scholarly journals Detection and Characterization of Plasma Cell and B Cell Clones in Patients with Systemic Light Chain Amyloidosis Using Flow Cytometry

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2068-2068
Author(s):  
Stefan Schönland ◽  
Ute Hegenbart ◽  
Christoph Kimmich ◽  
Katarina Lisenko ◽  
Dirk Hose ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
B Cell ◽  
Cell Count ◽  
Plasma Cell ◽  
Light Chain ◽  
Plasma Cells ◽  
Cell Clone ◽  
Flow Analysis ◽  
Al Amyloidosis ◽  
Cell Clones

Abstract Introduction: AL amyloidosis is a rare and life-threatening protein-deposition disorder caused by a small B cell (mostly plasma cell) clone which produces amyloidogenic light chains. The goal of therapy is to target this clone and halt the uncontrolled release of free light chain, which might subsequently lead to improvement of organ function. In routine diagnostic some of these B cell clones are missed as they might be extremely small. However, specific treatment can only be applied if the clone is well characterized. Hardly any data on the characteristics of these cells using flow cytometry have been reported. (e.g. Paiva et al., Blood 2011). Study design: We performed a retrospective analysis of consecutive patients who were referred to our amyloidosis center (March to July 2014) and have been thoroughly studied (immunhistology of amyloid, free light chain assay, immunofixation, bone marrow diagnostic: cytology, flow cytometry and interphase-FISH cytogenetics (iFISH)). Patients and Methods: Twenty-two patients were included (all untreated, 21 AL patients, one pt with monoclonal gammopathy of renal significance (MGRS)). Plasma cells were detected by their co-expression of CD38 and CD138 antigens. Differentiation between malignant and normal plasma cells was achieved by analysis of aberrant CD45 and CD19 expressions and proof of intracellular light chain restriction (see Figure 1). To evaluate potential targets for an antibody-based immunotherapy, we stained CD20, CD22, CD30, CD52 and CS-1 on these plasma cells. Overall, positivity was defined as >20% expression of the antigen. iFISH was done after CD138 selection as previously described (Bochtler et al., Blood 2011). Results: Main characteristics and results are shown in Table 1. Median dFLC was 304 mg/l, three patients had a dFLC of less than 50 mg/l. Median plasma cell count in cytology was 10%, 3 patients had less than 5%. Median plasma cell count by flow was 3.8%, three patients had less than 1%. Correlation between dFLC, plasma cell count in cytology and flow was low (FLC vs. flow: spearman=0.25, p=0.26; FLC vs. cytology: spearman=0.49, p=0.02; flow vs. cytology, spearman=0.36, p=0.1). Detection of the amyloidogenic clone by flow was possible in all but one patient (95%). In this patient we were not able to show a light chain restriction although we detected a relevant aberrant plasma cell clone (CD45low, CD19low). In one patient we found a B cell lymphoma as underlying disease for MGRS type IgG lambda (CD19+, CD20+, lambda+, CD5-, CD22+, FMC7-, CD23-, CD25+, CD103-, CD38+ typical for marginal zone lymphoma). In all 21 patients the light chain restriction demonstrated by flow was confirmed by immunofixation, FLC, and immunohistology of the amyloid. All patients analyzed for the expression of CS-1 were positive. 25% were also positive for CD20 and none was positive for CD22, CD30 and CD52. Detection of the plasma cell clone by iFISH was possible in all 21 patients (see Table 1). Conclusion: Flow cytometric analysis of the bone marrow is a very sensitive method to detect and characterize the amyloidogenic clone in AL amyloidosis. B cell lymphomas can easily be distinguished from pure plasma cell clones. Secondly, flow provides useful information to specify immune-chemotherapy in AL amyloidosis and related disorders. Table 1: Patients (n=22) Characteristics and Results Age in yrs (median / range) 67 (41 – 77) Sex: female / male 9 / 13 Type of light chain: kappa / lambda 4 / 18 Median dFLC in mg/l (range) 304 (22 - 6621) Median % of plasma cells in BM cytology (range) 10 (0 – 68) Underlying disease leading to AL amyloidosis“MG” / MM III / B-NHL 20 / 1 / 1 Median % of PC by flow (range) 3.8 (0.2 - 34) Detection of the amyloidogenic clone by flow 21 / 22 Flow analysis of clonal plasma cells (% of pts)CD20+ / CD22+ / CD30+ / CD52+ / CD56+ / CS-1+ 25 / 0 / 0 / 0 / 75 / 100 Detection of a clone by iFISH 21/21 % of pts with t(11;14) / Gain of 1q21 / Hyperdiploidy / High-risk cytogenetic (del 17p13, t(4;14)) 52 / 10 / 14 / 10 Figure 1: Representative flow analysis of one pt. with a lambda+, CD38+, CD138+ plasma cell clone (green). Polyclonal CD19+ B cells in red. Figure 1:. Representative flow analysis of one pt. with a lambda+, CD38+, CD138+ plasma cell clone (green). Polyclonal CD19+ B cells in red. Disclosures Schönland: Janssen: Honoraria; Celgene: Honoraria. Hegenbart:Janssen: Honoraria; Celgene: Honoraria. Hose:Novartis: Research Funding. Hundemer:Celgene: Honoraria, Research Funding.

scholarly journals Single Arm, Prospective, Open-Label Phase II Trial to Evaluate the Efficacy of Isatuximab in Patients with Monoclonal Gammopathy of Renal Significance

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3161-3161 ◽  
Author(s):  
Vikram Premkumar ◽  
Suzanne Lentzsch ◽  
Divaya Bhutani
Keyword(s):  
Multiple Myeloma ◽  
B Cell ◽  
Plasma Cell ◽  
Monoclonal Gammopathy ◽  
Plasma Cells ◽  
Cell Clone ◽  
Advisory Committees ◽  
Renal Response ◽  
Hematologic Response ◽  
Stable Renal Function

Background: Monoclonal gammopathy of renal significance (MGRS) is a monoclonal B cell disorder, not meeting the definition of lymphoma or myeloma, that produces monoclonal proteins which deposit in the kidneys. Permanent renal damage can occur either as a consequence of direct deposition of toxic proteins or by an induced inflammatory response. Due to the low burden of the plasma cell clone, patients do not otherwise qualify for potentially toxic anti-plasma cell treatments and treatment is generally based on consensus opinion. To date there are no clinical trials exploring treatment options. Isatuximab is a chimeric mouse/human IgG1k monoclonal antibody which targets CD38 on both malignant and normal plasma cells and exhibits it antitumor effects primarily by antibody-dependent cellular toxicity. Isatuximab has recently been shown to be an active drug in the treatment of multiple myeloma, with improvements seen in hematologic and renal markers, and has been shown to have manageable toxicity. Given the efficacy of isatuximab in multiple myeloma, we propose a trial evaluating isatuximab monotherapy to treat the small plasma cell clone in MGRS with the hopes of maximizing response and minimizing toxicity. Study Design and Methods: The primary objective of this study is to evaluate efficacy of isatuximab monotherapy in patients with MGRS in order to establish a standard of care treatment for patients with this disease. Adult patients with proteinuria of at least 1 gram in 24 hours and a histopathological diagnosis of MGRS on renal biopsy in the last 24 months will be eligible for the trial. Patients will be excluded if their estimated GFR is below 30 mL/min, they have multiple myeloma, high risk smoldering myeloma, other B cell neoplasm meeting criteria for treatment, concurrent diabetic nephropathy, or require dialysis. Patients will be screened for B cell disorders with bone marrow biopsy and aspirate, serum protein electrophoresis (SPEP) with immunofixation (IFE), 24-hour urine protein electrophoresis (UPEP), free light chain (FLC) testing and screening PET/CT at time of enrollment. Enrolled patients will be administered isatuximab 20 mg/kg IV weekly for 4 weeks and then will receive the same dose every 2 weeks thereafter for a total of 6 months. Patients may be continued on treatment following completion of the 6 months at the discretion of the provider. To reduce the risk of infusion related reactions, patients will receive premedications with corticosteroids, diphenhydramine, H2 blockade and acetaminophen at least 60 minutes prior to infusion. Patients will have repeat SPEP + IFE, 24-hour UPEP + IFE and FLC testing every 4 weeks. There will be an optional repeat kidney biopsy 9-12 months following treatment initiation to assess pathologic response in the kidneys. Statistical Methods: The study will be comprised of 20 patients being treated with isatuximab over a span of 24-30 months. Ten patients will be initiated on the therapy for a period of 6 months. Interim analysis will be done after these patients have completed all the treatment cycles. If 4 out of 10 patients show response in form of improved/stable renal function, the study will proceed to include next 10 patients. If >50% of the first group of 10 patients show doubling of creatinine while on therapy, that would be considered as an indication to discontinue the therapy and the study due to drug toxicity. Endpoints: The primary endpoint will be efficacy as measured by renal response and hematologic response. Renal response will be measured by assessing the amount of proteinuria in a 24 hour urine sample. A sustained reduction in proteinuria by 30% from the patient's baseline amount of proteinuria with stable renal function (serum eGFR within 20% of baseline) will be considered a positive renal response. Hematologic response will be quantified per the 2016 International Myeloma Working Group (IMWG) uniform response criteria for multiple myeloma. An important secondary endpoint will be safety and will be analyzed from all patients who receive any study drug. Adverse events will be characterized and graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Other endpoints include time to dialysis and rate of minimal residual disease (MRD) negativity. Disclosures Lentzsch: Caelum Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy; Janssen: Consultancy; Takeda: Consultancy; BMS: Consultancy; Proclara: Consultancy; Abbvie: Consultancy; Clinical Care Options: Speakers Bureau; Sanofi: Consultancy, Research Funding; Multiple Myeloma Research Foundation: Honoraria; International Myeloma Foundation: Honoraria; Karyopharm: Research Funding; Columbia University: Patents & Royalties: 11-1F4mAb as anti-amyloid strategy. Bhutani:Sanofi: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Our trial will be evaluating the efficacy of targeting CD38 on plasma cells with isatuximab in patients with monoclonal gammopathy of renal significance (MGRS). We will evaluate the effects of this drug on 24 hour proteinuria and hematologic response.

scholarly journals Conventional Therapy for Amyloid Light-Chain Amyloidosis

2020 ◽  
Vol 143 (4) ◽  
pp. 365-372
Author(s):  
Paolo Milani ◽  
Giovanni Palladini
Keyword(s):  
Stem Cell ◽  
Plasma Cell ◽  
Light Chain ◽  
Cell Clone ◽  
Alkylating Agents ◽  
Proteasome Inhibitors ◽  
Response Rates ◽  
Al Amyloidosis ◽  
Cell Transplant ◽  
Conventional Chemotherapy

The vast majority of patients with light-chain (AL) amyloidosis are not eligible for stem cell transplant and are treated with conventional chemotherapy. Conventional regimens are based on various combinations of dexamethasone, alkylating agents, proteasome inhibitors, and immunomodulatory drugs. The choice of these regimens requires a careful risk stratification, based on the extent of amyloid organ involvement, comorbidities, and the characteristics of the amyloidogenic plasma cell clone. Most patients are treated upfront with bortezomib and dexamethasone combined with cyclophosphamide or melphalan. Cyclophosphamide does not compromise stem cell mobilization and harvest and is more manageable in renal failure. Melphalan can overcome the effect of t(11;14), which is associated with lower response rates and shorter survival in subjects treated with bortezomib and dexamethasone, or in combination with cyclophosphamide. Lenalidomide and pomalidomide are the mainstay of rescue treatment. They are effective in patients exposed to bortezomib, dexamethasone, and alkylators, but deep hematologic responses are rare. Ixazomib, alone or in combination with lenalidomide, increases the rate of complete responses in relapsed/refractory patients. Conventional chemotherapy regimens will represent the backbone for future combinations, particularly with anti-plasma-cell immunotherapy, that will further improve response rates and outcomes.

scholarly journals Recent Advances in the Diagnosis, Risk Stratification, and Management of Systemic Light-Chain Amyloidosis

2019 ◽  
Vol 141 (2) ◽  
pp. 93-106 ◽  
Author(s):  
Iuliana Vaxman ◽  
Morie Gertz
Keyword(s):  
Plasma Cell ◽  
Light Chain ◽  
Cell Clone ◽  
Proteasome Inhibitors ◽  
Clinical Manifestations ◽  
Al Amyloidosis ◽  
Amyloid Deposits ◽  
Protein Fibrils ◽  
Risk Patients ◽  
Intensive Search

The term amyloidosis refers to a group of disorders in which protein fibrils accumulate in certain organs, disrupt their tissue architecture, and impair the function of the effected organ. The clinical manifestations and prognosis vary widely depending on the specific type of the affected protein. Immunoglobulin light-chain (AL) amyloidosis is the most common form of systemic amyloidosis, characterized by deposition of a misfolded monoclonal light-chain that is secreted from a plasma cell clone. Demonstrating amyloid deposits in a tissue biopsy stained with Congo red is mandatory for the diagnosis. Novel agents (proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, venetoclax) and autologous stem cell transplantation, used for eliminating the underlying plasma cell clone, have improved the outcome for low- and intermediate-risk patients, but the prognosis for high-risk patients is still grave. Randomized studies evaluating antibodies that target the amyloid deposits (PRONTO, VITAL) were recently stopped due to futility and currently there is an intensive search for novel treatment approaches to AL amyloidosis. Early diagnosis is of paramount importance for effective treatment and prognosis, due to the progressive nature of this disease.

Utility of Multiparameter Flow Cytometry Immunophenotypic Studies In Patients with Systemic Light Chain (AL) Amyloidosis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4051-4051
Author(s):  
Bruno Paiva ◽  
María-Belén Vidriales ◽  
Jose J. Perez ◽  
Maria-Consuelo López-Berges ◽  
Ramón García-Sanz ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Flow Cytometry ◽  
Differential Diagnosis ◽  
Plasma Cell ◽  
Light Chain ◽  
Cell Cycle Analysis ◽  
Disease Assessment ◽  
Multiparameter Flow Cytometry ◽  
Al Amyloidosis

Abstract Abstract 4051 Multiparameter flow cytometry (MFC) immunophenotyping has shown to be of value for differential diagnosis and minimal residual disease assessment in multiple myeloma. However, the clinical value of MFC immunophenotyping in other plasma cell disorders (PCD) remains largely unexplored. Systemic light chain (AL) amyloidosis is a rare PCD characterized by the accumulation of monoclonal light chain fragments leading to end-organ damage and short survival. Bone marrow (BM) plasma cell (PC) infiltration in AL is usually low and thus the identification of clonal PC can be often difficult by immunohistochemistry and/or immunofluorescence. In the present study we focused on 34 BM samples sent to our institution with a suspected diagnosis of AL. MFC immunophenotypic studies were performed using the following 4-color combinations of MoAbs (FITC/PE/PerCP-Cy5.5/APC): CD38/CD56/CD19/CD45 (n=34); in addition cy-Kappa/cy-Lambda/CD19/CD38 staining was add to confirm the clonal or polyclonal nature of BMPC in equivocal cases. Ploidy and cell cycle analysis were additionally performed in a subset of cases (n=12/34). From the total 34 cases included in the present study, 28 had a confirmed diagnosis of AL. The remaining 6 cases were finally diagnosed with localized - amyloidoma - (n=2) and familial (n=1) forms of amyloidosis, multiple myeloma-associated amyloid (n=2) and congestive pericarditis (n=1). Interestingly, the presence of clonal PC was detected by MFC in 27 of the 28 (96%) patients with AL; in turn, clonal PC were undetectable in the BM of all cases with localized and familial forms of amyloidosis. The median overall level of PC (M-PC plus N-PC) seen in MFC immunophenotypic analyses of BM samples of the 28 patients with AL was 1.9% (range: 0.1% - 15%), with a significant positive correlation between PC enumerated by MFC and conventional morphology (r=0.5; p=.01). Within the BMPC compartment, the median proportion of clonal PC was of 94% (mean 81% ± 29%); in 6 cases all BMPC were clonal while in the remaining 22 patients residual normal PC persisted (median of normal PC/BMPC 13% ± 31%). The most common aberrant phenotypes were down-regulation of CD19 (92%) and CD45 (83%), followed by overexpression of CD56 (56%) and infra-expression of CD38 (42%). Aneuploidy was only found in 18% of cases, all of them hyperdiploid. Cell cycle analysis showed a median % of S-phase and G2-Mitosis PC of 0.7% and 3.5%, respectively. Concerning patients' outcome, cases with undetectable normal PC (6/28, 21%) had a significantly decreased overall survival (OS) compared to patients with persistent BM normal PC at diagnosis (22/28, 79%) with 3-year OS rates of 0% vs. 59%, respectively (p=.001). In summary, these preliminary data suggests that MFC immunophenotyping investigations may be clinically relevant in patients with suspected amyloidosis for i) differential diagnosis between AL and other forms of amyloidosis and, ii) prognostication of patients with AL according to the presence or absence of baseline persistent normal PC. Disclosures: No relevant conflicts of interest to declare.

Exome Sequencing to Define a Genetic Signature of Plasma Cells in Systemic AL Amyloidosis

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 726-726 ◽  
Author(s):  
Eileen M Boyle ◽  
Brian A Walker ◽  
Dorota Rowczienio ◽  
Christopher P Wardell ◽  
Alexander Murison ◽  
...  
Keyword(s):  
B Cell ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Plasma Cell ◽  
Plasma Cells ◽  
Al Amyloidosis ◽  
Newly Diagnosed ◽  
Mutational Landscape ◽  
Genetic Signature ◽  
Whole Exome

Abstract Introduction: Systemic light chain amyloidosis (AL) is characterized by the deposition of immunoglobulin light chains as amyloid fibrils in different organs, where they form toxic protein aggregates. The underlying disease is a plasma cell disorder, likely a monoclonal gammopathy, but limited data are available on the biology of the plasma cell clone underlying AL and existing studies have concentrated on chromosomal abnormalities. We report the final findings of the first exome sequencing to define the plasma cell signature in AL and compared this to other mature lymphoid malignancies. Methods: Whole exome sequencing was performed on 27 newly diagnosed, histologically proven amyloidosis patients. DNA was extracted from peripheral blood and CD138+ plasma cells and whole exome sequencing was performed using SureSelect (Agilent). In addition to capturing the exome, extra baits were added covering the IGH, IGK, IGL and MYC loci in order to determine the breakpoints associated with translocations in these genes. Tumour and germline DNA were sequenced and data processed to generate copy number, acquired variants and translocation breakpoints in the tumour. Patient demographics: The median age at diagnosis was 69 (range: 41-81) years old. All cases were histologically proven, newly diagnosed AL amyloid. 74% were lambda restricted and 26% kappa with median respective median involved sFLC were 180 mg/L (range: 58.9-986 mg/L) and 730 mg/L (609-3190 mg/L) respectively. The median plasmocytosis was 17.5% (range: 2-90%). 78% of them had evidence of heart involvement, 70% had renal involvement and 33% had liver involvement. Mutation load: The median number of acquired non-synonymous variants per sample was 65 (range 7-285) with 40 (4-251) potentially disease causing variants per sample. Mutational landscape: Although no genes were significantly mutated, the genes closest to significance were NRAS, PIM1, and HIST1H3F. We identified 2 cases with NRAS mutations in the codon 61 (Q61R and Q61H) but no KRAS mutations were seen. Interestingly, there were mutations in some of the significantly mutated genes in myeloma such as EGR1 (Q95R), DIS3 (M505L and D317E) and TRAF3 (splice site). One patient bore a CARD11 (R1077W) mutation, more commonly seen in non-Hodgkin’s lymphoma. Although 22% of our samples had a t(11;14) translocations we did not observe any mutations in CCND1. We identified a t(1;14) (p36;q32) previously described in non-hodgkin lymphoma in one patient. We also identified a Myc translocation in a patient who met the criteria for smouldering myeloma. As previously described in myeloma, both DIS3 mutants occurred in patients with a del(13q). Finally, there was no APOBEC signature in our small samples cohort butwe identified an unspecific mutational signature that was related to age. When comparing the spectrum of mutated genes in both amyloidosis (n=27) and previously sequenced myeloma samples (n=463), we identified 948 genes in common between myeloma and amyloidosis. Four hundred and forty two genes were only mutated in amyloidosis most of them being in housekeeping genes. The clustering of the most frequent and significantly mutated genes in each B-cell malignancy, suggests amyloidosis resembles myeloma and MGUS more than other B-cell malignancies. Discussion: The mutational landscape of amyloidosis resembles myeloma with no disease defining mutations but a variety of mutations occurring in different pathways such as RAS and NF-kB. Two samples had an NRAS mutation, which is a known driver mutation also found in MM. We identified a non-canonical IgH translocation that is a rare event in myeloma. There was little overlap in mutated genes indicating a diverse spectrum of mutations, which is in common with MM. Given the diverse mutational spectrum it will be necessary to study a large cohort to fully understand the genetic complexity of the disease. Conclusion: We conclude that exome sequencing identifies a genetic signature of AL amyloidosis which is similar to other plasma cell disorders in terms of translocations and non-synonymous mutations. Disclosures Walker: Onyx Pharmaceuticals: Consultancy, Honoraria.

scholarly journals In Vitro and inVivo Activity of Melflufen in Amyloidosis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3100-3100 ◽  
Author(s):  
Ken Flanagan ◽  
Muntasir M Majumder ◽  
Romika Kumari ◽  
Juho Miettinen ◽  
Ana Slipicevic ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Cell Lines ◽  
Plasma Cell ◽  
Light Chain ◽  
Research Funding ◽  
Plasma Cells ◽  
Al Amyloidosis ◽  
Advisory Committees

Background: Immunoglobulin light-chain (AL) amyloidosis is a rare disease caused by plasma cell secretion of misfolded light chains that assemble as amyloid fibrils and deposit on vital organs including the heart and kidneys, causing organ dysfunction. Plasma cell directed therapeutics, aimed at preferentially eliminating the clonal population of amyloidogenic cells in bone marrow are expected to reduce production of toxic light chain and alleviate deposition of amyloid thereby restoring healthy organ function. Melphalan flufenamide ethyl ester, melflufen, is a peptidase potentiated alkylating agent with potent toxicity in myeloma cells. Melflufen is highly lipophilic, permitting rapid cellular uptake, and is subsequently enzymatically cleaved by aminopeptidases within cells resulting in augmented intracellular concentrations of toxic molecules, providing a more targeted and localized treatment. Previous data demonstrating multiple myeloma plasma cell sensitivity for melflufen suggests that the drug might be useful to directly eliminate amyloidogenic plasma cells, thereby reducing the amyloid load in patients. Furthermore, the increased intracellular concentrations of melflufen in myeloma cells indicates a potential reduction in systemic toxicity in patients, an important factor in the fragile amyloidosis patient population. To assess potential efficacy in amyloidosis patients and to explore the mechanism of action, we examined effects of melflufen on amyloidogenic plasma cells invitro and invivo. Methods: Cellular toxicity and apoptosis were measured in response to either melflufen or melphalan in multiple malignant human plasma cell lines, including the amyloidosis patient derived light chain secreting ALMC-1 and ALMC-2 cells, as well as primary bone marrow cells from AL amyloidosis patients, using annexin V and live/dead cell staining by multicolor flow cytometry, and measurement of cleaved caspases. Lambda light chain was measured in supernatant by ELISA, and intracellular levels were detected by flow cytometry. To assess efficacy of melflufen in vivo, the light chain secreting human myeloma cell line, JJN3, was transduced with luciferase and adoptively transferred into NSG mice. Cell death in response to melflufen or melphalan was measured by in vivo bioluminescence, and serum light chain was monitored. Results: Melflufen demonstrated increased potency against multiple myeloma cell lines compared to melphalan, inducing malignant plasma cell death at lower doses on established light chain secreting plasma cell lines. While ALMC-1 cells were sensitive to both melphalan and melflufen, the IC50 for melphalan at 960 nM was approximately 3-fold higher than melflufen (334 nM). However, ALMC-2 cells were relatively insensitive to melphalan (12600 nM), but maintained a 100-fold increase in sensitivity to melflufen (121 nM). Furthermore, while 40% of primary CD138+ plasma cells from patients with diagnosed AL amyloidosis responded to melflufen treatment in vitro, only 20% responded to melphalan with consistently superior IC50 values for melflufen (Figure 1). Light chain secreting cell lines and AL amyloidosis patient samples were further analyzed by single cell sequencing. We further examined differential effects on apoptosis and the unfolded protein response in vitro in response to either melflufen or melphalan. This is of particular interest in amyloidosis, where malignant antibody producing plasma cells possess an increased requirement for mechanisms to cope with the amplified load of unfolded protein and associated ER stress. As AL amyloidosis is ultimately a disease mediated by secretion of toxic immunoglobulin, we assessed the effects of melflufen on the production of light chain invitro, measuring a decrease in production of light chain in response to melflufen treatment. Finally, we took advantage of a recently described adoptive transfer mouse model of amyloidosis to assess the efficacy of melflufen and melphalan in eliminating amyloidogenic clones and reducing the levels of toxic serum light chain in vivo. Conclusions: These findings provide evidence that melflufen mediated toxicity, previously described in myeloma cells, extends to amyloidogenic plasma cells and further affects the ability of these cells to produce and secrete toxic light chain. This data supports the rationale for the evaluation of melflufen in patients with AL amyloidosis. Figure 1 Disclosures Flanagan: Oncopeptides AB: Employment. Slipicevic:Oncopeptides AB: Employment. Holstein:Celgene: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; Genentech: Membership on an entity's Board of Directors or advisory committees; Sorrento: Consultancy. Lehmann:Oncopeptides AB: Employment. Nupponen:Oncopeptides AB: Employment. Heckman:Celgene: Research Funding; Novartis: Research Funding; Oncopeptides: Research Funding; Orion Pharma: Research Funding.

scholarly journals Daratumumab in the Treatment of Light-Chain (AL) Amyloidosis

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 545
Author(s):  
Giovanni Palladini ◽  
Paolo Milani ◽  
Fabio Malavasi ◽  
Giampaolo Merlini
Keyword(s):  
Plasma Cell ◽  
Light Chain ◽  
Cell Clone ◽  
Randomized Study ◽  
Standard Of Care ◽  
Phase Iii ◽  
Standards Of Care ◽  
Al Amyloidosis ◽  
Stage Of Development ◽  
Combination Regimens

Systemic light-chain (AL) amyloidosis is caused by a small B cell, most commonly a plasma cell (PC), clone that produces toxic light chains (LC) that cause organ dysfunction and deposits in tissues. Due to the production of amyloidogenic, misfolded LC, AL PCs display peculiar biologic features. The small, indolent plasma cell clone is an ideal target for anti-CD38 immunotherapy. A recent phase III randomized study showed that in newly diagnosed patients, the addition of daratumumab to the standard of care increased the rate and depth of the hematologic response and granted more frequent organ responses. In the relapsed/refractory setting, daratumumab alone or as part of combination regimens gave very promising results. It is likely that daratumumab-based regimens will become new standards of care in AL amyloidosis. Another anti-CD38 monoclonal antibody, isatuximab, is at an earlier stage of development as a treatment for AL amyloidosis. The ability to target CD38 on the amyloid PC offers new powerful tools to treat AL amyloidosis. Future studies should define the preferable agents to combine with daratumumab upfront and in the rescue setting and assess the role of maintenance. In this review, we summarize the rationale for using anti-CD38 antibodies in the treatment of AL amyloidosis.

scholarly journals Calreticulin expression in the clonal plasma cells of patients with systemic light-chain (AL-) amyloidosis is associated with response to high-dose melphalan

Blood ◽  
2008 ◽  
Vol 111 (2) ◽  
pp. 549-557 ◽  
Author(s):  
Ping Zhou ◽  
Julie Teruya-Feldstein ◽  
Ping Lu ◽  
Martin Fleisher ◽  
Adam Olshen ◽  
...  
Keyword(s):  
Plasma Cell ◽  
Light Chain ◽  
Calcium Binding ◽  
Plasma Cells ◽  
Complete Response ◽  
High Dose ◽  
Al Amyloidosis ◽  
Embryonic Fibroblasts ◽  
Knock Out ◽  
High Dose Melphalan

In high doses with stem-cell transplantation, melphalan is an effective but toxic therapy for patients with systemic light-chain (AL-) amyloidosis, a protein deposition and monoclonal plasma cell disease. Melphalan can eliminate the indolent clonal plasma cells that cause the disease, an achievement called a complete response. Such a response is usually associated with extended survival, while no response (a less than 50% reduction) is not. Gene-expression studies and a stringently supervised analysis identified calreticulin as having significantly higher expression in the pretreatment plasma cells of patients with systemic AL-amyloidosis who then had a complete response to high-dose melphalan. Calreticulin is a pleiotropic calcium-binding protein found in the endoplasmic reticulum and the nucleus whose overexpression is associated with increased sensitivity to apoptotic stimuli. Real-time PCR and immunohistochemical staining also showed that expression of calreticulin was higher in the plasma cells of those with a complete response. Furthermore, wild-type murine embryonic fibroblasts were significantly more sensitive to melphalan than calreticulin knock-out murine embryonic fibroblasts. These data have important implications for understanding the activity of melphalan in plasma-cell diseases and support further investigation of calreticulin and its modulation in patients with systemic AL-amyloidosis receiving high-dose melphalan.

scholarly journals Daratumumab Interferes with Flow Cytometric Evaluation of Multiple Myeloma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5630-5630 ◽  
Author(s):  
Sudhir Perincheri ◽  
Richard Torres ◽  
Christopher A Tormey ◽  
Brian R Smith ◽  
Henry M Rinder ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Flow Cytometry ◽  
Cell Population ◽  
Plasma Cell ◽  
Light Chain ◽  
Plasma Cells ◽  
Kappa Light Chain ◽  
Positive Events ◽  
History Of

Abstract The diagnosis of multiple myeloma (MM) requires the demonstration of clonal plasma cells at ≥10% marrow cellularity or a biopsy-proven bony or extra-medullary plasmacytoma, plus one or more myeloma-defining events. Clinical laboratories use multi-parameter flow cytometry (MFC) evaluation of cytoplasmic light chain expression in CD38-bright, CD45-dim or CD138-positive, CD45dim cells to establish plasma cell clonality with a high-degree of sensitivity and specificity. Daratumumab, a humanized IgG1 kappa monoclonal antibody targeting CD38, has been shown to significantly improve outcomes in refractory MM, and daratumumab was granted breakthrough status in 2013. Daratumumab is currently approved for treatment of MM patients who have failed first-line therapies. It has been noted that daratumumab can interfere in blood bank assays for antibody screening, as well as serum protein electrophoresis (SPEP). We describe for the first time daratumumab interference in the assessment of plasma cell neoplasms by MFC; daratumumab interfered with both CD38- and CD138-based gating strategies in three MM patients. Patient A is a 68 year old man with a 10 year history of MM who had failed multiple therapies. He had then been treated with daratumumab for two months, stopping therapy 25 days prior to bone marrow assessment. Patient B is a 53 year old man with a 3 year history MM who had failed numerous treatments. He had been receiving daratumumab monotherapy for two months at the time of his bone marrow studies. On multiple marrow aspirates at times of relapse prior to receiving daratumumab, both patients had demonstrated CD38-bright positive CD45dim/negative plasma cells expressing aberrant CD56, as well as kappa light chain restriction; mature B cells were polyclonal in both. Patient C is a 65 year old man with a four-year history of MM status post autologous stem cell transplantation, who had been receiving carfilzomib and pomalidomide following relapse and continues to have rising lambda light chains and rib pain. He now has abnormal plasma cells in blood worrisome for plasma cell leukemia. Bone marrow aspirates from patients A and B, and blood from patient C demonstrated near absence of CD38-bright events as detected by MFC (Figure 1). Hypothesizing that these results were due to blocking of the CD38 antigen by daratumumab, gating on CD138-positive events was assessed; surprisingly, virtually no CD138-positive events were detected by MFC. All 3 samples demonstrated a CD56-positive CD45dim population; when light chain studies were employed using specific gating on the CD56-positive population, light chain restriction was demonstrated in all patients (Figure 1). Aspirate morphology confirmed numerous abnormal, nucleolated plasma cells (Figure 2A), thus excluding a sampling error. CD138 and CD38 expression was also tested on the marrow biopsy cores from both patients. In contrast to MFC, immunohistochemistry (IHC) showed positive labeling of plasma cells with both CD138 (Figure 2B) and CD38 (Figure 2C). The reason for the labeling discrepancy between MFC and IHC is unknown. The different antibodies in the assays may target different epitopes; alternatively, tissue fixation/decalcification may dissociate the anti-CD38 therapeutic monoclonal from its target. Detection of clonal plasma cell populations is important for assessing response to therapy. Laboratories relying primarily on MFC to assess marrow aspirates without a concomitant biopsy may falsely diagnose remission or significant disease amelioration in daratumumab-treated patients. MFC is generally highly sensitive for monitoring minimal residual disease (MRD) in MM, but daratumumab-treated patients should have their biopsy evaluated to confirm the MRD assessment by MFC. We were able to detect large numbers of plasma cells and also demonstrate clonality in our patients based on an alternative MFC marker, aberrant CD56 expression, an approach that may not be possible in all cases. Figure 1 Flow cytometry showing near-absence of CD38-bright elements in the marrow of patient A (top panels). Gating on CD56-positive cells in the same sample reveals a kappa light chain-restricted plasma cell population (bottom panels). Figure 1. Flow cytometry showing near-absence of CD38-bright elements in the marrow of patient A (top panels). Gating on CD56-positive cells in the same sample reveals a kappa light chain-restricted plasma cell population (bottom panels). Figure 1 The marrow aspirate from Fig. 1 shows abnormal plasma cells (A). Immunohistochemistry on the concomitant biopsy shows the presence of numerous CD138-positive (B) and CD38-positive (C) plasma cells. Figure 1. The marrow aspirate from Fig. 1 shows abnormal plasma cells (A). Immunohistochemistry on the concomitant biopsy shows the presence of numerous CD138-positive (B) and CD38-positive (C) plasma cells. Disclosures No relevant conflicts of interest to declare.

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