What is exemestane?
Exemestane (Aromasin) is a third-generation aromatase inhibitor used to treat hormone responsive breast cancers in women who are postmenopausal – have gone through menopause.
Some breast cancer cells need the hormone estrogen to grow. Exemestane works by blocking the enzyme aromatase, which converts androgen hormones into estrogen.
In premenopausal women the main source of estrogen is the ovaries. But in postmenopausal women, the main source of estrogen is from the conversion of androstenedione and testosterone – adrenal and ovarian androgen hormones – by the enzyme aromatase.
Exemestane is an irreversible, steroidal aromatase inactivator that works by binding to and and inactivating aromatase, an effect that is known as ‘suicide inhibition’. This prevents aromatase from converting androgens into estrogen and cuts of the supply of estrogen that the breast cancer cells need to grow.
Exemestane was first approved by the US Food and Drug Administration (FDA) and in 1999 and marketed under the brand name Aromasin. Aromasin tablets are still available, but generic exemestane tablets have also been available for more than a decade.
