Single Dose of a Small Molecule Leads to Complete Regressions of Large Breast Tumors in Mice.

Patients with estrogen receptor α positive (ERα+) breast cancer typically undergo surgical resection, followed by 5-10 years of treatment with adjuvant endocrine therapy. This prolonged intervention is associated with a host of undesired side effects that reduce patient compliance, and ultimately therapeutic resistance and disease relapse/progression are common. An ideal anticancer therapy would be effective against recurrent and refractory disease with minimal dosing; however, there is little precedent for marked tumor regression with a single dose of a small molecule therapeutic.