MONDAY, September 20, 2021 (HealthDay News) – New research offers good news for women with aggressive HER2-positive breast cancer.
A targeted therapy, trastuzumab deruxtecan (T-DXd), sold as Enhertu, triples the length of time the cancer stays under control compared to the current gold standard, trastuzumab emtansine (T-DM1).
These two drugs are second-line treatment options for HER2-positive breast cancer that has continued to spread after the initial treatment.
“It really blew T-DM1 in terms of progression-free survival,” said study co-author Dr Sara Hurvitz, director of clinical breast cancer research at the Jonsson Comprehensive Cancer Center in UCLA.
Up to 20% of breast cancers are HER2-positive, which means there is too much of a protein called human epidermal growth factor receptor 2 on the surface of the cell, causing the cancer to work more aggressively, explained Hurvitz.
Currently, the first-line treatment for women with this type of breast cancer is treatment with HER2 antibodies with pertuzumab / trastuzumab plus chemotherapy. If the cancer progresses, the standard treatment is to switch to T-DM1 (sold as Kadcyla), which includes trastuzumab and chemotherapy.
But the new study could change that paradigm, Hurvitz said.
Administered intravenously, T-DXd binds to the HER2 protein, blocking its growth, and delivers high concentrations of chemotherapy directly to cancer cells which overexpress HER2.
The new study was funded by T-DXd makers Daiichi Sankyo Inc. and AstraZeneca.
In the study of 524 women with HER2-positive breast cancer, those who received T-DXd had a 72% improvement in their progression-free survival compared to their counterparts who were treated with T -DM1.
At one year, 76% of women taking T-DXd had no signs of disease progression. In contrast, only 34% of women taking T-DM1 have not seen disease progression after one year.
“This drug really lengthens the progression-free survival time or the time before a patient needs to change treatment because the one they are on has stopped working and their disease is getting worse,” said Hurvitz . “This is great news for patients.”
In addition, tumors shrank in almost 80% of women taking T-DXd, compared to only 34% treated with T-DM1. According to the study, 16% of women treated with T-DXd showed no signs of disease at one year. The new drug appeared to work particularly well in women whose breast cancer had spread to the brain, Hurvitz said.
The results were presented this weekend at the annual meeting of the European Society for Medical Oncology. Research presented at meetings is generally considered preliminary until it is published in a peer-reviewed journal.
One of the main safety concerns with this drug is the risk of interstitial lung disease, a group of lung conditions that causes scarring of lung tissue, Hurvitz said. The risk was low in the new study, and women who developed interstitial lung disease tended to have mild cases, she said.
External experts are equally enthusiastic about the study results and what they may mean for women with advanced HER2-positive breast cancer.
“T-DXd represents a new standard of care, used in place of TDM-1, in advanced breast cancers overexpressing HER2,” said Dr. Charles Shapiro. He is Professor of Medicine, Hematology and Medical Oncology at Icahn School of Medicine in Mount Sinai and Breast Medical Oncologist at Mount Sinai Tisch Cancer Center in New York City. “The world is brighter for women with HER2 overexpressing breast cancer.”
“This study could lead to a change in the standard of care for patients with HER2-positive metastatic breast cancer,” said Dr. Jesus Anampa Mesias, medical oncologist at Montefiore Einstein Cancer Center in New York City. “The results of this study are impressive and unprecedented [and] will definitely change the way I care for women with HER2-positive metastatic breast cancer. “
Learn more about HER2-positive breast cancer at the American Cancer Society.
SOURCES: Sara Hurvitz, MD, director, Clinical Breast Cancer Research Program, Jonsson Comprehensive Cancer Center, UCLA; Charles Shapiro, MD, professor of medicine, hematology and medical oncology, Icahn School of Medicine, Mount Sinai, and breast medical oncologist, Mount Sinai Tisch Cancer Center, New York; Jesus Anampa Mesias, MD, medical oncologist, Montefiore Einstein Cancer Center, New York; Congress of the European Society of Medical Oncology, September 16-21, 2021