Using the trade name Masivet, this compound has been used for several years to treat mast cell tumours in dogs [6
]. It is a receptor tyrosine kinase (RTK) inhibitor, with inhibitory activity at the cKIT, platelet derived growth factor receptor (PDGFR) and fibroblast growth factor receptor (FGFR) RTKs [4
: Using X-ray crystallography, masitinib has been shown to bind (non-covalently) into the catalytic site of the SARS-CoV-2 3CL protease (Mpro) [3
], which corresponds with detection of in vitro
Mpro inhibitory activity. It does not bind to the other viral protease PLpro.