Sorafenib Tosylate, also known as Bay 43-9006, is a novel bi-aryl urea compound that inhibits cell proliferation by targeting receptor tyrosine kinases, including VEGFR-2 and PDGFR-β and their associated signaling cascades of the ERK pathway and angiogenesis. It was originally developed as a Raf kinase inhibitor. It has been shown to have activity against several receptor tyrosine kinases involved in tumorigenesis and angiogenesis. Sorafenib is not active against erbB1, erbB2, ERK-1, MEK-1, EGFR, HER-2, IGFR-1, c-MET, c-yes, PKB, PKA, cdk1/cyclinB, PKC, or pim-1. Sorafenib has been shown to inhibit various nonkinase targets, including adenosine A3, dopamine D1, and muscarine M3 receptors, but at much higher (micromolar) concentrations than kinase targets. It is also the active ingredient in a drug that has been approved in at least one country for use in patients with advanced renal cell cancer. This version is NOT for human use.