ROS1 and non-small cell lung carcinoma: However, several studies have found that ROS1‐positive NSCLC patients appeared to be sensitive to pemetrexed‐based treatment.26, 27 Drilon et al28 reported that ROS1‐positive patients who were treated with pemetrexed‐based chemotherapy had good ORR (78%) and long PFS (23 months), which were higher than our study.