In a phase 2 study (NCT03037385) including MTC patients with documented radiological progression, 122 patients with RET-mutant MTC (61 patients pre-treated with cabozantinib or vandetanib, or both, and 23 treatment-naïve patients) showed an overall objective radiological response rate of 71% (95% CI: 48–89) by RECIST criteria in treatment-naive patients and 60% (95% CI: 46–73) in pre-treated patients (Subbiah et al. 2018b). The gene discussed is RET; the disease is medullary thyroid gland carcinoma.