Preclinical and Clinical Studies of Breast Cancer Prevention with Transdermal Anti-Progesterone Agents

Our goal continues to be the development of safer, more effective approaches for breast cancer prevention. BCRF support enables us to focus on drugs that oppose the actions of the female hormone progesterone, which have potential for breast cancer prevention, and possibly therapy. We have completed laboratory analysis of samples from the first-ever study of an anti-progesterone drug (telapristone) in women with early stage breast cancer; participants took either telapristone or placebo, while they awaited breast surgery. Results from this trial will be available shortly. Data developed with BCRF support enabled us to obtain funding for a recently opened second study funded by the National Cancer Institute. We are testing telapristone taken by mouth, or as a gel applied to the breast skin, to see if skin application will produce sufficient quantities of drug in the breast gland for breast cancer prevention and DCIS therapy. Low circulating levels should reduce side effects, improving tolerability and acceptance by high risk healthy women. If true, we will be able to develop this and other drugs for breast cancer prevention using gels applied to the breast skin. Finally, BCRF supported laboratory studies are allowing us to evaluate if breast tissue from BRCA1/2 carriers will respond to anti-progesterone drugs in a way that predicts successful breast cancer prevention in these very high risk women. These studies in the clinic and laboratory should lead to new options for breast cancer prevention which are safer, more effective, or both.