Plasma Cell Myeloma Residual Disease Quantitation Using a Next-Generation Sequencing-Based IGH Clonal Rearrangement Assay with the Aid of a "Spike-in" Clonal Sequence

Introduction: Next-generation sequencing (NGS)-based IGH clonal rearrangement assays can characterize and subsequently track disease-associated clonal sequences for lymphoid and plasma cell neoplasms, even at very low levels. As IGH PCR primers are used, the detected clonal sequences are usually reported as % of sequencing reads, roughly corresponding to % of B and plasma cells (PC) in samples, rather than % of total cellularity, hampering accurate disease burden assessment. In this study, we evaluated a method for calculating residual disease burden as % of total cellularity, with the aid of adding a known quantity of "spike-in" clonal sequence to the samples, and compared to concurrent 10-color flow cytometry (FC) quantitation of abnormal PC. Methods: DNA was extracted from 40 plasma cell myeloma patient marrow biopsies sent for disease monitoring purposes at Memorial Sloan Kettering Cancer Center (MSKCC), with previously-characterized clonal sequences specific to the patients' myelomas. All samples had concurrent FC analyses and aspirate differential counts performed. 100 cell equivalent of DNA with a known clonal sequence (LymphoQuant®, LQ) was added to 700ng of patient DNA (~100,000 cell equivalent), and testing was performed using LymphotrackTM, a NGS-based assay. Following PCR amplification using IGH FR1 primers, sequencing was performed on the Illumina MiSeqTM instruments at the molecular laboratory of MSKCC. Reproducibility studies were conducted on a subset of samples at the laboratory of Invivoscribe, Inc. using identical methodology. LymphoTrack MRD data analysis tool (MRDDAT) v.1.0.3 was used to search for both the myeloma-specific and LQ clonal sequences. Disease as # of cell equivalent was calculated as: (% reads for myeloma clonal sequence/% reads for LQ) X 100 cells. Disease as % of total cellularity was calculated as: (# of cell equivalent/100,000 cells) X 100%. Results: Disease as % of total cellularity calculated by LQ showed a median of 0.7576% cells (range: 0.000614% to 39.89%), compared to abnormal PC as % of total WBC by FC with a median of 0.355% cells (range: 0.00061% to 44.70%). Overall, a good correlation between disease quantitation by LQ and FC could be observed for cases with ≤10% total PC by aspirate count (r=0.79), while the correlation is lower for cases with >10% total PC (r=0.51). 12/40 samples were tested in two different laboratories, and showed excellent correlation in disease quantitation by LQ (r=0.94). As expected, detectable clonal sequences as % of sequencing reads (rather than as % of total cellularity) showed poor correlation with FC quantitation (r=0.32), due to variability of total B and plasma cell content in different samples. Conclusions: Disease as % of total cellularity calculated with the aid of a known "spike-in" sequence in the NGS-based assay showed good correlation with the quantitation of abnormal PC by FC, when total PC was ≤10% by aspirate count. The correlation between the two declines when total PC was >10%. When patient samples contain a high number of B and/or plasma cells, the PCR amplification efficiency of the very small amount of the admixed "spike-in" clonal sequence may be hampered, affecting accurate quantitation. Furthermore, FR1 primers may not anneal optimally to some patients' clonal sequences due to somatic hypermutations in binding sites, underestimating the % of disease clone. Utilization of a second "spike-in" sequence and other primer sets (FR2, FR3) may improve disease % calculations in some cases. Disclosures Ho: Invivoscribe, Inc.: Honoraria. Roshal:Celgene: Other: Provision of Services; Auron Therapeutics: Equity Ownership, Other: Provision of services; Physicians' Education Resource: Other: Provision of services. Huang:Invivoscribe, Inc.: Employment. Hutt:Invivoscribe, Inc.: Employment. Miller:Invivoscribe, Inc.: Employment. Landgren:Theradex: Other: IDMC; Abbvie: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Merck: Other: IDMC; Adaptive: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Arcila:Invivoscribe, Inc.: Consultancy, Honoraria.

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In Vitro and inVivo Activity of Melflufen in Amyloidosis

Blood ◽

10.1182/blood-2019-125952 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3100-3100 ◽

Cited By ~ 2

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.

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B-Cell Maturation Antigen (BCMA) in Systemic Light-Chain Amyloidosis (AL): Association with Disease Activity and Its Modulation with Gamma-Secretase Inhibition

Blood ◽

10.1182/blood-2019-126988 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4409-4409 ◽

Cited By ~ 2

Author(s):

Amandeep Godara ◽

Ping Zhou ◽

Benjamin Rosenthal ◽

Adin Kugelmass ◽

Denis Toskic ◽

...

Keyword(s):

Cell Surface ◽

Disease Activity ◽

Board Of Directors ◽

Plasma Cell ◽

Light Chain ◽

Research Funding ◽

San Diego ◽

Plasma Cells ◽

Advisory Committees ◽

Nsg Mice

Introduction: Systemic light-chain (AL) amyloidosis results from clonal plasma cells that secrete toxic fibril-forming free light chains. Therapies directed at the plasma cell clone form the backbone of its management. Identification of cell-surface receptors on the clonal cells can provide targets for therapy. BCMA is one such cell-surface glycoprotein; it is principally expressed on plasma cells and supports their long-term survival (J Exp Med. 2004;199:91-98). Anti-BCMA immunotherapies are currently being studied in multiple myeloma (N Engl J Med. 2019;380:1726-1737). Membrane-bound BCMA (mBCMA) is also shed as a soluble form, sBCMA, due to γ-secretase activity that can be inhibited by a small molecule (GSI, LY-411575) (Nat Commun. 2015;6:7333; J Immunol. 2017;198(8):3081-3088). We report on mBCMA on the clonal plasma cells of AL patients and its modulation by GSI in vitro, and on sBCMA in the blood of AL patients and of mice xenografted with an AL cell line, demonstrating its correlations in vivo with free light chain (FLC) levels and plasma cell tumor burden. Methods: We analyzed mBCMA and sBCMA levels in marrow aspirate and peripheral blood samples from AL patients under an IRB approved protocol. We isolated mononuclear cells (MNC) from patient marrow aspirates with anti-CD138 microbeads (Miltenyi Biotec, Auburn, CA), and used the CD138-selected cells in culture with LY-411575 (Sigma Aldrich, St Louis, MO). We analyzed mBCMA expression by flow cytometry using APC conjugated anti-CD269 (BCMA) antibody (Biolegend, San Diego, CA, USA) and CD138 expression by PE-conjugated anti-CD138 antibody (Biolegend, San Diego, CA, USA), along with appropriate isotype controls. We injected 107 ALMC-1 reporter cells in the flanks of NOD scid gamma (NSG) mice to create a xenograft model of AL clonal plasma cell disease (Jackson Laboratories, Bar Harbor, ME). sBCMA in patients and mice and FLC in mice were measured by ELISA (R&D Systems, Minneapolis, MN; Bethyl lab Montgomery, TX respectively). Pearson and Spearman correlation analysis was used to examine associations of sBCMA and clinical disease parameters. Paired t-test was applied to compare BCMA expression before and after treatment with GSI. Results: Marrow and blood were obtained from 20 AL patients, 8 newly diagnosed, 4 with progression of disease, and 8 after treatment with >VGPR. Their median age was 65 years (range, 48-77) and 50% were female. Median plasma cells in the marrow aspirates and involved FLC levels were 5% (1-20%) and 33 mg/L (6.6-2220mg/L) respectively. Median mBCMA expression on CD138+ marrow MNC and sBCMA levels in plasma were 39% (4-83) and 28.5 ng/ml (6.6-100.3) respectively (Figure 1A-B). sBCMA levels correlated with bone marrow plasma cell percentage and iFLC (both p<0.001, Figure 1C-D). In culture with LY-411575, the percentages of CD138 cells positive for mBCMA increased from 85% to 100% with ALMC-1 cells and from 36% to 68% (p < 0.01) with patient CD138-selected cells while the sBCMA levels in culture supernatant decreased by over 50%. In NSG mice with ALMC-1 reporter cell xenografts, medians of luciferin-based bioluminescence FLUX (photons/s), λ FLC and sBCMA were 3.9x1010 (2.02x109-1.2x1011), 949.1 mg/L (868.8-23629.2), and 3.8 ng/ml (0.9-23.6) respectively. sBCMA levels correlated with FLC (Pearson r= 0.99, p<0.0001) and with FLUX (Pearson r=0.61, p=0.07). Conclusions: BCMA is expressed on AL plasma cells and sBCMA is detected in the blood of all AL patients. In this light chain disease, sBCMA may be useful as a marker of disease activity even in patients with low FLC. Furthermore, expression of mBCMA can be manipulated by treatment with a GSI, an approach which may be useful therapeutically in AL. These results provide the basis for applying anti-BCMA immunotherapies in clinical trials in relapsed refractory AL patients. Disclosures Comenzo: Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Unum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; Caelum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; Prothena Biosciences: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Myself: Patents & Royalties: Patent 9593332, Pending 20170008966.

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Moffitt Cancer Center 2-Year Single-Institution Experience with Next-Generation Sequencing Minimal Residual Disease Detection: Clinical Utility, Application, and Correlation with Outcomes in Plasma Cell and Lymphoid Malignancies

Blood ◽

10.1182/blood-2019-129846 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4654-4654 ◽

Cited By ~ 1

Author(s):

Mohammad O Hussaini ◽

Jaya Srivastava ◽

Lik Wee Lee ◽

Taiga Nishihori ◽

Bijal Shah ◽

...

Keyword(s):

Board Of Directors ◽

Plasma Cell ◽

Research Funding ◽

Residual Disease ◽

Cancer Center ◽

Employment Equity ◽

Advisory Committees ◽

Lymphoid Malignancies ◽

Equity Ownership ◽

Generation Sequencing

Background: Measuring residual disease during the continuum of care is fundamental to oncology practice. In particular, minimal residual disease (MRD) assessments and trends over time can help inform clinical management, including change in treatment regimen or treatment discontinuation. In patients (pts) with plasma cell and lymphoid malignancies, next-generation sequencing (NGS)-MRD is a valuable tool for assessing MRD and depth of response to treatment. MRD status is strongly prognostic of time to relapse and overall survival in multiple myeloma (MM), acute lymphoblastic leukemia (ALL), mantle cell lymphoma (MCL), and chronic lymphocytic leukemia (CLL). In this report, we summarize our 2-year experience with clinical implementation of NGS-MRD (clonoSEQ®) testing across a spectrum of plasma cell and lymphoid disease. Methods: This retrospective analysis summarizes our experience using the NGS-MRD Assay (Adaptive Biotechnologies, Seattle, WA) in plasma cell and lymphoid malignancies. The assay uses multiplex polymerase chain reaction (PCR) and NGS to identify, characterize, and monitor unique disease-associated sequence rearrangements or clonotypes of immunoglobulin (Ig) IgH (V-J), IgH (D-J), IgK, and IgL receptor gene sequences, and translocated BCL1/IgH (J) and BCL2/IgH (J) sequences in DNA extracted from high disease burden diagnostic (ID) and post-treatment (MRD) samples. PCR amplification bias control ensures a quantitative read-out of the full B-cell receptor repertoire present in the ID sample and provides direct measure of tumor burden. Our study included pts with plasma cell and lymphoid malignancies, including MM, ALL, CLL, and MCL treated at the Moffitt Cancer Center between March 2017 and March 2019 who had provided at least an ID sample for NGS-MRD testing. Results: A total of 423 ID tests using DNA from bone marrow (BM; n=407) or peripheral blood (PB; n=16) and 384 MRD tracking tests (BM, n=321; PB, n=63) were performed in 297 pts (Table). The median turnaround time from shipment arrival to assay initiation was 2.1 hours and from activation to report date was 7.1 days. For MM, ALL, MCL, and CLL, the numbers of tests ordered, calibration rates (defined as proportion of ID samples with trackable sequence[s]), and mean number of trackable sequences are shown in the Table. More ID tests were ordered than number of pts (range: 108-178%) due to multiple tests performed for each patient. Sequences analyzed for MRD tests included IgH, IgK/IgL, and T-cell receptors β and γ. The proportion of pts with detectable MRD is shown by indication in the Table. In MM, autologous stem cell transplant (autoSCT)-eligible pts or those who achieved excellent initial responses but were transplant-ineligible, were primarily considered for NGS-MRD testing as part of standard of care. NGS-MRD testing was performed prior to autoSCT and post-SCT before initiation of maintenance therapy for prognostication. More than 90% of MM cases with successful NGS-MRD results had trackable clones. Negative NGS-MRD assured excellent disease control and supported the decision to discontinue therapy in some pts with significant toxicities. In pts with ALL, treatment response after induction and/or consolidation guided decision-making for allogeneic (allo) SCT at first remission. MRD burden prior to alloSCT could potentially guide the decisions and timing on performing SCT or conditioning regimen intensity. In pts with MCL, treatment response evaluated by NGS-MRD following 6 cycles of therapy was a decision point in a randomized trial of auto-transplant + rituximab vs rituximab alone (ClinicalTrials.gov: NCT03267433). MRD is also being used to guide the duration of rituximab maintenance therapy. Updated data analysis for all indications, including CLL, is underway and will be presented at the meeting. Conclusions: The NGS-MRD Assay is a highly sensitive diagnostic tool for the observation of deeper disease response to therapy in multiple specimen types and in various lymphoid and plasma cell malignancies. NGS-MRD may assist in therapeutic decision-making or prognostication. NGS-MRD is a sensitive and powerful prognostic tool available for the majority of pts, which will help our understanding of the role of MRD in clinical management of plasma cell and lymphoid malignancies. Table Disclosures Srivastava: Adaptive Biotechnologies: Employment, Equity Ownership. Lee:Adaptive Biotechnologies: Employment, Equity Ownership. Nishihori:Novartis: Research Funding; Karyopharm: Research Funding. Shah:AstraZeneca: Honoraria; Pharmacyclics: Honoraria; Adaptive Biotechnologies: Honoraria; Spectrum/Astrotech: Honoraria; Novartis: Honoraria; Celgene/Juno: Honoraria; Kite/Gilead: Honoraria; Incyte: Research Funding; Jazz Pharmaceuticals: Research Funding. Alsina:Janssen: Speakers Bureau; Amgen: Speakers Bureau; Bristol-Myers Squibb: Research Funding. Baz:Merck: Research Funding; Sanofi: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Research Funding. Pinilla Ibarz:Abbvie: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; Sanofi: Speakers Bureau; Bayer: Speakers Bureau; TG Therapeutics: Consultancy; Teva: Consultancy; Janssen: Consultancy, Speakers Bureau. Shain:Adaptive Biotechnologies: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; AbbVie: Research Funding; Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees.

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Utilizing Multiparametric Flow Cytometry to Identify Patients with Primary Plasma Cell Leukemia at Diagnosis

Blood ◽

10.1182/blood-2019-126777 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4334-4334 ◽

Cited By ~ 1

Author(s):

Laura A Evans ◽

Dragan Jevremovic ◽

Bharat Nandakumar ◽

Francis K. Buadi ◽

Angela Dispenzieri ◽

...

Keyword(s):

Board Of Directors ◽

Plasma Cell ◽

Peripheral Blood ◽

Research Funding ◽

Blood Smear ◽

Plasma Cells ◽

Peripheral Blood Smear ◽

Optimal Cutoff ◽

Advisory Committees ◽

Multiparametric Flow Cytometry

INTRODUCTION: Primary plasma cell leukemia (pPCL) is the most aggressive form of multiple myeloma (MM). Recently, pPCL has been defined by as few as >5% circulating plasma cells (cPCs) detected morphologically on a peripheral blood smear. However, this technique may not be sufficiently sensitive and is dependent on inter-observer bias to properly identify and quantify cPCs. Multiparametric flow cytometry (MFC) provides a readily available and highly sensitive method to identify and quantify cPCs. However, an optimal quantitative cutoff for cPCs by MFC to define the presence of pPCL has not been established to date. Thus, this is the first study to date that determines an optimal cutoff of cPCs/ microliter that could identity patients with pPCL at diagnosis. METHODS: We retrospectively evaluated all newly diagnosed MM patients seen at the Mayo Clinic, Rochester from January 2007 to December 2017 who had their peripheral blood samples evaluated morphologically by peripheral blood smear and immunophenotypically by MFC prior to beginning therapy. Patients with a peripheral blood smear detecting >5% cPCs were classified as having pPCL. Six-color MFC was performed on peripheral blood mononuclear cells by isolated by Ficoll gradient, and stained with antibodies to CD45, CD19, CD38, CD138 and cytoplasmic Kappa and Lambda immunoglobulin light chains. The data was collected using Becton Dickinson FacsCanto II instruments collecting 150,000 events and analyzed using the BDFacs DIVA Software. The gating strategy employed first used the expression of CD38, CD138, and cytoplasmic immunoglobulin light chains to identify all plasma cells in the specimen. The cPCs were then discriminated from polyclonal/normal plasma cells based on differential CD19 and CD45 expression. The cPCs detected were reported as the number of clonal events/150,000 collected total events and converted to the absolute number of cPCs/microliter using their absolute lymphocyte count and monocyte count determined at the time of the blood draw for cPC MFC assessment. A receiver operator curve (ROC) was performed to determine the absolute cPCs/microliter by MFC that best identified those patients with >5% cPC on their peripheral blood smear. Survival analysis was performed by the Kaplan-Meier method and differences assessed using the log rank test. RESULTS: A total of 591 patients were included in this analysis of which 59% were male and the median age was 66 years (range: 27 - 95) with 22% being 75 years of age or older. From this cohort, 133 (24%) patients had high risk FISH cytogenetics, 172 (30%) were classified as ISS 3 at diagnosis, 83 (15%) had an elevated LDH level and 61 (17%) had a plasma cell labeling index (PCLI) of 2% or greater. There were 65 (11%) patients with any amount of cPCs detectable by peripheral blood smear of which only 22 (4% of the total population) met criteria for pPCL with >5% cPCs. With MFC, 403 (68%) patients had detectable cPCs. The median number of cPCs per microliter was 0.81 (0 - 10,455) with 273 (46%) having >1 cPC/microliter. A ROC analysis determined that the presence of >50 cPCs/microliter by MFC was the optimal cutoff to identify patients with >5% cPCs by blood smear with approximately a specificity of 94% and a sensitivity of 86%. The presence of >50 cPCs/microliter by MFC was associated with higher presence of high risk FISH cytogenetics, ISS 3 classification, elevated LDH and PCLI > 2%. The median time to next treatment (TTNT) for patients with and without >5% cPCs by peripheral blood smear was 18 months vs. 30 months (P < 0.001). The median TTNT for patients with and without >50 cPCs/microliter by MFC was 19 months vs. 30 months (P < 0.01). The median overall survival (OS) for patients with and without >5% cPCs by peripheral blood smear was 25 months vs. 71 months (P < 0.001; Fig 1A). The median OS for patients with and without >50 cPCs/microliter by MFC was 38 months vs. 71 months (P < 0.01; Fig 1B). CONCLUSION: This is the largest study that attempts to identify an optimal cutoff of cPCs/microliter by MFC for diagnosing pPCL patients. The presence of >50 cPCs/microliter is an optimal cutoff by MFC that best predicts for the presence of >5% cPCs by peripheral blood smear. However, there remains discordance in the OS outcomes between the two cutoffs by different methodologies for pPCL. This could signify the presence of biological processes associated with the presence of >5% cPCs when detected by peripheral blood smear that are not captured by MFC. Disclosures Dispenzieri: Pfizer: Research Funding; Janssen: Consultancy; Intellia: Consultancy; Akcea: Consultancy; Alnylam: Research Funding; Takeda: Research Funding; Celgene: Research Funding. Dingli:Karyopharm: Research Funding; Rigel: Consultancy; Millenium: Consultancy; Janssen: Consultancy; alexion: Consultancy. Lacy:Celgene: Research Funding. Kapoor:Amgen: Research Funding; Takeda: Honoraria, Research Funding; Glaxo Smith Kline: Research Funding; Sanofi: Consultancy, Research Funding; Cellectar: Consultancy; Janssen: Research Funding; Celgene: Honoraria. Leung:Aduro: Membership on an entity's Board of Directors or advisory committees; Omeros: Research Funding; Prothena: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding. Russell:Imanis: Equity Ownership. Gertz:DAVA oncology: Speakers Bureau; Ionis/Akcea: Consultancy; Alnylam: Consultancy; Prothena Biosciences Inc: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Spectrum: Consultancy, Research Funding; Annexon: Consultancy; Appellis: Consultancy; Amgen: Consultancy; Medscape: Consultancy, Speakers Bureau; Physicians Education Resource: Consultancy; Abbvie: Other: personal fees for Data Safety Monitoring board; Research to Practice: Consultancy; Teva: Speakers Bureau; Johnson and Johnson: Speakers Bureau; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Proclara: Membership on an entity's Board of Directors or advisory committees; i3Health: Other: Development of educational programs and materials; Springer Publishing: Patents & Royalties; Amyloidosis Foundation: Research Funding; International Waldenstrom Foundation: Research Funding. Kumar:Takeda: Research Funding; Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding.

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Oncogene Induced Senescence As a Potential Breakpoint Mechanism Against Malignant Transformation in Plasma Cell Disorders

Blood ◽

10.1182/blood.v128.22.4474.4474 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4474-4474

Author(s):

Nicola Lehners ◽

Elena Ellert ◽

Jing Xu ◽

Hartmut Goldschmidt ◽

Mindaugas Andrulis ◽

...

Keyword(s):

Multiple Myeloma ◽

Board Of Directors ◽

Malignant Transformation ◽

Plasma Cell ◽

Research Funding ◽

Plasma Cells ◽

Healthy Controls ◽

Advisory Committees ◽

Expression Levels ◽

Plasma Cell Disorders

Abstract Background: Cellular senescence has been recognized as a failsafe mechanism against hyperproliferation and might thus be induced by DNA replicative stress and oncogenic signaling, commonly termed oncogene-induced senescence (OIS). OIS has been described in several premalignant conditions such as colon adenomas and melanocytic nevi, with impaired OIS capabilities found in their malignant counterparts. Here, we analyze the possible impact of cellular senescence on malignant transformation in plasma cell disorders. Methods: Bone marrow and soft tissue biopsies from 125 patients with different stages of plasma cell disorders (16 monoclonal gammopathy of undetermined significance (MGUS), 32 smoldering multiple myeloma (SMM), 56 symptomatic multiple myeloma (MM), 21 extramedullary MM) as well as from 10 healthy donors were analyzed. Expression of OIS associated proteins p16INK4A, p21Cip1/Waf1, p27Kip1, phospho-Chk2, the DNA double-strand break marker γH2AX, as well as the proliferation marker Ki67 were assessed on plasma cells by immunohistochemistry. Additionally, double staining experiments for p21 and Ki67 were performed applying immunofluorescence confocal microscopy. Levels of protein expression were compared between different disease stages using the Kruskal-Wallis test. Results: A differential expression pattern was found for p21 in various stages of plasma cell disorders with peak expression of p21 in SMM compared to both healthy controls (p<0.001) and MGUS (p=0.02), as well as compared to symptomatic multiple myeloma (MM) (p=0.007) (see Figure 1a). Median p21 expression was 0.63% of plasma cells from healthy subjects, 6.67% in MGUS, 13.81% in SMM, 2.37% in MM, and 0% in EMM. Plasma cells of SMM patients expressing p21 were negative for Ki67 consistent with a potentially senescent phenotype. In contrast, p27 was highly expressed in healthy controls, MGUS and SMM but decreased significantly in MM patients (p=0.02) (see Figure 1b). p16 showed no nuclear expression in healthy controls, MGUS or SMM and was expressed only in few patients with MM. In addition, we found low expression of p21, p27 and phospho-Chk2 in extramedullary MM compared to medullary MM samples, accompanied by increased expression of γH2AX and high levels of proliferation (Ki67 58%). Conclusions: We found indication of induction of OIS in SMM compared to symptomatic MM, mainly mediated by increased expression of p21. Further disease progression to extramedullary MM was characterized by almost complete absence of OIS markers and increased signs of DNA damage and proliferation. These observations are consistent with the hypothesis of OIS as a breakpoint mechanism against malignant transformation in plasma cell disorders and should be further explored mechanistically and as a possible therapeutic target. Figure 1 Expression levels of p21 and p27in different stages of plasma cell disorders. Semiquantitative assessment of plasma cells positive for p21 (a) and p27 (b) is shown in healthy controls, MGUS, SMM, MM, and EMM patients. Significant differences in expression levels between cohorts are indicated by their respective p-values with * p-value < 0.05, ** < 0.01, *** < 0.001. Figure 1. Expression levels of p21 and p27in different stages of plasma cell disorders. Semiquantitative assessment of plasma cells positive for p21 (a) and p27 (b) is shown in healthy controls, MGUS, SMM, MM, and EMM patients. Significant differences in expression levels between cohorts are indicated by their respective p-values with * p-value < 0.05, ** < 0.01, *** < 0.001. Disclosures Goldschmidt: Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Chugai: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Raab:Novartis: Consultancy, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy.

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Next-Generation Sequencing-Based Assay Shows High Clonal Characterization Success Rate for Plasma Cell Neoplasms, and Concordance with Flow Cytometry in Minimal Residual Disease Detection

Blood ◽

10.1182/blood-2018-99-115690 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4475-4475

Author(s):

Caleb Ho ◽

Mustafa Syed ◽

Mikhail Roshal ◽

Kseniya Petrova-Drus ◽

Christine Moung ◽

...

Keyword(s):

Success Rate ◽

Board Of Directors ◽

Plasma Cell ◽

Research Funding ◽

Residual Disease ◽

Complete Response ◽

Patient Specific ◽

Advisory Committees ◽

Plasma Cell Neoplasms ◽

Generation Sequencing

Abstract Introduction After therapy or stem cell transplantation, multiple myeloma patients achieving complete response (CR) or stringent complete response (sCR) can still have a significant risk of disease relapse, illustrating the importance of using highly sensitive methods for minimal residual disease (MRD) detection and prognostication. Two techniques used clinically for MRD detection include multiparametric flow cytometry (FC), which has a sensitivity down to 2-6 X 10-6 of cells, and next-generation sequencing (NGS)-based assay for detection of patient-specific clonal IGH VDJ gene sequences associated with the neoplastic plasma cells (PC). We determined the clonal characterization success rate of plasma cell neoplasm samples from a single institution in a clinical lab, using a commercially available NGS-based assay, Lymphotrack® (Invivoscribe, San Diego, CA). The characterized clonal sequences were used for MRD detection in subsequent monitoring samples, and the results were compared to concurrent FC findings. Methods DNA was extracted from fresh marrow or formalin-fixed paraffin-embedded (FFPE) tissue, and amplified by PCR reactions using primers sets for IGH Leader, FR1, FR2, FR3 regions, and IGK. Sequencing was performed on the Illumina MiSeqTM Platform, and sequence analyses were performed using the Lymphotrack® software, and MSK-Lymphoclone, a software developed at our institution. Disease-associated clonal sequences were characterized based on predefined clonal calling criteria and stored. In subsequent samples sent for disease monitoring, a search for sequencing reads with high homology (>99%) to the patient-specific sequences was performed for MRD detection. 10-color FC for PC analyses were also performed on the same samples at our institution (Roshal M, et al. Blood Adv 2017;1(12):728-32), with a target minimum of 3 million cells for MRD analyses. Results Overall, clonal characterization was successful in 235/251 cases (93.6%), with no difference in number of sequencing reads between the successful and unsuccessful cases (p=0.24). Higher success rate was observed among cases with higher aspirate PC counts: ≥5% (95.6% success rate) and ≥10% (98.1% success rate). IGH FR1 and Leader primers together characterized 214/251 cases (85.3%), while the remaining cases required additional primers. The characterized clones showed high median somatic hypermutation (SHM) rate of 8.1% (range: 0.0-29.0%), as well as IGH V and J segment usage bias: V3 (50.2%), followed by V4 (20.3%); J4 (43.4%), followed by J6 (27.5%), concordant with prior literature. 187 samples from 124 unique patients were tested by the Lymphotrack® assay for monitoring purposes, of which the diagnostic clones were detected in 147/187 samples (78.6%), with no difference in number of sequencing reads between cases with and without detectable clone (p=0.35). Within the short median time interval of 9.5 months between the characterization and monitoring samples, most clonal sequences remained stable. In 2 cases, new clonal sequences emerged in subsequent samples. Overall, FC and Lymphotrack® showed high concordance rate for MRD detection (92.9%) (See figures). All discordant cases showed <5% PC by aspirate differential counts and CD138 immunostains. FC+/NGS- cases (9/184, 4.9%) showed abnormal PC comprising a median of 0.00095% of WBC by FC, while FC-/NGS+ cases (4/184, 2.2%) showed detectable clone at a median of 0.0405% of sequencing reads. Sampling differences might have contributed to the discrepancies. Additionally, in the FC+/NGS- cases, neoplastic subclones might be present at very low level in the characterization samples, below threshold for clonal calling, and therefore could not be specifically tracked in subsequent samples. Conclusions Our study demonstrated high clonal characterization success rate for plasma cell neoplasms using the Lymphotrack® assay when multiple primers sets were used, and the assay showed concordance with FC in MRD detection for the majority of cases. MRD detection sensitivity can be limited by low sample concentration/volume. Furthermore, the presence of very low level neoplastic subclones in the characterization samples might hamper clonal calling and detection in subsequent samples. Disclosures Ho: Invivoscribe, Inc.: Honoraria. Landgren:Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy; Karyopharm: Consultancy. Arcila:Invivoscribe, Inc.: Consultancy, Honoraria.

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Evolution of Multiparametric Flow Cytometry Testing for Minimal Residual Disease Assessment in Multiple Myeloma and Its Impact on Clinical Outcomes: A Single Institution Experience

Blood ◽

10.1182/blood.v128.22.2274.2274 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2274-2274 ◽

Cited By ~ 1

Author(s):

Nischala Ammannagari ◽

Paul K. Wallace ◽

Theresa Hahn ◽

Yali Zhang ◽

Christine M. Ho ◽

...

Keyword(s):

Multiple Myeloma ◽

Flow Cytometry ◽

Board Of Directors ◽

Clinical Outcomes ◽

Research Funding ◽

Plasma Cells ◽

Residual Disease ◽

Advisory Committees ◽

Multiparametric Flow Cytometry ◽

Minimal Residual

Abstract Minimal residual disease (MRD) after autologous hematopoietic cell transplant (AHCT) in multiple myeloma (MM) has been shown to be an important predictor of clinical outcomes, suggesting that MRD negativity may be a new goal of therapy. Multiparametric flow cytometry (MFC) is a commonly used method for MRD assessment, however this technique is still evolving and efforts are underway to standardize this testing. The key factors which enable detection of residual malignant plasma cells by MFC remain an area of active investigation. We performed a retrospective review of 172 consecutive MM patients who received AHCT between 10/1/2007 and 5/31/2015 at our institution and had undergone MRD assessment by MFC at day +100 post-AHCT. Day +100 post-AHCT response was determined using the International Myeloma Working Group (IMWG) Uniform Response Criteria (URC) and was correlated with MRD assessment as well as progression free survival (PFS) and overall survival (OS). Data were collected on the specific MFC panel utilized, including the epitopes analyzed and the total plasma cell number (PCN) counted (normal and malignant PC). These variables were correlated with clinical outcomes including day +100 MM response, PFS and OS. Of 172 patients, 30 were MRD-positive, 133 MRD-negative, and 9 were equivocal at day +100 post-AHCT, the latter of which were excluded from further analyses. Day+100 MRD-negative status by MM response was: 31/37(84%) for VGPR, 35/41 (85%) for CR, and 42/42 (100%) for sCR. Patients who achieved a CR or sCR had improved PFS and OS rates compared with patients who achieved ≤VGPR: 3-year PFS: 61% (95% CI 49-74%) vs 46% (95% CI 32-59%), P=0.03; 3-year OS: 96% (95% CI 91-100%) vs 69% (95% CI 56-81%), P=0.005)). Patients with MRD-negative disease at day +100 post-AHCT had significantly superior PFS and OS compared to those with MRD-positive disease: 3-yr PFS 62% (95% CI 52-72%) vs 33% (95% CI 12-53%), P <0.0001) (Figure 1); 3-year OS 85% (95% CI 78-93%) vs 64% (95% CI 44-85%), P=0.004). There was no association between MRD status and age (<60 vs ≥60 years), sex, race (white vs other), performance status (KPS ≤80 vs ≥90), or subsequent transplant (P>0.1). The details of the four different MRD MFC panels are shown in Table 1. Panels C and D were compared, at a similar PCN level, but different epitopes tested, and found no significant difference in PFS or OS. Further analysis of PCN within the MRD-negative cohort revealed a trend towards improved 3-yr PFS rates with increasing numbers of PCN analyzed: 42% (95% CI 20-63%) for PCN<250,000, 68% (95% CI 52-83%) for PCN=250,000-500,000, 59% (95% CI 42-76%) for PCN >500,000-1,000,000 and 89% (78-100%) for PCN>1,000,000 (P=0.099) (Figure 2). The 3-yr OS rates for MRD-negative patients were higher for increasing PCNs analyzed, but the PCN categories were not statistically significantly different: 74% (95% CI 54-94%) for PCN<250,000, 88% (95% CI 77-99%) for PCN=250,000-500,000, 85% (95% CI 73-98%) for PCN >500,000-1,000,000 and 100% for PCN>1,000,000 (P=0.2). Sensitivity analysis revealed similar trends when a cut-off of above or below 500,000 or 1,000,000 was used. Our results confirm that achievement of MFC MRD negativity at day +100 post-AHCT is associated with improved PFS and OS. Factors such as the long-half lives of immunoglobulins, the quality of the bone marrow aspirate obtained, and the presence of occult extramedullary disease may account for the patients who were MRD negative but did not achieve a CR at day +100 post AHCT by IMWG URC. MRD assessment by MFC at our institution has evolved over time to include higher numbers of acquired and analyzed events. Notably, there was a trend towards improved outcomes with greater numbers of plasma cells analyzed, suggesting that continued development of MRD assessment by MFC should focus on increasing PCN analyzed in order to improve detection of residual MM clones. Disclosures Hahn: Novartis: Equity Ownership; NIH: Research Funding. McCarthy:The Binding Site: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gamida Cell: Honoraria, Membership on an entity's Board of Directors or advisory committees. Holstein:Millennium: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

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V(D)J Sequence Capture for DNA-Based Minimal Residual Disease Detection in Multiple Myeloma

Blood ◽

10.1182/blood-2018-99-113889 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4444-4444

Author(s):

Even H Rustad ◽

Malin Hultcrantz ◽

Venkata D Yellapantula ◽

Theresia Akhlaghi ◽

Caleb Ho ◽

...

Keyword(s):

Bone Marrow ◽

Tumor Cell ◽

Board Of Directors ◽

Plasma Cell ◽

Research Funding ◽

Bone Marrow Aspirate ◽

Plasma Cells ◽

Advisory Committees ◽

Cell Content ◽

Capture Rates

Abstract Introduction Minimal residual disease (MRD) negativity after initial therapy is a strong predictor of survival in multiple myeloma. Tracking of clonal immunoglobulin V(D)J rearrangements by next generation sequencing is highly sensitive for MRD and does not require immediate analysis of fresh samples. However, previous studies have found variable rates of baseline V(D)J sequence capture, which could limit tracking. In this study, we aimed to define the sample-related and disease-related factors that influence V(D)J capture. Methods We included 177 patients with plasma cell myeloma who had available stored mononuclear cells from a baseline bone marrow aspirate. Each sample was sequenced by two assays: The LymphoTrack® VDJ assays from Invivoscribe, and our in-house myeloma panel myTYPE, as a molecular control for detectable tumor derived DNA in the samples. MyTYPE positivity was defined by one or more single nucleotide variant, insertion, deletion, translocation or copy number variation that is known to occur in myeloma. Results and discussion The V(D)J capture rate in our whole cohort was 81 %, as compared with 95 % in the myTYPE positive samples, demonstrating the importance of tumor cell content for V(D)J capture. This was confirmed in multivariate logistic regression (Figure 1), where myTYPE positivity was a strong independent predictor of V(D)J capture success, with an odds ratio (OR) of 6.61 (95 % CI 2.22-24.81, p = 0.002). Plasma cell content estimated from bone marrow aspirate smears also contributed to the multivariate model, with an OR of 1.3 for each 10 % increase in plasma cell content (95 % CI 0.96-1.84, p=0.109), but this did not reach statistical significance after accounting for the strong effect of myTYPE. Finally, having lambda light chain restricted plasma cells was a strong predictor of V(D)J capture success (OR 6.91, 95 % CI 2.4-25.32, p = 0.001). Higher V(D)J capture rate in lambda-restricted myeloma as compared with kappa-restricted was mostly driven by a difference in immunoglobulin kappa gene (IGK) rearrangement capture (73 vs. 44 %, p < 0.001). As a potential explanation, we found up to 4 unique IGK rearrangements that are amenable to capture in lambda-restricted cases, as well as dramatically lower somatic hypermutation (SHM) of the IGK variable region in clonal rearrangements, as compared with kappa-restricted cases. SHM has previously been shown to cause V(D)J capture failure by interfering with PCR primer annealing. Both of these factors can be attributed to IGK inactivation by rearrangements involving the "kappa deleting element" region, affecting both IGK alleles in lambda-restricted plasma cells (Perfetti et al, Immunology, 2004). As an explanation for low plasma cell content in the samples used in this study, we describe how the tumor cell content of bone marrow aspirates decrease gradually in sequential pulls because of hemodilution: from the initial pull used for aspirate smear, to the final pull that is commonly used for research. Supporting the important role of hemodilution, we found V(D)J capture rates of 97 % in clinical samples (early pull aspirates) from our institution that were analyzed with the same NGS assays, as long as the bone marrow plasma cell infiltration was above 5 %. V(D)J capture probability appears to be determined by two factors: The abundance of clonal cells (i.e. tumor cell content), and the degree to which clonal sequences can be amplified by the assay (which is negatively affected by SHM). Thus, increasing the tumor cell content in samples as much as practically possible (i.e., optimal bone marrow aspirates and enrichment of CD138+ plasma cells) may compensate for SHM and improve V(D)J capture rates beyond 95 %. Conclusion V(D)J capture rates of at least 95 % are feasible in multiple myeloma using LymphoTrack® NGS assays, when the sample quality is good. The most important reason for V(D)J capture failure is low tumor cell content due to bone marrow aspirate hemodilution. Optimal performance depends on the use of early pull aspirates and/or subsequent tumor cell enrichment. Figure 1: Predicting V(D)J capture. Regression lines and individual data points are colored according to myTYPE status (red = positive; blue = negative); V(D)J capture probability on the y-axis (capture yes/no on the second y-axis) and bone marrow plasma cell percentage by aspirate smear on the x-axis; split into panels according to light chain restriction (right = lambda; left = kappa). Disclosures Ho: Invivoscribe, Inc.: Honoraria. Arcila:Invivoscribe, Inc.: Consultancy, Honoraria. Jacobsen:Invivoscribe, Inc.: Employment. Huang:Invivoscribe, Inc.: Employment. Miller:Invivoscribe, Inc.: Employment, Equity Ownership. Landgren:Pfizer: Consultancy; Karyopharm: Consultancy; Amgen: Consultancy, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Primary Plasma Cell Leukemia Outcomes Remain Dismal Despite Novel Agents and Hematopoietic Cell Transplantation

Blood ◽

10.1182/blood-2019-127049 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 266-266

Author(s):

Sagar Patel ◽

Saulius K. Girnius ◽

Binod Dhakal ◽

Lohith Gowda ◽

Raphael Fraser ◽

...

Keyword(s):

High Risk ◽

Board Of Directors ◽

Plasma Cell ◽

Research Funding ◽

Hematopoietic Cell Transplantation ◽

Disease Status ◽

Cell Leukemia ◽

Advisory Committees ◽

Primary Plasma Cell Leukemia ◽

Equity Ownership

Background Primary plasma cell leukemia (pPCL) is a rare plasma cell neoplasm with a high mortality rate. There have been improvements in multiple myeloma (MM) outcomes with novel induction agents and use of hematopoietic cell transplantation (HCT) with maintenance, but similar progress has not been reported for pPCL. We examined the outcomes of pPCL patients receiving novel agents with autologous (autoHCT) or allogeneic (alloHCT) approaches as reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) in the modern era. Methods From 2008 to 2015, 348 pPCL pts underwent HCT (N = 277 - autoHCT and 71 - alloHCT) with 45% and 48% having research level data available, respectively. Cumulative incidences of non-relapse mortality (NRM) and relapse/progression (REL), and probability of progression-free survival (PFS) and overall survival (OS) were calculated. Cox multivariate regression was used to model survival after autoHCT only. Median follow-up in autoHCT and alloHCT was 48 and 60 months, respectively. Results AutoHCT Cohort Median age was 60 years and 93% received HCT within 12 months of diagnosis with 76% after a single line of induction (Table 1). 35% had high risk cytogenetics. 23% received bortezomib, doxorubicin, cisplatin, cyclophosphamide, and etoposide (VDPACE). Moreover, 40% received bortezomib (BTZ) and immunomodulatory drug (IMIID)-based triplets. Disease status at HCT was VGPR or better in 47%. 27% received maintenance therapy. At 4 years post-HCT, NRM was 7% (4-11%), REL 76% (69-82%), PFS 17% (13-23%), and OS 28% (22-35%) (Figures 1A, 2A, 2B). Disease status ≥VGPR at HCT and Karnofsky Performance Score >90 significantly predicted superior OS in multivariate analysis. AlloHCT Cohort Median age was 53 years and 89% received HCT within 12 months of diagnosis (Table 1). 61% received a single alloHCT, while 39% used auto-alloHCT tandem approach. 42% had high-risk cytogenetics. 61% received total body irradiation with 44% receiving myeloablative conditioning. Use of VDPACE was higher at 41% in this cohort. VGPR status at HCT was similar (48%), while maintenance was used less often (12%). Grade II-IV acute GVHD occurred in 30% and chronic GVHD in 45%. At four years post-HCT, NRM was 12% (5-21%), REL 69% (56-81%), PFS 19% (10-31%), and OS 31% (19-44%) (Figures 1A, 1B, 2A, 2B). There were no differences in outcomes based on type of HCT. A comparison of post-HCT outcomes of CIBMTR pPCL patients from 1995 to 2006 showed that PFS and OS outcomes are inferior despite lower NRM in this modern cohort (Mahindra et al. Leukemia. 2012). In addition, analysis of SEER (1995-2009) and CIBMTR databases showed that use of HCT increased from 12% (7-21%) in 1995 to 46% (34-64%) in 2009. Conclusion More newly diagnosed pPCL patients are receiving modern induction regimens translating into a higher proportion receiving HCT, but without significant further benefit post-HCT. Post-HCT relapse remains the biggest challenge and further survival in pPCL will likely need a combination of targeted and cell therapy approaches. This study provides a benchmark for future HCT studies for pPCL. Disclosures Girnius: Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Dhakal:Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria. Shah:University of California, San Francisco: Employment; Indapta Therapeutics: Equity Ownership; Genentech, Seattle Genetics, Oncopeptides, Karoypharm, Surface Oncology, Precision biosciences GSK, Nektar, Amgen, Indapta Therapeutics, Sanofi: Membership on an entity's Board of Directors or advisory committees; Celgene, Janssen, Bluebird Bio, Sutro Biopharma: Research Funding; Poseida: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Nkarta: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees; Teneobio: Consultancy, Membership on an entity's Board of Directors or advisory committees. Qazilbash:Amgen: Consultancy, Other: Advisory Board; Bioclinical: Consultancy; Autolus: Consultancy; Genzyme: Other: Speaker. Kumar:Celgene: Consultancy, Research Funding; Takeda: Research Funding; Janssen: Consultancy, Research Funding. D'Souza:EDO-Mundapharma, Merck, Prothena, Sanofi, TeneoBio: Research Funding; Prothena: Consultancy; Pfizer, Imbrium, Akcea: Membership on an entity's Board of Directors or advisory committees. Hari:BMS: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Amgen: Research Funding; Spectrum: Consultancy, Research Funding; Sanofi: Honoraria, Research Funding; Cell Vault: Equity Ownership; AbbVie: Consultancy, Honoraria.

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A Prospective Study and Identification of Genomewide Association Markers of Familial Predisposition to Plasma Cell Dyscrasias

Blood ◽

10.1182/blood-2020-137337 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 8-8

Author(s):

Adam S Sperling ◽

Rebecca Georgakopoulou ◽

Mehmet Kemal Samur ◽

Christine Ivy Liacos ◽

Brittany E Sandoval ◽

...

Keyword(s):

Genetic Analysis ◽

B Cell ◽

Board Of Directors ◽

Plasma Cell ◽

Monoclonal Gammopathy ◽

Research Funding ◽

Advisory Committees ◽

Familial Predisposition ◽

Plasma Cell Dyscrasias ◽

Second Degree

Introduction: An increased inherited risk for the development of plasma cell dyscrasias (PCDs) has long been suspected, however to date, only a limited number of potential genomic risk loci have been described. To characterize the inherited risk and facilitate identification of additional risk loci it is important to combine detailed pedigrees with extensive genetic analysis. To identify familial PCDs we initiated a prospective study with active recruitment of a large cohort of patients with PCDs and active screening of their relatives combined with tissue banking and subsequent genetic analysis. Methods: All patients in the Department of Clinical Therapeutics diagnosed with PCDs between January 2017 and January 2019, were offered enrollment in the study. Following informed consent, 1st and 2nd degree relatives over the age of 30 were eligible for screening. A detailed family pedigree was created for each index case with special focus on family history of PCDs, B-cell lymphomas, or other hematologic or solid malignancies. As a control, subjects' spouses were also screened. Screening included serum protein electrophoresis with immunofixation. In families where an additional member was identified with a PCD or B-cell malignancy, peripheral blood was collected from consenting family members over the age of 18 for further genetic analysis. Samples from affected individuals were profiled using whole genome sequencing (WGS) and unaffected individuals were genotyped using Axiom Arrays. Data were analyzed using Axion Array Suite and plink and GATK toolkit with BWA. Results: Of 1,084 patients screened for participation in the study; 752 had multiple myeloma (MM), 77 had smoldering MM, 81 a monoclonal gammopathy of undetermined significance, 93 Waldenström's Macroglobulinemia and 81 had AL amyloidosis. 176 (16.2%) patients refused to participate in the study, while 44 (4.1%) patients were ineligible for further screening due to the absence of a living first- or second-degree relative. The median number of screened first or second-degree relatives per index patient was 3 (range 1 to 10). The median age of index cases was 65 years, offspring was 37 years, second-degree relatives was 65 years, and spouses was 65 years. The incidence of a PCD among second-degree relatives was 4.5%, while it was 0.6% among offspring. As a control group, the incidence of PCDs among spouses was 2.6%. Overall at least one additional member (beyond the index patient) with a monoclonal gammopathy was detected in 98 families (11.3%). In 57 families (6.6%) there was a positive history of at least one additional first- or second-degree relative with a PCD or B-cell malignancy. In addition, 41 new cases of monoclonal gammopathy (4.7%) were identified through the screening process associated with this study. To identify genetic loci that could be associated with a predisposition to development of PCDs, genetic analysis was performed on the most heavily affected 18 families, those with at least three affected members or with early onset disease (i.e. PCD diagnosed before age 50). We have evaluated 838,750 SNPs from 103 samples from 18 families. 30 samples were from affected members and 73 from unaffected members. We found eight SNPs (rs13233413, rs11648113, rs59444635, rs148480125, rs113556240, rs11547122, rs671880, rs4726610) that are significantly enriched in affected members with a p-value below the suggestive cut-off of <1e-5. The top candidate was in the untranslated region (UTR) of TSPAN33, a marker of activated and malignant B-cells. We did not detect any significant enrichment in germline mutations in previously reported genes associated with familial PCD risk such as KDM1a, KRAS or DIS3. Functional annotation of the 8 SNPs identified here showed that rs148480125, located in the promoter region of the apoptosis regulator SIVA1, is predicted to impact the allele specific expression level. Further validation work is ongoing. Conclusions: Our active prospective screening approach to identify familial predisposition to PCDs revealed that 11.3% of patients had families with at least one additional affected member and some families had a substantially higher incidence of PCDs with earlier onset. Study of these high-risk families have identified genomewide association markers which in future may help us define familial predisposition to plasma cell dyscrasias. Disclosures Gavriatopoulou: Karyopharm: Consultancy, Honoraria; Genesis Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Terpos:Amgen: Honoraria, Research Funding; Genesis pharma SA: Honoraria, Other: travel expenses , Research Funding; Janssen: Honoraria, Research Funding; Takeda: Honoraria, Other: travel expenses , Research Funding; Celgene: Honoraria; Sanofi: Honoraria; BMS: Honoraria. Kastritis:Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Genesis Pharma: Consultancy, Honoraria. Munshi:Janssen: Consultancy; OncoPep: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; BMS: Consultancy; Legend: Consultancy; Amgen: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy; C4: Current equity holder in private company; Adaptive: Consultancy. Dimopoulos:Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau.

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