A drug used with lenalidomide and dexamethasone to treat multiple myeloma. It is used in patients whose cancer was treated with one to three anticancer therapies. Elotuzumab binds to a protein called CS1, which is found on myeloma cells and some types of immune cells. Elotuzumab may block CS1 and help the immune system kill cancer cells. It is a type of monoclonal antibody. Also called Empliciti and HuLuc63. OR A humanized monoclonal antibody directed against the human CS1 (CD2 subset 1, CRACC, SLAMF7) antigen with potential antineoplastic activity. Elotuzumab binds to the CS1 antigen, which may trigger antibody-dependent cellular cytotoxicity (ADCC) in cells expressing CS1. CS1 is a cell surface glycoprotein belonging to the CD2 subset of the immunoglobulin superfamily (IgSF) and is highly expressed by multiple myeloma cells, but minimally expressed by normal cells.