Effect of targeting FAK by ifebemtinib and immunogenic cell death of Kras G12C/G12D inhibition on the efficacy of PD1 blockade.

e15102 Background: Focal adhesion kinase (FAK) is one major component of focal adhesion complex and is important in regulating cancer cell survival. Previously, we found that a clinical-stage FAK inhibitor, ifebemtinib (aka IN10018) can overcome drug resistance of Kras G12C inhibitors by down regulating the FAK-YAP signaling. Combination of Kras G12Ci and FAKi has demonstrated encouraging efficacy in NSCLC. Here, we reported that targeting Kras G12D by selective Kras G12Di can also be enhanced by ifebemtinib. Further, Kras G12C inhibition plus PD1 blockade has demonstrated clinical benefits in PD-L1 high expression patient population, but ≈30% of patients experienced early disease progression; this might be attributed to loss-of-function of LKB1 and others. Immunogenic cell death (ICD) of Kras inhibition is enhanced by ifebemtinib, ICD reportedly enhances anti-PD1 activity. Thus, Kras inhibition and PD1 blockade plus ifebemtinib may be an ideal combination for patients with Kras G12D. Methods: Cell killing and apoptosis assays were performed to test the combination of Kras G12D inhibition and ifebemtinib. FACs analysis evaluated exposure levels vs. ICD biomarkers. The mice inoculated with CRC GP2D and PDAC PC-07-0013 were used for evaluating the combinational effects of Kras G12Di and ifebemtinib. The tumor bearing mice with Kras G12D mutant/LKB1 loss, NSCLC KPL, and CRC CT26 with knock-in Kras G12C were used for testing the effects of Kras inhibition, ifebemtinib, and PD1 blockade. Results: Ifebemtinib enhances the drug effects of Kras G12D inhibition in vitro and in vivo. The dual regimen of ifebemtinib and Kras inhibition outperformed either monotherapy with significant ICD induction in vitro (calreticulin/GRP94 exposure). The triple regimen of Kras inhibition, FAK inhibition and PD1 blockade exhibited stronger anti-cancer effects compared to the other related therapies, especially in a Kras G12D mutant, LKB1 loss animal model which is intrinsically resistant to PD1 blockade/Kras G12D inhibition. Conclusions: We discovered that targeting FAK by ifebemtinib enhances the anti-cancer effects of Kras G12D inhibition. It promotes ICD by targeting Kras G12D or G12C, further primes the dual regimen of Kras inhibition and ifebemtinib towards a response to anti PD1 therapy. The preclinical results warrant a further evaluation in the clinic.