AMG 410 is a non-covalent, bimodal GDP (OFF) and GTP (ON)-binding pan-KRAS inhibitor with Kd (GDP) = 1 nM and Kd (GTP) = 22 nM, which enables circulation-independent blockade of KRAS. AMG 410 is more than 100-fold selective for KRAS than HRAS and NRAS2, binds on the same variegated pocket as KRAS G12C inhibitors, and has high potency in KRAS G12D, G12V, G12C, G13D and other mutants, IC 50 = 1-4 nM. AMG140 regresses tumors and reduces phosphorylated ERK levels in colorectal, pancreatic and lung models of KRAS mutations.