SR16157: A Safer, More Effective Estrogen Inhibitor for Treating Breast Cancer

Breast cancer is the most common cancer among women in the U.S. and the second deadliest type of cancer in this population. Patients who are postmenopausal and have estrogen-dependent tumors frequently undergo a type of hormone therapy consisting of aromatase inhibitors (AIs), which block the production of estrogen. These drugs do not achieve ideal response rates, however, and they produce adverse side effects, such as osteoporosis, arthritis, and possibly cardiovascular problems, which lead to patient non-compliance.

As an alternative to AIs, SRI has developed an estrogen inhibitor called SR16157. This rationally designed drug achieves more complete estrogen suppression by inhibiting estrogen in two ways. SR16157 irreversibly inhibits steroid sulfatase, an enzyme that is crucial for estrogen biosynthesis in breast tumors, and by blocking estrogen receptors.

This orally administered drug substantially inhibits tumor growth in animal models of breast cancer, while protecting against bone loss and avoiding the cardiovascular side effects associated with AI treatment. Studies also indicate that its therapeutic benefits may extend to other estrogen-dependent cancers, such as endometrial and ovarian cancer. SR16157 shows promise for safely and effectively suppressing tumors, preventing relapse, and increasing overall survival in patients.

Learn more in the SR16157 product summary slides.