Nintedanib-13C,d3 is a 13C- and deuterium-labeled version of Nintedanib. Nintedanib (BIBF 1120) is a potent triple angiokinase inhibitor that effectively blocks VEGFR1/2/3, FGFR1/2/3, and PDGFRα/β with IC50 values of 34 nM/13 nM/13 nM, 69 nM/37 nM/108 nM, and 59 nM/65 nM, respectively.