Residual Disease In Multiple Myeloma Research Articles

Euroflow-Based Ultrasensitive NGF for the Evaluation of Bone Marrow Minimal Residual Disease in Multiple Myeloma

Background: Euroflow next-generation flow cytometry sensitively assesses minimal residual disease (MRD) in multiple myeloma (MM). It is widely adopted in labs worldwide for tracking disease progression, therapy efficacy, and decision-making in MM trials. Euroflow MRD significantly enhances MM patient outcomes, alongside advancements in anti-cancer approaches like BiTEs, CAR-T cells, and ADCs, resulting in increased overall survival rates. However, blood-based methods do not always align with bone marrow PC analysis, requiring heightened sensitivity to detect residual malignant cells post-therapy. The recent BloodFlow method, achieves remarkable sensitivity up to 10 -8 by enriching CD138 + PCs from 50 mL peripheral blood. In this study, we compare conventional Euroflow BM-MRD with the ultrasensitive method using CD138 enrichment of BM cells before analysis. Methods: BM-MRD followed Euroflow group guidelines. For ultrasensitive assessment, CD138 + plasma cells were isolated using CD138 MicroBeads. Data analysis was performed with Infinicyt software. Automatic gate and identification tool was used for conventional MRD, while data was manually analyzed for ultrasensitive MRD assessment. Results: We compared conventional and ultrasensitive MRD in the bone marrow of 70 MM patients. All positive MRDs using conventional NGF remained positive with ultrasensitive MRD. Notably, among 40 patients with negative conventional NGF-MRD, 5 cases turned positive after ultrasensitive MRD, by detecting aPCs from 0,0003 to 0,002% in all nucleated cells in the bone marrow. Patients 1, 2, and 3, diagnosed between 2020 and 2022, were in CR during assessment. Patients 4 and 5, diagnosed in 2016 and 2014 respectively, underwent multiple therapies, two autologous hematopoietic cell transplants, and patient 5 also had an allogeneic hematopoietic cell transplant. Ultrasensitive MRD for patients 4 and 5 was done after anti-BCMA CAR T cell therapy. The CD138 isolation approach allowed evaluating BM-MRD at detection levels of 10 -8 cells. Further studies using ultrasensitive MRD will prospectively evaluate the predictive value of the assay in patients with NDMM, especially with high and ultra-high-risk disease. Conclusions: This study demonstrates the significant advantages of direct CD138 enrichment over bulk lysis for detecting residual malignant PCs in MM. Ultrasensitive MRD offers superior sensitivity compared to conventional MRD, a critical factor in the era of more effective therapies leading to deeper responses. Currently, we are prospectively assessing the clinical benefits in a larger patient cohort.

P-075 Real-world evidence on prognostic value of minimal residual disease in multiple myeloma: Czech experience

P-075 Real-world evidence on prognostic value of minimal residual disease in multiple myeloma: Czech experience

Minimal Residual Disease in Multiple Myeloma: Past, Present, and Future.

Responses to treatment have improved over the last decades for patients with multiple myeloma. This is a consequence of the introduction of new drugs that have been successfully combined in different clinical contexts: newly diagnosed, transplant-eligible or ineligible patients, as well as in the relapsed/refractory setting. However, a great proportion of patients continue to relapse, even those achieving complete response, which underlines the need for updated response criteria. In 2014, the international myeloma working group established new levels of response, prompting the evaluation of minimal residual disease (MRD) for those patients already in complete or stringent complete response as defined by conventional serological assessments: the absence of tumor plasma cells in 100,000 total cells or more define molecular and immunophenotypic responses by next-generation sequencing and flow cytometry, respectively. In this review, we describe all the potential methods that may be used for MRD detection based on the evidence found in the literature, paying special attention to their advantages and pitfalls from a critical perspective.

Liquid biopsy-based monitoring of residual disease in multiple myeloma by analysis of the rearranged immunoglobulin genes-A feasibility study.

The need for sensitive monitoring of minimal/measurable residual disease (MRD) in multiple myeloma emerged as novel therapies led to deeper responses. Moreover, the potential benefits of blood-based analyses, the so-called liquid biopsy is prompting more and more studies to assess its feasibility. Considering these recent demands, we aimed to optimize a highly sensitive molecular system based on the rearranged immunoglobulin (Ig) genes to monitor MRD from peripheral blood. We analyzed a small group of myeloma patients with the high-risk t(4;14) translocation, using next-generation sequencing of Ig genes and droplet digital PCR of patient-specific Ig heavy chain (IgH) sequences. Moreover, well established monitoring methods such as multiparametric flow cytometry and RT-qPCR of the fusion transcript IgH::MMSET (IgH and multiple myeloma SET domain-containing protein) were utilized to evaluate the feasibility of these novel molecular tools. Serum measurements of M-protein and free light chains together with the clinical assessment by the treating physician served as routine clinical data. We found significant correlation between our molecular data and clinical parameters, using Spearman correlations. While the comparisons of the Ig-based methods and the other monitoring methods (flow cytometry, qPCR) were not statistically evaluable, we found common trends in their target detection. Regarding longitudinal disease monitoring, the applied methods yielded complementary information thus increasing the reliability of MRD evaluation. We also detected indications of early relapse before clinical signs, although this implication needs further verification in a larger patient cohort.

Comparison of next-generation flow cytometry and next-generation sequencing in the assessment of minimal residual disease in multiple myeloma

Comparison of next-generation flow cytometry and next-generation sequencing in the assessment of minimal residual disease in multiple myeloma

Microfluidic isolation of aptamers with affinity towards multiple myeloma monoclonal immunoglobulins.

Multiple myeloma (MM) is a bone marrow cancer of resident plasma cells that affects 125,000 patients in the U.S. with about 30,000 new cases per year. Its signature is the clonal proliferation of a single plasma cell that secretes a patient specific monoclonal immunoglobulin (M-Ig). Targeting the M-Ig in patient serum could allow sensitive and noninvasive identification of minimal residual disease in multiple myeloma. Aptamers, which are single-stranded oligonucleotides with affinity and specificity to a target molecule, have recently been introduced as affinity reagents for recognition of MM M-Igs. Here we exploit microfluidic SELEX technology to enable rapid and efficient generation of aptamers against M-Ig proteins from MM patients. We first characterize the technology by isolating aptamers with affinity towards the monoclonal antibody rituximab as a model M-Ig and then apply the technology to isolating aptamers specifically targeting M-Igs obtained from serum samples of MM patients. We demonstrate that high-affinity DNA aptamers (KD < 50 nM) for M-Ig proteins from a patient sample could be isolated via microfluidic SELEX within approximately 12h and using less than 100 micrograms of patient M-Ig. Such aptamers can potentially be used in personalized monitoring of minimal residual disease in MM patients.

Comparison of Next-Generation Flow Cytometry (NGF) and Next-Generation Sequencing (NGS) in the Assessment of Minimal Residual Disease in Multiple Myeloma

Background:Next generation flow cytometry (NGF) and next generation sequencing (NGS) are standard methods for detection of minimal residual disease (MRD) in multiple myeloma (MM) according to domestic and international guidelines. However, due to the inability to standardize laboratory technology among hospitals, the results are unreliable. In order to meet the challenges of data evaluation and comparability between studies in multiple myeloma (MM) minimal residual disease (MRD) assessment，and to further confirm the role of MRD in evaluating deep remission，we provide a approach to evaluate and compare the efficacy of each patient after treatment by NGF and NGS concurrently. Methods: In a VRD clinical study in our center, a cohort analysis was performed on 82 patients with newly diagnosed multiple myeloma in the First Affiliated Hospital of Soochow University from September 01, 2019 to January 31, 2022.Bone marrow (BM) sample from 82 MM patients were analyzed by NGS and NGF MM MRD methods during treating procedure. Limit of detection (LOD) and tumor load (TL) were calculated, and the concept of MRD negative was defined. At the same time, step-by-step statistics and analysis of MRD results were carried out to confirm its role in evaluating the depth of remission, and to analyze and compare whether the two methods were consistent and the difference in detection rate, evaluating the prediction of patient survival by MRD detection. Results:Among the 82 patients, 100.00% of NGF specimens and 96.34% of NGS specimens met the LOD criteria of 1.0e-5. Non-detection of tumor cells at the 1.0e-5 level was defined as NGF-MRD-negative or NGS-MRD-negative. After induction therapy, the positive detection rate of NGS was higher than that of NGF (81.01% vs 51.22%). The patients who did not achieve VGPR serological response were all MRD positive. The positive rate of NGF-MRD was 42.25%, and the positive rate of NGS-MRD was 78.26% in patients with serological response reaching VGPR or above. With the deepening of serological efficacy: from PR to VGPR to CR and sCR, the positive rate of MRD gradually reduced（NGF：100.00%-70.37%-25.00%；NGS：100.00%-96.15%-67.44%). The median tumor load was progressively decreased (NGF: 10-3-10-4-10-6 level; NGS: 10-1-10-2-10-4 level). Compared with NGF, NGS not only has a higher positive detection rate, but also can detect more tumor load. Pairing the NGF-MRD and NGS-MRD results, the agreement between the two methods (NGF+NGS+ and NGF-NGS-) was 63.77%, and the Pearson correlation coefficient indicated a certain correlation in TL quantification (n=54 , r=0.4371, P=0.001). Conclusion: An MRD assessment (at least a 10-5 level) should be performed after obtaining a serologic response to VGPR and above. When analyzing MM-MRD, the LOD value should be marked and the definition of MRD negative should be stated. Compared with NGF, NGS not only has a higher positive detection rate of MRD (67.44% vs 25.00%), but also can detect more tumor load and has higher sensitivity in patients with CR or above after induction therapy. NGF MRD positivity predicts shorter PFS and earlier relapse after induction therapy. NGF and NGS MRD negativity predicts 100.00% in 2-year PFS. Keywords: multiple myeloma (MM); minimal residual disease (MRD); next-generation flow cytometry (NGF); next-generation gene sequencing (NGS); line of detection (LOD); tumor load (TL) Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Clonotypic Mass Spectrometry with Easym Assay for Detection of Measurable Residual Disease in Multiple Myeloma

The presence of measurable residual disease (MRD) is an important prognostic factor for multiple myeloma. However, MRD tests in current clinical use require bone marrow (BM) samples that are uncomfortable, expensive, and time-consuming for patients. BM-based assays are also limited by sampling of a single location within the marrow, which may not accurately represent overall disease burden. Consequently, there is an urgent unmet need for peripheral blood-based MRD testing that would allow for convenient, repeated assessment of MRD. M-protein quantification using mass spectrometry (MS) is promising candidate methodology for peripheral blood MRD monitoring due to its exceptional analytical sensitivity. Specifically, "clonotypic" MS techniques can identify and track a specific M-protein "peptide fingerprint", allowing sensitive and specific measurement of MRD that may exceed BM-based techniques. However, clinical data regarding this approach is limited and no clonotypic MS assays are currently in clinical practice. Consequently, we performed a pilot study to assess the use of clonotypic MS-based MRD testing using the EasyM system (Rapid Novor, Kitchener, ON). We retrospectively identified a subset of patients in our institutional tissue bank who met the following criteria: 1) IgG multiple myeloma, 2) M-protein ≥0.5 g/dL by serum protein electrophoresis (SPEP) at diagnosis, and 3) adequate samples for analysis. Baseline and follow up serum samples were analyzed by the study sponsor in a blinded fashion. EasyM results were subsequently compared to SPEP and, when available, next generation sequencing MRD testing with the clonoSeq assay (Adaptive, Seattle, WA). We used receiver-operator curve analysis to identify cutoffs for percent reduction in EasyM to predict BM-based MRD using the R package "cutpointr". 19 patients were identified for analysis. Median age was 62 and 52% were male. All patients received proteasome inhibitor-based induction and 17 patients received lenalidomide. All underwent autologous stem cell transplant (ASCT) in first remission. A clonotypic signature was identified in all 19 patients from the baseline sample. 54 follow up samples were analyzed. Percent change in EasyM and SPEP were well correlated (Pearson R = 0.808; p < 0.01). 37 timepoints had MRD testing available. Of these, 14 and 9 timepoints were negative at 10-5 and 10-6, respectively; only 3 (8%) had undetectable M-protein by EasyM, all MRD negative at 10-6. Using receiver-operator curve analysis, we identified optimal cutoffs for percent reduction in EasyM by area under the curve for BM-based MRD at 10-5 (99.0%) and 10-6 (99.3%) thresholds. The PPV and NPV for EasyM at 10-5 were 91% and 80%. The PPV and NPV for EasyM at 10-6 were 92% and 58%. Given the half-life of IgG (2 - 3 weeks), we also performed an exploratory analysis for MRD at 10-5 separating day 100 samples (n = 18) from later samples (n = 18). This analysis yielded slightly different optimal cutoffs for percent reduction by EasyM for day 100 (98.2%) versus later timepoints (99.4%), with similar PPV (91% and 92%) and improved NPV (100% for both), suggesting time of sample collection may impact the predictive value of EasyM. At day 100 after ASCT, 7 patients were in CR, 9 in VGPR and 3 in PR. 7 patients progressed during the follow up period. One patient had undetectable EasyM at day 100 after ASCT and received only 4 months of post-ASCT lenalidomide, but remains in CR over 3 years after transplant. Two patients achieved undetectable EasyM at 9 and 55 months, respectively, post-ASCT and remain in CR at 52 and 64 months. Our study provides initial data regarding clonotypic MS with the EasyM assay for peripheral blood MRD testing. We demonstrated excellent correlation between percent reduction in M-protein by SPEP and EasyM. Interestingly, 79% of samples that were MRD negative at 10-5 by clonoSeq had detectable M-protein by clonotypic MS, suggesting EasyM may be a more sensitive test for residual disease. After optimization, EasyM showed excellent PPV and NPV for BM-based MRD negativity, suggesting clonotypic MS be able to identify patients who can forego a bone marrow biopsy for MRD monitoring. We are currently validating this assay in non-IgG isotypes and light chain disease. Overall, clonotypic MS represents a promising new tool for myeloma monitoring and should be performed in larger retrospective cohorts and integrated into prospective trials for further validation.

Enhanced Global Disease Assessment with Advanced Imaging and Targeted Myeloma Lesion Biopsy Highlights Spatial Heterogeneity and Detects Residual Disease in Multiple Myeloma

Background: Multiple myeloma (MM) is a biologically complex disease with marked heterogeneity; limitations remain in our standard myeloma disease assessment at diagnosis and in response to therapy. In this study, we aimed to prospectively investigate the utilization of advanced imaging and targeted focal lesion (FL) biopsies to augment global disease evaluation, detect residual tumor burden, and explore the diverse histologic and molecular landscape of this multifocal neoplasm. Herein, we present our final analysis of this clinical trial. Methods: Adult patients with newly diagnosed clinical MM (NDMM) and bone or extramedullary (EM) FL were eligible to participate in this prospective study. Advanced imaging with positron emission tomography/computed tomography (PET/CT) or whole body magnetic resonance imaging (WB-MRI), standard bone marrow (BM) biopsy and aspiration, and targeted FL biopsy were performed at enrollment and after four 28-day cycles of induction therapy with carfilzomib (36 mg/m2 intravenously twice weekly), lenalidomide (25 mg orally days 1-21), and dexamethasone (40 mg orally weekly) (KRd), with dose modifications as needed. Conventional clinical response, using IMWG Response Criteria (Kumar S et al, 2016), was also measured after each cycle of treatment. Patients were followed for 12 months after end of treatment or until data cutoff on February 23rd, 2022. Results: 27 patients were enrolled in this study between June 2018 and August 2021, with 25 evaluable for global response assessment. Median age was 61 years (range, 42-76 years) and 14.8% of patients were of Black or African American race. 85.2% of patients had Revised International Staging System (R-ISS) stage II or III disease. 51.9% of patients were identified as having EM disease arising out of bone or soft tissue and 44.4% of patients had high risk cytogenetics inclusive of chromosome 1 abnormalities. In sum, 70.4% of our cohort had at least 1 high risk feature at diagnosis (Table 1). 80% of patients had myeloma FL identified on advanced imaging that were missed on conventional skeletal survey. Of the 7 patients with cytogenetic and fluorescence in situ hybridization (FISH) testing performed on initial FL biopsy, 6 (85.7%) had findings discrepant from those seen on cytogenetic testing from standard BM samples. 9 patients had cytogenetic and FISH studies on repeat myeloma FL biopsy after KRd induction with 2 showing residual FISH abnormalities that were not detected on standard BM obtained for response assessment. Clinical response rates after 4 cycles of KRd were high in our study population with 88% of patients achieving a very good partial response (VGPR) or better and 20% with a stringent complete response (sCR) with minimal residual disease (MRD) negativity by flow cytometry. However, of the 22 patients with ≥VGPR by IMWG response assessment, 18 had residual disease on advanced imaging with WB-MRI (10 patients), PET/CT (7 patients), or MRI total spine (1 patient), including 3 of the 5 patients with sCR (Figure 1). 2 patients experienced disease progression during the study period with median progression free survival not reached by the patient cohort. Both patients with progression had a VGPR by conventional response assessment, though with residual FL on advanced imaging post-KRd induction. Conclusions: While tumor spatial differences in MM have been observed retrospectively, prospective data on this important component of myelomagenesis is limited. In our cohort of high risk NDMM, we demonstrated spatial heterogeneity both at diagnosis and after KRd induction. Despite the deep clinical responses observed by IMWG response assessment, 81.8% of patients with ≥VGPR had ongoing abnormalities on advanced imaging which could potentially serve as disease reservoirs for future progression and development of treatment resistance. A novel assessment method in MM, inclusive of advanced imaging and targeted FL biopsies, may overcome the limitations of our standard response assessment with resultant improved knowledge of the varied intra-tumor disease biology as well as development of more refined treatment approaches. A potential limitation of our study is the smaller sample size with underrepresentation of minority populations. Data on whole exome sequencing of paired BM and FL biopsies will be reported separately. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Flow Cytometric Analysis of Bone Marrow Particle Cells for Measuring Minimal Residual Disease in Multiple Myeloma.

Simple SummaryThe hemodilution of bone marrow aspirates is the main factor affecting the reliability of the determination of the minimal residual disease (MRD) resulting in multiple myeloma (MM). A bone marrow particle cell (BMPL) enrichment assay may be applied to overcome the problems caused by the hemodilution of bone marrow aspirates and to improve the rate of myeloma cell detection. Assessment of BMPL samples could decrease the false-negative rate of the MRD assessed with routine bone marrow aspirates. This study validated that the BMPL was superior to the routine bone marrow aspirate samples in the MM and MRD analysis.Minimal residual disease (MRD) is one of the most relevant prognostic factors in patients with multiple myeloma (MM). However, the hemodilution of bone marrow (BM) aspirates, the most common preanalytical problem, is known to affect MRD detection. In the present study, we analyzed a preanalytical method for routine BM aspirates and a bone marrow particle cell (BMPL) enrichment assay and validated it as a reliable preanalytical method for flow cytometric MRD determination. A total of 120 BM samples were taken from 103 MM patients consecutively recruited; 77 BM samples had BMPL enrichment analysis and 99 BM samples were routinely analyzed. Then, the two different samples from patients with MM were sent for MRD detection using an eight-color flow cytometry. Our data showed that assessment of the BMPL enrichment samples attenuated the overestimation of MRD-negative assessed in the routine BM samples, which was mainly caused by hemodilution. In conclusion, the BMPL enrichment assay is a functional and practical preanalytical method for flow cytometric MRD analysis.

Minimal Residual Disease in Multiple Myeloma—Current Approaches and Future Clinical Implications

The prognosis and clinical outcomes for patients with multiple myeloma have improved significantly over the past two decades. A substantial number of patients now achieve complete remission after induction therapy, and more sensitive methods are needed to assess response. Minimal or measurable residual disease (MRD) has been incorporated in many clinical trials as well as in clinical practice. The importance of MRD assessment and correlation between MRD negativity and prolonged progression-free and overall survival has been confirmed in numerous clinical trials and several meta-analyses. Recent studies have even suggested that MRD negativity can partly overcome the impact of the negative prognostic factors such as high-risk cytogenetics or adverse revised international scoring system (R-ISS) stage. MRD can be measured in the bone marrow via imaging and via emerging blood-based techniques. The most common methods are multicolor flow cytometry and next-generation sequencing of bone marrow samples. Using these methods in optimal settings, MRD negativity with a sensitivity level of 10−6 can be detected. In this review, we discuss the benefits and limitations of these techniques as well as the clinical implications.

Key markers for diagnosis of minimal residual disease in multiple myeloma

Introduction. Therapeutic advances in recent years, the appearance on the market each time of new drugs that allow patients to achieve complete remission, a long period without progression dictate the need to control treatment by monitoring residual disease in multiple myeloma. Monitoring of multiple myeloma is the detection of a small number of tumor cells after therapy in a patient, which may be the cause of recurrence of the disease – control of minimal residual disease (MRD). This article discusses the key diagnostic markers (CD45, CD56 and CD19) of minimal residual multiple myeloma disease at initial diagnosis and after induction therapy. There are various diagnostic methods of research that can reliably assess the response to therapy and predict the occurrence of relapse. The main methods for detecting MRD are allele-specific polymerase chain reaction, next-generation sequencing and multicolor flow cytometry. The diagnosis of MRD by flow cytometry is the most widely used quite fast, quantitative, sensitive and affordable method, it is used for the primary diagnosis of multiple myeloma, as well as for monitoring MRD. It is important to identify the aberrant immunophenotype during the initial diagnosis for the correct subsequent assessment of MRD. MRD of multiple myeloma is considered an important component in the course of patient therapy before hematopoietic stem cell autotransplantation to assess the effectiveness of therapy, control and prognosis of the disease.The aim of the work MRD-study with the key diagnostic markers in multiple myeloma (CD45, CD56 and CD19).Materials and methods. The study was carried out in 59 patients with multiple myeloma. For all patients, in addition to standard methods of diagnosis and staging of the disease, bone marrow morphology (myelogram) and immunophenotype were examined. Eight-color flow cytometry with a panel of monoclonal antibodies for the diagnosis of plasma cell tumors Euro-Flow 2012 was used to diagnose MRD.Results. MRD was assessed by markers CD45, CD56 and CD19 in patients with multiple myeloma after induction therapy. The incidence of MRD-positivity for CD45 was 87.5 %, for CD56 – 97.5 %, for CD19 – 95.5 %. The incidence of MRD-negative status was for CD45 was 12.5 %, for CD56 – 2.5 % and for CD19 – 4,5 %.Conclusion. The use of a complex of these markers allows the most accurate determination of the MRD-negative status, taking into account the primary immunophenotype of malignant plasma cells.

Minimal Residual Disease in Multiple Myeloma: an Important Tool in Clinical Trials.

Minimal residual disease (MRD) detection represents a great advancement in multiple myeloma. New drugs are now available that increase depth of response. The International Myeloma Working Group recommends using next-generation flow cytometry (NGF) or next-generation sequencing (NGS) to search for MRD in clinical trials. Best sensitivity thresholds have to be confirmed, as well as timing to detect it. MRD has proven as the best prognosticator in many trials and promises to enter also in clinical practice to guide future therapy.

Drug resistance and minimal residual disease in multiple myeloma.

Great progress has been made in improving survival in multiple myeloma (MM) patients over the last 30 years. New drugs have been introduced and complete responses are frequently seen. However, the majority of MM patients do experience a relapse at a variable time after treatment, and ultimately the disease becomes drug-resistant following therapies. Recently, minimal residual disease (MRD) detection has been introduced in clinical trials utilizing novel therapeutic agents to measure the depth of response. MRD can be considered as a surrogate for both progression-free and overall survival. In this perspective, the persistence of a residual therapy-resistant myeloma plasma cell clone can be associated with inferior survivals. The present review gives an overview of drug resistance in MM, i.e., mutation of β5 subunit of the proteasome; upregulation of pumps of efflux; heat shock protein induction for proteasome inhibitors; downregulation of CRBN expression; deregulation of IRF4 expression; mutation of CRBN, IKZF1, and IKZF3 for immunomodulatory drugs and decreased target expression; complement protein increase; sBCMA increase; and BCMA down expression for monoclonal antibodies. Multicolor flow cytometry, or next-generation flow, and next-generation sequencing are currently the techniques available to measure MRD with sensitivity at 10-5. Sustained MRD negativity is related to prolonged survival, and it is evaluated in all recent clinical trials as a surrogate of drug efficacy.

The Importance of Complementary Immunological Markers in the Diagnosis of Minimal Residual Disease in Multiple Myeloma

Background. The population of non-tumor plasma cells in healthy subjects’ bone marrow is known to be fairly heterogeneous. Among them, there may be a small number of CD19-, CD56+, CD45- plasma cells which differ from the main bulk of the normal plasmacytic cells by the lack of CD19 and CD45 expression and the presence of CD56 expression. It is the fact which makes the monitoring of minimal residual disease (MRD) especially challenging in multiple myeloma (MM) since normal and aberrant plasma cells should be compared. For this reason, a study of such complementary diagnostic markers as CD27, CD28, CD117, and CD81 is extremely important. Aim. To analyze the role of complementary diagnostic markers (CD27, CD28, CD117, and CD81) of MRD in MM patients at different disease stages. Materials &amp; Methods. The present study enrolled 62 MM patients aged 31-76 years (median 58 years); 25 women and 37 men. The analysis focused on morphological and immunophenotypic properties of bone marrow plasma cells. MRD was detected by 8-color flow cytometry with the use of FACSCanto II Flow Cytometer (USA) based on EuroFlow standards. Results. At the stage of primary diagnosis of MM, the imunophenotype of plasma cells was analyzed in all 62 patients using two 8-color panels recommended by the EuroFlow Consortium (2012). In accordance with primary immunophenotyping data, MRD was evaluated on the basis of not only the main diagnostic markers of plasma cells (CD38, CD138, CD45, CD56, and CD19), but also the complementary ones, such as CD27, CD28, CD117, and CD81. The study was basically conducted after induction therapy and upon remission. With cut-off &gt; 0.01 % of aberrant plasma cells, the MRD incidence was the following: 91.0 % with CD27, 90.6 % with CD28, 87.0 % with CD117, and 96.7 % with CD81 markers. Respectively, no MRD was detected in 9.0 % with CD27, 9.4 % with CD28, 13.0 % with CD117, and 3.3 % with CD81 markers.

Will Mass Spectrometry Replace Current Techniques for Both Routine Monitoring and MRD Detection in Multiple Myeloma?

In recent years, mass spectrometry has been increasingly used for the detection of monoclonal proteins in serum. Mass spectrometry is more analytically sensitive than serum protein electrophoresis and immunofixation, can help distinguish therapeutic monoclonal antibodies from M-proteins, and can detect the presence of post-translational modifications. Mass spectrometry also shows promise as a less-invasive, peripheral-blood-based test for detecting minimal residual disease in multiple myeloma. Studies comparing the clinical utility of mass spectrometry to current blood- and bone-marrow-based techniques have been conducted. Although still primarily limited to research settings, clinical laboratories are starting to adopt this technique for patient care. This review will discuss the current status of mass spectrometry testing for multiple myeloma, the benefits and challenges of this technique, and how it may be incorporated into clinical practice in the future.

Is it time to tailor treatment on the basis of minimal residual disease in multiple myeloma?

Is it time to tailor treatment on the basis of minimal residual disease in multiple myeloma?

Detection of Clonal Plasma Cells in POEMS Syndrome Using Multiparameter Flow Cytometry

Detection of Clonal Plasma Cells in POEMS Syndrome Using Multiparameter Flow Cytometry

Daratumumab and Lenalidomide Maintenance Guided by Minimal Residual Disease in Multiple Myeloma

Daratumumab and Lenalidomide Maintenance Guided by Minimal Residual Disease in Multiple Myeloma

P-037: Serum-free light chain and heavy-light chains normalization as markers for negative measurable residual disease in Multiple Myeloma after autologous stem cell transplant

<h3>Background</h3> Measurable residual disease (MRD) in Multiple Myeloma is widely recognized of significant importance in prognosis. Multi-parameter flow cytometry (MFC) on bone marrow is one of the most chosen techniques to evaluate MRD. Nonetheless, it needs a bone marrow aspiration and time points could be limited due to the invasiveness of the evaluation. Serum-free light chains (sFLC) and heavy-light chains (HLC) assays have high sensitivity to detect blood circulating monoclonal proteins and infer immune reconstitution. They could be used as a peripheral surrogate marker for MRD. <h3>Aim</h3> Evaluate the correlation between the MFC-MRD negativity and the normalization of sFLC and sHLC in patients with MM after autologous stem cell transplant (ASCT). <h3>Methods</h3> 27 patients transplanted with IgG or IgA MM were included in this analysis. y. Assays (sFLC, sFLC on serum; MFC on bone marrow) were performed on all patients at a median of 100 days post-ASCT. The kappa/lambda sFLC ratio (FLCr) and involved/uninvolved HLC ratio (HLCr) were used to assess responses using published normal ranges. International Myeloma Working Group (IMWG) response criteria were used to classify treatment responses. MFC was performed according to the Euroflow panel with 10^-5 sensitivity. Contingency tables were used to compare the serum biomarkers versus the MRD. Positive (PPV) and negative predictive value (NPV) were calculated by Fisher exact. <h3>Results</h3> HLCr normalized in 18/27 (67%) patients, with FLCr normalization in 13/27 (48%) at 100 days post-ASCT. MFC-MRD negativity at 100 days post-ASCT was noted in 15/27 (56%). Patients. Post-ASCT HLCr and FLCr normalization was found in 9 patients (60%) with MRD negativity. Comparization of MFC MRD negativity and HLCr and FLCr normalization tests showed 86.7% sensitivity, 58.3% specificity, 72% PPV, and 77% NPV (Fisher Test p=0.037). <h3>Conclusions</h3> Despite the high percentage of patients with normal HLCr and FLCr in patients in MRD negativity at day 100 post-ASCT, ours results demonstrates that HLCr and FLCr normalization does lack sensitivity when compared to MFC-MRD. HCLr and FLCr could be used in patients with negative MRD to follow patients in more time points to predict relapse and prompt a bone marrow MRD evaluation. This work will be validated in a larger cohort of post-ASCT multiple myeloma patients, taking into account follow-up, namely prediction of relapse and progression-free survival.