RecruitingPhase 2Drug trialA Study of CyBorD (Cyclophosphamide, Bortezomib, Dexamethasone) Plus Daratumumab in People With Monoclonal Gammopathy of Renal Significance (MGRS)The purpose of this study is to find out whether cyclophosphamide, bortezomib, dexamethasone (CyBorD) with daratumumab SC is a safe treatment combination for MGRS-associated kidney disease including cast nephropathy associated with multiple myeloma. In addition, the researchers will find out whether the study drug combination is an effective treatment for these conditions.