Presence Of Clonal Plasma Cells Research Articles

Genomic instability and genetic heterogeneity in aging: insights from clonal hematopoiesis (CHIP), monoclonal gammopathy (MGUS), and monoclonal B-cell lymphocytosis (MBL).

Aging is a multifaceted process characterized by a gradual decline in physiological function and increased susceptibility to a range of chronic diseases. Among the molecular and cellular mechanisms driving aging, genomic instability is a fundamental hallmark, contributing to increased mutation load and genetic heterogeneity within cellular populations. This review explores the role of genomic instability and genetic heterogeneity in aging in the hematopoietic system, with a particular focus on clonal hematopoiesis of indeterminate potential (CHIP), monoclonal gammopathy of undetermined significance (MGUS), and monoclonal B-cell lymphocytosis (MBL) as biomarkers. CHIP involves the clonal expansion of hematopoietic stem cells with somatic mutations. In contrast, MGUS is characterized by the presence of clonal plasma cells producing monoclonal immunoglobulins, while MBL is characterized by clonal proliferation of B cells. These conditions are prevalent in the aging population and serve as measurable indicators of underlying genomic instability. Studying these entities offers valuable insights into the mechanisms by which somatic mutations accumulate and drive clonal evolution in the hematopoietic system, providing a deeper understanding of how aging impacts cellular and tissue homeostasis. In summary, the hematopoietic system serves as a powerful model for investigating the interplay between genomic instability and aging. Incorporating age-related hematological conditions into aging research, alongside other biomarkers such as epigenetic clocks, can enhance the precision and predictive power of biological age assessments. These biomarkers provide a comprehensive view of the aging process, facilitating the early detection of age-related diseases and hopefully enabling personalized healthcare strategies.

Predicting an Underlying Clonal Plasma Cell Population in Light-Chain Monoclonal Gammopathy of Undetermined Significance Using Free Light-Chain Ratio

Introduction: The management of light-chain (LC) monoclonal gammopathy of undetermined significance (MGUS) presents inherent challenges as the key diagnostic factor - abnormal free-light chain (FLC) levels - only indirectly implies the presence of an underlying clonal cell population. Moreover, the lack of M protein, used in current risk-stratification models, necessitates a distinct approach for risk assessment in LC-MGUS. Using next-generation flow cytometry (NGF), we assessed clonal plasma cell presence in bone marrow (BM) samples from individuals with LC monoclonal gammopathies. This approach enabled us to evaluate the predictive value of FLC ratio for an underlying clonal plasma cell population in LC-MGUS and its prognostic implications. Aim: To evaluate the association between FLC ratio and the presence of clonal plasma cells in the BM of individuals with LC monoclonal gammopathies as well as the risk of progression. Methods: The study is a part of the Iceland Screens, Treats, or Prevents Multiple Myeloma (iStopMM) study, a population-based screening study for multiple myeloma (MM) precursors and randomized trial of follow-up strategies. We included screened individuals with an abnormal FLC ratio (<0.26 or >1.65) and elevated involved LC (kappa ≥19.4 mg/L or lambda ≥26.3 mg/L) (Freelite, The Binding Site), with no detected M protein. Those with previously known MM or related disorders were excluded. NGF was used to determine clonal plasma cell presence in BM samples. Logistic regression was used to assess the relationship between FLC ratio (used as involved/uninvolved ratio throughout the study) and clonal plasma cell presence. Receiver operating characteristic (ROC) curve analysis was used to assess the predictive ability of FLC ratio for clonal plasma cell presence in LC-MGUS and to determine an optimal cutoff value. Kaplan-Meier analysis was used to assess time to progression to more advanced plasma cell disorder for LC-MGUS, stratified by the FLC ratio cutoff. A linear mixed-effects model was used to evaluate the change in FLC ratio (expressed as fold change relative to the screening sample) over time for those with FLC ratio below the cutoff at screening. Results: After screening 75,422 individuals, 1,965 with LC disease were included, with median age of 71 years (range of 42-100 years), and a median FLC ratio of 1.85. Most (95.4%) had involved FLC of type kappa. Clonal plasma cells were identified by NGF in 8/21 (38.1%) LC-MGUS, and all LC-smoldering MM (SMM) (n=21) and LC-MM (n=7) cases. A significant prediction of clonal plasma cell presence was found for FLC ratio (OR=6.47; p=0.012; n=49), supported by ROC curve analysis for LC-MGUS (AUC=0.94; n=21), identifying FLC ratio of 3.15 as optimal cutoff (92% sensitivity, 100% specificity). Of the 254 individuals randomized to active follow-up within the iStopMM study, baseline diagnosis distribution was 223 (87.8%) LC-MGUS, 22 (8.7%) LC-SMM, 7 (2.8%) LC-MM, 1 (0.4%) solitary plasmacytoma, and 1 (0.4%) chronic lymphocytic leukemia. Among these, 123 (representing 88% of the screened study cohort) had FLC ratio <3.15 at screening, thereof 122 (99.2%) with LC-MGUS and 1 (0.8%) with solitary plasmacytoma. No disease progression was observed for individuals with FLC ratio <3.15 (n=100) over a median follow-up of 46 months. Conversely, disease progression occurred in 13/97 (13.4%) LC-MGUS with ≥3.15 FLC ratio (9 to SMM, 3 to MM, and 1 to smoldering Waldenströms macroglobulinemia) during median follow-up of 42 months (p=0.00018 vs FLC ratio <3.15) (Figure). The linear mixed-effects model of 454 repeated FLC from 128 individuals with <3.15 FLC ratio at screening did not indicate significant change in FLC ratio over a median follow-up of 48 months. Conclusions: In this study, we utilized NGF to confirm an underlying clonal plasma cell population in BM of individuals with LC-MGUS and evaluate its association with involved/uninvolved FLC ratio. Clonal plasma cells were detected in a minority of LC-MGUS (38.1%), for which FLC ratio was found to be highly predictive. An FLC ratio cutoff of 3.15 optimally discriminated based on clonal plasma cell presence, and we found no evidence of progressive disease in LC-MGUS below this cutoff during follow-up. Altogether, the more stringent FLC ratio cutoff can assist in determining the likelihood of an underlying clonal plasma cell population in LC-MGUS and may, as such, help to guide the management of LC-MGUS.

Association of Myeloma in Patients of Chronic Kidney Disease; A Single Centered Study

Objective: To evaluate the frequency along with socio-demographic factors and clinical features of myeloma in patients with chronic kidney disease (CKD) presenting at a tertiary care hospital in Karachi, Pakistan. Study design and setting: It was a cross-sectional study conducted at the Department of Nephrology and Hematology, Liaquat National Hospital, Karachi, Pakistan from Jan 2022 to Jul 2022. Methodology: Patients of age>18 years of either gender having chronic kidney disease were included in the study. Detailed data regarding socio-demographic factors, clinical features and presence of multiple myeloma was obtained. Myeloma was diagnosed in the patients using WHO criteria i.e. presence of M-protein in urine or serum, presence of clonal plasma cells in bone marrow, and related tissue or organ failure. Data was entered and analyzed using SPSS version 25. Results: The median age of the patients with chronic kidney disease was 54 years and most of them were males (63%). Myeloma was detected in only 14 patients with CKD. The proportion of myeloma was similar across chronic kidney disease stages, and statistically there was no significant association between chronic kidney disease stages and myeloma with pvalue=0.08. There were no differences in hemoglobin, serum calcium, serum albumin, serum total protein, albumin/globulin (A/G) ratio, ESR, comorbid in patients with and without myeloma (p>0.05). Conclusion: The frequency of myeloma among patients with chronic kidney disease was low.

B-179 Development of a Reflex Mass Spectrometric Workflow for Confirmation of IgE and IgD Specificity Paraproteins Utilising the EXENT® Platform

Abstract Background The EXENT® (GAM) assay is a MALDI-TOF (Matrix Assisted Laser Desorption Ionisation Time of Flight) mass spectrometry-based solution which utilises IgG, IgA, IgM, total kappa and total lambda specific paramagnetic beads, which could be used in the investigation of monoclonal proteins in multiple myeloma and other plasma cell disorders (in development by The Binding Site (TBS), part of Thermo Fisher Scientific). Rare cases of IgD and IgE myelomas will be partially typed with the current iteration of the EXENT (GAM) assay. We present here a workflow to confirm the heavy chain specificity of such paraproteins as IgD or IgE using reflex LC-MS analysis of EXENT eluates. Methods Samples known to contain IgD (2) or IgE (3) paraproteins were provided from either routine workload at the immunology laboratory at Birmingham Heartlands Hospital, UK or an internal library of historical myeloma samples. Capillary zone electrophoresis (CZE) and immunofixation (IFE) were performed on Capillarys2™ and Hydrasys2 Scan™ platforms, respectively (Sebia, France). Serum free light chain (sFLC) measurement was performed using Freelite® reagents (The Binding Site, UK) on a Cobas c501 turbidimeter (Roche, Switzerland). Samples were prepared via EXENT (GAM) assay, by separately incubating diluted serum with antisera specific for IgG, IgA, IgM, total kappa and total lambda conjugated to paramagnetic beads. After washes, purified immunoglobulins were treated to reduce and elute the light chain component. Samples were mixed with matrix, spotted onto a MALDI target plate and acquired by MALDI-TOF MS. Once light-chain specificity of the suspected IgD or IgE paraprotein was determined, repeat immuno-precipitation with the same light-chain bead was carried out. Eluted samples were neutralised, transferred to fresh tubes, reduced, alkylated and digested with trypsin for 3 h. After acidification digested samples were analysed by C18 reverse phase UPLC on a BioAccord LC-MS system (Waters, UK). Data was then screened against a database of known immunoglobulin heavy chain peptides to assess the presence of heavy chain peptides specific for each immunoglobulin isotype. Results In each sample tested, the EXENT solution identified at least one monoclonal light chain that was only seen in the total kappa or total lambda immunoprecipitations with no corresponding monoclonal peak(s) at the same mass(es) in the IgG, IgA or IgM specificities. This finding would be consistent with the presence of clonal plasma cells producing either monoclonal free light chains only, or IgD and IgE paraproteins. Subsequent LC-MS and LC-MSe (tandem MS) analysis of reduced, alkylated and tryptically digested eluates corresponding to these suspected IgD and IgE samples produced high quality peptide sequencing data. The data identified multiple IgD or IgE specific peptides in each sample and showed between 40% and 66% sequence coverage for IgD or IgE heavy-chain constant regions. Thus, confirming the presence of IgD or IgE in these samples which had been partially typed by the EXENT solution. Conclusion This data demonstrates that the EXENT (GAM) assay could potentially aid in detection of IgD and IgE paraproteins when combined with LC-MS proteomic techniques, as it allows efficient and facile confirmation of these rare heavy chain isotypes.

Impact of clonal plasma cells in autografts on outcomes in high-risk multiple myeloma patients

Most patients with multiple myeloma (MM) undergoing autologous hematopoietic stem cell transplantation (autoHCT) eventually relapse, perhaps due to the presence of clonal plasma cells (CPC) in the autograft. We conducted a retrospective analysis to evaluate the impact of CPC in the autograft on the outcomes of high-risk chromosomal abnormalities (HRMM) patients undergoing autoHCT between 2008 and 2018. Patients were divided into CPC+ or CPC− in the autograft by next-generation flow cytometry (NGF). There were 75 CPC + autografts (18%) and 341 CPC− (82%). The CPC + group was less likely to achieve MRD-negative complete remission post-transplant (11% vs. 42%; p < 0.001). Median progression free survival (PFS) and overall survival (OS) were (12.8 vs. 32.1 months) and (36.4 vs. 81.2 months) in the CPC + and CPC− groups, respectively (both p < 0.001). Also in the subset of patients with MRD-negative ≥VGPR prior to autoHCT, those with CPC + autografts had inferior PFS (HR 4.21, p = 0.006) and OS (HR 7.04, p = 0.002) compared to CPC-. In multivariable analysis, the degree of CPC positivity in the autograft was independently predictive of worse PFS (HR 1.50, p = 0.001) and OS (HR 1.37, p = 0.001). In conclusion, both the presence and degree of CPC in the autograft were highly predictive of inferior PFS and OS.

Impact of Presence and Amount of Clonal Plasma Cells in Autografts Affect Outcomes in High-Risk Multiple Myeloma Patients Undergoing Autologous Hematopoietic Stem Cell Transplant

Introduction: Autologous hematopoietic stem cell transplantation (autoHCT) is considered standard of care for patients with multiple myeloma (MM). However, most patients eventually relapse, perhaps due to the presence of clonal plasma cells (CPC) in the autograft. The significance of CPC in the autograft has not been clearly established. MM patients with high-risk chromosomal abnormalities (HRMM) by florescent in situ hybridization (FISH) have worse outcomes compared to patients with standard-risk disease. We conducted a single center retrospective analysis to evaluate the impact of CPC in the autograft on the outcomes of patients with HRMM undergoing an autoHCT at our institution. Methods: Eligible patients had HRMM, received an autoHCT between 2008 and 2018 at our institution, and had 8-color next-generation flow cytometry (NGF) performed on the collected apheresis product for CPC. HRMM was defined as having del17p, t(4;14), t(14;16) and 1q21 gain or amplification by FISH. Patients were divided into two groups: CPC+ or CPC- in the autograft by NGF. Since not all collected autograft products are infused at autoHCT, and some bags may be CPC+ or CPC- for the same patient, we also evaluated the impact of infusion of CPC+ autograft products on patient outcomes. Minimal residual disease (MRD) status on the bone marrow biopsy was evaluated using 8-color next generation flow cytometry with sensitivity of 1/10-5 cells. Results: We analyzed the autograft products of 416 patients: 75 CPC+ (18%) and 341 CPC- (82%). 57% patients were male, and median age at autoHCT was 62 (range 32-83) years. Fewer patients in the CPC+ group received the VRD regimen as induction prior to transplant compared to the CPC- group (25% vs. 44%, p=0.003) and fewer achieved ≥VGPR after induction compared to the CPC- group (32% vs. 62%, p<0.001). Patient and clinical characteristics are presented in Table 1. Median follow up for the whole cohort was 35.7 (range 0.3-139.5) months. 100-day and best post-autoHCT CR rates in the CPC+ and CPC- groups were 8% vs. 19% (p<0.001), and 33% vs. 54% (p<0.001), respectively. The CPC+ group was also less likely to achieve MRD-negative CR post-transplant (11% vs. 42%; p<0.001). Median PFS in the CPC+ vs. CPC- group was 12.8 vs. 32.1 months (p<0.001), and median OS was 36.4 vs. 81.2 months (p<0.001). The degree of autograft CPC involvement was inversely associated with post-transplant day 100 response: mean maximal autograft CPC level was 0.02% (SD 0.02) for patients who achieved ≥VGPR vs. 1.04% (SD 2.59) for those who achieved ≤PR at day 100 post-transplant. Similarly, degree of autograft CPC level was inversely associated with best post-transplant response: mean maximal autograft CPC level was 0.06% (SD 0.16) for patients who achieved ≥VGPR vs. vs. 1.55% (SD 3.17) for those who achieved ≤PR. In patients achieving ≥VGPR prior to autoHCT, those with CPC+ autograft had inferior PFS (hazard ratio (HR) [95% CI]: 3.38 [2.05-5.58], p<0.001; Figure 1C) and OS (HR 2.29 [1.20-4.40], p=0.013; Figure 1D) compared to the CPC- group. Also in patients who achieved MRD- negative CR or VGPR prior to autoHCT, those with CPC+ autograft had inferior PFS (HR 4.35 [1.87-10.16], p<0.001) and OS (HR 6.14 [2.10-17.96], p<0.001) compared to the CPC- group. In a multivariable analysis (MVA), the degree of CPC positivity in the autograft was independently predictive of worse PFS (HR 1.50 [1.12-1.99]; p=0.006) and OS (HR 1.35 [1.08-1.67]; p=0.007). The MVA also showed that infusion of CPC+ autograft products was predictive of worse PFS (HR 2.78 [1.85-4.15]; p<0.001) with a trend towards worse OS (HR 1.66 [0.99-2.78]; p=0.054). Conclusions: Our study shows a major impact of CPC in the autograft on post-autoHCT outcomes in HRMM. Both the presence and degree of CPC in the autograft were highly predictive of inferior PFS and OS, even in patients who had achieved ≥VGPR and MRD-negative CR/VGPR prior to autoHCT. Novel strategies for ex-vivo purging of CPC could improve patient outcomes. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

The NSG-hIL6 Mouse As a Novel Murine Patient Derived Xenograft Model of Plasma Cell Dyscrasias for Study of Disease Biology and Therapeutic Development

Background Plasma cell dyscrasias include pre-malignant and malignant conditions spanning the spectrum from monoclonal gammopathy of undetermined significance (MGUS) to smoldering multiple myeloma (SMM) to active multiple myeloma (aMM) and include the disorders AL amyloidosis and plasma cell leukemia (PCL). Though the last 2 decades has yielded effective therapies against these disorders, there remain no reliably curative treatments, and complications due to multiple myeloma are most often the cause of death. A major reason for the lack of curative therapies is the dearth of relevant research models in which to study these diseases and test new drug candidates. Cell lines that do not reflect the biology of mainstream myeloma are currently the mainstay of disease modeling. Plasma cells do not survive well outside the bone marrow and to this point, little success has been made using primary tumors from patients to model disease. Thus, there is a significant need for more relevant models to build the next, hopefully curative, generation of therapeutics for these diseases. Research Significance We present a novel immunodeficient murine model able to engraft plasma cell dyscrasias from primary patient tumors and the ability to study basic biology and test efficacy of cellular therapies, representing a significant advance in this field. Methods The NSG-h(IL6) mouse, developed by Dr. Shultz, builds on the background NSG mouse that lacks adaptive immunity and has limited innate immunity. It expresses a BAC with a piece of human chromosome 7, containing the human IL-6 gene and all associated local promoter and enhancer elements. With the expertise of the stem cell and xenograft core facility (SCXC), mice were preconditioned with busulfan, and 1e6 mononuclear cells (MNCs) isolated from human myeloma patient marrow aspirate were injected into the murine femur. Blood and urine were sampled every 4-5 weeks and analyzed for the presence of human antibodies by ELISA. Deceased mice were sent for histology and their spleens and marrow analyzed for the presence of clonal plasma cells by flow cytometry. Serum protein electrophoresis (SPEP) and complete blood counts (CBC) were noted as hallmarks of disease. Samples from patients with MGUS, SMM, aMM (both newly diagnosed and relapsed/refractory), PCL and AL amyloidosis were engrafted into mice as above. Mice were treated with untraduced T-cells (UTD) or BCMA-directed CARTs 10 weeks after engraftment of active myeloma and blood was assayed for level of immunoglobulins to follow response. Results Analysis of murine serum and urine by ELISA revealed the presence of rising titers of human antibodies in all engrafted mice and the presence of an M-spike on SPEP. NSG-hIL6 mice conditioned with busulfan showed greater engraftment than non-IL6 containing mice and non-conditioned mice (7 vs 2 vs 0, p<0.005). Light chain specific ELISA showed a clear predominance of one light chain, congruent with the patient sample that was engrafted. Flow cytometric analysis of engrafted murine bone marrow showed the presence of light chain restricted plasma cells. Histology showed the presence of plasma cells in the marrow, spleen and liver of engrafted animals with IHC positivity for specific light chain and CD138. CBC showed pancytopenia (p<0.005) with anemia being most significant in engrafted vs. unengrafted animals. All fresh samples and nearly all frozen samples of MGUS, SMM, aMM, PCL and AL amyloidosis were able to be engrafted at high rates (>50% of mice). Mice injected with column separated CD138+ cells alone showed no engraftment vs. mice injected with total MNCs from the marrow of the same myeloma (3 vs 0, p<0.005 ). BCMA directed CARTs significantly decreased circulating antibody compared to UTD controls (p<0.005). Conclusion Using the NSG-hIL6 mouse, busulfan conditioning and intrafemur injections, we have been able to engraft all the major plasma cell dyscrasias as denoted by the presence of monoclonal human antibody in these mice and presence of light chain restricted plasma cells congruent with the patient's paraprotein. We have preliminarily shown that the ability to engraft disease is dependent on human supporting cells. Additionally, treatment with BCMA directed CARTs is showing a response. This simple model will allow for further preclinical testing of new agents against multiple myeloma and associated plasma cell neoplasms and allow for study of basic biology of these diseases. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Assessment of Treatment Response By Ife, Next Generation Flow Cytometry and Mass Spectrometry Coupled with Liquid Chromatography in the GEM2012MENOS65 Clinical Trial

Assessment of Treatment Response By Ife, Next Generation Flow Cytometry and Mass Spectrometry Coupled with Liquid Chromatography in the GEM2012MENOS65 Clinical Trial

Role of the bone marrow microenvironment in tumor transformation of plasma cell dyscrasias

Despite significant progress in the understanding of the pathogenesis of paraproteinemic hemoblastoses, these diseases remain incurable. In their development, they go through the stage of paraproteinemias, benign diseases, characterized by the detection of monoclonal paraprotein in the blood serum and / or urine, presence of clonal plasma cells in the bone marrow or in extramedullary tissues. It remains unclear why some paraproteinemias progress to multiple myeloma or other lymphoid tumors and how malignant progression occurs. An important role in the progression is played by molecular and genetic mechanisms, cytokines. Nevertheless, little is known about how the bone marrow microenvironment influences disease progression. In this review, we made an attempt to summarize the most significant biological, clinical characteristics on the course of paraproteinemias and the role of changes in the bone marrow microenvironment that contribute to malignant transformation.

CS1-specific single-domain antibodies labeled with Actinium-225 prolong survival and increase CD8+ T cells and PD-L1 expression in Multiple Myeloma

ABSTRACT Multiple myeloma (MM) is a hematological malignancy characterized by the presence of clonal plasma cells in the bone marrow niche. Despite significant therapeutic advances, MM remains incurable for the majority of patients. Targeted radionuclide therapy (TRNT) has emerged as a promising treatment option to eradicate residual cancer cells. In this study, we developed and characterized single-domain antibodies (sdAbs) against the MM-antigen CS1 and evaluated its therapeutic potential in MM using TRNT. We first validated CS1 as potential target for TRNT. CS1 is expressed in normal and malignant plasma cells in different disease stages including progression and relapse. It is expressed in dormant as well as proliferating MM cells, while low expression could be observed in environmental cells. Biodistribution studies demonstrated the specific uptake of anti-CS1 sdAbs in tissues of 5TMM cell infiltration including bone, spleen and liver. TRNT using anti-CS1 sdAbs labeled with actinium-225 significantly prolonged survival of syngeneic, immunocompetent 5T33MM mice. In addition, we observed an increase in CD8+ T-cells and more overall PD-L1 expression on immune and non-immune cells, implying an interferon gamma signature using actinium-225 labeled CS1-directed sdAbs. In this proof-of-principle study, we highlight, for the first time, the therapeutic potential and immunomodulating effects of anti-CS1 radionuclide therapy to target residual MM cells.

MM-252: Aberrant Plasma Cells in the Apheresis Product as a Prognostic Factor for Minimal Residual Disease Negativity After Transplant in Newly Diagnosed Myeloma Patients

Context: Autologous stem cell transplantation (ASCT) is the standard frontline therapy for newly diagnosed multiple myeloma (MM) eligible patients. “Contamination” of leukapheresis products with aberrant plasma cells (PCs) has been considered as a possible predictive factor for response and outcome. Objective: To evaluate the frequency and clinical value of clonal PCs remaining in leukapheresis products using next generation flow cytometry (NGFC), which is able to detect aberrant clonal PCs at levels reaching 10−6. Design: Prospective study. Setting: A referral center in Athens, Greece. Patients: MM patients after four cycles of induction therapy (VCD or VRD) followed by ASCT in the Department of Clinical Therapeutics, University of Athens, Greece. Interventions: Ninety-eight patients with newly diagnosed multiple myeloma were assessed for the presence of clonal PCs with the 8-color NGFC protocol suggested by EuroFlow. Eight to ten million cells were examined; the median sensitivity of the test was 2–4 × 10−6 per sample. All patients received high-dose melphalan and ASCT. Using the same NGFC protocol, 53 patients who achieved complete response (CR) post-ASCT, based on the IMWG criteria, were also examined for the presence of minimal residual disease (MRD). Main outcome measures: Aberrant PCs in leukapheresis products. Results: This analysis revealed 58 (59%) “uncontaminated” (con-) and 40 (41%) “contaminated” (con+) leukapheresis products. The majority of con+ cases had very low numbers of aberrant plasma cells detected; 18 (45%) at the level of 10−615 (38%) at the level of 10−4 and 7 (18%) at levels ≥10−3. On day 100 post-ASCT, MRD evaluation was performed on 33 con- and 20 con+ patients, who had achieved CR. MRD positivity was found in 11 out of 53 cases (20.8%). Only 3 out of 33 (9.1%) con- patients were found MRD+, all of which at very low levels ( Conclusions: Using NGFC, we were able to detect aberrant plasma cells in 40% of apheresis products at the level of 10−6. The presence of aberrant plasma cells in the apheresis products correlates with higher probability for MRD+ after ASCT, whereas their absence predicts MRD negativity.

Autologous stem cell transplantation (ASCT) outcome for multiple myeloma in a tertiary referral centre in Malaysia.

Multiple Myeloma (MM) is characterized by the presence of clonal plasma cells. These often result in complications including bone destruction, hypercalcemia, renal insufficiency, and anaemia. Induction with a triplet or quadruplet regimen followed by autologous stem cell transplantation (ASCT) has been the standard of care for transplant eligible patients to achieve durable remission. This is a retrospective analytical study to determine the outcome of Multiple Myeloma patients who underwent ASCT in Ampang Hospital. We included a 5-year cohort of patients transplanted from 1st July 2014 to 30th June 2019. Data were obtained through electronic medical records. Prognostic factors for progression-free survival (PFS) and overall survival (OS) were analyzed using simple and multiple Cox proportional hazard regression analysis. All analyses were done using software R version 3.6.2 with validated statistical packages. 139 patients were analyzed. The median age at transplant was 56 years old and 56.1% are males (n＝78). The most common subtype is IgG Kappa (n＝67, 48.2%). Only 93 patients in which the International Staging System (ISS) could be determined, and among them, 33.3% of patients (n＝31) have advanced stage Ⅲ disease. The most common induction received before ASCT was a bortezomib based regimen and/or an immunomodulatory (IMiD) based regimen. 63.3% of patients achieved at least a very good partial response (VGPR) before ASCT. Most patients received myeloablative conditioning (MAC) (n＝119, 85.6%). The mean cell dose is 3.68×106/kg. The median time to engraftment was 11 days for both platelet and absolute neutrophil count (ANC). With the median follow-up of 17.3 (range, 6.2-33.4) months, the median OS and PFS were not reached. The 1-year and 2-year PFS were 75% (95% CI 66-82%) and 52% (95% CI 42-62%), respectively. The 1-year and 2-year OS were 82% (95% CI 74-88%) and 70% (95% CI 60-78%), respectively. 6 patients (4.3%) had transplant-related mortality (TRM). IgA subtype was found to adversely affect PFS. Maintenance therapy and the absence of renal impairment was associated with better PFS and OS. Our study found that ASCT following induction treatment is safe and beneficial to achieve a deeper remission status. In our study, the addition of maintenance therapy is associated with an improved outcome in PFS and OS.

Impact of Osseous and Non-Osseous Extramedullary Disease in Multiple Myeloma: Clinical Characteristics and Outcomes in a Latin American Population

Introduction Extramedullary myeloma (EMM) is the synchronous presence of clonal plasma cells (CPC) in both bone marrow and distant sites. Its frequency is reported among 6-20% of multiple myeloma (MM) patients and can manifest as osseous plasmacytoma (OP) or non-osseous plasmacytoma (NOP). Previous reports outline a more aggressive clinical behavior in patients presenting with EMM and in Latin American population. However, there is scarce data regarding EMM in Latin American patients. The aim of this study was to describe the clinical characteristics and impact of EMM on survival outcomes in all patients diagnosed and followed at our institution. Methods Retrospective single-center study that included &gt;18-year-old MM patients, as defined by the IMWG criteria. EMM was defined as the presence of CPC in any osseous or non-osseous tissue outside of the bone marrow or as the demonstration of a synchronous tumor at a non-accessible site by imaging methods. Results A total of 199 patients were included. Demographic and clinical characteristics are shown in Figure 1. Sixty-three patients had EMM (31.8%), of which 45 cases (71.4%) presented at diagnosis and 18 (28.6%) at progression. Forty-eight cases (76.2%) were diagnosed by biopsy and 15 (23.8%) by imaging studies. Fifty-four percent (n=34) of the cases presented as OP and 46% (n=29) as NOP. Most-frequently involved sites included the spine and chest wall in OP and abdomen and thorax in NOP (Figure 2). EMM was associated with lower comorbidity rates and higher incidence of renal failure. Mean progression-free survival (PFS) and overall survival (OS) were 22.9 and 43.7 months, respectively. EMM at any time of disease course resulted on lower PFS and OS (15.7 months vs. 26.2 months, p=0.04; 32.1 months vs. 65.1 months, p=0.03). The presence of NOP was related with lower OS (28.4 months vs. 59.2 months, p&lt;0.01). A higher ECOG (HR 1.62; 95%CI 1.04-2.53; p=0.034), less profound responses to treatment (HR 0.30; 95%CI 0.21-0.40; p&lt;0.001), and the presence of EMM (HR 1.53; 95%CI 1.04-2.25; p=0.032) were associated with worse PFS; while both high ISS (HR 1.54; 95%CI 1.0-2.2; p=0.018) and less profound responses (HR 0.52; 95%CI 0.37-0.73; p&lt;0.001) resulted in worse OS in multivariate analysis. Other factors affecting PFS and OS are shown in Figure 3. Conclusion We observed higher rates of EMM in our cohort when compared with the reported literature. The presence of EMM was associated with poor prognosis as evidenced by lower PFS and OS. When comparing OP vs. NOP EMM, NOP conferred an increased risk of early mortality. Results suggest that more aggressive disease biology, higher tumor burden, and/or delayed referral for diagnosis and therapy in our population of MM patients contribute to these unfavorable outcomes. It is imperative that our knowledge on high-risk MM groups, including EMM, in minorities is expanded. Latin American countries are urged to work together in collaborative research to confirm these results in order to properly identify patients who may benefit from more intensive treatment that might result in the improvement of long-term outcomes. Disclosures Martinez-Banos: Celgene, Amgen: Other: Advisory Board.

Research progress on treatment of extramedullary myeloma

Extramedullary myeloma (EMM) refers to the presence of clonal plasma cells outside the bone marrow in a patient with multiple myeloma (MM). The development of novel agents and hematopoietic stem cell transplantation (HSCT) significantly extend the survival of patients with MM, but none of the current treatments can completely overcome the adverse prognosis of EMM, and the prognosis of EMM is still poor. It is important to understand the current status of EMM treatments and explore new therapies to improve the prognosis of EMM. This article summarizes the recent advances in the treatment of EMM, including chemotherapy, HSCT, cellular immunotherapy and molecular targeted therapy. Key words: Multiple myeloma; Antineoplastic combined chemotherapy protocols; Hematopoietic stem cell transplantation; Molecular targeted therapy; Extramedullary myeloma; Chimeric antigen receptor-based immunotherapy

The Utility of Non-Invasive Liquid Biopsy for Mutational Analysis and Minimal Residual Disease Assessment in Extramedullary Multiple Myeloma

Liquid biopsy is a promising technique for tumor genetic profiling and evaluating disease progression. Recent advances in circulating tumor DNA (ctDNA) research highlight its utility in solid tumors and hematological diseases. Extramedullary multiple myeloma (EMM) is an advanced type of multiple myeloma, defined by the presence of clonal plasma cells outside of the bone marrow. The potential of ctDNA to reveal the holistic genomic landscape of EMM is of great interest. Moreover, the mutational concordance between ctDNA and extramedullary plasmacytoma biopsies requires further investigation. In this study, using time-matched extramedullary plasmacytoma biopsies, bone marrow aspirates, and plasma samples from eight EMM patients, we conducted deep sequencing targeting the coding regions of 22 multiple myeloma-related genes. Sequencing results were further verified using droplet digital PCR. Gene mutations in mitogen-activated protein kinase pathways were identified in all 8 tissue biopsies and 7/8 (87.5%) time-matched plasma samples. The ctDNA to tissue biopsy concordance and bone marrow aspirate to tissue biopsy concordance were 0.873 (P = 8.66e−7) and 0.621 (P = 0.109), respectively. In conclusion, our results suggest that ctDNA can be a reliable surrogate for extramedullary plasmacytoma biopsy to characterize the genomic landscape and track disease progression, particularly when extramedullary plasmacytomas are inaccessible. Funding Statement: This work was supported in part by the National Science Foundation for Young Scientists of China (No. 81700160), National Natural Science Foundation of China (General Program, No. 81873452), National Natural Science Foundation of China (Key Program, No. 81630006). Declaration of Interests: The authors stated: No relevant conflicts of interest to declare. Ethics Approval Statement: This study was approved by Ethics Committee of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. The approval file number is TJ-IRB20180813.

PB2017 SEQUENTIAL IMPROVEMENTS IN THE OUTCOME OF INTENSIVE INDUCTION CHEMOIMMUNOTHERAPY FOLLOWED BY AUTOLOGOUS STEM CELL TRANSPLANTATION IN PATIENTS WITH UNTREATED WALDENSTROM MACROGLOBULINEMIA.

Background:Waldenstrom Macroglobulinemia (WM) is still considered an incurable IgM‐secreting lymphoplasmacytic lymphoma. The role of intensive induction chemoimmunotherapy followed by autologous stem cell transplantation (ASCT) in the management of patients with WM has not been established.Aims:To study the effectiveness of intensive induction chemoimmunotherapy and its combination with ibrutinib followed by ASCT in patients with untreated WM.Methods:A total of 8 treatment naive patients with WM were enrolled in our study between March 2017 and February 2019 years. Median age was 55.5 years (range 34‐62 years) and 6 (75%) were men. Three patients were treated with 4 cycles of alternating of R‐EPOCH (rituximab, doxorubicin, etoposide, vincristine, cyclophosphamide, prednisolone) in conventional doses and R‐BAC (rituximab, bendamustin, cytarabine) in conventional doses – group №1. Five patients were treated with 4 cycles of alternating of R‐EPOCH + ibrutinib 420 mg daily and R‐BAC + ibrutinib 420 mg daily – group №2. Response was assessed using modified IWWM‐6 criteria.Results:According to IPSSWM – 1,4 and 3 patients, were considered as being at low, intermediate, and high risk respectively. Indications for treatment included hyperviscosity ‐ related symptoms in 8 (100%) patients, anemia in 8 (100%), lymphadenopathy and splenomegaly in 7 (87.5%), constitutional symptoms in 6 (75%) and thrombocytopenia 2 (25%). At baseline, median serum total protein was 115 g/l (range 101‐130 g/l), median serum IgM monoclonal protein was 53 g/l (range 39‐74 g/l), median hemoglobin was 7.8 g/dl (range 5.6‐10.5 g/dl), median β‐2‐microglobulin was 4.32 mg/l (2.8‐9.3 mg/l). High serum LDH activity was in 3 (37.5%) patients, albumin less than 30 g/l was in 3 (37.5%) patients. In 6 (75%) patients the MYD88L265P mutation was detected and CXCR4 mutation was not detected in any patients. Deletion of 17p was identified in one patient but mutation of the TP53 gene determined using by Sanger sequencing of the coding region (exons 1(2)‐11) was not identified in any patients. All evaluable patients have completed 4 cycles of induction therapy. Partial response (PR) was attained in 8 (100%). Median hemoglobin increased to 12.7 g/dl (range 12.1‐ 13.7 g/dl) and regression of all baseline symptoms occurred in all cases. Two patients in group №1 and 3 in group №2 subsequently underwent ASCT, the preparative regimen was CEAM (lomustine, etoposide, cytarabine, melphalan). Very good partial response was achieved in one patient after ASCT and in 4 patients serum IgM monoclonal protein continued to decline (tab.). Median observation without progression from the end of therapy is 8 (range 1‐17) months and we continue our research.Summary/Conclusion:The combination of intensive immunochemotherapy with ibrutinib leads to rapid and deep decline of serum IgM monoclonal protein and regression of baseline symptoms of WM. Applying of ibrutinib as part of chemoimmunotherapy for a limited period of time results in a lower financial burden compared to its long‐term use. ASCT as part of first line therapy leads to improve in the outcomes and may be a safe, feasible, and reasonable therapeutic option for young WM patients. Perhaps, residual serum IgM monoclonal protein is due to the presence of clonal plasma cells in the bone marrow after treatment and is considered as residual disease. Applying targeted therapy might possibly to eliminate this pathological clone.image

PB2140 IMPACT OF EXTRAMEDULLARY DISEASE IN THE OUTCOMES OF MEXICAN PATIENTS WITH MULTIPLE MYELOMA

Background:Extramedullary myeloma (EMM) is the synchronous presence of clonal plasma cells (CPC) at bone marrow and distant sites. Its frequency is reported among 6‐20% of multiple myeloma (MM) patients and manifest as bone‐dependent plasmocitoma (BP) or tissue‐dependent plasmocitoma (TP). Previous reports state a more aggressive clinical course, whether at diagnosis or relapse. There is no data regarding the clinical course and prognosis in Mexican patients with EMM.Aims:To analyze and describe the impact of EMM on overall survival (OS) and progression free survival (PFS) of Mexican patients diagnosed and treated at monoclonal gammapathies clinic of our institution.MethodsRetrospective analysis including &gt;18 year‐old patients with MM diagnosis according to IMWG criteria. EMM was defined as presence of CPC corroborated by immunohistochemistry in BP or TP or demonstration of a synchronous tumor by imaging method and no accessible to biopsy.Results:A total of 199 patients were included. Sixty‐three patients had EMM (31.8%), 45 cases (71.4%) presented at diagnosis and 18 (28.6%) at progression. Forty‐eight cases (76.2%) were diagnosed by biopsy and 15 (23.8%) by imaging. Fifty‐four percent (n = 34) cases presented BP and 46% (n = 29) TP. Most frequently involved sites were abdomen (34.5%), thorax (27.6%) and lymph nodes (13.8%) in TP and spine (50%), chest wall (26.3%) and head/neck (13.2%) in BP. EMM was associated with lower comorbidity rate and higher renal failure. Population characteristics are shown in Table 1. Mean PFS and OS was 22.9 and 43.7 months, respectively. EMM at any time of disease resulted on lower PFS and OS (p = 0.03, p = 0.04), while TP showed lower OS (p &lt; 0.01). A higher ECOG PS and lower deep response was associated with worse PFS (HR 1.05‐2.60 (p = 0.03) and HR 0.20‐0.38 (p &lt; 0.01), respectively) while ISS and lower deep response resulted on worse OS (HR 1.0‐2.2 (p = 0.02) and HR 0.37‐0.73 (p &lt; 0.01)) at multivariate regression.Summary/Conclusion:A higher EMM rate was found in the studied population. EMM was associated to higher renal failure and low incidence of comorbidities, as shorter PFS and OS, particularly in TP. Identification of this high risk myeloma population allows an attempt for more intensive treatment with intention to improve prognosis.image

Epidemiology of Plasma Cell Leukemia in the Czech Republic.

Plasma cell leukemia (PCL) is arare but most aggressive form of monoclonal gammopathies. PCL is characterized by the presence of clonal plasma cells in peripheral blood. There are two forms of PCL - primary which presents denovo in patients with no evidence of previous multiple myeloma and secondary which is aleukemic transformation of relapsed or refractory dis-ease in patients with previously recognized multiple myeloma. This is the first study to provide information on PCL epidemiology in the Czech population us-ing The Czech National Cancer Registry (CNCR) as the basic source of data for the population-based evaluation of PCL epidemiology. Accord-ing to CNCR data, there were on average six newly dia-gnosed cases of PCL and four deaths caused by PCL each year in the Czech Republic in the period 2000-&#8202;2015. PCL incidence in the Czech Republic was reported at 0.57per million in 2000-&#8202;2015. We suppose that most reported cases of PCL are primary PCL because secondary PCL is arelapse of apreviously reported myeloma and, in most cases, is not coded as an independent dia-gnosis in the CNCR. Data from registries such as the CNCR can provide useful information on epidemiology of various dis-eases. These data, however, have several limitations, such as dia-gnostic criteria and proper cod-ing of not only the dis-ease itself, but also its various forms. These limitations have to be taken into account dur-ing the process of results interpretation. Key words plasma cell leukemia-&#8202; epidemiology-&#8202; Czech National Cancer Registry (CNCR)-&#8202; Czech Republic.

Circulating Plasma Cells in Monoclonal Gammopathies.

Monoclonal gammopathies are characterized by presence of clonal plasma cells in the bone marrow, although peripheral blood circulating plasma cells can be found in a significant proportion of patients. The number of circulating plasma cells is an independent prognostic marker associated with shorter survival, but it can also help to predict early relapse. The reason and mechanism of plasma cell expansion from the bone marrow to enter peripheral blood is still not entirely clear, but possible changes in the expression of adhesion molecules are probably involved. Multiparametric flow cytometry allows simple and exact enumeration of circulating plasma cells in different types of cell suspensions, even in their low quantity. The phenotype profile and confirmation of clonality regarding to their bone marrow clonal counterparts should be verified as well. There is no uniform method used in clinical laboratories for circulating plasma cells analyses at this moment. Review is focused on use of multiparametric flow cytometry for circulating plasma cells analysis in peripheral blood. It is comparing possibilities of their detection by different methods and on clinical relevance of that assessment. The standardization of analyses is the main goal. Multiparametric flow cytometry is a very sensitive method for detection of circulating plasma cells, so using a standardized approach can lead to determination and implementation of the flow cytometry diagnostic threshold in plasma cell leukemia suspicious cases as well as in prognostication of monoclonal gammopathies patients. Moreover, analysis of plasma cells phenotypic profile could probably clarify their future behaviour.Key words: monoclonal gammopathies - circulating plasma cells - plasma cell leukemia - flow cytometry.

A case report of a young female with plasma cells leukemia

Plasma cell leukemia (PCL) is a rare and aggressive variant of plasma cell dyscrasias that can occur either de novo (primary) or as a leukemic transformation of end-stage multiple myeloma (MM). PCL is known with a poor prognosis and with a different biologic background, clinical, and laboratory features. Primary PCL presents more often with extramedullary involvement, anemia, thrombocytopenia, hypercalcemia, elevated serum 2-microglobulin, and lactate dehydrogenase levels, in addition to impaired renal function in comparison with MM. Here, we report a case of a young female who was admitted with excessive thirst, polyuria, lower backache, fever, and weight loss over 2 months. Peripheral blood smear showed numerous atypical looking plasma cells, and immunophenotyping on bone marrow (BM) aspirate demonstrated the presence of clonal plasma cells. She was admitted to adult hematology ward in Hiwa Hemato-Oncology Hospital, Sulaimani, Kurdistan, Iraq and received four cycles of bortezomib, thalidomide, and dexamethasone chemotherapy, followed by two more cycles of dexamethasone, cyclophosphamide, etoposide, and cisplatin, and later, she proceeded to autologous BM transplantation. More details of the case are presented below.