acolbifene hydrochloride
(ay-KOLE-bih-feen HY-droh-KLOR-ide)
A substance being studied in the prevention of breast cancer in women at high risk of breast cancer. Acolbifene hydrochloride binds to estrogen receptors in the body and blocks the effects of estrogen in the breast. It is a type of selective estrogen receptor modulator (SERM).