Kinase activity inhibition curve of SAF-189s against ROS1 (a), ROS1G2032R (b), and ROS1L2026M (c). d IC50 values of SAF-189s, lorlatinib, ceritinib, and crizotinib against the kinase activity of ROS1 and a series of crizotinib-resistant mutants. e SAF-189s functions in an ATP-competitive manner to inhibit ROS1 kinases. The values shown in Fig.1 represent the mean ± SD.