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We evaluated the impact of detection of minimal residual disease by flow cytometry (FCMRD) and CD3 chimerism in relapse in a cohort of 87 patients with acute myeloid leukemia or myelodysplastic syndrome undergoing stem cell transplantation. Patients with a positive FCMRD at day +100 after transplantation showed higher relapse rates and worse overall survival. In multivariate analysis, a positive FCMRD after transplantation was a significant predictor of relapse. Mixed chimerism showed a trend to statistical signification. We conclude that FCMRD at day 100 after SCT is the best predictor of relapse after SCT in patients with aggressive myeloid malignancies.

Background: CC-90009 is a novel cereblon E3 ligase modulator (CELMoD), which is currently under investigation in a first-in-human, phase I study (CC-90009-AML-001; NCT02848001) in patients with R/R AML. In preclinical models, CC-90009 drives the binding of the target protein, translation termination factor G1 to S phase transition 1 (GSPT1), to cereblon and induces its ubiquitination and proteasome-dependent degradation. Loss of GSPT1 results in activation of the integrated stress response (ISR), inhibition of nonsense-mediated decay (NMD), and induction of apoptosis. Deep degradation of GSPT1, mediated by CC-90009, led to AML cell death in vitro and potent antitumor activity in patient-derived AML xenograft models. In the ongoing phase I study, CC-90009 has demonstrated antileukemic activity. Here, we characterize the pharmacodynamic responses using a suite of novel assays to support CC-90009 dose and schedule optimization. Methods: Adult patients with R/R AML received intravenous CC-90009 daily on Days 1-5 (D1-5 schedule) or on Days 1-3 and 8-10 (D1-3/8-10 schedule) of a 28-day cycle. Peripheral blood samples taken before, during, and after dosing in the first treatment cycle were analyzed. Levels of intracellular GSPT1 in blasts and normal blood cell types were quantitated by flow cytometry analysis. Transcript levels of ISR and NMD variants in peripheral blood mononuclear cells (PBMC) were measured by qPCR. Bone marrow (BM) core biopsies at screening, Cycle 1 Day 5 and 28, and Cycle 2 and 4 Day 28, were analyzed for GSPT1, cleaved caspase 3, and CD34 protein expression by immunohistochemistry. ATF3 and DDIT3 mRNA levels were assessed in BM samples by RNA in situ hybridization. Results: The rate and depth of GSPT1 loss in T cells and in circulating AML blasts increased with dose. A marked reduction in GSPT1 was observed in T cells and blast cells of most patients after the first dose of CC-90009 at all dose levels, and GSPT1 levels approached the assay floor between Days 2 and 5 at doses of 1.2 mg and higher on the D1-5 schedule. At 2.4 mg and higher on the D1-5 schedule, a reduction in GSPT1 levels of > 90% was observed in T cells (19 of 29 patients) and in blast cells (11 of 29 patients), with stronger GSPT1 reductions detected in AML blasts and normal T cells compared with B cells or granulocytes. In the 3 mg D1-5 cohort, patients with sustained GSPT1 reduction in peripheral blasts in the days following treatment had more persistent blast suppression compared with patients showing an earlier rebound of GSPT1. At 3 mg and 3.6 mg dose levels, continuous treatment (D1-5) resulted in slower kinetics of GSPT1 rebound and conferred superior antileukemic activity compared with the intermittent dosing schedule (D1-3/D8-10). In addition to measuring the direct target of CC-90009, GSPT1, we also investigated markers downstream of GSPT1 degradation. Several patients with deep and sustained GSPT1 loss in the high-dose cohorts (2.4 mg and above) showed increased levels of ISR-related transcripts (ATF3 and DDIT3) and NMD-associated splice variants (SRSF3 and SRSF6) in on-treatment PBMC samples. Similarly, in BM, deep GSPT1 loss coincided with induction of ATF3 and DDIT3 mRNA, increased cleaved caspase 3 expression, and reduced CD34+ blasts. These clinical findings are consistent with our preclinical studies in which GSPT1 loss culminated in apoptosis, which may be mediated through activation of ISR and inhibition of NMD pathways. Conclusions: CC-90009 is a novel CELMoD and a first-in-class GSPT1 degrader. A suite of novel pharmacodynamic assays performed on patient-derived peripheral blood cells and BM demonstrated a dose-dependent modulation of GSPT1, and showed that the preclinical mechanisms of ISR induction, NMD inhibition, and apoptosis can be confirmed in AML cells in patients. Deeper and more rapid GSPT1 degradation as well as delayed rebound were associated with more rapid, deeper, and more persistent blast reductions. Characterization of these pharmacodynamic responses in ongoing dose-schedule explorations will help identify the optimal scheme for the expansion phase and provide further insight into the mechanism of clinical response. Disclosures Fan: Celgene Corporation: Employment, Equity Ownership. Wang:Celgene Corporation: Employment. Couto:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties. Yao:Celgene Corporation: Employment. Uy:Astellas: Consultancy; Pfizer: Consultancy; Curis: Consultancy; GlycoMimetics: Consultancy. Zeidan:Pfizer: Consultancy, Honoraria, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Trovagene: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Research Funding; Jazz: Honoraria; Ariad: Honoraria; Agios: Honoraria; Novartis: Honoraria; Astellas: Honoraria; Daiichi Sankyo: Honoraria; Cardinal Health: Honoraria; Seattle Genetics: Honoraria; BeyondSpring: Honoraria; Otsuka: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Acceleron Pharma: Consultancy, Honoraria, Research Funding; Medimmune/AstraZeneca: Research Funding; Celgene Corporation: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding. Montesinos:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees. DeAngelo:Jazz Pharmaceuticals, Inc.: Consultancy; Takeda Pharmaceuticals: Consultancy; Shire: Consultancy; GlycoMimetics: Research Funding; Pfizer, Inc.: Consultancy; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; Incyte Corporation: Consultancy; Celgene Corporation: Consultancy; AbbVie, Inc.: Research Funding; Blue print Medicines: Consultancy, Research Funding; Amgen: Consultancy. Altman:Novartis: Consultancy; Cancer Expert Now: Consultancy; Biosight: Other: US Lead; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; France Foundation: Speakers Bureau; prIME Oncology: Speakers Bureau; PeerView: Speakers Bureau; Theradex: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Glycomimetics: Consultancy, Honoraria, Other: Data Safety and Monitoring Committee. Koprivnikar:Amgen: Speakers Bureau; Abbvie: Speakers Bureau; Pfizer: Honoraria; Novartis: Speakers Bureau. Vyas:Astellas: Speakers Bureau; Pfizer: Speakers Bureau; Abbvie: Speakers Bureau; Daiichi Sankyo: Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Forty Seven, Inc.: Research Funding. Fløisand:Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Honoraria; Novartis: Honoraria. Gjertsen:Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; EU Horizon 2020: Research Funding; KinN Therapeutics AS: Equity Ownership; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; BerGenBio: Consultancy, Membership on an entity's Board of Directors or advisory committees; ERA PerMed: Research Funding; The Norwegian Cancer Society: Research Funding; Helse Vest Health Trust: Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Research Council of Norway: Research Funding; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; ACTII AS: Equity Ownership. Buchholz:Celgene Corporation: Employment, Equity Ownership. Pourdehnad:Celgene Corporation: Employment, Equity Ownership. Pierce:Celgene Corporation: Employment, Equity Ownership.

Background: CC-90009 is a cereblon (CRBN) E3 ligase modulator (CELMoD) and a first-in-class small molecule that drives the binding of a novel target protein, G1 to S phase transition 1 (GSPT1), to CRBN, resulting in the proteasome-dependent degradation of GSPT1. GSPT1 plays a central role in mRNA translation, and loss of GSPT1 activates an integrated stress response that leads to AML cell death (Matyskiela ME, et al. Nature. 2016;535:252-7; Zhouravleva G, et al. EBMO J. 1995;14:4065-72). In preclinical testing, CC-90009 is active across a range of AML cell lines and primary AML patient (pt) samples in vitro and in vivo and exerts its GSPT1- and CRBN-dependent effects through rapid induction of apoptosis. Here we share the first clinical results in pts with R/R AML. Methods: Adult pts with R/R AML enrolled in the dose-finding phase of this first-in-human, multicenter, open-label phase 1 study to evaluate tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of CC-90009; and to establish the recommended phase 2 dose and schedule (RP2D) (CC-90009-AML-001; NCT02848001). Dose escalation proceeded via a modified 3 + 3 design. Treatment was by daily intravenous administration on either Days 1-5 (D1-5) or Days 1-3 and 8-10 (D1-3/8-10) of a 28-day cycle. Treatment response was assessed after Cycles 1, 2, and 4 by modified International Working Group 2003 criteria. Safety and preliminary response data are presented for all treated pts. PK and PD were analyzed for evaluable pts. Results: As of May 15, 2019, 45 pts with R/R AML had been treated, including 35 pts on the D1-5 and 10 pts on the D1-3/D8-10 schedule. Median age was 66 years (range 27-81); 73% were male. Most pts (n = 36; 80%) were refractory to their last therapy and 17 pts (38%) were refractory to all prior therapy; 14 pts (31%) had secondary AML. Pts were treated at dose levels from 0.3 to 3.6 mg. Dose-limiting toxicities (DLTs) reported (only in dose levels from 2.4 to 3.6 mg) included hypotension, systemic inflammatory response syndrome (SIRS), hyperbilirubinemia, pneumonitis, and pericarditis with tamponade. Exploration of the 3.6 mg dose level is ongoing; the RP2D has not yet been determined. CC-90009-related grade 3/4 treatment-emergent adverse events (TEAEs) occurred in 23 pts (51%); those occurring in >1 pt were hypocalcemia (22%); hypotension (13%); and hyperbilirubinemia, hyperglycemia, hypophosphatemia, pneumonitis, sepsis, thrombocytopenia, and tumor lysis syndrome (4%). Preclinically identified hypocalcemia was confirmed as a CC-90009 on-target toxicity in the clinic; it was reversible, manageable and did not lead to any treatment discontinuations. The majority of treated pts experienced ≥1 serious TEAE (80%); most were infections (47%). Two (4%) pts experienced TEAEs leading to permanent discontinuation of the study drug. Dose interruptions due to TEAEs occurred in 12 pts (27%) and dose reductions in 2 pts (4%). Of 40 pts who discontinued treatment, 24 (60%) discontinued due to progressive disease or lack of efficacy. Seven pts discontinued treatment due to death; 4 deaths were secondary to progression from AML, 2 due to sepsis and 1 due to hyperglycemic hyperosmolar nonketotic syndrome. Responses to single-agent treatment were observed in pts treated at 3.0 or 3.6 mg on the D1-5 schedule, with a best response of complete remission (CR; n = 1), morphologic CR with incomplete blood count recovery (CRi; n = 1) and morphologic leukemia-free state (MLFS; n = 1). A dose-dependent decrease in GSPT1 levels in peripheral blood blasts and T cells was observed, with a >90% decrease observed for higher dose levels. Evidence of antileukemic activity (decreases in bone marrow and/or peripheral blasts) was seen in pts treated with CC-90009 at 1.2 mg and above with a trend to more sustained reductions at the highest dose levels. Plasma PK analysis demonstrated dose-dependent exposure. Conclusions: In this phase 1 study of CC-90009, a first-in-class agent, evidence of deep GSPT1 degradation, on-target activity and promising antileukemic activity was observed. The observed TEAEs, in addition to those expected in this heavily pretreated R/R AML pt population, were generally well manageable. The study is ongoing with further optimization of dose, schedule and toxicity mitigation. Expansion cohorts in R/R AML and higher-risk myelodysplastic syndromes are planned. Disclosures Uy: GlycoMimetics: Consultancy; Curis: Consultancy; Astellas: Consultancy; Pfizer: Consultancy. Montesinos:Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. DeAngelo:Blue print Medicines: Consultancy, Research Funding; Celgene Corporation: Consultancy; Shire: Consultancy; Pfizer, Inc.: Consultancy; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; Incyte Corporation: Consultancy; Jazz Pharmaceuticals, Inc.: Consultancy; GlycoMimetics: Research Funding; AbbVie, Inc.: Research Funding; Takeda Pharmaceuticals: Consultancy; Amgen: Consultancy. Altman:Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Biosight: Other: US Lead; France Foundation: Speakers Bureau; PeerView: Speakers Bureau; Agios: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Glycomimetics: Consultancy, Honoraria, Other: Data Safety and Monitoring Committee; Cancer Expert Now: Consultancy; Theradex: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; prIME Oncology: Speakers Bureau; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Koprivnikar:Amgen: Speakers Bureau; Pfizer: Honoraria; Abbvie: Speakers Bureau; Novartis: Speakers Bureau. Vyas:Astellas: Speakers Bureau; Abbvie: Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Forty Seven, Inc.: Research Funding; Daiichi Sankyo: Speakers Bureau; Pfizer: Speakers Bureau; Novartis: Research Funding, Speakers Bureau. Fløisand:Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Honoraria; Novartis: Honoraria. Gjertsen:BerGenBio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees; EU Horizon 2020: Research Funding; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; The Norwegian Cancer Society: Research Funding; KinN Therapeutics AS: Equity Ownership; ACTII AS: Equity Ownership; ERA PerMed: Research Funding; Helse Vest Health Trust: Research Funding; Research Council of Norway: Research Funding. Esteve:Astellas: Consultancy, Speakers Bureau; Amgen: Consultancy; Novartis: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Daiichi Sankyo: Consultancy; Jazz Pharmaceuticals: Consultancy; Roche: Consultancy; Pfizer: Consultancy. Buchholz:Celgene Corporation: Employment, Equity Ownership. Couto:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties. Fan:Celgene Corporation: Employment, Equity Ownership. Hanna:Celgene Corporation: Employment, Equity Ownership. Li:Celgene Corporation: Employment, Equity Ownership. Pierce:Celgene Corporation: Employment, Equity Ownership. Hege:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties; Mersana Therapuetics: Membership on an entity's Board of Directors or advisory committees; Society for Immunotherapy of Cancer: Membership on an entity's Board of Directors or advisory committees; Arcus Biosciences: Membership on an entity's Board of Directors or advisory committees. Pourdehnad:Celgene Corporation: Employment, Equity Ownership. Zeidan:Pfizer: Consultancy, Honoraria, Research Funding; Medimmune/AstraZeneca: Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Trovagene: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Research Funding; Jazz: Honoraria; Ariad: Honoraria; Agios: Honoraria; Seattle Genetics: Honoraria; BeyondSpring: Honoraria; Cardinal Health: Honoraria; Daiichi Sankyo: Honoraria; Novartis: Honoraria; Otsuka: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Acceleron Pharma: Consultancy, Honoraria, Research Funding; Celgene Corporation: Consultancy, Honoraria, Research Funding; Astellas: Honoraria.

BACKGROUND AND OBJECTIVES: Chemosensitization using plerixafor combined with FLAG-IDA (PLERIFLAG regimen) showed promising results (48% CR/CRi) in a phase 2 trial for primary refractory and early relapsed (duration of first CR Patients: Of the 540 patients in the data base we analysed 300 patients relapsed or resistant to induction therapy, which had all data available. 241 patients were treated with FLAG-IDA, 41 with FLAGO-Ida, and 42 with PLERIFLAG. Differences between treatment cohorts were tested using Fisher exact test. Treatment cohorts (PLERIFLAG vs FLAG-IDA vs FLAGO-IDA) were similar in Age (p=0.5), Sex (p=0.5), FLT3-ITD mutated (p=0.5), EPI/HOVON cytogenetics score (p=0.5) and previous myelodisplasia (p=0.2). The three cohorts differed in time to relapse (p=0.001), previous stem cell transplantation (0.001), HOVON score (p=0.03) and SALFLAGE score (0.001). RESULTS There were no differences in terms of CR+CRi between the three types of treatment adjusted by Hovon risk score (Pleriflag: 48%, FLAG-IDA: 50% or FLAGO-IDA: 58%; Chrochan Maentel-Haenszel test, p=0.466) or SALFLAGE score (Chrochan-Maentel-Haenszel test, p=0.23). More patients were allografted in the PLERIFLAG (61%) group even not achieving CR/Cri, as compared to FLAG-IDA (38%) or FLAGO-Ida (61% vs 38% vs. 18%, p=0.0001). To compare PLERIFLAG against the other two types of salvage treatment we performed a Propensity Score in a proportion 1:3. We adjust variables like age, previous allogeneic transplant, time to relapse (refractory, 12 months), karyotype using MRC, and FLT3-ITD status. Karyotype risk was considered by HOVON criteria (inv16, t(8;21) vs others), and SALFLAGE (inv 16, intermediate risk, and unfavourable risk by MRC risk plus t(8;21)). The propensity score analyses showed that Compared to FLAG-IDA, PLERIFLAG was associated to increased survival (median OS 10.56 months vs. 5.6, p=0.03), but not improved EFS (2.83 months vs 1.41 months, p=0.8). The benefit in OS but not in EFS could be explained in part by frequent use of Allo SCT in patients who had not achieve CR/CRi in the PLERIFLAG cohort. In conclusion, our historical control study show that PLERIFLAG regimen is an acceptable therapeutic option for first relapsed/refractory adult AML patients. Disclosures Esteve: Jazz Pharmaceuticals: Consultancy; Amgen: Consultancy; Pfizer: Consultancy; Novartis: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Daiichi Sankyo: Consultancy; Roche: Consultancy; Astellas: Consultancy, Speakers Bureau. Salamero:Novartis: Honoraria; Pfizer: Honoraria; Celgene: Honoraria; Daichii Sankyo: Honoraria. Perez Encinas:CELGENE: Consultancy; JANSSEN: Consultancy; GILEAD SCIENCES: Research Funding. Montesinos:Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research support, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: Research support; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Other: Research support, Research Funding, Speakers Bureau.

Introduction. Nucleophosmin gene mutation (NPM1mut) occurs in around 30% of acute myeloid leukemia (AML) patients, frequently linked with favourable prognosis in the absence of FLT3-ITDmut, which occurs in around 40% of NPM1mutAML. Therefore, more expeditious diagnostic approaches may contribute to early diagnosis and prognostic stratification of these patients. Herein, we investigated the association of immunophenotypic features of leukemic and monocytic cells with the presence of NPM1mut in AML. Methods. A total of 404 bone marrow (BM) samples from newly-diagnosed AML patients according to WHO 2017 classification were retrospectively studied by 8-color flow cytometry, including 225 AML with NPM1mut and 179 cases wild type gene (NPM1wt). Information on FLT3-ITD could be obtained from 397/404 cases. Thus, FLT3-ITDmut was present in 85/397 (21%), being concomitant with NPM1mutin 62/85 AML cases (73%). Logistic regression analysis was used to identify predictive phenotypes for the presence of NPM1mut. Results. Overall, blast cell with immunophenotypic features of monocytic differentiation (corresponding to FAB M4 and M5 AML subtypes) were observed among 135/225 (60%) and 69/179 (38.5%) AML patients with NPM1mutand NPM1wt, respectively (p Among AML with monocytic blast cell differentiation, altered monocytic phenotypes were more frequent among NPM1mut vs. NPM1wtcases (98% vs. 36%) (p Noteworthy, in AML cases without blast cell monocytic differentiation, remaining monocytic cells showed similar asynchronous phenotypic patterns, which were also more frequent among NPM1mut cases (78% vs. 23% of NPM1wtcases, respectively; p In addition, aberrant CD9 blast cell expression was found in a significant proportion of all AML cases studied (124/222, 56%). However, altered CD9 was more frequent on (either monocytic or immature/myeloid) blast cells from AML cases with NPM1mut (76% vs. 46% NPM1wtcases; p0.05). In turn, aberrant CD25 expression on blast cells was otherwise linked to FLT3-ITDmut (61% vs. 20% of FLT3-ITDwtcases; p In multivariate analysis, baseline detection of monocytic-lineage blast cells with asynchronous expression of CD300 prior CD14 -C-index= 0.954, odds ratio (OR), 78.8; 95% confidence interval (CI), 13.1-471; p Conclusions. Detection of specific aberrant immunophenotypic patterns among blast cells and/or remaining monocytic cells from AML patients is highly predictive for NPM1mut, which may contribute to early diagnosis and follow-up of these patients. Disclosures Díez-Campelo: Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Circulating myeloma tumor cells (CTCs) as defined by the presence of peripheral blood (PB) clonal plasma cells (PCs) are a powerful prognostic marker in multiple myeloma (MM). However, the biological features of CTCs and their pathophysiological role in MM remains unexplored. Here, we investigate the phenotypic, cytogenetic, and functional characteristics as well as the circadian distribution of CTCs vs paired bone marrow (BM) clonal PCs from MM patients. Our results show that CTCs typically represent a unique subpopulation of all BM clonal PCs, characterized by downregulation (P < .05) of integrins (CD11a/CD11c/CD29/CD49d/CD49e), adhesion (CD33/CD56/CD117/CD138), and activation molecules (CD28/CD38/CD81). Fluorescence in situ hybridization analysis of fluorescence-activated cell sorter-sorted CTCs also unraveled different cytogenetic profiles vs paired BM clonal PCs. Moreover, CTCs were mostly quiescent and associated with higher clonogenic potential when cocultured with BM stromal cells. Most interestingly, CTCs showed a circadian distribution which fluctuates in a similar pattern to that of CD34(+) cells, and opposite to stromal cell-derived factor 1 plasma levels and corresponding surface expression of CXC chemokine receptor 4 on clonal PCs, suggesting that in MM, CTCs may egress to PB to colonize/metastasize other sites in the BM during the patients' resting period.

Previous studies have shown that clofarabine plus low-dose cytarabine (LDAC) could induce roughly 60 % of complete remissions (CR) with acceptable toxicity and induction mortality in elderly acute myeloid leukemia (AML) patients not suitable for intensive chemotherapy. The Programa Espanol de Tratamientos en Hematologia group conducted a trial for patients diagnosed with untreated AML aged 60 years and older, using the combination of clofarabine (20 mg/m2 × 5 days) plus low-dose cytarabine (20 mg/m2 × 14 days). The protocol was flexible regarding the use of antifungal and antibacterial prophylaxis, and outpatient induction therapy was allowed. Although the planned recruitment goal was 75 patients, only 11 patients were enrolled (median age, 74 years) after observing high toxicity and unacceptable mortality (46 and 73 % at 4 and 8 weeks, respectively). The response assessment showed three CR (27 %), three resistant diseases (27 %), and five induction deaths (46 %). Induction was administered in an outpatient modality in five patients, while antifungal and antibacterial prophylaxis was not given in seven and five patients, respectively. In our context, induction therapy with the combination of clofarabine (20 mg/m2) plus LDAC was associated with high toxicity and unacceptable mortality in elderly AML patients, leading to the early interruption of the trial. Tight patients’ clinical monitoring, follow-up, and intensive supportive care seem crucial to achieve at least acceptable clinical outcomes in elderly AML patients receiving clofarabine plus LDAC. This trial is registered at www.clinicaltrials.gov as no. NCT01193400.

Purpose Bortezomib-thalidomide-dexamethasone (VTD) is an effective induction therapy in multiple myeloma (MM). This phase II, noncomparative study sought to determine whether addition of cyclophosphamide to this regimen (VTDC) could further increase efficacy without compromising safety. Patients and Methods Patients age 18 to 70 years with previously untreated, measurable MM, who were eligible for high-dose chemotherapy–autologous stem-cell transplantation (HDCT-ASCT), were randomly assigned to bortezomib 1.3 mg/m2, thalidomide 100 mg, and dexamethasone 40 mg, with (n = 49) or without (n = 49) cyclophosphamide 400 mg/m2 for four 21-day cycles, followed by HDCT-ASCT. The primary end point was postinduction combined rate of near-complete response (nCR) or better (including complete response [CR] with normalized serum κ:λ free light chain ratio, CR, and nCR). Results Postinduction, 51% (VTD) and 44% (VTDC) of patients achieved combined CR/nCR, with bone marrow–confirmed CR in 29% and 31%, overall response rates of 100% and 96%, respectively, and very good partial response or better rates of 69% per arm. Post–HDCT-ASCT, combined CR/nCR rates were 85% (VTD) and 77% (VTDC). In all, 35% (VTD) and 27% (VTDC) of patients were negative for minimal residual disease (MRD) during induction and postinduction. Three-year overall survival was 80% (both arms). Grade 3 to 4 adverse events (AEs) and serious AEs were observed in 47% and 22% (VTD) and 57% and 41% (VTDC) of patients, respectively. The primary health-related quality of life end point (European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 [EORTC QLQ-C30] Global Health score) steadily increased with VTD during induction and reached a clinically relevant difference post-transplantation versus baseline. Conclusion Both VTD and VTDC are highly active induction regimens producing high combined CR/nCR and MRD-negative rates; however, VTDC was associated with increased toxicity and suggestion of transient decreases in Global Health score, without an increase in activity.

Prognostic factors in Hodgkin lymphoma (HL) still fail to accurately identify high-risk patients. Tumor microenvironment in HL is a current focus of research for risk definition but few studies have focused on infiltrating lymphocytes. Here, we analyzed the number of tumor infiltrating lymphocytes by flow cytometry in diagnostic biopsies from 96 HL homogeneously treated patients with ABVD with or without radiotherapy. Most lymph node cells were lymphocytes (90 ± 17), with a median T/B/NK distribution of 74%/26%/0.7%, and CD4 T-cell predominance. The amount of CD19 B cells, and NK cells did not show association with disease features. However, high numbers of CD8 and CD4 cells were associated with better and poorer outcomes, respectively. Patients with ≥15% cytotoxic CD8 cells among the total cell population had a longer 10-year freedom from treatment failure (FFTF) (93% vs. 73%, p=.04). In turn, cases with ≥75% of CD4 infiltrating cells showed a significantly decreased FFTF (73% vs. 96%, p=.021). Consequently, CD4/CD8 ratio ≥5 associated with a poorer 10-year FFTF (69.5% vs. 94%, p=.02). This deleterious effect was particularly prominent in advanced disease (n = 58, p=.01). In multivariate analysis, a CD4/CD8 ratio ≥5 was the only independent variable to predict for treatment failure (HR = 4.5, 95% confidence interval, 1.2–16.8). In conclusion, our study shows that high CD4 and low CD8 T-cells infiltrates of tumor specimens associate with poor prognosis in HL patients, and CD4/CD8 ratio might be potentially useful for tailoring therapy.

Immunoparesis or suppression of polyclonal immunoglobulins is a very common condition in newly diagnosed myeloma patients. However, the recovery of polyclonal immunoglobulins in the setting of immune reconstitution after autologous stem cell transplantation and its effect on outcome has not yet been explored. We conducted this study in a cohort of 295 patients who had undergone autologous transplantation. In order to explore the potential role of immunoglubulin recovery as a dynamic predictor of progression or survival after transplantation, conditional probabilities of progression-free survival and overall survival were estimated according to immunoglobulin recovery at different time points using a landmark approach. One year after transplant, when B-cell reconstitution is expected to be completed, among 169 patients alive and progression free, 88 patients (52%) showed immunoglobulin recovery and 81 (48%) did not. Interestingly, the group with immunoglobulin recovery had a significantly longer median progression-free survival than the group with persistent immunoparesis (median 60.4 vs. 27.9 months, respectively; Hazard Ratio: 0.45, 95%Confidence Interval: 0.31-0.66; P

BackgroundAlthough consensus guidelines have been proposed in 2010 for the diagnostic screening of paroxysmal nocturnal hemoglobinuria (PNH) by flow cytometry (FCM), so far no study has investigated the efficiency of such medical indications in multicentric vs. reference laboratory settings. MethodsHere we evaluate the efficiency of consensus medical indications for PNH testing in 3,938 peripheral blood samples submitted to FCM testing in 24 laboratories in Spain and one reference center in Brazil. ResultsOverall, diagnostic screening based on consensus medical indications was highly efficient (14% of PNH+ samples) both in the multicenter setting in Spain (10%) and the reference laboratory in Brazil (16%). The highest frequency of PNH+ cases was observed among patients screened because of bone marrow (BM) failure syndrome (33%), particularly among those with aplastic anemia (AA; 45%) and to a less extent also a myelodysplastic syndrome (MDS; 10%). Among the other individuals studied, the most efficient medical indications for PNH screening included: hemolytic anemia (19%), hemoglobinuria (48%) and unexplained cytopenias (9%). In contrast, only a minor fraction of the patients who had been submitted for PNH testing because of unexplained thrombosis in the absence of cytopenia, were positive (0.4%). ConclusionsIn summary, our results demonstrate that the current medical indications for PNH screening by FCM are highly efficient, although improved screening algorithms are needed for patients presenting with thrombosis and normal blood cell counts. (c) 2016 International Clinical Cytometry Society

Clonal plasma cell disorders (PCDs) encompass a heterogeneous group of distinct entities characterized in common by a clonal expansion and accumulation of plasma cells (PCs) in the bone marrow (BM) and/or other tissues, which is associated in the vast majority of cases with the presence of their product(s) (monoclonal immunoglobulin [Ig], M component) at detectable amounts in serum or urine (1). Although the so-called diseases of immunoglobulin deposits (e.g., primary light chain [AL] amyloidosis) and lymphoplasmacytic lymphoma (e.g., Waldenstrom macroglobulinemia) also belong to this heterogeneous group of disorders, its most representative diagnostic subtypes include monoclonal gammopathy of undetermined significance (MGUS), solitary plasmacytoma, multiple myeloma (MM), plasma cell leukemia (PCL), and several subvariants of these entities (1, 2) (Table 1). The last four diagnostic categories of PCD are the main focus of this chapter.

For PETHEMA Programa para el Estudio de la Terapéutica en Hemopatías Malignas Cooperative Study Group., The clinical utility of minimal residual disease (MRD) analysis in acute myeloid leukaemia (AML) is not yet defined. We analysed the prognostic impact of MRD level at complete remision after induction therapy using multiparameter flow cytometry in 306 non-APL AML patients. First, we validated the prognostic value of MRD-thresholds we have previously proposed (≥0.1%; ≥0.01-0.1%; and, This work was supported in part by Spanish grants from Fondo de Investigación Sanitaria-ISCIII (FIS 00/0023-03, PI12/02321), DGCYT (SAF 94- 0308, SAF2001-1687), Conserjería de Educación de Castilla y León (HUS416A12), and Red Temática de Investigación Cooperativa en Cáncer (RTICC-ISCIII) (RD12/0036/0069).

The incorporation of high-dose therapy/autologous stem cell transplantation (HDT/ASCT) and novel agents has significantly improved survival in patients with multiple myeloma (MM), but whether this improvement also benefits patients harboring poor prognostic features, such as nonhyperdiploid MM (NH-MM) and a high proliferation index, remains largely unknown. We analyzed the DNA content and proliferation index of bone marrow plasma cells (PCs) by multiparameter flow cytometry in 595 newly diagnosed transplant-eligible patients with MM included in two consecutive PETHEMA/GEM trials: GEM2000 [VBMCP/VBAD (vincristine, carmustine, melphalan, cyclophosphamide, prednisone/vincristine, bischloroethylnitrosourea, adriamycin, and dexamethasone) followed by HDT/ASCT; n = 319] and GEM2005

The clinical value of multiparameter flow cytometry (MFC) immunophenotyping in primary or light chain amyloidosis (AL) remains unknown. We studied 44 consecutive bone marrow samples from newly diagnosed patients with amyloidosis; 35 patients with AL and 9 with other forms of amyloidosis. Monoclonal plasma cells (PCs) were identifiable by MFC immunophenotyping in 34 of 35 (97%) patients with AL, whereas it was absent from all but 1 of the 9 (11%) patients with other forms of amyloidosis. Quantification of bone marrow plasma cells (BMPCs) by MFC immunophenotyping was a significant prognostic factor for overall survival (OS) (≤ 1% vs > 1% BMPC cutoff; 2-year OS rates of 90% vs 44%, P = .02). Moreover, detecting persistent normal PCs at diagnosis identifies a subgroup of patients withAL with prolonged OS (> 5% vs ≤ 5% normal PC within all BMPC cutoff, 2-year rates of 88% vs 37%, P = .01). MFC immunophenotyping could be clinically useful for the demonstration of PC clonality in AL and for the prognostication of patients with AL. © 2011 by The American Society of Hematology., This work was supported by the Cooperative Research Thematic Cancer Network (RTIC) grants RD06/0020/0006 and G03/136, MM Jevitt, SL firm, Instituto de Salud Carlos III/Subdirección General de Investigación Sanitaria (FIS) grants PI060339, 02/0905, 01/0089/01-02, PS09/01897, and Consejería de Sanidad, Junta de Castilla y León, Valladolid, Spain grant 557/A/10.

Letter to the editor.-- et al., This study was supported by the Cooperative Research Thematic Network grants RD12/0036/0058 of the Red de Cancer (Cancer Network of Excellence); Instituto de Salud Carlos III, Spain, Instituto de Salud Carlos III/Subdirección General de Investigación Sanitaria (FIS: PI060339; 06/1354; 02/0905; 01/0089/01-02; PS09/01897/01370; G03/136; Sara Borrell: CD13/00340); and Asociación Española Contra el Cáncer (GCB120981SAN), Spain. The study was also supported internationally by the International Myeloma Foundation Junior Grant Proposal and the Multiple Myeloma Research Foundation research fellow award.

Background: Despite significant improvements in the treatment of MM, the outcome of patients with HR cytogenetics remains poor despite similar complete remission (CR) rates as compared to SR cases. Relapses among patients in CR are attributed to the persistence of MRD, but knowledge about the impact of MRD in patients with SR and HR cytogenetics, treated with modern therapies and monitored with next-generation techniques, is limited. Similarly, there is virtually no data about in vivo mechanisms of resistance in SR and HR MM; however, since MRD represents those very few cells that are resistant to treatment, it could be hypothesized that profiling MRD cells may shed light into the mechanisms of resistance in both SR and HR patients. Aim: To determine the clinical impact of MRD in MM patients with SR vs HR cytogenetics, and to identify transcriptional mechanisms determining MRD resistance by investigating the transcriptome of MRD cells in both patient subgroups. Methods: This study was conducted in a series of 390 patients enrolled in the PETHEMA/GEM2012 trial (6 induction cycles with VRD followed by ASCT and 2 courses of consolidation with VRD). FISH was analyzed on CD138 purified PCs at diagnosis. MRD was predefined to be prospectively assessed following induction, transplant and consolidation, using next-generation flow (NGF) according to EuroFlow. In 40 patients [28 with SR and 12 with HR cytogenetics: i.e., t(4;14), t(14;16) and/or del(17p)], diagnostic and MRD tumor cells persisting after VRD-induction were isolated by FACS according to patient-specific aberrant phenotypes. Due to the small number of sorted MRD cells (median of 25,600) we used a 3' end RNAseq method optimized for generating libraries from low-input starting material (MARSeq). Differential expression analyses were performed with DESeq2 R package. Results: At the latest time-point in which MRD was assessed, MRD-positive rates progressively increased (p =.006) from SR patients (148/300, 49%) to cases with t(4;14) (24/42, 57%) and del(17p) (29/38, 76%). Furthermore, MRD levels were significantly superior in patients with del(17p) compared to SR FISH (0.02% vs 0.006%, p =.009), while MRD levels in patients with t(4;14) (0.004%) were similar to those in SR MM. Only 10 patients had a t(14;16) and 4 were MRD-positive. Among patients achieving MRD-negativity (.05). Conversely, 3-year PFS rates for MRD-positive patients decreased from those having SR FISH to those with t(4;14) and del(17p) (59%, 46% and 24%, respectively), with statistically significant differences between the first and the latest subgroups (p Since clearance of MRD notably lowered the risk of relapse and persistence of MRD significantly shortened the PFS in each cytogenetic group (p ≤.001), we investigated the unique features of MRD cells persisting after VRD-induction by comparing their transcriptome to that of patient-matched tumor cells at diagnosis (n=40). Accordingly, MRD cells showed 763 genes significantly deregulated (Padj Conclusions: This is one of the largest studies integrating patients' cytogenetics and MRD status. Our results, based on intensive treatment and MRD monitoring using NGF, unveil that achieving MRD-negativity may overcome the poor prognosis of HR cytogenetics. By contrast, persistent MRD significantly reduces PFS rates, particularly in patients with del(17p). Interestingly, MRD cells from SR and HR patients may have different transcriptional mechanisms leading to VRD resistance, and further understanding of these could provide knowledge on how to eradicate MRD in both patient subgroups. Disclosures Puig: Takeda: Consultancy, Honoraria; Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Garcia-Sanz:Affimed: Research Funding. Martinez-Lopez:BMS: Research Funding; Pfizer: Research Funding; Vivia: Honoraria; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Research Funding. Oriol:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rios:Amgen, Celgene, Janssen, and Takeda: Consultancy. De La Rubia:Ablynx: Consultancy, Other: Member of Advisory Board. Mateos:GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: 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; Janssen: 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. Lahuerta:Janssen: 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; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bladé:Janssen: Honoraria. San-Miguel:Amgen: Honoraria; BMS: Honoraria; Novartis: Honoraria; Sanofi: Honoraria; Celgene: Honoraria; Roche: Honoraria; Janssen: Honoraria.

Background: Since survival in AL mainly depends on the extent of organ involvement of patients at presentation, early diagnosis and risk stratification are key to improve patients' outcome. Therefore, together with surrogates of organ involvement, biomarkers identifying patients with MGUS or MM at greater risk of developing AL would be highly valuable to prevent organ damage, to maximize therapeutic efficacy and to improve outcomes in AL. Aim: To investigate the value of multidimensional flow cytometry (MFC) for simultaneous fast diagnostic screening of plasma cell (PC) clonality and risk stratification, as well as to identify immunophenotypic markers useful for the selection of patients with monoclonal gammopathies candidates for monitoring of pre-symptomatic organ damage related to AL. Methods: We used MFC to characterize a large series of patients with newly-diagnosed (ND) AL (N=94) vs MGUS (N=20) and NDMM (N=52), as well as age-matched healthy adults (HA, N=30). For each patient with AL, automated risk stratification was performed using principal component analysis (PCA) based on the relative frequency of bone marrow (BM) PCs, plus the percentage of clonal and normal PCs within the whole BM PC compartment, vs a database containing information on the same three parameters from a total of 1,774 patients, including 497 MGUS and 1,227 NDMM. In parallel, immunophenotypic protein expression profiles (iPEP) of AL patients were clustered using t-SNE, and the comparison between the iPEP of clonal PCs from patients with AL vs MGUS and MM cases was performed using canonical-correlation analysis (CCA). To identify additional immunophenotypic hallmarks of AL, the BM cellular composition in HA, MGUS, AL and MM patients was compared using 2-dimensional minimum spanning tree (MST) force-directed classification to determine the distance among individual cases. Results: PC clonality was detected by MFC in 93/94 (99%) AL patients, whereas an M-component was detectable in 96% of cases by electrophoresis, immunofixation and sFLC. PCA as defined above, identified AL patients displaying an MM-like (n=6) and an MGUS-like (n=38) signature, as well as 49 cases with an intermediate signature between the MGUS and MM reference datasets. Multivariate analysis of baseline prognostic factors for survival, including patients' age, number of organs involved, Mayo staging, the percentage of BM PCs based on cytomorphology and eligibility for ASCT, showed that having an intermediate- or an MM-like profile had an independent adverse effect on patients' progression-free (PFS) and overall survival (OS) (HR:3.4; P≤.02). t-SNE based on the iPEP of clonal PCs revealed two major clusters of AL patients with significantly different PFS, defined by opposite patterns of expression for CD45, CD56 and CD138 (P≤.02). CCA of tumor iPEP showed partial overlap between AL vs MGUS and MM, with progressively higher percentages of cases with a CD38lo, CD45-ve, CD81-ve and CD138lo iPEP being observed from MGUS to AL and MM. In contrast, AL patients displayed significantly lower reactivity for CD56 (P≤ .03). Further characterization of the BM cellular composition allowed the systematic assessment of 16 cell populations and 18 phenotypic parameters that, by MST, mapped AL in between MGUS and MM. Of note, while AL patients displayed a predominantly-clonal PC compartment in the absence of an MM-like tumor PC expansion, the percentage of B-cell precursors was consistently lower in AL patients than in HA, MGUS and MM (P=.004). Thus, using optimal cut-off values to discriminate between AL vs MGUS and MM, we built a scoring model based on the presence of 80% clonal PCs within total BM PCs and Conclusions: We demonstrate the value of MFC for fast diagnostic screening of PC clonality in AL and simultaneous automated patient risk-stratification, based on the BM tumor burden and PC phenotype. In addition, our results also provide new immunophenotypic markers for the identification of patients with monoclonal gammopathies that are candidates for monitoring of pre-symptomatic organ damage related to AL. Disclosures Puig: Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Celgene: Honoraria, Research Funding. Ocio:Array Pharmaceuticals: Research Funding; Sanofi: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Pharmamar: Consultancy; BMS: Consultancy; AbbVie: Consultancy; Janssen: Consultancy, Honoraria; Seattle Genetics: Consultancy; Mundipharma: Research Funding; Takeda: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Oriol:Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. De La Rubia:Ablynx: Consultancy, Other: Member of Advisory Board. Martinez Lopez:Janssen: Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Bristol Myers Squibb: Research Funding, Speakers Bureau. Mateos:Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, 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; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Lahuerta:Janssen: Honoraria; Celgene: Honoraria; Amgen: Honoraria.

Cytogenetic analysis is still an important and mandatory component of Acute Myeloid Leukemia (AML) diagnosis and prognosis. Pretreatment cytogenetic and molecular genetic findings are one of the major independent prognostic markers in AML, and they determine chemotherapy response and outcome. However, cytogenetic does not provide alternative treatments when a patient have a high cytogenetic risk, and requires relatively long time until obtaining the results despite the treatment of these patients should begin as soon as possible. The aim of this study is providing data about the utility of a new AML Precision Medicine (PM) Test as a complementary tool to conventional cytogenetic to overcome the main obstacles this later has. For this purpose, AML bone marrow from 111 patients were received at the laboratory 24h from extraction and incubated for 48h in 96-well plates containing single drugs or combinations, representing up to 31 different treatments that are currently given in the clinical practice. The analyses were performed in the automated flow cytometry PharmaFlow platform and the test results can be sent to the hematologists 72h after the extraction of the sample. Pharmacological responses were calculated using pharmacokinetic population models. Induction response was assessed according to the Cheson criteria (2003). Patients attaining a complete remission (CR) or CR with incomplete blood count recovery (CRi) were classified as responders and the remaining as resistant, excluding early deaths. The probability of being resistant or non-responder was modeled using binary logistic generalized additive models (GAM) with Cytarabine (CYT) and Idarubicin (IDA) area under the curve (AUC) data and over the cytogenetic risk (favorable/intermediate/adverse). The empirical ROC curves were calculated for the probabilities of being non-responder from each GAM. Final scores and treatments ranking are based on a therapeutic algorithm that integrates ex vivo activity of single drugs, quantified by the AUC and synergism, referred as α parameter, using a surface interaction model. Clinical and cytogenetic risk data of the patients were monitored and collected. A simple logistic model of the probability of being non-responder over the cytogenetic risk (favorable/intermediate/adverse) explained less variability (29.4%) than the GAM over the AUC values (40.8%) in the subset of 111 patients in whom the cytogenetic risk was informed. Figure 1 shows the results of the clinical correlation of cytogenetics vs PM Test in the cohort of 111 patients analyzed. In both approaches prediction of sensitive patients (Negative Prediction Value, NPV) is better than resistant patients (Positive Predictive Value, PPV), being the PM Test slightly better in predicting the sensitive patients (NPV=93% vs 88%), while the cytogenetics shows a 20% improvement in the prediction of resistant patients (PPV= 76% vs 56% with PM Test). The correlation achieved by the PharmaFlow PM test was 80% that is almost similar than the correlation obtained with the cytogenetic data using the same cut off point (86%). Figure 1 (right) also shows an example of the classification of AML treatments with the PharmaFlow PM Test in a patient sample according to a color scale from higher (green) to lower (red) ex vivo activity. In summary, despite the PharmaFlow PM Test and cytogenetics provide similar information, results from cytogenetic risk are available typically in 10-14 days, and thus after patient treatment, while results from this novel PM Test are available in 48-72h, prior to treatment. Hence, this novel approach provides information to hematologist with higher predictive value than risk factor (deviance explained 40.8% vs 29.4%) and ahead of treatment, and thus represent a valuable in-time prior to treatment decision making. In addition, the PM Test can provide alternative treatments to AML patient in a basis of their ex vivo activity. Disclosures Ballesteros: Vivia Biotech: Employment. Martinez Lopez:Novartis: Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Bristol Myers Squibb: Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau. Hernandez:Vivia Biotech: Employment. Primo:Vivia Biotech: Employment. Gorrochategui:Vivia Biotech: Employment. Rojas:Vivia Biotech: Employment. Montesinos:Novartis: Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Speakers Bureau.

Aberrant CD117 expression is associated with a favorable outcome in multiple myeloma. We analyzed 106 patients with symptomatic multiple myeloma (n=50), smoldering multiple myeloma (n=38) and monoclonal gammopathy of undetermined significance (n=18) to elucidate biological features of CD117(+) versus CD117(-) monoclonal gammopathies. CD117(+) (mono)clonal plasma cells were detected in 30% symptomatic multiple myeloma, 45% smoldering multiple myeloma and 72% monoclonal gammopathy of undetermined significance patients. CD117 expression was associated with higher percentages of normal bone marrow plasma cells, CD117(+) myeloid precursors and CD38(+) B lymphocytes in all monoclonal gammopathies. Conversely, the number of bone marrow CD34(+) myeloid cells and peripheral blood neutrophils was reduced among CD117(+) multiple myeloma but not monoclonal gammopathy of undetermined significance patients. CD117 expression by (mono)clonal plasma cells is associated with uniquely altered patterns of production of hematopoietic bone marrow cells with decreased peripheral blood neutrophil counts and persistence of normal residual bone marrow plasma cells.

The PI3/AKT pathway is up-regulated in acute myeloid leukemia (AML), but its prognostic relevance in cytogenetically normal AML (CN-AML) is unclear. We evaluated RNA levels of AKT and two downstream substrates (FOXO3a-p27) in 110 de novo CN-AML, included in the Spanish PETHEMA therapeutic protocols. Patients with high FOXO3a gene expression displayed shorter OS (p = 0.015) and RFS (p = 0.048) than low FOXO3a expressers. Features selected in the multivariate analysis as having an independent prognostic value for a shorter survival were WBC > 50 × 109/L, age >65 years and high FOXO3a expression. We concluded that FOXO3a assessment could contribute to improve the molecular-based risk stratification in CN-AML. © 2009 Elsevier Ltd. All rights reserved., This work has been partially supported with the grants PI061351 and 00/0023-00 from the Spanish “Fondo de Investigaciones Sanitarias de la Seguridad Social”, 89/A/06 from “Gerencia Regional de Salud, Junta Castilla y León”, CR-USA Foundation-Spanish National Research Council (CSIC) Cooperative Agreement and CIC, IBMCC (USAL-CSIC), Spain.

Multiparameter flow cytometry immunophenotyping allows discrimination between normal (N-) and myelomatous (MM-) plasma cells (PCs) within the bone marrow plasma cell compartment (BMPCs). Here we report on the prognostic relevance of detecting more than 5% residual normal plasma cells from all bone marrow plasma cells (N-PCs/BMPCs) by multiparameter flow cytometry in a series of 594 newly diagnosed symptomatic MM patients, uniformly treated according to the Grupo Español de MM 2000 (GEM2000) protocol. Our results show that symptomatic MM patients with more than 5% N-PCs/BMPCs (n = 80 of 594; 14%) have a favorable baseline clinical prospect, together with a significantly lower frequency of high-risk cytogenetic abnormalities and higher response rates. Moreover, this group of patients had a significantly longer progression-free survival (median, 54 vs 42 months, P = .001) and overall survival (median, not reached vs 89 months, P = .04) than patients with less than or equal to 5% N-PCs/BMPCs. Our findings support the clinical value of detecting residual normal PCs in MM patients at diagnosis because this reveals a good prognostic category that could benefit from specific therapeutic approaches. This trial was registered at www.clinicaltrials.gov as NCT00560053.

Quantification of bone marrow plasma cells in multiple myeloma patients using conventional morphology is of limited prognostic value, while the merit of multiparameter flow cytometry immunophenotyping is still considered unproven. Here we compare the bone marrow plasma cell counts obtained by morphology and multiparameter flow cytometry and explore the potential prognostic impact of both techniques in 765 newly diagnosed, uniformly treated multiple myeloma patients. Although multiparameter flow cytometry generally yields lower plasma cell counts (median percentage of 11% vs. 40%, respectively; p

BACKGROUND: Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by a deficient expression of glycosylphosphatidylinositol-anchored proteins (GPI-APs), due to somatic mutations of the phosphatidylinositolglycan complementation Class A (PIG-A) gene. STUDY DESIGN AND METHODS: In this study, the expression of a high number of GPI-APs on different subsets of peripheral blood (PB) cells from 14 PNH patients and their potential association with underlying genetic abnormalities has been analyzed. RESULTS: This study confirms the existence of variable patterns of expression of different GPI-APs on both major and minor PB-cell subsets from PNH patients. The size of the PNH clone within PB neutrophils and monocytes was systematically higher than that of other cell populations. Genetic changes were detected in the PIG-A gene in 5 of 13 cases analyzed. Interestingly, the reactivity for many GPI-APs was significantly higher on different subsets of normal PB cells from PNH patients than those observed on healthy volunteers. CONCLUSION: The best combination of markers for the diagnostic screening of PNH would include evaluation of CD14 on monocytes and of CD16 on neutrophils, although further analysis of CD55 and CD59 expression may contain additional clinically useful information. Clear association between the genetic changes detected in the PIG-A gene in 5 of 13 cases analyzed, and the phenotypic profile of PNH cells has not been found. Additionally, an abnormally higher expression of several GPI-APs among normal residual cells from PNH patients in comparison to healthy donors was observed, suggesting that factors other than the PIG-A mutation could determine the phenotypic profile of PB cells in PNH.

Purpose To analyze the prognostic impact of immunophenotyping in patients with multiple myeloma (MM). Patients and Methods We have prospectively analyzed the prognostic impact of antigenic markers, assessed by multiparametric flow cytometry, in a series of 685 newly diagnosed MM patients that were uniformly treated according to the GEM 2000 protocol. Results Our results show that expression of both CD19 and CD28 as well as the absence of CD117 were associated with a significantly shorter progression free-survival (PFS) and overall survival (OS). Interestingly, the CD28 expression correlated with t(14;16) and del(17p), while CD117-negative patients were associated with t(4;14) and del(13q). Simultaneous assessment of CD28 and CD117 antigens allowed stratification of patients with MM into three risk categories: poor risk (CD28 positive CD117 negative), intermediate (either both markers negative or both positive), and good risk (CD28 negative CD117 positive), with PFS rates of 30, 37, and 45 months, respectively (P = .01), and OS rates of 45, 68, and not reached, respectively (P = .0001). Conclusion To the best of our knowledge, this is the first prospective analysis in which the prognostic impact of a relatively high number of antigenic markers has been simultaneously analyzed in a large series of uniformly treated patients, showing that the expression of several antigens (particularly CD28 and CD117) on bone marrow plasma cells from patients with MM can help to identify patients at high risk of progression.

[Background]: Proteasome inhibition represents a promising novel anticancer therapy, and bortezomib is a highly selective reversible inhibitor of the proteasome complex. Acute myeloid leukemia (AML) is an immnunophenotypically heterogeneous group of diseases, with CD34+ cases being associated with drug resistance and poor outcome. We investigated the effects of bortezomib on the growth and survival of AML cells. [Design and Methods]: We studied the in vitro activity and mechanism of action of bortezomib on both cell lines and fresh cells from 28 AML patients including CD34+ and CD34- cases. [Results]: Bortezomib showed potent anti-AML activity (IC50 < 50 nM), which was greater than that of conventional agents (doxorubicin, cytarabine and fludarabine). Moreover, synergistic effects were observed when bortezomib was adminstered in combination with doxorubicin and cytarabine. Mechanistically, bortezomib induced accumulation of cells in the G2/M phase, with up-regulation of p27, together with cell death through an increase in the mitochondrial outer membrane permeability involving caspase-dependent and -independent pathways. The apoptotic activity of bortezomib on fresh CD34 + blast cells from patients was similar to that observed on CD34 - blast cells. Importantly, bortezomib was significantly more active than doxorubicin in the immature CD34+ cells, while there were no differences in its action on CD34- cells. [Conclusions]: Bortezomib induces apoptosis in acute myeloid leukemia cells in vitro. Whether this drug might be useful in the treatment of patients with acute myeloid leukemia can be established only in ad hoc clinical trials. ©2008 Ferrata Storti Foundation., We thank Johnson and Johnson Pharmaceutical Research and Development (JJPRD).

This is an open-access paper.-- PETHEMA Group: et al., This phase Ib/II trial combined the pan-deacetylase inhibitor panobinostat with chemotherapy followed by panobinostat maintenance in elderly patients with newly diagnosed acute myeloid leukemia. Patients with prior history of myelodysplastic syndrome were excluded and 38 evaluable patients were included in the study (median age: 71 years; range: 65–83). Study patients received an induction with idarubicin (8 mg/m2 iv days 1–3) plus cytarabine (100 mg/m2 iv days 1–7) plus panobinostat po at escalating doses (days 8, 10, 12, 15, 17 and 19) that could be repeated in non-responding patients. Patients achieving complete remission received a consolidation cycle with the same schema, followed by panobinostat maintenance (40 mg po 3 days/week) every other week until progression. Thirty-one patients were treated at the maximum tolerated dose of panobinostat in the combination (10 mg) with good tolerability. Complete remission rate was 64% with a time to relapse of 17.0 months (12.8–21.1). Median overall survival for the whole series was 17 months (5.5–28.4). Moreover, in 4 of 5 patients with persistent minimal residual disease before maintenance, panobinostat monotherapy reduced its levels, with complete negativization in two of them. Maintenance phase was well tolerated. The most frequent adverse events were thrombocytopenia (25% grades 3/4), and gastrointestinal toxicity, asthenia and anorexia (mainly grades 1/2). Five patients required dose reduction during this phase, but only one discontinued therapy due to toxicity. These results suggest that panobinostat is one of the first novel agents with activity in elderly acute myeloid leukemia patients, and suggest further investigation is warranted, particularly in the context of maintenance therapy. This trial is registered at clinicaltrials.gov identifier: 00840346., This work was partially supported by a grant from the Spanish ISCIII (FIS PI12/02321).

Stringent complete response (sCR) criteria are used in multiple myeloma as a deeper response category compared with CR, but prospective validation is lacking, it is not always clear how evaluation of clonality is performed, and is it not known what the relative clinical influence is of the serum free light chain ratio (sFLCr) and bone marrow (BM) clonality to define more sCR. To clarify this controversy, we focused on 94 patients that reached CR, of which 69 (73%) also fulfilled the sCR criteria. Patients with sCR displayed slightly longer time to progression (median, 62 vs 53 months, respectively; P = .31). On analyzing this contribution to the prognosis of sFLCr or clonality, it was found that the sFLCr does not identify patients in CR at distinct risk; by contrast, low-sensitive multiparametric flow cytometry (MFC) immunophenotyping (2 colors), which is equivalent to immunohistochemistry, identifies a small number of patients (5 cases) with high residual tumor burden and dismal outcome; nevertheless, using traditional 4-color MFC, persistent clonal BM disease was detectable in 36% of patients, who, compared with minimal residual disease-negative cases, had a significantly inferior outcome. These results show that the current definition of sCR should be revised.

This is an open-access article distributed under the terms of the Creative Commons Attribution License., Currently, the lack of a universal and specific marker of clonality hampers the diagnosis and classification of chronic expansions of natural killer (NK) cells. Here we investigated the utility of flow cytometric detection of aberrant/altered NK-cell phenotypes as a surrogate marker for clonality, in the diagnostic work-up of chronic lymphoproliferative disorders of NK cells (CLPD-NK). For this purpose, a large panel of markers was evaluated by multiparametric flow cytometry on peripheral blood (PB) CD56 NK cells from 60 patients, including 23 subjects with predefined clonal (n = 9) and polyclonal (n = 14) CD56 NK-cell expansions, and 37 with CLPD-NK of undetermined clonality; also, PB samples from 10 healthy adults were included. Clonality was established using the human androgen receptor (HUMARA) assay. Clonal NK cells were found to show decreased expression of CD7, CD11b and CD38, and higher CD2, CD94 and HLADR levels vs. normal NK cells, together with a restricted repertoire of expression of the CD158a, CD158b and CD161 killer-associated receptors. In turn, NK cells from both clonal and polyclonal CLPD-NK showed similar/overlapping phenotypic profiles, except for high and more homogeneous expression of CD94 and HLADR, which was restricted to clonal CLPD-NK. We conclude that the CD94/HLADR phenotypic profile proved to be a useful surrogate marker for NK-cell clonality., This work has been partially supported by the following grants: FIS 02/1244-FEDER, DTS 15/00119-FEDER, RTICC RD06/0020/0035-FEDER and RTICC RD12/0036/0048-FEDER from the Fondo de Investigación Sanitaria, Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain; SA103/03 and SA079U14 from the Consejería de Educación, Junta de Castilla y León, Valladolid, Spain. The research activities of the EuroFlow Consortium were supported by the European Commission (grant STREP EU-FP6, LSHB-CT-2006–018708, entitled ‘Flow cytometry for fast and sensitive diagnosis and follow-up of hematological malignancies’).

In recent years, several studies on large series of multiple myeloma (MM) patients have demonstrated the clinical utility of flow cytometry monitoring of minimal residual disease (flow-MRD) in bone marrow (BM), for improved assessment of response to therapy and prognostication. However, disturbing levels of variability exist regarding the specific protocols and antibody panels used in individual laboratories. Overall, consensus exists about the utility of combined assessment of CD38 and CD138 for the identification of BM plasma cells (PC); in contrast, more heterogeneous lists of markers are used to further distinguish between normal/reactive PCs and myeloma PCs in the MRD settings. Among the later markers, CD19, CD45, CD27, and CD81, together with CD56, CD117, CD200, and CD307, have emerged as particularly informative; however, no single marker provides enough specificity for clear discrimination between clonal PCs and normal PCs. Accordingly, multivariate analyses of single PCs from large series of normal/reactive vs. myeloma BM samples have shown that combined assessment of CD138 and CD38, together with CD45, CD19, CD56, CD27, CD81, and CD117 would be ideally suited for MRD monitoring in virtually every MM patient. However, the specific antibody clones, fluorochrome conjugates and sources of the individual markers determines its optimal (vs. suboptimal or poor) performance in an eight-color staining. Assessment of clonality, via additional cytoplasmic immunoglobulin (CyIg) κ vs. CyIgλ evaluation, may contribute to further establish the normal/reactive vs. clonal nature of small suspicious PC populations at high sensitivity levels, provided that enough cells are evaluated.

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License.-- et al., This follow-up extension of a randomised phase II study assessed differences in long-term outcomes between bortezomib-thalidomide-dexamethasone (VTD) and VTD-cyclophosphamide (VTDC) induction therapy in multiple myeloma. Newly diagnosed patients (n = 98) were randomised 1:1 to intravenous bortezomib (1·3 mg/m2; days 1, 4, 8, 11), thalidomide (100 mg; days 1-21), and dexamethasone (40 mg; days 1-4, 9-12), with/without cyclophosphamide (400 mg/m2; days 1, 8), for four 21-day cycles before stem-cell mobilisation/transplantation. After a median follow-up of 64·8 months, median time-to-next therapy was 51·8 and 47·9 months with VTD and VTDC, respectively. Type of subsequent therapy was similar in both arms. After adjusting for asymmetric censoring, median time to progression was not significantly different between VTD and VTDC [35·7 vs. 34·5 months; Hazard ratio (HR) 1·26, 95% confidence interval: 0·76-2·09; P = 0·370]. Five-year survival was 69·1% and 65·3% with VTD and VTDC, respectively. When analysed by minimal residual disease (MRD) status, overall survival was longer in MRD-negative versus MRD-positive patients with bone marrow-confirmed complete response (HR 3·66, P = 0·0318). VTD induction followed by transplantation provides long-term disease control and, consistent with the primary analysis, there is no additional benefit from adding cyclophosphamide. This study was registered at ClinicalTrials.gov (NCT00531453)., This study was supported by research funding from Janssen Research & Development.

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al., Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare subtype of leukemia/lymphoma, whose diagnosis can be difficult to achieve due to its clinical and biological heterogeneity, as well as its overlapping features with other hematologic malignancies. In this study we investigated whether the association between the maturational stage of tumor cells and the clinico-biological and prognostic features of the disease, based on the analysis of 46 BPDCN cases classified into three maturation-associated subgroups on immunophenotypic grounds. Our results show that blasts from cases with an immature plasmacytoid dendritic cell (pDC) phenotype exhibit an uncommon CD56- phenotype, coexisting with CD34+ non-pDC tumor cells, typically in the absence of extramedullary (e.g. skin) disease at presentation. Conversely, patients with a more mature blast cell phenotype more frequently displayed skin/extramedullary involvement and spread into secondary lymphoid tissues. Despite the dismal outcome, acute lymphoblastic leukemia-type therapy (with central nervous system prophylaxis) and/or allogeneic stem cell transplantation appeared to be the only effective therapies. Overall, our findings indicate that the maturational profile of pDC blasts in BPDCN is highly heterogeneous and translates into a wide clinical spectrum -from acute leukemia to mature lymphoma-like behavior-, which may also lead to variable diagnosis and treatment., This work was supported by grants RD06/0020/0035 and RD12/0036/0048 from RETICS (Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain and Fondos FEDER) and grant EDU/878/2004 from Junta de Castilla y León and Fondo Social Europeo.

We explored the ability of the proteasome inhibitor bortezomib, which prevents nuclear factor kappaB (NF-kappaB) activation, to block T-cell activation, proliferation, and survival within alloreactive compared with resting T cells. For this purpose, T cells were stimulated with PHA, alphaCD3/alphaCD28, or allogeneic dendritic cells or through mixed lymphocyte cultures. NF-kappaB expression increased in activated T lymphocytes compared with resting T cells. Of interest, the higher the NF-kappaB expression, the more intense the proliferative blockade induced by bortezomib. Moreover, after mixed lymphocyte reaction (MLR) cultures, alloreactive T cells were 2 logs more sensitive to bortezomib-induced apoptosis than the resting T-cell counterpart. This effect was due to a selective induction of apoptosis among activated T cells that was related to caspase activation and cleavage of the antiapoptotic bcl-2 protein and was partially abolished by the addition of the pancaspase inhibitor Z-VAD-FMK. In addition, after secondary MLR, the number of activated T cells was significantly reduced among T lymphocytes previously cultured with bortezomib when cells from the same donor were used as stimulating cells. By contrast, when third-party donor cells were used as stimulating cells, no significant differences were observed between T lymphocytes previously exposed or not to the drug, indicating a highly specific depletion of T lymphocytes alloreactive against primary donor antigens. The addition of bortezomib decreased not only the proliferation and viability of activated T lymphocytes but also the levels of IFNgamma and IL-2, which were significantly decreased among activated T cells cultured with bortezomib at doses ranging from 10 to 100 nM. In conclusion, at concentrations reached in the clinical setting, bortezomib induces selective apoptosis and decreases Th1 response among alloreactive T lymphocytes while it barely affects unstimulated T cells. These results establish the basis for the clinical use of bortezomib in the management of graft-versus-host disease (GVHD).

We evaluated the incidence of trisomy 11 in acute myeloblastic leukemia (AML) and its correlation with the most relevant clinical, biological, and immunophenotypic disease characteristics in a total of 399 consecutive AML patients. Trisomy 11 was found in 15 patients (3.8%), in 3 of them as the sole abnormality. Median age was 68 years (range 48-87); 87% of patients were older than 60 years. Seven patients displayed multilineage dysplasia. Cytogenetics showed an association with trisomy 8 in six patients, and in five cases with a del(5q); nine patients had complex karyotypes. In all cases, in situ hybridization studies revealed three copies of the MLL gene, but no rearrangements or tandem duplications of MLL. Immunophenotypic analysis of blast cells showed a constant immature immunophenotypic profile with CD34 or CD117 expression (or both) in all cases analyzed. The complete remission rate was 43%; median survival time was only 2 months.

Since graft-versus-leukemia (GVL) is the main weapon for disease eradication after reduced intensity conditioning (RIC) allogeneic SCT, the availability of sensitive and specific techniques to monitor changes in tumor load after transplant are especially helpful. These minimal residual disease techniques would allow an early intervention in the event of low tumor burden, for which immunotherapy is highly effective. Some authors have found an association between persistence of MRD, mixed chimerism and risk of relapse. Nevertheless, data from the literature remain contradictory and further correlations should be established, especially in RIC transplants. In this study we have analyzed the impact of MRD and chimerism monitoring on the outcome of 34 patients undergoing RIC allogeneic SCT who were considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions. At day +100 25 (75%) patients reached complete remission (CR), there were five (15%) partial responses and three patients progressed. Incidence of grade 2-4 aGVHD and extensive cGVHD were 35% and 58%, respectively. Sixteen percent of patients developing aGVHD relapsed as compared to 47% in those without aGVHD (P = 0.03) and also 10% of patients developing cGVHD relapsed as compared to 50% relapses in those without cGHVD (P = 0.03). Four patients (12%) died due to early (n = 1) and late (n = 3) transplant-related mortality. After a median follow-up of 15 months, 24 out of the 34 patients remain alive. Projected overall survival and disease-free survival at 3 years are 68% and 63%, respectively. Early chimerism analysis showed 67% of patients with complete chimerism (CC) in bone marrow (BM), 86% in peripheral blood (PB), 89% in granulocytes and 68% in T lymphocytes. On day +100, these figures were 68%, 79%, 90% and 73%, respectively, and on day +180 there were 83% patients with CC in BM, 100% in PB, 100% in granulocytes and 100% in T lymphocytes. We observed a trend to a higher incidence of relapse in patients with mixed chimerism (MC) as compared to patients with CC. MRD monitoring by flow cytometry and/or RT-PCR analysis was performed in 23 patients. MRD assessment on days +21 to +56 after transplant allowed identification of patients at risk of relapse. In this sense, seven out of 12 patients (58.3%) who had positive MRD on days +21 to +56 relapsed as compared to none out of 11 patients who had negative MRD (P = 0.002). Of the seven patients with criteria to monitor MRD who relapsed after transplant, all but one remained MRD positive until relapse. By contrast, 10 patients remained MRD negative and all of them are in continuous CR. In nine additional patients, persistence of MRD or mixed chimerism was observed after transplant and withdrawal of cyclosporin with or without DLI was performed. Only two out of these nine patients relapsed. MRD clearance was preceded by CC and GVHD. In conclusion, in our study we found that RIC allogeneic transplantation can be used in patients considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions with both low toxicity and low transplant-related mortality. Simultaneous studies of both chimerism and MRD are a useful tool in order to predict risk of relapse in patients undergoing RIC transplants and so can be helpful for individualizing treatment strategies after transplant.

The distinction between IgM monoclonal gammopathy of undetermined significance (MGUS), asymptomatic Waldenstrom's macroglobulinemia (WM; aWM), and symptomatic WM (sWM) relies on two features: the presence of infiltration by lymphoplasmacytic lymphoma in the bone marrow (BM) biopsy and the existence of signs or symptoms attributable to the disease. Nevertheless, some patients lack a BM biopsy or it is not conclusive for diagnosis. In this study we have investigated 94 patients with IgM monoclonal gammopathies, in which a BM trephine biopsy and morphological and flow cytometry (FCM) evaluation of BM aspirate were available at diagnosis. We found a clear correlation between BM infiltration of B-lymphocytes assessed by morphology and by FCM with a Pearson correlation of 0.62 (P

We have estimated the pharmacological sensitivity and synergism of 125 individual patient samples for all drugs and combination treatments for acute myeloid leukemia in the context of the overall patient population. Each ex vivo pharmacological profile identifies drugs and treatments for which the patient's malignant cells are particularly sensitive or resistant, assisting in the selection of individualized treatments. Background: We have evaluated the ex vivo pharmacology of single drugs and drug combinations in malignant cells of bone marrow samples from 125 patients with acute myeloid leukemia using a novel automated flow cytometry-based platform (ExviTech). We have improved previous ex vivo drug testing with 4 innovations: identifying individual leukemic cells, using intact whole blood during the incubation, using an automated platform that escalates reliably data, and performing analyses pharmacodynamic population models. Patients and Methods: Samples were sent from 24 hospitals to a central laboratory and incubated for 48 hours in whole blood, after which drug activity was measured in terms of depletion of leukemic cells. Results: The sensitivity of single drugs is assessed for standard efficacy (E-MAX) and potency (EC50) variables, ranked as percentiles within the population. The sensitivity of drug-combination treatments is assessed for the synergism achieved in each patient sample. We found a large variability among patient samples in the dose-response curves to a single drug or combination treatment. Conclusion: We hypothesize that the use of the individual patient ex vivo pharmacological profiles may help to guide a personalized treatment selection.

Early response to therapy is one of the most important prognostic factors in acute leukemia. It is hypothesized that early immunophenotypical evaluation may help identify patients at high risk for relapse from those who may remain in complete remission (CR). Using multiparametric flow cytometry, the level of minimal residual disease (MRD) was evaluated in the first bone marrow (BM) in morphologic CR obtained after induction treatment from 126 patients with acute myeloid leukemia (AML) who displayed aberrant phenotypes at diagnosis. Based on MRD level, 4 different risk categories were identified: 8 patients were at very low risk (fewer than 10−4 cells), and none have relapsed thus far; 37 were at low risk (10−4 to 10−3 cells); and 64 were at intermediate risk (fewer than 10−3 to 10−2 cells), with 3-year cumulative relapse rates of 14% and 50%, respectively. The remaining 17 patients were in the high-risk group (more than 10−2 residual aberrant cells) and had a 3-year relapse rate of 84% (P = .0001). MRD level not only influences relapse-free survival but also overall survival (P = .003). The adverse prognostic impact was also observed when M3 and non-M3 patients with AML were separately analyzed, and was associated with adverse cytogenetic subtypes, 2 or more cycles to achieve CR, and high white blood cell counts. Multivariate analysis showed that MRD level was the most powerful independent prognostic factor, followed by cytogenetics and number of cycles to achieve CR. In conclusion, immunophenotypical investigation of MRD in the first BM in mCR obtained after AML induction therapy provides important information for risk assessment in patients with AML.

Introduction: Current recommendations for the treatment of AML in newly diagnosed elderly patients (≥ 65 years) include different therapeutic options (intensive or semi-intensive chemotherapy, low-dose chemotherapy, hypomethylating agents, and supportive care). Regardless of the selected treatment, the results are disappointing because of low overall survival (OS) rates and significant toxicity. Objectives: The primary objective of FLUGAZA trial is to compare the 1-year-OS in 350 patients aged ≥ 65 years diagnosed with AML assigned to azacytidine (n=175) or FLUGA (n=175) arms. Here we present the results of a pre-planned interim safety analysis for both outpatient treatment regimens. Methods Inclusion criteria: Patients diagnosed with de novo or secondary AML according to WHO classification (except for APL), previously untreated, age ≥ 65 years, ECOG 25 x109/L. Concomitant use of hydroxyurea was allowed in the AZA arm if WBC was between 15 and 50 x109/L. In patients with more than 50 x109/L WBC assigned to the AZA arm, the first induction cycle was FLUGA. An interim analysis to assess myelotoxicity, early mortality and response rate was planned in the trial when the last of the first 100 randomized patients completed the first 3 induction cycles. Results: From October 2014 to April 2016, 162 patients were enrolled in 26 Spanish centers from the PETHEMA group. Of them, 22 patients were screen failure and 16 patients did not receive the assigned treatment. The first 100 patients treated were analyzed (58 patients were assigned to AZA arm and 42 to FLUGA arm). Baseline characteristics are shown in Table 1. Median age was 75 [65;90] years in AZA arm vs. 77 [65;88] years in FLUGA arm; 36 (62%) vs. 19 (45%) males. Five patients from AZA arm (n=58) received the first cycle of FLUGA because of WBC > 50 x109/L. Outcomes: overall response rate (CR+CRu+PR) based on the best response accumulated with 3 cycles of treatment was 62% in the AZA arm and 57% in the FLUGA arm. CR+CRu was achieved in 14 patients (24%) from AZA arm and 15 (36%) from FLUGA arm. Early mortality rate (8 weeks) was 14% in AZA and 22% in FLUGA arm. Toxicities: there were no differences in hospitalization and non-hematological ≥ G3 serious adverse events (SAEs) between both arms. Overall, 71 patients (71%), 61 out of 79 (77%) vs. 41 out of 64 (64%) patients, developed neutropenia (< 0.5 x x109/L) after C1, C2 and C3, respectively. Median duration of neutropenia in the AZA arm was 14 days (6;40), 21 days (4;95) and 18 days (1;45) after in C1, C2 and C3, respectively, vs. 15 days (4;33), 15 days (3;36) and 20 days (7;41) after C1, C2 and C3, respectively, in the FLUGA arm (no statistically significant differences). Eighty-one (81%), 55 out of 79 (70%) vs. 40 out of 64 (62%) patients, developed thrombocytopenia (< 50 x109/L) after C1, C2 and C3, respectively. Median duration of thrombocytopenia was 14 days (5;29) after C1, 18 days (4;88) after C2 and 14 days (7;25) after C3 in the AZA arm; vs. 16 (3;63), 20 (6;42) and 13 days (7;56) after C1, C2 and C3, respectively, in the FLUGA arm (NS). Conclusions: Outpatient treatment with AZA or FLUGA was feasible. Both treatment arms showed a similar rate of early mortality and relatively low CR/CRu rates. The study is currently enrolling patients until the planned accrual goal (350 patients) to assess the primary end-point (1-year OS). The study is registered at www.ClinicalTrials.gov as NCT02319135. Disclosures No relevant conflicts of interest to declare.

INTRODUCTION: Endoscopic and transbrochial ultrasound-guided fine needle aspiration techniques facilitate the sample acquisition process from the deep intrathoracic or intra-abdominal lymph nodes and masses, for cytological analysis, without requiring surgical procedures. These techniques minimize patient's discomfort, are cost-saving and can be applicable as the first diagnostic approach. Accurate analysis of the aspirate material is the key to achieve a correct diagnosis and to conduct further management. The aim of our study is to determine the utility of multiparametric flow cytometry (FC) in comparison to that of cytomorphology (CM) in analyzing samples obtained by endoscopic techniques as screening for hematological malignancies. METHODS: We retrospectively analyzed the results of 166 samples routinely submitted to hematology FC laboratory, obtained by transluminal puncture of adenopathies or masses (124 transbronchial and 42 endoscopic fine needle aspirations) for the screening of hematological neoplasia. All the samples were processed within the first four hours after obtainment. Eight-color, well-standardized panel was used for the screening of lymphoproliferative syndrome (B screening: Kappa-FITC/ Lambda-PE / CD5-PerCP-Cy5.5/ CD19-PE-Cy7/ CD10-APC/ CD38-APCH7/ CD20-V450 /CD45-OC515; and T screening CD2-FITC/ CD5-PE / CD8-PerCP-Cy5.5/ CD7-PE-Cy7/ CD56-APC/ CD4-APCH7/ CD3-V450 /CD45-OC515). At least 1x 10(6) events were acquired by FACSCanto II (BD Biosciences, San Jose, USA). The data was analyzed with the Infinicyt software (Cytognos SL, Spain). Meanwhile, cytomorphology analysis was performed independently by the Pathology department on samples obtained from the same procedure at the same time, with additional immunochemical staining depending on the findings. Finally, results of both techniques were compared to each other and also with the final diagnosis based on the availability of a diagnostic biopsy and the information extracted from clinical history. Statistical analyses were performed using SPSS v20.0 (SPSS Inc., IL USA). RESULTS Comparing the number of evaluable samples using both techniques, FC was more reliable, since 90% (150/166) of the total samples could be evaluated by FC, and only 74% (123/166) were considered evaluable by CM (due to necrosis or hemorrhagic cellularity). Using FC hematological neoplasms were identified in 13% of the total series (22/166): 18 Non Hodgkin lymphoma (NHL) and 4 Multiple Myeloma (MM). In most of the samples (71%; 119/166), the FC approach for screening of lymphoproliferative disorders was negative, and in 9 cases (5%) this approach suggested the presence of a non-hematological neoplasia. Considering CM, although this technique was as useful as FC for the identification of plasma cell dyscrasia identification (4 MM cases detected), it was less useful for NHL diagnosis, detecting only 33% (6/18) of the total number of NHL cases that had been detected by FC. However, CM was more useful for the identification of Hodgkin's Lymphoma (3%; 5/166) and non-hematological neoplasms (14% of carcinomas; 24/166), being the rest of the evaluable samples classified as inflammatory yield (50%; 84/166). In order to reach the definitive final diagnosis, in 66 cases (40%; 66/166) another procedure involving surgery (n= 55) or needle biopsy (n=11) was performed. Eleven new NHL cases were identified, and 8 of these 11 cases were considered as not evaluable for the FC analysis performed in the previous sample, due to low cell viability. In addition, 5 new HL and 10 new carcinoma cases were identified, not diagnosed in previous FNA Cytology. CONCLUSION: Our study of showed that multiparametric FC is more sensitive than CM to diagnose of NHL, while CM is more useful to diagnose solid neoplasms in the analysis of the samples obtained from endoscopic and transbrochial ultrasound-guided FNA technique. Therefore, both techniques should be considered as complementary for the evaluation of these deep thoracic and abdominal nodes or masses. In addition, around 40% of cases require a new biopsy to reach definitive diagnosis. Disclosures Martín: Sevier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Del Cañizo:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansen-Cilag: Membership on an entity's Board of Directors or advisory committees, Research Funding; Arry: 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.

The flow cytometric detection of minimal residual disease (MRD) in precursor-B-acute lymphoblastic leukemias (precursor-B-ALL) mainly relies on the identification of minor leukemic cell populations that can be discriminated from their normal counterparts on the basis of phenotypic aberrancies observed at diagnosis. This technique is not very complex, but discordancies are frequently observed between laboratories, due to the lack of standardized methodological procedures and technical conditions. To develop standardized flow cytometric techniques for MRD detection, a European BIOMED-1 Concerted Action was initiated with the participation of laboratories from six different countries. The goal of this concerted action was to define aberrant phenotypic profiles in a series of 264 consecutive de novo precursor-B-ALL cases, systematically studied with one to five triple-labelings (TdT/CD10/CD19, CD10/CD20/CD19, CD34/CD38/CD19, CD34/CD22/CD19 and CD19/CD34/CD45) using common flow cytometric protocols in all participating laboratories. The use of four or five triple-stainings allowed the identification of aberrant phenotypes in virtually all cases tested (127 out of 130, 98%). These phenotypic aberrancies could be identified in at least two and often three triple-labelings per case. When the analysis was based on two or three triple-stainings, lower incidences of aberrancies were identified (75% and 81% of cases, respectively) that could be detected in one and sometimes two triple-stainings per case. The most informative triple staining was the TdT/CD10/CD19 combination, which enabled the identification of aberrancies in 78% of cases. The frequencies of phenotypic aberrations detected with the other four triple-stainings were 64% for CD10/CD20/CD19, 56% for CD34/CD38/CD19, 46% for CD34/CD22/CD19, and 22% for CD19/CD34/CD45. In addition, cross-lineage antigen expression was detected in 45% of cases, mainly coexpression of the myeloid antigens CD13 and/or CD33 (40%). Parallel flow cytometric studies in different laboratories finally resulted in highly concordant results (>90%) for all five antibody combinations, indicating the high reproducibility of our approach. In conclusion, the technique presented here with triple-labelings forms an excellent basis for standardized flow cytometric MRD studies in multicenter international treatment protocols for precursor-B-ALL patients.

The aim of the present study was to assess which factors influence hematopoietic function long term after transplantation. For this purpose, we have analyzed a series of 79 patients who underwent autologous transplantation. None of them received any further chemotherapy or radiotherapy after transplant. All patients were disease-free 1 year after autologous transplantation. Late impairment of hematopoietic function was defined as the presence of non-transient peripheral blood cytopenias, detected 6 and 12 months after autografting. Before transplantion, 38.7% of patients showed peripheral blood cytopenias. Six and 12 months after transplantation, cytopenias presented in 44.2% and 42.4% of patients, respectively. Cases displaying cytopenias 6 months after transplantation had received a significantly lower dose of CFU-GM and CD34 + cells than patients without cytopenias (P = 0.012 and P = 0.04, respectively). The same correlation, with even higher statistical significance, was observed 12 months after transplant (P = 0.007 and P = 0.005). Alkylating agents and radiotherapy administered prior to transplantation and age did not seem to influence the presence of permanent cytopenias. The incidence did not vary significantly according to the stem cell source (bone marrow or peripheral blood). The number of CFU-GM and CD34 + cells infused was the most important factor for maintenance of adequate hematopoiesis.

Spanish Myeloma Group (GEM) and Grupo Castellano-Leones de Gammapatias Monoclonales, cooperative study groups: et al., Multiple myeloma remains largely incurable. However, a few patients experience more than 10 years of relapsefree survival and can be considered as operationally cured. Interestingly, long-term disease control in multiple myeloma is not restricted to patients with a complete response, since some patients revert to having a profile of monoclonal gammopathy of undetermined significance. We compared the distribution of multiple compartments of lymphocytes and dendritic cells in the bone marrow and peripheral blood of multiple myeloma patients with long-term disease control (n=28), patients with newly diagnosed monoclonal gammopathy of undetermined significance (n=23), patients with symptomatic multiple myeloma (n=23), and age-matched healthy adults (n=10). Similarly to the patients with monoclonal gammopathy of undetermined significance and symptomatic multiple myeloma, patients with long-term disease control showed an expansion of cytotoxic CD8 + T cells and natural killer cells. However, the numbers of bone marrow T-regulatory cells were lower in patients with long-term disease control than in those with symptomatic multiple myeloma. It is noteworthy that B cells were depleted in patients with monoclonal gammopathy of undetermined significance and in those with symptomatic multiple myeloma, but recovered in both the bone marrow and peripheral blood of patients with long-term disease control, due to an increase in normal bone marrow B-cell precursors and plasma cells, as well as pre-germinal center peripheral blood B cells. The number of bone marrow dendritic cells and tissue macrophages differed significantly between patients with long-term disease control and those with symptomatic multiple myeloma, with a trend to cell count recovering in the former group of patients towards levels similar to those found in healthy adults. In summary, our results indicate that multiple myeloma patients with long-term disease control have a constellation of unique immune changes favoring both immune cytotoxicity and recovery of B-cell production and homing, suggesting improved immune surveillance., This work was supported by the Cooperative Research Thematic Network (RTICCs; RD06/0020/0006 and G03/136), Instituto de Salud Carlos III/ Subdirección General de Investigación Sanitaria (FIS: PI060339; 06/1354; 02/0905; 01/0089/01-02; PS09/01897/01370) and Consejeria de Educacion (GR37) and Consejería de Sanidad, Junta de Castilla y León, Valladolid, Spain (557/A/10). The authors also thank the Fundación Carolina-BBVA for supporting and promoting the exchange of medical researchers from Latin America to Spain.

Interleukin-6 (IL-6), a product of bone marrow stromal cells (BMSCs), is a growth factor for multiple myeloma (MM) cells. Transforming growth factor-beta1 (TGF-beta1) is also produced by BMSCs and can regulate IL- 6 secretion by several tissues, including BMSCs. The present study was designed to characterize in vitro tumor growth regulation by TGF-beta1 in MM. Sorted CD38+CD45RA- MM cells secreted significantly more TGF- beta1 (8.2 +/- 2.0 ng/mL) than peripheral blood mononuclear cells (P < .001), splenic B cells (P < .001), and CD40 ligand (CD40L) pretreated B cells (P < .05). TGF-beta1 secretion by MM-BMMCs (3.8 +/- 0.9 ng/mL) was significantly greater than by N-BMMCs (1.2 +/- 0.1 ng/mL, P < .001). MM-BMSCs also secreted significantly more TGF-beta1 (6.6 +/- 2.5 ng/mL, n = 11) than N-BMSCs (4.4 +/- 0.6 ng/mL, P < .02, n = 10) and N- BMSC lines (3.9 +/- 0.2 ng/mL, P < .02, n = 6). TGF-beta1 secretion was correlated with IL-6 secretion in MM-BMSCs. Anti-TGF-beta1 monoclonal antibody both blocked IL-6 secretion by BMSCs and inhibited the increments in IL-6 secretion by BMSCs induced by MM cell adhesion. Moreover, exogenous TGF-beta1 upregulated IL-6 secretion by MM-BMSCs, normal BMSCs, and CD38+ CD45RA- MM cells, as well as tumor cell proliferation. This is in contrast to the inhibitory effect of TGF- beta1 on proliferation and Ig secretion of normal splenic B cells. Finally, retinoblastoma proteins (pRB) are constitutively phosphorylated in MM cells; TGF-beta1 either did not alter or increased pRB phosphorylation. pRB are dephosphorylated in splenic B cells and phosphorylated in CD40L triggered B cells in contrast to its effects on MM cells, TGF-beta1 decreased phosphorylation of pRB in CD40L treated B cells. These results suggest that TGF-beta1 is produced in MM by both tumor cells and BMSCs, with related tumore cell growth. Moreover, MM cell growth may be enhanced by resistance of tumor cells to the inhibitory effects of TGF-beta1 on normal B-cell proliferation and Ig secretion.

e18510Background: The aim of this study is to determine the ability of Vivia's novel test (based on studying the ex-vivo sensitivity to drugs) to predict the complete remission (CR) rates after ind...

et al. PETHEMA/GEM (Programa para el Estudio de la Terapéutica en Hemopatías Malignas/Grupo Español de Mieloma) Cooperative Study Groups., The achievement of complete response (CR) after high-dose therapy/autologous stem cell transplantation (HDT/ASCT) is a surrogate for prolonged survival in multiple myeloma; however, patients who lose their CR status within 1 year of HDT/ASCT (unsustained CR) have poor prognosis. Thus, the identification of these patients is highly relevant. Here, we investigate which prognostic markers can predict unsustained CR in a series of 241 patients in CR at day +100 after HDT/ASCT who were enrolled in the Spanish GEM2000 (n = 140) and GEM2005 < 65y (n = 101) trials. Twenty-nine (12%) of the 241 patients showed unsustained CR and a dismal outcome (median overall survival 39 months). The presence of baseline high-risk cytogenetics by FISH (hazard ratio 17.3; P = .002) and persistent minimal residual disease by multiparameter flow cytometry at day +100 after HDT/ASCT (hazard ratio 8.0; P = .005) were the only independent factors that predicted unsustained CR. Thus, these 2 parameters may help to identify patients in CR at risk of early progression after HDT/ASCT in whom novel treatments should be investigated., This work was supported by the Cooperative Research Thematic Network (RTICs; RD06/0020/0006, RD06/0020/0005, RD06/0020/0031, RD06/0020/0101, RD06/0020/1056, and G03/136), MM Jevitt, SL Firm, Instituto de Salud Carlos III/Subdirección General de Investigación Sanitaria (FIS: PI060339; 06/1354; 02/0905; 01/0089/01-02; PS09/01 897), and Consejería de Sanidad, Junta de Castilla y León, Valladolid, Spain (557/A/10).

In the present paper a CD38/propidium iodide double staining technique is described which separately assesses the cell cycle distribution of myelomatous plasma cells from that of the residual normal hemopoietic cells. For this purpose, bone marrow (BM) cells from a group of 42 untreated multiple myeloma patients were analyzed. Of these, 23 cases were aneuploid (55%) and 19 diploid (45%). The use of the CD38/propidium iodide double staining method allowed a clear separation between CD38 strong positive cells from the remaining bone marrow populations, cell sorting experiments confirming that plasma cells were almost exclusively contained in the former fraction where they represented 97 +/- 2% of the total cells sorted. In all cases, the S-phase in plasma cells and in the remaining normal hemopoietic bone marrow cells was assessed, being higher in normal hemopoietic cells (8.0 +/- 6.3%) than in plasma cells (3.3 +/- 2.6%, P0.002). In addition, there was no correlation between the S-phase of the neoplastic and normal bone marrow cells (r = 0.22; P0.10); this work therefore shows that the assessment of the total proliferative rate of bone marrow samples does not reflect either the proliferation of normal cells or that of neoplastic plasma cells but will depend on the proliferative rate and the percentage of each population within the sample, which can be assessed by the technique described here.

Introduction: Although multiple myeloma (MM) is typically described as an incurable disease, it has been shown in recent years that a small fraction of patients may reach more than 10-years progression-free survival (PFS), which is considered as the minimum threshold to identify patients in "operational cure". However, because of the scarcity of available data there is significant lack of knowledge in MM regarding the frequency of cases attaining operational cure, nor the existence of biomarkers that could prospectively predict such curability. Methods: Herein, we sought to define the frequency as well as the biomarkers predictive of operational cure in a large series of uniformly-treated transplant-eligible patients enrolled in the PETHEMA/GEM2000 protocol (VBMCP/VBAD followed by HDT/ASCT and 2 years of maintenance with interferon and prednisone). Patients' follow-up was updated at the time of abstract submission, and the median follow-up of the series is now of 12-years. We used an automated multiparameter flow cytometric (MFC) classification model focused on the analysis of the bone marrow plasma-cell compartment to identify among newly diagnosed symptomatic MM those with MGUS-like vs. MM-like phenotypic signatures. Minimal residual disease (MRD) was monitored using a first-generation 4-color MFC assay (CD38-FITC / CD56-PE / CD19-PerCPCy5.5 / CD45-APC) with a limit of detection of 10-4. PFS and overall survival (OS) were measured from the time of diagnosis. Results: From a total of 1075 patients enrolled in the GEM2000 protocol, 763 were eligible for this analysis because they either relapsed or died during the first 10-years from diagnosis (n=666; 87%), or remained progression-free and alive for more than 10-yers (n=97; 13%); accordingly, all patients remaining progression-free and alive but for which the follow-up was inferior to 10-years were excluded from the analysis. We then investigated the biomarkers that could help to identify patients reaching operational cure after HDT/ASCT. As compared to the vast majority of cases, patients reaching >10-years PFS (13%) had significantly less frequent anemia (76% vs. 60%, respectively; P=.002), as well as more frequent Durie-Salmon stage IA (14% vs. 6%; P=.004), MGUS-like signature as determined by the automated MFC algorithm (28% vs. 6%; P10-years PFS vs. those who relapsed earlier. On multivariate analysis, only the presence of an MGUS-like signature at baseline (P=.04; HR: 3.9) and MRD-negativity at day+100 after HDT/ASCT (P=.006; HR: 6.3) emerged as independent predictive markers for >10-years PFS; anemia, Durie-Salmon and CR status were not retained in the logistic regression model. Accordingly, patients with an MFC-defined baseline MGUS-like signature reaching MRD-negativity after HDT/ASCT (n=14) had a median PFS of 10-years and a 10-year OS rate of 79%, which were significantly superior to those observed among cases with MM-like signatures being MRD-negative (n=54) or positive (n=99) after therapy [median PFS of 6 and 3 years (P Conclusions: We demonstrated that operational cure (i.e.: >10-years PFS) was possible for 13% of transplant-eligible MM patients before the era of novel agents. Curability rates were particularly frequent among patients with a benign phenotypic signature at diagnosis and MRD negativity after HDT/ASCT, suggesting a remarkable clinical benefit of attaining deep remissions after intensive treatment for patients with early MM. Disclosures Paiva: Sanofi: Consultancy; Janssen: Consultancy; Millenium: Consultancy; Onyx: Consultancy; BD Bioscience: Consultancy; EngMab AG: Research Funding; Binding Site: Consultancy; Celgene: Consultancy. Puig:The Binding Site: Consultancy; Janssen: Consultancy. Mateos:Takeda: Consultancy; Celgene: Consultancy, Honoraria; Onyx: Consultancy; Janssen-Cilag: Consultancy, Honoraria. San Miguel:Celgene: Honoraria; Bristol-Myers Squibb: Honoraria; Onyx: Honoraria; Sanofi-Aventis: Honoraria; Novartis: Honoraria; Millennium: Honoraria; Janssen-Cilag: Honoraria.

Introduction: Several cooperative MM groups have shown that MRD monitoring may be relevant as biomarker to evaluate the efficacy of different treatment strategies, to support treatment decisions, and to act as surrogate for overall survival (OS) in MM. Because of its wider applicability, a significant fraction of available MRD data has been obtained using MFC that originally, was limited to 4- or 6-colors and measured a limited number of cells. It is assumed that the sensitivity of MFC can increase by usage of ≥8 markers and acquisition of greater cell numbers, but the degree of improved specificity and sensitivity remains unknown. Methods: We aimed at determining the increment in specificity and sensitivity upon transition from first-generation 4-color into a second-generation 8-color MFC assay, by applying new computational tools developed by the EuroFlow consortium in elderly MM patients, enrolled in the GEM2010MAS65 study, for which MRD monitoring was performed with an 8-color monoclonal antibody combination - CD45-PacB/CD138-OC515/CD38-FITC/CD56-PE/CD27-PerCPCy5.5/CD19-PECy7/CD117-APC/CD81-APCH7 - and acquisition of ≥2x106 leukocytes (detection limit: 10-5). Time-to-progression (TTP) and OS were measured from diagnosis. Results: First, we created a reference data file of normal (n=17) and clonal (n=71) plasma cells (PCs) derived from bone marrow samples of healthy individuals and MM patients (Figure 1A) in order to determine the individual contribution of each marker to the discrimination between normal vs. clonal PCs. Principal component analysis (PCA) showed that CD19 ranked as the most significant marker followed by CD56, CD81, CD27, CD117, CD45, forward scatter (FSC), CD38, CD138 and sideward scatter (SSC). Accordingly, the 8-color combination resulted in improved discrimination between normal vs. clonal PCs as compared to the former 4-color approach based only on CD38/CD56/CD19/CD45 (Figure 1B); in fact, CD81, CD27 and CD117 had higher independent value than CD45 in the PCA. Afterwards, we focused on 50 randomly selected MRD-positive patients enrolled in the GEM2010MAS65 study, to compare the performance of an 8- vs. 4-color software-guided classification of MRD cells. PCA based on 8-colors showed that all but two patients were accurately located in the clonal PC reference and outside 1 or 2 standard deviation (SD) curves of the normal PC reference (96% accuracy; Figure 1C); by contrast, using 4-color software-guided classification up to 9 patients became located in the overlapping area between 1 and 2 SD of the normal and clonal PCs references (82% accuracy; Figure 1D). Afterward, we investigated the increment in sensitivity due to the evaluation of 2x106 leukocytes with the second-generation 8-color flow assay instead of the standard 2x105 cells with the first-generation 4-color approach, by determining how many of the 50 MRD-positive patients would turn into MRD-negative if only 2x105 leukocytes had been analyzed (detection limit: 10-4). Interestingly, by reducing the number of visible events to 2x105, our results showed that up to 15 out of the 50 cases (30%) would become wrongly classified as MRD-negative. Then, we investigated the impact in TTP and OS of having MRD levels of 10-5 within a series of 163 patients enrolled in the GEM2010MAS65 and with MRD assessment. Accordingly, 88 cases had detectable MRD levels ≥10-4, 21 patients had persistent MRD at 10-5, and the remaining 54 cases were MRD-negative. Importantly, MRD-positive patients at 10-5 had similar outcome as compared to cases with MRD levels ≥10-4 (both had median TTP of 31 months; 3-year OS rates were 80% and 74%, respectively) and significantly inferior to that of MRD-negative patients [median TTP not reached (P Conclusions: We showed that the transition from a first-generation 4-color into a second-generation 8-color MFC assay that measured ten-times more cells resulted in increased specificity and sensitivity. MRD detection at the 10-5 level is clinically relevant, since it identifies a subset of patients with inferior survival than MRD-negative cases, similar to that of the overall MRD-positive patient population. Figure 1. Figure 1. Disclosures Paiva: Millenium: Consultancy; BD Bioscience: Consultancy; Celgene: Consultancy; Janssen: Consultancy; EngMab AG: Research Funding; Binding Site: Consultancy; Onyx: Consultancy; Sanofi: Consultancy. Puig:Janssen: Consultancy; The Binding Site: Consultancy. Gironella:Celgene Corporation: Consultancy, Honoraria. van Dongen:BD Biosciences (cont'd): Other: Laboratory Services in the field of technical validation of EuroFlow-OneFlow antibody tubes in dried format. The Laboratory Services are provided by the Laboratory of Medical Immunology, Dept. of Immunology, Erasmus MC, Rotterdam, NL; Cytognos: Patents & Royalties: Licensing of IP on Infinicyt software, Patents on EuroFlow-based flowcytometric Diagnosis and Classification of hematological malignancies, Patents on MRD diagnostics, and Patents on PID diagnostics.; Cytognos (continued): Patents & Royalties: Royalty income for EuroFlow Consortium. The Infinicyt software is provided to all EuroFlow members free-of-charge.Licensing of Patent on detection of IgE+ B-cells in allergic diseases. Royalties for Dept. of Immunology, Erasmus MC, Rotterdam, NL; DAKO: Patents & Royalties: Licensing of IP and Patent on Split-Signal FISH. Royalties for Dept. of Immunology, Erasmus MC, Rotterdam, NL; InVivoScribe: Patents & Royalties: Licensing of IP and Patent on BIOMED-2-based methods for PCR-based Clonality Diagnostics.. Royalty income for EuroClonality-BIOMED-2 Consortium ; Immunostep: Patents & Royalties: Licensing of IP and Patents on immunobead-based dection of fusion proteins in acute leukemias and other tumors. Royalties for Dept. of Immunology, Erasmus MC and for EuroFlow Consortium ; BD Biosciences: Other: Educational Services: Educational Lectures and Educational Workshops (+ related travelling costs). The lectures and workshops fully focus on the scientific achievements of the EuroFlow Consortium (No advertisement of products of BD Biosciences). , Patents & Royalties: Licensing of IP and Patent on EuroFlow-based flowcytometric Diagnosis and Classification of hematological malignancies; Royalty income for EuroFlow Consortium.; Roche: Consultancy, Other: Laboratory Services in the field of MRD diagnostics, provided by the Laboratory of Medical Immunology, Dept. of Immunology, Erasmus MC, Rotterdam, NL.. Mateos:Takeda: Consultancy; Onyx: Consultancy; Celgene: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria. San Miguel:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees; Onyx: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees.