Breast Cancer: Exciting Advancements in Immuno and Targeted Therapies

Every day, physician-researchers in Miami and around the world are increasing our understanding of breast cancer – what causes it, how it can be treated and what can be done to prevent it. They’re driving remarkable advances in breast cancer treatment and giving patients diagnosed with the disease more reason for hope.

Naomi Dempsey, M.D., and Ana Cristina Sandoval Leon, M.D., breast medical oncologists at Baptist Health Miami Cancer Institute, spoke recently about how breast cancer care is rapidly evolving from a “one size fits all” approach to one that uses targeted therapies to target the precise genetic makeup of a tumor’s cells and jumpstart the patient’s immune system to kill those cells.

Destroying cancer cells from the inside

Targeted drug therapy uses medicines that target proteins on breast cancer cells that help them grow, spread, and live longer. They work to destroy cancer cells or slow down their growth and have side effects different from chemotherapy.

Like chemotherapy, these drugs enter the bloodstream and reach almost all areas of the body, which makes them useful against cancers that have spread to distant parts of the body. Targeted drugs sometimes work even when chemo drugs do not and can help increase the efficacy of other types of treatment.

Some targeted therapy drugs – monoclonal antibodies, for example – work in more than one way to control cancer cells and may also be considered immunotherapy because they help boost the immune system.

Naomi Dempsey, M.D., breast medical oncologist with Baptist Health Miami Cancer Institute

Immunotherapy is an exciting new class of medication now being used to treat breast cancer and a number of other different tumor types, according to Dr. Dempsey, who sees patients at Miami Cancer Institute in Plantation. Immunotherapy currently is only approved in patients with early-stage breast cancer and also for those with metastatic, triple negative breast cancer, she says.

“We develop cancer cells on a fairly regular basis but our immune system recognizes those cancer cells as foreign and kills them. Sometimes, however, the immune system isn’t doing its job quite right for whatever reason and a cancer cell gets by and forms a tumor. With immunotherapy, we can activate the patient’s immune system to kill their cancer cells,” Dr. Dempsey explains.

The main concern with immunotherapy is that it can activate the immune system too much, says Dr. Sandoval Leon. As a result, “patients can have different sorts of immune-related adverse events that can affect any organ or system. So you can have skin rash, hypothyroidism,  inflammation of the heart, inflammation of the lungs, and inflammation of the colon, among other side effects,” she says.

Harnessing the combined power of different drugs

Depending on the patient and their cancer type and stage, immunotherapy is often used in conjunction with chemotherapy. According to Dr. Sandoval Leon, who sees patients at Miami Cancer Institute in Miami, several other types of targeted therapy drugs can be used to treat breast cancer.

Ana Cristina Sandoval Leon, M.D., breast medical oncologist with Baptist Health Miami Cancer Institute

“We have monoclonal antibodies such as trastusumab and pentuzumab that are being used to treat HER 2 positive breast cancer and have significantly improved the prognosis of this type of breast cancer,”,” Dr. Sandoval Leon explains.

“We also have a rapidly emerging class of therapeutic agents known as antibody-drug conjugates, or ADCs, that combine the precision of a monoclonal antibody with a cytotoxin or type of chemotherapy. These have proven to be highly successful in treating different types of breast cancer.”

There are more than a 100 new ADCs in clinical trials encompassing a wide variety of tumor types, according to Dr. Sandoval Leon. Trastusomatheroxican is used for patients with HER 2 positive or HER 2 Low breast cancer, she says, while tristusomathyroxy is helping to improve outcomes in patients with metastatic HER 2 Low breast cancer. “We also have another ADC, sasitusumab, that we can use to treat hormone positive and triple negative breast cancer,” she adds.

Advancing science and improving outcomes

Clinical research is helping advance science and improve outcomes in patients with breast cancer, and both Dr. Dempsey and Dr. Sandoval Leon emphasize the value of these studies.

“Patients at Miami Cancer Institute have the opportunity of participating in a number of different clinical trials, and that’s extremely important because that is how we move the field forward,” says Dr. Sandoval Leon.

Dr. Dempsey echoes her colleague’s sentiments. “I encourage patients to keep an open mind regarding any clinical trials that they would be a good candidate for. There are a lot of benefits to being open to clinical trials. They give women access to potentially better therapies that are not yet widely available anywhere else,” she points out. “Plus, they’re not only helping themselves but also other cancer patients in the future.”

Dr. Dempsey says breast cancer treatment is entering an “exciting new era” of personalized medicine in which every patient gets the exact amount of treatment required in order to maximize efficacy and minimize toxicity.

“We don’t want to over-treat anybody and we don’t want to under-treat anybody, so we're really trying to understand your specific cancer,” Dr. Dempsey says. “What is its extent? Has it spread? If so, where, and what is feeding it? Then we can cut off those food sources, and that's where targeted therapy can be really useful.”