HDAC9 and cancer: HDAC inhibitors have made great progress as anti-cancer agents, including the HDAC inhibitor panobinostat, developed by Novartis; Zolinza, an HDAC inhibitor developed by MERCK and on the market since 2006; Istodax, an HDAC inhibitor developed by Celgene and FDA approved in 2010; and other new drugs that are in preliminary trials, most of which are new HDAC inhibitors.