The purpose of this study is to find the highest dose of an investigational drug called SAR650984 that can be given safely in combination with lenalidomide and dexamethasone in patients with multiple myeloma that is not responding to standard therapy or has returned after therapy. SAR650984 is designed to stop the growth of some blood cancers (such as multiple myeloma) by attaching to a protein called CD38.
Lenalidomide and dexamethasone are both used in the standard treatment of multiple myeloma. Researchers will also observe the preliminary effectiveness of combining these drugs with SAR650984 in patients with multiple myeloma. SAR650984 is given intravenously (by vein), while lenalidomide and dexamethasone are taken orally (by mouth).