Preclinical and clinical studies of breast cancer prevention with transdermal anti-progesterone agents

Lay Summmary: We have initiated the first-ever trial of an anti-progesterone medication in early-stage breast cancer patients with the goal of developing this group of drugs for breast cancer prevention and therapy (NCT08188422 clinical trials.gov). The trial is enrolling newly-diagnosed Stage I-II breast cancer patients who will take a daily dose of active drug placebo for 2-10 weeks, while they await surgical therapy. This trial will give us preliminary information about the ability of of this new class of drugs to decrease the growth rate of breast cancer cell and will pave the way for additional future studies, including those which test the possibility of using these drugs as a gel on the skin of the breast for breast cancer prevention. In parallel, we have conducted experients to show that these drugs effectivley block progesterone receptor, decrease the growth rate fo breast cancer cells in culture, and prevent progesterone-induced turmors in a rate model. We will now perform the additional laboratory studies that will help to identify the groups of women who will benefit most from this group of drugs.