Trastuzumab is a monoclonal antibody used to treat breast cancer.
It targets HER2, inducing an immune-mediated response that causes internalization and downregulation of HER2, and may also upregulate cell cycle inhibitors such as p21Waf1 and p27Kip1.
It is administered through intravenous infusion every week.
In 2016, it sold €1.2 billion in Europe.
It has an immunogenicity rate of 3-6%.
Labs that test for drug level: