Cyclin-dependent kinase 8 (CDK8) is an oncogenic protein that regulates RNA synthesis (transcription). CDK8 is required for transcriptional activation of previously silent genes, many of which play a role in carcinogenesis, metastasis and the development of drug resistance in cancers. In contrast to some other proteins of the same CDK family, CDK8 is not required for cell growth, and CDK8 inhibition has no major effects under normal conditions. Senex has developed and chemically optimized the first selective small-molecule inhibitors of CDK8 and its “twin” CDK19 and discovered novel uses for CDK8/19 inhibitors in the treatment of cancer, viral diseases, inflammatory and cardiovascular diseases. Senex’s lead CDK8/19 inhibitor is currently undergoing preclinical development in preparation to clinical trials in prostate and breast cancers.