In their phase I/II study, Wirth et al. (2020) revealed a 69% response rate in patients with RET-variant MTC who had undergone prior treatment with vandetanib or cabozantinib and a 73% response rate in patients with no prior TKI therapy history when treated with selpercatinib. The gene discussed is RET; the disease is medullary thyroid gland carcinoma.