Vandetanib (ZD6474) in the Treatment of Medullary Thyroid Cancer

Vandetanib (ZD6474) is an orally bioavailable small molecule tyrosine kinase inhibitor of multiple growth factor receptors, including RET (Rearrange during transfection), vascular endothelial growth factor receptor-2 (VEGFR-2) and epidermal growth factor receptor (EGFR). The activity against RET and VEGF made it a good choice in the treatment of medullary thyroid cancer (MTC). As there is considerable cross talk between growth factor pathways, dual inhibition with such agents has become an attractive strategy, in the treatment of many malignancies with encouraging Phase II clinical trial data to date. Vandetanib was tested in two Phase II trials in the treatment of patients with medullary thyroid cancer at doses of 100 mg and 300 mg daily respectively. The encouraging results of these 2 trials led to a randomized phase II trial comparing this medication to placebo using a crossover design. More than 300 patients were included in this study, which ultimately showed a significant improvement in progression-free survival in patients taking vandetanib. Based on these results, the Oncology Drug Advisory Committee (ODAC) of the Food and Drug Administration (FDA) recommended that vandetanib be approved for the treatment of patients with unresectable locally advanced or metastatic medullary thyroid cancer.