Primary Multiple Myeloma Who Achieved MRD Negativity After Induction Therapy, ASCT or Not

Inclusion Criteria: 1. Newly diagnosed multiple myeloma according to the criteria of International Working Group of Myeloma 2. Age ranges from 18-70 years old 3. Achieved MRD negativity and at least very good partial response in clinical response after 4-6 courses of induction therapy. MRD is measured by MRD by multicolor flow with a sensitivity of 10-5. 4. At enrollment, score of Eastern Cooperative Oncology Group (ECOG) should be 0-2. 5. Organ function requirement: Blood bilirubin ≤ 2mg/dL (35 μ mol/L), Alanine aminotransferase/Aspartate aminotransferase below 2 times the upper limit of normal value, Creatinine clearance rate (Ccr) ≥ 30ml/min and Cardiac ejection fraction ≥50%. 6. Expected survival more than 3 months. Exclusion Criteria: 1. Two or more high-risk cytogenetic abnormalities, including del (17p), t (4; 14), t (14; 16), del (1p), amp (1q). Fluorescence in situ hybridization was used to analyze CD138 positive sorted cells, with cut off value of 15% for translocation, 10% for deletion, and amp (1q) of 20%. 2. Extracellular plasma cell disease, central invasion of myeloma, plasma cell leukemia 3. History of other malignant tumors within the past 5 years 4. Patients with HIV, active tuberculosis, clinically active hepatitis A, B, or C 5. Other serious condition that may restrict patients from continuing treatment (such as advanced infection, uncontrolled diabetes, severe cardiac insufficiency, or angina pectoris) 6. General condition not suitable for chemotherapy 7. Pregnant or lactating women 8. Suffering from other serious organic diseases and mental disorders.