Alternative Dosing of Exemestane Before Surgery in Treating Postmenopausal Patients With Stage 0-II Estrogen Positive Breast Cancer

This phase IIb trial studies how well alternative dosing of exemestane before surgery works in treating in postmenopausal patients with stage 0-II estrogen positive breast cancer. Chemoprevention is the use of drugs to keep breast cancer from forming or coming back. The use of exemestane may treat early stage (stage 0-II) breast cancer. Comparing the exemestane standard dose regimen versus two alternative, less frequent dose regimens may decrease undesirable symptoms and have similar efficacy in reducing serum estradiol.

We have conducted an international, multicenter, pre-surgical double-blind non-inferiority phase IIb study in which a total of 180 participants have been randomized to receive either exemestane 25 mg/day (Exemestane 25 mg QD) or 25 mg/ three times a week (Exemestane 25 mg TIW) or a single dose of 25 mg/week (Exemestane 25 mg QW) for a minimum of 4 up to 6 weeks. Participants were stratified by center and BMI (\<25 kg/m2 vs \>25 kg/m2). Participants were histologically confirmed ER-positive (ER \>10%) primary breast cancer patients who were candidates for breast surgery. Postmenopausal women younger than 76 years of age with cT0-2, cN0-1, Mx or women with larger tumors who refuse neo-adjuvant therapy before surgery were eligible. No previous treatment for breast cancer was allowed. Complete physical exam and safety lab tests have been performed at baseline and at the end of treatment (28+1, 35+1, 42+1 days). Phone contact occurred on day 1 and a week before surgery (+3 days). Participants experiencing persistent adverse events (certainly, probably, and possibly treatment-related) have been monitored 20-30 days after study completion. Biomarkers: blood samples were collected at baseline and the end of treatment (fasting blood for biomarkers collected prior to randomization and either on the day of surgery or the day before; fasting strongly recommended but not mandated), tissue samples collected from the diagnostic or research biopsy and at the time of surgery.