Targeting Estrogen Receptor Activation in Breast Cancer
New therapies for patients with endocrine-resistant ER-positive breast cancer.
The Problem
Endocrine therapy combined with CDK4/6 inhibitors has transformed treatment of ER-positive breast cancer, but most patients eventually stop responding. In many of these tumors the estrogen receptor remains active, and current therapies do not fully address how it is switched on.
Our Approach
PhosphoERx is a preclinical-stage company founded to develop small-molecule therapies that act on the estrogen receptor in a new way, building on research published in Nature (2025) that defined how the receptor is activated. Our goal is to give patients whose disease has progressed on current therapies a new, biomarker-guided treatment option.
Founder: Sichun Yang, PhD
Contact: For partnering, investment, or scientific inquiries: sichun@phosphoerx.com
Our programs are in preclinical development and are not available for patient use or clinical trials at this time.