Population Pharmacokinetics and Exposure–Response Analysis for the Phase 3 COSMIC-311 Trial of Cabozantinib for Radioiodine-Refractory Differentiated Thyroid Cancer

Background and Objective In the USA, cabozantinib was approved for the treatment of patients aged ≥ 12 years with radioiodine-refractory differentiated thyroid cancer (DTC) who progressed on prior vascular endothelial growth factor (VEGFR)-targeted therapy based on the Phase 3 COSMIC-311 trial, which evaluated cabozantinib 60 mg/day versus placebo. Approved dosing is 60 mg/day for adults and for pediatric patients aged ≥ 12 years with body surface area (BSA) ≥ 1.2 m 2 , and 40 mg/day for pediatric patients aged ≥ 12 years with BSA