Inclusion Criteria:  Patients with relapsed or refractory multiple myeloma, with 1 to 3 therapies Must have received prior lenalidomide therapy and progressed on either a lenalidomide-containing regimen or lenalidomide maintenance (defined as a dose of 10-15 mg lenalidomide daily after induction regimen or maintenance)  Must have measurable disease, as defined by International Myeloma Working Group criteria, having one or more of the following:  Serum M protein >= 1.0 g/dL Urine M protein >= 200 mg/24 hours Involved serum free light chain level >= 10 mg/dL with abnormal kappa/lambda ratio Measurable biopsy-proven plasmacytomas (>= 1 lesion has a single diameter >= 2cm) Bone marrow plasma cells >= 30% Age 18 years and older, and have the capacity to give informed consent Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 Subjects should have resolution of any toxicities from prior therapy to grade =< 1 or baseline prior to enrollment (with the exception of peripheral neuropathy) Subjects are required to have grade =< 2 peripheral neuropathy to enroll Prior autologous stem cell transplant is allowed; patients must be >= 6 months post- autologous stem cell transplantation to enroll Estimated glomerular filtration rate (eGFR) >= 20 ml/min Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) =< 3 x upper limit of normal (ULN) Total bilirubin =< 2 x ULN Absolute neutrophil count (ANC) >= 1,000/uL Platelets >= 50,000/uL Hemoglobin >= 8 g/dL Growth factor use or transfusions may be used to meet the eligibility requirement for ANC, platelets, and hemoglobin Female patients of childbearing potential and male patients must agree to use 2 effective forms of contraception or continuously abstain from heterosexual intercourse during the period of therapy, and for 6 months after discontinuation of study treatment for females and 3 months after discontinuation of study treatment for males  Exclusion Criteria:  History of clinically significant cardiovascular disease, including congestive heart failure New York Heart Association (NYHA) class 3-4, symptomatic ischemia, left ventricular ejection fraction < 40%, uncontrolled conduction abnormalities, myocardial infarction in last 6 months Uncontrolled hypertension as determined by the principal investigator (PI) or designee Active plasma cell leukemia or systemic amyloid light-chain (AL) amyloidosis History of another primary malignancy that has not been in remission for at least 1 year (with the exception of non-melanoma skin cancer, curatively treated localized prostate cancer, curatively treated superficial bladder cancer and cervical carcinoma in site on biopsy or a squamous intraepithelial lesion on papanicolaou [PAP] smear) Active hepatitis B, hepatitis C at time of screening Subjects with active uncontrolled infection Concurrent use of other anticancer agents or experimental treatments Treatment with anti-CD38 monoclonal antibody therapy in the last 6 months