Exposure of LUAD-0002AS1 (NSCLC, KIF5B–RET), ECLC5B (NSCLC, tripartite motif-containing 33 (TRIM33)–RET) and TT cells (medullary thyroid carcinoma, RETC634W) to vepafestinib resulted in efficient downregulation of RET phosphorylation at Y905 and Y1062 and downstream effectors. The gene discussed is KIF5B; the disease is non-small cell lung carcinoma.