Minimal residual disease detection in multiple myeloma: comparison between BML single-tube 10-color multiparameter flow cytometry and EuroFlow multiparameter flow cytometry

Minimal residual disease (MRD)-negative status in multiple myeloma (MM) is associated with favorable outcomes. Although EuroFlow next-generation flow (NGF) is a global standard for MRD detection, its operating cost is high. Therefore, it is desirable to develop a less expensive method with equivalent sensitivity to that of EuroFlow-NGF. In this study, we compared the analytical ability of our BML 10-color multiparameter flow cytometry (MFC) to that of EuroFlow-NGF. Bone marrow samples collected from 51 patients with MM were subjected to MRD detection using BML 10-color-MFC and EuroFlow-NGF. Our antibody panel consisted of CD38 multiepitope, CD138, CD45, CD56, CD19, CD27, CD81, CD117, cytoplasmic immunoglobulin (cIg) κ, and cIgλ in a single tube. The median percentages of total plasma cells, as per 10-color-MFC and EuroFlow-NGF, were 0.2148% and 0.2200%, respectively, with a good correlation between the methods (r = 0.950). The median percentages of myeloma cells determined via 10-color-MFC and EuroFlow-NGF were 0.0012% and 0.0007%, respectively, with a strong correlation (r = 0.954). Our 10-color-MFC demonstrated high sensitivity to detect MRD; the results showed a good correlation with those obtained using EuroFlow-NGF. Therefore, our cost-effective single-tube MFC (approximately 100 USD/sample) is a promising alternative method for the detection of MRD in patients with MM.

[Cost-effectiveness of peripheral blood stem cell collection using plerixafor: a single-center study]

Plerixafor is increasingly used in combination with granulocyte-colony-stimulating factor (G-CSF) for peripheral blood stem cell collection. Although it is an expensive drug, its cost-benefit performance is not well investigated. Thus, we analyzed its cost-effectiveness in our hospital. A retrospective observational analysis was performed in patients who underwent stem cell collection between December 2013 and November 2018. A total of 203 patients were investigated and classified into three groups according to their pre-mobilization regimen: G-CSF alone, G-CSF and cyclophosphamide (G+CY), and G-CSF and plerixafor (G+plerixafor). The cost-effectiveness of apheresis of the collected cluster of differentiation (CD) 34+ cells was assessed based on two viewpoints: cost of drugs and cost of equipment. Due to the high cost of plerixafor, the cost of apheresis was higher in patients who received G+plerixafor. However, the difference narrowed when we calculated the cost to collect 2.0×10⁶ CD34+ cells/kg body weight required for a single transplant. The number of stem cells collected from patients who received G+plerixafor was higher than those who received other regimens (median CD34+ cells harvested/day were 2.90 for G-CSF, 2.13 for G+CY, and 4.63 for G+plerixafor, ×10⁶/kg body weight, P<0.01). Our results show that plerixafor enables efficient apheresis.

[Elotuzumab treatment for a multiple myeloma patient relapsing after allogenic stem cell transplantation]

Although elotuzumab (ELO) is associated with improved outcomes in patients with relapsed/refractory multiple myeloma (MM), no data are available for the usage of ELO following allogeneic stem cell transplantation (allo-SCT). Here, we report two cases of relapsed MM treated with ELO in combination with lenalidomide (LEN) and dexamethasone (ELd) following allo-SCT. Case 1 had been treated with 11 lines of therapy followed by cord blood transplantation resulting in partial response. ELd was introduced 140 days post-transplantation and continued for eight cycles until disease progression. No worsening in graft-versus-host disease (GvHD) was observed under ELd treatment. Case 2 had received unrelated bone marrow transplantation due to primary refractory disease after undergoing six regimens. Carfilzomib-based maintenance therapy had to be discontinued owing to severe myelosuppression. Subsequently, ELd treatment was initiated 544 days following the allo-SCT, which led to an improvement in serum paraprotein level and amelioration in GvHD. In both cases, immunosuppressants were tapered off. Several studies have shown exacerbation of GvHD under LEN monotherapy following allo-SCT. However, an ELd regimen may be one of the safer options for treating post-allo-SCT relapse.

The efficacy and safety of modified bortezomib-lenalidomide-dexamethasone in transplant-eligible patients with newly diagnosed multiple myeloma

OBJECTIVES

Bortezomib with lenalidomide and dexamethasone (VRd) is a standard induction regimen for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). However, some patients discontinue VRd because of severe adverse events, despite its high efficacy. We aimed to study the efficacy of modified dose of VRd (VRd lite) in transplant-eligible patients with NDMM.

METHODS

Forty-eight transplant-eligible patients with NDMM were included. VRd lite was administered every 4 weeks. Bortezomib 1.3 mg/m² was administered subcutaneously on days 1, 8, 15 and 22, and dexamethasone 20 mg was administered orally on the day of and the day after bortezomib administration. Lenalidomide was omitted on days 1, 8 and 15, which are the days of bortezomib administration.

RESULTS

The overall response rate (ORR) after four cycles of VRd lite was 83%, including a complete response of 25%. Thirty-eight among the 45 patients who completed at least four cycles of VRd lite received autologous stem cell transplantation (ASCT). The ORR and very good partial response or better were upgraded to 100% and 74%, respectively, following ASCT.

CONCLUSION

Our strategy consisting of VRd lite followed by ASCT is, thus, a highly effective and well-tolerated regimen resulting in durable responses in patients with NDMM.

Red blood cell distribution width is a simple and novel biomarker for survival in light-chain amyloidosis

Red blood cell distribution width (RDW) has been used for the differential diagnosis of anemia, but high RDW may also be associated with several human disorders. We evaluated the prognostic relevance of RDW in patients with light-chain (AL) amyloidosis. We retrospectively analyzed all patients with AL amyloidosis who were newly diagnosed at the Japanese Red Cross Medical Center between December 2011 and June 2018. RDW was evaluated in 94 patients; 48% (n = 45) of patients had a high RDW (≥ 13.8%) and 52% (n = 49) had a low RDW (< 13.8%). Overall survival (OS) was significantly lower in patients with a high RDW (P < 0.001). On multivariate analysis, increased RDW was an independent predictor for OS. Even in patients without cardiac amyloidosis, the OS was significantly lower in the high-RDW group (P = 0.0064). The survival rate of high-RDW patients without cardiac involvement was as poor as that of patients with cardiac involvement. In addition, in patients with revised Mayo stage I or a normal level of N-terminal pro-B-type natriuretic peptide, high RDW was negatively correlated with OS (P = 0.0086, 0.025). RDW is a simple and strong predictor of early death, and is a prognostic biomarker in patients with AL amyloidosis without cardiac involvement.

[Efficacy of plerixafor in autologous peripheral blood stem cell collection]

Failure of autologous peripheral blood stem cell collection (PBSCH) can affect the treatment modality for patients with hematological malignancies. The clinical efficacy of plerixafor in PBSCH was analyzed in our institution. The medical records of 61 patients were retrospectively reviewed. The use of plerixafor was determined according to the CD34⁺ cell count in the peripheral blood (PB CD34⁺) on day 4 of G-CSF administration and patients' backgrounds. A total of 47 patients received G-CSF plus plerixafor: 31 with multiple myeloma, 8 with AL amyloidosis or POEMS syndrome, and 8 with non-Hodgkin lymphoma. The median fold increase in PB CD34⁺ following the first dose of plerixafor was 7.18 times. The median number of collected CD34⁺ cells on day 5 was 4.1×10⁶/kg and 5.3×10⁶/kg in total. Among the 47 patients, 44 (93.6%) yielded the minimum required cell collection of 2.0×10⁶/kg within an average of 1.3 days. Plerixafor enables rapid and efficient mobilization, and sufficient numbers of CD34⁺ cells were successfully collected.

[Clinical characteristics of young multiple myeloma patients: a single-center analysis of 30 patients]

Because multiple myeloma is rare in young people, there are fewer reports on the same. Thus, its clinical aspects and prognosis remain unelucidated. We retrospectively evaluated 30 patients with multiple myeloma aged ≤ 45 years at diagnosis. We divided them into three groups based on their cytogenetic risks: standard risk (SR), high risk (HR), and unknown risk. The frequency of HR patients was 36.6%, the highest of the three groups, unlike the previous report. The median progression-free survival (PFS) was 35 months (SR vs. HR, 46 vs. 29 months), and the median overall survival (OS) was not reached (NR) (SR vs. HR, NR vs. 82 months). The OS was significantly worse, and the PFS also appeared inferior in HR patients. The International Staging System score was not associated with OS. Thus, young patients with myeloma appeared to have a higher frequency of HR features, suggesting that instead of age, the cytogenetic risk was a significant prognostic factor.