A First-in-Class Progesterone Receptor Antagonist
ABOUT HORMONE DRIVEN CANCERS
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.
ROLE OF PR IN CANCER
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.
RESOURCES & PUBLICATIONS
- 1L mBCa Phase 2 Trial: Onapristone, a progesterone receptor antagonist, as first-line therapy in primary breast cancer
- 2L mBCa Phase 2 Trial: Onapristone in tamoxifen-resistant disease
- 3L+ PR+ Cancers: Phase I study of onapristone, a type I antiprogestin, in female patients with previously treated recurrent or metastatic PR-expressing cancers
- SABCS 2018: Apristor enhances the anti-proliferative effects of Cdk4/6 inhibitors and fulvestrant in preclinical in vitro breast cancer models
- MOA Review: Progesterone action in breast, uterine, and ovarian cancers
- Gyn Cancer Review: The Role of Hormonal Therapy in Gynecological Cancers
- Uterine Cancer: Inhibiting Nuclear PR Enhances Antitumor Activity of Onapristone in Uterine Cancer
- Cell Cycle: Cyclin D1 Enhances the Response to Progesterone By Regulating Progesterone Receptor Expression
- Immune Regulation: Interferon-Stimulated Genes Are Transcriptionally Repressed by PR in Breast Cancer
- DNA Repair: BRCA1 Counteracts Progesterone Action