Clinical Overview of Anastrozole A New Selective Oral Aromatase Inhibitor

The efficacy and tolerability of the new selective aromatase inhibitor, anastrozole (Arimidex®), was compared with megestrol acetate in the treatment of advanced breast cancer in postmenopausal women. In two independent prospective randomised trials, patients who progressed after prior tamoxifen therapy received anastrozole 1 or 10 mg once daily, or megestrol acetate, 40 mg q.i.d. The two studies were designed to allow the data to be combined to increase the statistical power of the analyses. It is the data from these combined analyses that are considered in further detail. After 6 months of follow-up, the proportion of patients gaining clinical benefit (complete response + partial response + stable disease ≥ 24 weeks) was approximately one third of patients in all three groups. No significant difference was observed between either dose of anastrozole and megestrol acetate in the time to disease progression (130–153 days). All three treatments were generally well tolerated, but significantly more patients on megestrol acetate gained weight, and the weight gain in this group continued up to at least 9 months of follow-up. At a 12-month update of tolerability, of the commonly observe