Pharmacology and clinical experience with exemestane

Since the introduction of the first generation aromatase inhibitor, aminogl utethimide, for breast cancer treatment 30 years ago, we now have at hand n ovel, potent and well-tolerated steroidal and non-steroidal compounds, allo wing near complete inhibition of oestrogen synthesis. The third-generation aromatase inhibitor, or more accurately termed inactivator, exemestane, is a potent suppressor of oestrogen synthesis and is shown to be an effective antitumour agent in postmenopausal breast cancer patients. Exemestane has b een shown to be effective in patients failing multiple endocrine regimens. A large randomised study has revealed that exemestane improves time-to-dise ase progression as well as overall survival compared with megestrol acetate as second-line therapy in patients failing tamoxifen. In current studies, exemestane is compared with tamoxifen as first-line therapy for metastatic disease. Sequential therapy with tamoxifen followed by exemestane is also b eing compared with tamoxifen monotherapy in the adjuvant setting. In additi on, the drug may have potential for breast cancer prevention.