New drugs in multiple myeloma: mechanisms of action and phase I/II clinical findings.

The outcome of multiple myeloma has substantially improved over the past decade, mainly due to recently approved drugs, such as thalidomide, lenalidomide, and bortezomib. Nevertheless, most patients still relapse and, therefore, drugs with new mechanisms of action are urgently needed to overcome this resistance. In this Review, we discuss some of the new targeted therapeutic strategies under assessment in preclinical and clinical studies in multiple myeloma. Unfortunately, the single-agent clinical activity of most of these new drugs has been limited; nevertheless, their effectiveness might be enhanced by their rational combination with each other or with conventional agents.