Estrogen Receptor-positive Breast Cancer

Each year, approximately 250,000 women are diagnosed with breast cancer in the United States alone. 70-80% of patients have breast cancers in which the tumor cells express estrogen receptors (ER) that drive proliferation. These women are often treated with endocrine therapies that target ER signaling, both for metastatic breast cnacer, and for adjuvant use for the prevention of recurrence of early breast cancer.


Olema Pharmaceuticals, Inc. is developing a new class of drugs for the treatment of ER-positive breast cancer: Pure Antagonist - Selective Estrogen Receptor Degraders (PA-SERDs). These drugs are designed to both completely inactivate and degrade ER, and to be taken as a daily, oral pill.

Olema's OP-1250

Olema's lead compound OP-1250 is a potent, oral PA-SERD. OP-1250 blocks estrogen-driven transcription and proliferation, and degrades the estrogen receptor in human breast cancer cells in culture. OP-1250 shrinks partially tamoxifen-resistant human breast cancer tumors in a mouse xenograft model, even at low doses.

Olema intends to take OP-1250 into human clinical studies in 2018.