Exemestane (trade name Aromasin) is a drug used to treat breast cancer. It is a member of the class of drugs known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers have estrogen receptors (ERs) and are called ER-positive. They may also be called estrogen-responsive hormonally-responsive or hormone-receptor-positive.

For R&D use onlynot for drug household or other uses.

Exemestane is a steroidal antiestrogen and irreversible aromatase inhibitor. Exemestane acts as a false substrate for the aromatase enzyme. Exemestane also prevents the conversion of androgens to estrogens and is used to treat estrogen-dependent breast cancer.