A new treatment, which combines targeted therapy with chemotherapy, has been shown to be highly effective in breast cancer. It is the drug “trastuzumab deruxtecan”, a kind of immunotherapy that increases disease-free survival and average survival compared to the usual treatments that are applied.
An international phase three study, in which four Catalan centers have participated, tests the efficacy of this drug in a new segment of women: those who have a HER2-negative tumor. It reduces mortality by up to 40% and controls the disease twice as long as chemo. The ‘trastuzumab’ is the most “revolutionary” of recent months in the investigation of this disease and opens the door to treat other types of cancer.
In March, a study led by the International Breast Cancer Center (IBCC) already showed that ‘trastuzumab deruxtecan’ improved progression-free survival at 12 months in patients with HER2-positive metastatic breast cancer, one of the most aggressive . But now researchers have seen how this same drug is also effective in another population: women with HER2-negative metastatic cancer.
Breast cancer is the most frequent tumor in women worldwide: it affects 2.3 million people and causes the death of 571,000 each year. Molecular classification allows deciding which is the best treatment according to the characteristics of the tumor. Among the different subtypes, HER2-negative breast cancers are 70% of tumors.
The new research, which studied 650 women, has been published in the “New England Journal of Medicine”, and four Catalan centers have participated in it: the August Pi i Sunyer Biomedical Research Institute (Idibaps) of the Hospital Clínic, the Vall d ‘Hebron Institute of Oncology (VHIO), the Catalan Institute of Oncology (ICO) and the Bellvitge Biomedical Research Institute (Idibell). The results were presented last week at the American Society of Clinical Oncology (ASCO), which was held in Chicago (USA).
What is HER2?
HER2 is a protein found on the outside of tumor cells and its levels are routinely determined to decide the most appropriate treatment strategy for breast cancer. In the case of HER2-negative metastatic tumors, it has been seen that 55% do not have amplification of the HER2 gene (therefore, until now, they are considered HER2-negative), but 70% of these express low levels of the protein HER2 (they are HER2-low or HER2-low, in English).
The study in the “New England Journal of Medicine” shows that “trastuzumab” has “clearly greater efficacy” than chemotherapy, controls the disease “twice as long” and “reduces the risk of dying by 40%”.
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