Sorafenib, sold under the brand name Nexavar, is a kinase inhibitor drug approved for the treatment of primary kidney cancer (advanced renal cell carcinoma), advanced primary liver cancer (hepatocellular carcinoma), FLT3-ITD positive AML and radioactive iodine resistant advanced thyroid carcinoma. Mechanism of action Sorafenib is a protein kinase inhibitor with activity against many protein kinases, including VEGFR, PDGFR and RAF kinases. Of the RAF kinases, sorafenib is more selective for c-Raf than B-RAF. (See BRAF (gene)#Sorafenib for details the drug's interaction with B-Raf.) Sorafenib treatment induces autophagy, which may suppress tumor growth. Based on its 1,3-disubstituted urea structure, sorafenib is also a potent soluble epoxide hydrolase inhibitor and this activity likely reduces the severity of its adverse effects. Medical uses Sorafenib is indicated as a treatment for advanced renal cell carcinoma (RCC), unresectable hepatocellular carcinomas (HCC) and thyroid cancer. Kidney cancer Clinical trial results, published January 2007, showed that, compared with placebo, treatment with sorafenib prolongs progression-free survival in patients with advanced clear cell renal cell carcinoma in whom previous therapy has failed. The median progression-free survival was 5.5 months in the sorafenib group and 2.8 months in the placebo group (hazard ratio for disease progression in the sorafenib group, 0.44; 95% confidence interval [CI], 0.35 to 0.55; P<0.01). In Australia this is one of two TGA-labelled indications for sorafenib, although it is not listed on the Pharmaceutical Benefits Scheme for this indication. Liver cancer At ASCO 2007, results from the SHARP trial were presented, which showed efficacy of sorafenib in hepatocellular carcinoma. The primary endpoint was median overall survival, which showed a 44% improvement in patients who received sorafenib compared to placebo (hazard ratio 0.69; 95% CI, 0.55 to 0.87; p=0.0001). Both median survival and time to progression showed 3-month improvements; however, there was no significant difference in median time to symptomatic progression (p=0.77). There was no difference in quality of life measures, possibly attributable to toxicity of sorafenib or symptoms related to underlying progression of liver disease. Of note, this trial only included patients with Child-Pugh Class A (i.e. mildest) cirrhosis. Because of this trial sorafenib obtained FDA approval for the treatment of advanced hepatocellular carcinoma in November 2007. In a randomized, double-blind, phase II trial combining sorafenib with doxorubicin, the median time to progression was not significantly delayed compared with doxorubicin alone in patients with advanced hepatocellular carcinoma. Median durations of overall survival and progression-free survival were