An international clinical trial has been a promising advance against a variant of breast cancer, the metastatic HER2-positive one. The study, led by the director of the International Breast Cancer Center (IBCC), Javier Cortés, demonstrated the effects generated by the drug trastuzumab deruxtecan (t-DXD) to combat this disease.
The paper has just been published in the New England Journal of Medicine. The Destiny Breast-03 clinical trial tested the safety and efficacy of the drug trastuzumab deruxtecan in patients with metastasized HER2-positive breast cancer, a particularly aggressive subtype of these tumors that affects 20% of patients.
This new treatment slowed the progression of cancer in 75.8 percent of patients at 12 months compared to 34.1 percent who achieve it with the current standard treatment. The study decided to compare the drug previously used with trastuzumab emtansine in patients with HER2-positive metastatic breast cancer.
Among the 524 randomly assigned patients, a study was conducted to analyze overall survival at 12 months. The results showed that the use of trastuzumab emtansine stood at 85.9%, while the new treatment reached 94.1%. The most relevant data of all these percentages is that of the patients who participated in the study, 42 (16.1%) experienced a complete response with trastuzumab deruxtecan and 23 of them, representing 8.7% of the total, did the same with standard treatment.
Javier Cortés, director of the International Breast Cancer Center (IBCC) in Barcelona and the first author of the study, stressed at a press conference when presenting the results that “in 16% of patients treated with the new drug the disease disappears. This also happens in highly medicated patients, and who, therefore, may develop more resistance to new drugs.”
The new drug reduces the risk of illness or death, this is one of the most notable conclusions. The scientists also indicated another value of this research is that among patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane, the risk of disease progression or death was lower among those who received trastuzumab deruxtecan than among those who received trastuzumab emtansine. Treatment with trastuzumab deruxtecan was associated with interstitial lung disease and pneumonitis.
On the other hand, the research related to this drug in patients with HER2-postivian breast cancer does not end here, since throughout this year new data will be known related to toxicity, efficacy and quality of life against active brain metastases that specialists are tracing in subsequent studies that are already being tracked have started. According to the World Health Organization (WHO), breast cancer arises in the lining cells (epithelium) of ducts (85%) or lobules (15%) in the glandular tissue of the breast. Initially, the cancerous growth is limited to the duct or lobe (“in situ”) where it usually causes no symptoms and has minimal potential for spread (metastasis).
In 2020, there were 2.3 million women diagnosed with breast cancer and 685,000 deaths worldwide. By the end of 2020, there were 7.8 million women alive who had been diagnosed with breast cancer in the last 5 years, making it the most prevalent cancer in the world. Women lose more years of life due to disability (DALYs) to breast cancer worldwide than to any other type of cancer. It occurs in every country in the world in women of any age after puberty, but with increasing rates later in life.
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