Discovery of BI-2493, a Pan-KRAS Inhibitor Showing <i>In Vivo</i> Efficacy

KRAS is one of the most highly validated cancer targets. Here we describe the design and synthesis of two reversible pan-KRAS inhibitors, BI-2865 and BI-2493. From our KRASG12C inhibitor program, we identified BI-2865, a potent noncovalent KRAS inhibitor that showed cellular activity against a broad spectrum of KRAS alleles and selectivity against HRAS and NRAS. Spirocyclization led to the discovery of BI-2493, a highly rigid analogue exhibiting better potency, metabolic stability, and permeability. BI-2493 shows in vivo efficacy in various KRAS mutant and KRAS wild-type amplified xenograft models and represents a promising starting point for further optimization.