This evidence was rapidly followed by a directive of the European Medicines Agency (EMA) that restricted the use of panitumumab (Vectibix®) and cetuximab (Erbitux®) to patients with KRAS and NRAS (exon 2, 3 and 4) wild type metastatic colorectal cancer [17]. This evidence concerns the gene KRAS and metastatic colorectal cancer.