Formestane is a second generation, irreversible, steroidal aromatase inhibitor. It inhibits the aromatase enzyme responsible for converting androgens to estrogens, thereby preventing estrogen production.
Breast cancer may be estrogen sensitive or insensitive. A majority of breast cancers are estrogen sensitive.
Estrogen sensitive breast cancer cells depend on estrogen for viability. Thus removal of estrogen from
the body can be an effective treatment for hormone sensitive breast cancers.
Formestane has been targeted specifically for the treatment of postmenopausal women.