Abstract 2204: Novel FAK/ALK/ROS1 inhibitor APG-2449 synergizes with osimertinib in preclinical xenograft models of EGFR-mutant NSCLC

Abstract Focal adhesion kinase (FAK) plays an important role in cell migration, growth factor signaling, cell cycle progression and cellular survival. It had been shown that FAK and SRC family kinases were able to sustain downstream AKT and MAPK signaling under continuous EGFR inhibition driven by osimertinib (AZD9291), a mutant-selective third-generation EGFR inhibitor. Incomplete inhibition of AKT and MAPK was consistently observed even under increased concentrations of osimertinib and led to acquired resistance to osimertinib, implicating the need of combination therapy with FAK/SRC inhibitors to enhance antitumor activity of osimertinib and overcome its resistance. APG-2449 is a novel oral active small-molecular inhibitor that targets FAK, ALK and ROS1. In this study, we investigated the effect of combination treatment with APG-2449 and osimertinib using NSCLC NCI-H1975 cells carrying EGFRL858R/T790M mutation and an osimertinib-resistant patient-derived xenograft (PDX) model carrying EGFRT790M/19del/C797S mutation. In vitro, the combination treatment with APG-2449 and osimertinib synergistically inhibited the proliferation of NCI-H1975 cells. In vivo, APG-2449 significantly enhanced antitumor activity of osimertinib in NCI-H1975 xenograft models, leading to complete or partial tumor regression. More profound antitumor activity of this combination was also demonstrated in the osimeritinib-resistant PDX model in comparison with single agents. In term of mechanism, the combination arm significantly suppressed the on-target phosphorylation of EGFR, FAK and SRC, as well as AKT and ERK in NCI-H1975 xenografts. Collectively, these results suggest that addition of APG-2449 to osimeritinib may enhance antitumor activity and suppress the development of resistance in NSCLC. Citation Format: Guangfeng Wang, Douglas D. Fang, Ping Min, Ran Tao, Chunyang Tang, Shoulai Gu, Li Rui, Jiajun Li, Jingwen Wang, Miaoyi Wu, Yingfeng Li, Dingxiong Chen, Fei Zhang, Kejie Lian, Feifei Zhang, Lvcheng Wang, Rongcheng Xu, Dajun Yang, Yifan Zhai. Novel FAK/ALK/ROS1 inhibitor APG-2449 synergizes with osimertinib in preclinical xenograft models of EGFR-mutant NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2204.