Trastuzumab emtansine (Kadcyla) and trastuzumab (e.g. Herceptin) are NOT the same and are NOT interchangeable.

Kadcyla is a combination of a monoclonal antibody (trastuzumab) and a cytotoxic agent (emtansine), known as a cytotoxic drug conjugate.

IMSN Safety Alert Confusion Risk with trastuzumab EMTANSINE (Kadcyla) and trastuzumab 

This alert was revised in July 2016.