Will the Requirement by the US FDA to Simultaneously Co-Develop Companion Diagnostics (CDx) Delay the Approval of Receptor Tyrosine Kinase Inhibitors for RTK-Rearranged (ROS1-, RET-, AXL-, PDGFR-α-, NTRK1-) Non-Small Cell Lung Cancer Globally? The gene discussed is NTRK1; the disease is non-small cell lung carcinoma.