Aggressive forms of breast cancer also require aggressive treatment that can be highly toxic. The FDA announced Feb. 22 that they have approved a new treatment that clinical trials show is effective and has lower toxicity that can cause decreased quality of life and complications for women with human epidermal growth factor receptor 2 (HER2) positive forms of the disease. The drug is Kadcyla (trastuzumab emtansine); also known as TDM-1.
The chemotherapy drug is novel in that it contains the original drug Herceptin used to treat aggressive estrogen positive breast cancer with another drug attached.
Rush University researchers who participated in clinical trials say the combination treatment for aggressive HER2-positive breast cancer was more effective than standard chemotherapy in studies. HER2 is a protein that can be found in cancer cells in high amounts that causes the disease to keep progressing.
Treated breast cancer that recurs or becomes more aggressive can change from HER2 negative to positive, making the new drug a welcome addition for women battling the disease.
Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research said Kadcyla Is the fourth approved drug that targets the HER2 protein.
The drug specifically targets cancer cells, sparing healthy cells, which is an ongoing goal of researchers for developing cancer treatments.
Dr. Melody Cobleigh, Director of the Comprehensive Breast Center at Rush and lead investigator of the TDM-1 clinical trials at Rush said in a press release, "The tumor cell basically eats the TDM-1 and then, the TDM-1 gets released and destroys the tumor cell from the inside out.”
She adds the therapy is better for breast cancer patients because it’s tolerable and doesn’t have the same debilitating effects as other cancer drugs. In studies, patients did not lose their hair and the drug had fewer overall side effects.
The drug will come with a boxed warning that it can cause liver and heart toxicity and death. In trials, the most common side effects were elevated liver enzymes, fatigue, joint and muscle pain, headache, constipation and abnormal blood counts related to risk of bleeding.
The Phase III trial of the drug, “Super-Herceptin”, included 1,000 patients with breast cancer who either received TDM-1 or standard chemotherapy. The TDM-1 group remained cancer free 9.6 months compared to 6.4 months for the standard treatment group. Breast cancer patients treated with the drug survived approximately 5 months longer.