RMC-5127 is an oral and mutation-selective inhibitor of RASG12V (ON) that inhibits the GTP-bound (ON) form of RAS G12V through the formation of a high-affinity triplex with central nervous system (CNS) permeability and brain permeability. RMC-5127 inhibits RAS pathway activity in vitro in KRAS G12V mutant human cancer cells and cellular proliferation, and antitumor activity in preclinical intracranial xenograft models and subcutaneous CDX and PDX models of KRAS G12V mutant NSCLC, PDAC and CRC.