The bone marrow (BM) milieu confers drug resistance in multiple myeloma (MM) 
cells to conventional therapies. Novel biologically based therapies are 
therefore needed. Preclinical studies have identified and validated molecular 
targeted therapeutics in MM. In particular, recognition of the biologic 
significance of the BM microenvironment in MM pathogenesis and as a potential 
target for novel therapeutics has already derived several promising approaches. 
Thalidomide, lenalidomide (Revlimid), and bortezomib (Velcade) are directed not 
only at MM cells but also at the BM milieu and have moved rapidly from the bench 
to the bedside and United States Food and Drug Administration approval to treat 
MM.