On February 22, 2013, the FDA Approved a new drug, Kadcyla, which is used to treat patients with HER-2 positive metastatic breast cancer. This drug is different than the usual breast cancer drugs because it not only targets cancer cells, it spares healthy ones. Kadcyla combines Herceptin with other chemotherapy drugs and keeps them intact until it reaches the tumor to kill cancer cells. The drug is only approved for patients who had little progress taking Herceptin and/or taxane, which are both used in the treatment of breast cancer. In clinical trials, this drug delayed progression of cancer by several months compared to lapatinib plus capecitabine therapy. The median overall survival was 30.9 months in the Kadcyla group and 25.1 months in the lapatinib plus capecitabine group. The price for Kadcyla is currently $9,800/month compared to the price of Herceptin at $4,500/month.
HER-2 is an oncogene expressed in 20% of breast cancer cases and is usually a more aggressive type of cancer. When the ERBB2 oncogene is amplified, it greatly increases the expression of HER-2 on tumor breast cells which transforms them into a malignant phenotype, accelerating tumorigenesis.
HER-2 source: http://www.molecularonc.com/mor/mor010106.html