...biopsy was performed, and the pathologic report showed a poorly differentiated lung adenocarcinoma with ROS1 rearrangement identified by immunohistochemical staining (clone: D4D6; H-score: 280) and further confirmative fluorescence in situ hybridization....The patient received ceritinib, 450 mg/day, and his tumor and brain and bone metastatic lesions subsequently decreased in size. The ceritinib was then shifted to crizotinib, 500 mg/day, when the reimbursement of crizotinib as a first-line therapy was approved by Taiwan's National Health Insurance system....In this case, while the patient’s dry cough was not severe, he decided to halt his crizotinib use. He further refused steroid use and asked to resume the ceritinib treatment. His dry cough improved substantially, and the lung consolidation lesion subsequently decreased (Figure, B).