Identification of clonal immunoglobulin λ light-chain gene rearrangements in AL amyloidosis using next-generation sequencing.

Amyloid light-chain (AL) amyloidosis is caused by deposition of abnormally folded clonal immunoglobulin (Ig) light chains made by malignant plasma cells in the bone marrow (BM), leading to multiorgan dysfunction. However, little is known of the factors that regulate the organ tropism of amyloid deposition in this disease. We aimed to identify the clonal composition of Igλ light-chain variable region (IGLV) genes in BM cells in patients with AL amyloidosis using next-generation sequencing. Based on our definition of the clonal IGLV rearrangement (dominant clone >2.5%, dominant cluster >5%), we identified clonal IGLV in 33 of 38 patients with AL amyloidosis (86.8%), 6 of 9 with monoclonal gammopathy of undetermined significance (67%), and 7 of 7 with multiple myeloma (100%). The clones in AL amyloidosis were significantly smaller than those in multiple myeloma (p < 0.01) but comparable to those in monoclonal gammopathy of undetermined significance. Importantly, in patients with AL amyloidosis, the difference in involved and uninvolved free light chains was not correlated with the clonal size of BM plasma cells in our repertoire analysis using NGS. In summary, the clonal composition of IGLV genes in the BM was successfully identified in most patients with AL amyloidosis using NGS. The clonal size of plasma cells in the BM is small, and small malignant clones of plasma cells may secrete free light chi and cause light chain depositions in AL amyloidosis.

[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.

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.

[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.

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.

Autologous Hematopoietic Cell Transplantation Versus Chemotherapy Alone for Immunoglobulin Light Chain Amyloidosis: A Retrospective Study.

INTRODUCTION: Immunoglobulin light chain (AL) amyloidosis is caused by the deposition of monoclonal immunoglobulin light chains, for which autologous hematopoietic cell transplantation (AHCT) is one of the most effective therapies. In small studies comparing AHCT with chemotherapy alone, AHCT was associated with better survival. PATIENTS AND METHODS: In this study, we compared the outcomes of AHCT with those of chemotherapy alone in 232 patients. We retrospectively reviewed the outcomes in 74 patients who underwent AHCT with those of 158 patients treated only with chemotherapy. RESULTS: The median event-free survival (EFS) (73 vs. 9 months; P < .001) and overall survival (OS) (not achieved vs. 39 months; P < .001) were superior in the AHCT group versus those in the chemotherapy group. On multivariate analysis, AHCT was significantly associated with better EFS (hazard ratio, 0.410; 95% confidence interval, 0.241-0.697; P = .0010) and OS (hazard ratio, 0.313; 95% confidence interval, 0.155-0.636; P = .0013) than chemotherapy alone. Even when patients with severe findings (mean left ventricular thickness > 12 mm, brain natriuretic peptide level > 400 pg/mL, and creatinine level > 2.0 mg/dL) and elderly patients (age > 65 years) were excluded, both EFS and OS were significantly better in the AHCT group than in the chemotherapy group upon univariate and multivariate analyses. CONCLUSION: AHCT yielded better EFS and OS than chemotherapy alone in patients with AL amyloidosis. AHCT should be considered for eligible patients.

[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.

Poor mobilizer and its countermeasures.

Mobilization failure is a major concern in patients undergoing hematopoietic cell transplantation, especially in an autologous setting, as almost all donor harvests can be accomplished with granulocyte-colony stimulating factor (G-CSF) alone. Poor mobilizers, defined as those with a peripheral blood CD34+ cell count ≤20 cells/µl after mobilization preceding apheresis is a significant risk factor for mobilization failure. We recommend preemptive plerixafor plus G-CSF (filgrastim, 10 µg/kg daily) as a first mobilization strategy, which yields sufficient peripheral blood progenitor cells (PBPCs) in almost all patients and avoids otherwise unnecessary remobilization. Preemptive plerixafor is administered in patients with a day-4 peripheral blood CD34+ count <15, depending on the disease and the target PBPC amount. Cyclophosphamide is reserved for patients who fail the first PBPC collection. We recommend second mobilization for patients who could not achieve a sufficient PBPC amount with the first mobilization. In these patients, a second attempt with plerixafor plus G-CSF or mobilization with plerixafor in combination with cyclophosphamide and G-CSF is recommended. Increased dose and/or twice daily administration of G-CSF can be considered.

[Carfilzomib, lenalidomide, and dexamethasone therapy for refractory and relapsed multiple myeloma: a single-center study of 29 patients].

Twenty-nine patients with multiple myeloma were treated with carfilzomib, lenalidomide, and dexamethasone (KLd) therapy. A response better than partial response (PR) was observed in 72.4% patients with relapsed and/or refractory myeloma. Although 13.8% patients developed hypertension, none of them discontinued therapy as they could be managed by appropriate medication. A patient who had an elevated level of BNP prior to initiating KLd therapy developed heart failure. Results from this study demonstrate that KLd therapy is efficacious for treating patients with multiple myeloma; however, they should be carefully monitored for cardiotoxicity.

Abnormal Heavy/Light Chain Ratio and Matched Pair Suppression Increase Residual Disease Detection Sensitivity in Patients With Multiple Myeloma With Deep Responses.

BACKGROUND: Heavy/light chain (HLC) assay can quantify involved as well as uninvolved immunoglobulin pairs and is used to detect monoclonal proteins. PATIENTS AND METHODS: We compared the sensitivity between HLC assay and serum protein electrophoresis, serum immunofixation electrophoresis (IFE), and free light chain (FLC) assay in patients with symptomatic multiple myeloma (n = 111) whose responses were stable disease or better. RESULTS: Among patients with negative IFE and normal FLC ratios, 84.4% (38 of 45) and 80% (36 of 45) exhibited normal HLC ratios and no pair suppression, respectively (13.3% [6 of 45], moderate pair suppression and 6.7% [3 of 45], severe pair suppression). The lower the monoclonal protein levels, the more the possibility that the patients had normal HLC ratios and no matched pair suppression (both P < .000001). HLC ratios or pair suppression combined with IFE results and FLC ratios were more sensitive for detecting monoclonal proteins than were IFE results and FLC ratios alone (P = .016 and .0039, respectively). A combination of all 4 methods (IFE, FLC, HLC, and pair suppression) was far more sensitive than were IFE findings plus FLC ratios alone (P = .00024). CONCLUSION: Abnormal HLC ratios and HLC-matched pair suppression can increase the sensitivity for detecting residual disease in patients with multiple myeloma with deep responses.

[IgE-κ type multiple myeloma achieving complete response with novel agents].

IgE multiple myeloma (MM) is a rare subtype of MM characterized by an aggressive and poor prognosis. Although novel agents have improved the prognosis of MM, there are few case reports of IgE MM treated with these agents. A 53-year-old male patient presented with pain in the right rib and was diagnosed with IgE-κ MM. He was treated with multidrug chemotherapy, including bortezomib and lenalidomide, and underwent autologous stem-cell transplantation (ASCT). Finally, he achieved a complete response after the initiation of pomalidomide. In previous reports, majority of patients with refractory IgE MM treated with novel agents had a poor prognosis. In contrast, patients who were treated with novel agents from the beginning and underwent ASCT had a long-term survival. Overall, the use of novel agents as the first-line therapy is expected to improve IgE MM prognosis.

Efficacy and Safety of Doubly-Regulated Vaccinia Virus in a Mouse Xenograft Model of Multiple Myeloma.

Multiple myeloma is a malignancy of plasma cells of the bone marrow. Although the prognosis is variable, no curative therapy has been defined. Vaccinia virus infects cancer cells and kills such cells in a variety of ways. These include direct infection, triggering of immunomediated cell death, and vascular collapse. The potential of the vaccinia virus as an anti-tumor therapy has attracted the attention of oncologists. Interestingly, our preliminary experiments revealed that myeloma cells were particularly susceptible to vaccinia virus. To exploit this susceptibility and to render vaccinia more myeloma specific, we generated thymidine-kinase-deleted microRNA (miRNA)-regulated vaccinia viruses in which the essential viral gene B5R was regulated by miRNAs of normal human cells. Of the miRNAs examined, let-7a was found to be the most reliable in terms of regulating viral transmission. Exposure to unregulated vaccinia virus killed myeloma-transplanted severe combined immunodeficiency (SCID) mice; the animals succumbed to viral toxicity. In contrast, the thymidine-kinase-deleted let-7a-regulated virus remained localized within myeloma cells, triggering tumor regression and improving overall survival. In conclusion, a thymidine-kinase-deleted let-7a-regulated vaccinia virus was safe and effective for mice, warranting clinical trials in humans.

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis during pregnancy.

An 11-week pregnant, 32-year-old Japanese woman who had recovered from infectious mononucleosis visited our center due to fever, anorexia, and bilateral hypochondrial pain. Blood tests revealed leukopenia, thrombocytopenia and elevated ferritin. She was diagnosed with hemophagocytic lymphohistiocytosis (HLH). A high viral load of the Epstein-Barr virus (EBV) was recognized, indicating EBV-HLH. She was treated with a single dose of dexamethasone to protect the fetus. However, the disease was uncontrollable, necessitating etoposide and cyclosporine administration. Remission was obtained with these medications, and she has remained in remission for the 10 months since completion of chemotherapy. Although the occurrence of EBV-HLH during pregnancy is rare, it is possible that a change in cellular immunity associated with the pregnancy may contribute to EBV-HLH development.

Capillary electrophoresis/immunosubtraction as a better alternative to immunofixation for detecting and immunotyping serum monoclonal proteins in patients with immunoglobulin light chain (AL) amyloidosis.

Capillary electrophoresis/immunosubtraction (CE/IS) is a simple method for detecting and immunotyping serum or urine monoclonal proteins. To our knowledge, there are no previous reports of the use of CE/IS for characterizing patients with Immunoglobulin light chain (AL) amyloidosis, and there are no convincing data available to compare CE/IS with serum immunofixation electrophoresis (IFE) and free light chain (FLC) assay. The aim of this study was to evaluate the clinical utility of CE/IS in patients with AL amyloidosis as a diagnostic accuracy study. This study included 50 patients with AL amyloidosis (17 newly diagnosed and 33 undergoing treatment). Serum IFE identified monoclonal proteins in 15/50 (30%) of all cases and in 7/17 (41%) of newly diagnosed cases. CE/IS identified monoclonal proteins in 16/50 (32%) of all cases and in 7/17 (41%) of newly diagnosed cases. The FLC assay detected an abnormal ratio of kappa and lambda light chains in 26/50 (52%) of all cases and in 15/17 (88%) of newly diagnosed cases. IFE and CE/IS combined with FLC assay identified monoclonal proteins more sensitive than IFE alone and CE/IS alone, in newly diagnosed patients (p = 0.002 and 0.002, respectively) and in patients undergoing treatment (p = 0.031 and 0.016, respectively). CE/IS is an acceptable alternative to IFE.

Clinical usefulness of WT1 mRNA expression in bone marrow detected by a new WT1 mRNA assay kit for monitoring acute myeloid leukemia: a comparison with expression of WT1 mRNA in peripheral blood.

We have previously shown the clinical usefulness of Wilms' tumor 1 gene (WT1) mRNA expression in peripheral blood (PB) as a minimal residual disease (MRD) monitoring marker in 191 acute myeloid leukemia (AML) patients using the WT1 mRNA assay kit "Otsuka" (Otsuka Pharmaceutical Co., Ltd.; "former kit"). In contrast, the usefulness of WT1 mRNA expression in bone marrow (BM) has been investigated in only a limited number of subjects using former kit. Following that previous study, a next-generation kit, WT1 mRNA assay kit II "Otsuka" (Otsuka Pharmaceutical Co., Ltd.; "new kit") has been newly developed. In the present study, we aimed to evaluate the performance of the new kit and to investigate the clinical usefulness of WT1 mRNA expression in BM. The PB and BM were collected on the same day from 164 blood disease patients, including 118 AML patients. WT1 mRNA expression was determined using the new and former kits and the values obtained were compared. The performance of new kit was shown to be equivalent to that of former kit. As reported in PB, WT1 mRNA expression in BM was found to be a useful marker for monitoring disease status as well as for a diagnosis of early stage relapse in AML patients.

High-dose melphalan and autologous stem cell transplantation for systemic light-chain amyloidosis: a single institution retrospective analysis of 40 cases.

We report our retrospective analysis of 40 patients who received high-dose melphalan and autologous stem cell transplantation for systemic immunoglobulin light-chain (AL) amyloidosis. Between 2006 and 2013, 40 patients with AL amyloidosis were transplanted at our medical center. Their median age was 54 years (range 32-70 years): 18 were male. The dominant organs involved were the heart in 13 patients, and kidney in 22: and other organs were involved in five. The median melphalan dose administered was 129 (range 50-200) mg/m(2), and the median infused CD34(+) cells was 2.69 (range 1.17-11.26) × 10(6)/kg. Of the 40 patients, 30 are alive after a median follow-up of 42 (range 12-94) months, and the 4-year estimated overall survival rate was 74% (95% CI 56-86%). Four patients died ≤ 100 days post-ASCT (heart failure in three patients, bacteremia in one). The 4-year estimated survival of the patients with cardiac involvement was 54%, significantly lower than that of the other patients (91%). Hematological and organ responses were 52 and 50%, respectively. Careful patient selection and experienced management are important, especially for patients with cardiac involvement. It is also important to develop additional treatment for patients who do not achieve a hematological and/or organ response.

[The clinical significance of decrease in CD138 positive cell ratio in multiple myeloma].

CD138 has been considered to be strongly expressed in multiple myeloma cells. However, CD138⁺ cells were decreased in some patients during the course of treatment. To clarify the clinical significance of this finding, we evaluated the correlations of CD138 levels with laboratory data employing flow cytometry. We found that CD138⁺ cells were decreased in 12 patients during treatment and were retained in the remaining 105 patients throughout their clinical courses. For nine (75%) patients in the CD138⁺ cells reduced group, median survival time was 25 months after the reduction in CD138⁺ cells was detected, and all nine died of myeloma. Furthermore, extramedullary lesions and specific cytogenetic abnormalities [del(17p), t(4;14), amplification of c-MYC] were observed in some patients when the number of CD138⁺ cells started to decrease. Interestingly, 2 of 3 patients who survived until the end of observation period showed re-increase in their CD138⁺ levels. Taking these observations together, it is unclear whether reduction of the number of CD138⁺ cells is associated with a poor prognosis and resistance to drugs. However, if treatment does not produce a reincrease in CD138⁺ levels, long term survival might be difficult to achieve.