A New Drug For Triple Negative Breast Cancer Seems Promising — Enzalutamide

Breast cancer. The two words strike fear in nearly everyone’s heart, as, by far, it is the most common cancer that women can get. In fact, one-out-of-eight women will be diagnosed at some point in their lives. Early detection remains the most important tool we have against fighting breast cancer, but it’s only one tool. Not at all tests reliably show all breast cancers in their early stages, and many breast cancers are not detected until they begin to metastasize, or spread to remote locations in the body, which makes them incurable. They can be treated, but it is medically deemed impossible to cure at that point in time, with various metastatic lesions having to be handled as they appear — which means more chemo, more radiation, more lost quality of life.

What many people don’t realize is that there are actually several kinds of breast cancer — not all are the same or are treated the same. Many breast cancers have hormone receptors which are considered easier to treat the other types, because when biological therapy denies the tumor of the particular hormone that feeds it, the tumor dies.

Triple-negative breast cancer, however, does not respond to hormone or biological therapies — that’s because the tumor does not have those receptors. It also is a particularly aggressive cancer that usually strikes women in their childbearing years and moves quickly to the brain and bones. Lumpectomies, Mastectomies, chemotherapy, and radiation have been the medical standard, but often with dismal results — the five year prognosis for triple-negative breast cancer is not good.

However, a new drug on the market seems promising in the fight against this disease that takes far too many young women. A drug used to treat prostate cancer in men seems promising — called Enzalutamide — shows promise in a subset of women with advanced triple-negative breast cancer. For women whose tumors express the androgen receptor (approximately 40 percent) the drug shrank or stopped tumor activity.

Tiffany Traina, a medical oncologist at Memorial Sloan Kettering Cancer Center in New York, who specializes in breast cancer, spoke about the trial which included 118 women, 47 percent of which had triple-negative breast cancer with androgen receptors.

“Enzalutamide is an oral therapy and extremely well tolerated. We are seeing impressive improvements in progression-free survival [PFS] and in the clinical benefit rate. AR by immunohistochemistry is not perfect in predicting who is going to respond. This is not the whole story. We found that even those with really low AR expression level have had great responses [on trial. Combining AR expression with the gene signature has allowed us to enrich for the population that appears to truly benefit from enzalutamide. This is the most exciting data we have had in triple-negative breast cancer and certainly supports moving this therapy forward in development.”

[Image courtesy of Pfizer]