Long-term CR Multiple Myeloma Patients Show Cured or MGUS-like Minimal Residual Disease Pattern by Next Generation Flow

Background In the era of novel agents, many multiple myeloma patients can achieve a complete remission, but most of them relapse, and minimal residual disease detection can play a crucial role. Next-generation flow (NGF) can detect monoclonal plasma cells with a sensitivity of 10(-6.) Little is known about long-term remission patients (> 2 years) and in particular, if more sensitive techniques such as NGF can still detect minimal disease in those patients. Objective Aim of the study was to analyze patients with MM in response to NGF at > 2 years of sustained remission after several treatments. Methods MRD was studied by NGF in bone marrow aspirates according to Euroflow Consortium indications. Results 62 patients with sustained CR at >2 years were studied, MRD+ status was detected at a threshold cut-off of 10(-6) in 32/62 (52%); 4/15 (27%) patients were MRD positive at >5 years of remission and they displayed a prevalence of normal vs abnormal monoclonal plasma cell immune-phenotype (MGUS-like). Conclusion NGF is a powerful technique to detect MRD. Myeloma patients in prolonged sustained complete remission can show in high percentage an MRD negative status or MGUS like.