Carfilzomib is an epoxomicin derivate with potential antineoplastic activity. Kyprolis (carfilzomib's trade name) is a proteasome inhibitor that is indicated for the treatment of patients with relapsed or refractory multiple myeloma who have received one or more lines of therapy as a single agent or in combination with dexamethasone or with lenalidomide plus dexamethasone. Carfilzomib is made up of four modified peptides. It irreversibly and selectively binds to N-terminal threonine-containing active sites of the 20S proteasome, the proteolytic core particle within the 26S proteasome. This 20S core has 3 catalytic active sites: the chymotrypsin, trypsin, and caspase-like sites. Inhibition of the chymotrypsin-like site by carfilzomib (β5 and β5i subunits) is the most effective target in decreasing cellular proliferation, ultimately resulting in cell cycle arrest and apoptosis of cancerous cells. At higher doses, carfilzomib will inhibit the trypsin-and capase-like sites. 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.