MRTX849 ethoxypropanoic acid incorporates a ligand for KRAS G12C, and a PROTAC linker. MRTX849 ethoxypropanoic acid can be used in the synthesis of PROTAC LC-2. LC-2 is a potent and first-in-class PROTAC capable of degrading endogenous KRAS G12C ( IC 50 s between 0.25 and 0.76 μM).