A phase II multicenter trial was conducted to analyze the efficacy and safety of a bortezomib-containing regimen for induction prior to autologous stem cell transplantation (ASCT) in newly-diagnosed multiple myeloma Japanese patients under the age of 65. The induction regimen consisted of one cycle of vincristine-doxorubicin-dexamethasone followed by 3 cycles of twice-weekly bortezomib-dexamethasone (BD). Responding patients underwent stem cell harvesting and ASCT. The primary endpoint was the post-induction response rate (RR). Forty-one patients were enrolled from September 2009 to December 2012. Post-induction RR was 85.4% including 17.1% CR, 4.9% nCR, and 34.1% VGPR. Three-year progression-free and overall survival were 51.9% and 90.3%, respectively. During induction, grade ≥3 hematologic adverse events (AEs) were frequent, of which infection was the most prevalent: 2 events during VAD and 7 events during BD. A total of 8 patients (19.5%) dropped out during induction due to AEs. Furthermore, 15 patients dropped out prior to ASCT, 10 of whom were due to AEs. Only 26 patients (63.4%) proceeded to ASCT, resulting in a relatively low RR after ASCT (58.5%, including 14.6% CR, 17.1% nCR, and 12.2% VGPR). Clinicians must be wary of possible serious AEs, both during and after BD induction, when applied to Japanese patients.

The role of allogeneic hematopoietic stem cell transplantation (allo-SCT) for multiple myeloma (MM) has not yet been established. We performed allo-SCT on 16 patients with MM in our hospital and an associated center, and retrospectively evaluated its efficacy. The median age at allo-SCT was 47 years. Eight patients underwent allo-SCT as a front-line therapy. Non-myeloablative treatment was provided for 14 patients. The overall survival (OS) and progression-free survival (PFS) rates 3 years after transplantation were 72.9% and 37.5%, respectively, in patients who received front-line therapy, and were significantly higher than those in patients who received allo-SCT as salvage therapy (both P < 0.05). Transplant-related mortality at 3 years was 31.3%. Seven out of the 16 patients survived, and 4 patients who underwent allo-SCT as front-line therapy without maintenance showed relapse as an extramedullary mass, which was controlled by external radiation, and survived long-term, having a mean OS of 7.8 years. In our study, the OS and PFS recieved allo-SCT were not superior to those recieved more common therapies, such as autologous stem cell transplantation or combined chemotherapy with new agents. We need to have more progress in allo-SCT for MM while establishing safe and effective procedures.

CD56 is frequently expressed by malignant plasma cells in patients with multiple myeloma (MM) or AL amyloidosis (ALA). The aim of this retrospective study was to examine CD56 expression in patients with MM or ALA and determine the clinical and laboratory characteristics associated with its expression. Bone marrow samples of patients were analyzed by flow cytometry. Various clinical data with regard to the expression or non-expression of CD56 were compared. In total, 316 patients (215 with MM and 101 with ALA) were included in the study. The CD56 expression rate was higher in patients with MM than that in those with ALA. Patients with MM had a median CD56 expression rate of 96.4%, and serum total protein levels were significantly higher in the CD56+ group (p < 0.001). Patients with ALA had a median CD56 expression rate of 1.9%, and serum lactate dehydrogenase levels were significantly higher in the CD56+ group (p = 0.033). These findings suggest that the CD56 expression rate differs in monoclonal plasma cells between patients with MM and ALA, and that M-protein secretions are increased in patients with CD56+ MM.