ALBERT

Description: Introduction: Allogeneic stem cell transplantation is a potentially curative treatment for patients with high-risk non-Hodgkin lymphoma (NHL). Fludarabine/busulfan based conditioning regimens are widely used in Europe for this purpose. Busulfan dose intensity discriminates between reduced intensity (FB2, 2 days of busulfan at 4 mg/Kg/d per os or 3.2 mg/kg/d iv) and reduced-toxicity myeloablative (FB3/FB4, 3 or 4 days of busulfan at 4 mg/Kg/d per os or 3.2 mg/kg/d iv) conditioning regimens (Bacigalupo, 2009). While some data have been recently published showing some advantages of higher busulfan dose intensity for myeloid malignancies, there is no such data available in the lymphoid setting. Methods: This was a large retrospective study conducted on behalf of the SFGM-TC including all adults allografted in France between January 2004 and December 2014 for NHL (n=378). Clinical data were obtained through ProMISe (Project Manager Internet Server), an internet-based system shared by all French transplantation centers. We aim to compare various outcomes (overall (OS) and lymphoma free (LFS) survivals, relapse incidence (RI), non-relapse mortality (NRM), acute and chronic GVHD) between those who received FB2 (n=277) or FB3/FB4 (n=101) as conditioning regimens. GVHD free relapse free survival (GRFS) was also studied (defined as alive with no previous grade III-IV aGvHD, no moderate or severe chronic GvHD (cGvHD) and no relapse). Results: Both groups were comparable for the following variables: median follow-up (FB2: 24.9 vs FB3/4: 23 months), gender (male 61% vs 53%), disease type (low-grade lymphoma 25% vs 21%, mantle-cell lymphoma 17% vs 13%, high-grade lymphoma 25% vs 21%, T cell lymphoma 32% vs 45%), disease status at transplant (complete remission/very good partial response 64% vs 62%, partial response 28% vs 31%, active disease 8% vs 7%), donor type (sibling 43% vs 49.5%, matched unrelated 56% vs 47), median number of previous courses of treatment (2 vs 2, p=0.44), stem cell source (peripheral blood 96% vs 95%). FB2 patients were significantly older (median 57.3 vs 53.1 years, p=0.07), have been transplanted more recently (median year of transplant: 2011 vs 2010, p=0.001) and have been more previously autografted (69% vs 50.5%, p=0.001). FB3/4 patients have been allotransplanted earlier during the evolution of their disease (median time between diagnosis and allograft 18.2 vs 33.8 months, p=30 months), there were also no significant differences between both groups in terms of OS, LFS, RI or NRM. In multivariate analysis there was a trend for worse outcome using FB3/FB4 regimens (OS: HR 1.46, 95%CI: 0.96-2.23, p=0.07; LFS: HR: 1.43, 95%CI: 0.99-2.06, p=0.05; RI: HR 1.54; 95%CI: 0.95-2.48, p=0.07). These results were also confirmed using a propensity score-matching strategy including 184 FB2 and 98 FB3/4 patients. Conclusion: This large retrospective study showed that reduced toxicity myeloablative fludarabine/busulfan regimens did not improve outcomes of adults allografted for NHL. FB2 conditioning regimen still should be considered as the standard of care conditioning regimen in this setting. To validate these results, prospective studies are needed, like the French prospective trial currently ongoing for myeloid diseases (NCT01985061). Also, new conditioning regimens and post-allograft strategies should be tested to improve outcomes of patients. Disclosures Peffault De Latour: NOVARTIS: Consultancy, Honoraria, Research Funding; PFIZER: Consultancy, Honoraria, Research Funding; ALEXION: Consultancy, Honoraria, Research Funding.

Description: Introduction. [18 F]-Fludarabine is a promising novel positron emission tomography (PET) radiotracer for lymphoid malignancies. The rationale supporting its development is the high selectivity of fludarabine uptake within lymphoid cells irrespective of their cycle activity, and the fluorine atom within the drug, which replaced by a [18 F] confers the positron-emitter property. Pre-clinical studies with [18 F]-fludarabine (Dhilly M et al, Mol Imaging Biol 2014,16:118-26; Hovhannisyan N et al, EJNMMI Res 2015,5:23) showed a marked tumor uptake in lymphoma-bearing mice. The aim of this study was to describe anatomical sites with abnormal [18 F]-fludarabine uptake in patients with B-cell chronic lymphocytic leukemia (B-CLL), in whom [18 F]-FDG PET imaging appears to be less informative than in other lymphoid malignancies. This study was designed as a clinical proof of concept. Methods. [18 F]-Fludarabine was produced according to a method already described (Guillouet S et al, Mol Imaging Biol 2014,16:28-35). [18 F]-Fludarabine PET/CT (Discovery RX VCT 64, GE Healthcare) was performed in 5 patients (51-70 years old) with a diagnosis of B-CLL (according to current recommendations), without suspicion of Richter's syndrome. Successive partial body scans (skull vertex to mid-thigh) were acquired for 250 min after intravenous injection of [18 F]-fludarabine with an activity of 4MBq/kg. PET images were analyzed by drawing volumes of interest (VOI) over the uptake sites on a late scan and projected onto all co-registered scans of the same subject. The intensity of tracer uptake was evaluated with the maximum standardized uptake value (SUVmax). The images of [18 F]-fludarabine PET/CT were visually compared with conventional modalities (high-resolution CT) and [18 F]-FDG PET in one patient. Results. No adverse event was recorded during and after the procedure. In the 5 patients studied, the uptake of [18 F]-fludarabine coincides with sites expected to be involved following conventional clinical and CT scan staging (i.e. lymph nodes, spleen, tonsils). Additionally, [18 F]-fludarabine PET/CT displayed a significant uptake in hematopoietic bone marrow, and unexpected uptake in the medulla of some bones (femur, humerus, sphenoid, calvarium), and in Peyer's patches. SUVmax were significantly greater in involved sites in comparison with normal tissues or organs (Figure 1). Within the involved sites, [18 F]-fludarabine demonstrated a wide range of uptake which would indicate heterogeneity and differing micro-environments. For instance, the most active sites of the case illustrated in Figure 1 (scan period 30-50 min) are lymph nodes (SUVmax 7.4), spleen (SUVmax 6.3) and bone marrow (SUVmax 3.8) with aortic uptake (SUVmax 1.5) as background level. Conclusion. These preliminary results showed a clear specificity of this novel radiotracer for lymphoid tissues. [18 F]-Fludarabine PET/CT appears to be a promising tool for the diagnosis and follow-up of B-CLL. These scans indicate variable activity within proliferation sites, information otherwise not accessible by current non-invasive procedures. Further studies for a more accurate comparison with [18 F]-FDG PET, evaluation of response during and after treatment and correlation with B-CLL prognostic criteria are underway. Figure 2. Figure 2. Disclosures No relevant conflicts of interest to declare.

Description: Background: Allogeneic hematopoietic cell transplantation (alloHCT) is a complex therapy which can induce a multi-factorial cascade of complications, and potentially lead to patient death. The triggering event(s), sequence and severity of such complications can significantly differ between patients, but in many cases, a so-called "multi-organ failure" (MOF) is usually reported as the leading cause of death. However, a patient's clinical course can be very heterogeneous across and within cause-specific mortalities. Moreover, comorbidities present prior to alloHCT carry their own risks and represent additional confounding factors. Therefore, identification of the exact initial trigger or event leading to MOF in alloHCT patients is a critical step towards early intervention and improvement of patients' outcome. The goal of the current study was to establish and identify the exact cause of death in alloHCT patients where MOF was considered to be the main cause of death. Of note, we specifically focused on VOD/SOS because this life-threatening complication has a mortality exceeding 80% in severe cases, ending usually in MOF, and because VOD/SOS has subtle and dynamic evolution features which are not easy to capture, but could be potentially controlled by appropriate therapy (eg. defibrotide). Patients and Methods: For the purpose of this analysis, we randomly identified 241 adult patients (42% female; median age: 50 years; range 19-73) with acute leukemia (72% AML, 25% ALL, 3% other) allografted between 2010 and 2018 from a matched sibling (29%), unrelated (61%) or haploidentical donor (10%). All patients were reported to the EBMT registry to have died from MOF. Karnofsky score at time of alloHCT was 〉90 in 87% of patients. Seventy-three percent of patients underwent transplant in complete remission, and conditioning was myeloablative in 70%. Sixty patients (25%) received VOD/SOS prophylaxis treatment, mainly consisting of ursodiol and/or heparin. Patients' files were reviewed in detail in order to capture all early signs and symptoms which occurred prior to MOF, based on the classical Baltimore criteria, modified Seattle criteria, and/or the newly published EBMT criteria. These criteria included bilirubin levels, the presence of hepatomegaly or painful hepatomegaly, ascites, percentage weight gain, hemodynamic instability, and ultrasound/histologically proven VOD/SOS. Results: Using one or more of the above criteria defining VOD/SOS, we identified a total of 67 (28%) patients for whom VOD/SOS could be considered as the trigger for MOF and the leading cause of death. Interestingly, among these 67 patients, only 22 (33%) were originally reported by the centers as having developed VOD/SOS leading to MOF post-transplant. When comparing the group of 67 patients dying of VOD/SOS-related MOF and the remaining 174 patients dying of MOF not related to VOD/SOS (please see attached table), a multivariate regression analysis identified a significant increase in VOD/SOS incidence (odds ratio 3.9; 95%CI, 2.42-6.33; p

Description: Introduction. Whereas von Willebrand disease is the most common constitutional bleeding disorder, acquired von Willebrand syndrome (AVWS) is rare with an estimated prevalence between 0.04 to 0.5%(1). AVWS has been related in various pathophysiological conditions including cardiovascular diseases such as aortic stenosis, autoimmune and lymphoproliferative disorders. To our knowledge, the prevalence of AVWS in lymphoproliferative disorders has never been investigated. Methods. We conducted an observational monocentric prospective study in Caen university hospital to evaluate the incidence of AVWS in B cell chronic lymphoproliferative disorders (B-CLPD) and characterize its phenotype. Inclusion criteria were the presence of a BCLPD in patients with no personal or family history of bleeding. Every enrolled patients was tested for Biological parameters were measured including closure time, von Willebrand Antigen (VWF:Ag), ristocetin cofactor activity (VWF:RCo) and factor VIII procoagulant activity (FVIII:C). The bleeding phenotype was evaluated using Tossetto bleeding score(2). AVWS was suspected when patients presented a decrease of VWF:Ag and VWF:RCo and/or a VWF:RCo/VWF:Ag below 0.7. Results. A total of 147 patients were included with the following diagnosis: fifty five patients (37%) with chronic lymphocytic leukemia, 48 patients (33%) with monoclonal gammopathies of undetermined significance (MGUS), 22 patients (15 %) with non hodgkin B cell lymphoma, 9 patients (6 %) with multiple myeloma, 4 patients (3 %) with Waldenstrom macroglobulinemia and 9 patients with other B-CLPD. Closure times, with epinephrine and ADP, were prolonged for six patients (6/147, 4.1%) with median levels of VWF:Ag, VWF:RCo, FVIII:C and VWF:RCo/VWF:Ag ratio at 29.5 IU/dL [9-284], 11.4 IU/dL [1-140] , 42.5 [6-204] and 0.3 [0.04-0.84], respectively. Five of these 6 patients had MGUS and 1 patient presented a follicular lymphoma. Serum protein electrophoresis revealed a monoclonal component in 5 patients with a median concentration at 8.45 g/L [4.4-9.1]. Four out of these 6 patients presented mucocutaneous bleedings including menorragia, ecchymoses, epistaxis, gingival bleedings, post-operative bleedings and gastro intestinal bleedings. The median bleeding score of these six patients was 4.5 [-1 – 12]. In four patients, the biological phenotype was a type 2 von Willebrand disease, with decreased VWF:RCo/VWF:Ag ratio (

Description: A high proportion of Ph-positive Acute Lymphoblastic Leukemia (Ph+ ALL) patients still undergo relapses despite the use of Tyrosine Kinase Inhibitors (TKIs) in addition to chemotherapy as frontline therapy. In this leukemia subtype, the role of BCR-ABL1 kinase domain (KD) mutations as a driver of resistance to TKIs has already been documented by previous studies and such mutations have been reported in up to 80% of the patients at relapse. Next-generation sequencing (NGS) has been proposed to characterize these mutations with a higher sensitivity than Sanger. We report here a prospective study aiming at detecting potentially resistant cell populations by NGS in Ph+ ALL patients enrolled in the GRAAPH 2014-trial. Between March 2016 and February 2019, 156 patients aged 18 to 59 years with newly diagnosed Ph+ and/or BCR-ABL1 positive ALL have been included in the GRAAPH 2014 trial (NCT02619630). BCR-ABL1 isoforms were E1A2 69%, B2A2/B3A2 29%, atypical 2%. After a prephase of steroid, treatment consisted of 4 blocks of chemotherapy + nilotinib. 118 patients (76%) underwent allogeneic or autologous stem cell transplantation (SCT). 22 medullary relapses were recorded within a median time of 9 months (range, 2 - 35). Blood and marrow samples harvested at diagnosis, after each treatment block, before and 3 months after SCT, and at relapse, were sequenced if BCR-ABL1/ABL1 ratio were above 0.001. Mutated BCR-ABL1 transcripts were detected by sequencing the KD of BCR-ABL1 transcripts by NGS with a limit of detection (LOD) of 0.03. T315I allele specific oligonucleotide (ASO) droplet digital RT-PCR (ddRT-PCR) with a LOD of 0.0005 was also performed at diagnosis on a subset of 63 patients, including 5 who have subsequently developed a T315I clone. NGS. At diagnosis, no KD mutation was found by NGS in pretreatment samples of 137 patients. During follow-up (FU), only 12 mutations were found by NGS in 7 out of the 88 patients tested (81, 45, 30, 20, 19, 9 after block 1, 2, 3, 4, before and 3 months after SCT, respectively). Mutations were T315I (N=6), Y253H (N=1), E255K (N=2), E255V (N=1), Q252H (N=1), Y253F (N=1). At relapse, 16 mutations were identified by NGS in 12 patients out of the 17 tested (71%). Mutations were T315I (N=7), Y253H (N=n=3), F359V (N=2), E255K (N=1), E255V (N=1), Q252H (N=1), Y253F (N=1). More than 1 mutated clone were present in 2 patients (E255V+T315I+F359V and Y253H+F359V), and a compound mutation was found in 1 patient (Q252H/Y253F). Out of the 7 patients found mutated during FU, 5 have relapsed with a rapid expansion (1 to 3 months) of the mutated clone. One patient harboring a sub-clonal (10%) E255K at MRD1 has relapsed 9 months later without any detectable mutation. One patient identified with 3 mutated clones (E255K 10%, E255V 10%, T315I 80%) underwent SCT and has not relapsed so far. We failed to anticipate expansion of any mutated clone in the 7 remaining patients found mutated at relapse. T315I ASO ddRT-PCR on diagnostic samples. Low-level T315I mutated BCR-ABL1 transcripts (0.00051 to 0.0013) were detected in 14 out of 63 patients (24%) tested. Only one has expanded a T315I clone later on. In the context of the GRAAPH 2014 trial, 71% of the 17 relapses tested so far were associated with BCR-ABL1 KD mutations. Expansion of the mutated clone could have been characterized before the onset of hematological relapses in only 5 out of 12 patients (42%). Unfortunately in these cases, lags between first detection and relapse were very short (1 to 3 months). On the contrary, occurrences of relapses associated with expansion of KD-mutated clones could not have been anticipated in 58%. All mutations identified, including T315I, F359V, E255K/V and Y253F/H, Q252H/Y253F are known for conferring resistance to nilotinib. NGS is a valuable method for KD mutation detection in Ph+ ALL. It allows a quantitative characterization of KD mutations at relapse. However in our hands and in the context of an intensive therapy combining chemotherapy, nilotinib and SCT, its enhanced sensitivity as compared to Sanger (3% vs 20%) does not translate into the capacity of anticipating expansion of KD-mutated clones. Moreover, in this study, NGS did not detect any mutation in pre-therapeutic samples while T315I mutated BCR-ABL1 transcripts were found at low-level in 24% of these samples by ddRT-PCR. However it should be emphasized that when detected, low-level T315I mutated sub-clones present at diagnosis failed to expand in most instances. Disclosures Cayuela: Incyte: Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau. Chalandon:Pfizer: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Incyte Biosciences: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Rousselot:Pfizer: Research Funding. Thomas:PFIZER: Honoraria; ABBVIE: Honoraria; INCYTE: Honoraria; DAICHI: Honoraria. Huguet:Amgen: Honoraria; Servier: Honoraria; Jazz Pharmaceuticals: Honoraria; BMS: Honoraria; Pfizer: Honoraria; Incyte Biosciences: Honoraria; Novartis: Honoraria. Chevallier:Incyte: Consultancy, Honoraria; Jazz Pharmaceuticals: Honoraria; Daiichi Sankyo: Honoraria. Boissel:NOVARTIS: Consultancy. Vey:Novartis: Consultancy, Honoraria; Janssen: Honoraria. Berthon:PFIZER: Other: DISCLOSURE BOARD; JAZZPHARMACEUTICAL: Other: DISCLOSURE BOARD; CELGEN: Other: DISCLOSURE BOARD.

Description: Context. The prognostic value of gene mutations in older AML patients (pts) treated intensively remains unclear. Only one study has explored the role of mutation patterns determined by NGS in older AML pts prospectively treated with various chemotherapies in years 2000-2010 (Eisfeld Leukemia 2018). Methods. Pts older than 60y enrolled in the ALFA-1200 trial (NCT01966497) between 09/2012 and 06/2016 were sequenced with a 37-gene myeloid panel. Pts received one 7+3 course followed by 2 intermediate-dose cytarabine courses. Pts with non-favorable risk were eligible for allogeneic stem cell transplantation (SCT). Variable selection for multivariate analyses was performed by lasso penalized regression including age, gender and log(WBC) as covariates. Results. Sequencing was done in 471 (93%) of the 509 enrolled pts. Median age and WBC count were 68y and 5.3x109/L, respectively (resp). CR (including CRp) was achieved in 341 (72%) pts and 90 underwent RIC-SCT in first CR. With a median follow-up of 25.4 months, median OS was 20.7 months. Pts had a median of 3 mutations (range 1-10). The 17 mostly frequently mutated genes (≥5% of pts, by decreasing frequency: DNMT3A, NPM1, TET2, ASXL1, FLT3, SRSF2, IDH2, RUNX1, NRAS, IDH1, STAG2, BCOR, TP53, PTPN11, U2AF1, EZH2 and KRAS) were retained for prognostic analyses. Genes belonging to a common pathway (eg. NRAS and KRAS) may have divergent prognostic values, preventing biology-informed grouping of mutations. Cytogenetic risk (derived from ELN 2017, Döhner Blood 2017, not considering gene mutations) was favorable (fav), intermediate (int), adverse (adv) and missing in 3%, 72%, 18% and 7% resp. Because of the few pts with fav cytogenetics in our cohort, pts were further grouped into non-adv and adv cytogenetics. CR rates and median OS were 75.6% vs 56.6% and 24.8 vs 9.5 months in pts with non-adv and adv cytogenetics, resp (both p

Description: Patients undergoing treatment for acute lymphoblastic leukemia (ALL) are at risk for thrombosis, in part due to the use of L-asparaginase (L-ASP). Antithrombin (AT) replacement has been suggested to prevent VTE and thus might increase exposure to ASP. We report herein the results of the prophylactic replacement strategy in the pediatric-inspired prospective GRAALL-2005 study. Between 2006 and 2014, 784 adult patients with newly diagnosed Philadelphia-negative ALL were included. The incidence rate of VTE was 16% with 69% of them occurring during induction therapy. Most patients received AT supplementation (87%). After excluding patients who did not receive L-ASP or developed thrombosis before L-ASP, AT supplementation did not have a significant impact on VTE (8% versus 14%, OR: 0.6, p=0.1). Fibrinogen concentrates administration was associated with an increased risk of VTE (17% versus 9%, OR 2.2, p=0.02) whereas transfusion of fresh-frozen plasma had no effect. Heparin prophylaxis was associated with an increased risk of VTE (13% versus 7%, OR 1.9, p=0.04). Prophylactic measures were not associated with an increased risk of grade 3-4 bleeding complications. The rate of VTE recurrence after L-ASP reintroduction was 3% (1/34). In ALL patients receiving L-ASP therapy, the use of fibrinogen concentrates may increase the risk of thrombosis and should be restricted to rare patients with hypofibrinogenemia-induced hemorrhage. Patients developed VTE despite extensive AT supplementation which advocates for additional prophylactic measures. While this large descriptive study was not powered to demonstrate the efficacy of these prophylactic measures, it provides important insight to guide future trial design. NCT00327678.

Description: Chronic myelomonocytic leukemia ( CMML) is a de novo myelodysplastic/myeloproliferative disease with an unfavorable prognosis. Secondary CMML cases are rare and sporadically reported. Published data have shown that development of monocytosis in patients during the course of PMF or MDS is associated with poor prognosis (M.A. Elliott, Leukemia Research, 31 (2007). Essential thrombocythemia (ET) is an indolent myeloproliferative disorder characterized by long symptom-free intervals. Uncommonly, few patients with ET may develop bone marrow (BM) fibrosis which to be distinguished from cases with early PMF accompanied by thrombocytosis. Progression to acute leukemia or myelodysplastic syndrome (MDS) occurs in 〈 5% of patients and is likely related to previous cytotoxic therapy. We report here a rare case of a patient with ET who developed BM fibrosis and rapidly progressed to a secondary myelomonocytic leukemia. A 54 years old  female patient, diagnosed with ET in 2003,  as she presented a persistent isolated high platelet count of 700 G/L, with normal white blood cells (WBCs): 8 G/L, hemoglobin (hb): 15 g/dl,  monocytes: 0.5 G/L and no splenomegaly.  She was treated with Anagrelide 1.5 -2 mg daily due to intolerance to hydroxyurea. No major event has been declared during the last 10 years and a median platelet count of 450 G/L. In January 2013, a routine check-up showed leukocytosis (WBCs: 25 G/L), slight anemia (hb: 11.6 g/dl), with relative thrombocytopenia, 266 G/L, monocytosis:  2 G/L with 3% circulating blasts and a palpable spleen.  The bone marrow biopsy revealed BM fibrosis grade III and 7% of blasts.  Progression to secondary myelofibrosis was declared and treatment with hydroxyurea was initiated to control peripheral blood counts prior to transplantation.  Treatment with ruxolitinib started in May, at a dose of 20 mg bid due to failure of blood count reduction with hydroyurea. A rapid decline in WBCs count to 3 G/L was achieved but with sustained median monocytosis of 1.4 G/L.  The patient developed marked anemia (7.5 g/dl) as well as thrombocytopenia (13 G/L) and ruxolitinib was interrupted by the end of June 2013. Within 15 days, the patient showed rapid progression, her WBCs count attained 105 G/L, anemia and thrombocytopenia persisted. The absolute monocyte count increased up to 66 G/L with marked dysplastic features and morphological shifting to aspects compatible with overt secondary myelomonocytic leukemia in both blood and bone marrow smears, 3% circulating and 8% bone marrow blastes  (WHO criteria for CMML diagnosis). Molecular studies showed the presence of JAK2 V617F allele burden at 66% and absence of BCR/ABL transcript. Only two mitosis, with an unidentified additional marker were obtained on chromosome analysis. Unfortunately, the patient died 2 weeks later. This observation shows the adverse prognostic development of monocytosis in ET which is similar to that published in PMF in 10 patients (Leonardo Boiocchi, Modern pathology, 2013), thus requiring particular attention in the treatment of these patients. As chromosomal analysis was unavailable at diagnosis, we weren’t able to prove the presence of clonal heterogeneity, a concept developed recently to explain the mechanism of development of two different diseases. Ruxolitinib is an inhibitor of JAK1 and JAK2 resulting in a dramatic decrease in cytokines and growth factors that are important for hematopoiesis and growth function.  Of note, in this case, ruxolitinib which was administrated for the treatment of 2ry myelofibrosis, inhibited as well the increase in monocytosis and controlled the progression of CMML evidenced by the remarkable increase in dysplastic monocytes after its interruption. To our knowledge a clinical trial is actually on going to assess if its administration can improve the outcome of patients with CMML and the optimal dose to be administrated. Disclosures: No relevant conflicts of interest to declare.

Description: Purpose: Hyper-CVAD developed by the MD Anderson group a few years ago, is one of the standard salvage regimen used for younger relapsed/refractory ALL patients. Recently, targeted therapies using monoclonal antibodies directed against such surface antigens as CD19, CD20 or CD22 have allowed to obtain complete remission (CR) in B ALL expressing these markers. We hypothesized that combining Hyper-CVAD and an anti-CD22 monoclonal antibody could improve the response of such patients. Materials and Methods: This study evaluated the Cheprall salvage regimen, where epratuzumab, a humanized therapeutic monoclonal antibody against CD22 with mainly ADCC property, was associated to Hyper-CVAD, in younger patients (18-59 years old) with relapsed/refractory CD22+ (〉30% of expression) B-ALL. Cheprall consisted of epratuzumab 360 mg/m²/d iv on days 1, 8, 15 and 22, cyclophosphamide 300 mg/m²/12h iv on days 1 to 3, vincristine 2 mg iv on days +4 and +11, doxorubicin 50 mg/m² iv on day +4 and dexamethasone 40 mg po on days 1 to 4 and 11 to 14. The main objective of the study was the overall response rate (CR + CR with incomplete platelets recovery (=50% of bone marrow (BM) blasts decrease or CR with persistent extramedulladory disease) evaluated between 4 and 6 weeks from day+1. Secondary objectives were overall (OS) and leukemia free (LFS) survivals and minimal residual disease (MRD) evaluated by flow cytometry. Results: Between January 2011 and April 2016, 31 patients from 11 French centres were enrolled in the study. A combination of epratuzumab + vincristine and dexamethasone (EVD) only was given to one patient subsequently excluded from the analysis. Among the 30 patients ultimately considered for analyses, 19 were males and the median age was 35 years (range: 21-59). The median time between diagnosis and Cheprall was 14.5 months (range: 4-130) and 13 patients had been allotransplanted. Disease status at time of Cheprall was as follows: primary refractory n=3; first relapse non treated n=13; refractory first relapse n=6, second relapse non treated n=7 and fourth relapse n=1. Median percentage of white blood cells and BM blasts were 4525/mm3(range: 90-86790) and 60% (range: 15-100), respectively. The median CD22 expression of BM blasts was 100% (range: 36-100). Four patients had extramedullary disease: breast n=2, parotid n=1, nervous central system n=1 (deviation). Cheprall was overall well tolerated including mostly pancytopenia as grade ¾ toxicities. Three patients died during aplasia (septis n=1; cerebral haemorrhage n=1, fusariosis n=1) and were not evaluable for response. The overall response rate was 50% (n=15) including 9 CR (30%), 1 CRp (3%) and 5 PR (17%). The number of CR/CRp was higher for patients in first non-treated relapse (54% vs 18%) with an age below 36 years (50% vs 14%), with 18 months (54% vs 17%). Four out of 9 evaluated CR/CRp patients (45%) were documented with negative MRD. All patients in CR/CRp and 1 patient in PR received a consolidation consisting of a second cycle of Cheprall n=5, EVD n=5 or blinatumomab n=1. At the time of analysis (July 2016), all patients have died (during aplasia n=3, progression n=23, multiple organ failure n=1), except three responders still in CR, but yet recently enrolled (2015 n=1, 2016 n=2). Six patients received allogeneic transplant after Cheprall: 4 in CR2, 1 as salvage treatment and 1 in CR3. The last patient included and who achieved CR2 should be allografted in August 2016. Median OS was 3 months (range: 0.2-34.8). Median LFS for those achieving CR/CRp was 4.5 months (range: 1-12). Conclusion: Hyper-CVAD + epratuzumab allowed to obtain 50% of response in this cohort of patients at high risk of failure with refractory/relapsed younger CD22+ B-ALL. Disease improvement was however short-lived, which could be explained either by an insufficient disease load decrease and/or by escape of the blast cells to epratuzumab. This partial efficacy in a population of poor prognosis may suggest that epratuzumab should be tested within first-line chemotherapies as it may participate to decrease MRD level, especially before transplantation. The trial was registered at http://clinicaltrials.gov/ct no.NCT01219816. This study was supported by a grant from the French National Cancer Institute (PHRC 2010). Disclosures Huguet: Pfizer, Novartis, BMS, Ariad, Jazz, Amgen: Membership on an entity's Board of Directors or advisory committees. Thomas:Pfizer: Consultancy. Goldenberg:Immunomedics: Employment, Equity Ownership, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Wegener:Immunomedics: Employment, Honoraria.

Description: Background: Patients undergoing treatment for acute lymphoblastic leukemia (ALL) are at risk for thrombosis, in part due to the use of L-asparaginase (L-ASP) and subsequent antithrombine (AT) deficiency. Previous reports showed that patients with venous thrombotic events (VTE) have a lower event-free survival that may be due to early discontinuation of L-ASP. It has been suggested that AT replacement could decrease the rate of thrombosis and prevent L-ASP discontinuation. We report herein the results of the prophylactic replacement strategy in the pediatric-inspired prospective GRAALL-2005 study. Methods: All patients received a 5-drug induction therapy with 8 native E. Coli-ASP intravenous injections (6,000 UI/m2/injection). Patients in complete remission (CR) received two consolidation courses each containing two L-ASP intravenous injections (10000 UI/m2/injection). All patients in persistent CR for whom allogeneic stem cell transplantation was not indicated in first CR received a late intensification with the same drugs as in the induction course, followed by the repetition of one consolidation course. Platelet transfusion support was recommended for platelets below 20 x 109/L, fresh frozen plasma (FFP) or fibrinogen concentrates were recommended if fibrinogen levels fell below 0.5 g/L, and AT concentrate substitution therapy was recommended in order to maintain AT levels above 60%. Prophylactic heparin was recommended during induction and late intensification. All cases of VTE were identified prospectively by clinical signs and confirmed by radiological imaging based on institutional guidelines. Results: Between 2006 and 2014, 787 adult patients with newly diagnosed Philadelphia-negative ALL were included. The incidence rate of VTE was 14.4% (113 VTEs in 110 patients). VTEs included 72 (64%) deep vein thromboses (DVT), with one third in the lower limb and two thirds in the upper limb, 32 (28%) cerebral venous thrombosis (CVT), and 13 (12%) pulmonary embolism (PE). No disease characteristic was associated with a higher risk of thrombosis. Patients with DVT and/or PE were older (median age of 40 versus 38 for those with CVT versus 35 for those without VTE, p=0.04), had a higher BMI (median BMI of 26 versus 23 for those with CVT and 24 for those without VTE, p=0.01), and had a higher platelet count at diagnosis (median platelet count of 100 G/l versus 84 G/l for those with CVT versus 68 G/l for those without VTE, p=0.06) whereas patients with CVT had higher hemoglobin levels (median hemoglobin level of 11.7 g/dl versus 10.1 g/dl for those with DVT/PE versus 10.2 g/dl for those without VTE, p=0.03). Sixty-seven percent of VTEs occurred during induction therapy. Other VTEs occurred as follows: 17 (15%) during consolidation phase 1 (688 patients), 4 (4%) during consolidation phase 2 (537 patients), 9 (8%) during late intensification (356 patients), and 7 (6%) in 335 during consolidation phase 3 (335 patients). The type of thrombosis was different according to treatment phase as most CVT occurred during induction therapy (29 versus 3 CVTs during subsequent phases of treatment, p=0.003). During induction therapy, patients with VTE were more likely to have received heparin prophylaxis (82% versus 60% for those without VTE, odds ratio (OR) 1.8, p=0.06) and fibrinogen prophylaxis (14% versus 8% for those without VTE, OR 2, p=0.05) whereas they received less AT prophylaxis (82% versus 88% for those without VTE, OR 0.5, p=0.05). Patients with VTE received less L-ASP infusions during induction therapy (median number of 7 versus 8 injections for those without VTE, p