Tumor-shrinking drug shows major impact on life expectancy for breast cancer patients
An antibody-drug conjugate (ADC) significantly improves the life expectancy of people who have some of the most serious forms of breast cancer, new data released Saturday at the 2021 European Society of Medical Oncology conference showed.
Researchers found that the size of tumors were significantly reduced and life expectancy increased for patients with the incurable HER-2-positive breast cancer who used the novel antibody-drug conjugate ENHERTU.
ADCs are highly targeted biopharmaceutical drugs that are intended to kill tumor cells while sparing healthy cells. They combine monoclonal antibodies specific to surface antigens present on particular tumor cells with highly potent anti-cancer agents linked via a chemical linker.
While ENHERTU has been used as a second-line of treatment, the results presented in the data could push health officials to start recommending it be used as an initial treatment method.
“The outcome of this trial is very clinically meaningful for HER-2-positive breast cancer patients,” Dr. Sara Tolaney, Chief, Division of Breast Oncology, Dana-Farber Cancer Institute, who was part of the research team, told ABC News.
“This potent antibody drug ... will dramatically change the treatment for HER-2 positive breast cancer,” ABC reported.
Global clinical trials
ENHERTU was approved in 2019 by the Food and Drug Administration (FDA) for inoperable or metastatic HER-2-positive breast cancer. The FDA said the treatment could be given to patients who did not respond to the standard treatment and only after at least two combination options were tried.
Globally, breast cancer is the deadliest type of cancer for women. In 2020, 2.3 million women around the world were diagnosed with cancer and 685,000 others died of the disease, according to the World Health Organization (WHO).
About 1 in 5 people with breast cancer test carry the HER-2 gene, which makes this form of the cancer more aggressive than other types.
In 2017, the Food and Drugs Association approved a trial to compare the results of ENHERTU with TDMI – the standard care medication given to cancer patients. The trial by British-Swedish pharmaceutical company AstraZeneca and Japanese pharmaceutical company Daiichi Sankyo was the first global randomized clinical trial for HER-2-positive breast cancer.
Approximately 500 patients above the age of 18 in 15 countries across Asia, Europe, North America, Oceania and South America were included in the trial. Half were treated with ENHERTU, while the other half were given TDM1.
The drug showed to be twice as effective as TDM1 controlling the disease. While both are antibody-drug conjugate medications and are delivered directly through a person’s veins, ENHERTU is engineered differently, according to the researchers.
One year into the trial, researchers found that fewer than 25 percent of patients treated with ENHERTU showed disease progression – meaning the cancer spread to other organs or became more severe, and in many cases to death.
Meanwhile, 65 percent of patients treated with TDM1 experienced disease progression or death.
Dr. Sunil Verma, vice president and global clinical head of breast cancer research at AstraZeneca, told ABC News that tumors shrunk in about 80 percent of patients treated with ENHERTU and 16 percent of the patients’ tumors could no longer be seen using imaging technology because of how small they became.
“With the remarkable results of this study, ENHERTU might become the new standard of care treatment for patients with HER-2-positive metastatic breast cancer following standard chemotherapy,” Verma added.