication of the viral genome. These mistakes can prevent the viral RNA from being transcribed, converted into a complementary DNA template, translated, or converted into a functional protein. By disrupting these crucial steps in the viral replication process, molnupiravir can effectively inhibit the replication of the virus and reduce its ability to cause disease. This review article sheds light on the impact of molnupiravir and its metabolite on SARS-CoV-2 variants of concern, such as delta, omicron, and hybrid/recombinant variants. The detailed mechanism and molecular interactions using molecular docking and dynamics have also been covered. The safety and tolerability of molnupiravir in patients with comorbidities have also been emphasized.

Ritonavir-boosted Nirmatrelvir and COVID-19 outcomes in the age of Omicron variant

Nirmatrelvir boosted with Ritonavir is the recommended and preferred treatment for COVID-19. Because real-world evidence of Nirmatrelvir's antiviral activity against the Omicron variation is minimal, our study focuses on recent papers suggesting the use of Ritonavir-boosted Nirmatrelvir in the real world against the most frequent SARS coronavirus variant circulating worldwide (Omicron). Despite sparse clinical evidence, we discovered that Ritonavir-boosted Nirmatrelvir reduced COVID-19-related hospitalization and mortality during the onset of the Omicron variant. Furthermore, this study discusses the main limitations and offers recommendations for administering this drug in non-hospitalized COVID-19 patients at high risk for severe infection.

Plant-derived Ren's oligopeptide has antiviral effects on influenza virus and SARS-CoV-2

Influenza virus and SARS-CoV-2 virus are two important viruses that cause respiratory tract diseases. The high-frequency mutation of the two types of viruses leads to failure of the durable immune protection of vaccines, meanwhile it also poses continuous challenges to the development of antiviral drugs. Traditional Chinese medicine contains large number of biologically active compounds, and some of them contain broad-spectrum antiviral ingredients. In this study, we extracted antiviral active ingredients from medicinal and edible plants by biotransformation and enzymatic hydrolysis as a drug, and we named this drug Ren's oligopeptide. Further, we analyzed the antiviral activity of this drug and found that Ren's oligopeptide could inhibit the replication of influenza virus and SARS-CoV-2 virus with high anti-virus activities. In vitro experiments showed that the antiviral activity of the Ren's oligopeptide mainly targets the replication process after virus enters the cell. Therefore, Ren's oligopeptide is a promising drug against influenza and COVID-19.

A Clinical Insight on New Discovered Molecules and Repurposed Drugs for the Treatment of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began churning out incredulous terror in December 2019. Within several months from its first detection in Wuhan, SARS-CoV-2 spread to the rest of the world through droplet infection, making it a pandemic situation and a healthcare emergency across the globe. The available treatment of COVID-19 was only symptomatic as the disease was new and no approved drug or vaccine was available. Another challenge with COVID-19 was the continuous mutation of the SARS-CoV-2 virus. Some repurposed drugs, such as hydroxychloroquine, chloroquine, and remdesivir, received emergency use authorization in various countries, but their clinical use is compromised with either severe and fatal adverse effects or nonavailability of sufficient clinical data. Molnupiravir was the first molecule approved for the treatment of COVID-19, followed by Paxlovid™, monoclonal antibodies (MAbs), and others. New molecules have variable therapeutic efficacy against different variants or strains of SARS-CoV-2, which require further investigations. The aim of this review is to provide in-depth information on new molecules and repurposed drugs with emphasis on their general description, mechanism of action (MOA), correlates of protection, dose and dosage form, route of administration, clinical trials, regulatory approval, and marketing authorizations.

The Benefits of Molnupiravir Treatment in Healthcare Facilities Patients with COVID-19

Background

Molnupiravir (MOL) is an oral antiviral medication that has recently been treated for COVID-19.

Objectively

We perform a prospective and observational study to elucidate the efficacy and safety of MOL in healthcare patients with COVID-19.

Materials and Methods

A observational, non-randomized study of patients diagnosed with COVID-19 in 46 healthcare facilities and treated with MOL started within 5 days after the onset of signs or symptoms. We recorded data for all patients, including demographic data, clinical features, and symptoms. Treatment response was classified into cure, stable, hospitalization and death. Multivariate analysis was performed with stepwise logistic regression for hospitalization and death risk factors.

Results

In total, 856 patients were diagnosed as having COVID-19 and treated with MOL during the study period. Of those, 496 patients (57.9%) were cured, 256 patients (29.9%) in stable condition, 104 patients (12.2%) hospitalized, and 22 patients (2.6%) died, respectively. There was significant effectiveness (87.8%) in COVID-19 patients using MOL. Multivariate analysis was performed to confirm the risk factors for hospitalization and death and included elder age (>80 years old) (odds ratio (OR) 2.2, 95% confidence interval (CI): 1.1-6.9), old cerebrovascular accident (CVA) (OR=4.1, 95% CI: 1.3-9.9), the presence of diabetes mellitus (DM) (OR=2.6, 95% CI: 1.2-9.1) and chronic respiratory diseases (OR=2.4, 95% (CI): 1.3-8.1).

Limitations

This is an observational study, neither randomized study nor control group study.

Conclusion

Initial treatment with MOL has the treatment benefits and is well tolerated for patients with COVID-19 in healthcare facilities. Older age, old CVA, DM, and chronic respiratory diseases were independent risk factors for hospitalization and mortality. The results demonstrate there are important clinical benefits of MOL beyond the reduction in hospitalization or death for these patients with more comorbidities in Taiwan.

A Clinical Update on SARS-CoV-2: Pathology and Development of Potential Inhibitors

SARS-CoV-2 (severe acute respiratory syndrome) is highly infectious and causes severe acute respiratory distress syndrome (SARD), immune suppression, and multi-organ failure. For SARS-CoV-2, only supportive treatment options are available, such as oxygen supportive therapy, ventilator support, antibiotics for secondary infections, mineral and fluid treatment, and a significant subset of repurposed effective drugs. Viral targeted inhibitors are the most suitable molecules, such as ACE2 (angiotensin-converting enzyme-2) and RBD (receptor-binding domain) protein-based inhibitors, inhibitors of host proteases, inhibitors of viral proteases 3CLpro (3C-like proteinase) and PLpro (papain-like protease), inhibitors of replicative enzymes, inhibitors of viral attachment of SARS-CoV-2 to the ACE2 receptor and TMPRSS2 (transmembrane serine proteinase 2), inhibitors of HR1 (Heptad Repeat 1)-HR2 (Heptad Repeat 2) interaction at the S2 protein of the coronavirus, etc. Targeting the cathepsin L proteinase, peptide analogues, monoclonal antibodies, and protein chimaeras as RBD inhibitors interferes with the spike protein's ability to fuse to the membrane. Targeting the cathepsin L proteinase, peptide analogues, monoclonal antibodies, and protein chimaeras as RBD inhibitors interferes with the spike protein's ability to fuse to the membrane. Even with the tremendous progress made, creating effective drugs remains difficult. To develop COVID-19 treatment alternatives, clinical studies are examining a variety of therapy categories, including antibodies, antivirals, cell-based therapy, repurposed diagnostic medicines, and more. In this article, we discuss recent clinical updates on SARS-CoV-2 infection, clinical characteristics, diagnosis, immunopathology, the new emergence of variant, SARS-CoV-2, various approaches to drug development and treatment options. The development of therapies has been complicated by the global occurrence of many SARS-CoV-2 mutations. Discussion of this manuscript will provide new insight into drug pathophysiology and drug development.

Evaluation of molnupiravir (EIDD-2801) efficacy against SARS-CoV-2 in the rhesus macaque model

Molnupiravir (EIDD-2801) is a prodrug of a ribonucleoside analogue that is currently being used under a US FDA emergency use authorization for the treatment of mild to moderate COVID-19. We evaluated molnupiravir for efficacy as an oral treatment in the rhesus macaque model of SARS-CoV-2 infection. Twenty non-human primates (NHPs) were challenged with SARS-CoV-2 and treated with 75 mg/kg (n = 8) or 250 mg/kg (n = 8) of molnupiravir twice daily by oral gavage for 7 days. The NHPs were observed for 14 days post-challenge and monitored for clinical signs of disease. After challenge, all groups showed a trend toward increased respiration rates. Treatment with molnupiravir significantly reduced viral RNA levels in bronchoalveolar lavage (BAL) samples at Days 7 and 10. Considering the mild to moderate nature of SARS-CoV-2 infection in the rhesus macaque model, this study highlights the importance of monitoring the viral load in the lung as an indicator of pharmaceutical efficacy for COVID-19 treatments. Additionally, this study provides evidence of the efficacy of molnupiravir which supplements the current ongoing clinical trials of this drug.

Small molecules in the treatment of COVID-19

The outbreak of COVID-19 has become a global crisis, and brought severe disruptions to societies and economies. Until now, effective therapeutics against COVID-19 are in high demand. Along with our improved understanding of the structure, function, and pathogenic process of SARS-CoV-2, many small molecules with potential anti-COVID-19 effects have been developed. So far, several antiviral strategies were explored. Besides directly inhibition of viral proteins such as RdRp and M^pro, interference of host enzymes including ACE2 and proteases, and blocking relevant immunoregulatory pathways represented by JAK/STAT, BTK, NF-κB, and NLRP3 pathways, are regarded feasible in drug development. The development of small molecules to treat COVID-19 has been achieved by several strategies, including computer-aided lead compound design and screening, natural product discovery, drug repurposing, and combination therapy. Several small molecules representative by remdesivir and paxlovid have been proved or authorized emergency use in many countries. And many candidates have entered clinical-trial stage. Nevertheless, due to the epidemiological features and variability issues of SARS-CoV-2, it is necessary to continue exploring novel strategies against COVID-19. This review discusses the current findings in the development of small molecules for COVID-19 treatment. Moreover, their detailed mechanism of action, chemical structures, and preclinical and clinical efficacies are discussed.

Efficacy of favipiravir and molnupiravir against novel SARS-CoV-2 variants in vitro and in vivo

The COVID-19 disease pandemic remains a significant global problem, resulting in hundreds of millions of cases and millions of deaths. The search for specific inhibitors of SARS-CoV-2 for the treatment of this infection remains relevant. Drugs such as Favipiravir and Molnupiravir, which exhibit specific antiviral activity against SARS-CoV-2, are already being used to treat patients. However, there is limited evidence of their effectiveness, especially against novel genetic variants of the COVID-19 pathogen. The aim of this study was to investigate the antiviral effect of these drugs using an in vitro experimental model of SARS-CoV-2 infection in Vero E6 cell culture and an animal model of infection using Syrian hamsters. It has been established that Molnupiravir has an inhibitory effect against variants of the SARS-CoV-2 with IC50 values from 16.51 to 7.88 μM in vitro, and reduces the infectious titer of the virus in the lungs of animals by ~1.5 Log10 in vivo, in while Favipiravir shows lower activity and severe toxicity. Dose selection and frequency of use remain unexplored.

The preclinical discovery and development of molnupiravir for the treatment of SARS-CoV-2 (COVID-19)

INTRODUCTION

Molnupiravir (MOV) is a broad-spectrum oral antiviral agent approved for the treatment of COVID-19. The results from in vitro and in vivo studies suggested MOV activity against many RNA viruses such as influenza virus and some alphaviruses agents of epidemic encephalitis. MOV is a prodrug metabolized into the ribonucleoside analog β-D-N⁴-hydroxycytidine. It is incorporated into the viral RNA chain causing mutations impairing coding activity of the virus, thereby inhibiting viral replication.

AREAS COVERED

This review analyzes the in vitro and in vivo studies that have highlighted the efficacy of MOV and the main pre-authorization randomized controlled trials evaluating its safety, tolerability, and pharmacokinetics, as well as its antiviral efficacy against SARS-COV-2 infection.

EXPERT OPINION

MOV is an antiviral agent with an excellent tolerability profile with few drug-drug interactions. Treatment of mild-to-moderate COVID-19 can benefit from MOV administration in the precocious phases of the disease, prior to the trigger of an aberrant immune response responsible for the parenchymal damage to pulmonary and extrapulmonary tissues. However, its suspected mutagenic effect can be a factor limiting its use at least in selected populations and studies on its teratogen effects should be planned before it is authorized for use in the pediatric population or in pregnant women.

Repurposing Molnupiravir as a new opportunity to treat COVID-19

With the emergence of new and re-emerging viral diseases, scientists have been working to produce new medications with novel targets and pathways. The discovery of safe and efficacious antiviral medicines is critical due to the constant introduction of new virus types and short lifetime of protection. Since the outbreak, there have been significant efforts to repurpose existing and licensed medications for rapid human testing and possible emergency use authorizations. The exploration of surviving medications for new restorative motives is known as drug repurposing. It is a successful, rapid, and highly reliable alternative to traditional drug methods. COVID-19 is being treated using a number of repurposed and new medicines. Molnupiravir is a repurposed Covid-19 medicine that was specifically developed to cure influenza and is used to treat mild to moderately ill Covid-19 patients with high risk of becoming seriously ill. The importance of medication repurposing, as well as the regulatory procedure for repurposed pharmaceuticals and Emergency Use Authorization in the United States, are summarized in this article.

An Overview of Repurposed Drugs for Potential COVID-19 Treatment

The COVID-19 pandemic caused by SARS-CoV-2 has placed severe constraints on healthcare systems around the globe. The SARS-CoV-2 virus has caused upheaval in the healthcare and economic sectors worldwide. On the 20th of May 2020, the World Health Organisation declared COVID-19 a global pandemic due to the unprecedented number of cases reported around the globe. As of the 4th of November 2022, there were 637,117,429 coronavirus cases reported globally by Worldometer stats, with 6,602,572 related deaths. In South Africa, there were approximately 4,029,496 coronavirus cases and 102,311 associated deaths. As such, there is a need for efficacious therapeutic regimes. There has been a paucity of knowledge encompassing the use of effective and specific antiviral drug therapies for treating COVID-19 since the outbreak. In this review, we provide valuable insights into the repurposing of current drugs for COVID-19. Drug repurposing provides a suitable option for the discovery of efficacious drugs for COVID-19, thereby decreasing the costs and turnaround times of drug development strategies. This review provides an overview of ten drugs, including antimalarial, antiparasitic, anti-inflammatory, nucleoside analogue, monoclonal-antibody drugs, that were repurposed for the potential treatment of COVID-19.

Protein Kinase C Inhibitors Reduce SARS-CoV-2 Replication in Cultured Cells

Infection by severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has posed a severe threat to global public health. The current study revealed that several inhibitors of protein kinases C (PKCs) possess protective activity against SARS-CoV-2 infection. Four pan-PKC inhibitors, Go 6983, bisindolylmaleimide I, enzastaurin, and sotrastaurin, reduced the replication of a SARS-CoV-2 replicon in both BHK-21 and Huh7 cells. A PKCδ-specific inhibitor, rottlerin, was also effective in reducing viral infection. The PKC inhibitors acted at an early step of SARS-CoV-2 infection. Finally, PKC inhibitors blocked the replication of wild-type SARS-CoV-2 in ACE2-expressing A549 cells. Our work highlights the importance of the PKC signaling pathway in infection by SARS-CoV-2 and provides evidence that PKC-specific inhibitors are potential therapeutic agents against SARS-CoV-2. IMPORTANCE There is an urgent need for effective therapeutic drugs to control the pandemic caused by severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). We found that several inhibitors of protein kinases C (PKCs) dramatically decrease the replication of SARS-CoV-2 in cultured cells. These PKC inhibitors interfere with an early step of viral infection. Therefore, the rapid and prominent antiviral effect of PKC inhibitors underscores that they are promising antiviral agents and suggests that PKCs are important host factors involved in infection by SARS-CoV-2.

Progress, pitfalls, and path forward of drug repurposing for COVID-19 treatment

On 30 January 2020, the World Health Organization (WHO) declared the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic a public health emergency of international concern. The viral outbreak led in turn to an exponential growth of coronavirus disease 2019 (COVID-19) cases, that is, a multiorgan disease that has led to more than 6.3 million deaths worldwide, as of June 2022. There are currently few effective drugs approved for treatment of SARS-CoV-2/COVID-19 patients. Many of the compounds tested so far have been selected through a drug repurposing approach, that is, by identifying novel indications for drugs already approved for other conditions. We here present an up-to-date review of the main Food and Drug Administration (FDA)-approved drugs repurposed against SARS-CoV-2 infection, discussing their mechanism of action and their most important preclinical and clinical results. Reviewed compounds were chosen to privilege those that have been approved for use in SARS-CoV-2 patients or that have completed phase III clinical trials. Moreover, we also summarize the evidence on some novel and promising repurposed drugs in the pipeline. Finally, we discuss the current stage and possible steps toward the development of broadly effective drug combinations to suppress the onset or progression of COVID-19.

Efficacy of Lactococcus lactis strain plasma (LC-Plasma) in easing symptoms in patients with mild COVID-19: protocol for an exploratory, multicentre, double-blinded, randomised controlled trial (PLATEAU study)

INTRODUCTION

The COVID-19 pandemic has been a major concern worldwide; however, easily accessible treatment options for patients with mild COVID-19 remain limited. Since the oral intake of Lactococcus lactis strain plasma (LC-Plasma) enhances both the innate and acquired immune systems through the activation of plasmacytoid dendritic cells (pDCs), we hypothesised that the oral intake of LC-Plasma could aid the relief or prevention of symptoms in patients with asymptomatic or mild COVID-19.

METHODS AND ANALYSIS

This is an exploratory, multicentre, double-blinded, randomised, placebo-controlled trial. This study was initiated in December 2021 and concludes in April 2023. The planned number of enrolled subjects is 100 (50 subjects×2 groups); subject enrolment will be conducted until October 2022. Patients with asymptomatic or mild COVID-19 will be enrolled and randomly assigned in a 1:1 ratio to group A (oral intake of LC-Plasma-containing capsule, 200 mg/day, for 14 days) or group B (oral intake of placebo capsule, for 14 days). The primary endpoint is the change in subjective symptoms measured by the severity score. Secondary endpoints include SARS-CoV-2 viral loads, biomarkers for pDC activation, serum SARS-CoV-2-specific antibodies, serum cytokines, interferon and interferon-inducible antiviral effectors and the proportion of subjects with emergency room visits to medical institutions or who are hospitalised.

ETHICS AND DISSEMINATION

The study protocol was approved by the Clinical Research Review Board of Nagasaki University, in accordance with the Clinical Trials Act of Japan. The study will be conducted in accordance with the Declaration of Helsinki, the Clinical Trials Act, and other current legal regulations in Japan. Written informed consent will be obtained from all the participants. The results of this study will be reported in journal publications.

TRIAL REGISTRATION NUMBER

Japan Registry of Clinical Trials (registration number: jRCTs071210097).

The MEK1/2 Inhibitor ATR-002 (Zapnometinib) Synergistically Potentiates the Antiviral Effect of Direct-Acting Anti-SARS-CoV-2 Drugs

The coronavirus disease 2019 (COVID-19) represents a global public health burden. In addition to vaccination, safe and efficient antiviral treatment strategies to restrict the viral spread within the patient are urgently needed. An alternative approach to a single-drug therapy is the combinatory use of virus- and host-targeted antivirals, leading to a synergistic boost of the drugs’ impact. In this study, we investigated the property of the MEK1/2 inhibitor ATR-002’s (zapnometinib) ability to potentiate the effect of direct-acting antivirals (DAA) against SARS-CoV-2 on viral replication. Treatment combinations of ATR-002 with nucleoside inhibitors Molnupiravir and Remdesivir or 3C-like protease inhibitors Nirmatrelvir and Ritonavir, the ingredients of the drug Paxlovid, were examined in Calu-3 cells to evaluate the advantage of their combinatory use against a SARS-CoV-2 infection. Synergistic effects could be observed for all tested combinations of ATR-002 with DAAs, as calculated by four different reference models in a concentration range that was very well-tolerated by the cells. Our results show that ATR-002 has the potential to act synergistically in combination with direct-acting antivirals, allowing for a reduction in the effective concentrations of the individual drugs and reducing side effects.

Advances and applications of monoolein as a novel nanomaterial in mitigating chronic lung diseases

Chronic lung diseases such as asthma, chronic obstructive pulmonary disease, lung cancer, and the recently emerged COVID-19, are a huge threat to human health, and among the leading causes of global morbidity and mortality every year. Despite availability of various conventional therapeutics, many patients remain poorly controlled and have a poor quality of life. Furthermore, the treatment and diagnosis of these diseases are becoming increasingly challenging. In the recent years, the application of nanomedicine has become increasingly popular as a novel strategy for diagnosis, treatment, prevention, as well as follow-up of chronic lung diseases. This is attributed to the ability of nanoscale drug carriers to achieve targeted delivery of therapeutic moieties with specificity to diseased site within the lung, thereby enhancing therapeutic outcomes of conventional therapies whilst minimizing the risks of adverse reactions. For this instance, monoolein is a polar lipid nanomaterial best known for its versatility, thermodynamic stability, biocompatibility, and biodegradability. As such, it is commonly employed in liquid crystalline systems for various drug delivery applications. In this review, we present the applications of monoolein as a novel nanomaterial-based strategy for targeted drug delivery with the potential to revolutionize therapeutic approaches in chronic lung diseases.

An Efficient Modern Strategy to Screen Drug Candidates Targeting RdRp of SARS-CoV-2 With Potentially High Selectivity and Specificity

Desired drug candidates should have both a high potential binding chance and high specificity. Recently, many drug screening strategies have been developed to screen compounds with high possible binding chances or high binding affinity. However, there is still no good solution to detect whether those selected compounds possess high specificity. Here, we developed a reverse DFCNN (Dense Fully Connected Neural Network) and a reverse docking protocol to check a given compound’s ability to bind diversified targets and estimate its specificity with homemade formulas. We used the RNA-dependent RNA polymerase (RdRp) target as a proof-of-concept example to identify drug candidates with high selectivity and high specificity. We first used a previously developed hybrid screening method to find drug candidates from an 8888-size compound database. The hybrid screening method takes advantage of the deep learning-based method, traditional molecular docking, molecular dynamics simulation, and binding free energy calculated by metadynamics, which should be powerful in selecting high binding affinity candidates. Also, we integrated the reverse DFCNN and reversed docking against a diversified 102 proteins to the pipeline for assessing the specificity of those selected candidates, and finally got compounds that have both predicted selectivity and specificity. Among the eight selected candidates, Platycodin D and Tubeimoside III were confirmed to effectively inhibit SARS-CoV-2 replication in vitro with EC₅₀ values of 619.5 and 265.5 nM, respectively. Our study discovered that Tubeimoside III could inhibit SARS-CoV-2 replication potently for the first time. Furthermore, the underlying mechanisms of Platycodin D and Tubeimoside III inhibiting SARS-CoV-2 are highly possible by blocking the RdRp cavity according to our screening procedure. In addition, the careful analysis predicted common critical residues involved in the binding with active inhibitors Platycodin D and Tubeimoside III, Azithromycin, and Pralatrexate, which hopefully promote the development of non-covalent binding inhibitors against RdRp.

Rapid Review and Meta‐Analysis of Adverse Events Associated with Molnupiravir in Patients with COVID‐19

Aims

The aim of this study was to evaluate the safety profile of molnupiravir in COVID‐19 patients.

Methods

PubMed, Cochrane Library, medRxive and Google Scholar were searched for articles published up to April 25, 2022. Meta‐analysis was performed using Comprehensive Meta‐Analysis software.

Results

Four trials involving 2241 patients met the inclusion criteria. No significant difference was observed between molnupiravir at 200, 400 and 800 mg compared with placebo (200 mg: risk ratio [RR] = 0.97; 95% confidence interval [CI]: 0.78–1.20; P = .80; 400 mg: RR = 0.81; 95% CI: 0.64–1.02; P = .07; 800 mg: RR = 0.94; 95% CI: 0.83–1.06; P = .36) for any adverse events (AEs); at 200, 400 and 800 mg compared with placebo (200 mg: RR = 0.81; 95% CI: 0.41–1.63; P = .57; 400 mg: RR = 0.82; 95% CI: 0.41–1.61; P = .56; 800 mg: RR = 0.80; 95% CI: 0.59–1.08; P = .15) for serious adverse events; at 200, 400 and 800 mg compared with placebo (200 mg: RR = 1.74; 95% CI: 0.48–6.30; P = .39; 400 mg: RR = 1.07; 95% CI: 0.28–4.09; P = .91; 800 mg: RR = 0.47; 95% CI: 0.17–1.28; P = .14) for AEs leading to death; and at 200, 400 and 800 mg compared with placebo (200 mg: RR = 1.50; 95% CI: 0.26–8.55; P = .64; 400 mg: RR = 0.99; 95% CI: 0.17–5.68; P = .99; 800 mg: RR = 0.61; 95% CI: 0.31–1.23; P = .17) for treatment discontinuation due to AEs.

Conclusion

This meta‐analysis showed that the use of three doses of molnupiravir (200, 400 and 800 mg) is safe for COVID‐19 patients. Further research is needed to confirm the present findings.

Repurposing Molnupiravir for COVID-19: The Mechanisms of Antiviral Activity

Molnupiravir is a β-d-N4-hydroxycytidine-5'-isopropyl ester (NHC) compound that exerts antiviral activity against various RNA viruses such as influenza, SARS, and Ebola viruses. Thus, the repurposing of Molnupiravir has gained significant attention for combatting infection with SARS-CoV-2, the etiological agent of COVID-19. Recently, Molnupiravir was granted authorization for the treatment of mild-to-moderate COVID-19 in adults. Findings from in vitro experiments, in vivo studies and clinical trials reveal that Molnupiravir is effective against SARS-CoV-2 by inducing viral RNA mutagenesis, thereby giving rise to mutated complementary RNA strands that generate non-functional viruses. To date, the data collectively suggest that Molnupiravir possesses promising antiviral activity as well as favorable prophylactic efficacy, attributed to its effective mutagenic property of disrupting viral replication. This review discusses the mechanisms of action of Molnupiravir and highlights its clinical utility by disabling SARS-CoV-2 replication, thereby ameliorating COVID-19 severity. Despite relatively few short-term adverse effects thus far, further detailed clinical studies and long-term pharmacovigilance are needed in view of its mutagenic effects.

Emergence of SARS-CoV-2 Omicron (B.1.1.529) variant, salient features, high global health concerns and strategies to counter it amid ongoing COVID-19 pandemic

Since the appearance in the late of December 2019, SARS-CoV-2 is rapidly evolving and mutating continuously, giving rise to various variants with variable degrees of infectivity and lethality. The virus that initially appeared in China later mutated several times, wreaking havoc and claiming many lives worldwide amid the ongoing COVID-19 pandemic. After Alpha, Beta, Gamma, and Delta variants, the most recently emerged variant of concern (VOC) is the Omicron (B.1.1.529) that has evolved due to the accumulation of high numbers of mutations especially in the spike protein, raising concerns for its ability to evade from pre-existing immunity acquired through vaccination or natural infection as well as overpowering antibodies-based therapies. Several theories are on the surface to explain how the Omicron has gathered such a high number of mutations within less time. Few of them are higher mutation rates within a subgroup of population and then its introduction to a larger population, long term persistence and evolution of the virus in immune-compromised patients, and epizootic infection in animals from humans, where under different immune pressures the virus mutated and then got reintroduced to humans. Multifaceted approach including rapid diagnosis, genome analysis of emerging variants, ramping up of vaccination drives and receiving booster doses, efficacy testing of vaccines and immunotherapies against newly emerged variants, updating the available vaccines, designing of multivalent vaccines able to generate hybrid immunity, up-gradation of medical facilities and strict implementation of adequate prevention and control measures need to be given high priority to handle the on-going SARS-CoV-2 pandemic successfully.

Molnupiravir and Its Active Form, EIDD-1931, Show Potent Antiviral Activity against Enterovirus Infections In Vitro and In Vivo

Enterovirus infections can cause hand, foot, and mouth disease (HFDM), aseptic meningitis, encephalitis, myocarditis, and acute flaccid myelitis, leading to death of infants and young children. However, no specific antiviral drug is currently available for the treatment of this type of infection. The Unites States and United Kingdom health authorities recently approved a new antiviral drug, molnupiravir, for the treatment of COVID-19. In this study, we reported that molnupiravir (EIDD-2801) and its active form, EIDD-1931, have broad-spectrum anti-enterovirus potential. Our data showed that EIDD-1931 could significantly reduce the production of EV-A71 progeny virus and the expression of EV-A71 viral protein at non-cytotoxic concentrations. The results of the time-of-addition assay suggest that EIDD-1931 acts at the post-entry step, which is in accordance with its antiviral mechanism. The intraperitoneal administration of EIDD-1931 and EIDD-2801 protected 1-day-old ICR suckling mice from lethal EV-A71 challenge by reducing the viral load in various tissues of the infected mice. The pharmacokinetics analysis indicated that the plasma drug concentration overwhelmed the EC₅₀ for enteroviruses, suggesting the clinical potential of molnupiravir against enteroviruses. Thus, molnupiravir along with its active form, EIDD-1931, may be a promising drug candidate against enterovirus infections.

Human Identical Sequences, hyaluronan, and hymecromone ─ the new mechanism and management of COVID-19

COVID-19 caused by SARS-CoV-2 has created formidable damage to public health and market economy. Currently, SARS-CoV-2 variants has exacerbated the transmission from person-to-person. Even after a great deal of investigation on COVID-19, SARS-CoV-2 is still rampaging globally, emphasizing the urgent need to reformulate effective prevention and treatment strategies. Here, we review the latest research progress of COVID-19 and provide distinct perspectives on the mechanism and management of COVID-19. Specially, we highlight the significance of Human Identical Sequences (HIS), hyaluronan, and hymecromone ("Three-H") for the understanding and intervention of COVID-19. Firstly, HIS activate inflammation-related genes to influence COVID-19 progress through NamiRNA-Enhancer network. Accumulation of hyaluronan induced by HIS-mediated HAS2 upregulation is a substantial basis for clinical manifestations of COVID-19, especially in lymphocytopenia and pulmonary ground-glass opacity. Secondly, detection of plasma hyaluronan can be effective for evaluating the progression and severity of COVID-19. Thirdly, spike glycoprotein of SARS-CoV-2 may bind to hyaluronan and further serve as an allergen to stimulate allergic reaction, causing sudden adverse effects after vaccination or the aggravation of COVID-19. Finally, antisense oligonucleotides of HIS or inhibitors of hyaluronan synthesis (hymecromone) or antiallergic agents could be promising therapeutic agents for COVID-19. Collectively, Three-H could hold the key to understand the pathogenic mechanism and create effective therapeutic strategies for COVID-19.

Antimicrobials in COVID-19: strategies for treating a COVID-19 pandemic

The COVID-19 pandemic continues to pose a serious global challenge, with the world engulfed in fighting second, third and fourth waves of the disease, which is reaching scary proportions in terms of cases and mortality in countries like India. Despite the urgent need of proven management protocols, there is still confusion about the best practices for treating COVID-19 with different pharmaceutical interventions. Antimicrobials are empirically used in COVID-19 patients. During the initial phase of this pandemic, hydroxychloroquine, ivermectin, azithromycin and doxycycline were widely suggested for possible prophylaxis or treatment for COVID-19 in outpatient as well as hospitalized settings. Various national and international guidelines recommended its use. However, cumulative evidence from subsequent clinical trials has revealed no significant clinical benefits in any setting, with the risk of adverse effects being high particularly in combination with azithromycin. Yet, there is continued use of antimicrobials particularly in outpatient settings which should be avoided because there is no justifiable rationale for doing so. Antimicrobial resistance (AMR) was one of the top problems for global public health before the coronavirus 2019 (COVID-19) pandemic began. AMR, which is already a difficult problem, must now be handled in the context of a changing healthcare sector.

Molnupiravir and Its Antiviral Activity Against COVID-19

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) constitutes a major worldwide public health threat and economic burden. The pandemic is still ongoing and the SARS-CoV-2 variants are still emerging constantly, resulting in an urgent demand for new drugs to treat this disease. Molnupiravir, a biological prodrug of NHC (β-D-N(4)-hydroxycytidine), is a novel nucleoside analogue with a broad-spectrum antiviral activity against SARS-CoV, SARS-CoV-2, Middle East respiratory syndrome coronavirus (MERS-CoV), influenza virus, respiratory syncytial virus (RSV), bovine viral diarrhea virus (BVDV), hepatitis C virus (HCV) and Ebola virus (EBOV). Molnupiravir showed potent therapeutic and prophylactic activity against multiple coronaviruses including SARS-CoV-2, SARS-CoV, and MERS-CoV in animal models. In clinical trials, molnupiravir showed beneficial effects for mild to moderate COVID-19 patients with a favorable safety profile. The oral bioavailability and potent antiviral activity of molnupiravir highlight its potential utility as a therapeutic candidate against COVID-19. This review presents the research progress of molnupiravir starting with its discovery and synthesis, broad-spectrum antiviral effects, and antiviral mechanism. In addition, the preclinical studies, antiviral resistance, clinical trials, safety, and drug tolerability of molnupiravir are also summarized and discussed, aiming to expand our knowledge on molnupiravir and better deal with the COVID-19 epidemic.

Antibiotics and Therapeutic Agent Prescription in COVID-19 Management

During the coronavirus disease 2019 (COVID-19) pandemic, only few therapeutic options have been approved for the treatment of COVID-19 with substantial evidence [...]

Molnupiravir: First Approval

Molnupiravir (Lagevrio^®) is an orally-administered antiviral prodrug that inhibits replication of RNA viruses through viral error induction. It is being developed by Merck and Ridgeback Biotherapeutics for the prevention and treatment of Coronavirus disease 2019 (COVID-19). Molnupiravir received its first approval on 4 November 2021 in the UK for the treatment of mild to moderate COVID-19 in adults with a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostic test and who have at least one risk factor for developing severe illness. Molnupiravir is filed for approval and has emergency use authorization for the treatment of COVID-19 in several countries, including the USA, Japan and those in the EU. This article summarizes the milestones in the development of molnupiravir leading to this first approval for COVID-19.

Oral Nirmatrelvir/Ritonavir Therapy for COVID-19: The Dawn in the Dark?

Nirmatrelvir/ritonavir (Paxlovid™) is an effective and safe antiviral drug that inhibits the main protease (M^pro), 3CL protease, of SARS-CoV-2. A reduction in COVID-19-related hospitalization or death was observed in patients treated with nirmatrelvir/ritonavir within five days of symptom onset. Moreover, good oral availability enables the usage of nirmatrelvir/ritonavir, not only in hospitalized patients, but also among outpatients. Nirmatrelvir (PF-07321332) has been demonstrated to stop the spread of COVID-19 in animal models. Despite frequent mutations in the viral genomes of SARS-CoV-2, nirmatrelvir shows an effective antiviral effect against recent coronavirus mutants. Despite the promising antiviral effect of nirmatrelvir, there are several unresolved concerns. First, the final results of large-scale clinical trials for early therapy of mild cases of COVID-19 are not yet published. Second, the effectiveness of nirmatrelvir against upcoming variants in the coming years requires close monitoring. Considering the promising preliminary results of the EPIC-HR trial, nirmatrelvir/ritonavir in conjunction with vaccines and non-pharmacological interventions, may represent the dawn in the dark of the COVID-19 pandemic.

A computational comparative analysis of the binding mechanism of molnupiravir's active metabolite to RNA-dependent RNA polymerase of wild-type and Delta subvariant AY.4 of SARS-CoV-2

The antiviral drug molnupiravir targets the SARS-CoV-2 RNA-dependent RNA polymerase (RdRP) enzyme. Early treatment with molnupiravir reduced the risk of hospitalization or death in at-risk, unvaccinated adults with COVID-19, according to phase 3 clinical trials. Many mutations have occurred within this virus as a result of its widespread distribution. The current study sought to determine whether mutations in the RdRP of Delta subvariant AY.4 (D-AY.4 RdRP) influence the interaction of the enzyme with molnupiravir triphosphate (MTP), the active metabolite of molnupiravir. The interactions between the wild-type (WT) RdRP and D-AY.4 RdRP with MTP were evaluated based on molecular docking and dynamic simulation (MD) studies. The results show that the MTP interaction is stronger and more stable with D-AY.4 RdRP than with WT RdRP. This study provides insight into the potential significance of administering MTP to patients infected with D-AY.4 RdRP, which may have a more favorable chance of alleviating the illness. According to the findings of this study, MTP has a high likelihood of becoming widely used as an anti-SARS-CoV-2 agent. The fact that MTP is not only cytotoxic but also mutagenic to mammalian cells, as well as the possibility that it may cause DNA damage in the host, have all been raised as potential concerns.

Blocking viral infections by Lysine-based polymeric nanostructures. A critical review

The outbreak of the Covid-19 pandemic due to the SARS-CoV-2 coronavirus has accelerated the search for innovative antivirals with possibly broad-spectrum efficacy. One of the possible strategies is to inhibit...

CD19 B cell repopulation after ocrelizumab, alemtuzumab and cladribine: Implications for SARS-CoV-2 vaccinations in multiple sclerosis

BACKGROUND

Ocrelizumab maintains B-cell depletion via six-monthly dosing. Whilst this controls relapsing multiple sclerosis, it also inhibits seroconversion following SARS-CoV-2 vaccination unlike that seen following alemtuzumab and cladribine treatment. Emerging reports suggest that 1-3% B-cell repopulation facilitates seroconversion after CD20-depletion.

OBJECTIVE

To determine the frequency of B-cell repopulation levels during and after ocrelizumab treatment.

METHODS

Relapse data, lymphocyte and CD19 B-cell numbers were obtained following requests to clinical trial data-repositories. Information was extracted from the phase II ocrelizumab extension (NCT00676715) trial and the phase III cladribine tablet (NCT00213135) and alemtuzumab (NCT00530348/NCT00548405) trials obtained clinical trial data requests RESULTS: Only 3-5% of people with MS exhibit 1% B-cells at 6 months after the last infusion following 3-4 cycles of ocrelizumab, compared to 50-55% at 9 months, and 85-90% at 12 months. During this time relapses occurred at consistent disease-breakthrough rates compared to people during standard therapy. In contrast most people (90-100%) exhibited more than 1% B-cells during treatment with either cladribine or alemtuzumab.

CONCLUSIONS

Most people demonstrate B cell repletion within 3 months of the last treatment of alemtuzumab and cladribine. However, few people repopulate peripheral B-cells with standard ocrelizumab dosing. Controlled studies are warranted to examine a view that delaying the dosing interval by 3-6 months may allow more people to potentially seroconvert after vaccination.

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.

Coronavirus Disease (COVID-19) Control between Drug Repurposing and Vaccination: A Comprehensive Overview

Respiratory viruses represent a major public health concern, as they are highly mutated, resulting in new strains emerging with high pathogenicity. Currently, the world is suffering from the newly evolving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This virus is the cause of coronavirus disease 2019 (COVID-19), a mild-to-severe respiratory tract infection with frequent ability to give rise to fatal pneumonia in humans. The overwhelming outbreak of SARS-CoV-2 continues to unfold all over the world, urging scientists to put an end to this global pandemic through biological and pharmaceutical interventions. Currently, there is no specific treatment option that is capable of COVID-19 pandemic eradication, so several repurposed drugs and newly conditionally approved vaccines are in use and heavily applied to control the COVID-19 pandemic. The emergence of new variants of the virus that partially or totally escape from the immune response elicited by the approved vaccines requires continuous monitoring of the emerging variants to update the content of the developed vaccines or modify them totally to match the new variants. Herein, we discuss the potential therapeutic and prophylactic interventions including repurposed drugs and the newly developed/approved vaccines, highlighting the impact of virus evolution on the immune evasion of the virus from currently licensed vaccines for COVID-19.