Selective Estrogen Receptor Modulators (SERMs)
GTx has pioneered the use of a selective estrogen receptor modulator, or SERM, in men. A SERM is a small molecule nuclear hormone receptor modulator that binds to and selectively modulates estrogen receptors – acting either as an estrogen or an antiestrogen – depending on the target tissue, dose, gender and hormone levels.
In its most advanced clinical programs, GTx is developing toremifene citrate, a selective estrogen receptor modulator, or SERM, in two separate clinical programs in men: first, a completed pivotal Phase III clinical trial evaluating toremifene 80 mg to reduce the risk of fractures in men with prostate cancer on androgen deprivation therapy (ADT), and second, an ongoing pivotal Phase III clinical trial evaluating toremifene 20 mg for the prevention of prostate cancer in high risk men with high grade prostatic intraepithelial neoplasia, or PIN.
Estrogen plays a critical role in men’s health, promoting bone strength, maintaining cholesterol levels and regulating certain pituitary and central nervous system functions. However, in some tissues such as the prostate, a shift in the balance between estrogen and testosterone may promote benign prostatic hyperplasia (BPH) and cancer.
SERMS such as toremifene exhibit estrogenic activity in bone, lipids and the hypothalamus-pituitary axis and antiestrogenic effects in prostate and breast.
