favipiravir   Click here for help

GtoPdb Ligand ID: 11139

Synonyms: T-705 | T705
Approved drug
favipiravir is an approved drug (China and Japan)
Compound class: Synthetic organic
Comment: Favipiravir (T-705) is an orally delivered, guanine (purine) analogue antiviral drug (cf. remdesivir which is administered i.v.). It targets viral RNA-dependent RNA polymerase (RdRP) of RNA viruses and since the catalytic domain of RdRP is well conserved across species, has a broad-spectrum of activity; although Furuta et al. (2002) reported that actvity was weak against non-influenza virus RNA viruses [4]. Favipiravir was originally identified through a chemical library screen against influenza virus RdRP [3]. Chemically, it is a prodrug. In human cells it undergoes phosphoribosylation and phosphorylation to its active form, favipiravir-ribofuranosyl-5′-triphosphate (F-RTP). F-RTP is bound by the RdRP, but it blocks enzyme activity and so terminates chain elongation [5-6].
2D Structure
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2D Structure

An image of the ligand's 2D structure. For small molecules with SMILES these are drawn using the NCI/CADD Chemical Identifier Resolver. Click on the image to access the chemical structure search tool with the ligand pre-loaded in the structure editor. For other types of ligands, e.g. longer nucleotides and peptides, a manually drawn representation of the molecule may be provided.

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Physico-chemical Properties
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Physico-chemical Properties

Calculated molecular properties are available for small molecules and natural products (not peptides). Properties were generated using the CDK toolkit. All properties were selected to enable the prediction of the Lipinski Rule-of-Five profile or ‘druglikeness’ for each ligand. For more info on each category see the help pages.

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Hydrogen bond acceptors 3
Hydrogen bond donors 2
Rotatable bonds 1
Topological polar surface area 88.84
Molecular weight 157.03
XLogP -0.35
No. Lipinski's rules broken 0
SMILES / InChI / InChIKey
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SMILES / InChI / InChIKey

SMILES (Simplified Molecular Input Line Entry Specification) A specification for unambiguously describing the structure of chemical molecules using short ASCII strings. Canonical SMILES specify a unique representation of the 2D structure without chiral or isotopic specifications. Isomeric SMILES include chiral specification and isotopes.

Standard InChI (IUPAC International Chemical Identifier) and InChIKey InChI is a non-proprietary, standard, textual identifier for chemical substances designed to facilitate linking of information and database searching. An InChIKey is a simplified version of a full InChI, designed for easier web searching.

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Canonical SMILES Fc1c[nH]c(=O)c(n1)C(=O)N
Isomeric SMILES Fc1c[nH]c(=O)c(n1)C(=O)N
InChI InChI=1S/C5H4FN3O2/c6-2-1-8-5(11)3(9-2)4(7)10/h1H,(H2,7,10)(H,8,11)
InChI Key ZCGNOVWYSGBHAU-UHFFFAOYSA-N
No information available.
Summary of Clinical Use Click here for help
Oral favipiravir is already approved in China and Japan to treat influenza, and Phase 3 trials for influenza are underway in the US.

SARS-CoV-2 and COVID-19: a number of clinical trials have been launched globally, to evaluate the safety and efficacy of favipiravir in COVID-19 patients. favipiravir is used to treat COVID-19 in Russia and India under emergency use approvals.

With respect to emergent RNA viruses with future epidemic/pandemic potential [2], favipiravir has shown efficacy in the hamster model of Nipah virus infection [1]. It also has some activity against Ebola virus [7], and evidence of activity in a guinea pig Lassa virus infection model [8].

Click here to link to the full list of favipiravir studies at ClinicalTrials.gov.
Clinical Trials
Clinical Trial ID Title Type Source Comment References
NCT04425460 A Multi-center,Randomized,Double-blind,Placebo-controlled,Phase 3 Study Evaluating Favipiravir in Treatment of COVID19 Phase 3 Interventional Zhejiang Hisun Pharmaceutical Co. Ltd.
NCT04358549 Study of the Use of Favipiravir in Hospitalized Subjects With COVID-19 Phase 2 Interventional Fujifilm Pharmaceuticals U.S.A., Inc.
NCT02329054 Efficacy of Favipiravir Against Ebola (JIKI) Phase 2 Interventional Institut National de la Santé Et de la Recherche Médicale, France
NCT04402203 Study on Safety and Efficacy of Favipiravir (Favipira) for COVID-19 Patient in Selected Hospitals of Bangladesh Phase 2/Phase 3 Interventional Bangladesh Medical Research Council (BMRC)
NCT04373733 Early Intervention in COVID-19: Favipiravir Verses Standard Care Phase 3 Interventional Chelsea and Westminster NHS Foundation Trust