The European Myeloma Network (EMN) organized two flow cytometry workshops. The first aimed to identify specific indications for flow cytometry in patients with monoclonal gammopathies, and consensus technical approaches through a questionnaire-based review of current practice in participating laboratories. The second aimed to resolve outstanding technical issues and develop a consensus approach to analysis of plasma cells. The primary clinical applications identified were: differential diagnosis of neoplastic plasma cell disorders from reactive plasmacytosis; identifying risk of progression in patients with MGUS and detecting minimal residual disease. A range of technical recommendations were identified, including: 1) CD38, CD138 and CD45 should all be included in at least one tube for plasma cell identification and enumeration. The primary gate should be based on CD38 vs. CD138 expression; 2) after treatment, clonality assessment is only likely to be informative when combined with immunophenotype to detect abnormal cells. Flow cytometry is suitable for demonstrating a stringent complete remission; 3) for detection of abnormal plasma cells, a minimal panel should include CD19 and CD56. A preferred panel would also include CD20, CD117, CD28 and CD27; 4) discrepancies between the percentage of plasma cells detected by flow cytometry and morphology are primarily related to sample quality and it is, therefore, important to determine that marrow elements are present in follow-up samples, particularly normal plasma cells in MRD negative cases.

myeloma patients showed significantly longer time to progression, higher response rate, and improved survival with single-agent bortezomib versus high-dose dexamethasone. In this updated analysis (median follow-up: 22 months), survival was assessed in both arms, and efficacy updated for the bortezomib arm. Median survival was 29.8 months for bortezomib versus 23.7 months for dexamethasone, a 6-month benefit, despite substantial crossover from dexamethasone to bortezomib. Overall and complete response rates with bortezomib were 43% and 9%, respectively; among responding patients, 56% improved response with longer therapy beyond initial response, leading to continued improvement in overall quality of response. Higher response quality (100% M-protein reduction) was associated with longer response duration; response duration was not associated with time to response. These data confirm the activity of bortezomib and support extended treatment in relapsed multiple myeloma patients tolerating therapy. This study is regis- IntroductionThe international, randomized, phase 3 Assessment of Proteasome Inhibition for Extending Remissions (APEX) trial led to full approval of bortezomib in 2005 for treatment of multiple myeloma (MM) patients who have received at least one prior therapy. In the initial APEX report, single-agent bortezomib demonstrated superior efficacy to high-dose dexamethasone in terms of significantly longer median time to progression (TTP, 6.2 vs 3.5 months, P Ͻ .001), higher response rates (38% vs 18%, P Ͻ .001), and improved survival (1-year survival rate: 80% vs 66%, P ϭ .003; hazard ratio for overall survival [OS]: 0.57, P ϭ .001). 1 As a result, the high-dose dexamethasone arm was halted at interim analysis following the recommendations of an independent data-monitoring committee. A companion crossover study, which offered single-agent bortezomib initially only to patients with progressive disease (PD) on high-dose dexamethasone, was opened to all patients randomized to high-dose dexamethasone.In this updated analysis, we report whether bortezomib continues to provide improved survival compared with high-dose dexamethasone. Other updated efficacy parameters for the bortezomib arm are reported. The relationship between duration of response (DOR) and quality of response as measured by M-protein reduction was analyzed, as was the relationship between DOR and time to first response (TTR). In addition, we report an exploratory analysis comparing patients who initially received bortezomib on APEX with those who first received high-dose dexamethasone and crossed over to receive bortezomib on the companion study. MethodsApproval was obtained from the institutional review boards of all participating institutions (Document S1, available on the Blood website; see the Supplemental Materials link at the top of the online article). For personal use only. on April 29, 2019. by guest www.bloodjournal.org From for five 4-week cycles. Patients were assessed for disease status and survival every 3 weeks for 39 weeks. Fo...

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Treatment in medical oncology is gradually shifting from the use of non-specific chemotherapeutic agents towards an era of novel targeted therapy in which drugs and their combinations target specific aspects of the biology of tumor cells. Multiple myeloma (MM) has become one of the best examples in this regard, reflected in the identification of new pathogenic mechanisms, together with the development of novel drugs that are being explored from the preclinical setting to the early phases of clinical development. We review the biological rationale for the use of the most important new agents for treating MM and summarize their clinical activity in an increasingly busy field. First, we discuss data from already approved and active agents (including second- and third-generation- proteasome inhibitors, immunomodulatory agents (IMIDs) and alkylators). Then we focus on agents with novel mechanisms of action, such as monoclonal antibodies (MoAb), cell cycle specific drugs, deacetylase inhibitors, agents acting on the unfolded protein response, signaling transduction pathway inhibitors, and kinase inhibitors. Among this plethora of new agents or mechanisms some are specially promising: Anti-CD38 MoAb, such as daratumumab, are the first antibodies with clinical activity as single agents in MM. Also the kinesin spindle protein inhibitor Arry-520 is effective in monotherapy as well as in combination with dexamethasone in heavily pretreated patients. Immunotherapy against MM is also being explored, and probably the most attractive example of this approach is the combination of the anti-CS1 MoAb elotuzumab with lenalidomide and dexamethasone, that has produced exciting results in the relapsed/refractory setting.

We have analyzed the applicability, sensitivity and prognostic value of allele-specific oligonucleotide real-time quantitative PCR (ASO RQ-PCR) as a method for minimal residual disease (MRD) assessment in patients with multiple myeloma (MM), comparing the results with those of multiparameter flow cytometry (MFC). A total of 170 patients enrolled in three consecutive Spanish trials achieving at least partial response after treatment were included. Lack of clonality detection (n=31), unsuccessful sequencing (n=17) and suboptimal ASO performance (n=51) limited the applicability of PCR to 42% of cases. MRD was finally investigated in 103 patients (including 32 previously studied) with persistent disease identified by PCR and MFC in 54% and 46% of cases, respectively. A significant correlation in MRD quantitation by both the techniques was noted (r=0.881, P<0.001), being reflective of treatment intensity. Patients with <10(-4) residual tumor cells showed longer progression-free survival (PFS) compared with the rest (not reached (NR) vs 31 months, P=0.002), with similar results observed with MFC. Among complete responders (n=62), PCR discriminated two risk groups with different PFS (49 vs 26 months, P=0.001) and overall survival (NR vs 60 months, P=0.008). Thus, although less applicable than MFC, ASO RQ-PCR is a powerful technique to assess treatment efficacy and risk stratification in MM.

We report on a series of 26 patients diagnosed with primary (de novo) plasma cell (PC) leukemia (PCL) in whom we analyzed the clinicobiologic characteristics of the disease together with the immunophenotype, DNA cell content, proliferative index, and numeric chromosomal aberrations of the neoplastic PC, and compared them with 664 multiple myeloma (MM) patients at diagnosis. The median age, sex ratio, and bone lesion extension were similar, but PCL cases displayed a higher prevalence of clinical stage III, extramedullary involvement, and Bence Jones cases, with fewer IgA cases than for MM patients. In addition, according to several prognostic indicators (β2-microglobulin serum level, proportion of S-phase PCs, proteinuria, calcium serum level, lactate dehydrogenase [LDH] and renal function), the incidence of adverse prognostic factors was significantly higher in PCL versus MM. Immunophenotypic expression was similar for CD38, CD138, CD2, CD3, CD16, CD10, CD13, and CD15, but PCL differed from MM in the expression of CD56, CD9 HLA-DR, CD117, and CD20 antigens. Twenty-two PCL cases were diploid and one was hypodiploid, while most MM cases (57%) showed DNA hyperdiploidy. With the fluorescent in situ hydridization (FISH) technique, 12 of 13 PCL cases displayed the numeric aberrations, −13 (86%), ±1 (57%), +18 (43%), and −X in women (25%), but they lacked several numeric aberrations usually found in MM such as +3, +6, +9, +11, and +15. PCL cases had a lower overall response to therapy than MM cases (38% v 63%, P = .01332). Among PCL patients, a trend for a worse response was observed in cases treated with melphalan and prednisone (MP) versus polychemotherapy. Overall survival was significantly worse in PCL versus MM patients (8 v 36 months,P < .0001), but it was significantly better in PCL patients treated with polychemotherapy versus MP (18 v 3 months,P = .0137). By contrast, MM patients did not show significant differences in overall survival according to the treatment used, MP or polychemotherapy. Ten variables seemed to predict survival in PCL patients, but only the β2-microglobulin level and S-phase PCs retained an independent value in multivariate analysis. In summary, our study illustrates that PCs from PCL display singular phenotypic, DNA cell content, and cytogenetic characteristics that lead to a different disease evolution versus MM.

The aim of the present study was to explore the diagnostic value of the immunophenotypic analysis of bone marrow mast cells (BMMC) in indolent systemic mast cell disease (SMCD) patients. For that purpose, a total of 10 SMCD patients and 19 healthy controls were analyzed. Our results show that BMMC from SMCD are different from normal BMMC with regard to both their light scatter and immunophenotypic characteristics. Accordingly, forward light scatter (FSC), side (90°) light scatter (SSC), and baseline autofluorescence levels were higher in BMMC from indolent SMCD patients than they were in control subjects. From the immunophenotypic point of view, the most striking findings were the constant expression of CD2 (P = .0001), CD25 (P = .0001), and CD35 (P = .06) molecules by BMMC from SMCD patients, markers that were absent from all normal controls. In contrast, CD71, absent in BMMC from indolent SMCD, was positive in BMMC from normal subjects. Although, slight differences between BMMC from SMCD patients and normal controls were found in several other markers, they did not reach statistical significance. In conclusion, our results show that simultaneous assessment of FSC/SSC and reactivity for the CD117, CD2, CD25, CD33, and CD35 forms the basis for the immunophenotypic characterization of BMMC from SMCD in adults and should be integrated with clinical and morphologic studies for the diagnosis of the disease.

We have explored the potential role of genetics in the development of osteonecrosis of the jaw (ONJ) in multiple myeloma (MM) patients under bisphosphonate therapy. A genome-wide association study was performed using 500 568 single nucleotide polymorphisms (SNPs) in 2 series of homogeneously treated MM patients, one with ONJ (22 MM cases) and another without ONJ (65 matched MM controls). Four SNPs (rs1934951, rs1934980, rs1341162, and rs17110453) mapped within the cytochrome P450-2C gene (CYP2C8) showed a different distribution between cases and controls with statistically significant differences (P = 1.07 × 10−6, P = 4.231 × 10−6, P = 6.22 × 10−6, and P = 2.15 × 10−6, respectively). SNP rs1934951 was significantly associated with a higher risk of ONJ development even after Bonferroni correction (P corrected value = .02). Genotyping results displayed an overrepresentation of the T allele in cases compared with controls (48% vs 12%). Thus, individuals homozygous for the T allele had an increased likelihood of developing ONJ (odds ratio 12.75, 95% confidence interval 3.7-43.5).