Patients
MM
Eligible participants were enrolled in this study. Key inclusion criteria were as follows: participants' age: 18–75 years; previous treatment with two or more regimens for MM and not considered for bone marrow transplantation; M-protein levels needed to meet at least one of the following criteria: serum M-protein ≥ 10 g/L (IgG, IgM, IgD subtype), or ≥ 7.5 g/L (IgA subtype), or urinary M-protein ≥ 200 mg/24 h; absolute neutrophil count ≥ 1.0 × 10