Antiparasitic Drug Ivermectin Research Articles

Dengue virus NS1 secretion is regulated via importin-subunit β1 controlling expression of the chaperone GRp78 and targeted by the clinical drug ivermectin.

Dengue virus (DENV) is a major human pathogen that can cause hemorrhagic fever and shock syndrome. One important factor of DENV pathogenicity is non-structural protein 1 (NS1), a glycoprotein that is secreted from infected cells. Here we study the mode of action of the widely used drug ivermectin, used to treat parasitic infections and recently shown to lower NS1 blood levels in DENV-infected patients. We found that ivermectin blocks the nuclear transport of transcription factors required for the expression of chaperones that support the folding and secretion of glycoproteins, including NS1. Impairing nuclear transport of these transcription factors by ivermectin or depleting them from infected cells dampens NS1 folding and thus its secretion. These results reveal a novel mode of action of ivermectin that might apply to other flaviviruses as well.

Computational Prediction of the Interaction of Ivermectin with Fibrinogen.

Hypercoagulability and formation of extensive and difficult-to-lyse microclots are a hallmark of both acute COVID-19 and long COVID. Fibrinogen, when converted to fibrin, is responsible for clot formation, but abnormal structural and mechanical clot properties can lead to pathologic thrombosis. Recent experimental evidence suggests that the spike protein (SP) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may directly bind to the blood coagulation factor fibrinogen and induce structurally abnormal blood clots with heightened proinflammatory activity. Accordingly, in this study, we used molecular docking and molecular dynamics simulations to explore the potential activity of the antiparasitic drug ivermectin (IVM) to prevent the binding of the SARS-CoV-2 SP to fibrinogen and reduce the occurrence of microclots. Our computational results indicate that IVM may bind with high affinity to multiple sites on the fibrinogen peptide, with binding more likely in the central, E region, and in the coiled-coil region, as opposed to the globular D region. Taken together, our in silico results suggest that IVM may interfere with SP-fibrinogen binding and, potentially, decrease the formation of fibrin clots resistant to degradation. Additional in vitro studies are warranted to validate whether IVM binding to fibrinogen is sufficiently stable to prevent interaction with the SP, and potentially reduce its thrombo-inflammatory effect in vivo.

Drug repurposing for COVID-19: current evidence from randomized controlled adaptive platform trials and living systematic reviews.

The coronavirus disease 2019 (COVID-19) pandemic resulted in a race to develop effective treatments largely through drug repurposing via adaptive platform trials on a global scale. Drug repurposing trials have focused on potential antiviral therapies aimed at preventing viral replication, anti-inflammatory agents, antithrombotic agents and immune modulators through a number of adaptive platform trials. Living systematic reviews have also enabled evidence synthesis and network meta-analysis as clinical trial data emerge globally. Recent published literature. Corticosteroids and immunomodulators that antagonize the interleukin-6 (IL-6) receptor have been shown to play a critical role in modulating inflammation and improving clinical outcomes in hospitalized patients. Inhaled budesonide reduces the time to recovery in older patients with mild-to-moderate COVID-19 managed in the community. The clinical benefit of remdesivir remains controversial with conflicting evidence from different trials. Remdesivir led to a reduction in time to clinical recovery in the ACTT-1 trial. However, the World Health Organization SOLIDARITY and DISCOVERY trial did not find a significant benefit on 28-day mortality and clinical recovery. Other treatments currently being investigated include antidiabetic drug empagliflozin, antimalarial drug artesunate, tyrosine kinase inhibitor imatinib, immunomodulatory drug infliximab, antiviral drug favipiravir, antiparasitic drug ivermectin and antidepressant drug fluvoxamine. The timing of therapeutic interventions based on postulated mechanisms of action and the selection of clinically meaningful primary end points remain important considerations in the design and implementation of COVID-19 therapeutic trials.

Ivermectin Augments the Anti-Cancer Activity of Pitavastatin in Ovarian Cancer Cells.

We have previously shown that pitavastatin has the potential to be used to treat ovarian cancer, although relatively high doses are likely to be necessary. One solution to this problem is to identify drugs that are synergistic with pitavastatin, thereby reducing the dose that is necessary to have a therapeutic effect. Here, we tested combinations of pitavastatin with the anti-parasitic drug ivermectin in six ovarian cancer cell lines. When tested on its own, ivermectin inhibited the growth of the cells but only with modest potency (IC50 = 10-20 µM). When the drugs were combined and assessed in cell growth assays, ivermectin showed synergy with pitavastatin in 3 cell lines and this was most evident in COV-318 cells (combination index ~ 0.6). Ivermectin potentiated the reduction in COV-318 cell viability caused by pitavastatin by 20-25% as well as potentiating apoptosis induced by pitavastatin, assessed by activation of caspase-3/7 (2-4 fold) and annexin-labelling (3-5 fold). These data suggest that ivermectin may be useful in the treatment of ovarian cancer when combined with pitavastatin, but methods to achieve an adequate ivermectin concentration in tumour tissue will be necessary.

Is the antiparasitic drug ivermectin a suitable candidate for the treatment of epilepsy?

There are only a few drugs that can seriously lay claim to the title of "wonder drug," and ivermectin, the world's first endectocide and forerunner of a completely new class of antiparasitic agents, is among them. Ivermectin, a mixture of two macrolytic lactone derivatives (avermectin B1a and B1b in a ratio of 80:20), exerts its highly potent antiparasitic effect by activating the glutamate-gated chloride channel, which is absent in vertebrate species. However, in mammals, ivermectin activates several other Cys-loop receptors, including the inhibitory γ-aminobutyric acid type A and glycine receptors and the excitatory nicotinic acetylcholine receptor of brain neurons. Based on these effects on vertebrate receptors, ivermectin has recently been proposed to constitute a multifaceted wonder drug for various novel neurological indications, including alcohol use disorders, motor neuron diseases, and epilepsy. This review critically discusses the preclinical and clinical evidence of antiseizure effects of ivermectin and provides several arguments supporting that ivermectin is not a suitable candidate drug for the treatment of epilepsy. First, ivermectin penetrates the mammalian brain poorly, so it does not exert any pharmacological effects via mammalian ligand-gated ion channels in the brain unless it is used at high, potentially toxic doses or the blood-brain barrier is functionally impaired. Second, ivermectin is not selective but activates numerous inhibitory and excitatory receptors. Third, the preclinical evidence for antiseizure effects of ivermectin is equivocal, and at least in part, median effective doses in seizure models are in the range of the median lethal dose. Fourth, the only robust clinical evidence of antiseizure effects stems from the treatment of patients with onchocerciasis, in which the reduction of seizures is due to a reduction in microfilaria densities but not a direct antiseizure effect of ivermectin. We hope that this critical analysis of available data will avert the unjustified hype associated with the recent use of ivermectin to control COVID-19 from recurring in neurological diseases such as epilepsy.

Ivermectin-induced bacterial gut dysbiosis does not increase susceptibility to Pseudomonas aeruginosa lung infection but exacerbates liver damage

Excessive use of medications, including the antiparasitic drug ivermectin, can lead to bacterial gut dysbiosis, an imbalance in the intestinal microbiome, which in turn may increase or decrease susceptibility to infectious processes. To better understand the effects of continuous ivermectin usage on the gut bacterial community, C57BL/6 isogenic mice were treated by gavage with ivermectin or saline. Ivermectin-induced bacterial gut dysbiosis is characterized by a decrease in Bacteroidetes, Firmicutes, Proteobacteria and Tenericutes and an increase in species of the phylum Verrucomicrobia. A pro-inflammatory immunostimulatory caecal content, as well as disruption of caecal tissue organization and liver tissue damage, was observed in mice with gut dysbiosis. However, ivermectin-induced gut dysbiosis did not lead to acute susceptibility to Pseudomonas aeruginosa lung infection: infected mice with and without gut dysbiosis showed similar rates of recovery of viable bacteria in organs, histopathology and differential cytokine expression in the lung. Therefore, an extension of liver damage was observed in ivermectin-treated and P. aeruginosa-infected mice, which was exacerbated by infection.

Transcriptomic analyses implicate neuronal plasticity and chloride homeostasis in ivermectin resistance and response to treatment in a parasitic nematode.

The antiparasitic drug ivermectin plays an essential role in human and animal health globally. However, ivermectin resistance is widespread in veterinary helminths and there are growing concerns of sub-optimal responses to treatment in related helminths of humans. Despite decades of research, the genetic mechanisms underlying ivermectin resistance are poorly understood in parasitic helminths. This reflects significant uncertainty regarding the mode of action of ivermectin in parasitic helminths, and the genetic complexity of these organisms; parasitic helminths have large, rapidly evolving genomes and differences in evolutionary history and genetic background can confound comparisons between resistant and susceptible populations. We undertook a controlled genetic cross of a multi-drug resistant and a susceptible reference isolate of Haemonchus contortus, an economically important gastrointestinal nematode of sheep, and ivermectin-selected the F2 population for comparison with an untreated F2 control. RNA-seq analyses of male and female adults of all populations identified high transcriptomic differentiation between parental isolates, which was significantly reduced in the F2, allowing differences associated specifically with ivermectin resistance to be identified. In all resistant populations, there was constitutive upregulation of a single gene, HCON_00155390:cky-1, a putative pharyngeal-expressed transcription factor, in a narrow locus on chromosome V previously shown to be under ivermectin selection. In addition, we detected sex-specific differences in gene expression between resistant and susceptible populations, including constitutive upregulation of a P-glycoprotein, HCON_00162780:pgp-11, in resistant males only. After ivermectin selection, we identified differential expression of genes with roles in neuronal function and chloride homeostasis, which is consistent with an adaptive response to ivermectin-induced hyperpolarisation of neuromuscular cells. Overall, we show the utility of a genetic cross to identify differences in gene expression that are specific to ivermectin selection and provide a framework to better understand ivermectin resistance and response to treatment in parasitic helminths.

From COVID-19 Treatment to Miracle Cure

From COVID-19 Treatment to Miracle Cure

A device to simulate contaminant transfer and surface and subsurface flow through intact soil monoliths

AbstractMany contaminants of agricultural origin are released into rural environments, particularly at the soil surface. Their fate has been extensively investigated in repacked soils, but only few studies have addressed their transport in structurally preserved natural soils. Much remains unknown about their fate and transfer within and between environmental compartments, while the susceptibility of these compartments to the contaminants adverse effects can vary considerably. The lack of studies regarding surface and subsurface transfer of contaminants through intact soil compared with studies on repacked soil led us to propose a device and protocol for sampling intact soil monoliths (60 × 30 × 22 cm3, length, width, depth [LWD]) without heavy machinery. This is achieved by a modular design with removable top and bottom lid and a protocol of cutting the soil and replacing the affected bottom soil with a drainage layer of glass beads. The device allows the application of artificial rainfall events with simultaneous highly resolved quantification of infiltration excess overland flow and drainage discharge. It is designed to facilitate the collection of samples for physical, biological, and chemical analyses that fulfill cleanliness standards for organic contaminant analysis at trace levels using only poorly reactive stainless steel and glass materials. Testing of the device was performed by measuring the transfer of the antiparasitic drug ivermectin (IVM) through and over a silt‐loam pasture soil. This test case illustrates how the device can be used to gain valuable information on the transfer of trace organic contaminants through topsoils.

Drug utilization pattern of hospitalized patients with COVID-19 in a tertiary care center

Background: The first COVID-19 case was reported in a Chinese province named Wuhan in December 2019, which later spread to 215 countries worldwide infecting 47.9 crores of people and caused 61.1 lakhs of deaths, until March 2022. In India alone, 4.3 crores were infected and 5.17 lakhs deaths were reported until the above said period. Aims and Objectives: In this study, we analyze the drug utilization pattern of mainline and supportive drugs used in the treatment of COVID-19 patients admitted in a tertiary care center. The role of repurposed drugs in the prescription pattern of COVID-19 patients would also be analyzed. Materials and Methods: The study included all the COVID-19 patients admitted in this institution between April 2021 and June 2021. These included patients were laboratory-confirmed positive cases and must have received medical treatment for a minimum of 3 days in the hospital. Pregnant women and children admitted with COVID-19 infection were not included in this study. All the data for this study were retrospectively extracted from the medical records department of the institution. A total of 420 patients have been admitted in COVID-19 ward between April 2021 and June 2021, out of which 300 case records which fulfilled the above said criteria were selected for further scrutiny. Results: Among 300 patients, there were 192 males (64%) admitted with COVID-19 infection compared to 108 females (36%). Predominant age group of distribution of COVID-19 cases was between 50 and 60 years (42%). One hundred and eighty-eight COVID-19 cases had one or more comorbid conditions along with COVID-19 infection. There were 12 deaths among the selected 300 cases during their hospital stay. The most common combination used in the treatment of COVID-19 was an antibacterial, antiviral, antithrombotic, and an anti-inflammatory drug. About 76% (n = 228) of the admitted COVID-19 patients received this combination along with other supportive or symptomatic treatment during the stay in hospital. About 88% (n = 284) of cases had an antiparasitic drug ivermectin in a daily dose of 12 mg for a period of 5 days. Ivermectin is one among the repurposed drugs used in the treatment of COVID-19 infection. Proton-pump inhibitors such as omeprazole 20 mg twice daily in oral route or pantoprazole 40 mg in parenteral route were the supportive drugs used in most prescriptions. Conclusion: Except the high empirical usage of antibiotics, the remaining frontline drugs for COVID-19 such as antiviral, corticosteroids, and antithrombotics were utilized in an appropriate manner. A high positive clinical outcome observed in this study can be attributed to the expertise gained by the physicians over the period of time in handling the COVID-19 infection.

DDRE-07. TARGETING TUMOR HYPOXIA AND MITOCHONDRIAL METABOLISM WITH ANTI-PARASITIC DRUGS AS AN APPROACH TO IMPROVE THE RADIOSENSITIVITY OF DIFFUSE INTRINSIC PONTINE GLIOMA

Abstract Diffuse intrinsic pontine glioma (DIPG) is an incurable pediatric brain tumor with a median survival of 12 months. Current management is limited to radiotherapy; however, the tumor recurs secondary to radioresistance. Tumor hypoxia appears to be one of the major contributors to radioresistance of DIPG, as oxygenation is critical to successful radiotherapy treatment. Therefore, strategies to alleviate hypoxia could enhance the effectiveness of radiotherapy and result in improved survival outcomes of patients with DIPG. Recent approaches to target tumor hypoxia are predicated on inhibiting mitochondrial respiration of the tumors to decrease oxygen consumption rate (OCR) and increase oxygenation. Here, we aimed to identify a safe but potent mitochondrial inhibitor that could decrease OCR and hypoxia, and improve the radiosensitivity of DIPG. A subset of anti-parasitic drugs (atovaquone, ivermectin, quinacrine, mefloquine and proguanil) which are known mitochondrial inhibitors were studied against a panel of patient-derived DIPG cell lines. We assessed their antiproliferative effects, OCR inhibition and radiosensitising efficacy using cell proliferation, extracellular flux and colony formation assays. Among the five tested drug candidates, atovaquone was found to be the most potent OCR inhibitor with minimal antiproliferative effects on DIPG cultures. It also decreased hypoxia in 3-dimensional DIPG neurospheres, reduced the expression of hypoxia-inducible factor-1α and improved the radiosensitivity of neurospheres of DIPG. Its anti-mitochondrial role was further confirmed by inhibition of various mitochondrial parameters and increase in reactive oxygen species. Overall, these results provide promising in vitro evidence of atovaquone as a hypoxia modifier and radiosensitiser in DIPG and pave a way for rapid translation to in vivo studies.

Effects of Ivermectin in Patients With COVID-19: A Multicenter, Double-blind, Randomized, Controlled Clinical Trial

PurposeGiven the coronavirus disease 2019 (COVID-19) pandemic, there is a global urgency to discover an effective treatment for patients withthis disease. This study aimed to evaluate the effects of the widely used antiparasitic drug ivermectin on outcomes in patients with COVID-19. MethodsIn this randomized, double-blind clinical trial, patients with COVID-19 admitted to 2 referral tertiary hospitals in Mazandaran, Iran, were randomly divided into 2 groups: intervention and control. In addition to standard treatment for COVID-19, the intervention group received a single weight-based dose (0.2 mg/kg) of ivermectin; the control group received the standard of care. Demographic, clinical, laboratory, and imaging data from participants were recorded at baseline. Patients were assessed daily for symptoms and disease progression. The primary clinical outcome measures were the durations of hospital stay, fever, dyspnea, and cough; and overall clinical improvement. FindingsSixty-nine patients were enrolled (mean [SD] ages: ivermectin, 47.63 [22.20] years; control, 45.18 [23.11] years; P = 0.65). Eighteen patients (51.4%) in the ivermectin group and 18 (52.9%) in control group were male (P = 0.90). The mean durations of dyspnea were 2.6 (0.4) days in the ivermectin group and 3.8 (0.4) days in the control group (P = 0.048). Also, persistent cough lasted for 3.1 (0.4) days in the ivermectin group compared to 4.8 (0.4) days in control group (PP = 0.019). The mean durations of hospital stay were 7.1 (0.5) days versus 8.4 (0.6) days in the ivermectin and control groups, respectively (P = 0.016). Also, the frequency of lymphopenia decreased to 14.3% in the ivermectin group and did not change in the control group (P = 0.007). ImplicationsA single dose of ivermectin was well-tolerated in symptomatic patients with COVID-19, and important clinical features of COVID-19 were improved with ivermectin use, including dyspnea, cough, and lymphopenia. Further studies with larger sample sizes, different drug dosages, dosing intervals and durations, especially in different stages of the disease, may be useful in understanding the potential clinical benefits ivermectin. Iranian Registry of Clinical Trials identifier: IRCT20111224008507N3.

Use of the Anti-Parasitic Drug Ivermectin to Treat Breast Cancer

Use of the Anti-Parasitic Drug Ivermectin to Treat Breast Cancer

Ivermectin converts cold tumors hot and synergizes with immune checkpoint blockade for treatment of breast cancer

We show that treatment with the FDA-approved anti-parasitic drug ivermectin induces immunogenic cancer cell death (ICD) and robust T cell infiltration into breast tumors. As an allosteric modulator of the ATP/P2X4/P2X7 axis which operates in both cancer and immune cells, ivermectin also selectively targets immunosuppressive populations including myeloid cells and Tregs, resulting in enhanced Teff/Tregs ratio. While neither agent alone showed efficacy in vivo, combination therapy with ivermectin and checkpoint inhibitor anti-PD1 antibody achieved synergy in limiting tumor growth (p = 0.03) and promoted complete responses (p < 0.01), also leading to immunity against contralateral re-challenge with demonstrated anti-tumor immune responses. Going beyond primary tumors, this combination achieved significant reduction in relapse after neoadjuvant (p = 0.03) and adjuvant treatment (p < 0.001), and potential cures in metastatic disease (p < 0.001). Statistical modeling confirmed bona fide synergistic activity in both the adjuvant (p = 0.007) and metastatic settings (p < 0.001). Ivermectin has dual immunomodulatory and ICD-inducing effects in breast cancer, converting cold tumors hot, thus represents a rational mechanistic partner with checkpoint blockade.

The effect of ivermectin alone and in combination with cobicistat or elacridar in experimental Schistosoma mansoni infection in mice

Schistosoma mansoni is less susceptible to the antiparasitic drug ivermectin than other helminths. By inhibiting the P-glycoprotein or cytochrome P450 3A in mice host or parasites in a murine model, we aimed at increasing the sensitivity of S. mansoni to the drug and thus preventing infection. We assigned 124 BALB/c mice to no treatment, treatment with ivermectin only or a combination of ivermectin with either cobicistat or elacridar once daily for three days before infecting them with 150 S. mansoni cercariae each. The assignment was done by batches without an explicit randomization code. Toxicity was monitored. At eight weeks post-infection, mice were euthanized. We determined number of eggs in intestine and liver, adult worms in portal and mesenteric veins. Disease was assessed by counting granulomas/cm2 of liver and studying organ weight indices and total weight. IgG levels in serum were also considered. No difference between groups treated with ivermectin only or in combination with cobicistat or elacridar compared with untreated, infected controls. Most mice treated with ivermectin and elacridar suffered severe neurological toxicity. In conclusion, systemic treatment with ivermectin, even in the presence of pharmacological inhibition of P-glycoprotein or cytochrome P450 3A, did not result in effective prophylaxis for S. mansoni infection in an experimental murine model.

Ivermectin Accelerates Circulating Nonstructural Protein 1 (NS1) Clearance in Adult Dengue Patients: A Combined Phase 2/3 Randomized Double-blinded Placebo Controlled Trial

Dengue is the most significant mosquito-borne viral disease; there are no specific therapeutics. The antiparasitic drug ivermectin efficiently inhibits the replication of all 4 dengue virus serotypes in vitro. We conducted 2 consecutive randomized, double-blind, placebo-controlled trials in adult dengue patients to evaluate safety and virological and clinical efficacies of ivermectin. After a phase 2 trial with 2 or 3 days of 1 daily dose of 400 µg/kg ivermectin, we continued with a phase 3, placebo-controlled trial with 3 days of 400 µg/kg ivermectin. The phase 2 trial showed a trend in reduction of plasma nonstructural protein 1 (NS1) clearance time in the 3-day ivermectin group compared with placebo. Combining phase 2 and 3 trials, 203 patients were included in the intention to treat analysis (100 and 103 patients receiving ivermectin and placebo, respectively). Dengue hemorrhagic fever occurred in 24 (24.0%) of ivermectin-treated patients and 32 (31.1%) patients receiving placebo (P = .260). The median (95% confidence interval [CI]) clearance time of NS1 antigenemia was shorter in the ivermectin group (71.5 [95% CI 59.9-84.0] hours vs 95.8 [95% CI 83.9-120.0] hours, P = .014). At discharge, 72.0% and 47.6% of patients in the ivermectin and placebo groups, respectively had undetectable plasma NS1 (P = .001). There were no differences in the viremia clearance time and incidence of adverse events between the 2 groups. A 3-day 1 daily dose of 400 µg/kg oral ivermectin was safe and accelerated NS1 antigenemia clearance in dengue patients. However, clinical efficacy of ivermectin was not observed at this dosage regimen.

Microscopic interactions between ivermectin and key human and viral proteins involved in SARS-CoV-2 infection.

The identification of chemical compounds able to bind specific sites of the human/viral proteins involved in the SARS-CoV-2 infection cycle is a prerequisite to design effective antiviral drugs. Here we conduct a molecular dynamics study with the aim to assess the interactions of ivermectin, an antiparasitic drug with broad-spectrum antiviral activity, with the human Angiotensin-Converting Enzyme 2 (ACE2), the viral 3CLpro and PLpro proteases, and the viral SARS Unique Domain (SUD). The drug/target interactions have been characterized in silico by describing the nature of the non-covalent interactions found and by measuring the extent of their time duration along the MD simulation. Results reveal that the ACE2 protein and the ACE2/RBD aggregates form the most persistent interactions with ivermectin, while the binding with the remaining viral proteins is more limited and unspecific.

THE USE OF ANTIPARASITIC DRUGS AS A TREATMENT FOR COVID-19: A NARRATIVE REVIEW

Objetive: Describe research related to the use of antiparasitic drugs as likely treatment in COVID-19 based on scientific literature. Methods: This is a literature review that uses two platforms as a database: Pubmed and BIREME. Were included in this study twelve published articles, from 2019 to September 2020, which referred to or were related to the use of antiparasitic drugs as a therapeutic alternative to COVID-19. Results: The antiparasitic drugs ivermectin, hydroxychloroquine (HQC), and nitazoxanide (NTZ) were the main drugs extensively studied as therapeutic alternatives for SARS-CoV-2. Ivermectin exhibited a 5000-fold reduction in SARS-CoV-2 RNA over a 48h period, at a concentration of 5μM. While HQC was able to block the entry of SARS-Cov-2 into Vero cells previously treated with 50μM. In addition, NTZ, presented an average inhibition concentration (EC50) of 2.12 μM. The mechanisms of anti-SARS-CoV-2 actions of all the drugs mentioned are not yet fully elucidated. However, it is known that the antiviral potential may be related to the inhibition of essential viral proteins (ivermectin), blockade of interaction in virus-host (HTZ), and immunosuppressant (NTZ). Conclusion: The use of antiparasitic agents for the treatment of SARS-CoV-2 have shown promise. However, it is necessary to further investigate the efficacy of the drugs mentioned in this study, to obtain more satisfactory results, seeking to avoid adverse effects on patients, and ensuring safety for them.

Safety and efficacy of ivermectin in times of COVID-19

Since its appearance in December 2019, the SARS-CoV-2 infection spread rapidly to the whole world. About 80 % of COVID-19 patients have mild to moderate symptoms, 20 % develop severe respiratory symptoms, and about 6 % may require mechanical ventilation. In the absence of clinically proven treatment guidelines, several well-known drugs began to be evaluated in clinical trials for their likely benefits in the treatment of COVID-19. Among them is the antiparasitic drug ivermectin, one of the avermactins produced by the bacterium Streptomyces avermitilis, discovered in the seventies by Professor Omura's group in collaboration with the pharmaceutical industry. Ivermectin has been shown to inhibit the interaction between viral protein and importin α/β1 heterodimer, leading to inhibition of viral replication. This mechanism of action of ivermectin against SARS-CoV-2 was recently demonstrated in Vero/hSLAM cells. To date, theresults of a clinical trial conducted in Argentina that prove the usefulness of ivermectin in the early stages of the disease are known. In addition, around 40 clinical studies, which seek to confirm the importance of ivermectin as a cost-effective treatment for COVID-19, are registered worldwide. Regarding its safety, ivermectin has proven to be a well-tolerated drug over the years.

Pathophysiology and Potential Therapeutic Candidates for COVID-19: A Poorly Understood Arena.

Coronavirus disease 2019 (COVID-19), an acute onset pneumonia caused by a novel Betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in the Wuhan City of China in December 2019 and evolved into a global pandemic. To date, there are no proven drugs or vaccines against this virus. Hence, the situation demands an urgent need to explore all potential therapeutic strategies that can be made available to prevent the disease progression and improve patient outcomes. In absence of clinically proven treatment guidelines, several repurposed drugs and investigational agents are currently being evaluated in clinical trials for their probable benefits in the treatment of COVID-19. These include antivirals (remdesivir, lopinavir/ritonavir, umifenovir, and favipiravir), interferon, antimalarials (chloroquine/hydroxychloroquine), antiparasitic drugs (ivermectin and nitazoxanide), biologics (monoclonal antibodies and interleukin receptor antagonist), cellular therapies (mesenchymal stem cells and natural killer cells), convalescent plasma, and cytokine adsorber. Though several observational studies have claimed many of these agents to be effective based on their in vitro activities and extrapolated evidence from SARS and Middle East respiratory syndrome (MERS) epidemics, the currently available data remains inconclusive because of ill-defined patient selection criteria, small sample size, lack of concurrent controls, and use of intermediary outcomes instead of patient-relevant outcomes. Moreover, there is a need to clearly define the patient populations who warrant therapy and also the timing of initiation of treatment. Understanding the disease pathology responsible for the clinical manifestations of COVID-19 is imperative to identify the potential targets for drug development. This review explains the pathophysiology of COVID-19 and summarizes the potential treatment candidates, which can provide guidance in developing effective therapeutic strategies.