December 14, 2009 (San Antonio, Texas) — New results coming from 2 mature
trials with exemestane (Aromasin, Pfizer) suggest that this aromatase inhibitor differs slightly from the other 2 available products, letrozole (Femara, Novartis) and anastrozole (Arimidex, AstraZeneca).
Although all 3 are aromatase inhibitors, exemestane is a steroidal product that binds irreversibly to the estrogen receptor; the other 2 products are both nonsteroidal and are reversible inhibitors.