Regorafenib N-Demethyl-N-4-(3-fluoro-4-methylphenoxy)-N-methyl-d3-picolinamide is the labeled analogue of Regorafenib N-Demethyl-N-4-(3-fluoro-4-methylphenoxy)-N-methylpicolinamide (R143005), an impurity of Regorafenib (R143000), which inhibits PDGFR tyrosine kinase with IC50=83nM. It is useful for the treatment of inflammation and as an anti-proliferative agent.