Randomized trial of alternative dose regimens of exemestane in postmenopausal stage 0 to II ER-positive breast cancer

Succesful therapeutic cancer prevention requires definition of the minimal effective dose. Aromatase inhibitors decrease breast cancer incidence in high-risk women, but use in prevention and compliance in adjuvant settings are hampered by adverse events. A multinational randomized phase 2b study evaluated change in serum estradiol with exemestane 25 mg once daily versus three times weekly versus once weekly. Among compliant patients, the change in the three times weekly group was noninferior to the change in the once daily group, whereas the once-weekly schedule was less effective. Adverse events were similar in all arms (visual abstract).