Vandetanib-d6 is the deuterium labeled Vandetanib. Vandetanib (D6474) is a potent, orally active inhibitor of VEGFR2/KDR tyrosine kinase activity (IC50=40 nM). Vandetanib also has activity versus the tyrosine kinase activity of VEGFR3/FLT4 (IC50=110 nM) and EGFR/HER1 (IC50=500 nM)[1].