A retrospective analysis of PROFILE 1001, a phase 1 study of 53 ROS1‐ and 153 ALK‐rearranged non‐small cell lung cancer (NSCLC) patients showed that patients started on anticoagulation (as a possible surrogate for thrombosis) had a worse objective response rate and progression‐free survival with crizotinib than those not on anticoagulation. The gene discussed is ALK; the disease is non-small cell lung carcinoma.