The complexity of sunitinib dosing in renal cell cancer patients

Sunitinib is an oral multityrosine kinase inhibitor, targeting - among others - vascular endothelial growth factor receptor (VEGFR) and platelet derived growth factor receptor (PDGFR). Sunitinib is one of the first so called targeted therapies which is approved as first line treatment for metastatic renal cell carcinoma (mRCC), and for second line in Gastro intestinal stromal tumors (GIST) and Pancreatic neuroendocrine tumors (PNET). Its introduction in 2006 introduced a new era in the treatment of mRCC, but also raised a lot of clinical relevant questions. One of these is which dosing schedule is most efficient with the lowest toxicicity and the best quality of life. The approved schedule for sunitinib is 50 mig oid in the so called “4 weeks on and two weeks off” (4/2 schedule).