GPT and plasma cell myeloma: Eligible patients were 18 years of age or older with a prior diagnosis of multiple myeloma and measurable disease per International Myeloma Working Group (IMWG) criteria, adequate bone marrow (platelets ≥25 × 109 l−1, absolute neutrophil count ≥1.0 × 109 l−1, hemoglobin ≥8 g dl−1), hepatic (total bilirubin ≤2× upper limit of normal (ULN; ≤3x ULN if documented Gilbert’s syndrome), aspartate aminotransferase ≤2.5× ULN and ≤2.5× ULN alanine aminotransferase) and renal (creatinine clearance ≥30 ml min−1) function, and an Eastern Cooperative Oncology Group (ECOG) performance status ≤2.