Kadcyla (generic: ado-trastuzumab emtansine) is a prescription medication used to treat people with HER2 positive breast cancer that has spread to other parts of the body who have already been treated with trastuzumab (Herceptin) and a taxane. Kadcyla belongs to a group of drugs called antibody-drug conjugates (ADCs). It works by attaching to cancer cells and delivering chemotherapy directly to them, disrupting certain functions in the cells necessary for cell division.

This medicine comes in an injectable form to be given directly into a vein (IV) by a healthcare provider, once every 3 weeks. 

Common side effects of Kadcyla include tiredness, nausea, and pain affecting the bones, muscles, ligaments and tendons.