Bortezomib (BAN, INN and USAN; marketed as Velcade by Millennium Pharmaceuticals; Neomib by Getwell and Bortecad by Cadila Healthcare) is an anti-cancer drug and the first therapeutic proteasome inhibitor to be used in humans. Proteasomes are cellular complexes that break down proteins. In some cancers, the proteins that normally kill cancer cells are broken down too quickly. Bortezomib interrupts this process and lets those proteins kill the cancer cells. It is approved in the U.S. and Europe for treating relapsed multiple myeloma and mantle cell lymphoma. In multiple myeloma, complete clinical responses have been obtained in patients with otherwise refractory or rapidly advancing disease.