New treatments offer hope for breast cancer patients

Recent advances in targeted therapies have changed the landscape for breast cancer patients, according to Medical Oncologist Jaclyn C. Flanigan, MD.

“All of this is translating to greater quality of life,” she said. “I think we have some really meaningful outcomes and patients are living longer.”

Dr. Flanigan, who practices at the Davenport-Mugar Cancer Center at Cape Cod Hospital in Hyannis, said new therapies are generally less harsh than traditional chemotherapy, which uses toxic drugs to kill quick-growing cells in tumors. Unfortunately, these drugs also kill healthy fast-growing cells throughout the body.

Chemotherapy drugs can kill cells in your digestive tract, bone marrow cells that make blood cells, and those in your hair follicles, according to the American Cancer Society. Some of these drugs can harm your nervous system and organs including your heart, lungs and kidneys.

So-called ‘targeted therapies’ focus more on cancer cells. According to the American Cancer Society, these treatments include:

• Monoclonal antibodies. Laboratory-created antibodies, each one of which is designed to bind to a specific protein found in tumor cells, and thereby interfere with tumor growth.
• Antibody-drug conjugates. These treatments use antibodies to carry chemotherapy drugs directly to tumors by seeking out and attaching to specific proteins in cancer cells.
• Kinase inhibitors and other types of inhibitors. These block specific proteins in tumor cells needed for growth and cell operation.

“We’ve definitely seen many changes in breast cancer treatment in the past five years … many more targeted therapies,” Dr. Flanigan said.

Side effects from targeted therapies vary with the drug used, and not everyone experiences them, according to the American Cancer Society. Side effects may include skin problems and rashes, autoimmune reactions, allergic reactions, heart and circulatory problems, breathing problems, nausea, fatigue, hair loss, and increased risk of infection.

While targeted therapies can cause significant side effects, they are “generally less toxic” than traditional chemotherapy, which can cause “a lot more side effects,” Dr. Flanigan said. She also noted some of these new treatments may be easier for patients to accommodate, as some can be taken as pills or injection rather than via intravenous infusion sessions at the hospital.

New Treatment Approved in August

A new antibody-drug conjugate approved this summer offers hope to women previously screened out from receiving targeted treatment aimed at a protein called HER2 (human epidermal growth factor receptor 2). Breast cancer patients with elevated HER2 levels tend to have tumors that grow faster and more aggressively, the American Cancer Society says.

Laboratory testing divides patients as either HER2-positive or HER2-negative. This meant some patients with low levels of HER2 were considered HER2-negative, and ineligible for treatment with existing HER2 targeted therapies, said Dr. Flanigan. However, in August, the U.S. Food and Drug Administration approved the first targeted treatment of HER2-low breast cancer. The treatment, fam-trastuzumab-deruxtecan-nxki (Enhertu), is approved for patients with cancer that can’t be surgically removed or has spread in their bodies. The FDA estimates 80-85 percent of new breast cancer cases are HER2-negative and 60 percent of those are actually HER2-low.

Many of these targeted therapies are for use in patients with advanced stages of cancer, after other treatment has been tried, Dr. Flanigan said. Some have been approved for less progressed disease. For example, abemaciclib (Verzenio), a cyclin-dependent kinase inhibitor, can be used in early stage cancer that is HER2-negative, hormone receptor positive, and has metastasized to lymph nodes and is considered a high risk of recurring after surgery, according to the American Cancer Society.

“In general, most of these are being developed in advanced setting,” Dr. Flanigan said, adding that’s partially the result of how clinical trials to test new drugs are done.

Clinical Trials Coming to Cape Cod

Clinical trials are the final steps toward FDA approval after researchers create a drug. Following years of laboratory testing, trials check a treatment’s safety, effects, proper dosage and effectiveness in patients, according to the National Cancer Institute. Two clinical trials of breast cancer treatments will be held at Cape Cod Hospital, Dr. Flanigan said, crediting her fellow oncologists, Edward J. Wyluda, DO, and Thomas Openshaw, MD, MS, for bringing them to the hospital.

One trial will look at the effect of tucatinib (Tukysa), a kinase inhibitor, on residual disease in women with estrogen receptor negative, HER2-positive breast cancer, when given along with T-DM1 (a conjugate of a monoclonal antibody that locks onto HER2, and DM1, an anti-cancer drug), according to a description of the trials that Dr. Flanigan provided. Some participants will get a placebo instead of tucatinib.

The second trial will study camizestrant (AZD9833), a selective estrogen receptor degrader, in women with estrogen receptor-positive, HER2-negative breast cancer in early stages who have moderate to high risk of recurrence and have undergone two years of endocrine therapy without recurrence. According to a 2021 article in the Journal of Clinical Oncology, more than 66 percent of advanced breast cancer cases are estrogen receptor positive and HER2-negative, and endocrine therapy ultimately becomes ineffective in most advanced cases. The trial will compare results to those of patients who receive standard care.

According to an August 2020 article in Seminars in Oncology, standard care for early-stage hormone receptor positive breast cancer consists of endocrine therapy to which chemotherapy and/or ovarian function suppression therapy may be added, a situation the authors said was likely to change with the emergence of new drugs.

Dr. Flanigan said she hopes the two trials will begin accepting participants within the next few months.

Patients do not need to travel to Boston for new cancer treatments, Dr. Flanigan said, citing the coming clinical trials and Cape Cod Hospital’s collaboration with Dana-Farber Cancer Institute. The number of new treatments now available, with more in development, provides hope to her patients, she said.

“It’s not just one (new) drug. Fortunately, there are so many drugs,” she added. “We use these every day in practice.”