a Combination ASP2453 (1 nmol/L) with erlotinib (500 nmol/L) under EGF stimulation (0.1 ng/mL) inhibits the proliferation of KRAS G12C-mutated NCI-H358 cells in 3D spheroid culture (mean ± SD). b Anti-tumour activity of ASP2453 (10 mg/kg) in combination with erlotinib (100 mg/kg) in a subcutaneous NCI-H358 xenograft model (n = 5 mice per group, mean ± SEM). ***P < 0.01, ****P < 0.001, Dunnett’s multiple comparison test compared with vehicle. ††P < 0.01, two-tailed Student’s t-test compared with erlotinib-treated group. c Anti-tumour activity of ASP2453 in combination with anti-PD-1 antibody in a subcutaneous CT26.WT_mKRAS (p.G12C) (KI) syngeneic model (n = 5 mice per group, mean ± SEM).