Study to Assess for Measurable Residual Disease (MRD) in Multiple Myeloma Patients

This study is to assess for Measurable Residual Disease (MRD) in multiple myeloma at a deeper level than what is currently available by combining novel imaging and laboratory techniques, determine if patients who are MRD-negative by these multiple modalities can safely and effectively discontinue post-transplant maintenance therapy, and determine if liquid biopsies is a more accurate and/or less invasive sampling technique for multiple myeloma. The purpose of this research is to determine if patients who are MRD-negative by multiple modalities ("multimodality MRD-negative") can safely and effectively discontinue post-transplant maintenance therapy (single agent lenalidomide, pomalidomide, bortezomib, or ixazomib) after receiving at least one year of maintenance therapy.