Treatment of advanced breast cancer with formestane.

A total of 147 postmenopausal or postoophorectomy patients with advanced breast cancer resistant to standard endocrine therapies were treated with the potent aromatase inhibitor formestane (Lentaron). Among those available for assessment (n = 143), 32 (22%) had a partial response, while another 28 (20%) had stabilization of previously progressive disease. Patients responded to formestane irrespective of whether they had responded to, or failed to respond to, tamoxifen, medroxyprogesterone acetate, aminoglutethimide and trilostane. Toxicity was minimal. We conclude that formestane is an effective and non-toxic therapeutic agent for the treatment of women with advanced breast cancer.