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The independent prognostic impact of specific dysplastic features in acute myeloid leukemia (AML) remains controversial and may vary between genomic subtypes. We apply a machine learning framework to dissect the relative contribution of centrally reviewed dysplastic features and oncogenetics in 190 patients with de novo AML treated in ALFA clinical trials. One hundred and thirty-five (71%) patients achieved complete response after the first induction course (CR). Dysgranulopoiesis, dyserythropoiesis and dysmegakaryopoiesis were assessable in 84%, 83% and 63% patients, respectively. Multi-lineage dysplasia was present in 27% of assessable patients. Micromegakaryocytes (q = 0.01), hypolobulated megakaryocytes (q = 0.08) and hyposegmented granulocytes (q = 0.08) were associated with higher ELN-2017 risk. Using a supervised learning algorithm, the relative importance of morphological variables (34%) for the prediction of CR was higher than demographic (5%), clinical (2%), cytogenetic (25%), molecular (29%), and treatment (5%) variables. Though dysplasias had limited predictive impact on survival, a multivariate logistic regression identified the presence of hypolobulated megakaryocytes (p = 0.014) and micromegakaryocytes (p = 0.035) as predicting lower CR rates, independently of monosomy 7 (p = 0.013), TP53 (p = 0.004), and NPM1 mutations (p = 0.025). Assessment of these specific dysmegakarypoiesis traits, for which we identify a transcriptomic signature, may thus guide treatment allocation in AML.

Despite a moderate prevalence in low-risk myelodysplastic syndromes (MDS) and chronic myelomonocytic leukaemia (CMML), thrombocytopenia remains a risk of severe bleeding and therapeutic options are still limited. There are only a few studies with eltrombopag (ELT), a thrombopoietin receptor agonist, in those patients. In this retrospective multicentre study, ELT was used in 50 patients with MDS and 11 with CMML, with no excess of marrow blasts and platelet counts of

PURPOSE TP53-mutated ( TP53m) myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) have very poor outcome irrespective of the treatment received, including 40% responses (20% complete remission [CR]) with azacitidine (AZA) alone, short response duration, and a median overall survival (OS) of approximately 6 months. Eprenetapopt (APR-246), a novel first-in-class drug, leads to p53 protein reconformation and reactivates its proapoptotic and cell-cycle arrest functions. PATIENTS AND METHODS This phase II study assessed the safety and efficacy of eprenetapopt in combination with AZA in untreated high or very high International Prognostic Scoring System-R TP53m MDS and AML patients. RESULTS Fifty-two TP53m patients (34 MDS, 18 AML [including seven with more than 30% blasts]) were enrolled. In MDS, we observed an overall response rate (ORR) of 62%, including 47% CR, with a median duration of response at 10.4 months. In AML, the ORR was 33% including 17% CR (27% and 0% CR in AML with less than and more than 30% marrow blasts, respectively). Seventy-three percent of responders achieved TP53 next-generation sequencing negativity (ie, variant allele frequency < 5%). The main treatment-related adverse events were febrile neutropenia (36%) and neurologic adverse events (40%), the latter correlating with a lower glomerular filtration rate at treatment onset ( P < .01) and higher age ( P = .05), and resolving with temporary drug interruption without recurrence after adequate eprenetapopt dose reduction. With a median follow-up of 9.7 months, median OS was 12.1 months in MDS, and 13.9 and 3.0 months in AML with less than and more than 30% marrow blasts, respectively. CONCLUSION In this very high-risk population of TP53m MDS and AML patients, eprenetapopt combined with AZA was safe and showed potentially higher ORR and CR rate, and longer OS than reported with AZA alone.

PURPOSE Approximately 20% of patients with TP53-mutant myelodysplastic syndromes (MDS) achieve complete remission (CR) with hypomethylating agents. Eprenetapopt (APR-246) is a novel, first-in-class, small molecule that restores wild-type p53 functions in TP53-mutant cells. METHODS This was a phase Ib/II study to determine the safety, recommended phase II dose, and efficacy of eprenetapopt administered in combination with azacitidine in patients with TP53-mutant MDS or acute myeloid leukemia (AML) with 20%-30% marrow blasts (ClinicalTrials.gov identifier: NCT03072043 ). RESULTS Fifty-five patients (40 MDS, 11 AML, and four MDS/myeloproliferative neoplasms) with at least one TP53 mutation were treated. The overall response rate was 71% with 44% achieving CR. Of patients with MDS, 73% (n = 29) responded with 50% (n = 20) achieving CR and 58% (23/40) a cytogenetic response. The overall response rate and CR rate for patients with AML was 64% (n = 7) and 36% (n = 4), respectively. Patients with only TP53 mutations by next-generation sequencing had higher rates of CR (69% v 25%; P = .006). Responding patients had significant reductions in TP53 variant allele frequency and p53 expression by immunohistochemistry, with 21 (38%) achieving complete molecular remission (variant allele frequency < 5%). Median overall survival was 10.8 months with significant improvement in responding versus nonresponding patients by landmark analysis (14.6 v 7.5 months; P = .0005). Overall, 19/55 (35%) patients underwent allogeneic hematopoietic stem-cell transplant, with a median overall survival of 14.7 months. Adverse events were similar to those reported for azacitidine or eprenetapopt monotherapy, with the most common grade ≥ 3 adverse events being febrile neutropenia (33%), leukopenia (29%), and neutropenia (29%). CONCLUSION Combination treatment with eprenetapopt and azacitidine is well-tolerated yielding high rates of clinical response and molecular remissions in patients with TP53-mutant MDS and oligoblastic AML.

Acute myeloid leukemia (AML) is a hematological malignancy with an undefined heritable risk. Here we perform a meta-analysis of three genome-wide association studies, with replication in a fourth study, incorporating a total of 4018 AML cases and 10488 controls. We identify a genome-wide significant risk locus for AML at 11q13.2 (rs4930561; P = 2.15 × 10−8; KMT5B). We also identify a genome-wide significant risk locus for the cytogenetically normal AML sub-group (N = 1287) at 6p21.32 (rs3916765; P = 1.51 × 10−10; HLA). Our results inform on AML etiology and identify putative functional genes operating in histone methylation (KMT5B) and immune function (HLA)., Genome wide association studies in cancer are used to understand the heritable genetic contribution to disease risk. Here, the authors perform a genome wide association study in European patients with acute myeloid leukemia and identify loci associated with risk of developing the disease.

Targeting TP53 mutated myelodysplastic syndromes and acute myeloid leukemia remains a significant unmet need. Recently, new drugs have attempted to improve the outcomes of this poor molecular subgroup. The aim of this article is to review all the current knowledge using active agents including hypomethylating agents with venetoclax, eprenetapopt or magrolimab. We include comprehensive analysis of clinical trials to date evaluating these drugs in TP53 myeloid neoplasms as well as discuss future novel combinations for consideration. Additionally, further understanding of the unique clinicopathologic components of TP53 mutant myeloid neoplasms versus wild-type is critical to guide future study. Importantly, the clinical trajectory of patients is uniquely tied with the clonal burden of TP53, which enables serial TP53 variant allele frequency analysis to be a critical early biomarker in investigational studies. Together, significant optimism is now possible for improving outcomes in this patient population.

The use of antihuman T-lymphocyte immunoglobulin in the setting of transplantation from an HLA-matched related donor is still much debated. Acute and chronic graft-versus-host disease are the main causes of morbidity and mortality after allogeneic hematopoietic stem cell transplantation in patients with myelofibrosis. The aim of this study was to evaluate the effect of antihuman T-lymphocyte immunoglobulin in a large cohort of patients with myelofibrosis (n=287). The cumulative incidences of grade II-IV acute graft-versus-host disease among patients who were or were not given antihuman T-lymphocyte immunoglobulin were 26% and 41%, respectively. The corresponding incidences of chronic graft-versus-host disease were 52% and 55%, respectively. Non-adjusted overall survival, disease-free survival and non-relapse mortality rates were 55% versus 53%, 49% versus 45%, and 32% versus 31%, respectively, among the patients who were or were not given antihuman T-lymphocyte immunoglobulin. An adjusted model confirmed that the risk of acute graft-versus-host disease was lower following antihuman T-lymphocyte immunoglobulin (hazard ratio, 0.54; P=0.010) while it did not decrease the risk of chronic graft-versus-host disease. The hazard ratios for overall survival and non-relapse mortality were 0.66 and 0.64, with P-values of 0.05 and 0.09, respectively. Antihuman T-lymphocyte immunoglobulin did not influence disease-free survival, graft-versus-host disease, relapse-free survival or relapse risk. In conclusion, in the setting of matched related transplantation in myelofibrosis patients, this study demonstrates that antihuman T-lymphocyte immunoglobulin decreases the risk of acute graft-versus-host disease without increasing the risk of relapse. ispartof: HAEMATOLOGICA vol:104 issue:6 pages:1230-1236 ispartof: location:Italy status: published

The value of pretransplant splenectomy in patients with myelofibrosis (MF) is subject to debate, since the procedure may preclude subsequent allogeneic hematopoietic cell transplantation (allo-HCT). To determine the impact of pretransplant splenectomy on the incidence of allo-HCT, we conducted a comprehensive retrospective study of all patients with MF for whom an unrelated donor search had been initiated via the French bone marrow transplantation registry (RFGM) between 1 January 2008 and 1 January 2017. Additional data were collected from the patients' medical files and a database held by the French-Language Society for Bone Marrow Transplantation and Cell Therapy (SFGM-TC). We used a multistate model with four states ("RFGM registration"; "splenectomy"; "death before allo-HCT", and "allo-HCT") to evaluate the association between splenectomy and the incidence of allo-HCT. The study included 530 patients from 57 centers. With a median follow-up time of 6 years, we observed 81 splenectomies, 99 deaths before allo-HCT (90 without splenectomy and nine after), and 333 allo-HCTs (268 without splenectomy and 65 after). In a bivariable analysis, the hazard ratio [95% confidence interval (CI)] for the association of splenectomy with allo-HCT was 7.2 [5.1-10.3] in the first 4 months and 1.18 [0.69-2.03] thereafter. The hazard ratio [95% CI] for death associated with splenectomy was 1.58 [0.79-3.14]. These reassuring results suggest that splenectomy does not preclude allo-HCT in patients with MF.

In order to identify cytomegalovirus (CMV)-seropositive patients who are at risk of developing CMV infection following first allogeneic hematopoietic cell transplantation (allo-HCT), we built up a scoring system based on patient/donor characteristics and transplantation modalities. To this end, 3690 consecutive patients were chronologically divided into a derivation cohort (2010-2012, n = 2180) and a validation cohort (2013-2014, n = 1490). Haploidentical donors were excluded. The incidence of first clinically significant CMV infection (CMV disease or CMV viremia leading to preemptive treatment) at 1, 3, and 6 months in the derivation cohort was 13.8%, 38.5%, and 39.6%, respectively. CMV-seropositive donor, unrelated donor (HLA matched 10/10 or HLA mismatched 9/10), myeloablative conditioning, total body irradiation, antithymocyte globulin, and mycophenolate mofetil significantly and independently affected the incidence of 3-month infection. These six factors were selected to build up the prognostic model. Four risk groups were defined: low, intermediate-low, intermediate-high, and high-risk categories, with a 3-month predicted incidence of first clinically significant CMV infection in the derivation cohort of 22.2%, 31.1%, 45.4%, and 56.9%, respectively. This score represents a framework for the evaluation of patients who are at risk of developing clinically significant CMV infection following allo-HCT. Prospective studies using this score may be of benefit in assessing the value of anti-CMV prophylaxis in well-defined patient cohorts.

Background: Patients with anemia and lower-risk myelodysplastic syndromes in whom erythropoiesis-stimulating agent therapy is not effective generally become dependent on red-cell transfusions. Luspatercept, a recombinant fusion protein that binds transforming growth factor β superfamily ligands to reduce SMAD2 and SMAD3 signaling, showed promising results in a phase 2 study. Methods: In a double-blind, placebo-controlled, phase 3 trial, we randomly assigned patients with very-low-risk, low-risk, or intermediate-risk myelodysplastic syndromes (defined according to the Revised International Prognostic Scoring System) with ring sideroblasts who had been receiving regular red-cell transfusions to receive either luspatercept (at a dose of 1.0 up to 1.75 mg per kilogram of body weight) or placebo, administered subcutaneously every 3 weeks. The primary end point was transfusion independence for 8 weeks or longer during weeks 1 through 24, and the key secondary end point was transfusion independence for 12 weeks or longer, assessed during both weeks 1 through 24 and weeks 1 through 48. Results: Of the 229 patients enrolled, 153 were randomly assigned to receive luspatercept and 76 to receive placebo; the baseline characteristics of the patients were balanced. Transfusion independence for 8 weeks or longer was observed in 38% of the patients in the luspatercept group, as compared with 13% of those in the placebo group (P Conclusions: Luspatercept reduced the severity of anemia in patients with lower-risk myelodysplastic syndromes with ring sideroblasts who had been receiving regular red-cell transfusions and who had disease that was refractory to or unlikely to respond to erythropoiesis-stimulating agents or who had discontinued such agents owing to an adverse event. (Funded by Celgene and Acceleron Pharma; MEDALIST ClinicalTrials.gov number, NCT02631070. opens in new tab; EudraCT number, 2015-003454-41. opens in new tab.)

Acute myeloid leukemia (AML) is frequently associated with hyperleukocytosis [white blood cell count (WBC) of >50 or >100 × 109/L at presentation] [1]. Hyperleukocytosis also predicts a higher risk...

In this study, we aimed to refine prognostication of older with acute myeloid leukemia (AML) after intensive chemotherapy. Five hundred and nine patients aged 60 years or older (median age, 68 years) were prospectively enrolled in the intensive Acute Leukemia French Association (ALFA)-1200 trial between 2012 and 2016, and 471 patient samples were submitted to multigene analysis. Mutations in any of 8 genes frequently altered in myelodysplastic syndromes (MDS), including ASXL1, SRSF2, STAG2, BCOR, U2AF1, EZH2, SF3B1, and ZRSR2, defined a secondary AML (sAML)-like disease, as reported. Of the samples analyzed, 48% included sAML-like gene mutations. These mutations were associated with a shorter event-free survival, both overall (hazard ratio, 1.46; 95% confidence interval, 1.19-1.79; P < .001) and within the European LeukemiaNet (ELN)-2017 intermediate-risk subgroup (hazard ratio, 1.52; 95% confidence interval, 1.01-2.28; P = .044), which excludes ASXL1-mutated cases by definition. We therefore included patients with intermediate-risk AML carrying sAML-like mutations in a single high-risk patients group together with adverse-risk patients with AML, whereas other intermediate-risk patients were included in a standard-risk group together with favorable-risk patients (high-risk/standard-risk patient ratio, 1.00). Using this 2-class risk assessment, we observed that transplantation prolonged overall survival from remission in patients with high-risk AML only, not in patients with standard-risk AML. Routine analysis of sAML-like gene mutations may thus improve the definition of high-risk older patients with AML, and better identify the half of older patients who clearly derive survival benefit from allogeneic transplantation in first remission. This trial was registered at www.clinicaltrials.gov as #NCT01966497.

Hypomethylating agent (HMA) failure in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) carries a poor prognosis with limited treatment options. Although intensive, remission induction chemotherapy is often used subsequently, in particular to bridge to allogeneic transplantation, it is not clear whether an advantage exists for any particular regimen. Based on an international collaboration, we retrospectively analyzed induction response rate and survival in 366 patients after HMA failure. Patients received 7+3, intermediate- to high-dose cytarabine (IDAC), or purine nucleoside analog-based regimens. For the MDS cohort (n = 307), the overall response rate (ORR) was 41%; median overall survival (OS) was 10.8 months, and 40% of responding patients bridged to allogeneic stem cell transplant (allo-SCT). For the AML cohort (n = 59), the ORR was 32%, OS 6 months, and 42% of responding patients bridged to allo-SCT. Prognostic factors for response in MDS included adverse cytogenetics (odds ratio [OR], 0.46, P = .01), age ≥65 years (OR, 0.47; P < .01), and use of IDAC (OR, 2.91, P = .01). Shorter survival was associated with adverse cytogenetics (hazard ratio [HR], 1.43; P = .06). In the AML cohort, OS was decreased by disease progression at time of HMA failure (HR, 2.66; P = .02) and prolonged with use of an anthracycline-containing regimen (HR, 0.37; P = .01). In conclusion, intensive chemotherapy after HMA failure may be a reasonable treatment option for selected patients as a bridge to allogeneic transplantation and should be considered a potential platform for future investigations.

Myelodysplastic syndromes (MDS) are hematopoietic stem cell malignancies. Known predisposing factors to adult MDS include rare germline mutations, cytotoxic therapy, age-related clonal hematopoiesis, and autoimmune or chronic inflammatory disorders. To date, no published studies characterizing MDS-associated germline susceptibility polymorphisms exist. We performed a genome-wide association study of 2 sample sets (555 MDS cases vs 2964 control subjects; 352 MDS cases vs 2640 control subjects) in non-del(5q) MDS cases of European genomic ancestry. Meta-analysis identified 8 MDS-associated loci at 1q31.1 (PLA2G4A), 3p14.1 (FAM19A4), 5q21.3 (EFNA5), 6p21.33, 10q23.1 (GRID1), 12q24.32, 15q26.1, and 20q13.12 (EYA2) that approached genome-wide significance. Gene expression for 5 loci that mapped within or near genes was significantly upregulated in MDS bone marrow cells compared with those of control subjects (P < .01). Higher PLA2G4A expression and lower EYA2 expression were associated with poorer overall survival (P = .039 and P = .037, respectively). Higher PLA2G4A expression is associated with mutations in NRAS (P < .001), RUNX1 (P = .012), ASXL1 (P = .007), and EZH2 (P = .038), all of which are known to contribute to MDS development. EYA2 expression was an independently favorable risk factor irrespective of age, sex, and Revised International Scoring System score (relative risk, 0.67; P = .048). Notably, these genes have regulatory roles in innate immunity, a critical driver of MDS pathogenesis. EYA2 overexpression induced innate immune activation, whereas EYA2 inhibition restored colony-forming potential in primary MDS cells indicative of hematopoietic restoration and possible clinical relevance. In conclusion, among 8 suggestive MDS-associated loci, 5 map to genes upregulated in MDS with functional roles in innate immunity and potential biological relevance to MDS.

Introduction Therapy-related myelodysplastic syndrome and acute myeloid leukemia (t-MDS/AML) are defined as complications of previous cytotoxic therapy. Azacitidine (AZA), a hypomethylating agent, has showed activity in t-MDS/AML. Objectives We evaluated the clonal dynamics of AZA-treated t-MDS/AML. Methods We collected bone marrow samples, at diagnosis and during treatment, from AZA-treated t-MDS/AML patients. NGS on 19 myeloid genes was performed, and candidate mutations with a variant allele frequency >5% were selected. Results Seven t-AML and 12 t-MDS were included with median age of 71 (56-82) years old, median number of AZA cycles of 6 (1-15), and median overall survival (OS) of 14 (3-29) months. We observed correlation between AZA response and clonal selection. Decrease of TP53-mutated clone was correlated with response to AZA, confirming AZA efficacy in this subgroup. In some patients, emergence of mutations was correlated with progression or relapse without impact on OS. Clones with mutations in genes for DNA methylation regulation frequently occurred with other mutations and remained stable during AZA treatment, independent of AZA response. Conclusion We confirmed that the molecular complexity of t-MNs and that the follow-up of clonal selection during AZA treatment could be useful to define treatment combination.

Isolated trisomy 8 (+8) is a frequent cytogenetic abnormality in the myelodysplastic syndromes (MDS), but its characteristics are poorly reported. We performed a retrospective study of 138 MDS patients with isolated +8, classified or reclassified as MDS (excluding MDS/myeloproliferative neoplasm). Myeloproliferative (MP) features were defined by the repeated presence of one of the following: white blood cell count >10 × 109 /l, myelemia (presence of circulating immature granulocytes with a predominance of more mature forms) >2%, palpable splenomegaly. Fifty-four patients (39·1%) had MP features: 28 at diagnosis, 26 were acquired during evolution. MP forms had more EZH2 (33·3% vs. 12·0% in non-MP, P = 0·047), ASXL1 (66·7% vs. 42·3%, P = 0·048) and STAG2 mutations (77·8% vs. 21·7%, P = 0·006). Median event-free survival (EFS) and overall survival (OS) were 25 and 27 months for patients with MP features at diagnosis, versus 28 (P = 0·15) and 39 months (P = 0·085) for those without MP features, respectively. Among the 57 patients who received hypomethylating agent (HMA), OS was lower in MP cases (13 months vs. 23 months in non-MP cases, P = 0.02). In conclusion, MP features are frequent in MDS with isolated +8. MP forms had more EZH2, ASXL1 and STAG2 mutations, responded poorly to HMA, and tended to have poorer survival than non-MP forms.

Patients with primary refractory or relapsed-acute myeloid leukemia (RR-AML), particularly older adults, have dismal outcomes and limited therapy options [1]. Given the tolerability of hypomethylat...

Introduction: TP53 gene mutations (m TP53), found in up to 20% of MDS or AML pts and 30-40% of therapy-related (TR) MDS/AML cases, represent a distinct molecular cohort with poor outcomes. Hypomethylating agents (HMA) are the frontline standard of care, with CR rates of ~20% and median OS of < 12 months. APR-246 is a novel, first-in-class small molecule that reactivates the mutant p53 protein and targets cellular redox balance, ultimately inducing apoptosis and ferroptosis in m TP53 cancer cells. We previously reported the Phase 2 results of 2 parallel trials of APR-246+AZA (Sallman et al and Cluzeau et al., JCO 2021). We now report analyses of the combined Phase 2 cohorts and long-term follow-up. Methods: This is a multicenter, international collaboration of the US MDS clinical research consortium and the GFM of HMA-naïve m TP53 higher-risk MDS, MDS/MPN and oligoblastic AML (≤ 30% blasts) pts (NCT03072043/NCT03588078). Pts received APR-246 4500mg IV (days 1-4) + AZA 75 mg/m 2 SC/IV x 7 days (days 4-10 or 4-5 and 8-12) in 28-day cycles. Primary objective was CR rate by International Working Group (IWG) 2006 criteria. Secondary objectives included ORR, OS, outcome following allogeneic hematopoietic stem cell transplant (allo-HSCT), with serial high depth next generation sequencing (NGS, 0.1% cutoff) for evaluation of measurable residual disease (MRD). Results: As of July 15, 2021, 100 pts had been enrolled with a median age of 68 years (range, 34-87; 47% male). By WHO, 74 pts had MDS, 22 AML-MRC and 4 CMML/MDS-MPN; 83% complex karyotype (CK) and 88% were CK and/or biallelic for TP53 mutations; 92% had a TP53 missense mutation in the DNA binding domain. In 63 pts, TP53 was the only mutation detected (i.e. isolated m TP53). Median time on treatment was 6 cycles (1-25+) with 5 pts ongoing and 23 pts who proceeded to allo-HSCT. Non-hematologic treatment (Tx)-related adverse events (AEs) in ≥20% of pts included nausea/vomiting (58%), ataxia (26%), and dizziness (23%). Neurologic AEs were reversible in 100% of cases. Febrile neutropenia occurred in 37% of pts. Thirty and 60-day mortality was 1% (n=1) and 7% (n=7), respectively. Dose reductions of APR-246 and AZA occurred in 16% and 1% of pts, respectively, with only 1 treatment discontinuation due to a treatment-related AE. By intention-to-treat (ITT) analysis, ORR by IWG was 69% with 43 CR, 1 PR, 10 marrow CR (mCR)+HI, 9 HI alone, and 6 with mCR. Of non-responders, 6 had stable disease and 7 pts had progressive disease. The median duration of CR/PR was 10.6 months (95% CI 8.8-12.3, 23+ months ongoing). CR/PR rate for MDS was 49% (36/74), 36% for AML (8/22) and 0% for MDS/MPN (0/4) with an ORR rate of 70%/64%/75%, respectively. Isolated m TP53 was predictive for a higher CR rate (52% vs 30%; P=.04). Patients who had biallelic TP53 or CK had a significantly higher CR rate vs pts without (49% vs 8%; P=0.01). On serial TP53 NGS using a VAF cutoff of 5%, 40 pts achieved NGS negativity with 6 pts MRD negative (VAF < 0.1%). Of NGS negative pts (TP53 VAF At data-cutoff by ITT analysis with a median follow up of 27.8 months, median OS was 11.8 months (95% CI 9.4-14.3). Pts undergoing allo-HSCT had a median OS of 16.1 months (95% CI 14-18.1). Impact of response and NGS clearance was evaluated by landmark analysis at 6 months. Pts achieving CR/PR or NGS negativity had improved OS (15.8 vs 10.1 months; P=0.002; Fig 1A). Additionally, pts who became MRD negative had a 2-year OS of 50% vs 23% (P=0.21). Although allo-HSCT was not predictive of OS in the overall cohort by landmark analysis (14.7 vs 14.4 months; P=0.15; Fig 1B), significant OS improvement was noted in allo-HSCT pts based on CR/PR or NGS negativity (P=0.002; Fig 1C). Notably, pts who achieved CR/PR/NGS negativity and were bridged to allo-HSCT had a median OS that was not reached (95% CI 10.4-NR) vs 9.1 months (95% CI 7.4-NR) in allo-HSCT pts who did not achieve this response (P=0.01). Conclusions: In this international, combined analysis of P2 APR-246+AZA pts, the combination was well-tolerated with high response rates in m TP53 MDS/AML. Quality of response and NGS negativity strongly predicted OS, particularly in the setting of allo-HSCT, validating NGS clearance as a critical biomarker of allo-HSCT outcomes in m TP53 pts. Figure 1 Figure 1. Disclosures Sallman: Intellia: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite: Membership on an entity's Board of Directors or advisory committees; Aprea: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees; Magenta: Consultancy; Shattuck Labs: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Syndax: Membership on an entity's Board of Directors or advisory committees; Incyte: Speakers Bureau; Agios: Membership on an entity's Board of Directors or advisory committees. Komrokji: BMS: Honoraria, Speakers Bureau; JAZZ: Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau; Novartis: Honoraria; Geron: Honoraria; Acceleron: Honoraria; Agios: Honoraria, Speakers Bureau. DeZern: Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees. Sebert: BMS: Consultancy; Abbvie: Consultancy. Steensma: Novartis: Current Employment. Roboz: Astellas: Consultancy; Otsuka: Consultancy; Blueprint Medicines: Consultancy; AbbVie: Consultancy; Bayer: Consultancy; Glaxo SmithKline: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Helsinn: Consultancy; Janssen: Consultancy; Novartis: Consultancy; Jasper Therapeutics: Consultancy; MEI Pharma - IDMC Chair: Consultancy; Janssen: Research Funding; AstraZeneca: Consultancy; Jazz: Consultancy; Amgen: Consultancy; Daiichi Sankyo: Consultancy; Mesoblast: Consultancy; Agios: Consultancy; Pfizer: Consultancy; Astex: Consultancy; Actinium: Consultancy; Roche/Genentech: Consultancy. Sekeres: BMS: Membership on an entity's Board of Directors or advisory committees; Takeda/Millenium: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Sweet: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; AROG: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Bristol Meyers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees. Kuykendall: Incyte: Consultancy; Novartis: Honoraria, Speakers Bureau; Prelude: Research Funding; PharmaEssentia: Honoraria; CTI Biopharma: Honoraria; Celgene/BMS: Honoraria, Speakers Bureau; BluePrint Medicines: Honoraria, Speakers Bureau; Abbvie: Honoraria; Protagonist: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Recher: Agios: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria; Janssen: Honoraria; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MaatPharma: Research Funding; Macrogenics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Raffoux: ASTELLAS: Consultancy; ABBVIE: Consultancy; PFIZER: Consultancy; CELGENE/BMS: Consultancy. Padron: Incyte: Research Funding; BMS: Research Funding; Blueprint: Honoraria; Kura: Research Funding; Taiho: Honoraria; Stemline: Honoraria. Attar: Aprea Therapeutics: Current Employment, Current equity holder in publicly-traded company. Kantarjian: Amgen: Honoraria, Research Funding; KAHR Medical Ltd: Honoraria; BMS: Research Funding; AbbVie: Honoraria, Research Funding; Ascentage: Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Astellas Health: Honoraria; Jazz: Research Funding; Aptitude Health: Honoraria; Astra Zeneca: Honoraria; Ipsen Pharmaceuticals: Honoraria; NOVA Research: Honoraria; Precision Biosciences: Honoraria; Immunogen: Research Funding; Daiichi-Sankyo: Research Funding; Taiho Pharmaceutical Canada: Honoraria. List: Precision BioSciences: Current Employment, Current equity holder in publicly-traded company; Aileron Therapeutics: Consultancy; CTI Biosciences: Consultancy; Halia Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company. Ades: Celgene: Honoraria, Research Funding; Abbvie: Honoraria; Takeda: Honoraria; Novartis: Honoraria; JAZZ: Honoraria. Lancet: BerGenBio: Consultancy; Celgene/BMS: Consultancy; Millenium Pharma/Takeda: Consultancy; Jazz: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; ElevateBio Management: Consultancy; Agios: Consultancy; AbbVie: Consultancy. Fenaux: Janssen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; JAZZ: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene/BMS: Honoraria, Research Funding; Syros Pharmaceuticals: Honoraria.

Methods : This multicentric retrospective study aimed to evaluate the efficacy and the safety of the combination of BBV in patients with non-cutaneous R/R PTCL among 21 LYSA centers in France and Belgium. The primary objective was to evaluate the best overall response rate (ORR) (complete response (CR) and partial response (PR)). Secondary objectives were progression free survival (PFS), overall survival (OS), duration of response (DoR), impact of transplantation on outcome, and safety. Patients treated between January 2013 and October 2020 were reviewed and all the data were collected through an electronic questionnaire sent to all the physicians. Results : Eighty two patients with R/R PTCL (40 angioimmunoblastic lymphoma (AITL), 2 T-cell lymphoma with TFH phenotype ,13 PTCL not otherwise specified (PTCL NOS), 5 Alk+ anaplastic large cell lymphoma (ALCL), 17 Alk- ALCL, , 1 Extranodal NK-/T-cell lymphoma, 3 Enteropathy-associated T-cell lymphoma (EATL), 1 subcutaneous panniculitis) were included. Median age at beginning of BBV was 60 years, most of patients were male (61%), had advanced stage (88%) and an IPI ≥ 2 (79%). Half of patients were refractory to their last treatment. Median number of prior regimens was 1 (range 1 to 6). The best ORR was 71%, with 51% of patients in CR. In multivariable analysis, only the relapse status after the last regimen (relapse vs refractory) was associated with ORR, relapsed patients having a better ORR (83% vs 57% in refractory patients, p=.014, OR=3.70 (95%CI:1.3-10.5)). Median DoR was 15.4 months in patients with CR but differed significantly whether patients were transplanted or not (Not reached vs 8.4 months, p=.0055). Twenty-two patients (30% of patients ≤ 70 years of age) were transplanted (6 autologous and 16 allogenic). With a median follow-up of 9 months, the median PFS and OS were 8.3 and 26.3 months respectively. In multivariable analysis, only 2 factors had a significant impact on PFS and OS: best response (CR/PR vs SD/PD with a median PFS of 17.4 vs 1.9 months, p Fifty-nine percent of patients experienced a grade 3 to 4 adverse event which was mainly hematologic toxicity. Treatment had to be stopped in 11% of patients. Conclusion: To the best of our knowledge, this is the first study reporting on the combination of BBV in the treatment of R/R PTCL in such a large cohort. The results are very encouraging with a high response rate, long DoR in responding patients and a very good outcome. Furthermore, patients in CR who are eligible for transplant have the best outcome, making this combination a good candidate as salvage therapy before transplant consolidation in these high-risk lymphomas with limited treatment options. Figure 1 Figure 1. Disclosures Bouabdallah: Kite/Gilead: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Roche: Consultancy, Honoraria. Herbaux: Takeda: Honoraria, Research Funding; Janssen: Honoraria; Roche: Honoraria; Abbvie: Honoraria, Research Funding. Brice: MSD: Research Funding; Amgen: Other: Travel/accommodations/expenses; Roche: Other: Travel/accommodations/expenses; Takeda: Research Funding. Sibon: Abbvie: Consultancy; Janssen: Consultancy; Roche: Consultancy; iQone: Consultancy; Takeda: Consultancy. Laribi: AstraZeneca: Other: Personal Fees; AbbVie: Other: Personal Fees, Research Funding; IQONE: Other: Personal Fees; Astellas Phama, Inc.: Other: Personal Fees; BeiGene: Other: Personal Fees; Takeda: Other: Personal Fees, Research Funding; Novartis: Other: Personal Fees, Research Funding; Le Mans Hospital: Research Funding; Jansen: Research Funding. Damaj: roche: Consultancy, Honoraria; takeda: Consultancy, Honoraria. OffLabel Disclosure: Brentuximab Vedotin and Bendamustine

Karyotype according to the revised IPSS is a strong independent prognostic factor for overall survival (OS) in myelodysplastic syndromes (MDS), however established in untreated patients. The prognostic impact of cytogenetics and cytogenetic response (CyR) in MDS patients receiving azacitidine (AZA) remains uncertain. We examined the prognostic value of baseline cytogenetics and CyR for overall response rate (ORR) and OS in 702 AZA-treated higher risk MDS and low blast count acute myeloid leukemia (AML), including 493 (70%) with abnormal karyotype. None of the cytogenetic abnormalities had significant impact on ORR (43.9%) or complete response (15.35%), except 3q abnormalities and complex karyotypes, which were associated with a lower ORR. OS differed significantly across all R-IPSS cytogenetic subgroups (p

Accumulating evidence implicates innate immune activation in the pathobiology of myelodysplastic syndromes. A key myeloid-related inflammatory protein, S100A9, serves as a Toll-like receptor ligand regulating tumor necrosis factor-α and interleukin-1β production. The role of myelodysplastic syndrome-related inflammatory proteins in endogenous erythropoietin regulation and response to erythroid-stimulating agents or lenalidomide has not been investigated. The HepG2 hepatoma cell line was used to investigate in vitro erythropoietin elaboration. Serum samples collected from 311 patients with myelodysplastic syndrome were investigated (125 prior to treatment with erythroid-stimulating agents and 186 prior to lenalidomide therapy). Serum concentrations of S100A9, S100A8, tumor necrosis factor-α, interleukin-1β and erythropoietin were analyzed by enzyme-linked immunosorbent assay. Using erythropoietin-producing HepG2 cells, we show that S100A9, tumor necrosis factor-α and interleukin-1β suppress transcription and cellular elaboration of erythropoietin. Pre-incubation with lenalidomide significantly diminished suppression of erythropoietin production by S100A9 or tumor necrosis factor-α. Moreover, in peripheral blood mononuclear cells from patients with myelodysplastic syndromes, lenalidomide significantly reduced steady-state S100A9 generation (P=0.01) and lipopolysaccharide-induced tumor necrosis factor-α elaboration (P=0.002). Enzyme-linked immunosorbent assays of serum from 316 patients with non-del(5q) myelodysplastic syndromes demonstrated a significant inverse correlation between tumor necrosis factor-α and erythropoietin concentrations (P=0.006), and between S100A9 and erythropoietin (P=0.01). Moreover, baseline serum tumor necrosis factor-α concentration was significantly higher in responders to erythroid-stimulating agents (P=0.03), whereas lenalidomide responders had significantly lower tumor necrosis factor-α and higher S100A9 serum concentrations (P=0.03). These findings suggest that S100A9 and its nuclear factor-κB transcriptional target, tumor necrosis factor-α, directly suppress erythropoietin elaboration in myelodysplastic syndromes. These cytokines may serve as rational biomarkers of response to lenalidomide and erythroid-stimulating agent treatments. Therapeutic strategies that either neutralize or suppress S100A9 may improve erythropoiesis in patients with myelodysplastic syndromes.

*AK, PP shared first-, UP, HM, LA shared senior authors Introduction: Hypomethylating agents (HMAs) are the standard of care for patients with higher-risk myelodysplastic syndrome (HR-MDS) or acute myeloid leukemia (AML), not eligible for intensive chemotherapy or allogeneic stem cell transplantation. However, the majority of patients do not respond to these agents. Patients failing HMA therapy still have a dismal outcome with very limited treatment options available. Bemcentinib (BEM) is a selective small molecule inhibitor of AXL, a surface membrane protein kinase receptor mediating resistance to chemotherapeutic agents and decreased antitumor immune response. AXL is overexpressed on leukemic cells, especially in the stem cell compartment, and represents a potential novel target in patients with MDS and AML. Methods: The multicenter phase 2 BERGAMO trial evaluated the safety and efficacy of BEM in patients with HR-MDS or AML, refractory to or relapsing after at least six or four cycles of either azacitidine (AZA) or decitabine (DAC), respectively. Patients received an initial loading dose of 400mg BEM orally administered on d1-3 of cycle 1 and a maintenance dose of 200mg BEM on d4-28 of cycle 1 as well as on d1-28 in subsequent 28-day cycles. The primary endpoint was overall response rate (CR, CRi, PR or SD) assessed after 4 treatment cycles. All patients who achieved CR, CRi, PR or SD after 4 cycles of BEM were considered as responders and allowed to continue treatment for a total of up to 9 cycles. Non-responding patients stopped treatment after 4 cycles. Secondary endpoints of the trial included a translational project evaluating the role of biomarkers and response. Results: Between 2018 and 2020, 58 patients in 10 European centers were screened (MDS=27/AML=31) with a median age of 78 years (range, 62-86 years). 45 patients (MDS=21, AML=24) received at least one cycle of BEM and were eligible for safety and efficacy analysis after the first 4 months of treatment. Thirty six (80%) out of 45 patients were considered relapsed after a response to HMA, 8 (18%) had primary resistance and 1 patient (2%) had HMA intolerance. The median number of prior AZA or DAC cycles was 13. In addition, 18 patients (40%) (MDS=9/AML=9) were red blood cell transfusion-dependent. Treatment with BEM was generally well tolerated with only low rates of grade 3-4 hematologic toxicities (n=7). Forty-seven serious adverse events (SAE) occurred in 22 patients (MDS=9/AML=13), mostly due to infectious complications (n=12), hematological toxicity (n=4) or gastrointestinal disturbance (n=6). Until the first 4 months of BEM treatment, the median number of BEM treatment cycles received was 1.5 (range, 0.5-4). During study, 9 patients (20%) died due to infection (MDS=1/AML=3), deterioration of general condition (MDS=1/AML=2) and progressive disease (MDS=0/AML=2). BEM treatment is currently ongoing in four patients (MDS=3/AML=1). The primary endpoint was met in 9 of 45 patients (20.0%). Within the MDS cohort 33.3% achieved a response (n=7/21; CR=1, CRi= 3, SD=3), while 8.3% of patients (n=2/24) with AML achieved stable disease(SD). The 4 MDS patients achieving CR/CRi had a normal karyotype and a median baseline IPSS-R score of 4 (range 3-5). Among the MDS non-responders 4 patients had a complex karyotype, median IPSS-R score was 5 (range 3-5). Median baseline bone marrow blast count was 15% vs. 13% and median pretreatment hemoglobin-, platelet- and WBC levels were 9.2 g/dl (range 7.9-11.8 g/dl), 51 G/L(range 26-120 G/L) and 1.9x109/l (range 1.18-8.9 x109/l) vs. 9.6 g/dl (range 7.9-11.3 g/dl), 35 G/L (range 0-167 G/L) and 1.45x109/l (range 0.82-6.97 x109/l) comparing MDS responders (CR/CRi) vs MDS non-responders, respectively. Preliminary data evaluating soluble AXL (sAXL) in blood plasma at baseline showed that 66.6 % (n=2/3) of MDS patients achieving CR/CRi displayed sAXL levels below a defined threshold, while this was only seen in 20% (n=2/10) of MDS non-responders. Conclusion: These results of the prospective phase II BERGAMO trial confirm, that single agent BEM is generally safe and well tolerated in this patient population with an unmet medical need. Importantly, BEM showed clinical efficacy in a subgroup of MDS patients. These encouraging clinical results are being further explored by an in depth translational research program aiming to identify additional molecular and biological prognostic factors associated with response. Disclosures Kubasch: Celgene: Research Funding; Shire: Research Funding; Novartis: Research Funding. Cluzeau:Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Menarini: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees. Götze:Celgene: Research Funding. Teipel:janssen: Honoraria. Jentzsch:Novartis: Honoraria; JAZZ Pharmaceuticals: Honoraria. Giagounidis:Novartis: Membership on an entity's Board of Directors or advisory committees; AMGEN: Membership on an entity's Board of Directors or advisory committees. McPherson:BerGenBio ASA: Current Employment. van de Loosdrecht:novartis: Honoraria; celgene: Honoraria. Fenaux:Jazz: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding. Platzbecker:BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; Geron: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Honoraria, Research Funding. Medyouf:Bergenbio: Consultancy, Research Funding. Ades:Celgene/BMS: Research Funding; novartis: Research Funding; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; jazz: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding. OffLabel Disclosure: Bemcentinib is currently undergoing Phase II clinical trials for non-small-cell lung cancer (NSCLC), triple-negative breast cancer (TNBC), acute myeloid leukemia /myelodysplastic syndrome (AML/MDS), melanoma and metastatic pancreatic cancer. In 2019, FDA have granted fast track designation to bemcentinib for the treatment of elderly patients with acute myeloid leukemia (AML) whose disease has relapsed.

Background: MDS-RS are associated with a low risk of Acute Myeloid Leukemia (AML) progression and prolonged survival in most cases, but recurring anemia whose treatments, including Erythropoiesis Stimulating Agent (ESA), Lenalidomide, hypomethylating agents (HMAs), Luspatercept, and experimental drugs generally have transient effect and/or are not widely available. MDS-RS patients thus eventually have regular Red Blood Cells (RBC) transfusion dependency (TD) associated with mean low hemoglobin levels, and chronic anemia responsible for reduced quality of life, cardiovascular complications, and iron overload with organ dysfunction. We performed a retrospective observational study to describe transfusion characteristics and costs, along with clinical events, in a French population of RBC TD MDS-RS patients. Methods: Adult RBC-TD patients with MDS-RS from 12 hematology departments of the GFM were included. The number of RBC concentrates transfused was assessed over the last 6 months (during which no other treatment than transfusions was received), and patients categorized in low transfusion burden (LTB: 3 to 7 RBC/16 weeks) and high transfusion burden (HTB: ≥8 RBC concentrates /16 weeks). Data about iron chelation, full time hospitalization (differing from day care facility stays for programmed transfusions), causes of hospitalization, treatment of anemia before inclusion and transfusion costs was collected. Results: 100 patients MDS-RS were included, with a median time from diagnosis of 5 years (1 to 21 years). Median age was 78 years (57 to 99). Patients had received a median of 2 lines of treatment (including an ESA in 97% of them). 21% had LTB and 79% HTB. HTB patients had a longer disease duration, more frequent iron chelation (82% versus 50% in LTB patients, p=0.0052) and higher serum ferritin at inclusion (median 1958 µg/l versus 1176 µg/l, p=0.03). During the 6-month study period, 22% of the patients required full time hospitalization (in addition to day care facility for transfusions), including 25% of patients with HTB and 15% with LTB, and 43% during overall disease follow-up. Causes of full time hospitalization (figure) were symptomatic anemia (41%), general condition degradation (5%) or cardiac disease (8%), to both of which anemia potentially contributed, infection (23%), bleeding (8%), pulmonary (2%), 13% for other reasons. 15 HTB patients versus 1 LTB patient were hospitalized for symptomatic anemia. The 6-months average transfusion costs, including cost of the day care facility for RBC transfusion, transportation to and from the hospital, lab tests and iron chelation were $21459/patient, excluding costs of full-time hospitalization for complications. The average cost in HTB and LTB patients was $22829 and $7586/patient, respectively. Conclusion: Most MDS-RS patients currently become RBC-TD, often during several years, and most have high transfusion burden. The average cost of RBC transfusions and iron chelation was $21459/ 6 months. During this short observation time, 22% of the patients required full time hospitalization, due to complications of anemia in at least 50% of the cases, which also increased costs (comparison with rates of hospitalization in an age and sex matched general population will be presented). Poor quality of life associated with chronic anemia should also be taken into account in those RBC-TD patients. Widely available treatments, capable of avoiding RBC transfusion dependence and improving mean hemoglobin levels, are required in those MDS-RS patients. Disclosures Cony-Makhoul: BMS: Speakers Bureau; Incyte Biosciences: Speakers Bureau; BMS: Consultancy; Novartis: Consultancy; Pfizer: Consultancy. Thepot:astellas: Honoraria; novartis: Honoraria; sanofi: Honoraria; celgene: Honoraria. Cluzeau:Celgene: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Menarini: Consultancy; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Stamatoulas Bastard:Takeda: Consultancy; Pfizer: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Celgene: Honoraria. Fenaux:Jazz: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; BMS: Honoraria, Research Funding. Park:Pfizer: Other: Travel expenses; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: 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.

// Thomas Prebet 1 , Thomas Cluzeau 2,* , Sophie Park 3,4,* , Mikkael A. Sekeres 5 , Ulrich Germing 6 , Lionel Ades 4,7 , Uwe Platzbecker 8 , Katharina Gotze 9 , Norbert Vey 4,10 , Esther Oliva 11 , Mary M. Sugrue 12 , Cecile Bally 4 , Charikleia Kelaidi 4 , Najla Al Ali 2 , Pierre Fenaux 4,7 , Steven D. Gore 1,* and Rami Komrokji 2,* 1 Moffit Cancer Center, Tampa, Florida, USA 2 Cote d’Azur University, Nice Sophia Antipolis University, Centre Hospitalier Universitaire de Nice, Nice, France 3 U1065, Mediterranean Center of Molecular Medecine, Nice, France 4 Groupe Francophone des Myelodysplasies, Hopital Saint Louis, Paris, France 5 Leukemia Program, Cleveland Clinic, Cleveland, OH, USA 6 Department Hematology, Oncology and Clinical Immunology, Heinrich Heine University, Dusseldorf, Germany 7 Service Hematologie Senior, Hopital Saint Louis, Paris, France 8 Universitats Klinikum Carl Gustav Carus, Dresden, Germany 9 Klinikum Rechts der Isar, Technische Universitat Munchen, Munchen, Germany 10 Departement d’Hematologie, Institut Paoli-Calmettes, Marseille, France 11 Hematology Unit, Azienda Ospedaliera Bianchi Melacrino Morelli, Reggio Calabria, Italy 12 Celgene Corporation, Summit, NJ, USA * These authors have contributed equally to this work Correspondence to: Thomas Prebet , email: // Keywords : myelodysplasia, outcome, lenalidomide Received : April 18, 2017 Accepted : April 24, 2017 Published : June 14, 2017 Abstract While lenalidomide (LEN) is the standard of care for the lower-risk myelodysplastic syndromes (MDS) patients with deletion 5q, 35% will not respond to or do not tolerate the drug. Moreover, most of the patients will lose their response after a few years. Defining the outcome of patients with LEN failure and determining the impact of subsequent therapies is therefore important to develop alternative strategies. Based on an international collaboration, we were able to compile a total of 392 patient cases of lower-risk MDS patients with 5q deletion and to analyze their outcome after failure of lenalidomide. The median survival following LEN failure was 23 months. We observed a negative impact on survival of advanced age, higher bone marrow blast count at LEN initiation, progression after LEN failure, and unfavorable cytogenetics. Among the treatment strategies, we observed a relatively prolonged survival of patients treated subsequently with hypomethylating agents and only a limited impact on survival of allogeneic transplantation. In conclusion, our work stresses the relatively short survival of this group of patient and defines the expected baseline for the needed future investigations in this group of patients.

High-dose chemotherapy before autologous transplantation is a therapeutic option as consolidation in primary or relapsed lymphoma. Even if BEAM conditioning is generally used, alternative conditioning regimens have been published. The purpose of this study was to assess the outcome of 177 adult patients with lymphoma whose conditioning treatment included a BAM (busulfan, aracytine, and melphalan) regimen. With a median follow-up of 17.4 months, 2-year estimates of overall survival and progression-free survival for the entire group were 87% and 70.5%, respectively. Mucositis was the main reported complications and infectious episodes were described in 80.2% of patients. According to multivariate analysis, high performance status and age at diagnosis were adverse factors for survival and increased the risk of disease relapse and death. Despite its limitations, this retrospective study suggests that BAM combination is a valid conditioning regimen in lymphoma patients, with an acceptable rate of toxicity.

Introduction CPX-351 is a liposomal formulation of cytarabine and daunorubicin packaged at a 5:1 molar ratio. This drug has recently been approved by FDA and EMEA for patients with therapy-related acute myeloid leukemia (t-AML) or AML with myelodysplasia-related changes (MRC-AML). The primary objective of this study was to analyze the efficacy of CPX-351 in a real-life setting, evaluating the impact of mutations on response and minimal residual disease (MRD) in responding patients. Methods We retrospectively collected data from patients treated by CPX-351 in eleven centers in France. Clinical, biological and treatment information were available for all patients. NGS (19 genes or more) was performed in 67 patients (84%) at diagnosis. Overall response rate (ORR) was defined by complete remission (CR) and CR with incomplete haematological recovery (CRi). Among the patients in CR or CRi, 25 (56%) had MRD evaluation assessed by NGS or flow cytometry. Overall survival (OS) was calculated from the date of AML diagnosis to the date of death or last follow-up. All statistical analyses were performed using SPSS v.22 software (IBM SPSS Statistics). Results Between April 2018 and July 2019, 80 patients treated with CPX-351 were included in this study. Sex ratio M/F was 43/37 and median age was 66 years old (range 20-83). AML subtypes were MRC-AML (61%) including AML with prior myelodysplastic syndrome (MDS-AML) (33%), prior chronic myelomonocytic leukemia (CMML-AML) (7%), or t-AML (29%). Sixteen patients (20%) had received prior treatment by hypomethylating agents (HMA), at the time of MDS diagnosis, before AML evolution. According to ELN 2017 classification, genetic risk was favorable, intermediate and adverse in 1 (1%), 31 (38%) and 47 (58%), respectively. 36% and 28% patients had complex and monosomal karyotypes, respectively. Assessed by NGS the most frequent mutated gene were : RUNX1 (n=17, 25%), TP53 (n=15, 22%), ASXL1 (n=14, 21%), TET2 (n=13, 19%), DNMT3A (n=11, 16%), srsf2 (n=9, 13%), FLT3-ITD (n=8, 12%), CBL (n=7, 10%), WT1 (n=7, 10%), and EZH2 (n=7, 10%). According to a genetic ontogeny-based classifier (Lindsley et al., Blood 2015), 23 patients (34%), 29 (43%), 15 (22%) had de novo/pan-AML, secondary type mutations AML, and TP53 mutated AML, respectively. Only 4 patients discontinuing treatment due to prolonged haematological toxicity. Early death rate was 5% and 8.75% through day 30 and day 60, respectively. Median time to neutrophil recovery (>0,5 G/L) and platelet recovery (>20G/L) after induction was 29 days (range 19-78) and 28 days (range 12-77), respectively. Seventy-five patients (95%) had at least one grade 3 or more AEs, including 69 (86%) febrile neutropenia. We observed gastrointestinal toxicity 32 patients (40%) (nausea/vomiting (30%/11%), mucositis (15%)) including 4% with grade 3 or more and alopecia in only 12%. ORR was 45/80 (56%) after induction 1 including 53% CR and 3% CRi. ORR increased to 58% after induction 2. Among the 45 CR/CRi patients, 25 were evaluable for MRD at the time of the 1st consolidation. 72% had MRD below 10-3 (64% below 10-4). Prior treatment by HMA and presence of monosomal karyotype were identified as factors predicting a lower rate of CR/CRi (P=0.001 and P=0.002, respectively). Lindsley's classifier predicted significantly a better chemosensitivity in de novo/pan-AML mutations (P= 0.037). Poor molecular prognosis subgroups defined by 2017 ELN risk stratification (n = 53) as TP53, ASXL1, RUNX1 and EVI1 mutations were not associated with a lower response rate with CPX-351 (Table 1). Twenty-one (26%) patients underwent an allogeneic haematopoietic stem cell transplant (HSCT) with an improved median OS compared to non-transplanted patients (non reached vs 8 months, P= 0.004). With a median follow up of 8.5 months, median OS was not reached. Survival analysis in subgroups will be available for the ASH meeting. Conclusion These data confirmed the efficacy and safety of CPX-351 in poor risk AML (t-AML and MRC-AML). The high rate of CR with low MRD compares favorably with previous report using 7+3 in elderly unfavorable AML (Sylvie D. Freeman et al., JCO 2013) and may explain the favorable outcome observed in patients after HSCT. Moreover, CPX-351 erases the poor prognosis associated with unfavorable mutations defined in 2017 ELN risk stratification. Lindsley's classifier was the best prognostic scoring system in patients treated by CPX-351. Disclosures Bertoli: Daiichi Sankyo: Consultancy; Astellas: Consultancy, Honoraria; Sanofi: Honoraria; Jazz Pharmaceuticals: Honoraria. Peterlin:Jazz Pharma: Consultancy; AbbVie Inc: Consultancy; Astellas: Consultancy; Daiichi-Sankyo: Consultancy. Chevallier:Incyte: Consultancy, Honoraria; Daiichi Sankyo: Honoraria; Jazz Pharmaceuticals: Honoraria. Thomas:INCYTE: Honoraria; DAICHI: Honoraria; PFIZER: Honoraria; ABBVIE: Honoraria. Mohty:Jazz Pharmaceuticals: Honoraria, Research Funding. Pigneux:Daichi: Honoraria; Abbvie: Honoraria; Jazz: Honoraria; Astellas: Honoraria; Roche: Honoraria; Pfizer: Honoraria; F. Hoffmann-La Roche Ltd: Honoraria; Amgen: Honoraria; Novartis: Honoraria. Recher:Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Macrogenics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sunesis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria; Astellas: 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. Ades:Amgen: Research Funding; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Silence Therapeutics: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees. Cluzeau:Abbvie: Consultancy; Jazz Pharma: Consultancy; Menarini: Consultancy.

International audience; Myelodysplastic syndromes (MDS) with ring sideroblasts are hematopoietic stem cell disorders with erythroid dysplasia and mutations in the SF3B1 splicing factor gene. Patients with MDS with SF3B1 mutations often accumulate excessive tissue iron, even in the absence of transfusions, but the mechanisms that are responsible for their parenchymal iron overload are unknown. Body iron content, tissue distribution, and the supply of iron for eryth-ropoiesis are controlled by the hormone hepcidin, which is regulated by erythroblasts through secretion of the erythroid hormone erythroferrone (ERFE). Here, we identified an alternative ERFE transcript in patients with MDS with the SF3B1 mutation. Induction of this ERFE transcript in primary SF3B1-mutated bone marrow erythroblasts generated a variant protein that maintained the capacity to suppress hepcidin transcription. Plasma concentrations of ERFE were higher in patients with MDS with an SF3B1 gene mutation than in patients with SF3B1 wild-type MDS. Thus, hepcidin suppression by a variant ERFE is likely responsible for the increased iron loading in patients with SF3B1-mutated MDS, suggesting that ERFE could be targeted to prevent iron-mediated toxicity. The expression of the variant ERFE transcript that was restricted to SF3B1-mutated erythroblasts decreased in lenalidomide-responsive anemic patients, identifying variant ERFE as a specific biomarker of clonal erythropoiesis.

Introduction: MDS is associated with an erythroid maturation defect, characterized by ineffective erythropoiesis leading to anemia and RBC transfusion dependence. Treatment of anemia in lower-risk MDS remains an unmet medical need. Luspatercept is a first-in-class erythroid maturation agent which binds to select TGFβ superfamily ligands to reduce aberrant Smad2/3 signaling and enhance late-stage erythropoiesis (Suragani RN, et al. Nat Med. 2014;20:408-14). Preliminary clinical studies have shown promising activity in MDS (Platzbecker U, et al. Lancet Oncol. 2017;10:1338-47). We report the results of a phase 3, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of luspatercept in patients with anemia due to Revised International Prognostic Scoring System (IPSS-R)-defined Very low-, Low-, or Intermediate-risk MDS with RS who require RBC transfusions. ClinicalTrials.gov identifier: NCT02631070. Methods: Eligible patients were aged ≥ 18 years; had IPSS-R-defined Very low-, Low-, or Intermediate-risk MDS with RS according to the WHO 2016 criteria; were refractory, intolerant, or ineligible to receive erythropoiesis-stimulating agents (ESAs); and required RBC transfusions. Patients were randomized 2:1 to receive either luspatercept, at a starting dose level of 1.0 mg/kg with titration up to 1.75 mg/kg, if needed, or placebo, subcutaneously every 3 weeks for ≥ 24 weeks. The primary endpoint was RBC transfusion independence (RBC-TI) for ≥ 8 weeks between week 1 and week 24. A key secondary endpoint was RBC-TI for ≥ 12 weeks between week 1 and 24. Achievement of modified hematologic improvement-erythroid (mHI-E) response using IWG 2006 criteria was also assessed. Results: † A total of 229 patients were randomized and treated. Median age was 71 years (range 26-95), median time from diagnosis was 41.8 months (range 3-421), and 62.9% were male. Overall, patient baseline characteristics were balanced between the treatment groups. Patients received a median of 5 RBC units (range 1-20) transfused over 8 weeks during the 16 weeks prior to treatment (43.2% of patients had ≥ 6 RBC units/8 weeks, 27.9% had ≥ 4 to < 6 RBC units/8 weeks, and 28.8% had < 4 RBC units/8 weeks). At baseline, 138 (60.3%), 58 (25.3%), and 32 (14.0%) patients had serum erythropoietin levels < 200 IU/L, 200-500 IU/L, and > 500 IU/L, respectively. A total of 218 (95.2%) patients had previously received ESAs. Overall, 206 (90.0%) patients had an SF3B1 mutation. Of 153 patients receiving luspatercept, 58 (37.9%) achieved the primary endpoint of RBC-TI for ≥ 8 weeks compared with 10 of 76 patients (13.2%) receiving placebo (odds ratio [OR] 5.1, P < 0.0001). Of those receiving luspatercept, 43 of 153 (28.1%) achieved the key secondary endpoint of RBC-TI for ≥ 12 weeks (weeks 1-24) compared with 6 of 76 (7.9%) receiving placebo (OR 5.1, P = 0.0002). Patients receiving luspatercept were more likely to achieve an mHI-E response, defined as a reduction in transfusion of ≥ 4 RBC units/8 weeks or a mean hemoglobin increase of ≥ 1.5 g/dL/8 weeks in the absence of transfusions, compared with patients receiving placebo (52.9% vs 11.8% during weeks 1-24; P < 0.0001). The safety profile of luspatercept was consistent with that reported in the phase 2 PACE-MDS study (Platzbecker U, et al. Lancet Oncol. 2017;10:1338-47). Conclusions: Treatment with luspatercept resulted in a significantly reduced transfusion burden compared with placebo in patients with anemia due to IPSS-R-defined Very low-, Low-, or Intermediate-risk MDS with RS, who require RBC transfusions, and was generally well tolerated. P.F. and U.P. contributed equally to this abstract as lead co-authors. R.S.K. and A.F.L. contributed equally to this abstract as senior co-authors. † As of May 8, 2018, cutoff date. Disclosures Fenaux: Otsuka: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Platzbecker:Celgene: Research Funding. Mufti:Celgene: Research Funding. Buckstein:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Santini:Otsuka: Consultancy; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Research Funding; Novartis: Honoraria; AbbVie: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Díez-Campelo:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Finelli:Novartis: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Celgene: Research Funding, Speakers Bureau. Ilhan:Alexion: Speakers Bureau; BMS: Speakers Bureau; Roche: Speakers Bureau; Celgene: Speakers Bureau. Sekeres:Opsona: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Falantes:Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Giai:Novartis: Consultancy; Pfizer: Consultancy. Selleslag:Kiadis Pharma: Other: Financial support for study-related issues. Jurcic:Actinium Pharmaceuticals, Inc: Research Funding; Daiichi-Sankyo: Research Funding; Astellas: Research Funding; Incyte: Consultancy; AbbVie: Consultancy, Research Funding; Kura Oncology: Research Funding; Genetech: Research Funding; Celgene: Research Funding; Forma Therapeutics: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Syros Pharmaceuticals: Research Funding. Germing:Novartis: Honoraria, Research Funding; Janssen: Honoraria; Celgene: Honoraria, Research Funding. Götze:Takeda: Honoraria, Other: Travel aid ASH 2017; Celgene: Honoraria, Research Funding; Novartis: Honoraria; JAZZ Pharmaceuticals: Honoraria. Quesnel:Celyad: Honoraria; Novartis: Honoraria; Astellas: Honoraria; Sunesis: Honoraria. Beyne-Rauzy:Novartis: Research Funding. Cluzeau:Amgen: 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; Sanofi: Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Menarini: Consultancy; Pfizer: Speakers Bureau. Voso:Celgene: Research Funding, Speakers Bureau. Zeidan:Otsuka: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Takeda: Honoraria, Speakers Bureau; Agios: Consultancy, Honoraria. Laadem:Celgene: Employment, Equity Ownership. Benzohra:Celgene: Employment, Equity Ownership. Zhang:Celgene: Employment, Equity Ownership. Rampersad:Celgene: Employment, Equity Ownership. Linde:AbbVie: Equity Ownership; Abbott Laboratories: Equity Ownership; Fibrogen: Equity Ownership; Acceleron Pharma: Employment, Equity Ownership. Sherman:Acceleron Pharma: Employment, Equity Ownership. Komrokji:Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding. List:Celgene: Research Funding.

Multiple myeloma (MM) evolves from a premalignant condition known as monoclonal gammopathy of undetermined significance (MGUS). However, the factors underlying the malignant transformation of plasmocytes in MM are not fully characterized. We report here that Eµ-directed expression of the antiapoptotic Bcl-B protein in mice drives an MM phenotype that reproduces accurately the human disease. Indeed, with age, Eµ-bcl-b transgenic mice develop the characteristic features of human MM, including bone malignant plasma cell infiltration, a monoclonal immunoglobulin peak, immunoglobulin deposit in renal tubules, and highly characteristic bone lytic lesions. In addition, the tumors are serially transplantable in irradiated wild-type mice, underlying the tumoral origin of the disease. Eµ-bcl-b plasmocytes show increased expression of a panel of genes known to be dysregulated in human MM pathogenesis. Treatment of Eµ-bcl-b mice with drugs currently used to treat patients such as melphalan and VELCADE efficiently kills malignant plasmocytes in vivo. Finally, we find that Bcl-B is overexpressed in plasmocytes from MM patients but neither in MGUS patients nor in healthy individuals, suggesting that Bcl-B may drive MM. These findings suggest that Bcl-B could be an important factor in MM disease and pinpoint Eµ-bcl-b mice as a pertinent model to validate new therapies in MM., Ligue nationale contre le cancer (France) (Equipe Labellisée Grant R08001AA), Fondation de France (Grant R08080AA), Fondation ARC pour la Recherche sur le Cancer (Grant PGA120140200777), Fondation ARC pour la Recherche sur le Cancer (Project 2015–2016), French Research National Agency (Grant ANR-11-LABX-0028-01)

Myelodysplastic syndromes are heterogeneous diseases whose molecular characteristics have only been identified in recent years. Better identification of prognostic factors, larger access to allogeneic stem cell transplantation and the advent of new drugs notably hypomethylating agents (azacitidine, decitabine) and lenalidomide have improved patient outcome.

Background. We previously reported that IL7R-pathway genes are mutated in 29% of T-ALL and that surface IL7R is expressed in 53% of T-ALL (Rathana K et al. abstract S131, EHA 2019). In these samples, in vitro and in vivo (IL7R+PDX T-ALL) sensitivity to JAK inhibitors is determined by the expression of IL7R regardless of the IL7Rp genomic status. BCL2 inhibition has been shown to be synergistic with the IL7R pathway inhibition (Degrise S et al., Leukemia 2018;32(3):788-800). We therefore explored whether the combination of tofacitinib, a potent JAK3 inhibitor, with venetoclax may improve the hematological status of patients with relapse/refractory T-ALL. Methods. Patients with relapse/refractory T-ALL, with surface IL7R expression or IL7R-pathway mutations and BCL2 expression were eligible if they had failed all available therapeutic options (including clofarabine and/or allogenic HSCT if eligible). Patients were offered to be treated with venetoclax, 100 mg/d day1; 200 mg/d day2; 300 mg/d day3 and 400 mg/day thereafter and for subsequent 28 days cycles combined with tofacitinib, 10mg twice a day started from day 5 cycle 1 (off-label use). Responses were assessed after cycle 1 and cycle 3. Responding patients may continue therapy until relapse, death or allogenic HSCT if eligible. Results. Eight patients were treated including 7 ETP-ALL and 1 T-cell lymphoblastic lymphoma. Median age was 56 years (27-69) and sex ratio (M/F) was 4/4. Four patients were refractory to at least 2 lines of therapy and 4 patients relapsed, all on therapy. Relapsing patients were in failure after at least one salvage therapy. All patients expressed BCL2. A mutation of JAK3 L857P was found in 5 cases including one patient with both JAK3 and JAK1 mutations. except one with a mutation of IL7-R. Other patients expressed IL7R. A response to therapy was observed in 5 out of seven evaluable cases (71%) including 2 CR associated with a negative MRD (sensitivity 10-4) and 3 partial responses (medullar blasts less than 15%). The remaining patient has just started the first cycle of therapy. Duration of responses was 10 months and +6 months (allo HSCT planned) for the 2 patients in CR and 3 months or less for the partial responders. No serious adverse event related to therapy was observed. Conclusion. IL7-pathway is a possible target for therapy with JAK inhibitors in patients with T-ALL in relapse or refractory to conventional therapy. A combination of venetoclax and tofacitinib may offer a potential savage for these patients with limited therapeutic options. Disclosures Chevallier: Daiichi Sankyo: Honoraria; Incyte: Consultancy, Honoraria; Jazz Pharmaceuticals: Honoraria. Dombret:Institut de Recherches Internationales Servier (IRIS): Research Funding; AGIOS: Honoraria; CELGENE: Consultancy, Honoraria. Boissel:NOVARTIS: Consultancy. Rousselot:Pfizer: Research Funding; Incyte: Research Funding. OffLabel Disclosure: Venetoclax in T-ALL Tofacitinib in T-ALL

Improvements in antisense technology have now enabled clinically relevant therapeutic credentialing of the noncoding genome. MALAT1 is a long non-coding RNA that, among other functions, is thought to serve as a nuclear scaffold for splicing and transcription factors. MALAT1 expression is associated with inferior prognosis across solid tumors and its depletion impairs proliferation and metastasis in preclinical solid tumor models. We found that elevated MALAT1 levels are independently associated with inferior overall survival in patients with CMML. Further, RNA-sequencing of primary CMML monocytes identified MALAT1 as the fourth most over-expressed transcript compared to controls. Therefore, we explored the biologic relevance and therapeutic candidacy of MALAT1 across several human and murine models of CMML. First, we crossed NRASQ61R/+Mx1-cre driven mice, which display a CMML-like phenotype, to MALAT1KO/KOmice. Although MALAT1KO/KOmice did not have abnormalities in complete blood counts, immunophenotyping of the hematopoietic stem cell (HSC) compartment identified statistically significantly lower numbers of HSC compared to wild type (WT) controls and a non-significant decrease in NRASQ61R/+/MALAT1KO/KOcompared to NRASQ61R/+alone. This decrease in HSC was not a result of impaired self-renewal as no differences were observed in these models after in vivo competitive transplant experiments. Therefore, we reasoned that MALAT1 expression may be controlling HSC differentiation. To test this, we transformed bone marrow cells from these models with an estrogen-regulated (ER) Hoxb8 construct enabling cells to maintain an HSC state until ER is withdrawn and myeloid differentiation is induced. ER-Hoxb8NRASQ61R/+/MALAT1KO/KOcells had increased basal levels of Gr-1 compared to ER-Hoxb8 transformed NRASQ61R/+alone that was dramatically enhanced upon ER withdrawal suggesting that MALAT1 depletion regulates myeloid differentiation. These findings were validated by assessment of morphology, transcriptome, and in vivo immunophenotyping of bone marrow and spleen cells. Further, moribund NRASQ61R/+/MALAT1KO/KOmice displayed a reduction in organomegaly typically associated with leukemic burden. We validated this in human monocytic leukemia by generating MALAT1 depleted THP-1 isogeneic cell lines using the CRISPR/Cas9 system. MALAT1 depleted THP-1 cells (MKO) had greater terminal differentiation according to immunophenotypic markers and morphology that was greatly enhanced when treated with phorbol myristate acetate. Last, MKO orthotopic xenografts demonstrated inferior human leukemia engraftment and decreased spleen and liver weights, and heterotopic xenografts exhibited reduced tumor volume, collectively suggesting diminished leukemic burden. Because ATRA has been clinically tested in CMML with minimal effects, we next explored whether MALAT1 depletion could potentiate ATRA differentiation in CMML. First, we treated MKO cells with ATRA and observed a large induction of myeloid differentiation by marker expression and morphologic assessment compared to isogenic controls. This was validated by NRASQ61R/+/MALAT1KO/KOmice demonstrating that ATRA more robustly induced differentiation compared to vehicle which was not seen in NRASQ61R/+/MALAT1+/+mice. Next, we tested MALAT1 antisense oligonucleotides (ASOs) currently under clinical development in THP-1 cells +/- ATRA and demonstrated both an increase in myeloid differentiation and apoptosis compared to ATRA alone. To test this therapeutic strategy in primary CMML specimens, we generated CMML patient-derived xenografts (n=30 mice) and treated each with ASO, ATRA, the combination, or controls and identified a more robust reduction in human HSC engraftment with the combination. To explore the mechanistic basis for these findings, we performed RNA-sequencing of MALAT1-depleted or control cells and identified that CREB target genes were differentially expressed. Basal protein levels of p-CREB were also decreased in MKO cells and were further reduced in the nucleus of MKO by western and microscopy. Lastly, overexpression of WT or constitutively active CREB but not its dominant negative rescued the differentiation effect seen in ATRA treated MKO cells. Taken together, MALAT1 is a novel, CREB-dependent regulator of myeloid differentiation and its depletion potentiates ATRA therapy. Disclosures Cluzeau: Menarini: Consultancy; Jazz Pharma: Consultancy; Abbvie: Consultancy. Komrokji:celgene: Consultancy; pfizer: Consultancy; DSI: Consultancy; JAZZ: Speakers Bureau; Novartis: Speakers Bureau; JAZZ: Consultancy; Agios: Consultancy; Incyte: Consultancy. MacLeod:Ionis Pharmaceuticals: Employment. List:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Epling-Burnette:Forma Therapeutics: Research Funding; Celgene Corporation: Patents & Royalties, Research Funding; Incyte Corporation: Research Funding.

Introduction: TP53 gene mutations (mTP53), found in up to 20% of MDS or AML pts and 30-40% of therapy-related (TR) MDS/AML cases, represent a distinct molecular cohort with poor outcomes. Hypomethylating agents (HMA) are the standard of care with CR rates of ~20% and median OS of 7-8 months. APR-246 is a novel, first-in-class small molecule that selectively induces apoptosis in mTP53 cancer cells via thermodynamic stabilization of the p53 protein and shifting equilibrium toward the wild-type conformation. We previously reported the Phase 1b results of APR-246+AZA with no DLTs, transcriptional activation of p53 targets and high response rates, identifying a Phase 2 (P2) dose of 4500mg days 1-4 (Sallman et al., ASH 2018). We report herein the planned, completed phase 2 results. Methods: This is a multicenter Phase 1b/2 trial of APR-246+AZA in HMA-naïve mTP53 higher risk MDS, MDS/MPN and oligoblastic AML (≤ 30% blasts) pts (NCT03072043). P2 pts received APR-246 4500mg IV (days 1-4) + AZA 75 mg/m2 SC/IV x 7 days (days 4-10 or 4-5 and 8-12) in 28 day cycles. Primary objective was CR rate by International Working Group (IWG) 2006 criteria. Secondary objectives included ORR, OS, outcome following allogeneic hematopoietic stem cell transplant (allo-HSCT), and both next generation sequencing (NGS) and p53 immunohistochemistry (IHC) to monitor clonal suppression and remission depth as prognostic covariates. For minimal residual disease (MRD) analysis, a custom target-capture NGS assay was developed using unique molecular Identifiers for error correction with a 0.1% limit of detection. Results: As of July 15, 2019, 55 pts were enrolled (6 P1; 49 P2) with a median age 66 years (34-85; 47% male). By WHO, 40 pts had MDS, 11 AML-MRC and 4 CMML/MDS-MPN; 85% had complex cytogenetics and 33% TR-MDS/AML. All pts had higher risk disease by IPSS-R (7% Intermediate, 24% High, 69% Very High). Fifty pts (91%) had a TP53 missense mutation in the DNA binding domain with multiple mutations in 18 (33%), and median variant allele frequency (VAF) of 25%. In 34 pts (62%), TP53 was the sole mutation. Median time on treatment is 154 days (11-392) with 8 pts ongoing. Eighteen pts (33%; 40% of evaluable pts) discontinued study treatment to proceed to allo-HSCT. Treatment (Tx)-related AEs in ≥ 20% of pts included nausea/vomiting (58%), dizziness (31%), constipation (24%), neuropathy (22%), leukopenia (22%) and thrombocytopenia (20%; all G1/G2 except cytopenias (G3/G4). Tx-related febrile neutropenia and anemia occurred in 9% and 5% of pts with no other G3/G4 event in >1 pt. Thirty and 60 day mortality was 2% (n=1) and 6% (n=3), respectively. At data cutoff, 45pts were response evaluable with a median follow up of 10.5 months (Fig 1A). ORR by IWG was 87% (39/45) with 24 CR (53%), 8 marrow CR (mCR)+HI (18%), 3 HI alone (7%), and 4 with mCR (9%). Of 6 non-responders, 4 had stable disease and 2 pts had progressive disease. Median time to response was 2.1 months (0.1-5.4) and median duration of response of 6.5 months. CR rate for MDS was 61% (20/33), 50% for AML (4/8) and 0% for MDS/MPN (0/4) with an 88% ORR rate for MDS/AML and 75% for MDS/MPN. An isolated mTP53 was predictive for a higher CR rate (69% vs 25%; P=.006) with a trend for higher ORR (93% vs 75%; P=.17). Additionally, pts with >10% p53 IHC+ BM-MNC was a covariate associated with higher CR rate (66% vs 13%; P=.01). Complete and partial cytogenetic response occurred in 41% (n=18) and 18% (n=8) of pts, respectively. On serial TP53 NGS using a VAF cutoff of 5%, 39% (n=21) of patients achieved NGS negativity, which was associated with improved OS (12.8 vs 9.2 months; P=.02). In NGS- pts, the median MRD VAF at maximum clearance was 0.63% (0.0%-5%) with 5 pts (11%) MRD negative. By intention-to-treat analysis, median OS was 11.6 months (95% CI 9.2-14) with significantly longer OS in responding pts (12.8 vs 3.9 months; P Conclusions: APR-246+AZA is a well-tolerated combination with high response rates in mTP53 MDS/AML. Response durations are promising accompanied by a high fraction of cytogenetic and deep molecular remissions leading to encouraging outcomes post-HSCT. These data support the ongoing, randomized phase 3 study of APR-246+AZA versus AZA alone in mTP53 MDS (NCT03745716). Disclosures Sallman: Abbvie: Speakers Bureau; Novartis: Speakers Bureau; Jazz: Research Funding; Incyte: Speakers Bureau; Celyad: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding, Speakers Bureau. DeZern:Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. Garcia-Manero:Amphivena: Consultancy, Research Funding; Helsinn: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Celgene: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Onconova: Research Funding; H3 Biomedicine: Research Funding; Merck: Research Funding. Steensma:Stemline: Consultancy; Pfizer: Consultancy; Aprea: Research Funding; H3 Biosciences: Other: Research funding to institution, not investigator.; Astex: Consultancy; Arrowhead: Equity Ownership; Onconova: Consultancy; Summer Road: Consultancy. Roboz:AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Actinium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amphivena: Consultancy, Membership on an entity's Board of Directors or advisory committees; Argenx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astex: 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; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Eisai: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees; Otsuka: 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; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Trovagene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Sekeres:Syros: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Cluzeau:Jazz Pharma: Consultancy; Abbvie: Consultancy; Menarini: Consultancy. Sweet:Incyte: Research Funding; Celgene: Speakers Bureau; Pfizer: Consultancy; Agios: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Jazz: Speakers Bureau; Stemline: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Korbel:Aprea Therapeutics: Employment. Attar:Aprea Therapeutics: Employment. Kantarjian:Astex: Research Funding; Amgen: Honoraria, Research Funding; Ariad: Research Funding; BMS: Research Funding; AbbVie: Honoraria, Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Immunogen: Research Funding; Jazz Pharma: Research Funding; Takeda: Honoraria; Pfizer: Honoraria, Research Funding; Daiichi-Sankyo: Research Funding; Agios: Honoraria, Research Funding; Cyclacel: Research Funding. Lancet:Daiichi Sankyo: Consultancy, Other: fees for non-CME/CE services ; Agios, Biopath, Biosight, Boehringer Inglheim, Celator, Celgene, Janssen, Jazz Pharmaceuticals, Karyopharm, Novartis: Consultancy; Pfizer: Consultancy, Research Funding. Fenaux:Aprea: Research Funding; Astex: Honoraria, Research Funding; Celgene Corporation: Honoraria, Research Funding; Jazz: Honoraria, Research Funding. List:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Komrokji:JAZZ: Consultancy; Novartis: Speakers Bureau; Incyte: Consultancy; DSI: Consultancy; pfizer: Consultancy; celgene: Consultancy; JAZZ: Speakers Bureau; Agios: Consultancy.

Introduction : TP53 mutated (TP53m) MDS and AML have very poor outcome irrespective of the treatment received, including 40% responses (20% CR) with azacitidine (AZA) with short response duration and a median overall survival (OS) of about 8 months (Bejar, Blood 2014). APR-246 is a prodrug spontaneously converted to methylene quinuclidinone (MQ), a Michael acceptor that binds covalently to cysteines in mutant p53, leading to protein reconformation that reactivates its pro apoptotic and cell cycle arrest functions. The combination of AZA and APR 246 showed promising results in a phase Ib study in TP53m MDS (Sallman, ASH 2018). We report interim results of a GFM phase 2 study of AZA+ APR-246 in TP53m MDS and AML, conducted in parallel with a similar US MDS consortium study. Patients and Methods : The study included hypomethylating agent (HMA) naïve and not previously allografted intermediate, high or very high IPSS-R TP53m MDS and AML adult patients. Patients received APR-246 4500 mg IV /d (6 hour infusions) (days 1-4) followed by AZA 75 mg/m²/d (days 4-10) in 28 day cycles. Response (primary endpoint, assessed by IWG 2006 for MDS and ELN criteria for AML) was evaluated after 3 and 6 cycles in the intent to treat (ITT) population, ie all patients who had received any protocol treatment, and in patients who had at least a blood and bone marrow evaluation after cycle 3 (evaluable population). Allo-SCT, when possible, was proposed after 3 to 6 cycles, and treatment with reduced APR 246 and AZA doses could be continued after allo-SCT. Results : 53 patients were enrolled between Sept 2018 and July 2019 in 7 GFM centers, with a median age of 73 years (range 44-87), and M/F: 28/25. 34 patients had MDS (including 74% very high IPSS-R) and 19 had AML. IPSS-R cytogenetic risk was very poor in 30/34 MDS, and unfavorable in 18/19 AML, complex in 89% of the patients. Median baseline mutated TP53 VAF was 21% (range 3-76). Nineteen of the 53 patients had been included at least 7 months before date of analysis (25 July 2019), had received protocol treatment and were thus potentially evaluable for response after 6 treatment cycles (ITT population). One of them died after only one cycle from an unrelated cause (cerebral ischemic stroke), and 2 during the third cycle (from bleeding and sepsis, respectively). In the remaining 16 patients (evaluable population per protocol), the response rate was 75% including 9 (56%) CR, 3 (19%) marrow CR or stable disease with hematological improvement (HI), and 4 treatment resistance. In the ITT population, the response rate was 63%, including 47% CR, and 16% stable or marrow CR+ HI. Among CR patients, complete cytogenetic CR and negative NGS for TP53 mutation (VAF cutoff of 2%) were achieved in 7/9 (78%) and 8/8 (100%), respectively. So far, 1 patient has undergone allo-SCT. All 53 patients had received at least one treatment cycle, and no increased myelosuppression, compared with AZA alone, was apparent. Treatment related AEs observed in ≥ 20% of patients were febrile neutropenia in 19 (36%) and neurological AEs in 21 (40%) of the patients. The latter, reviewed with a neurological team, were mainly grade 1 or 2 and consisted of ataxia (n=13), sometimes associated with cognitive impairment (n=4), suggesting a cerebellar origin. Other patients experienced acute confusion (n=4), isolated dizziness (n=3) and facial paresthesia (n=1). Neurological AEs reached grade III in 3 cases (1 acute confusion, 2 ataxia). Occurrence of neurological AEs was correlated with lower glomerular filtration rate at treatment onset (p Conclusion : In this very high-risk elderly population of TP53m MDS and AML, generally with complex karyotype, a promising 56% CR rate at 6 cycles was reached in the evaluable population with AZA+ APR 246 combination, with deep molecular remission in all CR patients. We observed manageable neurologic AEs, mainly in elderly patients with reduced renal function, who therefore require close monitoring and dose reduction if necessary. An update regarding safety and efficacy in the 53 patients, including survival data, will be available at the meeting. A phase III international trial comparing AZA alone and AZA+ APR 246 in TP53m MDS is ongoing. Disclosures Cluzeau: Abbvie: Consultancy; Jazz Pharma: Consultancy; Menarini: Consultancy. Peterlin:AbbVie Inc: Consultancy; Astellas: Consultancy; Jazz Pharma: Consultancy; Daiichi-Sankyo: Consultancy. Recher:Daiichi-Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; chugai: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Astellas Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stamatoullas:Celgene: Honoraria; Takeda: Consultancy. Berthon:JAZZPHARMACEUTICAL: Other: DISCLOSURE BOARD; CELGEN: Other: DISCLOSURE BOARD; PFIZER: Other: DISCLOSURE BOARD. Sallman:Celyad: Membership on an entity's Board of Directors or advisory committees. Ades:Amgen: Research Funding; Astellas: Membership on an entity's Board of Directors or advisory committees; Silence Therapeutics: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Fenaux:Celgene Corporation: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Aprea: Research Funding.

Chaperone-mediated autophagy (CMA) is a highly selective form of autophagy. During CMA, the HSC70 chaperone carries target proteins endowed with a KFERQ-like motif to the lysosomal receptor LAMP2A, which then translocate them into lysosomes for degradation. In the present study, we scrutinized the mechanisms underlying the response and resistance to Azacytidine (Aza) in MDS/AML cell lines and bone marrow CD34+ blasts from MDS/AML patients. In engineered Aza-resistant MDS cell lines and some AML cell lines, we identified a profound defect in CMA linked to the absence of LAMP2A. LAMP2 deficiency was responsible for Aza resistance and hypersensitivity to lysosome and autophagy inhibitors. Accordingly, gain of function of LAMP2 in deficient cells or loss of function in LAMP2-expressing cells rendered them sensitive or resistant to Aza, respectively. A strict correlation was observed between the absence of LAMP2, resistance to Aza and sensitivity to lysosome inhibitors. Low levels of LAMP2 expression in CD34+ blasts from MDS/AML patients correlated with lack of sensitivity to Aza and were predictive of poor overall survival. We propose that CD34+/LAMP2Low patients at diagnosis or who become CD34+/LAMP2Low during the course of treatment with Aza might benefit from a lysosome inhibitor already used in the clinic.

Although hypomethylating agents (HMAs) are frequently used in the frontline treatment of older acute myeloid leukemia (AML) patients, little is known about their effectiveness in relapsed or primary treatment–refractory (RR)-AML. Using an international multicenter retrospective database, we studied the effectiveness of HMAs in RR-AML and evaluated for predictors of response and overall survival (OS). A total of 655 patients from 12 centers received azacitidine (57%) or decitabine (43%), including 290 refractory (44%) and 365 relapsed (56%) patients. Median age at diagnosis was 65 years. Best response to HMAs was complete remission (CR; 11%) or CR with incomplete count recovery (CRi; 5.3%). Additionally, 8.5% experienced hematologic improvement. Median OS was 6.7 months (95% confidence interval, 6.1-7.3). As expected, OS differed significantly by best response, with patients achieving CR and CRi having a median OS of 25.3 and 14.6 months, respectively. In multivariate analysis, the presence of ≤5% circulating blasts and a 10-day schedule of decitabine were associated with improved response rates, whereas the presence of >5% circulating blasts and >20% bone marrow blasts were associated with decreased OS. A significant subset of RR-AML patients (16%) achieved CR/CRi with HMAs and experienced a median OS of 21 months. Outside of a clinical trial, HMAs represent a reasonable therapeutic option for some patients with RR-AML.

Item does not contain fulltext Most studies of immunosuppressive therapy (IST) in myelodysplastic syndromes (MDS) are limited by small numbers and their single-center nature, and report conflicting data regarding predictors for response to IST. We examined outcomes associated with IST and predictors of benefit in a large international cohort of patients with MDS. Data were collected from 15 centers in the United States and Europe. Responses, including red blood cell (RBC) transfusion independence (TI), were assessed based on the 2006 MDS International Working Group criteria, and overall survival (OS) was estimated by Kaplan-Meier methods. Logistic regression models estimated odds for response and TI, and Cox Proportional Hazard models estimated hazards ratios for OS. We identified 207 patients with MDS receiving IST, excluding steroid monotherapy. The most common IST regimen was anti-thymocyte globulin (ATG) plus prednisone (43%). Overall response rate (ORR) was 48.8%, including 11.2% (95% confidence interval [CI], 6.5%-18.4%) who achieved a complete remission and 30% (95% CI, 22.3%-39.5%) who achieved RBC TI. Median OS was 47.4 months (95% CI, 37-72.3 months) and was longer for patients who achieved a response or TI. Achievement of RBC TI was associated with a hypocellular bone marrow (cellularity < 20%); horse ATG plus cyclosporine was more effective than rabbit ATG or ATG without cyclosporine. Age, transfusion dependence, presence of paroxysmal nocturnal hemoglobinuria or large granular lymphocyte clones, and HLA DR15 positivity did not predict response to IST. IST leads to objective responses in nearly half the selected patients with the highest rate of RBC TI achieved in patients with hypocellular bone marrows.

Altres ajuts: National Cancer Institute/National Institute of Health (5 R01CA131076-04); Molecular Genomics Facility (P30-CA076292); Sociedad Española Hematología y Hemoterapia (2014 SGR225); Fundació Internacional Josep Carreras i Celgene Spain. RTICC/RD12/0036/0044 Abstract:P53 is a key regulator of many cellular processes and is negatively regulated by the human homolog of murine double minute-2 (MDM2) E3 ubiquitin ligase. Single nucleotide polymorphisms (SNPs) of either gene alone, and in combination, are linked to cancer susceptibility, disease progression, and therapy response. We analyzed the interaction of TP53 R72P and MDM2 SNP309 SNPs in relationship to outcome in patients with myelodysplastic syndromes (MDS). Sanger sequencing was performed on DNA isolated from 208 MDS cases. Utilizing a novel functional SNP scoring system ranging from +2 to -2 based on predicted p53 activity, we found statistically significant differences in overall survival (OS) (p = 0.02) and progression-free survival (PFS) (p = 0.02) in non-del(5q) MDS patients with low functional scores. In univariate analysis, only IPSS and the functional SNP score predicted OS and PFS in non-del(5q) patients. In multivariate analysis, the functional SNP score was independent of IPSS for OS and PFS. These data underscore the importance of TP53 R72P and MDM2 SNP309 SNPs in MDS, and provide a novel scoring system independent of IPSS that is predictive for disease outcome.

In recent years, the outcome of Burkitt leukemia/lymphoma (BL) has improved significantly. Central nervous system (CNS) involvement continues to be a poor prognostic indicator. High doses of intravenous polychemotherapy, intrathecal chemotherapy, and cranio-spinal radiation therapy are used by numerous groups. Majority of patients are cured after this strategy. The next challenge is to decrease toxicities of treatment, including long-term toxicities secondary to cranio-spinal radiation therapy observed in these cured patients. Liposomal cytarabine could be a good alternative to cranio-spinal radiation therapy as already reported in acute lymphoblastic leukemia. We report here eleven patients treated in our center for BL, with liposomal cytarabine instead of cranio-spinal radiation therapy as prophylactic or curative treatment for CNS involvement. Treatment was safe with no short-term grade >3 adverse events. Moreover, no long-term side effects and no impact on outcome were observed. We conclude that LC could be a good option to decrease short/long-term side effects of cranio-spinal radiation therapy in BL and could be evaluated in a future clinical trial.

IF 2.501; International audience; 60-70% of AML patients have an indication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) during their treatment. Graft versus host disease (GvHD), the major cause of mortality and comorbidities post-transplantation, develops by immunological mechanism and decides greatly prognosis and quality of life (QoL) of graft recipient. Current GvHD prophylaxis is not personalized. Infections, toxicities and leukemic infiltration complicate the first chemotherapy phases prior to allo-HSCT. They, to certain extent, induce local immune stimulation. Impact of immune stimulation of this period on incidence of GvHD has not been evaluated. We retrospectively studied 238 AML patients transplanted at first remission from 21 French centers in the ALFA-0702 protocol and found that cutaneous and digestive immune stimulation during induction increases the incidence of skin and gut aGVHD, respectively. Furthermore, prolonged febrile duration correlates with elevated incidence of grade II-IV aGvHD. Thus, we identified a group of patients with higher risk of aGvHD. The benefit of personalized GvHD prophylaxis should be explored in a prospective cohort to decrease incidence of aGvHD in these patients and improve their QoLs.

// Thomas Cluzeau 1,2,3,4,6,* , Alix Dubois 1,2,3,4,* , Arnaud Jacquel 1,2,3,4 , Frederic Luciano 1,2,3,4 , Aline Renneville 5 , Claude Preudhomme 5 , Jean Michel Karsenti 6 , Nicolas Mounier 6 , Pierre Rohrlich 6 , Sophie Raynaud 7 , Bernard Mari 8 , Guillaume Robert 1,2,3,4 and Patrick Auberger 1,2,3,4,6 1 INSERM U1065, Mediterranean Center for Molecular Medicine (C3M), Nice, France 2 INSERM U1065, Team 2: Cell Death, Differentiation, Inflammation and Cancer 3 Equipe labellisee par la Ligue Nationale Contre le Cancer (2011-2013), Paris, France 4 University of Nice, Nice, France 5 Laboratory of Hematology, Biology and Pathology Center, CHRU of Lille, Lille, France 6 Department of Clinical hematology and Transplantation, CHU of Nice, Nice, France 7 Oncohematology laboratory, CHU of Nice, Nice, France 8 Molecular and Cellular Pharmacology Institute, CNRS, Sophia-Antipolis, France * These authors participated equally to this work Correspondence: Patrick Auberger, email: // Keywords : MDS, AML, Azacitidine, Polyploidy, TET2, ASLX1 Received : May 5, 2014 Accepted : May 26, 2014 Published : May 27, 2014 Abstract In the present study, we provide a comparative phenotypic and genotypic analysis of azacitidine-sensitive and resistant SKM-1 cell lines. Morphologically, SKM1-R exhibited increase in cell size that accounts for by enhanced ploidy in a majority of cells as shown by cell cycle and karyotype analysis. No specific Single Nucleotide Polymorphism (SNP) alteration was found in SKM1-R cells compared to their SKM1-S counterpart. Comparative pangenomic profiling revealed the up-regulation of a panel of genes involved in cellular movement, cell death and survival and down-regulation of genes required for cell to cell signaling and free radical scavenging in SKM1-R cells. We also searched for mutations frequently associated with myelodysplastic syndromes (MDS) and found that both cell lines harbored mutations in TET2, ASLX1 and TP53. Collectively, our data show that despite their different morphological and phenotypic features, SKM1-S and SKM1-R cells exhibited similar genotypic characteristics. Finally, pangenomic profiling identifies new potential pathways to be targeted to circumvent AZA-resistance. In conclusion, SKM1-R cells represent a valuable tool for the validation of new therapeutic intervention in MDS.

Introduction: TP53 mutant (mTP53) MDS and AML, accounting for 5-10% of de novo MDS and 25-30% of therapy related MDS (t-MDS), represent a distinct molecular cohort with inferior outcomes. Hypomethylating agents (HMA) are preferred treatments for patients (pts) with these mutations, although with CR rates of only 20-30% and median OS of 6-12 months. APR-246 is a novel, first-in-class small molecule that selectively induces apoptosis in mTP53 cancer cells through mutant p53 protein re-activation by restoring the wild-type conformation, with single agent activity in mTP53 AML. We report the planned, completed Phase 1b results of APR-246+ azacitidine (AZA) in mTP53 MDS/AML. Methods: This is a multicenter Phase 1b/2 trial of APR-246+AZA in HMA naïve mTP53 MDS and oligoblastic AML (≤ 30% blasts) pts ≥ 18 years of age. Pts received APR-246 in a 3+3 dose escalation design (50, 75, 100 mg/kg lean body weight (equivalent to 4500mg fixed dose based on PK studies)) IV daily over 4 days in a lead-in phase (days -14 to -10) followed by the same dose of APR-246 (days 1-4) + AZA 75 mg/m2 SC/IV over 7 days (days 4-10 or 4-5 and 8-12) in 28 day cycles. The primary objective was to define safety and the recommended Phase 2 dose (RP2D), with AEs graded by CTCAE v4.03 and DLT assessment over 6 weeks. Secondary objectives included response by IWG 2006 criteria as well as serial next generation sequencing (NGS) and p53 IHC for evaluation of clonal suppression and remission depth as predictors of outcomes. For minimal residual disease (MRD) analysis, a custom target-capture NGS assay was developed using unique molecular Identifiers for error correction with a limit of detection of 0.1% with results validated by pt specific digital droplet PCR (ddPCR). Nanostring nCounter RNA expression analysis was conducted on a panel of 770 genes after the lead-in phase to assess transcriptional effects induced by APR-246. Results: As of July 30, 2018, 12 pts (42% male; median age 66 years (39-73)) were enrolled. Three pts had AML-MRC and 9 had MDS; all pts had poor risk cytogenetics (17% poor, 83% very poor) and higher risk disease by IPSS-R (25% high, 75% very high). T-MDS occurred in 5 pts (42%) and 7 pts (58%) were transfusion-dependent at baseline. Median BM blasts were 9% (4-30). Eleven of 12 pts (92%) had a TP53 missense mutation in the DNA binding domain with multiple mutations in 4/12 pts (33%). For 9/12 pts (75%), TP53 was the sole mutation. Median time on study is 176 days (41-298) with 7 pts ongoing. Treatment (Tx) related AEs during the lead-in phase (all G1) included nausea (n=5), neuropathy (n=5), decreased appetite (n=2), and dizziness (n=2) which were all transient. Tx related AEs occurring in > 1 pt in the combination phase included nausea/vomiting (n=6), dizziness (n=3), headache (n=3), neuropathy (n=3), fall (n=2), pruritus (n=2), thrombocytopenia (n=6), neutropenia (n=5), and leukopenia (n=4); all G1/G2 except cytopenias (G3/G4). No DLTs have occurred to date. Eleven of twelve pts were response evaluable with 1 pt discontinuing tx prior to 1st disease assessment (Fig 1A). ORR by IWG was 100% (11/11) with 9 CR (82%) and 2 marrow CR (mCR; 18%). Median time to first response was 70 days (4-91) and one CR patient achieved mCR and partial cytogenetic response after APR-246 lead-in prior to combination therapy. All CR pts had high p53 positivity by IHC at baseline (25-80%) which normalized on serial assessment with the 2mCR pts having Conclusions: APR-246+AZA combination is well tolerated in mTP53 MDS/AML. Responses have been achieved in all evaluable pts (82% CR) accompanied by deep molecular and durable remissions. The RP2D of APR-246 is a fixed dose of 4500mg days 1-4 in combination with AZA and phase 2 accrual has begun. Disclosures Sallman: Celgene: Research Funding, Speakers Bureau. Sweet:Agios: Consultancy; Phizer: Consultancy; Agios: Consultancy; BMS: Honoraria; Celgene: Honoraria, Speakers Bureau; Jazz: Speakers Bureau; Celgene: Honoraria, Speakers Bureau; BMS: Honoraria; Phizer: Consultancy; Novartis: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Astellas: Consultancy; Jazz: Speakers Bureau; Astellas: Consultancy. Cluzeau:Celgene: Consultancy, 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, Speakers Bureau; Pfizer: Speakers Bureau; Sanofi: Speakers Bureau; Menarini: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Sekeres:Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Roboz:Orsenix: Consultancy; Cellectis: Research Funding; Eisai: Consultancy; Astex Pharmaceuticals: Consultancy; Argenx: Consultancy; Pfizer: Consultancy; Bayer: Consultancy; Eisai: Consultancy; Sandoz: Consultancy; Jazz Pharmaceuticals: Consultancy; Jazz Pharmaceuticals: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Otsuka: Consultancy; Bayer: Consultancy; Aphivena Therapeutics: Consultancy; Celltrion: Consultancy; Argenx: Consultancy; Celgene Corporation: Consultancy; Daiichi Sankyo: Consultancy; Celltrion: Consultancy; Sandoz: Consultancy; Astex Pharmaceuticals: Consultancy; Aphivena Therapeutics: Consultancy; Orsenix: Consultancy; Otsuka: Consultancy; Roche/Genentech: Consultancy; Roche/Genentech: Consultancy; Janssen Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Novartis: Consultancy; AbbVie: Consultancy; Janssen Pharmaceuticals: Consultancy; Celgene Corporation: Consultancy; AbbVie: Consultancy; Cellectis: Research Funding. Bhagat:Genoptix: Employment. Tell:Aprea Therapeutics: Employment. Fenaux:Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Jazz: Honoraria, Research Funding; Otsuka: Honoraria, Research Funding; Roche: Honoraria. List:Celgene: Research Funding. Komrokji:Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau.

BACKGROUND Post myeloproliferative neoplasms (MPN) acute myeloid leukemia (AML) occurs respectively in 1.5%, 7.0% and 11% of patients with essential thrombocytosis (ET), polycythemia vera (PV) and primary myelofibrosis (PMF). This subgroup of AML has very poor prognosis and are often excluded from clinical trials. Therefore, only few cohorts including molecular data are available. MATERIAL AND METHODS We retrospectively collected data from 111 patients treated in four centers in France for post MPN-AML. Clinical, molecular and treatment information was available for all patients at AML and MPN stages. DNA was extracted from samples at diagnosis of MPN chronic phase, at diagnosis of AML phase and after induction treatment. JAK2-V617F mutations were identified by qPCR (Ipsogen® MutaQuant kit, Qiagen, Germany), MPL-W515L/K mutations were identified by PCR (Ipsogen® MutaScreen kit, Qiagen, Germany) and CALR mutations were identified by conventional sequencing (Applied Biosystems, 3500Genetic Analyzer). NGS on 36 genes using Ampliseq librairy and Ion Proton sequencing (Thermofisher, Waltham, MA, USA) were performed in 96/111 patients. Overall response rate (ORR) was defined by complete remission (CR), CR with incomplete hematologic recovery (CRi), partial remission (PR) and stable disease (SD). Overall survival (OS) was calculated from the date of AML diagnosis to the date of death or last follow-up. All statistical analyses were performed using SPSS v.22 software (IBM SPSS Statistics). RESULTS 111 patients treated for post MPN-AML were retrospectively included in this study. Sex ratio M/F was 54%/46%. Median age at AML diagnosis was 66 years (28-89, range). Cytogenetic categories were favorable, intermediate and adverse in 2 (2%), 51 (46%) and 47 (42%) patients, respectively. 25/111 (23%) patients had a monosomal karyotype (MK). Median number of additional mutations excluding from JAK2/MPL/CALR mutations was 2 (0-6, range). The most frequent additional mutations were TP53 (23%), ASXL1 (17%), TET2 (13%), SRSF2 (10%), DNMT3A (8%), SF3B1 (8%) and RUNX1 (8%). Only 2 patients were mutated for NPM1 and 2 and 4 patients were FLT3-ITD and FLT3-TKD, respectively. Prior MPN were PV, ET and PMF in 20%, 34% and 46% of patients, respectively. First line treatment was intensive chemotherapy (IC) for 61 (55%) patients, hypomethylating agents (HMA) for 10 (9%) or other treatments including best supportive care, cytoreduction for the other ones. 24/111 (22%) underwent to ASCT. ORR was 54% (with 30/71 (42%) in CR/CRi) in patients treated by IC or HMA. We did not identify factors predicting a higher rate of CR/CRi. OS was 12 months [6-18] and was not influenced by transplant, cytogenetic categories or by the type and allele frequencies of JAK2/CALR/MPL mutations. OS was significantly longer in the group treated with HMA as compared to IC (10 versus 46 months, respectively, p=0.006); in patients with prior PV as compared to ET or MF (26 months [0-57] versus 10 months [7-13] versus 10 months [4-16] respectively, p=0.07) and in patients with presence of additional mutations other than JAK2/CALR/MPL (5 months [0-12] versus 46 months [32-60] in 38 patients without mutation versus 58 patients with presence of at least one mutation, respectively, p=0.04). By multivariate analysis, only presence of additional mutations was predictive for OS with a hazard ratio (HR) = 0.42 [0.18-0.97] (p=0.04). Finally, we followed the VAFs of JAK2 in seven patients before and after IC. We observed in 2 patients an increase of JAK2 clone correlated with CR whereas no variation of VAFs was associated with absence of CR. CONCLUSIONS In conclusion, we confirmed the poor prognosis of post MPN AML. Classical AML prognostic factors were not validated in our cohort. We identified the presence of mutations other than JAK2/MPL/CALR as the main prognostic factor whereas post-PV AML appeared to do better than post-ET and post-PMF AML. The very poor result of IC with or without ASCT highlights the need to develop specific clinical trials in this subgroup of AML. Disclosures Kuykendall: Celgene: Honoraria; Janssen: Consultancy. Sallman:Celgene: Research Funding, Speakers Bureau. Cluzeau:CELGENE: Consultancy; MENARINI: Consultancy; JAZZ PHARMA: Consultancy.

Introduction: Hyperleukocytosis, defined as a white blood cell count (WBC) of >50 × 109/L or >100 × 109/L, is seen in newly diagnosed AML and often results in leukostasis, increased risk of complications, and potentially early death. Those pts often require urgent evaluation and therapy. Leukapheresis is also sometimes used despite limited evidence supporting its use. There is limited data regarding the impact of time (day/night) and day (weekday/weekend) of admission and time to initiation of IC on outcomes in pts with hyperleukocytosis. Methods: Data were collected from 12 centers in USA and Europe (EU). Eligible pts had newly diagnosed AML, presented with a WBC > 50 × 109/L, and received IC. Univariate and multivariable logistic regression models stratified by centers (EU vs. USA) estimated odds ratios for death during induction (30-day mortality) and achievement of composite complete response (CRc) defined as CR+CR with incomplete count recovery (CRi). Univariate and multivariate Cox proportional hazard models stratified by centers (EU vs. USA) estimated hazards ratios (HR) for overall survival (OS). We evaluated the impact of leukapheresis, day of presentation (weekend vs. weekday), time of presentation (nighttime = 6pm-6am vs. daytime=6am-6pm), and time to initiation of IC. Studied covariates included age, Eastern Cooperative Oncology group performance status (ECOG PS), cytogenetics and molecular abnormalities, WBC, hemoglobin, platelet count, bone marrow and blood blast percentage, and presence of clinical leukostasis, tumor lysis syndrome (TLS) or disseminated intravascular coagulation (DIC) at presentation. Results: Among 1050 pts with AML and hyperleukocytosis whose data were collected, 787 were reported to have received IC and were included in this analysis. Of 787 pts receiving IC, 16.6% (95%CI, 13.9-19.3%) died during the first 30 days of IC. Leukapheresis was used in 117 pts (15%) in 8 of the 12 centers. In univariate analyses, neither weekend nor nighttime presentation nor use of leukapheresis impacted odds of death in the first 30 days. In multivariate analysis, higher odds of death during first 30 days were associated with age ³ 55 years (OR 3.2, p=0.015), ECOG PS ³ 2 (OR 4.4, 0.004), WBC > 100 × 109/L (OR 6.0, p=0.01) and presence of leukostasis (OR 4.5, p=0.005) and TLS (HR, 3.2, p=0.049). However, neither initiation of IC beyond 48 hours of presentation (vs. less than 48 hours) or use of leukapheresis significantly affected the odds of death in first 30 days (Figure 1A). Median OS of the entire cohort was 12.6 months (95%CI, 11.5-14.9) (Figure 2A). In multivariate analyses, age ³ 55 years (HR 2.6, p Conclusions: In this very large international cohort of newly diagnosed AML pts who presented with hyperleukocytosis and treated with IC, neither day (weekend vs weekday) nor time (day vs night) nor the use of leukapheresis had significant impact on odds of death during the first 30 days or on OS. Our data further highlight the limited evidence behind use of leukapheresis and support the urgent need to conduct randomized clinical trials to study any of its benefits. Disclosures Montesinos: Novartis: Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Speakers Bureau. Bhatt:Pfizer: Consultancy; CSL Behring: Consultancy; Incyte: Research Funding. Sekeres:Celgene: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Fathi:Celgene: Consultancy, Honoraria, Research Funding; Agios: Honoraria, Research Funding; Astellas: Honoraria; Boston Biomedical: Consultancy, Honoraria; Jazz: Honoraria; Seattle Genetics: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Khan:Teva: Speakers Bureau. Roboz:Janssen Pharmaceuticals: Consultancy; Bayer: Consultancy; Argenx: Consultancy; Astex Pharmaceuticals: Consultancy; Janssen Pharmaceuticals: Consultancy; Eisai: Consultancy; Eisai: Consultancy; Pfizer: Consultancy; Roche/Genentech: Consultancy; Bayer: Consultancy; Aphivena Therapeutics: Consultancy; Orsenix: Consultancy; Novartis: Consultancy; AbbVie: Consultancy; Celltrion: Consultancy; AbbVie: Consultancy; Daiichi Sankyo: Consultancy; Argenx: Consultancy; Sandoz: Consultancy; Aphivena Therapeutics: Consultancy; Jazz Pharmaceuticals: Consultancy; Orsenix: Consultancy; Jazz Pharmaceuticals: Consultancy; Astex Pharmaceuticals: Consultancy; Roche/Genentech: Consultancy; Sandoz: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Celgene Corporation: Consultancy; Daiichi Sankyo: Consultancy; Cellectis: Research Funding; Cellectis: Research Funding; Otsuka: Consultancy; Otsuka: Consultancy; Celltrion: Consultancy; Celgene Corporation: Consultancy. Cluzeau:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Menarini: Consultancy; Sanofi: Speakers Bureau. Germing:Novartis: Honoraria, Research Funding; Janssen: Honoraria; Celgene: Honoraria, Research Funding. Mukherjee:LEK Consulting: Consultancy, Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria; Projects in Knowledge: Honoraria; Takeda Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squib: Honoraria, Speakers Bureau; BioPharm Communications: Consultancy; Aplastic Anemia & MDS International Foundation in Joint Partnership with Cleveland Clinic Taussig Cancer Institute: Honoraria. Brunner:Novartis: Research Funding; Takeda: Research Funding; Celgene: Consultancy, Research Funding. Ritchie:NS Pharma: Research Funding; Astellas Pharma: Research Funding; Bristol-Myers Squibb: Research Funding; ARIAD Pharmaceuticals: Speakers Bureau; Novartis: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding; Celgene: Consultancy, Other: Travel, Accommodations, Expenses, Speakers Bureau; Incyte: Consultancy, Speakers Bureau. Podoltsev:Daiichi Snakyo: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; Astellas Pharma: Research Funding; Astex Pharmaceuticals: Research Funding; Celator: Research Funding; Boehringer Ingelheim: Research Funding; Pfizer: Research Funding; LAM Therapeutics: Research Funding; Sunesis Pharmaceuticals: Research Funding; Celgene: Research Funding; Genentech: Research Funding. Gore:Celgene: Consultancy, Research Funding. Zeidan:AbbVie: Consultancy, Honoraria; Takeda: Honoraria, Speakers Bureau; Agios: Consultancy, Honoraria; Otsuka: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria.

Introduction: Hyperleukocytosis at time of acute myeloid leukemia (AML) diagnosis is associated with increased disease-related complications as well as early mortality. Many AML patients are not candidates for intensive chemotherapy (IC) because of disease-related or patient-specific factors. Limited data is available regarding the characteristics and outcomes of newly-diagnosed AML who present with hyperleukocytosis and do not receive IC. Methods: We retrospectively analyzed data from patients with newly-diagnosed AML and hyperleukocytosis (defined as white blood cell count [WBC] of 50 × 109/L or greater) who were reported not to have received IC at 12 major institutions in the United States, Spain, Germany and France from 1982 to the end of 2016. Collected variables included age, sex, Eastern Cooperative Oncology Group Performance Status (ECOG PS), WBC, hemoglobin level, platelet count, renal and hepatic chemistry parameters, cytogenetic risk group, molecular abnormalities (if available), presence of tumor lysis syndrome (TLS), disseminated intravascular coagulation (DIC), clinical evidence of leukostasis, admission to an intensive care unit (ICU) at presentation, receipt of hydroxyurea, and administration of leukapheresis. Clinical evidence of leukostasis was defined as new onset hypoxia, chest pain, headache, focal neurological symptoms, priapism, intestinal ischemia and acute renal failure attributed to hyperleukocytosis by the primary provider of the patient. Kaplan-Meier analysis was used to estimate overall survival (OS) from time of presentation until death or end of follow-up. Patients with hyperleukocytosis who received IC are described in a separate abstract. Results: Of 1050 patients with AML and hyperleukocytosis reported to our dataset, 220 patients were reported not to have received IC and were included in this analysis. For those 220 patients, median age was 75 years, 57.7% were male, and most (62.8%) had an ECOG PS of 2 or greater. Median WBC, hemoglobin, and platelet count at presentation were 131.4 × 109/L (range [R], 50.4-620), 8.96 g/dL (R, 3.6-15.9), and 34 (R, 3-393), respectively; 61.5% presented with a WBC greater than 100 × 109/L. Cytogenetically-defined poor risk AML was diagnosed in 26.1% of patients. TLS, DIC or clinical leukostasis was present in 25.6%, 15.7%, and 32.5% of patients, respectively. Pulmonary, central nervous system, renal, cardiac, gastrointestinal, or retinal clinical evidence of leukostasis was present in 52.9%, 17.1%, 11.4%, 10%, 5.7% and 2.9%, respectively, of those with clinical leukostasis. The majority (72.9%) of patients received initial therapy with hydroxyurea with a median time from presentation to administration of 12 hours (R, 1-144). Only 15% of patients underwent leukapheresis. Commonly-used non-IC therapies included hypomethylating agents, clofarabine, low dose cytarabine, or best supportive care. The median OS of the entire cohort was only 22 (95%CI: 13-37) days. The 30-day mortality was 57.4%. The 60-day, 90-day, 180-day, and one-year OS probabilities were 37%, 31%, 20%, and 12%, respectively. Only 4.3% of patients proceeded to allogeneic stem cell transplant. Patients presenting with WBC >100 × 109/L (N=79) had a worse OS than those presenting with WBC Conclusions: We report the largest studied cohort of patients with newly-diagnosed AML presenting with hyperleukocytosis who did not receive IC. Outcomes were very poor with a median OS of 22 days and only 12% alive at one year. WBC >100K x 109/L and clinical leukostasis were associated with inferior survival, while leukapheresis did not seem to impact survival. Novel and effective therapies are urgently needed for this group of AML patients. Disclosures Montesinos: Daiichi Sankyo: Consultancy, Speakers Bureau; Novartis: Research Funding, Speakers Bureau. Bhatt:Incyte: Research Funding; CSL Behring: Consultancy; Pfizer: Consultancy. Sekeres:Opsona: Membership on an entity's Board of Directors or advisory committees; Opsona: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Fathi:Agios: Honoraria, Research Funding; Astellas: Honoraria; Boston Biomedical: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Jazz: Honoraria; Seattle Genetics: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Khan:Teva: Speakers Bureau. Roboz:AbbVie: Consultancy; Cellectis: Research Funding; Celltrion: Consultancy; Argenx: Consultancy; Aphivena Therapeutics: Consultancy; Eisai: Consultancy; Novartis: Consultancy; Otsuka: Consultancy; Astex Pharmaceuticals: Consultancy; Bayer: Consultancy; Celgene Corporation: Consultancy; Cellectis: Research Funding; Roche/Genentech: Consultancy; Roche/Genentech: Consultancy; Eisai: Consultancy; Aphivena Therapeutics: Consultancy; Otsuka: Consultancy; Pfizer: Consultancy; Sandoz: Consultancy; Sandoz: Consultancy; Orsenix: Consultancy; AbbVie: Consultancy; Janssen Pharmaceuticals: Consultancy; Astex Pharmaceuticals: Consultancy; Celltrion: Consultancy; Janssen Pharmaceuticals: Consultancy; Jazz Pharmaceuticals: Consultancy; Celgene Corporation: Consultancy; Orsenix: Consultancy; Jazz Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Novartis: Consultancy; Bayer: Consultancy; Daiichi Sankyo: Consultancy; Pfizer: Consultancy; Argenx: Consultancy. Cluzeau:Pfizer: Speakers Bureau; Sanofi: Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Menarini: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Germing:Celgene: Honoraria, Research Funding; Janssen: Honoraria; Novartis: Honoraria, Research Funding. Mukherjee:Takeda: Membership on an entity's Board of Directors or advisory committees; Takeda Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Projects in Knowledge: Honoraria; Pfizer: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; LEK Consulting: Consultancy, Honoraria; Bristol Myers Squib: Honoraria, Speakers Bureau; BioPharm Communications: Consultancy; Aplastic Anemia & MDS International Foundation in Joint Partnership with Cleveland Clinic Taussig Cancer Institute: Honoraria. Brunner:Celgene: Consultancy, Research Funding; Takeda: Research Funding; Novartis: Research Funding. Ritchie:NS Pharma: Research Funding; Incyte: Consultancy, Speakers Bureau; Novartis: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Astellas Pharma: Research Funding; Bristol-Myers Squibb: Research Funding; ARIAD Pharmaceuticals: Speakers Bureau; Pfizer: Consultancy, Research Funding; Celgene: Consultancy, Other: Travel, Accommodations, Expenses, Speakers Bureau. Podoltsev:Astex Pharmaceuticals: Research Funding; Celator: Research Funding; Astellas Pharma: Research Funding; Daiichi Sankyo: Research Funding; Sunesis Pharmaceuticals: Research Funding; Boehringer Ingelheim: Research Funding; CTI biopharma: Research Funding; Celgene: Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria. Gore:Celgene: Consultancy, Research Funding. Zeidan:Otsuka: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Takeda: Honoraria, Speakers Bureau; Agios: Consultancy, Honoraria.

Keywords: ruxolitinib; myeloproliferative neoplasm; blast phase; acute myeloid leukaemia; intensive chemotherapy