New “Smart Drug” Has Promising Results
A new triple-negative breast cancer treatment has been tested by researchers at New York Presbyterian/Columbia University’s Herbert Irving Comprehensive Cancer Center and has delivered promising early results.1Triple-negative breast cancer is aggressive cancer with cells that lack three specific receptors on their surface. These receptors are the progesterone receptor, estrogen receptor, and the human epidermal growth factor receptor 2 (HER2). The lack of these receptors means that targeted hormone therapies will not be as effective in this type of cancer as they might be in others. Chemotherapy is currently the main treatment option for women with triple-negative breast cancer. Chemotherapy can cause a variety of side effects because it impacts many other cells and processes in the body besides cancer, which is why new, targeted treatment options are needed for women with triple-negative breast cancers.
How does it work?
Unlike traditional chemotherapy, the “smart drug” being tested, sacituzumab govitecan-hziy, is designed to seek out triple-negative breast cancer cells and deliver high doses of chemotherapy directly to the cells its meant for. The medication does this by combining a directed antibody to a chemotherapy drug. The antibody component acts as a radar and looks for cells that express a protein called trop2 (a protein made by breast cancer cells). When the antibody detects these proteins, it will direct the chemotherapy portion of the drug (irinotecan, SN-38) directly to that location. This allows for high doses of chemotherapy to be directed at the cells that need it, rather than to other areas of the body.
By combining the targeted antibody with the chemotherapy, higher doses of chemotherapy might be feasible since only the cells that the drug is meant for will get the medication. This high level of chemotherapy that may not have been attainable previously may lead to better control of an individual’s triple-negative breast cancer and lead to an overall decrease in tumor size. Tumor shrinkage may help improve quality of life-impacting symptoms, such as decreasing pain.
The recent study on sacituzumab govitecan-hziy was published in the New England Journal of Medicine and followed the outcomes of 108 individuals with triple-negative breast cancer who had been treated by at least two other anticancer treatment options.1 Typically, women with triple-negative breast cancer who have been treated with multiple other treatment modalities have a decreased chance of responding to further therapies, however, this was not the case for sacituzumab govitecan-hziy.
In total, a third of participants responded to the medication and the median overall survival was 13 months. The average length of time that individuals responded to sacituzumab govitecan-hziy was 7.7 months, and responses included tumor shrinkage and an increased length of time between treatment and time it took for the cancer to progress further. The average time to progression was 5.5 months, and nine individuals out of the 108 did not have any cancer progression for over a year after taking the medication. The most common side effects of the medication were diarrhea, fatigue, and hair loss, however, only 3% of individuals who started the trial needed to stop due to side effects.1 The medication did not cause neuropathy (numbness and tingling that can cause pain, especially in the limbs) which is a common and quality of life-impacting side effect of chemotherapy-based treatment options.
A Phase I/II trial centered on sacituzumab govitecan-hziy in direct relation to other treatment options is currently underway to learn more about its safety and efficacy. Sacituzumab govitecan-hziy is also being tested for use in other cancers such as bladder cancer, prostate cancer, and different forms of breast cancer.
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