Abstract:Clinical studies have demonstrated the antitumor efficacy of covalent KRAS G12C inhibitors in treating advanced/metastatic cancers. In the current study, we report the preclinical characteristics of a specific KRAS p.G12C covalent inhibitor, glecirasib. Glecirasib exhibited high potency against KRAS G12C, along with a high level of selectivity over wild-type KRAS, HRAS, and NRAS in biochemical assays. On the cellular level, it substantially reduced downstream ERK and AKT phosphorylation, inhibited the viability of cancer cells harboring the KRAS p.G12C mutation, and demonstrated high selectivity over non-KRAS p.G12C cancer cells. Glecirasib could effectively inhibit HRAS G12C, NRAS G12C, and several G12C-inclusive KRAS double mutants that showed resistance to adagrasib. In vivo research suggested that once-daily dosing of glecirasib can robustly inhibit ERK phosphorylation for at least 24 hours and induced tumor regression in several xenograft models, including the NCI-H1373–luciferase intracranial model. Glecirasib in combination with cetuximab or JAB-3312 (sitneprotafib, a clinical-stage SHP2 inhibitor developed by Jacobio Pharma) significantly enhanced antitumor activity both in vitro and in vivo. Collectively, these results suggest that glecirasib is a potent and selective covalent inhibitor of KRAS G12C, shows potent antitumor activity as monotherapy, and synergizes with either EGFR blockade or SHP2 inhibition. A new drug application for glecirasib has been submitted in China, seeking approval for the treatment of non–small cell lung cancer, supported by a pivotal phase II single-arm study (NCT05009329). Additionally, glecirasib is being explored in clinical trials in combination with cetuximab (phase II, NCT05194995) and JAB-3312 (phase III, NCT06416410).
Significance::Glecirasib potently and selectively inhibits KRAS G12C and reduces ERK and AKT phosphorylation in KRAS G12C–mutant cancer cells, further inducing cell-cycle arrest and apoptosis. Glecirasib monotherapy leads to tumor regression in KRAS G12C–mutant animal models and shows synergistic effects with cetuximab or JAB-3312 (sitneprotafib).