Activity and Safety of the Antiestrogen EM-800, the Orally Active Precursor of Acolbifene, in Tamoxifen-Resistant Breast Cancer

Abstract

EM-800 produced responses in a significant proportion of patients with tamoxifen-resistant breast cancer, thus showing that this highly potent, selective estrogen receptor modulator, which lacks estrogenic activity in the mammary gland and endometrium, has incomplete cross-resistance with tamoxifen, thus suggesting additional benefits in the treatment of breast cancer.