Onyx Pharmaceuticals, Inc. was a biopharmaceutical company headquartered in South San Francisco, California. Founded in 1992, it focused on developing and commercializing innovative therapies targeting the molecular mechanisms of cancer, particularly through kinase inhibition and proteasome inhibition platforms.
The company co-developed Nexavar (sorafenib) with Bayer HealthCare Pharmaceuticals, approved for unresectable hepatocellular carcinoma and advanced renal cell carcinoma. It also advanced Kyprolis (carfilzomib) for multiple myeloma following the 2009 acquisition of Proteolix, and partnered on assets like Stivarga (regorafenib).
Onyx went public on NASDAQ (ONXX) in 1996 and employed about 741 people by 2012. In 2013, it was acquired by Amgen for $10.4 billion and ceased independent operations.
