A randomised study of CGS 16949A (fadrozole) versus tamoxifen in previously untreated postmenopausal patients with metastatic breast cancer

Abstract

Fadrozole, a potent, highly specific inhibitor of aromatase activity, has only been used as second-line therapy in treatment of post-menopausal women with advanced breast cancer. A prospectively randomised study was therefore undertaken to compare relative clinical efficacy of fadrozole as first-line treatment to that of tamoxifen. Eighty postmenopausal women who had not received prior treatment for advanced/metastatic breast cancer were randomised to receive either fadrozole, 1 mg twice daily, or tamoxifen, 20 mg daily. Toxicity was not statistically different on the two treatment arms. Only mild to moderate toxicity was documented: hot flashes in 37%, headaches in 6.5%, mild fatigue in 2.6%. There were also no statistically significant differences in objective response rates, survival or time to treatment failure (TTF). Objective response rate on fadrozole was 50% (complete response (CR) 8.3% and partial response (PR) 42%). On tamoxifen objective response was 44.7% (CR 21% and PR 24%). Median TTF was 4.9 months on fadrozole and 5 months on tamoxifen. Median survival was 22.7 months on fadrozole and 27.5 months on tamoxifen. While response rates, survival and TTF were not statistically significantly different, there were more complete responses on tamoxifen and duration of objective response (CR + PR) was significantly longer in the patients treated with tamoxifen.