Carfilzomib is a derivative of the microbially-derived natural product epoxomycin. It irreversibly inhibits the chymotrypsin-like activity of the 20S proteasome with high potency and selectivity at several orders of magnitude over epoxomycin. In 2012, Carfilzomib was approved by the FDA for use in patients with relapsed and refractory multiple myeloma. It is in clinical trials for other cancers as well
