Data from Resistance Profile and Structural Modeling of Next-Generation ROS1 Tyrosine Kinase Inhibitors

Abstract

<div>Abstract<p>ROS1 fusion proteins resulting from chromosomal rearrangements of the <i>ROS1</i> gene are targetable oncogenic drivers in diverse cancers. Acquired resistance to targeted inhibitors curtails clinical benefit and response durability. Entrectinib, a NTRK/ROS1/ALK targeted tyrosine kinase inhibitor (TKI), was approved for the treatment of ROS1 fusion-positive non–small cell lung cancer (NSCLC) in 2019. In addition, lorlatinib and repotrectinib are actively being explored in the setting of treatment-naïve or crizotinib-resistant ROS1 fusion driven NSCLC. Here, we employed an unbiased forward mutagenesis screen in Ba/F3 CD74-ROS1 and EZR-ROS1 cells to identify resistance liabilities to entrectinib, lorlatinib, and repotrectinib. ROS1<sup>F2004C</sup> emerged as a recurrent entrectinib resistant mutation and ROS1<sup>G2032R</sup> was discovered in entrectinib and lorlatinib-resistant clones. Cell-based and modeling data show that entrectinib is a dual type I/II mode inhibitor, and thus liable to both types of resistant mutations. Comprehensive profiling of all clinically relevant kinase domain mutations showed that ROS1<sup>L2086F</sup> is broadly resistant to all type I inhibitors, but remains sensitive to type II inhibitors. ROS1<sup>F2004C/I/V</sup> are resistant to type I inhibitors, entrectinib and crizotinib, and type II inhibitor, cabozantinib, but retain sensitivity to the type I macrocyclic inhibitors. Development of new, more selective type II ROS1 inhibitor(s) or potentially cycling type I and type II inhibitors may be one way to expand durability of ROS1-targeted agents.</p></div>