Crizotinib in ROS1 rearranged non-small cell lung cancer (NSCLC), from response to resistance.

We examined an immediate, but short-lived, response to crizotinib, a drug with a new indication for ROS1 rearranged non-small cell lung cancer (NSCLC) in a middle-aged non-smoker. The patient presented with metastatic NSCLC and extensive disease in multiple organs. He was treated with crizotinib 250 mg twice a day. Within 2-3 days, his condition rapidly improved, which was evident in a CT scan 2 months later. However, after 3 months of treatment, his condition deteriorated dramatically. The patient did not respond to ceritinib, a second-line drug that targets anaplastic lymphoma kinase, and died shortly after. This case demonstrated an impressive but brief response to crizotinib.