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Lane TR, Dyall J, Mercer L, Goodin C, Foil DH, Zhou H, Postnikova E, Liang JY, Holbrook MR, Madrid PB, Ekins S. Repurposing Pyramax®, quinacrine and tilorone as treatments for Ebola virus disease. Antiviral Res 2020; 182:104908. [PMID: 32798602 PMCID: PMC7425680 DOI: 10.1016/j.antiviral.2020.104908] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/03/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022]
Abstract
We have recently identified three molecules (tilorone, quinacrine and pyronaridine tetraphosphate) which all demonstrated efficacy in the mouse model of infection with mouse-adapted Ebola virus (EBOV) model of disease and had similar in vitro inhibition of an Ebola pseudovirus (VSV-EBOV-GP), suggesting they interfere with viral entry. Using a machine learning model to predict lysosomotropism these compounds were evaluated for their ability to possess a lysosomotropic mechanism in vitro. We now demonstrate in vitro that pyronaridine tetraphosphate is an inhibitor of Lysotracker accumulation in lysosomes (IC50 = 0.56 μM). Further, we evaluated antiviral synergy between pyronaridine and artesunate (Pyramax®), which are used in combination to treat malaria. Artesunate was not found to have lysosomotropic activity in vitro and the combination effect on EBOV inhibition was shown to be additive. Pyramax® may represent a unique example of the repurposing of a combination product for another disease.
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Affiliation(s)
- Thomas R Lane
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC, 27606, USA
| | - Julie Dyall
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA
| | - Luke Mercer
- Cambrex, 3501 Tricenter Blvd, Suite C, Durham, NC, 27713, USA
| | - Caleb Goodin
- Cambrex, 3501 Tricenter Blvd, Suite C, Durham, NC, 27713, USA
| | - Daniel H Foil
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC, 27606, USA
| | - Huanying Zhou
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA
| | | | - Janie Y Liang
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA
| | - Michael R Holbrook
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA
| | - Peter B Madrid
- SRI International, 333 Ravenswood Avenue, Menlo Park, CA, 94025, USA
| | - Sean Ekins
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC, 27606, USA.
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2
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Lane TR, Massey C, Comer JE, Freiberg AN, Zhou H, Dyall J, Holbrook MR, Anantpadma M, Davey RA, Madrid PB, Ekins S. Pyronaridine tetraphosphate efficacy against Ebola virus infection in guinea pig. Antiviral Res 2020; 181:104863. [PMID: 32682926 PMCID: PMC8194506 DOI: 10.1016/j.antiviral.2020.104863] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 12/22/2022]
Abstract
The recent outbreaks of the Ebola virus (EBOV) in Africa have brought global visibility to the shortage of available therapeutic options to treat patients infected with this or closely related viruses. We have recently computationally identified three molecules which have all demonstrated statistically significant efficacy in the mouse model of infection with mouse adapted Ebola virus (ma-EBOV). One of these molecules is the antimalarial pyronaridine tetraphosphate (IC50 range of 0.82-1.30 μM against three strains of EBOV and IC50 range of 1.01-2.72 μM against two strains of Marburg virus (MARV)) which is an approved drug in the European Union and used in combination with artesunate. To date, no small molecule drugs have shown statistically significant efficacy in the guinea pig model of EBOV infection. Pharmacokinetics and range-finding studies in guinea pigs directed us to a single 300 mg/kg or 600 mg/kg oral dose of pyronaridine 1hr after infection. Pyronaridine resulted in statistically significant survival of 40% at 300 mg/kg and protected from a lethal challenge with EBOV. In comparison, oral favipiravir (300 mg/kg dosed once a day) had 43.5% survival. All animals in the vehicle treatment group succumbed to disease by study day 12 (100% mortality). The in vitro metabolism and metabolite identification of pyronaridine and another of our EBOV active molecules, tilorone, suggested significant species differences which may account for the efficacy or lack thereof, respectively in guinea pig. In summary, our studies with pyronaridine demonstrates its utility for repurposing as an antiviral against EBOV and MARV.
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Affiliation(s)
- Thomas R. Lane
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
| | - Christopher Massey
- Institutional Office of Regulated Nonclinical Studies, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
| | - Jason E. Comer
- Institutional Office of Regulated Nonclinical Studies, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
- Department of Microbiology and Immunology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
| | - Alexander N. Freiberg
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555, USA
| | - Huanying Zhou
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA
| | - Julie Dyall
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA
| | - Michael R. Holbrook
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA
| | - Manu Anantpadma
- Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Robert A. Davey
- Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Peter B. Madrid
- SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, USA
| | - Sean Ekins
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
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Nascimento Junior JAC, Santos AM, Quintans-Júnior LJ, Walker CIB, Borges LP, Serafini MR. SARS, MERS and SARS-CoV-2 (COVID-19) treatment: a patent review. Expert Opin Ther Pat 2020; 30:567-579. [PMID: 32429703 DOI: 10.1080/13543776.2020.1772231] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Coronavirus has been responsible for several virus outbreaks since 2003, caused by SARS-CoV-1, MERS-CoV, and currently SARS-CoV-2 (COVID-19), the causative agent of coronavirus disease in 2019. COVID-19 has become a global public health emergency because of its high virulence and mortality capacity. This patent review aims to provide an overview of the patents that present possible treatments for SARS-CoV-1, SARS-CoV-2 and MERS-CoV. AREAS COVERED To treat SARS, MERS and SARS-CoV-2, researchers have filed patents for a number of therapeutic agents. Most of the treatments found were protease inhibitors aimed at proteases such as PLpro, 3 CLpro, RNA helicase, and Spike protein, or used monoclonal antibodies and interferons. In addition, the use of Chinese folk medicine and its multitude of medicinal plants with strong antiviral properties was reinforced. Thus, these therapies used in previous epidemics can serve as an aid in the new pandemic by SARS-CoV-2 and be a starting point for new treatments. EXPERT OPINION The various antiviral alternatives presented in this review offer therapeutic options to fight coronavirus infections. If shown to be effective, these drugs may be extremely important in the current pandemic.
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Affiliation(s)
- José Adão Carvalho Nascimento Junior
- Department of Pharmacy, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil.,Postgraduate Program in Pharmaceutical Sciences, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil
| | | | - Lucindo José Quintans-Júnior
- Department of Pharmacy, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil.,Postgraduate Program in Pharmaceutical Sciences, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil
| | - Cristiani Isabel Banderó Walker
- Department of Pharmacy, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil.,Postgraduate Program in Pharmaceutical Sciences, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil
| | - Lysandro Pinto Borges
- Department of Pharmacy, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil
| | - Mairim Russo Serafini
- Department of Pharmacy, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil.,Postgraduate Program in Pharmaceutical Sciences, Federal University of Sergipe , São Cristóvão, Sergipe, Brazil
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Ekins S, Mottin M, Ramos PRPS, Sousa BKP, Neves BJ, Foil DH, Zorn KM, Braga RC, Coffee M, Southan C, Puhl AC, Andrade CH. Déjà vu: Stimulating open drug discovery for SARS-CoV-2. Drug Discov Today 2020; 25:928-941. [PMID: 32320852 PMCID: PMC7167229 DOI: 10.1016/j.drudis.2020.03.019] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 12/16/2022]
Abstract
In the past decade we have seen two major Ebola virus outbreaks in Africa, the Zika virus in Brazil and the Americas and the current pandemic of coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There is a strong sense of déjà vu because there are still no effective treatments. In the COVID-19 pandemic, despite being a new virus, there are already drugs suggested as active in in vitro assays that are being repurposed in clinical trials. Promising SARS-CoV-2 viral targets and computational approaches are described and discussed. Here, we propose, based on open antiviral drug discovery approaches for previous outbreaks, that there could still be gaps in our approach to drug discovery.
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Affiliation(s)
- Sean Ekins
- Collaborations Pharmaceuticals, 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA.
| | - Melina Mottin
- LabMol - Laboratory of Molecular Modeling and Drug Design, Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO 74605-170, Brazil
| | - Paulo R P S Ramos
- LabMol - Laboratory of Molecular Modeling and Drug Design, Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO 74605-170, Brazil
| | - Bruna K P Sousa
- LabMol - Laboratory of Molecular Modeling and Drug Design, Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO 74605-170, Brazil
| | - Bruno Junior Neves
- LabMol - Laboratory of Molecular Modeling and Drug Design, Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO 74605-170, Brazil
| | - Daniel H Foil
- Collaborations Pharmaceuticals, 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
| | - Kimberley M Zorn
- Collaborations Pharmaceuticals, 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
| | | | - Megan Coffee
- Division of Infectious Diseases and Immunology, Department of Medicine, New York University, NY, USA; Department of Population and Family Health, Mailman School of Public Health, Columbia University, NY, USA
| | | | - Ana C Puhl
- Collaborations Pharmaceuticals, 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
| | - Carolina Horta Andrade
- LabMol - Laboratory of Molecular Modeling and Drug Design, Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO 74605-170, Brazil; Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, University of Campinas, Campinas, SP 13083-864, Brazil.
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Lane TR, Massey C, Comer JE, Anantpadma M, Freundlich JS, Davey RA, Madrid PB, Ekins S. Repurposing the antimalarial pyronaridine tetraphosphate to protect against Ebola virus infection. PLoS Negl Trop Dis 2019; 13:e0007890. [PMID: 31751347 PMCID: PMC6894882 DOI: 10.1371/journal.pntd.0007890] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/05/2019] [Accepted: 10/29/2019] [Indexed: 12/28/2022] Open
Abstract
Recent outbreaks of the Ebola virus (EBOV) have focused attention on the dire need for antivirals to treat these patients. We identified pyronaridine tetraphosphate as a potential candidate as it is an approved drug in the European Union which is currently used in combination with artesunate as a treatment for malaria (EC50 between 420 nM—1.14 μM against EBOV in HeLa cells). Range-finding studies in mice directed us to a single 75 mg/kg i.p. dose 1 hr after infection which resulted in 100% survival and statistically significantly reduced viremia at study day 3 from a lethal challenge with mouse-adapted EBOV (maEBOV). Further, an EBOV window study suggested we could dose pyronaridine 2 or 24 hrs post-exposure to result in similar efficacy. Analysis of cytokine and chemokine panels suggests that pyronaridine may act as an immunomodulator during an EBOV infection. Our studies with pyronaridine clearly demonstrate potential utility for its repurposing as an antiviral against EBOV and merits further study in larger animal models with the added benefit of already being used as a treatment against malaria. To date there is no approved drug for Ebola Virus infection. Our approach has been to assess drugs that are already approved for other uses in various countries. Using computational models, we have previously identified three such drugs and demonstrated their activity against the Ebola virus in vitro. We now report on the in vitro absorption, metabolism, distribution, excretion and pharmacokinetic properties of one of these molecules, namely the antimalarial pyronaridine. We justify efficacy testing in the mouse model of ebola infection. We also demonstrate that a single dose of this drug is 100% effective against the virus. This study provides important preclinical evaluation of this already approved drug and justifies its selection for larger animal efficacy studies.
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Affiliation(s)
- Thomas R. Lane
- Collaborations Pharmaceuticals, Inc., Raleigh, NC, United States of America
| | - Christopher Massey
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Jason E. Comer
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States of America
- Institutional Office of Regulated Nonclinical Studies, University of Texas Medical Branch, Galveston, TX, United States of America
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Manu Anantpadma
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, United States of America
| | - Joel S. Freundlich
- Departments of Pharmacology, Physiology, and Neuroscience & Medicine, Center for Emerging and Reemerging Pathogens, Rutgers University–New Jersey Medical School, NJ, United States of America
| | - Robert A. Davey
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, United States of America
| | | | - Sean Ekins
- Collaborations Pharmaceuticals, Inc., Raleigh, NC, United States of America
- * E-mail:
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6
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Anantpadma M, Lane T, Zorn KM, Lingerfelt MA, Clark AM, Freundlich JS, Davey RA, Madrid PB, Ekins S. Ebola Virus Bayesian Machine Learning Models Enable New in Vitro Leads. ACS OMEGA 2019; 4:2353-2361. [PMID: 30729228 PMCID: PMC6356859 DOI: 10.1021/acsomega.8b02948] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/17/2019] [Indexed: 05/08/2023]
Abstract
We have previously described the first Bayesian machine learning models from FDA-approved drug screens, for identifying compounds active against the Ebola virus (EBOV). These models led to the identification of three active molecules in vitro: tilorone, pyronaridine, and quinacrine. A follow-up study demonstrated that one of these compounds, tilorone, has 100% in vivo efficacy in mice infected with mouse-adapted EBOV at 30 mg/kg/day intraperitoneal. This suggested that we can learn from the published data on EBOV inhibition and use it to select new compounds for testing that are active in vivo. We used these previously built Bayesian machine learning EBOV models alongside our chemical insights for the selection of 12 molecules, absent from the training set, to test for in vitro EBOV inhibition. Nine molecules were directly selected using the model, and eight of these molecules possessed a promising in vitro activity (EC50 < 15 μM). Three further compounds were selected for an in vitro evaluation because they were antimalarials, and compounds of this class like pyronaridine and quinacrine have previously been shown to inhibit EBOV. We identified the antimalarial drug arterolane (IC50 = 4.53 μM) and the anticancer clinical candidate lucanthone (IC50 = 3.27 μM) as novel compounds that have EBOV inhibitory activity in HeLa cells and generally lack cytotoxicity. This work provides further validation for using machine learning and medicinal chemistry expertize to prioritize compounds for testing in vitro prior to more costly in vivo tests. These studies provide further corroboration of this strategy and suggest that it can likely be applied to other pathogens in the future.
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Affiliation(s)
- Manu Anantpadma
- Department
of Virology and Immunology, Texas Biomedical
Research Institute, 8715
West Military Drive, San Antonio, Texas 78227, United
States
| | - Thomas Lane
- Collaborations
Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Kimberley M. Zorn
- Collaborations
Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Mary A. Lingerfelt
- Collaborations
Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
| | - Alex M. Clark
- Molecular
Materials Informatics, Inc., 1900 St. Jacques #302, Montreal H3J 2S1, Quebec, Canada
| | - Joel S. Freundlich
- Departments
of Pharmacology, Physiology, and Neuroscience & Medicine, Center
for Emerging and Reemerging Pathogens, Rutgers
University—New Jersey Medical School, 185 South Orange Avenue, Newark, New Jersey 07103, United States
| | - Robert A. Davey
- Department
of Virology and Immunology, Texas Biomedical
Research Institute, 8715
West Military Drive, San Antonio, Texas 78227, United
States
| | - Peter B. Madrid
- SRI
International, 333 Ravenswood Avenue, Menlo Park, California 94025, United States
| | - Sean Ekins
- Collaborations
Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina 27606, United States
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Hernandez HW, Soeung M, Zorn KM, Ashoura N, Mottin M, Andrade CH, Caffrey CR, de Siqueira-Neto JL, Ekins S. High Throughput and Computational Repurposing for Neglected Diseases. Pharm Res 2018; 36:27. [PMID: 30560386 PMCID: PMC6792295 DOI: 10.1007/s11095-018-2558-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/09/2018] [Indexed: 12/21/2022]
Abstract
Purpose Neglected tropical diseases (NTDs) represent are a heterogeneous group of communicable diseases that are found within the poorest populations of the world. There are 23 NTDs that have been prioritized by the World Health Organization, which are endemic in 149 countries and affect more than 1.4 billion people, costing these developing economies billions of dollars annually. The NTDs result from four different causative pathogens: protozoa, bacteria, helminth and virus. The majority of the diseases lack effective treatments. Therefore, new therapeutics for NTDs are desperately needed. Methods We describe various high throughput screening and computational approaches that have been performed in recent years. We have collated the molecules identified in these studies and calculated molecular properties. Results Numerous global repurposing efforts have yielded some promising compounds for various neglected tropical diseases. These compounds when analyzed as one would expect appear drug-like. Several large datasets are also now in the public domain and this enables machine learning models to be constructed that then facilitate the discovery of new molecules for these pathogens. Conclusions In the space of a few years many groups have either performed experimental or computational repurposing high throughput screens against neglected diseases. These have identified compounds which in many cases are already approved drugs. Such approaches perhaps offer a more efficient way to develop treatments which are generally not a focus for global pharmaceutical companies because of the economics or the lack of a viable market. Other diseases could perhaps benefit from these repurposing approaches. Electronic supplementary material The online version of this article (10.1007/s11095-018-2558-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Melinda Soeung
- MD Anderson Cancer Center, University of Texas, Houston, Texas, USA
| | - Kimberley M Zorn
- Collaborations Pharmaceuticals Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina, 27606, USA
| | | | - Melina Mottin
- LabMol - Laboratory for Molecular Modeling and Drug Design Faculdade de Farmacia, Universidade Federal de Goias - UFG, Goiânia, GO, 74605-170, Brazil
| | - Carolina Horta Andrade
- LabMol - Laboratory for Molecular Modeling and Drug Design Faculdade de Farmacia, Universidade Federal de Goias - UFG, Goiânia, GO, 74605-170, Brazil
| | - Conor R Caffrey
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego, California, 92093, USA
| | - Jair Lage de Siqueira-Neto
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego, California, 92093, USA
| | - Sean Ekins
- Collaborations Pharmaceuticals Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina, 27606, USA.
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8
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Efficacy of Tilorone Dihydrochloride against Ebola Virus Infection. Antimicrob Agents Chemother 2018; 62:AAC.01711-17. [PMID: 29133569 DOI: 10.1128/aac.01711-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/24/2017] [Indexed: 11/20/2022] Open
Abstract
Tilorone dihydrochloride (tilorone) is a small-molecule, orally bioavailable drug that is used clinically as an antiviral outside the United States. A machine-learning model trained on anti-Ebola virus (EBOV) screening data previously identified tilorone as a potent in vitro EBOV inhibitor, making it a candidate for the treatment of Ebola virus disease (EVD). In the present study, a series of in vitro ADMET (absorption, distribution, metabolism, excretion, toxicity) assays demonstrated the drug has excellent solubility, high Caco-2 permeability, was not a P-glycoprotein substrate, and had no inhibitory activity against five human CYP450 enzymes (3A4, 2D6, 2C19, 2C9, and 1A2). Tilorone was shown to have 52% human plasma protein binding with excellent plasma stability and a mouse liver microsome half-life of 48 min. Dose range-finding studies in mice demonstrated a maximum tolerated single dose of 100 mg/kg of body weight. A pharmacokinetics study in mice at 2- and 10-mg/kg dose levels showed that the drug is rapidly absorbed, has dose-dependent increases in maximum concentration of unbound drug in plasma and areas under the concentration-time curve, and has a half-life of approximately 18 h in both males and females, although the exposure was ∼2.5-fold higher in male mice. Tilorone doses of 25 and 50 mg/kg proved efficacious in protecting 90% of mice from a lethal challenge with mouse-adapted with once-daily intraperitoneal (i.p.) dosing for 8 days. A subsequent study showed that 30 mg/kg/day of tilorone given i.p. starting 2 or 24 h postchallenge and continuing through day 7 postinfection was fully protective, indicating promising activity for the treatment of EVD.
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