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Abstract Monoclonal gammopathy of undetermined significance (MGUS) is the earliest discernible stage of multiple myeloma (MM) and Waldenström’s macroglobulinemia (WM). Early diagnosis of MG may be compromised by the low-level infiltration, undetectable to low-sensitive methodologies. Here, we investigated the prevalence and immunophenotypic profile of clonal (c) plasma cells (PC) and/or cB-lymphocytes in bone marrow (BM) and blood of subjects with a serum M-component from the iSTOPMM program, using high-sensitive next-generation flow cytometry (NGF), and its utility in the diagnostic classification of early-stage MG. We studied 164 paired BM and blood samples from 82 subjects, focusing the analysis on: 55 MGUS, 12 smoldering MM (SMM) and 8 smoldering WM (SWM). cPC were detected in 84% of the BM samples and cB-lymphocytes in 45%, coexisting in 39% of cases. In 29% of patients, the phenotypic features of cPC and/or cB-lymphocytes allowed a more accurate disease classification, including: 19/55 (35%) MGUS, 1/12 (8%) SMM and 2/8 (25%) SWM. Blood samples were informative in 49% of the BM-positive cases. We demonstrated the utility of NGF for a more accurate diagnostic classification of early-stage MG.

This multicentre, phase II study of the Australian Lymphoma and Leukaemia Group (ALLG) and the Asian Myeloma Network (AMN) investigated fixed-duration (18-month) treatment with carfilzomib (K), thalidomide (T), and dexamethasone (d; KTd) in patients with relapsed and/or refractory multiple myeloma and 1-3 prior lines of therapy. Patients received induction with up to twelve 28-day cycles of K [20mg/m2 IV cycle 1 day 1 and 2, 56mg/m2 (36mg/m2 for patients ≥75 years) from day 8 onwards), T 100mg PO nocte and weekly dexamethasone 40mg (20mg for patients ≥75 years). During maintenance T was omitted, while K continued on days 1,2,15,16 with fortnightly dexamethasone. The primary endpoint was progression free survival (PFS). Secondary endpoints were overall response rate, overall survival (OS), duration of response, safety, and tolerability. Ninety-three patients (median age 66.3 years (41.9 – 84.5)) were enrolled with a median follow-up of 26.4 (1.6 – 54.6) months. The median PFS was 22.3 months (95% CI 15.7 – 25.6) with a 46.3% (95% CI 35.1 – 52.8) 2-year PFS. Median OS was not reached and was 73.8% (95% CI 62.9 – 81.9) at 2 years. The overall response rate was 88% (≥ VGPR 73%). There was no difference in the depth of response, PFS or OS comparing Asian and Non-Asian cohorts (p=0.61). The safety profile for KTd was consistent with each individual drug. KTd is well tolerated and effective in patients with RRMM irrespective of Asian or non-Asian ethnicity and provides an alternative option particularly where use of KRd is limited by access, cost, or renal impairment.

Abstract Primary plasma cell leukemia (PCL) has a consistently ominous prognosis, even after progress in the last decades. PCL deserves a prompt identification to start the most effective treatment for this ultra-high-risk disease. The aim of this position paper is to revisit the diagnosis of PCL according to the presence of circulating plasma cells in patients otherwise meeting diagnostic criteria of multiple myeloma. We could identify two retrospective series where the question about what number of circulating plasma cells in peripheral blood should be used for defining PCL. The presence of ≥5% circulating plasma cells in patients with MM had a similar adverse prognostic impact as the previously defined PCL. Therefore, PCL should be defined by the presence of 5% or more circulating plasma cells in peripheral blood smears in patients otherwise diagnosed with symptomatic multiple myeloma.

Abstract Plasma cell disorders (PCDs) are identified in the clinical lab by detecting the monoclonal immunoglobulin (M-protein) which they produce. Traditionally, serum protein electrophoresis methods have been utilized to detect and isotype M-proteins. Increasing demands to detect low-level disease and new therapeutic monoclonal immunoglobulin treatments have stretched the electrophoretic methods to their analytical limits. Newer techniques based on mass spectrometry (MS) are emerging which have improved clinical and analytical performance. MS is gaining traction into clinical laboratories, and has replaced immunofixation electrophoresis (IFE) in routine practice at one institution. The International Myeloma Working Group (IMWG) Mass Spectrometry Committee reviewed the literature in order to summarize current data and to make recommendations regarding the role of mass spectrometric methods in diagnosing and monitoring patients with myeloma and related disorders. Current literature demonstrates that immune-enrichment of immunoglobulins coupled to intact light chain MALDI-TOF MS has clinical characteristics equivalent in performance to IFE with added benefits of detecting additional risk factors for PCDs, differentiating M-protein from therapeutic antibodies, and is a suitable replacement for IFE for diagnosing and monitoring multiple myeloma and related PCDs. In this paper we discuss the IMWG recommendations for the use of MS in PCDs.

Multiple myeloma (MM) is a plasma cell malignancy whereby a single clone of plasma cells over-propagates in the bone marrow, resulting in the increased production of monoclonal immunoglobulin. While the complex genetic architecture of MM is well characterized, much less is known about germline variants predisposing to MM. Genome-wide sequencing approaches in MM families have started to identify rare high-penetrance coding risk alleles. In addition, genome-wide association studies have discovered several common low-penetrance risk alleles, which are mainly located in the non-coding genome. Here, we further explored the genetic basis in familial MM within the non-coding genome in whole-genome sequencing data. We prioritized and characterized 150 upstream, 5′ untranslated region (UTR) and 3′ UTR variants from 14 MM families, including 20 top-scoring variants. These variants confirmed previously implicated biological pathways in MM development. Most importantly, protein network and pathway enrichment analyses also identified 10 genes involved in mitogen-activated protein kinase (MAPK) signaling pathways, which have previously been established as important MM pathways.