A First-in-Class Progesterone Receptor Antagonist


Over 100,000 patients with metastatic breast, ovarian, prostate, or uterine cancers die per year in the United States. For many of these patients, continuous progesterone and estrogen signaling drives disease progression. Currently, only medicines that block estrogen are approved, meaning that progesterone signaling continues in those patients receiving anti-estrogen therapy.


Apristor (onapristone xr) is an investigational medicine that prevents progesterone signaling by blocking the interaction between progesterone and its binding partner, progesterone receptor. Apristor is the only known full PR antagonist. 


Under normal conditions, progesterone is primarily responsible for the development of sex organs and for regulating the menstrual cycle. Cancer cells hijack progesterone to stimulate cancer cell proliferation, metastases, regeneration, and immune evasion.



Fast-Follower, Oral Progesterone Receptor Antagonist

CTX-30916 is an Apristor analogue that exhibits unique pharmacological properties distinct from the parent compound. CTX-30916 may be developed across progesterone-driven diseases, including women’s health (endometriosis, uterine fibroids), rare disease (Charcot-Marie), or oncology.


Sigma1 Inhibitor

A First-In-Class Sigma1 Inhibitor For Abiraterone-Resistant Prostate Cancer

Sigma1 is an intracellular protein that engages in client protein complex formation to regulate the quality control, transport, and activity of client proteins.  By therapeutically modulating Sigma1 stabilization of client proteins, client protein transport is altered, leading to positive or negative regulation of client protein signaling pathways. Many of these client proteins are validated disease targets but are generally considered undruggable through small molecule approaches.  Indirect modulation of client protein stability and transport through Sigma1 expands the universe of opportunities for new drug discovery and new treatments for patients.

Sigma1 Research Consortium. 

Our strategy includes collaborating with academic and biopharmaceutical partners.  We have a flexible resource sharing program - our Sigma1 Toolkit - to enable the expedited transfer of our chemical library, reagents, and biomarker tools for groups interested in our core research areas and outside.