Report of the European Myeloma Network on multiparametric flow cytometry in multiple myeloma and related disorders

This is an open access paper.-- et al.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.The meetings were sponsored by the European Myeloma.Peer Reviewe

Minimal residual disease is an independent predictor for 10-year survival in CLL

Minimal residual disease (MRD) negativity, defined as <1 chronic lymphocytic leukemia (CLL) cell detectable per 10 000 leukocytes, has been shown to independently predict for clinical outcome in patients receiving combination chemoimmunotherapy in the frontline setting. However, the long-term prognostic value of MRD status in other therapeutic settings remains unclear. Here, we retrospectively analyzed, with up to 18 years follow-up, all patients at our institution who achieved at least a partial response (PR) with various therapies between 1996 and 2007, and received a bone marrow MRD assessment at the end of treatment according to the international harmonized approach. MRD negativity correlated with both progression-free survival (PFS) and overall survival (OS) independent of the type and line of treatment, as well as known prognostic factors including adverse cytogenetics. The greatest impact of achieving MRD negativity was seen in patients receiving frontline treatment, with 10-year PFS of 65% vs 10% and 10-year OS of 70% vs 30% for MRD-negative vs MRD-positive patients, respectively. Our results demonstrate the long-term benefit of achieving MRD negativity, regardless of the therapeutic setting and treatment modality, and support its use as a prognostic marker for long-term PFS and as a potential therapeutic goal in CLL

GA101 (obinutuzumab) monocLonal Antibody as Consolidation Therapy In CLL (GALACTIC) trial: study protocol for a phase II/III randomised controlled trial

Background: Chronic lymphocytic leukaemia (CLL) is the most common adult leukaemia. Achieving minimal residual disease (MRD) negativity in CLL is an independent predictor of survival even with a variety of different treatment approaches and regardless of the line of therapy. Methods/design: GA101 (obinutuzumab) monocLonal Antibody as Consolidation Therapy In CLL (GALACTIC) is a seamless phase II/III, multi-centre, randomised, controlled, open, parallel-group trial for patients with CLL who have recently responded to chemotherapy. Participants will be randomised to receive either obinutuzumab (GA-101) consolidation or no treatment (as is standard). The phase II trial will assess safety and short-term efficacy in order to advise on continuation to a phase III trial. The primary objective for phase III is to assess the effect of consolidation therapy on progression-free survival (PFS). One hundred eighty-eight participants are planned to be recruited from forty research centres in the United Kingdom. Discussion: There is evidence that achieving MRD eradication with alemtuzumab consolidation is associated with improvements in survival and time to progression. This trial will assess whether obinutuzumab is safe in a consolidation setting and effective at eradicating MRD and improving PFS. Trial registration: ISRCTN, 64035629. Registered on 12 January 2015. EudraCT, 2014-000880-42. Registered on 12 November 2014

Assessment of ibrutinib plus rituximab in front-line CLL (FLAIR trial): study protocol for a phase III randomised controlled trial

Background Treatment of chronic lymphocytic leukaemia (CLL) has seen a substantial improvement over the last few years. Combination immunochemotherapy, such as fludarabine, cyclophosphamide and rituximab (FCR), is now standard first-line therapy. However, the majority of patients relapse and require further therapy, and so new, effective, targeted therapies that improve remission rates, reduce relapses, and have fewer side effects, are required. The FLAIR trial will assess whether ibrutinib plus rituximab (IR) is superior to FCR in terms of progression-free survival (PFS). Methods/design FLAIR is a phase III, multicentre, randomised, controlled, open, parallel-group trial in patients with previously untreated CLL. A total of 754 participants will be randomised on a 1:1 basis to receive standard therapy with FCR or IR. Participants randomised to FCR will receive a maximum of six 28-day treatment cycles. Participants randomised to IR will receive six 28-day cycles of rituximab, and ibrutinib taken daily for 6 years until minimal residual disease (MRD) negativity has been recorded for the same amount of time as it took to become MRD negative, or until disease progression. The primary endpoint is PFS according to the International Workshop on CLL (IWCLL) criteria. Secondary endpoints include: overall survival; proportion of participants with undetectable MRD; response to therapy by IWCLL criteria; safety and toxicity; health-related quality of life (QoL); and cost-effectiveness. Discussion The trial aims to provide evidence for the future first-line treatment of CLL patients by assessing whether IR is superior to FCR in terms of PFS, and whether toxicity rates are favourable. Trial registration ISRCTN01844152. Registered on 8 August 2014, EudraCT number 2013-001944-76. Registered on 26 April 2013

Ibrutinib Plus Venetoclax in Relapsed/Refractory Chronic Lymphocytic Leukemia: The CLARITY Study.

PURPOSE:The treatment of chronic lymphocytic leukemia (CLL) has been revolutionized by targeted therapies that either inhibit proliferation (ibrutinib) or reactivate apoptosis (venetoclax). Both significantly improve survival in CLL and replace chemoimmunotherapy for many patients. However, individually, they rarely lead to eradication of measurable residual disease (MRD) and usually are taken indefinitely or until progression. We present the CLARITY trial that combined ibrutinib with venetoclax to eradicate detectable CLL with the intention of stopping therapy. PATIENTS AND METHODS:CLARITY is a phase II trial that combined ibrutinib with venetoclax in patients with relapsed or refractory CLL. The primary end point was eradication of MRD after 12 months of combined therapy. Key secondary end points were response by International Workshop on CLL criteria, safety, and progression-free and overall survival. RESULTS:In 53 patients after 12 months of ibrutinib plus venetoclax, MRD negativity (fewer than one CLL cell in 10,000 leukocytes) was achieved in the blood of 28 (53%) and the marrow of 19 (36%). Forty-seven patients (89%) responded, and 27 (51%) achieved a complete remission. After a median follow-up of 21.1 months, one patient progressed, and all patients were alive. A single case of biochemical tumor lysis syndrome was observed. Other adverse effects were mild and/or manageable and most commonly were neutropenia or GI events. CONCLUSION:The combination of ibrutinib plus venetoclax was well tolerated in patients with relapsed or refractory CLL. There was a high rate of MRD eradication that led to the cessation of therapy in some patients. The progression-free and overall survival rates are encouraging for relapsed and refractory CLL

Different biology and clinical outcome according to the absolute numbers of clonal B-cells in monoclonal B-cell lymphocytosis (MBL)

The biological and clinical relationship between Chronic Lymphocytic Leukaemia (CLL) and Monoclonal B-cell Lymphocytosis (MBL) has now been reported in some detail. This review investigates associations between biology and disease activity as they relate to the absolute numbers of abnormal cells. The clonal B-cells in CLL-type MBL are indistinguishable from CLL with respect to surface phenotype and the presence of chromosomal abnormalities. However, the majority of CLL-type MBL cases in the general population have very low numbers of clonal B-cells, typically in the range 0.1-10 per μL, and such cases use different IGHV genes than higher-count CLL-type MBL cases and often show intraclonal heterogeneity. Cases with higher counts are biologically similar to CLL although there is a relationship between the CLL cell count at presentation and the likelihood of further clonal expansion. Individuals presenting with CLL cell counts above 2,000 per μL are more likely to have gradually increasing B-cell counts over time and although the risk of requiring treatment for progressive CLL remains low there may be impaired normal B-cell activity. © 2010 International Clinical Cytometry Society.Grant sponsors: Leukaemia and Lymphoma Research (www. beatbloodcancers.org) (to AR and PH); NCI; Grant number: 5K23CA113408 (to TS); Grant sponsors: Bernstein Family Fund for Leukemia Research (to ML); AIRC-Milano; Fondazione Cariplo; Prin-Muir and Fondazione Anna Villa e Felice Rusconi-Varese (to PG).Peer Reviewe

Highly sensitive b cell analysis predicts response to rituximab therapy in rheumatoid arthritis

Objective. In rheumatoid arthritis (RA), B cell depletion occurs in all patients treated with rituximab, but the clinical responses to rituximab are variable. A highly sensitive assay was used to test the hypothesis that B cell depletion is variable, and that incomplete depletion leads to a poorer outcome. Methods. Sixty patients with active RA unresponsive to anti-tumor necrosis factor agents received two I-gram infusions of rituximab. B cell numbers were measured by highly sensitive flow cytometry before and after each infusion and at 3-month intervals thereafter. A reduction in B cell levels below 0.0001 x 10(9)/liter was defined as complete depletion (compared with 0.05 x 109/liter by conventional cytometry). Clinical responses were measured using the European League Against Rheumatism (EULAR) criteria. Results. At 6 months, 92% of patients had a moderate-to-good clinical response according to the EULAR criteria. B cells were detected in 63% of patients after the first infusion of rituximab (median level 0.0009 x 10(9)/liter [range &amp;lt;0.0001-0.0015 x 10(9)/liter), and these patients had poorer clinical outcomes than patients with complete depletion. At 9 months, 82% of patients with complete depletion had a moderate-to-good EULAR response, compared with 43% of those with partial depletion (P = 0.01). At 12 months, 59% of complete responders had a moderate-to-good EULAR response, compared with 21% of those with partial depletion (P = 0.01). Patients in whom B cells were depleted only after the second infusion did no better than those in whom depletion was never complete and had poorer clinical outcomes than those in whom depletion was initially complete. Conclusion. This study is the first to show, using a highly sensitive analysis, that rituximab therapy is associated with variable diminution in B cell numbers. A lack of complete depletion of B cells after I infusion was associated with a poorer outcome

Human peripheral blood B-Cell compartments: A crossroad in B-cell traffic

A relatively high number of different subsets of B-cells are generated through the differentiation of early B-cell precursors into mature B-lymphocytes in the bone marrow (BM) and antigen-triggered maturation of germinal center B-cells into memory B-lymphocytes and plasmablasts in lymphoid tissues. These B-cell subpopulations, which are produced in the BM and lymphoid tissues, recirculate through peripheral blood (PB), into different tissues including mucosa and the BM, where long-living plasma cells produce antibodies. These circulating PB B-cells can be classified according to their maturation stage into i) immature/transitional, ii) na?̈ve, and iii) memory B-lymphocytes, and iv) plasmablasts/plasma cells. Additionally, unique subsets of memory B-lymphocytes and plasmablasts/plasma cells can be identified based on their differential expression of unique Ig-heavy chain isotypes (e.g.: IgM, IgD, IgG, IgA). In the present paper, we review recent data reported in the literature about the distribution, immunophenotypic and functional characteristics of these cell subpopulations, as well as their distribution in PB according to age and seasonal changes. Additional information is also provided in this regard based on the study of a population-based cohort of 600 healthy adults aged from 20 to 80 years, recruited in the Salamanca area in western Spain. Detailed knowledge of the distribution and traffic of B-cell subsets through PB mirrors the immune status of an individual subject and it may also contribute to a better understanding of B-cell disorders related to B-cell biology and homeostasis, such as monoclonal B-cell lymphocytosis (MBL). © 2010 International Clinical Cytometry Society.Grant sponsor: MSCNet European strep; Grant number: N_ E06005FF; Grant sponsor: Fondo de Investigación Sanitaria, Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo, Madrid, Spain; Grant numbers: RTICC RD06/0020/0035, PI06/0824, PS09/02430; Grant sponsor: Gerencia Regional de Salud de castilla y León; Grant number: GRS206/A/08; Grant sponsor: Ayuda GR37 de Excelencia de Castilla y León, Consejeria de Educación, Junta de Castilla y León, Valladolid, Spain; Fundación Samuél Solorzano, Salamanca, Spain; Grant number: FS/16-2008.Peer Reviewe