First patient enrolled in clinical study with the fetal estrogen estetrol (E4) in patients with advanced breast cancer (the ABCE4 study)

The first patient has been enrolled in the Phase I/II clinical trial assessing safety and efficacy of estetrol (E4) in postmenopausal women with advanced ER+ breast cancer. The study is a multi-center, open-label, dose-escalation study with a 3 + 3 cohort design to determine the recommended dose of E4 for the treatment of patients with advanced breast cancer. In total 9-18 patients will be enrolled at three centers in Germany.

The main objectives of this study are to evaluate the safety, the effects on estrogen deficiency symptoms and the preliminary anti-tumor activity of E4 in patients with advanced breast cancer.