Prognostic value of high-sensitivity measurable residual disease assessment after front-line chemoimmunotherapy in chronic lymphocytic leukemia.

Measurable residual disease (MRD) status is widely adopted in clinical trials in patients with chronic lymphocytic leukemia (CLL). Findings from FILO group trials (CLL2007FMP, CLL2007SA, CLL2010FMP) enabled investigation of the prognostic value of high-sensitivity (0.7 × 10-5) MRD assessment using flow cytometry, in blood (N = 401) and bone marrow (N = 339), after fludarabine, cyclophosphamide, and rituximab (FCR)-based chemoimmunotherapy in a homogeneous population with long follow-up (median 49.5 months). Addition of low-level positive MRD < 0.01% to MRD ≥ 0.01% increased the proportion of cases with positive MRD in blood by 39% and in bone marrow by 27%. Compared to low-level positive MRD < 0.01%, undetectable MRD was associated with significantly longer progression-free survival (PFS) when using blood (72.2 versus 42.7 months; hazard ratio 0.40, p = 0.0003), but not when using bone marrow. Upon further stratification, positive blood MRD at any level, compared to undetectable blood MRD, was associated with shorter PFS irrespective of clinical complete or partial remission, and a lower 5-year PFS rate irrespective of IGHV-mutated or -unmutated status (all p < 0.05). In conclusion, high-sensitivity (0.0007%) MRD assessment in blood yielded additional prognostic information beyond the current standard sensitivity (0.01%). Our approach provides a model for future determination of the optimal MRD investigative strategy for any regimen.

Standardization of Flow Cytometric Immunophenotyping for Hematological Malignancies: The FranceFlow Group Experience.

Flow cytometry is broadly used for the identification, characterization, and monitoring of hematological malignancies. However, the use of clinical flow cytometry is restricted by its lack of reproducibility across multiple centers. Since 2006, the EuroFlow consortium has been developing a standardized procedure detailing the whole process from instrument settings to data analysis. The FranceFlow group was created in 2010 with the intention to educate participating centers in France about the standardized instrument setting protocol (SOP) developed by the EuroFlow consortium and to organise several rounds of quality controls (QCs) in order to evaluate the feasibility of its application and its results. Here, we report the 5 year experience of the FranceFlow group and the results of the seven QCs of 23 instruments, involving up to 19 centers, in France and in Belgium. The FranceFlow group demonstrates that both the distribution and applicability of the SOP have been successful. Intercenter reproducibility was evaluated using both normal and pathological blood samples. Coefficients of variation (CVs) across the centers were <7% for the percentages of cell subsets and <30% for the median fluorescence intensities (MFIs) of the markers tested. Intracenter reproducibility provided similar results with CVs of <3% for the percentages of the majority of cell subsets, and CVs of <20% for the MFI values for the majority of markers. Altogether, the FranceFlow group show that the 19 participating labs might be considered as one unique laboratory with 23 identical flow cytometers able to reproduce identical results. Therefore, SOP significantly improves reproducibility of clinical flow in hematology and opens new avenues by providing a robust companion diagnostic tool for clinical trials in hematology. © 2019 International Society for Advancement of Cytometry.

FLT3 ligand plasma levels have no impact on outcomes after allotransplant in acute leukemia.

OBJECTIVE: This study was designed to assess the impact on outcomes of early soluble Fms-like tyrosine kinase 3 ligand concentrations (sFLc) in patients receiving an allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). METHODS: This was a prospective monocentric study including all allo-HSCT patients included in the previous FLAM/FLAL study (Peterlin et al., 2019). Blood samples collected before the start of conditioning then post-transplant were frozen, stored and tested by ELISA. The parameters considered were hematopoietic recoveries, Leukemia Free Survival and Overall Survival, acute and chronic GVHD, grade 3 or 4 acute and/or extensive chronic GVHD-free and relapse-free survival (GRFS). RESULTS: Forty-one patients were included, a total of 179 samples were assayed for sFLc. There was no impact of sFLc levels (<=median vs> median) on acute and chronic GVHD incidences, LFS, OS nor GRFS. CONCLUSION: At variance with induction results for AML (Peterlin et al., 2019) endogenous sFLc do not appear to be a prognostic marker at the time of or after allo-HSCT. Even though the results are negatives, this is, to the best of our knowledge, the only prospective series specifically addressing the question of sFLc impact after allo-HSCT in acute leukemias.

Minimal residual disease negativity using deep sequencing is a major prognostic factor in multiple myeloma.

The introduction of novel agents has led to major improvements in clinical outcomes for patients with multiple myeloma. To shorten evaluation times for new treatments, health agencies are currently examining minimal residual disease (MRD) as a surrogate end point in clinical trials. We assessed the prognostic value of MRD, measured during maintenance therapy by next-generation sequencing (NGS). MRD negativity was defined as the absence of tumor plasma cell within 1 000 000 bone marrow cells (<10-6). Data were analyzed from a recent clinical trial that evaluated the role of transplantation in newly diagnosed myeloma patients treated with lenalidomide, bortezomib, and dexamethasone (RVD). MRD negativity was achieved at least once during maintenance in 127 patients (25%). At the start of maintenance therapy, MRD was a strong prognostic factor for both progression-free survival (adjusted hazard ratio, 0.22; 95% confidence interval, 0.15-0.34; P < .001) and overall survival (adjusted hazard ratio, 0.24; 95% confidence interval, 0.11-0.54; P = .001). Patients who were MRD negative had a higher probability of prolonged progression-free survival than patients with detectable residual disease, regardless of treatment group (RVD vs transplant), cytogenetic risk profile, or International Staging System disease stage at diagnosis. These results were similar after completion of maintenance therapy. Our findings confirm the value of MRD status, as determined by NGS, as a prognostic biomarker in multiple myeloma, and suggest that this approach could be used to adapt treatment strategies in future clinical trials.

Major impact of an early bone marrow checkpoint (day 21) for minimal residual disease in flow cytometry in childhood acute lymphoblastic leukemia.

The early persistence of minimal residual disease (MRD) is considered a poor prognostic factor indicative of chemoresistance in acute lymphoblastic leukemia. In French children, chemosensitivity is assessed at day 21 post-induction by cytomorphology. Here, it was investigated whether a more precise evaluation could be obtained at this time point with multiparameter flow cytometry (MFC). This study enrolled 123 children with de novo acute lymphoblastic leukemia. MRD0 was investigated at day 21 in MFC with a combination of antibodies based on the immunophenotype of diagnosis. It was also evaluated at day 35 by immunoglobulin/T-cell receptor quantitative real-time polymerase chain reaction (MRD1). Three risk groups could be delineated based on MRD0. Patients with MFC/MRD0 levels >10-2 (n = 25) were considered high risk, those with levels between 10-2 and 10-4 (n = 46) intermediate risk, and those <10-4 (n = 50) low risk. Overall survival (p = 0.048) and event-free survival (EFS, p = 0.00017) were significantly different between these three groups. EFS of the 14 corticoresistant patients strongly depended on their MRD0 level (p = 0.004). Similarly, both EFS (p = 0.0004) and overall survival (p = 0.02) were significantly different in the 109 chemosensitive patients, according to MRD0 levels. MRD0 and MRD1 levels, compared with 112 patients, were consistent (-/- or +/+) in 57.2% of the cases. Both MRD0+/MRD1+ and MRD0+/MRD1- patients had a significantly worse EFS (p = 0.0001) than those with undetectable MRD at both MRD0 and MRD1. This study confirms the usefulness and superiority of an early point of MRD detection by MFC. In addition, MRD0 in MFC identifies a subgroup of patients with poorer prognosis (MRD0+/MRD1-). Copyright © 2015 John Wiley & Sons, Ltd.

CD180 expression in B-cell lymphomas: A multicenter GEIL study.

CD180, a related member of the Toll-like receptor family, is lost or underexpressed at the plasma membrane in circulating cells of various B-cell lymphomas except marginal zone lymphomas (MZL). In order to confirm its clinical relevance in routine analysis, we evaluated prospectively the expression of CD180 in 236 patients from 5 French University Hospital laboratories on behalf of the GEIL. Highly comparable results were obtained in all centers using the EuroFlow standardization protocol. We observed that CD180 median fluorescence (MdFI) was significantly higher in MZL and hairy cell leukaemia (HCL) compared to all other B-cell proliferations (P < 0.05). CD180 intensity could distinguish lymphomas with numerous villous lymphocytes from other MZL. ROC curve analysis identified a CD180 MdFI threshold for which the diagnosis of MZL could be assessed with 77% sensitivity and 92% specificity. This study showed that CD180 can be considered as a single positive robust marker of MZL and should be therefore included in flow cytometry panels for the diagnosis of mature B-cell neoplasms. Harmonization process is of great interest in order to evaluate new markers in multicentric studies and to set up decisional thresholds. © 2015 International Clinical Cytometry Society.

(90)Y-labelled anti-CD22 epratuzumab tetraxetan in adults with refractory or relapsed CD22-positive B-cell acute lymphoblastic leukaemia: a phase 1 dose-escalation study.

BACKGROUND: Prognosis of patients with relapsed or refractory acute lymphoblastic leukaemia is poor and new treatments are needed. We aimed to assess the feasibility, tolerability, dosimetry, and efficacy of yttrium-90-labelled anti-CD22 epratuzumab tetraxetan ((90)Y-DOTA-epratuzumab) radioimmunotherapy in refractory or relapsed CD22-positive B-cell acute lymphoblastic leukaemia in a standard 3 + 3 phase 1 study. METHODS: Adults (≥18 years) with relapsed or refractory B-cell acute lymphoblastic leukaemia (with CD22 expression on at least 70% of blast cells) were enrolled at six centres in France. Patients received one cycle of (90)Y-DOTA-epratuzumab on days 1 and 8 (give or take 2 days) successively at one of four dose levels: 2·5 mCi/m(2) (92·5 MBq/m(2); level 1), 5·0 mCi/m(2) (185 MBq/m(2); level 2), 7·5 mCi/m(2) (277·5 MBq/m(2); level 3), and 10·0 mCi/m(2) (370 MBq/m(2); level 4). The primary objective was to identify the maximum tolerated dose of (90)Y-DOTA-epratuzumab. We assessed safety during infusions and regularly after radioimmunotherapy over a 6-month period. Analyses included only patients who received radioimmunotherapy. The trial is closed to inclusion and is registered at ClinicalTrials.gov, NCT01354457. FINDINGS: Between Aug 25, 2011, and June 11, 2014, 17 patients (median age 62 years; range 27-77) were treated (five at level 1, three at level 2, three at level 3, and six at level 4). Radioimmunotherapy infusion was overall well tolerated. One dose-limiting toxic effect (aplasia lasting 8 weeks) occurred at level 4, but the maximum tolerated dose was not reached. The most common grade 3-4 adverse events were pancytopenia (one patient at level 2, one at level 3, and six at level 4) and infections (three at level 1, one at level 2, and five at level 4). INTERPRETATION: (90)Y-DOTA-epratuzumab radioimmunotherapy is well tolerated. We recommend the dose of 2 × 10·0 mCi/m(2) 1 week apart per cycle for phase 2 studies. FUNDING: Immunomedics and Direction de la Recherche Clinique of Nantes.

Methodological aspects of minimal residual disease assessment by flow cytometry in acute lymphoblastic leukemia: A French multicenter study.

BACKGROUND: Minimal residual disease (MRD) assessment provides a powerful prognostic factor for therapeutic stratification in acute lymphoblastic leukemia (ALL). Multiparameter flow cytometry (MFC) has the potential for a rapid and sensitive identification of high risk patients. Our group has previously published that MRD levels analyzed by clone specific Ig/TcR-QPCR and MFC were concordant at a sensitivity of 10(-4) . Here we report the MFC methodological aspects from this multi-center experience. METHODS: MRD was assessed by MFC in 1030 follow-up samples from 265 pediatric and adult patients with de novo ALL treated in the FRALLE, EORTC, or GRALL clinical trials. MRD assessment as applied by the eight participating MFC laboratories is described in detail regarding cell preparation, leukemia-associated immunophenotype (LAIP) markers and data analysis. Samples were obtained from bone marrow (BM) and peripheral blood (PB). Immunostaining was performed after erythrocyte lysis or Ficoll enrichment. RESULTS: This study confirms the applicability of MFC-based MRD assessment in 97% of patients with ALL at the 10(-4) cut-off. MRD values after Ficoll enrichment and erythrocyte lysis were found comparable. Higher MRD values were obtained in BM than in PB, especially for B-lineage ALL. CONCLUSIONS: Measurement of MRD by MFC at the 10(-4) cut-off is applicable within a few hours for almost all patients and using a comparable analytical strategy allows for multicenter collaborative studies. The method can be introduced in a strategy aimed at defining the risk of failure of patients with childhood or adult ALL.

Front-line transplantation program with lenalidomide, bortezomib, and dexamethasone combination as induction and consolidation followed by lenalidomide maintenance in patients with multiple myeloma: a phase II study by the Intergroupe Francophone du Myélome.

PURPOSE: The three-drug combination of lenalidomide, bortezomib, and dexamethasone (RVD) has shown significant efficacy in multiple myeloma (MM). The Intergroupe Francophone du Myélome (IFM) decided to evaluate RVD induction and consolidation therapies in a sequential intensive strategy for previously untreated transplantation-eligible patients with MM. PATIENTS AND METHODS: In this phase II study, 31 symptomatic patients age < 65 years were enrolled to receive three RVD induction cycles followed by cyclophosphamide harvest and transplantation. Patients subsequently received two RVD consolidation cycles and 1-year lenalidomide maintenance. RESULTS: Very good partial response rate or better at the completion of induction, transplantation, and consolidation therapy was 58%, 70%, and 87%, respectively. Maintenance upgraded responses in 27% of patients. Overall, 58% of patients achieved complete response, and 68% were minimal residual disease (MRD) negative by flow cytometry. The most common toxicities with RVD were neurologic and hematologic, including grade 1 to 2 sensory neuropathy (55%), grade 3 to 4 neutropenia (35%), and thrombocytopenia (13%). Two basal cell carcinomas in the same patient and one case of breast cancer were observed. There was no treatment-related mortality. With a median follow-up of 39 months, estimated 3-year progression-free and overall survival were 77% and 100%, respectively. None of the patients who achieved MRD negativity relapsed. CONCLUSION: The transplantation program with RVD induction and consolidation followed by lenalidomide maintenance produced high-quality responses and showed favorable tolerability in patients with newly diagnosed MM. Overall, 68% of patients achieved MRD negativity; none of these patients relapsed. This program is being evaluated in the ongoing IFM/Dana-Farber Cancer Institute 2009 phase III study.

Immunophenotype of normal and myelomatous plasma-cell subsets.

Plasma cells (PCs) are essentially characterized by the co-expression of CD138 and CD38, which allows their identification in flow cytometry in bone marrow (BM), peripheral blood, or cell suspensions from tissues. These terminally differentiated B-cells may lose the expression of surface CD19 and that of CD20 while retaining CD27. When malignant, they can gain a number of other markers such as CD28, CD33, CD56, or CD117 and lose CD27. Moreover, since each PC is only able to produce a single type of immunoglobulins (Igs), they display isotypic restriction and clonal malignant PCs can be further characterized by their homogeneous expression of either kappa or lambda light chains. In multiple myeloma (MM), such PC clones produce the Ig identified in plasma as an abnormal peak. In the BM where they essentially accumulate, these PCs may however display various immunophenotypes. The latter were explored in a two-way approach. Firstly, the various subsets delineated by the selective or common expression of CD19 together with combined CD56/CD28 were explored in normal and MM BM. Then, other aberrant markers' expression was investigated, i.e., CD20, CD27, CD33, CD56, CD117. These data were compared to literature information. They underline the vast heterogeneity of MM PCs possibly accounting for the various answers to therapy of MM patients.

BCR-ABL1 molecular remission after 90Y-epratuzumab tetraxetan radioimmunotherapy in CD22+ Ph+ B-ALL: proof of principle.

Although targeted therapies are used increasingly in hematologic malignancies, we are unaware of any prior studies of radioimmunotherapy (RAIT) in B-acute lymphoblastic leukemia (ALL), even though this radiosensitive tumor expresses CD22, potentially a good target for this approach. Here, we report a patient with Philadelphia chromosome-positive B-ALL in third relapse who received RAIT with (90) yttrium ((90) Y)-labeled anti-CD22 epratuzumab tetraxetan. Seven weeks after initiating therapy, the patient achieved a BCR-ABL1 molecular remission documented by RT-qPCR, which is now continuing at 6 months while awaiting an allogeneic hematopoietic stem cell transplant. (90) Y-Epratuzumab tetraxetan may be a promising therapeutic option for CD22(+) B-ALL patients.

Characterization of various blood and graft sources: a prospective series.

BACKGROUND: Studies comparing cell components of blood and graft sources are very scarce. We present here a thorough study examining the cellular content of various sources of blood and cell therapy products. STUDY DESIGN AND METHODS: We have prospectively compared by fluorescence-activated cell sorting analyses the cellular composition of three blood sources on the one hand--peripheral blood (PB; n = 10) versus granulocyte-colony-stimulating factor (G-CSF)-mobilized PB (GCSF-PB, n = 10) versus cord blood (CB, n = 10)--and of three graft sources on the other hand--unmanipulated bone marrow (uBM, n = 5) versus leukapheresis product (LP, n = 10) versus thawed CB graft (n = 7). RESULTS: All median absolute numbers of cell subsets were found significantly higher in GCSF-PB and LP, except for monocytoid dendritic cells (mDCs) in CB and uBM. The most impressive results were the median quantities of memory T and B lymphocytes but also of plasmacytoid DCs (pDCs) contained in LP compared to thawed CB graft, with ratios of 375, 318, and 247, respectively. The proportions of naive and CD4+/CD8- T cells, transitional B cells, and CD5+ and naive B lymphocytes were found significantly higher in CB samples while the proportions of mDCs and pDCs were found significantly lower. CONCLUSION: Our study shows strong differences in terms of quantitative and qualitative cellular composition between several blood or graft sources, possibly explaining the differences observed in terms of outcomes after transplant.