Q3 · MEDICINE
Article
Author: Vinogradova, Maia ; Yeap, Kuen ; Chang, Jae ; Friedman, Lori S. ; Mody, Vidhi ; Roussel, Fabien ; Nannini, Michelle ; Otwine, Daniel ; Zheng, Xiaoping ; Liang, Jun ; Labadie, Sharada ; Wai, John ; Blake, Robert ; Zhang, Birong ; Liao, Jiangpeng ; Wang, Tao ; Ran, Yingqing ; Kiefer, James R. ; Sampath, Deepak ; Li, Jun ; Goodacre, Simon ; Wang, Xiaojing ; Ingalla, Ellen Rei ; Young, Amy ; Ray, Nick ; Hartman, Steven ; Lai, Kwong Wah ; McLean, Neville ; Zhong, Yu ; Kleinheinz, Tracy ; Zbieg, Jason ; Sambrone, Amy ; Metcalfe, Ciara
Estrogen receptor alpha (ERα) is a well-validated drug target for ER-positive (ER+) breast cancer. Fulvestrant is FDA-approved to treat ER+ breast cancer and works through two mechanisms-as a full antagonist and selective estrogen receptor degrader (SERD)-but lacks oral bioavailability. Thus, we envisioned a "best-in-class" molecule with the same dual mechanisms as fulvestrant, but with significant oral exposure. Through lead optimization, we discovered a tool molecule 12 (GNE-149) with improved degradation and antiproliferative activity in both MCF7 and T47D cells. To illustrate the binding mode and key interactions of this scaffold with ERα, we obtained a cocrystal structure of 6 that showed ionic interaction of azetidine with Asp351 residue. Importantly, 12 showed favorable metabolic stability and good oral exposure. 12 exhibited antagonist effect in the uterus and demonstrated robust dose-dependent efficacy in xenograft models.