Monoclonal antibodies have played a major role in the treatment of cancer, with approved, active drugs such as Herceptin, Erbitux, Avastin and Rituxan for a wide range of therapeutic applications. Our focus has been on developing next-generation cancer therapeutics by using monoclonal antibodies for the selective delivery of high potency chemotherapeutic drugs. This presentation will give a background on targeted drug delivery, an overview of how Adcetris was discovered and developed, and some reflections on where this area of science is headed.