Plexxikon

Plexxikon was an American drug discovery company based in South San Francisco, California, that developed novel small molecule pharmaceuticals using its proprietary Scaffold-Based Drug Discovery platform. Co-founded in 2001 by Yale University pharmacology professor Joseph Schlessinger and UC Berkeley professor Sung-Hou Kim, the company successfully advanced two drugs through FDA approval — vemurafenib (Zelboraf) for melanoma and pexidartinib (Turalio) for tenosynovial giant cell tumor. Plexxikon was acquired by Daiichi Sankyo in April 2011 for $805 million and was permanently shut down in March 2022.