ALBERT

Description: Background: Unrelated cord blood transplantation (UCBT) after reduced intensity conditioning regimen (RIC) has extended the use of UCB in elderly and unfit patients without an HLA identical donor. KIR ligand incompatibility between donor and recipient might favor Natural Killer (NK) cell alloreactivity after UCBT in AML patients (Wilhemze et al, 2009), although contradictory results were reported (Brunstein et al, 2009). We previously reported the results of the biological NK cell reconstitution after RIC-UCBT in a French prospective phase II multicentric trial (Rio et al, 2015). We showed that NK cells generated from RIC-UCBT exhibited features of transient immaturity and stable activation, correlating with a high ability to produce IFN-γ and a quick restoration of the ability both to produce TNF-α and degranulate (Souchet et al, ASH 2013). The aim of the present study is to analyze the impact of KIR ligand incompatibilities and NK cell reconstitution on OS, DFS and TRM after RIC-UCBT in a prospective trial. Materials and methods: Seventy-six patients with a de novo or secondary AML in complete remission were enrolled in 23 centers from Oct. 2007 to Sept. 2009. Peripheral blood samples were collected during the first year following UCBT in order to realize an extensive prospective phenotypic and functional study of NK cells. DNA samples were also collected in recipient and cords blood to perform KIROTYPE and HLA-C allelic typing. NK biological data were available at M1 for 54 patients. The inhibitory Killer-Immunoglobin Receptors (KIR) KIR2DL1, and KIR2DL2/3 bind KIR ligand C2 and C1 respectively, resulting in inhibition of NK-cell mediated lysis. Recipients and UCB were classified into C1 or C2 family depending on their HLA-C typing (C1-C1, C1-C2 or C2-C2). Results: Among the 54 patients, 35 events occurred (relapse or TRM). Median EFS and OS were 13.2 and 18.3 months, respectively. Recipients C2-C2 had a significant worse EFS and OS than C1-C1 or C1-C2 (median EFS C2-C2=3.8 month vs 15.1 month for C1-x; p=0.002); median OS C2-C2 3.8 months vs 29.9 months for C1-x; HR=6.12, IC95% [2.069; 18.113], p=0.001). High intracellular staining of CD107a, reflecting the capacity of NK degranulation with HLA negative K562 target, correlated with better OS. CD107a expression was divided in 2 groups at median (=51%). Median OS of CD107 (0-50%) was 12.8 months vs 20.9 months for CD107a (51-66); p=0.029. Relapse risk was highly increased in recipients C2-C2 (HR=5.04 (IC 95% [1.23; 20.56], p=0.02). Low expression of CD16 (HR=0.97, IC95% [0.937; 0.999], p=0.043), high expression of HLA-DR (HR=1.08, IC95% [1.031; 1.123], p=8e-04) on NK cells, and recipients C2-C2 (HR=9.44, IC95% [1.311; 67.882], p=0.026) significantly increased the risk of TRM. The inhibitory KIR2DL1 receptor binds to C2 ligands. Of interest, KIR2DL1 was significantly decreased on C2-C2 recipients NK cells at M1, as compared to C1-x recipients NK cells. On the contrary, KIR2DL2/3 and KIR3DL1 restored promptly, suggesting a sequential expression of KIRs. As interaction between inhibitory KIRs and their ligands are essential for NK cells to become functional ("licensing" process), we can hypothesize that the weaker expression of KIR2DL1 on C2-C2 NK cells alters the licensing process, rendering the NK cells hypo-responsiveness. Conclusion: Recipient C2-C2 is correlated with a worse outcome (EFS, OS, relapse, TRM) after RIC-UCBT in a prospective trial for AML patients. Weak capacity of degranulation and low expression of CD16 are associated with worse OS and increased TRM, respectively. These features can reflect an alteration of the NK licensing process and might have impact on clinical outcome after UCBT. Disclosures No relevant conflicts of interest to declare.

Description: Background & aims The only curative treatment of CML to date, remains allogeneic stem cell transplantation (Allo-SCT) despite some observations of non-detectable disease recurrence after tyrosine kinase inhibitor (TKI) cessation. The scope of allogeneic stem cell transplant for chronic phase (CP-) CML remains debatable and it seems interesting to retrospectively analyse the settings of this procedure in such patients since the introduction of TKI within the therapeutic arsenal of this disease. Methods We retrospectively analysed the registry of the Francophone society of stem cell transplantation and cellular therapy (SFGM-TC) from 2002 to 2014, for patients being in CP at diagnosis and at transplant. All data were captured according to thefrench regulations and were collected after signed up informed consent for each patient. All patients were transplanted for different degrees of resistance or severe recurrent intolerance to TKI(s). We segmented the observation period into two parts: 2002-2006 (Imatinib era) and 2006-2014, once second generation TKI were available in our country (TKI2 era). All patients were in CP-CML at diagnosis and first chronic phase at transplant. Second transplants for the same patient were excluded from this analysis. Results From 2002 to 2014 the proportion of transplants for CML dramatically decreased form 7.1% to

Description: Mutations in the isocitrate dehydrogenase 1 (IDH1) gene are known driver mutations in acute myeloid leukemia (AML) and other cancer types. Patient outcomes in AML have remained poor, especially for patients above 60 years of age who typically do not tolerate high dose chemotherapy and stem cell transplantation, leading to cure rates below 20%. The development of novel targeted therapies for defined AML subtypes is urgently desired. Inhibitors of mutants of the closely related IDH2 gene as well as IDH1 have recently been described and show promising pre-clinical and early phase clinical activity. However, the specific molecular and functional effects of IDH1 inhibitors in AML, including in primary patients' cells, have not been reported yet. Here, we report the development of novel allosteric inhibitors of mutant IDH1 for differentiation therapy of acute myeloid leukemia. A high-throughput biochemical screen targeting an IDH1 heterodimer composed of R132H and WT IDH1 led to the identification of a tetrahydropyrazolopyridine series of inhibitors. Structural and biochemical analyses revealed that these novel compounds bind to an allosteric site that does not contact any of the mutant residues in the enzymes active site and inhibit enzymatic turnover. The enzyme complex locked in the catalytically inactive conformation inhibits the production of the oncometabolite 2-hydroxyglutarate (2-HG). In biochemical studies, we observed potent inhibition of several different clinically relevant R132 mutants in the presence or absence of the cofactor NADPH, accompanied by significant decrease in H3K9me2 levels. Allosteric inhibitor treatment of primary AML patients' cells with different clinically relevant R132 mutants of IDH1 ex vivo uniformly led to a decrease in intracellular 2-HG, abrogation of the myeloid differentiation block, increased cell death and induction of differentiation both at the level of leukemic blasts and immature stem-like cells. Allosteric inhibition of IDH1 also led to a decrease in blasts in an in vivo xenotransplantation model. At the molecular level, enhanced reduced representation bisulfite sequencing showed that treatment with allosteric IDH1 inhibitors led to a significant reversal of the DNA cytosine hypermethylation pattern induced by mutant IDH1, accompanied by gene expression changes of key sets of genes and pathways, including "Cell Cycle", "G1/S transition", "Cellular growth and proliferation", and "Cell death and survival". Taken together, our findings provide novel insight into the cellular and molecular effects of inhibition of mutant IDH1 in primary AML patients' cells. Furthermore, our study provides proof-of-concept for the molecular and biological activity of novel allosteric inhibitors for targeting of different mutant forms of IDH1 in leukemia, and opens new avenues for future investigations with these and other allosteric inhibitors for targeting mutant IDH1 in leukemia and other cancers. Disclosures Gao: GlaxoSmithKline: Employment. Pietrak:GlaxoSmithKline: Employment. Rendina:GlaxoSmithKline: Employment. Rominger:GlaxoSmithKline: Employment. Quinn:GlaxoSmithKline: Employment. Smallwood:GlaxoSmithKline: Employment. Wiggall:GlaxoSmithKline: Employment. Reif:GlaxoSmithKline: Employment. Schmidt:GlaxoSmithKline: Employment. Qi:GlaxoSmithKline: Employment. Zhao:GlaxoSmithKline: Employment. Joberty:GlaxoSmithKline: Employment. Faelth-Savitski:GlaxoSmithKline: Employment. Bantscheff:GlaxoSmithKline: Employment. Drewes:GlaxoSmithKline: Employment. Duraiswami:GlaxoSmithKline: Employment. Brady:GlaxoSmithKline: Employment. Concha:GlaxoSmithKline: Employment. Adams:GlaxoSmithKline: Employment. Schwartz:GlaxoSmithKline: Employment. McCabe:GlaxoSmithKline: Employment.

Description: Key Points Next-generation sequencing broadens the spectrum of germ line mutations in a cohort of patients with likely-inherited BMF. Salient clinical features and distinct natural histories are consistently found in SAMD9L and SAMD9, MECOM/EVI1, and ERCC6L2 disorders.

Description: Background: Mutations of MAP2K1, which encodes MEK1, have been identified in up to half of patients with variant Hairy Cell Leukemia (vHCL).[Waterfall et al., Nat Gen 2014, Mason et al., Leukemia & Lymphoma 2016], and have been associated with vHCL with IGHV4-34 gene usage, which This form of HCL tends to have a worse prognosis than classic HCL or wild type vHCL (Arons et al., Blood 2009), with inferior responses to chemotherapy and shorter durations of remission. Trametinib, an oral inhibitor of MEK1 and MEK2, is FDA approved for treatment of patients with BRAF p.V600E mutant melanoma. We hypothesized that this MEK inhibitor would have activity in MAP2K1 mutant vHCL. Case Report: The patient is a 52 year old man with a history of CD25+, BRAF wildtype, IGHV4-34 usage vHCL diagnosed in 2005. His previous treatments included cladribine, BL22, pentostatin/rituximab, splenectomy, single agent rituximab, ibrutinib, bendamustine/rituximab, and allogeneic transplantation from a matched unrelated donor. The patient experienced disease relapse day +350 post transplant when he developed skin nodules as well as a generalized skin rash. The skin rash appeared clinically consistent with acute GVHD. However, when biopsies of both the skin nodules and skin rash were performed he was found to have relapsed vHCL. He was consented for paired tumor and germline next generation sequencing with a 25-gene amplicon panel which revealed a somatic MAP2K1 K57N mutation that has been shown to constitutively activate MEK [Marks et al., Cancer Res 2008]. As the patient had exhausted the majority of available treatment options, he was prescribed trametinib 2 mg po daily (commercial supply, according to approved melanoma dosing). Within a week of therapy initiation his skin nodules were markedly diminished in size and his generalized rash had resolved. He did develop a new acneiform rash over his face consistent with drug toxicity. This was managed with topical agents with improvement and did not require a dose reduction. Disease restaging following cycle 2 of therapy showed near complete resolution of skin nodules, with disappearance of visible skin rash. Repeat bone marrow biopsy showed unchanged hairy cell index. Skin biopsies were repeated and phospho-ERK (T202/Y204) staining of skin biopsies pre- and post-trametinib were performed (Figure 1). This showed diminished lymphocyte involvement on H&E staining with a decrease in p-ERK expression on immunostaining, indicative of decreased signaling downstream of MEK and consistent with on target trametinib effects. As of this writing, the patient has remained on trametinib for 12 weeks with no recurrence of leukemia cutis rash. Discussion: MEK inhibition with the oral MEKi trametinib is a well tolerated therapy with clinical activity in MAP2K1 mutant vHCL. Additional studies of this agent are warranted. Optimal dose and duration of therapy will need to be explored in prospective clinical trials. Figure 1 Skin biopsies pre- and post-trametinib. (A)(C) H&E staining shows diminished lymphocyte involvement. (B)(D) PhosphoERK immunostaining shows decrease of phosphoERK expression. Bar = 500 μm Figure 1. Skin biopsies pre- and post-trametinib. (A)(C) H&E staining shows diminished lymphocyte involvement. (B)(D) PhosphoERK immunostaining shows decrease of phosphoERK expression. Bar = 500 μm Disclosures Andritsos: Hairy Cell Leukemia Foundation: Research Funding. Anghelina:Hairy Cell Leukemia Foundation: Research Funding. Lozanski:Boehringer Ingelheim: Research Funding; Beckman Coulter: Research Funding; Genentech: Research Funding; Stemline Therapeutics Inc.: Research Funding. Jones:Pharmacyclics, LLC, an AbbVie Company: 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, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Description: Ibrutinib is a promising targeted therapy for chronic lymphocytic leukemia (CLL). However, a small subset of patients progress on ibrutinib either through progressive CLL or Richter's transformation. Patients responding to ibrutinib and then progressing with Richter's transformation do so most commonly within the first 2 years of treatment and have an extremely poor prognosis. Identifying biomarkers associated with this transformation is of utmost importance. Near-tetraploidy (4 copies of most chromosomes within a cell) has been reported in various lymphomas; however, its incidence in CLL has not been described. We investigated the prevalence of near-tetraploidy in CLL patients prior to starting ibrutinib and identified it as a pre-treatment biomarker for Richter's transformation. We examined near-tetraploidy in a large series of CLL patients enrolled across four ibrutinib clinical trials at the Ohio State University, for which extensive correlative studies and follow up data are available (previously described by Maddocks et al., JAMA Oncol, 2015). We identified this abnormality in 9 of 300 patients (3.0%, 95% CI: 1.4-5.6) in blood or bone marrow samples taken prior to starting therapy. Near-tetraploidy was detected by the presence of four signals with four or more fluorescence in situ hybridization (FISH) probes and confirmed in the metaphase karyotype of each patient in at least one cell. Near-tetraploidy was associated with aggressive disease characteristics including: Rai stage 3/4 (p=0.03), deletion 17p (p=0.03), and complex karyotype (p=0.01), as well as trisomy 12 (p=0.05). With a median follow-up time of 40.5 months, in patients positive with near-tetraploidy, one patient (11%) progressed with CLL on ibrutinib, six patients (67%) progressed with Richter's transformation, and two patients (22%) were still on treatment. Cumulative incidence of Richter's transformation was significantly higher in patients with near-tetraploidy (Figure; p

Description: Key Points Cytoreduction with obinutuzumab and ibrutinib followed by the addition of venetoclax has acceptable safety with no tumor lysis syndrome. This combination has preliminary activity including complete remissions with undetectable residual disease in relapsed or refractory CLL.

Description: Hematopoietic Stem cell Transplantation (HSCT) is the definitive treatment for bone marrow failure in diskeratosis congenita (DC). Organ dysfunction (mainly lung and gastrointestinal tract) are often part of the disease and may be a limiting factor for or may affect the final outcome of HSCT. Scarce data or relatively small cohort studies are available in current literature on outcome of HSCT in this disease. We analyzed the outcome of 87 patients diagnosed with DC reported in the data base of the European Society for Blood an Bone Marrow Transplantation (EBMT) who underwent HSCT from 1979 to 2014. In particular we analyzed data on type of HSCT, characteristic of donors, source of cells, incidence of acute and chronic GvHD. Males were 76%. Median age at diagnosis of DC was 5.7 years (0-33 yrs), median age at HSCT was 11.2 years (range 0.56-41 yrs). Median time from diagnosis to HSCT was 19 months (0.62-304 mo). The cell source was bone marrow (BM) in 67%, peripheral blood (PB) in 22% and cord blood (CB) 11%. Twenty six percent of patients were engrafted from a matched related and 53% from a matched unrelated donor. Twenty one percent of subjects were engrafted from a mismatched (both related and unrelated) HSCT. Engraftment was documented in 95% of subjects: 4 % had primary graft failure and 10% lost the graft. Overall 35 patients (40%) died, and 52 were alive (60%) at last follow-up. Causes of death were: infections (43%), multi-organ failure (26%), rejection/oss of graft (14%), GvDH (8.5%) undefined (8.5%). In 32% of cases death was related to transplant. Lung injury was present in 17% of subjects who died. Acute GVDH (mainly grade 2-4) and chronic GvHD occurred in 39% and 30% of cases. Five year OS was 60 %. OS was not significantly different by calendar period (before and after year 2000: 50% vs 67% respectively, p=0.424), by age at transplant (below and above age of 12 years: 64% vs 55% respectively ; p= 0.564) and by source of cells (marrow 60%, cord blood 68%, and peripheral cells 46%; p= 0.687). Conversely, OS in HSCT from mismatched donor was inferior to that of transplants from matched donor (38% vs 65% respectively; p= 0.045). The use of radiotherapy or busulfan (any dose) in the conditioning vs other regimens did not impact on 5 y-OS ( 58% vs 62% respectively; p=0.898). HSCT from HLA matched donor can be considered a treatment option in DC. Transplant related mortality looks rater high. Multi organ failure and lung injury are amongst the main causes of death thus pointing to pre-transplant organ status as important determinant of HSCT outcome. Disclosures Dufour: Pfizer: Consultancy.

Description: Background: Umbilical cord blood transplantation (UCBT) is a potentially curative therapy acute leukemia (AL) patients. Transplantation benefit must be balanced against risks, such as transplant related mortality and relapse. The complex nature of hematopoietic stem cell transplantation data (HCT), rich in interactions and possibly nonlinear associations, has motivated us to apply machine learning (ML) for predictive modeling. ML is a field of artificial intelligence and is part of the data mining approach for data analysis. Our group has recently reported on a ML based prediction model for short term HCT outcomes (Shouval R et al; JCO 2015). Using a ML algorithm, the perspective of the current study was prediction of leukemia free survival (LFS) at 2 years after an UCBT, while exploring variables' importance and interactions. Patients & Methods: A cohort of 3,149 UCBT were analyzed. Inclusion criteria encompassed patients at all ages, undergoing an UCBT (single/double unit) in EBMT centers from the year 2004 to 2014, for AL, in all disease status. All conditioning and graft versus host disease prophylaxis regiments were included. A total of 24 variables were considered, including the number of total nucleated cell dose (TNC), donor and recipients HLA typing, as well as recipient, disease and transplant characteristics. The Random Survival Forest (RSF) ML algorithm was applied for model construction and data exploration. RSF is known to be adaptive to data, is able to automatically recover nonlinear effects and complex interactions among variables, and yields nonparametric prediction over test data. The analysis pipeline consisted of prediction model development, assessment of variable importance by their minimal depth from the tree trunk, and exploration of the top ranking variable with dependence plots. The latter promotes understanding of non-trivial associations between variables and outcomes. Results : The 2 years LFS was 49%, with a median follow up of 30 months. A RSF model of 1000 trees was developed, with each tree constructed on a bootstrap sample from the original cohort. A prediction error of 36.0% was calculated. The 10 most predictive variables (in ascending order) were disease status, age, TNC harvested and infused, recipient CMV serostatus, interval from diagnosis to UCBT, transplant year, previous autologous transplant, and use of anti-thymocyte globulin (ATG). Selected findings from exploration of variables-outcome relationship with dependence plots included a varying effect of TNCs in specific subpopulations. Increasing the number of infused TNCs had a positive effect on predicted LFS in patients receiving HLA mismatched (2 or more HLA mismatch) (figure) or single unit CB grafts, and patients in earlier disease status or older age. ATG administration was associated with worse LFS, whether unadjusted or adjusted to all other variables. However, there was an additional negative effect in advanced disease status patients, recipients of HLA mismatched or single CB units grafts, and older patients. Patients in 1st complete remission (CR) had higher predicted LFS as compared to those in 2nd CR. However, in patients receiving a HLA mismatched or a double CB graft, the difference in LFS between CR1 and CR2 was attenuated. Younger age had a favorable impact in early disease status, but lost its positive effect in advanced disease. Conclusions: A prediction model for LFS 2 years post UBCT was developed using the RSF ML algorithm. Variables were ranked according to their predictive contribution. Disease status, age, and TNC count were found to be the most important factors. Dependence plots revealed interactions and nonlinear associations between variables and the outcome, such as the effect of cell dose on HLA disparity. Apart from the study's clinical findings, it carries a methodological significance. A novel ML approach for prediction, variable selection and data exploration, accounting for long term time to event outcomes, has proved useful in the field of HCT. Figure 1. Variable marginal dependence coplot of predicted LFS at 2 years against TNC, conditional on HLA matching. Individual cases are marked with blue circles (alive or censored) and red `x's (event). Linear smooth (a linear extrapolation of the prediction function), with shaded 95% confidence band, indicates trends of variable dependence. Figure 1. Variable marginal dependence coplot of predicted LFS at 2 years against TNC, conditional on HLA matching. Individual cases are marked with blue circles (alive or censored) and red `x's (event). Linear smooth (a linear extrapolation of the prediction function), with shaded 95% confidence band, indicates trends of variable dependence. Disclosures Mohty: Janssen: Honoraria; Celgene: Honoraria. Sanz:JANSSEN CILAG: Honoraria, Research Funding, Speakers Bureau. Bader:Neovii: Other: Institutional grants; Medac: Other: Institutional grants; Riemser: Other: Institutional grants; Amgen: Consultancy; Novartis: Consultancy; Jazz Pharmaceuticals: Consultancy.

Description: Introduction: The Bruton's Tyrosine Kinase (BTK) inhibitor ibrutinib (IB) is a standard therapy for previously untreated CLL patients. While therapy is currently indicated only for patients with progressive, symptomatic disease, the introduction of targeted therapies in CLL has re-opened the question of whether asymptomatic high risk patients would benefit from early intervention. As well, even in early stages CLL is associated with profound cellular, humoral and innate immune suppression and patients with CLL respond poorly to routine vaccinations. IB has been shown to reverse disease mediated immune dysfunction partly through Th1 skewing. We undertook a phase 2 study of IB in asymptomatic high risk CLL patients who did not otherwise require therapy to evaluate: 1) the safety and efficacy of 2 years of IB in this clinical setting and 2) ability of IB to improve the efficacy of routine vaccines. Methods: This is a single-stage phase II study of IB in previously untreated asymptomatic, genetically high-risk patients with CLL, who did not meet IWCLL treatment criteria. High risk genomics were defined as del(11)(q22.3), del(17)(p13.1), unmutated IGHV, and/or complex karyotype (≥3 cytogenetic abnormalities). Patients were randomized to receive IB 420mg PO daily either concurrent with the pneumococcal (PCV13), influenza and TdaP vaccines (Arm A) or following vaccination (Arm B) for a total of 27 cycles (2 years). The primary objective of the study was to determine the safety and 2-year progression-free survival (PFS) of asymptomatic, high-risk CLL patients treated with IB. Secondary objectives include determination of safety and immune responses to vaccines in relation to IB administration, development of resistance, and quality-of-life (QOL). QOL measures assessed general QOL (SF-12, EORTC), anxiety (GAD-7) and depression (PHQ-9). Results: Forty-four patients (pts; 21 in Arm A, 23 in Arm B) were enrolled from 1/2016 to 6/2017, with a median age of 58 (range 35-82). Sixty-six percent of pts were male and all were high-risk: 91% with unmutated IGHV, 14% with del(17)(p13.1), 34% with del(11)(q22.3), and 24% with complex karyotype (≥ 3 abnormalities). Median follow-up is 2.6 years (range: 0.2-3.2). Excluding 2 patients in Arm B who progressed prior to receipt of IB, 2-year PFS was 92%. From a landmark of 2-years and including 33 patients who reached this point and discontinued IB, 6-month PFS was 87% (95% CI: 69-95%; Figure 1). Of 9 pts who progressed after IB discontinuation, 3 have not required further treatment, 5 restarted IB or acalabrutinib, and 1 started venetoclax/rituximab, and all responded. For PCV13, in Arm A, 15/16 patients showed a significant increase in antibody titer 2 cycles following vaccination, but response disappeared by cycle 12. In Arm B, 3/13 patients had an increase in antibody titer, with no increase following second vaccination. For influenza, patients in Arm B showed a significant response to influenza A vaccination, while patients in both arms responded to influenza B vaccination. IB was generally well tolerated, and only one pt discontinued treatment due to toxicity (atrial fibrillation). Grade 3+ toxicities that occurred in 〉2% of patients included anemia (7%), atrial fibrillation (11%), dental caries (7%), hyperglycemia (7%), hypertension (43%), and neutropenia (7%). At baseline, patients' reports of physical health-related (M=48.52, SD=7.96) and mental health-related quality of life (M=52.20, SD=8.57) similar to U.S population norms, along with moderately high global health (M=78.49 of 100, SD = 20.51). Additionally, patients' anxiety (M=3.56, SD=4.71) and depressive symptom reports (M=3.65, SD=4.46) were in the "none/mild" range. There was no significant change in the latter measure from baseline to 12 months (p〉0.25), excepting anxiety which slightly decreased (M=1.31, SD=2.33; F(3,44)=5.94, p