BI-2493 was highly selective for KRAS and did not cause more than 30% inhibition in a panel of 404 kinases or 38 targets commonly used in safety profiling (Extended Data Fig. 10f,g, respectively). Last, the inhibitor attenuated tumour growth in mice bearing KRAS G12C, G12D, G12V and A146V mutant models (Fig. 4f), without causing apparent toxicity to the mice (at least as determined by monitoring animal weight).