New drug therapies for metastatic, or advanced, breast cancer (MBC) are offering renewed hope for patients, having a significant impact on both lifespan and quality of life. Physicians at Miami Cancer Institute involved in the investigation of several of these new targeted and tailored treatment options are already seeing improvements in outcomes and are optimistic that these advances will not only slow progression, but in some cases decrease the risk of recurrence and progression.

Just a year ago, the U.S. Food and Drug Administration (FDA) cleared the way for the first U.S.-approved I.V. infusion to treat a newly defined category of metastatic breast cancer called HER2-low. The treatment uses an antibody drug conjugate (ADC), trastuzumab deruxtecan (brand name Enhertu).

ADCs are like smart missiles, combining monoclonal antibodies with potent chemotherapy. By latching onto cancer cells with specific cancer markers (antigens), they provide targeted delivery of chemotherapy to cancer cells. Trastuzumab deruxtecan, like some other ADCs, also has what’s known as a “bystander effect,” where the chemotherapy can spread to other nearby cells that express lower levels of HER2 ? the HER2-low cells. Because about half of all metastatic breast cancers are classified as HER2-low, there is a large patient population that could benefit from this new treatment.

Trastuzumab deruxtecan is given intravenously every three weeks. While it is generally well tolerated, physicians must closely monitor patients for the rare yet serious side effect, interstitial lung disease/pneumonitis. To date, many patients have received the drug and their breast cancer is being controlled for a longer period and they are experiencing an overall good quality of life.

Because of their precision in attacking cancer cells, other ADCs are also proving to be much more effective than previously used chemotherapies. Another such therapy, called sacituzumab govitecan (trade name Trodelvy) has also been approved for both triple negative breast cancer (TNBC) and hormone receptor-positive, HER2-negative breast cancer. This therapy also represents an important new treatment option for a significant number of metastatic breast cancer patients.

Physician-investigators at the Institute are conducting cutting-edge clinical research with additional novel ADCs, recently opening a first-line, metastatic triple-negative breast cancer trial with an ADC called datopotumab deruxtecan. They are also studying why some tumors become resistant to ADCs in another trial in collaboration with other institutions.

Physicians at Miami Cancer Institute are also participating in trials investigating a particularly aggressive subtype of breast cancer, TNBC. This subtype accounts for 10 to 15 percent of all breast cancers and is defined by a lack of estrogen and progesterone receptors necessary for targeted therapies. They also don’t overexpress the HER2 protein. This makes treatment options more limited for this type of breast cancer that typically grows and spreads faster.

Patients diagnosed with TNBC at an early stage often still require intensive treatments prior to surgery, including chemotherapy and immunotherapy. Studies which aim to decrease the risk of recurrence for these patients are available at the Institute, including a vaccine study, as well as another trial, which evaluates the genomic make-up of the individual’s cancer to pave the way for developing a personalized and precise treatment strategy. These trials have the potential to change how breast cancer is treated going forward.

As research evolves and novel treatments become available, we will find more avenues to lower the likelihood that cancer will return, slow its spread and continue to see death rates from metastatic breast cancer fall.

For more information on breast cancer care at Miami Cancer Institute, click here. For information on clinical trials, click here.