Abstract 919: AZD3463, a novel ALK/IGF1R inhibitor, overcomes multiple mechanisms of acquired resistance to crizotinib.

Genomic rearrangement of Anaplastic Lymphoma Kinase (ALK) has been observed in several tumor types including 60-80% anaplastic large cell lymphoma (ALCL) and 3-6% of non small cell lung cancer (NSCLC). Although the ALK inhibitor crizotinib has clinical efficacy in selected ALK positive NSCLC patients, the majority of patients who show initial responses eventually relapse. Various mechanisms leading to resistance have been proposed and include ALK amplification and resistance mutations, as well as alternative pathway drivers including EGFR, cKIT and, more recently, IGF1R. We have discovered a novel and potent inhibitor of ALK, AZD3463 with a Ki value of 0.75nM which also inhibits additional receptor tyrosine kinases including insulin growth factor receptor (IGF1R) with equivalent potency. AZD3463 inhibits ALK in cells as demonstrated by its ability to decrease ALK autophosphorylation in tumor cell lines containing ALK fusions including DEL (ALCL NPM-ALK), H3122 (NSCLC EML4-ALK) and H2228 (NSCLC EML4-ALK). Inhibition of ALK is associated with perturbations in downstream signaling including ERK, AKT and STAT3 pathways leading to preferential inhibition of proliferation in the ALK fusion containing cell lines in vitro. AZD3463 also demonstrates the ability to dose dependently inhibit pALK in xenograft tumors in vivo resulting in stasis (H3122) or regression (DEL, H2228). AZD3463 retains good activity against a number of clinically relevant crizotinib resistant mutations including the gatekeeper mutant L1196M where equivalent potency to wild type ALK is observed in vitro and in vivo in EML4-ALK containing BAF3 cell lines. To further assess the potential ability of AZD3463 to overcome additional resistance mechanisms, antiproliferative activity was assessed in multiple crizotinib resistant cell lines independently derived in vitro from H3122 cells as well as a patient derived crizotinib relapsed model. These resistant cell lines contain multiple resistance mechanisms including the L1196M gatekeeper and T115Ins mutations, ALK amplification and/or secondary drivers including EGFR and IGF1R. AZD3463 retains antiproliferative potency within 4 fold of parental H3122 cells for 10 out of 12 of these acquired resistance models in vitro. In summary, AZD3463 is a potent ALK inhibitor which inhibits additional kinases including IGF1R and has activity in a number of crizotinib resistant models driven by multiple resistance mechanisms. Citation Format: Lisa Drew, Jane Cheng, Jeffrey Engelman, Douglas Ferguson, Ryohei Katayama, Brenda McDermott, Jamal Saeh, Alice Shaw, Minhui Shen, Dan Widzowski, Allan Wu, Graeme Smith. AZD3463, a novel ALK/IGF1R inhibitor, overcomes multiple mechanisms of acquired resistance to crizotinib. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 919. doi:10.1158/1538-7445.AM2013-919