Anticancer activity of RAS-GTP inhibition in cholangiocarcinoma [Mouse_hKPR.KPCHR_Sep25]

About 25% of cholangiocarcinoma (CCA) patients harbor KRAS mutations, being potentially amenable to direct KRAS inhibitors. Here, we investigated the activity of RAS(ON) multi-selective inhibitors, which target the active, GTP-bound state of both mutant and wild-type variants of canonical RAS isoforms, in CCA preclinical models and patients. RAS(ON) multi-selective inhibitors yield strong anticancer responses in cell- and patient-derived xenografts and in immunocompetent allograft models. Consistently, we describe responses to the RAS(ON) multi-selective inhibitor daraxonrasib in two KRASG12X patients with advanced CCA. RAS-GTP inhibition also potentiates the activity of the current standard-of-care CCA therapy to prolong survival in cell-derived human xenografts and mouse allografts. Furthermore, we demonstrate that both intrinsic and acquired resistance to RAS(ON) multi-selective inhibitors mainly rely on reconstitution of RAS signalling. Overall, our findings indicate that KRAS mutant CCA is addicted to RAS signalling for proliferation and support the potential clinical evaluation of RAS-GTP inhibition in CCA.