The recent FDA approval of single-agent carfilzomib (Kyprolis) adds to the armamentarium of agents for the treatment of relapsed and refractory multiple myeloma. Carfilzomib was approved based on an open-label, single-arm study of single-agent carfilzomib after the failure of at least 2 previous therapies. Within the inclusion criteria, the subjects were required to have failed bortezomib. Although bortezomib and carfilz­omib are both proteasome inhibitors, carfilzomib selectively and irreversibly binds to its target, which results in sustained proteasome inhibition that is absent of off-target effects relative to bortezomib.^1,2 Read More ›