Following on from the success of the approved first-generation proteasome inhibitor Velcade (bortezomib, Millennium/Takeda Pharmaceutical Co. Ltd.), which jams up the proteasome and nonspecifically inhibits proteins from being degraded, various new proteasome inhibitors are currently in development, including peptide boronic acid analogue MLN9708 (Millennium/Takeda) and carfilzomib (Onyx Pharmaceuticals Inc.).