Camostat mesylate inhibits SARS-CoV-2 activation by TMPRSS2-related proteases and its metabolite GBPA exerts antiviral activity

EBioMedicine. 2021 Mar:65:103255. doi: 10.1016/j.ebiom.2021.103255. Epub 2021 Mar 4.


Background: Antivirals are needed to combat the COVID-19 pandemic, which is caused by SARS-CoV-2. The clinically-proven protease inhibitor Camostat mesylate inhibits SARS-CoV-2 infection by blocking the virus-activating host cell protease TMPRSS2. However, antiviral activity of Camostat mesylate metabolites and potential viral resistance have not been analyzed. Moreover, antiviral activity of Camostat mesylate in human lung tissue remains to be demonstrated.

Methods: We used recombinant TMPRSS2, reporter particles bearing the spike protein of SARS-CoV-2 or authentic SARS-CoV-2 to assess inhibition of TMPRSS2 and viral entry, respectively, by Camostat mesylate and its metabolite GBPA.

Findings: We show that several TMPRSS2-related proteases activate SARS-CoV-2 and that two, TMPRSS11D and TMPRSS13, are robustly expressed in the upper respiratory tract. However, entry mediated by these proteases was blocked by Camostat mesylate. The Camostat metabolite GBPA inhibited recombinant TMPRSS2 with reduced efficiency as compared to Camostat mesylate. In contrast, both inhibitors exhibited similar antiviral activity and this correlated with the rapid conversion of Camostat mesylate into GBPA in the presence of serum. Finally, Camostat mesylate and GBPA blocked SARS-CoV-2 spread in human lung tissue ex vivo and the related protease inhibitor Nafamostat mesylate exerted augmented antiviral activity.

Interpretation: Our results suggest that SARS-CoV-2 can use TMPRSS2 and closely related proteases for spread in the upper respiratory tract and that spread in the human lung can be blocked by Camostat mesylate and its metabolite GBPA.

Funding: NIH, Damon Runyon Foundation, ACS, NYCT, DFG, EU, Berlin Mathematics center MATH+, BMBF, Lower Saxony, Lundbeck Foundation, Novo Nordisk Foundation.

Keywords: Camostat; FOY-251; GBPA; SARS-CoV-2; TMPRSS2.

MeSH terms

  • Animals
  • Antiviral Agents / pharmacology*
  • COVID-19 Drug Treatment*
  • Cell Line
  • Chlorocebus aethiops
  • Cricetinae
  • Esters / pharmacology*
  • Guanidines / pharmacology*
  • HEK293 Cells
  • Humans
  • Lung / pathology
  • Lung / virology
  • Membrane Proteins / biosynthesis
  • Molecular Dynamics Simulation
  • Protease Inhibitors / pharmacology*
  • SARS-CoV-2 / drug effects*
  • Serine Endopeptidases / biosynthesis
  • Serine Endopeptidases / metabolism*
  • Serine Proteases / biosynthesis
  • Vero Cells
  • Virus Activation / drug effects
  • Virus Internalization / drug effects


  • Antiviral Agents
  • Esters
  • Guanidines
  • Membrane Proteins
  • Protease Inhibitors
  • camostat
  • Serine Proteases
  • Serine Endopeptidases
  • TMPRSS11D protein, human
  • TMPRSS13 protein, human
  • TMPRSS2 protein, human