RET and medullary thyroid gland carcinoma: Selpercatinib is a small-molecule TKI targeting RET alterations (including mutations and fusions) [56] that was FDA-approved after the results from the LIBRETTO-001 trial, which included patients with RET-altered tumors, and showed encouraging activity in NSCLC and medullary thyroid carcinoma, as well as other cancers (among 45 patients with non-NSCLC or thyroid carcinoma the ORR was 43.9%, 95% CI 28.5–60.3%) [35,36,37].