An epoxomicin derivate with potential antineoplastic activity. Carfilzomib irreversibly binds to and inhibits the chymotrypsin-like activity of the 20S proteasome, an enzyme responsible for degrading a large variety of cellular proteins. Inhibition of proteasome-mediated proteolysis results in an accumulation of polyubiquinated proteins, which may lead to cell cycle arrest, induction of apoptosis, and inhibition of tumor growth. Check for active clinical trials using this agent. (NCI Thesaurus)