Additional Study Information: This is a research study for subjects who have been diagnosed with multiple myeloma, a cancer of plasmacells (a type of immune cell that produce antibodies) in the bone marrow, that has returned (relapsed) or has not responded (refractory) to your most recent treatment regimen.The subject's disease has also progressed after prior treatment with lenalidomide (Revlimid).The main purpose of this research study is to evaluate the safety and determine the maximum tolerated dose of two investigational new drugs, carfilzomib and pomalidomide, in combination with dexamethasone in subjects with relapsed or refractory multiple myeloma.