Pfizer, a global pharmaceutical giant headquartered in New York City, NY announced that the FDA has granted Breakthrough Therapy designation to its oncology drug XALKORI® (crizotinib) for the potential treatment of patients with ROS1-positive non-small cell lung cancer (NSCLC). XALKORI is a small-molecule tyrosine kinase inhibitor of anaplastic lymphoma kinase (ALK), ROS1, and another proto-oncogene receptor tyrosine kinase, MET. It currently is approved in the U.S. for the treatment of patients with ALK-positive metastatic NSCLC. ALK status can be determined by an FDA-approved test. ROS1-positive NSCLC represents a particular molecular subgroup of NSCLC and clinical studies have shown that XALKORI exhibited antitumor activities in this group of patients. NSCLC is a heterogeneous disease and the coupling of XALKORI treatment with companion diagnostic tests further showcase the importance of precision medicine.