Onyx's lead product, Nexavar® (sorafenib) tablets, is an oral, small molecule agent currently approved in the U.S.(view press release) and the EU (view press release) for the treatment of patients with advanced kidney cancer, as well as in the U.S. (view press release) and the EU (view press release) for the treatment of liver cancer.

As part of a broad development program, Nexavar is also currently being evaluated in randomized trials in non-small cell lung cancer, breast cancer, melanoma and other tumor types. The agent is also being studied in multiple Phase 2 trials in lung, breast and other cancers, as well as in several Phase 1b trials of the agent administered in conjunction with standard chemotherapy drugs and other anticancer agents. Nexavar was discovered and is being codeveloped by Onyx and Bayer HealthCare Pharmaceuticals.

Nexavar is a novel multiple kinase inhibitor that targets proteins involved in both tumor cell proliferation and angiogenesis (the formation of new blood vessels to support cancer cell growth). In preclinical studies, Nexavar was shown to inhibit the enzyme RAF kinase, which is a critical component of the RAS pathway - an important cascade of chemical signals that controls cell division. Abnormal activation of the RAS pathway is believed to play an integral role in the genesis of many cancers. Additionally, Nexavar inhibits VEGFR-2 and PDGFR-ß, key receptors of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), which play important roles in angiogenesis. Nexavar also inhibits other tyrosine kinases such as c-KIT and FLT-3.

Our next product candidate is a small molecule inhibitor of a cyclin-dependent kinase. A product of our cell cycle collaboration with Warner-Lambert Company, now a subsidiary of Pfizer, Inc, this novel cell cycle inhibitor entered clinical testing in 2004.