ROS1 and cancer: Crizotinib,an ALK/ROS1/cMET inhibitor, achieved 72% objective response rate and19.2 months progression-free survival, and was the first TKI to receiveFDA and EMA approval for the treatment of advanced ROS1 fusion–positivelung cancer.4 A second multikinase inhibitor,Entrectinib, with intracranial activity against ROS1, ALK, and TRK,was approved for the treatment of metastatic ROS1-positive nonsmallcell lung cancer (ROS1+ NSCLC) based on data from an integrated efficacyanalysis of the STARTRK-1, STARTRK-2, and ALKA-372-001 clinical trials.5,6