Is Fulvestrant a chemotherapy drug?

Fulvestrant is not a chemotherapy drug, but an endocrine therapy drug. It belongs to a class of drugs called estrogen receptor antagonists. Fulvestrant is primarily used to treat breast cancer, especially those with estrogen receptor-positive breast cancer. Unlike chemotherapy drugs, fulvestrant works by acting on estrogen receptors in breast cancer cells. It blocks the binding of estrogen to receptors, thereby inhibiting the growth and spread of tumor cells. Fulvestrant is not a chemotherapy drug by itself, although it may be used in combination with other chemotherapy drugs in some cases.