How a Targeted Approach Has Changed the Way We Treat Certain Patients with HER2 Positive Metastatic Breast Cancer

Learn more about a HER2 directed antibody drug conjugate. Sponsored Content by Daiichi Sankyo and AstraZeneca.

In 2021, nearly 285,000 people will be diagnosed with breast cancer in the U.S.1 The average risk of a woman in the U.S. developing breast cancer sometime in her life is about 13%. That means that one in eight women will be diagnosed with breast cancer, and of those, one in three will become metastatic.2,3 Historically, the prognosis for people living with metastatic breast cancer has been poor, with approximately 28% of patients living approximately five years after diagnosis.4 In this late stage of the disease, treatment options become increasingly limited as the tumor has spread beyond the breast to other parts of the body. Thanks to ongoing scientific research, the development of treatments targeting certain biomarkers, which are known to have a role in the development of cancer, has significantly changed the way certain patients with metastatic breast cancer may be treated.

Biomarkers may indicate an underlying condition or disease and include proteins, genes or other molecules that impact how cells grow and multiply. In cancer, they may also help identify which therapies a particular patient’s tumor may or may not respond to. An important biomarker in patients with metastatic breast cancer is commonly known as HER2 (human epidermal growth factor receptor 2). Approximately one in five people diagnosed with breast cancer are considered HER2 positive, which means that cancer cells may grow and spread faster than other types of breast cancer.5

While chemotherapy and radiation continue to be used in the treatment of some patients with HER2 positive metastatic breast cancer, in recent years, advances in antibody drug conjugates (ADCs) have brought renewed hope to the treatment of the disease.

“Testing for biomarkers, such as HER2, enables physicians and patients to better understand the unique qualities of their cancer to help inform treatment options, such as antibody drug conjugates,” said Mohammad Jahanzeb M.D., FACP, FASCO, founder and managing partner at Florida Precision Oncology Research and Consulting, LLC. “This therapeutic approach is designed to use HER2 as a target to deliver the cancer-killing medicine to the cancer cell.”

One such ADC is ENHERTU® (fam-trastuzumab deruxtecan-nxki), which was approved by the FDA in 2019 for the treatment of adults with HER2 positive breast cancer that cannot be removed by surgery or that has spread to other parts of the body, and who have received two or more prior anti-HER2 breast cancer treatments. ENHERTU was FDA approved for this use based on a clinical study that measured how many patients responded and how long they responded. ENHERTU is still being studied to confirm these results. It is not known if ENHERTU is safe and effective in children.

“Despite initial treatment with currently available standards of care, many patients with HER2 positive metastatic breast cancer will often experience disease progression,” said Dr. Jahanzeb. “ENHERTU may be an option for patients with this form of metastatic breast cancer who have failed two or more prior therapies. During the European Society for Medical Oncology 2021 Congress, the DESTINY-Breast03 phase 3 trial was presented, which evaluated the investigational use of ENHERTU in patients with HER2 positive metastatic breast cancer in the second-line setting, which is not FDA approved.”

ENHERTU can cause serious side effects including lung problems that may be severe, life threatening, or that may lead to death; low white blood cell count; heart problems that may affect your heart's ability to pump blood; or harm to an unborn baby. See Important Safety Information below.

“The development of targeted therapies has helped reshape the way we treat many patients diagnosed with HER2 positive metastatic breast cancer. There are additional studies on the horizon for ENHERTU and other HER2 directed medicines,” said Jahanzeb. “While there is still a lot more work to be done, if we continue at the current rate of scientific advancement, I am optimistic about the future of metastatic breast cancer treatment.”

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1 Cancer.Net. Breast Cancer - Metastatic: Statistics. January 2021.

2 American Cancer Society. How Common Is Breast Cancer? May 2021.

3 METAvivor. Metastatic Breast Cancer Statistics. Accessed August 2021.

4 American Cancer Society. Survival Rates for Breast Cancer. January 2021.

5 Cancer.Net. ASCO: Breast Cancer. Accessed August 2021.