• Phase I study (N = 40) of crizotinib in ROS1-rearranged NSCLC
• ORR of 60%
• The toxicity profile of crizotinib for patients with ROS1-positive NSCLC was similar to that for patients with ALK-positive NSCLC

ROS1 rearrangements are even less common than ALK alterations, and this report builds on the initial work of Dr Alice Shaw and colleagues (also presented in this monograph) by clearly demonstrating that more than half of patients in this trial experienced objective tumor responses to crizotinib. As might be expected, the side-effect profile was not different for patients with ROS1-positive tumors. Of course, the FDA has yet to endorse crizotinib for these individuals, and it seems certain that oncologists will rapidly turn to this important data set as they attempt to obtain permission/reimbursement not only for additional testing but also for crizotinib for patients with tumors containing a ROS1 rearrangement.