Exemestane

Status

FDA-approved. FDA-approved labeling exists as Aromasin for adjuvant treatment of postmenopausal women with oestrogen receptor-positive early breast cancer following tamoxifen, and for advanced disease. No approved indication in men.

What it is

An oral aromatase inhibitor that binds the enzyme irreversibly.

What published research measured

A steroidal aromatase inhibitor that inactivates the enzyme irreversibly, in contrast to the reversible binding of anastrozole and letrozole. Randomized trials in breast cancer, including the IES trial and the MAP.3 prevention trial, establish its efficacy in that setting. Because it is a steroid it has mild androgenic properties of its own, which some literature suggests slightly moderates the effect on bone compared with the non-steroidal agents, though it does not eliminate it. Use in men is off-label with no supporting outcome data, and the same principle applies as for the rest of the class: the goal of oestrogen suppression in a man is moderation, and these drugs are designed to achieve near-complete blockade.

Source

IES trial · MAP.3 prevention trial · FDA labeling for Aromasin

Sources

• Half-life source for Exemestane