Abstract 4794: Preclinical evaluation of WX-0593, a potent orally active ALK inhibitor

Abstract Objective: ALK is a tyrosine kinase belonging to the insulin receptor super-family. The constitutively active ALK fusions are oncogenic and linked with multiple types of human cancer. The EML4-ALK fusion has been proven to be the driver of approximately 5% of NSCLC patients. We disclose here for the first time a novel ALK inhibitor WX-0593 and its preclinical evaluation data in preclinical models of ALK driven NSCLC. Method: The enzyme activities of WX-0593 for ALKWT, ALKL1196M, ALKC1156Y and EGFRL858R/T790M were measured with corresponding kinase assays. The anti-proliferative activity was evaluated in Karpas-299, Ba/F3, Ba/F3 (EML4-ALK-WT), Ba/F3 (EML4-ALK-L1196M), Ba/F3 (EML4-ALK-C1156Y), and NCI-H1975 cell lines. The specific effect (PD) of WX-0593 on ALK signaling was analyzed in NCI-H3122 cells. Antitumor activity of WX-0593 was evaluated in three patient-derived xenograft (PDX) models of NSCLC (LU-01-0015, LU-01-0319, and crizotinib resistant LU-01-0319R) and one cell-derived xenograft (CDX) model of NSCLC (NCI-H3122). PKPD was assessed by western blot analysis of the treated tumor tissues for p-ALK (Tyr1604), p-STAT3 (Tyr705), p-STAT5 (Tyr694), p-AKT, and p-ERK. Result: WX-0593 displayed potent enzymatic activities for ALKWT, ALKL1196M, ALKC1156Y and EGFRL858R/T790M with IC50 of 5.38, 9.26, 9.28, and 16.74 nM respectively. It also showed expected anti-proliferative activity in six cell lines, Karpas-299, Ba/F3, Ba/F3 (EML4-ALK-WT), Ba/F3 (EML4- ALK-L1196M), Ba/F3 (EML4-ALK-C1156Y), and NCI-H1975, with IC50 of 4.5, 2208, 4, 9.5, 9, and 508 nM, respectively. Western blot study in NCI-H3122 cells showed that WX-0593 could fully inhibit p-ALK, p-ERK,p-STAT5 at 11.1 nM and p-AKT at 100 nM. WX-0593 significantly inhibited tumor growth at all doses tested (P<0.001) in the LU-01-0015 (HIP1-ALK), LU-01-0319 (EML4-ALK), and LU-01-0319R NSCLC PDX models as well as in the NCI-H3122 CDX model. Western blot analysis of the tumor samples showed that WX-0593 inhibited p-ALK (Tyr1604), p-STAT3 (Tyr705), p-STAT5 (Tyr694), p-AKT, and p-ERK, indicating that the tumor growth inhibition was mediated by inhibition of ALK signaling. Conclusion: We have identified a potent orally active second generation ALK inhibitor, WX-0593. It can inhibit the activity of both wide type and crizotinib resistant ALK and showed strong antitumor activity in in vitro and in vivo preclinical models. These results are considered highly promising and warrant moving the compound forward to clinical investigation. Citation Format: Liu Xile, Charles Z Ding, Weifeng Mao, Yuxin Qin, Shansong Zheng, Yingying Yang, Qingmei Zheng, Long Zhang, Shuyong Zhao. Preclinical evaluation of WX-0593, a potent orally active ALK inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4794.