December 20, 2019
The U.S. FDA has approved Enhertu® (fam-trastuzumab deruxtecan-nxki), manufactured by Daiichi Sankyo, to treat adult patients who have unresectable or metastatic HER2-positive breast cancer and have been treated with at least two prior anti-HER2-based regimens in the metastatic setting.
Breast cancer is the most common form of cancer diagnosed in women in the United States. Approximately one in five breast cancers is HER2-positive, meaning the cancer cells possess a genetic mutation that causes overproduction of human epidermal growth factor receptor 2 (HER2) – a protein that causes these cancers to be more aggressive. Metastatic breast cancer, which is cancer that has spread through the body, has a five-year survival rate of just 22%.
In a clinical trial, Enhertu delivered an overall response rate of 60.3% and a median duration of response of 14.8 months. Women who took part in the trial had been treated with anywhere from two to 17 different therapies before beginning treatment with Enhertu. Recommended dosing is 5.4mg/kg of body weight administered via intravenous infusion once every three weeks until disease progression or unacceptable toxicity. A black box warning cautions that there is a risk of interstitial lung disease, which can be fatal, and embryo-fetal toxicity.
Enhertu is expected to launch in January 2020 at a wholesale acquisition cost of $2,295.97 for a 100mg vial.
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