SHARE, The Metastatic Breast Cancer Network, and METAvivor sponsored a program in April on two new classes (or types) of drugs for women with advanced breast cancer: androgen blockers and drugs that inhibit the P13K pathway. As we know, there has been moderate success in developing life extending treatments for women with metastatic breast cancer. It is exciting when researchers strike out in innovative directions and SHARE is honored to have hosted the event. The presenters, both oncologists from Memorial Sloan Kettering, were Dr. Tiffany Traina, presenting information on the androgen blockers, and Dr. Maura Dickler, presenting information on agents that block the P13K pathway.
The two androgen blockers are Abiraterone (brand name Zytiga) and Enzalutamide (brand name Xtandi). Both drugs have already been approved for prostate cancer. Dr. Traina informed us that women produce androgen as well as men. Androgen in women is converted to estrogen. There is research in cell lines and animal models that blocking androgen receptors might be an effective way to control breast cancer cell growth. As Dr. Traina pointed out, almost 80% of all breast cancer cells have androgen receptors. It's important to note that androgen receptors appear in ER+ cells as well as triple negative and Her2 positive cells.
The trial for Enzalutamide is open to all women with advanced breast cancer who have already had two other treatments for metastatic breast cancer. Tests on tumor samples from women with triple negative disease have shown that those with androgen receptors (25%) behave like ER+ disease although they do not have ER or PR receptors.
The Abiraterone trial will be looking for which is more effective in extending progression free survival, Abiraterone or Exemestane (Aromasin). The trial is for women with ER+ advanced disease that has already been treated with Letrozole (Femara) or Anastrozole (Arimidex) and both those drug have stopped working.
For more information about the trials contact:
Dr. Tiffany A. Traina at 646-888-5209
Dr. Maura Dickler at 646-888-5456
Christine is the Breast Cancer Program Director at SHARE.