Fulvestrant +/- Vandetanib in Advanced Aromatase Inhibitor Resistant Breast Cancer

The pharmacology and mode of action studies established that fulvestrant is the first agent in a new class of anti-estrogens that down-regulate the estrogen receptor (ER), and can therefore be described as an ER down-regulator.

Vandetanib is a potent inhibitor of the tyrosine kinase activity of vascular endothelial growth factor receptor (VEGFR; also known as kinase insert domain containing receptor)-2, an endothelial cell receptor for vascular endothelial growth factor (VEGF), and also possesses activity against epidermal growth factor receptor (EGFR) and Rearranged during Transfection (RET) tyrosine kinases.