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Preclinical research of myelodysplastic syndromes (MDSs) is hampered by a lack of feasible disease models. Previously, we have established a robust patient-derived xenograft (PDX) model for MDS. Here we demonstrate for the first time that this model is applicable as a preclinical platform to address pending clinical questions by interrogating the efficacy and safety of the thrombopoietin receptor agonist eltrombopag. Our preclinical study included n = 49 xenografts generated from n = 9 MDS patient samples. Substance efficacy was evidenced by FACS-based human platelet quantification and clonal bone marrow evolution was reconstructed by serial whole-exome sequencing of the PDX samples. In contrast to clinical trials in humans, this experimental setup allowed vehicle- and replicate-controlled analyses on a patient–individual level deciphering substance-specific effects from natural disease progression. We found that eltrombopag effectively stimulated thrombopoiesis in MDS PDX without adversely affecting the patients’ clonal composition. In conclusion, our MDS PDX model is a useful tool for testing new therapeutic concepts in MDS preceding clinical trials.

Myelodysplastic syndrome (MDS) with isolated deletion of chromosome 5q (MDS del5q) is a distinct subtype of MDS with quite favorable prognosis and excellent response to treatment with lenalidomide. Still, a relevant percentage of patients do not respond to lenalidomide and even experience progression to acute myeloid leukemia (AML). In this study, we aimed to investigate whether global DNA methylation patterns could predict response to lenalidomide. Genome-wide DNA methylation analysis using Illumina 450k methylation arrays was performed on n=51 patients with MDS del5q who were uniformly treated with lenalidomide in a prospective multicenter trial of the German MDS study group. To study potential direct effects of lenalidomide on DNA methylation, 17 paired samples pre- and post-treatment were analyzed. Our results revealed no relevant effect of lenalidomide on methylation status. Furthermore, methylation patterns prior to therapy could not predict lenalidomide response. However, methylation clustering identified a group of patients with a trend towards inferior overall survival. These patients showed hypermethylation of several interesting target genes, including genes of relevant signaling pathways, potentially indicating the evaluation of novel therapeutic targets. Supplementary Information The online version contains supplementary material available at 10.1007/s00277-021-04492-1.

Although acute promyelocytic leukemia (APL) has evolved to the AML entity with the best prognosis, typical 'early death' (ED) events still account for mortality rates of ∼20% in population-based studies. To investigate this poorly understood issue we performed whole transcriptome analysis of

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.

The hypomethylating agent 5-azacytidine (5-Aza) is a standard-of-care for patients with higher-risk myelodysplastic syndromes (MDS). Although an initial response is induced in approximately 50% of 5-Aza treated patients, subsequent relapse is almost certain. Recently, inhibitors of anti-apoptotic BCL-2 protein family members have shown therapeutic potential in acute myeloid leukemia (AML) and higher-risk MDS. Alvocidib (Alv), a CDK9 inhibitor and indirect transcriptional repressor of the anti-apoptotic factor MCL-1, has shown anti-leukemic effects in a phase 1 study of patients with AML (Lee DJ et al, Expert Opin Investig Drugs 2019; Zeidner JF et al, Leuk Res 2015). A phase 1b/2 study with Alv and 5-Aza or decitabine in higher-risk patients with MDS was recently completed (NCT03593915); however, biomarkers for response to the Alv and 5-Aza combination are not well characterized. To identify potential biomarkers of response, we performed a comprehensive in vitro assessment of Alv and 5-Aza combination using a clinically well-characterized cohort of n=45 higher-risk patients with MDS and n=11 healthy controls (HC). CD34+ cells were purified from bone marrow (BM) aspirates using positive selection with MACS beads. CD34+ cells of HC were obtained from femur head replacement surgery bone specimens. After 4 days of expansion in SFEM II medium containing StemSpan Myeloid Expansion Supplement, cells were treated with 5-Aza for 48h, Alv for 24h or their combination (5-Aza for 48h followed by Alv for 24h). Cell viability was determined using CellTiter-Glo (CTG) and Annexin-V apoptosis assays. MCL-1 dependency of MDS samples was assessed using MS1 peptide-based assay. Recurrent myeloid neoplasia mutations in 67 genes were assessed in BM mononuclear cells using NGS panel deep sequencing. The combination of 5-Aza+Alv had an additive cytotoxic effect on CD34+ MDS cells in CTG assay (median cell viability = 74%, 73.8% and 55% for 5-Aza, Alv and combination respectively, p Citation Format: Vladimir Ryabov, Nanni Schmitt, Qingyu Xu, Alexander Streuer, Johann-Christoph Jann, Alina Wein, Eva Altrock, Verena Nowak, Nadine Weimer, Julia Obländer, Iris Palme, Ahmed Jawhar, Ali Darwich, Patrick Wuchter, Christel Weiss, Georgia Metzgeroth, Jason M. Foulks, Laurenz Steiner, Mohamad Jawhar, Wolf-Karsten Hofmann, Daniel Nowak. Mutations in the ASXL1 and ZRSR2 genes are associated with the response to the combination of alvocidib and 5-azacytidine in higher-risk myelodysplastic syndromes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6257.

In low risk MDS, increased apoptosis of erythroid progenitors mediated via CD95 (Fas) activation has been described to result in peripheral cytopenia. Blockade of the CD95 system can improve erythropoiesis in MDS. Asunercept (APG101) is a fusion protein consisting of the extracellular domain of human CD95 and the Fc domain of human IgG1 blocking the interaction between CD95 and its ligand. Here we report on results from a phase I study in 20 transfusion-dependent low and intermediate risk MDS patients treated with intravenous asunercept (EudraCT 2012-003027-37). Primary objectives were safety and tolerability as well as pharmacodynamic effects. Secondary objectives were hematologic improvement, incidence and time to leukemic progression as well as overall survival. Frequency and severity of adverse events were in range of what could be expected in a patient cohort comprising of elderly MDS patients. Two patients experienced a serious adverse event with a suspected relationship to asunercept. The incidence of disease progression was low. In the 20 patients a decrease of the transfusion need from a mean of 10,8 (±5,1) pRBCs during the 12 weeks treatment phase to a mean of 10,0 (±4,2) pRBCs at the end of the study was observed. In conclusion, asunercept was well tolerated and showed efficacy in transfusion-dependent low and intermediate risk MDS patients. Further clinical investigation is warranted, particularly in combination with erythropoiesis stimulating agents (ESAs).

Hypomethylating therapy with 5-azacytidine (5-Aza) is a standard-of-care for patients with higher-risk myelodysplastic syndromes (MDS). Response is induced in approximately 50% of 5-Aza treated patients. However, despite robust efficacy in responders, relapse is almost certain. Recently, inhibitors of anti-apoptotic BCL-2 protein family members have shown potent activity against AML and higher-risk MDS in combination with 5-Aza. Alvocidib (Alv), a cyclin-dependent kinase 9 inhibitor and indirect transcriptional repressor of the anti-apoptotic BCL-2 family member MCL-1, has shown anti-leukemic effects in combination with 5-Aza in a phase 1 study of AML (Lee DJ et al, Expert Opin Investig Drugs 2019; Zeidner JF et al, Leuk Res 2015). Additionally, Alv has entered a phase 1b/2 study in patients with higher-risk MDS (NCT03593915). In order to possibly identify biomarkers of response, we performed a comprehensive pre-clinical in vitro assessment of Alv combined with 5-Aza using a clinically well-characterized cohort of n=40 MDS (high risk) patients and n=11 healthy controls. CD34+ HSCs were purified from bone marrow (BM) aspirates using positive selection with MACS microbeads. CD34+ cells of healthy controls were obtained from femur head replacement surgery bone specimens. Hematopoietic stem cells (HSCs) were expanded for four days in StemSpan SFEM II medium containing StemSpan Myeloid Expansion Supplement (Stem Cell Technologies) and treated with 5-Aza for 48h, Alv for 24h or their sequential combination (5-Aza for 48h followed by Alv for 24h). Cell viability was determined using CellTiter-Glo and Annexin-V apoptosis assays. MDS recurrent mutations in BM mononuclear cells were assessed using myeloid NGS panel deep sequencing containing 67 genes. The combination of 5-Aza+Alv showed an additive cytotoxic effect on CD34+ MDS cells in CellTiter- Glo cell viability assays (median cell viability = 74%, 73.8% and 55% for 5-Aza, Alv and combination respectively, p Disclosures Schmitt: Affimed GmbH: Research Funding. Jawhar: Celgene: Other: Travel support; Takeda: Honoraria, Other: Travel support; Stemline: Consultancy, Honoraria; Blueprint Medicines: Honoraria; Novartis: Consultancy, Honoraria, Other: Travel support, Speakers Bureau. Foulks: Sumitomo Dainippon Pharma Oncology: Patents & Royalties: WO2021102343A1; Sumitomo Dainippon Pharma Oncology: Patents & Royalties: CA3103995A1; Sumitomo Dainippon Pharma Oncology: Patents & Royalties: US11040038B2. Hofmann: Amgen: Honoraria; BMS: Honoraria; Novartis: Honoraria. Nowak: Celgene: Honoraria; Takeda: Honoraria; Affimed: Research Funding; Pharmaxis: Current holder of individual stocks in a privately-held company, Research Funding; AbbVie: Other: Investigator on funded clinical trial; Tolero Pharma, Pharmaxis, Apogenix: Research Funding.

Introduction: Patients (pts) with higher-risk myelodysplastic syndromes (MDS) are typically treated with azacitidine (Aza). Venetoclax (Ven) is a selective, potent, oral BCL-2 inhibitor that has demonstrated synergy with Aza in preclinical studies of myeloid malignancies. Higher-risk MDS is associated with mutations in genes involved in RNA splicing, epigenetic regulation, transcription, and cellular signaling. Assessing the dynamics of genetic variants during treatment of higher-risk MDS enables understanding of the molecular determinants of response. This phase 1b study (NCT02942290) evaluates Ven + Aza for treatment-naïve higher-risk MDS, and we report efficacy among mutationally defined subgroups as well as the depth of molecular response. Methods: Pts (≥18 years) with higher-risk MDS enrolled in the study had International Prognostic Scoring System intermediate-2 or high-risk MDS, bone marrow (BM) blasts Molecular responses were quantified by mutation analysis of baseline and serial BM aspirate (BMA) or peripheral blood (PB) samples collected at protocol-specified time points. Mutations were identified in BMA using Archer VariantPlex Myeloid 75-gene panel [limit of detection (LOD) 5%; time points: pre-treatment (n=43), on-treatment (n=32), and treatment completion visit (TCV) (n=25)] or TruSight Myeloid 54-gene Sequencing Panel in PB [LOD 2%; time points: pre-treatment (n=21), on-treatment (n=19), and TCV (n=8)] to assess molecular dynamics during Ven + Aza treatment. Molecular responses were only compared within the same tissue type. Results: At the Dec 15, 2020 cutoff, 78 pts had received Ven+Aza, including 51 who received Ven at the RP2D of 400 mg x 14 d, with median follow up time of 23 mos (range 0.1-44.2). Median age was 70 years (range 26-87); 72% male; and 91% had excess BM blasts (>5 to ≤10%, n=21; >10 to ≤20%, n=49; >20%, n=1). For the entire population, mORR was 80% (CR 40% and mCR 40%; no PR). 42% with mCR also had hematologic improvement [HI]. Screening mutational profiling was performed on 46/51 pts who received the RP2D of Ven + Aza. The most common mutations were TP53 (26%), ASXL1 (24%), U2AF1 (17%), and RUNX1 (15%), consistent with a higher-risk MDS population. Clinical responses (CR + mCR) were observed across the mutational spectrum, including in pts with poor prognostic mutations in TP53 (83%), ASXL1 (82%), and RUNX1 (71%). Sixty-four pts treated with Ven + Aza (all Ven dosing cohorts) had paired BMA or PB pre-treatment and on-treatment and/or end of study samples available for serial analysis at the Dec 15, 2020 data cutoff. Ven + Aza resulted in robust and rapid molecular responses across the mutational spectrum. Pts who achieved CR at the time of serial sample acquisition had more significant reduction of variant allele frequencies (VAFs) (n=18 pts, mean VAF pre-treatment = 38.3; mean VAF at CR = 11.8) compared to pts who achieved stable disease or HI (n=11 pts, mean VAF pre-treatment = 29.8; mean VAF at SD or HI = 24.0) or progressive disease (n=10 pts, mean VAF pre-treatment = 27.4; mean VAF at PD = 26.9). Reductions of VAFs below the LOD were observed across the mutational spectrum, including in genes that are considered poor prognostic in higher-risk MDS (e.g., TP53, ASXL1 and RUNX1), demonstrating the broad molecular activity of Ven + Aza (Figure). Finally, molecular responses were observed quickly, with VAF reductions below the LOD observed as early as end of Cycle 1, consistent with the mechanism of action of Ven directly activating the mitochondrial apoptotic pathway in cells. Conclusions: Pts with higher-risk MDS treated with Ven + Aza had rapid, durable responses and high remission rates. Pts across key mutational profiles achieved meaningful clinical and molecular responses, supporting an all-comers approach. Updated data will be presented, which will provide more follow up time and durability of responses among mutational subsets. Figure 1 Figure 1. Disclosures Garcia: Genentech: Research Funding; Takeda: 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; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Research Funding; Prelude: Research Funding; Pfizer: Research Funding. Wei: Novartis, Celgene, AbbVie, Servier, AstraZeneca, and Amgen: Research Funding; Novartis, Janssen, Amgen, Roche, Pfizer, Abbvie, Servier, BMS, Macrogenics, Agios, Gilead: Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria. Jacoby: Abbvie: Research Funding; Jazz: Research Funding. Fong: Amgen, BMS: Speakers Bureau; AbbVie, Amgen, Novartis, Pfizer, Astellas: Honoraria; Amgen: Research Funding. Borate: Jazz Pharma: Research Funding; Blueprint Medicine: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Pfizer: 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; Genentech: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rampal: Membership on an entity's Board of Directors or advisory committees; Galecto, Inc.: Consultancy; Promedior: Consultancy. Cunningham: AbbVie, Amgen, Astex, Celgene, Janssen, Novartis, Principia Biopharma, Rigel: Research Funding. Odenike: Celgene, Incyte, AstraZeneca, Astex, NS Pharma, AbbVie, Gilead, Janssen, Oncotherapy, Agios, CTI/Baxalta, Aprea: Research Funding; AbbVie, Celgene, Impact Biomedicines, Novartis, Taiho Oncology, Takeda: Consultancy. Jurcic: AbbVie, BMS/Celgene, Novartis: Consultancy; AbbVie, Arog Pharmaceuticals, Astellas, BMS/Celgene, Forma Therapeutics, Genentech, Gilead Sciences, PTC Therapeutics, Syros Pharmaceuticals: Research Funding. Nowak: Pharmaxis: Current holder of individual stocks in a privately-held company, Research Funding; AbbVie: Other: Investigator on funded clinical trial; Affimed: Research Funding; Tolero Pharma, Pharmaxis, Apogenix: Research Funding; Celgene: Honoraria; Takeda: Honoraria. Platzbecker: Janssen: Honoraria; Celgene/BMS: Honoraria; Geron: Honoraria; AbbVie: Honoraria; Novartis: Honoraria; Takeda: Honoraria. Dunshee: Genentech/Roche: Current Employment, Current equity holder in publicly-traded company. Zhou: AbbVie: Current Employment, Current holder of stock options in a privately-held company. Hoffman: AbbVie: Current Employment, Current holder of stock options in a privately-held company. Sun: AbbVie: Current Employment. Popovic: AbbVie: Current Employment, Current equity holder in publicly-traded company. Ainsworth: AbbVie: Current Employment, Current holder of stock options in a privately-held company. Naqvi: Genentech/Roche: Current Employment, Current holder of stock options in a privately-held company. Kye: AbbVie: Current Employment, Other: May hold equity. Hogdal: AbbVie: Current Employment, Current holder of stock options in a privately-held company.

Background: Venetoclax (Ven), a selective oral BCL-2 inhibitor, demonstrated synergy with azacitidine (Aza) in patients with higher-risk myelodysplastic syndromes (HR-MDS). Objective: We report updated safety and efficacy in an ongoing phase 1b study (NCT02942290) evaluating Ven+Aza for treatment-naive HR-MDS patients. Methods: Patients (≥18yrs) with International Prognostic Scoring System (IPSS) intermediate-2 or high-risk MDS, bone marrow (BM) blasts Main Outcomes Measures: Primary objectives were assessing Ven+Aza safety profile and establishing RP2D. Key secondary objectives included overall response rate (ORR) and overall survival (OS). Results: At data cutoff (Dec. 15, 2020), 78 patients received Ven+Aza (51 at RP2D 400 mg x 14 d), with median follow-up time of 23 mos. Median age was 70 yrs; 72% male; 90% had excess BM blasts (>5 to 10%, n=21; >10 to 20%, n=49). Grade 3/4 neutropenia (59%) or thrombocytopenia (33%) were present at baseline. All patients experienced ≥1 treatment-emergent adverse event (TEAE), the most common being neutropenia (83%), nausea (55%), and constipation (54%); 96% experienced grade 3/4 TEAEs, with neutropenia (82%), febrile neutropenia (49%), and thrombocytopenia (42%) being most common. Neutropenia (49%), including febrile neutropenia (45%), was the most common serious TEAE. The 30-d mortality rate after first dose was 1%. Intention-to-treat ORR was 80%, including complete remission (CR,40%) and marrow CR (mCR, 40%); 42% mCR had hematologic improvement; no partial remissions recorded. For 31 CR patients, median time to CR and median duration of response was 2.6 and 13.8 mos (95% CI 8.9,–), respectively. Post-baseline transfusion independence rate (defined as no transfusion ≥8 weeks), for patients transfusion-dependent for RBC and/or platelets at baseline, was 46.5%. Median OS was 28.2 mos (95% CI 17.7, –). Median OS for 31 patients achieving CR was 28.6 mos (95% CI 27.5, –). Twenty-three percent moved on to post-study allogeneic HSCT (including BM and peripheral blood stem cells). Conclusions: The combination of Ven+Aza was associated with rapid and durable response, promising efficacy, including remission rates and OS, and an acceptable safety profile for patients with HR-MDS. Additional correlation with disease risk features, including TP53 mutations, will be presented.

// Elke Burgermeister 1,* , Patrick Hode 1,* , Johannes Betge 1 , Tobias Gutting 1 , Andreas Merkel 1 , Wen Wu 1 , Marc Tanzer 2 , Maximilian Mossner 3 , Daniel Nowak 3 , Julia Magdeburg 4 , Felix Ruckert 4 , Carsten Sticht 5 , Katja Breitkopf-Heinlein 1 , Nadine Schulte 1 , Nicolai Hartel 1 , Sebastian Belle 1 , Stefan Post 4 , Timo Gaiser 6 , Barbara Ingold Heppner 7 , Hans-Michael Behrens 8 , Christoph Rocken 8 and Matthias P.A. Ebert 1 1 Department of Medicine II, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany 2 Department of Medicine II, Klinikum rechts der Isar, Technische Universitat Munchen, Munich, Germany 3 Department of Medicine III, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany 4 Department of Surgery, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany 5 Center for Medical Research (ZMF), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany 6 Institute of Pathology, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany 7 Institute of Pathology, University Hospital Charite, Berlin, Germany 8 Institute of Pathology, Christian-Albrechts University, Kiel, Germany * These authors have contributed equally to this work Correspondence to: Matthias P.A. Ebert, email: // Keywords : TUSC3, colorectal cancer, prognosis, glycosylation, growth factor receptor Received : March 14, 2017 Accepted : August 23, 2017 Published : September 15, 2017 Abstract Colorectal cancer (CRC) is a biologically and clinically heterogeneous disease. Even though many recurrent genomic alterations have been identified that may characterize distinct subgroups, their biological impact and clinical significance as prognostic indicators remain to be defined. The tumor suppressor candidate-3 ( TUSC3/N33 ) locates to a genomic region frequently deleted or silenced in cancers. TUSC3 is a subunit of the oligosaccharyltransferase (OST) complex at the endoplasmic reticulum (ER) which catalyzes bulk N-glycosylation of membrane and secretory proteins. However, the consequences of TUSC3 loss are largely unknown. Thus, the aim of the study was to characterize the functional and clinical relevance of TUSC3 expression in CRC patients’ tissues ( n =306 cases) and cell lines. TUSC3 mRNA expression was silenced by promoter methylation in 85 % of benign adenomas ( n =46 cases) and 35 % of CRCs ( n =74 cases). Epidermal growth factor receptor (EGFR) was selected as one exemplary ER-derived target protein of TUSC3-mediated posttranslational modification. We found that TUSC3 inhibited EGFR-signaling and promoted apoptosis in human CRC cells, whereas TUSC3 siRNA knock-down increased EGFR-signaling. Accordingly, in stage I/II node negative CRC patients ( n =156 cases) loss of TUSC3 protein expression was associated with poor overall survival. In sum, our data suggested that epigenetic silencing of TUSC3 may be useful as a molecular marker for progression of early CRC.

7041 Background: Venetoclax (Ven) is a selective, potent BCL-2 inhibitor. Ven + azacitidine (Aza) were associated with a combined complete remission (CR)/marrow CR (mCR) rate of 79% in a phase 1b study of patients (pts) with HR-MDS. Here we compared two different dose modification strategies to manage expected hematologic toxicities in two safety expansion cohorts with similar follow-up periods. Methods: Pts ≥18y diagnosed with treatment-naïve IPSS intermediate-2 or high-risk MDS with ECOG ≤2 were enrolled. Aza 75 mg/m2 (iv or subQ daily) was administered for 7 days (d) and Ven was administered at 400 mg for 14d in each 28d cycle. In both cohorts, dose modification during Cycle 1 was not recommended; dose modifications in subsequent cycles were prescribed for AEs. In Safety Expansion Cohort 1 (SE1), either Aza or Ven were initially reduced according to investigator’s choice for significant neutrophil or platelet toxicity. Dose reductions per protocol were 33% for Aza and 50% for Ven (for 14d each cycle). In subsequent cycles, Ven duration could be shortened to 9d of each cycle. In Safety Expansion Cohort 2 (SE2), dose modification guidelines recommended stepwise reductions, first in Aza dose (first to 50 mg/m2, then 36 mg/m2) and subsequently in Ven duration to 7d of each cycle (Ven 400 mg). The impact of each dose modification strategy on safety and efficacy in SE1 vs SE2 was compared. Worsening of treatment-emergent adverse events (TEAE) grades from baseline (BL) was analyzed by cycle. Responses were evaluated using IWG 2006 criteria. Analyses included all pts who received ≥1 dose of study drug. Results: We compared 22 pts in SE1 and 21 pts in SE2 with median (range) follow-up of 7.5 (1.0–8.9) and 7.9 (1.8–10.1) mos, respectively. A similar frequency of ≥ G3 hematologic TEAEs (approx %) were reported in SE1 and SE2, respectively, including anemia (14% and 33%), febrile neutropenia (46% and 48%), leukopenia (36% and 19%), neutropenia (55% and 48%) and thrombocytopenia (32% and 38%). Infections (59% and 38%) were more frequent in SE1 than SE2. In a longitudinal analysis, there were more TEAE grade increases from BL to Cycle 1 in SE2 vs SE1. This could be accounted by pts in SE1 and SE2 having unbalanced susceptibility to AEs at BL, as SE1 and SE2 pts received identical Aza + Ven doses in Cycle 1. Response rates were identical: 86% of pts in both SE1 and SE2 had CR or mCR. For pts with mCR, hematologic improvement occurred in 50% of SE1 and 46% of SE2 pts. Conclusions: No obvious hematologic differences were observed when reducing Aza before Ven (SE2) in MDS compared to investigator’s choice (SE1). Both approaches had a similar acceptable safety profile without compromising efficacy for pts with HR-MDS. Clinical trial information: NCT02942290. [Table: see text]

Patients with monoclonal gammopathy of undetermined significance (MGUS) have a higher risk for the development of concomitant primary cancers such as multiple myeloma (MM) and myelodysplastic syndrome (MDS). We report the case of patient initially suffering from MGUS of the IgG lambda subtype for more than 10 yr, which evolved to MM and MDS with deletion (5q) with severe pancytopenia. Due to pancytopenia, he received dose-reduced treatment with lenalidomide and dexamethasone. He achieved an ongoing transfusion independency after about 1 month of treatment. Bone marrow taken 14 months after start of treatment showed a complete cytogenetic response of the del(5q) clone and a plasma cell infiltration below 5%. In contrast to the development of MM in MGUS patients, the subsequent occurrence of MDS after diagnosis of MGUS is infrequent. Moreover, the biological association of MDS with MGUS is not sufficiently understood, but the non-treatment-related occurrence supports the pathogenetic role of pre-existing alterations of stem cells. Here, we summarize data on concomitant MDS and MGUS/MM with particular emphasis on molecular aspects.

Acute promyelocytic leukemia (APL) is a subtype of myeloid leukemia characterized by differentiation block at the promyelocyte stage. Besides the presence of chromosomal rearrangement t(15;17), leading to the formation of PML-RARA (promyelocytic leukemia-retinoic acid receptor alpha) fusion, other genetic alterations have also been implicated in APL. Here, we performed comprehensive mutational analysis of primary and relapse APL to identify somatic alterations, which cooperate with PML-RARA in the pathogenesis of APL. We explored the mutational landscape using whole-exome (n=12) and subsequent targeted sequencing of 398 genes in 153 primary and 69 relapse APL. Both primary and relapse APL harbored an average of eight non-silent somatic mutations per exome. We observed recurrent alterations of FLT3, WT1, NRAS and KRAS in the newly diagnosed APL, whereas mutations in other genes commonly mutated in myeloid leukemia were rarely detected. The molecular signature of APL relapse was characterized by emergence of frequent mutations in PML and RARA genes. Our sequencing data also demonstrates incidence of loss-of-function mutations in previously unidentified genes, ARID1B and ARID1A, both of which encode for key components of the SWI/SNF complex. We show that knockdown of ARID1B in APL cell line, NB4, results in large-scale activation of gene expression and reduced in vitro differentiation potential.

Asunercept (APG101) is a well-tolerated CD95-ligand inhibitor that showed promising efficacy in a prospective, single-arm phase I study in anemic, transfusion-dependent patients with low and intermediate risk myelodysplastic syndrome (MDS). In this retrospective post hoc analysis, serum levels of biomarkers were measured in study patients focusing on cytokines associated with erythropoiesis, inflammation, apoptosis, bone marrow fibrosis, and inflammasome activity. Baseline serum biomarkers were correlated with treatment response, in order to propose a hypothetical responder serum profile. After an updated median follow-up of 54 months (range 7&ndash, 65), response to asunercept was associated with improved overall survival (at 3-years: 67% [95%CI 36&ndash, 97] versus 13% [95%CI 0&ndash, 36] in responders versus non-responders, respectively). Higher baseline values of interleukin-18 (IL-18), S100 calcium-binding protein A9 (S100A9) and soluble p53 were predictive of non-response to asunercept (area under the receiver operating characteristic curve 0.79&ndash, 0.82). Furthermore, non-responding patients showed a distinct, pro-inflammatory serum cytokine profile which was persistent throughout the first half of the treatment phase and appeared unaffected by asunercept. Although prospective validation is required, our post hoc analysis suggests that serum cytokine profiling based on IL-18, S100A9 and soluble p53 may represent an approach to identify and select low-risk MDS patients most likely to benefit from asunercept treatment.

We investigated the role of copy number alterations to refine risk stratification in adult Philadelphia chromosome positive (Ph)+ ALL treated with tyrosine kinase inhibitors (TKI) and allogeneic stem cell transplantation (aSCT). 97 Ph+ ALL patients (median age 41 years, range 18-64 years) within the prospective multicenter GMALL studies 06/99 (n=8) and 07/2003 (n=89) were analysed. All patients received TKI and aSCT in first complete remission (CR1). Copy number analysis was performed with SNP arrays and validated by multiplex ligation-dependent probe amplification (MLPA). The frequencies of recurrently deleted genes were: IKZF1, 76%, CDKN2A/2B, 45%, PAX5, 43%, BTG1, 18%, EBF1, 13%, ETV6, 5%, RB, 14%. In univariate analyses, the presence of CDKN2A/2B deletions had a negative impact on all endpoints: overall survival (p=0.023), disease free survival (p=0.012) and remission duration (p=0.036). The negative predictive value of CDKN2A/2B deletions was retained in multivariable analysis along with other factors such as timing of TKI therapy, intensity of conditioning, achieving remission after induction phase I and BTG1 deletions. We therefore conclude that acquired genomic CDKN2A/2B deletions identify a subgroup of Ph+ ALL patients, who have an inferior prognosis despite aSCT in CR1. Their poor outcome was attributable primarily to a high relapse rate after aSCT.

To date risk stratification in acute promyelocytic leukemia (APL) is based on highly dynamic leukocyte and platelet counts only. To identify a more robust risk stratification model, a molecular risk score was developed based on expression levels of the genes BAALC, ERG and WT1. Hereby, the main focus was on prediction of relapse. The integrative risk score divided patients into two groups with highly significant differences in outcome. It discriminated a high risk group with a high incidence of relapse successfully from a low risk group with no APL-related events after achievement of first remission. Especially the concurrent presence of molecular risk factors showed to be a negative prognostic factor in APL. The molecular risk score might be a promising approach to guide monitoring of APL patients and therapeutic decisions in the future.

Wilms' tumor 1 gene (WT1) is known to be highly expressed in acute promyelocytic leukemia (APL) but information on its impact on prognosis is lacking. WT1 expression was analyzed in bone marrow samples of 79 patients with APL at initial diagnosis. Patients had a differing outcome according to their level of WT1 expression. In patients who achieved a complete remission (CR), low or high WT1 expression was significantly associated with inferior overall survival (OS) compared to intermediate WT1 expression (49% for WT1high vs. 63% for WT1low vs. 93% for WT1int; p=0.008). Moreover, there were significant differences in relapse-free survival (RFS) between the three expression groups (42% for WT1high vs. 63% for WT1low vs. 83% for WT1int; p=0.047). In multivariable analysis WT1 expression showed an independent prognostic impact on OS of responders to induction therapy. In conclusion, the level of WT1 expression can add prognostic information in APL risk stratification.

Introduction Although treatment of acute promyelocytic leukemia (APL) has evolved dramatically during the past decades, especially with the introduction of all-trans retinoic acid, risk stratification remains an important issue. To date, relapse risk can be predicted by leukocyte and platelet counts only. In the present report, we present a validation study on 3 candidate genes and a newly developed molecular risk score for APL in 2 independent patient cohorts. Patients and Methods An integrative risk score combining the expression levels of BAALC , ERG , and WT1 was calculated for 79 de novo APL patients from the original cohort and 76 de novo APL patients from a validation cohort. Gene expression analysis was executed the same for both cohorts, and the results regarding the effect on patient outcomes were compared. Results The expression levels of BAALC , ERG , and WT1 were similar in both cohorts compared with the healthy controls. The relapse and survival rates were not different between the low- and high-risk patients according to the Sanz score. However, application of the molecular risk score on the validation cohort distinctly discriminated patients according to their risk of relapse and death just as in the original APL cohort, although single gene analyses could not reproduce the negative prognostic impact. Conclusion The analysis clearly validated the prognostic effect of the integrative risk score on the outcome in APL patients. The value was further empowered because the single gene analyses did not show similar results. Whether the integrative risk score retains its prognostic power in the chemotherapy-free setting should be investigated further.

Overexpression of transketolase-like gene 1 (TKTL1) on RNA and protein level has been linked to tumour progression, metastasis and unfavourable patient outcome in many solid tumours. Chronic myeloid leukaemia (CML) cells show metabolic characteristics resembling deviations observed in TKTL1 overexpressing solid tumour cells. We therefore sought to evaluate TKTL1 gene expression in different phases of CML.A total of 120 peripheral blood samples from 69 patients in various phases of CML and 21 healthy individuals were investigated. TKTL1 expression levels were determined by real-time quantitative polymerase chain reaction using LightCycler technology and normalised against beta-glucuronidase expression.A significantly lower TKTL1 expression was found in chronic phase (CP) CML patients compared to healthy controls. Lowest expression levels were observed in patients during blast crisis (BC). Baseline TKTL1 expression in CP patients did not have value in prognostication of subsequent favourable or dismal outcome. Further, more mature granulocytes showed significantly higher TKTL1 expression compared to immature CD34+ and CD34-/CD33+ cells both in healthy controls and in CML patients.TKTL1 expression levels appear to decline in the course of CML with lowest levels during BC. A potential reason is a shift of TKTL1-high-expressing mature granulocytes towards TKTL1-low-expressing immature cells and blasts.

Acute promyelocytic leukemia (APL) is a rare form of acute myeloid leukemia. The specific translocation t(15;17), which results in the fusion gene PML-RARA is the diagnostic and pathomechanistic hallmark of APL. By combination, treatment consisting of the differentiating agent all-trans retinoic acid (ATRA), which targets this molecular lesion, and cytotoxic chemotherapy, cure can be achieved in over 70% of patients. Recently, arsenic trioxide (ATO) has emerged to be the most active single agent in the treatment of APL. Previous studies employing ATO in relapse settings reported average complete remission rates of 85% and a mean overall survival of over 60%. In recent approaches installing ATO in first-line treatment, ATO-induced response rates comparable to previous combination regimen. The results of these newer studies indicate that the backbone of chemotherapy can be dramatically reduced or completely replaced by ATO and ATRA with similar or even better outcome.

The contribution of molecular alterations in bone marrow mesenchymal stromal cells (BM-MSC) to the pathogenesis of acute myeloid leukemia (AML) is poorly understood. Thus we assessed genome-wide genetic, transcriptional and epigenetic alterations in BM-MSC derived from AML patients (AML BM-MSC). Whole-exome sequencing (WES) of AML BM-MSC samples from 21 patients revealed a non-specific pattern of genetic alterations in the stromal compartment. The only mutation present in AML BM-MSC at serial time points of diagnosis, complete remission and relapse was a mutation in the PLEC gene encoding for cytoskeleton key player Plectin in one AML patient. Healthy donor controls did not carry genetic alterations as determined by WES. Transcriptional profiling using RNA sequencing revealed deregulation of proteoglycans and adhesion molecules as well as cytokines in AML BM-MSC. Moreover, KEGG pathway enrichment analysis unravelled deregulated metabolic pathways and endocytosis in both transcriptional and DNA methylation signatures in AML BM-MSC. Taken together, we report molecular alterations in AML BM-MSC suggesting global changes in the AML BM microenvironment. Extended investigations of these altered niche components may contribute to the design of niche-directed therapies in AML.

In acute promyelocytic leukemia (APL), relapse occurs in about 15 % of cases and is a major cause for death. Molecular markers identifying patients at high risk for relapse are not well established. High expression of the transcription factor Ets-related gene (ERG) is associated with inferior overall survival (OS) and disease-free survival in different types of hematologic malignancies. There are no data available about the impact of ERG expression in APL. ERG expression levels were analyzed in bone marrow samples of 86 APL patients at initial diagnosis. High ERG expression was significantly associated with an inferior OS in patients who had reached first complete remission. It was also significantly correlated with inferior relapse-free survival (RFS) and time to relapse (i.e., relapse-free interval, RFI). In multivariate analysis, high ERG expression had an independent negative impact on RFS and RFI. High ERG expression was significantly associated with inferior OS, RFS, and RFI. Moreover, in multivariate analysis, it maintained its value as an independent negative prognostic factor with regard to RFS and RFI. Therefore, ERG expression might serve as a molecular marker for risk stratification in APL and might identify patients who could benefit from intensified treatment regimens.

Arsenic trioxide (ATO) is presently the most active single agent in the treatment of acute promyelocytic leukemia (APL). This review provides insights into the mode of action and the pharmacological properties of ATO, and summarizes the most relevant results of more than 20 treatment studies in relapsed or newly diagnosed APL published between 1997 and 2011. ATO acts by targeting multiple pathways in APL leading to apoptosis and myeloid differentiation. It induces complete remission without myelosuppression and causes only few adverse effects. In relapsed APL, ATO-based salvage therapy has been able to induce long-lasting remissions and possible cure in 50-81% of patients. In newly diagnosed APL, two main strategies are currently pursued. ATO is either included into induction therapy with the aim to minimize or eliminate chemotherapy, or it is incorporated as an additive into established first-line concepts with all-trans-retinoic acid and chemotherapy to reinforce their anti-leukemic efficacy. Recent results suggest a high efficacy of ATO in both concepts. In conclusion, experimental research and clinical studies have made contributions toward a better understanding of the molecular mechanisms induced by ATO in APL cells and have established this historic substance as an important candidate for the further improvement of APL therapy.

The analysis of genomic alterations in acute lymphoblastic leukemia (ALL) has provided new insights for prognosis and possible targets of novel therapies. In T-ALL the role of molecular abnormalities has still to be determined. Deregulated promoter hypermethylation of critical genes like PAX5 may have a significant impact on the course of ALL. Samples derived from 75 patients with ALL (B-ALL = 24, T-ALL = 51) and from healthy volunteers were analyzed. PAX5 expression was assessed by micro-array analysis (HG-U133plus 2.0) and correlated with promoter CpG island methylation of PAX5 using a pyrosequencing approach. The analyzed CpG marks in the promoter region of PAX5 were completely and uniformly unmethylated in the control group of healthy individuals. The T-ALL cases featured even higher methylation levels (median: 20%) with a strong variation of values of up to 85% methylation. Analysis of the association of altered methylation levels with gene expression data indicated a differential epigenetic regulation of PAX5 through promoter methylation which may contribute to the pathogenesis of this disease.

Introduction: Thrombocytopenia is a common complication among MDS patients. Thus, many patients are dependent on platelet (PLT) transfusions, which give short-term therapeutic relief but are also associated with considerable clinical risks. In this context, thrombopoietin receptor agonists (TRAs) are under investigation as alternative treatment option, albeit with the concern that these substances may promote adverse events in MDS. However, beside potential positive effects on thrombopoiesis in MDS patients the TRA Eltrombopag (EPAG) has also been shown to exert positive disease modifying effects in vitro (Roth et al., Blood 2012). Using a MDS xenograft model, we here investigate the efficacy of EPAG and its influence on clonal composition on primary patient derived MDS xenografts and present data from an ongoing study. Methods: Currently, samples from n=18 MDS patients (MDS del(5q)=2, MDS-MLD=6, MDS-RS-MLD=1 MDS-EB-1=2, MDS-EB-2=7) have been xenografted into NSG mice by intrafemoral co-injection of CD34+ hematopoietic stem cells and mesenchymal stromal cells using a modified protocol according to Medyouf et al., Cell Stem Cell 2014. Long term engraftment is assessed 12 weeks post-transplant by intrafemoral bone marrow (BM) biopsy and mice with positive human engraftment are subsequently treated with either EPAG (50mg/kg) or vehicle control for 18 weeks. During that time, the mice are bled every two weeks and BM aspiration is performed every six weeks. Human hematopoietic cells are FACS sorted. In peripheral blood, human PLTs are specifically and absolutely counted with a FACS assay based on hCD41+ cells and beads. To track clonal composition of MDS samples upon xenografting and EPAG treatment in comparison to placebo control, the original patient sample and the final MDS xenograft sample are being whole exome sequenced (WES). Interspersed time points are analyzed with a patient individual amplicon based deep sequencing approach (Mossner et al., Blood 2016) to calculate dynamics of variant allele frequencies (VAF) in dependency of treatment. Results: To date, n=12 patient samples have been analyzed for human engraftment after 12 weeks post-transplant. Of these, n=7 (58%) have shown positive human engraftment and are being treated with EPAG versus placebo. To this end, one case has been completely followed up, including final molecular analysis. This MDS high risk case (MDS-EB-2) with a clinical PLT count of 29x109 PLT/L was transplanted into n=3 NSG mice. While two mice treated with EPAG survived the complete duration of the experiment, the placebo mouse died prematurely due to severe weight loss after 6 weeks of treatment. Further, EPAG treatment led to an initial rise of human PLT levels, while the placebo treated mouse presented a continuous decline of human PLTs, showing the efficacy of EPAG on human xenografts in the model. This observation has been confirmed in another case currently still under treatment. Molecular tracking by WES confirmed MDS patient specific molecular lesions in the MDS xenograft such as monosomy 7 and the disease related mutations CBL, DNMT3A and EZH2 with VAFs of 83%/43%/23% respectively. The monosomy 7 was detectable in all mice. CBL and DNMT3A exhibited similar VAFs in mouse EPAG1 (VAF=100%/54%), EPAG2 (VAF=100%/34%) and placebo (VAF=100%/50%). The EZH2 mutation was only detected in mouse EPAG2 (VAF=11%). Interestingly, the placebo mouse acquired a de novo mutation of U2AF1 (VAF=10%), which was not detectable in the initial patient sample or the EPAG treated mice. This spliceosomal mutation is associated with a higher risk of transformation to AML and shorter survival (Graubert et al., Nat Genet 2012; Makishima et al., Blood 2012). Conclusions: Our data show first proof of principle results that new treatment options can be tested successfully in a preclinical murine xenograft model of primary MDS patient samples in a placebo controlled experimental setting. This approach allows the performance of patient individual substance testing that can segregate substance specific effects from natural disease progression in the same patient. Clinical parameters such as human PLT production and molecular clonal composition can be measured with a high confidence in vivo. Our current data show preliminary support for the hypothesis that EPAG may be efficacious in increasing PLT production in MDS patients without adversely influencing the underlying clonal composition. Disclosures Nowak: Novartis: Research Funding.

Src kinases are involved in multiple cellular contexts such as proliferation, adhesion, tumor invasiveness, angiogenesis, cell cycle control and apoptosis. We here demonstrate that three newly developed dual selective Src/Abl kinase inhibitors (SrcK-I) (AZM559756, AZD0530 and AZD0424) are able to induce apoptosis and cell cycle arrest in BCR-ABL, c-KIT and platelet-derived growth factor-negative lymphoma cell lines. Treatment of DOHH-2, WSU-NHL, Raji, Karpas-299, HUT78 and Jurkat cells with SrcK-I revealed that the tested substances were effective on these parameters in the cell lines DOHH-2 and WSU-NHL, whereas the other tested cell lines remained unaffected. Phosphorylation of Lyn and in particular Lck were affected most heavily by treatment with the SrcK-I. Extrinsic as well as intrinsic apoptosis pathways were activated and elicited unique expressional patterns of apoptosis-relevant proteins such as downregulation of survivin, Bcl-XL and c-FLIP. Protein levels of c-abl were downregulated and Akt phosphorylation was decreased by treatment with SrcK-I. Basal expression levels of c-Myc were notably lower in sensitive cell lines as compared with nonsensitive cell lines, possibly providing an explanation for sensitivity versus resistance against these novel substances. This study provides the first basis for establishing novel SrcK-I as weapons in the arsenal against lymphoma cells.

The aminopyrimidine inhibitor AMN107 (Nilotinib) was rationally designed to antagonize the aberrant tyrosine kinase activity of Bcr-Abl-positive cells. We here evaluated, whether AMN107 is also able to induce apoptosis in Bcr-Abl-negative cells of lymphatic origin. The B-cell lines DOHH-2 and WSU-NHL and the T-cell lines Jurkat and HUT78 were incubated with increasing amounts of AMN107 corresponding to clinically achievable dosages. Subsequently, induced molecular changes were assessed by FACS analysis, Western blot, and enzyme activity assays. Although AMN107 exhibited only a minor apoptosis-inducing effect in the T-cell lines, it exerted a considerable, dose-dependent cytotoxicity in the B-cell lines. Using selective caspase-inhibitors, we show that apoptosis in responder cell lines critically relies on activation of caspase-6 and caspase-9. Cell lines sensitive and resistant towards AMN107 can be discriminated by their differential expression of Src-kinases. Although the AMN107-sensitive cell lines DOHH-2 and WSU-NHL exhibited low or no expression of the Src-kinases Lck, phosphorylated Lck, and Yes with a concomitant high expression of Hck, Lyn, and phosphorylated Lyn, the expression pattern of these kinases was inverse in the AMN107-resistant T-cell lines. In conclusion, this is the first report providing evidence that activity of AMN107 is not restricted to Bcr-Abl, c-Kit, or PDGFR-positive cells, but also extends to lymphatic cell lines of B-cell origin.

The pyrimidine analogue Ara-C and the purine analogues fludarabine and cladribine (2-CdA) are essential compounds in the treatment of acute myeloid leukemia (AML). Inhibition of cell proliferation and induction of apoptosis are the major mechanisms of cytotoxic agents to cause tumor cell death. Therefore, we studied whether Ara-C in combination with the purine analogues exerts synergistic or antagonistic effects on cell proliferation, phosphatidylserine exposure and disruption of mitochondrial membrane potential (MMP) in the AML cell lines HL60 and HEL. Furthermore, effects of the combination of Ara-C with bendamustine, a new bifunctional agent with alkylating activity and a purine nucleus, was investigated. Assessment by combination index analysis showed that Ara-C combined with fludarabine or bendamustine exhibited additive to antagonistic effects on inhibition of cell proliferation, induction of apoptosis as well as on disruption of mitochondrial membrane potential, independent of a simultaneous or consecutive (purine analogues before Ara-C) incubation schedule. In contrast, the combination of Ara-C with 2-CdA exclusively yielded synergistic effects. While inducing IC50 levels of apoptosis neither the antagonistic nor the synergistic drug combinations caused a specific expression pattern of apoptosis-associated proteins such as the pro- or antiapoptotic Bcl-2 family members, executioner caspases, IAPs (inhibitor of apoptosis proteins), proapoptotic Par-4, PARP, or p53. In conclusion, we here demonstrate that the in vitro efficacy of drug combinations containing Ara-C and purine analogues depends on the purine analogue applied, whereas incubation schedules or escalating dosages do not contribute to the synergistic effects.

We have read with great interest the recent editorial discussing future perspectives in the treatment of patients with aplastic anemia (AA).[1][1] The authors emphasized the potential role of eltrombopag (EPAG), which is currently only licensed as second-line treatment for patients with immune

Introduction:Particularly in low risk MDS, a pro-apoptotic milieu has been described with increased levels of apoptosis-promoting factors such as tumor necrosis factor and fas ligand (CD95 ligand). Evidence exists that in low risk MDS increased apoptosis of erythroid progenitors mediated via CD95 activation results in peripheral cytopenia. APG101 is a fusion protein consisting of the extracellular domain of human CD95 and the Fc domain of human IgG1. APG101 binds to CD95 ligand on effector cells as well as to soluble ligand, thus blocking the interaction between CD95 and its ligand. Here we report on results of a phase I study in transfusion-dependent low risk MDS patients treated with APG101. Primary objectives were safety and tolerability of APG101. Secondary objectives were hematologic, cytologic and cytogenetic response rates using modified International Working Group (IWG) response criteria (Cheson et al., 2006), incidence and time to leukemic progression as well as overall survival (OS) at 37 weeks. Furthermore, this study was focused on the depiction of molecular and functional changes underlying the stem cell defect in MDS including age related changes and high-throughput molecular profiling to evaluate the biological effect of APG101 in patients with lower risk MDS. Methods: The study was performed according to ICH-GCP guidelines and the Declaration of Helsinki as an open-label, non-randomized study for up to 37 weeks including an initial 12 weeks treatment phase with APG101 and a follow-up period of 25 weeks. 400 mg of APG101 were given every week as an intravenous (i.v.) infusion to the first 6 patients, 100 mg APG101 were given to all further patients. Bone marrow aspirates were obtained during the screening period (baseline), at the end of treatment (EOT, week 13), at week 25 (follow up) and at week 37 (End of Study) with subsequent comprehensive cytologic, cytogenetic, molecular and immunophenotypic analyses. In order to track clonal development and heterogeneity, methylcellulose assays on isolated CD34+cells from bone marrow aspirates at the different time points were performed and subjected to amplicon deep sequencing to detect gene mutations prior to APG101 dosing and to follow the mutational allele burden during and after treatment. Results: A total of 29 patients were screened for this study. Twenty patients received at least one dose of APG101, 17 patients completed the treatment phase and 15 patients completed the entire study including the follow-up phase. Median age was 74.5 years (range 56-82). WPSS categories were low in 19 patients and intermediate in 1 patient, respectively. Except for two patients with RCMD-RS and RARS, all others were classified as RCMD (WHO 2008). According to the exclusion criteria, none of the patients showed a medullary blast count ≥ 5%. Quantification of the allele burden of pre-existing mutations (mutations of ASXL1, SF3B1, TTBK, del(ETV6) and IDH2, SRSF2, SPEG2, BRCC3, NF1) showed no expansion of the mutated clones during the course of treatment. One patient, however, was reported with leukemic progression and AML transformation. One patient died from sepsis due to pre-existing neutropenia. Ex vivo differentiation analyses revealed an increase in CFU-E/BFU-E forming capacity. With regard to efficacy, an improvement in Hb level was observed in 6 patients at various assessment periods in this study. In 8 patients, a decrease in transfusion frequency from treatment until EOS was observed. Conclusions: APG101 is a very well tolerable compound in transfusion-dependent lower risk MDS patients comprising mostly of elderly patients. Risk of AML progression was not elevated. Deep amplicon sequencing did not show any signs of expansion of preexisting malignant clones during therapy, i.e. APG101 did not provide these clones with a survival benefit. Analysis of efficacy as secondary objective revealed that APG101 has the potential to improve hematopoiesis in MDS patients. Therefore, APG101 is an interesting compound for further clinical studies. Disclosures Fricke: Apogenix AG: Employment. Kunz:Apogenix AG: Employment.

Introduction: Risk stratification in acute promyelocytic leukemia (APL) is based on clinical parameters, namely leukocyte and platelet counts at initial diagnosis as combined in the Sanz Score. However, during the last years the influence of additional molecular genetic markers on prognosis of APL patients has been postulated. In 2015 we published the results of a molecular risk score integrating expression data of the genes brain and acute leukemia, cytoplasmic (BAALC), ets' related gene (ERG) and Wilms' Tumor 1 (WT1) with strong independent influence on outcome and relapse risk of APL patients treated in the German AMLCG studies (Hecht et al., Leuk Res 2015). The aim of our study was to validate our data in an independent patient cohort. Methods: In cooperation with the German SAL (Study Alliance Leukemia) group we obtained a validation set of samples of mononuclear cells derived from the bone marrow of 76 patients with confirmed diagnosis of APL prior to therapy. The validation cohort consisted of 37 female and 39 male patients with a median age of 50 years (range 20-82 years; Table 1). Patients were diagnosed and treated between 2000 and 2014 mostly with an ATRA plus Idarubicin based induction therapy followed by Sanz score-dependent consolidation and maintenance chemotherapy. RNA was extracted using the AllPrep DNA/RNA Mini Kit and cDNA was synthesized using 500µg of RNA with a QuantiTect Reverse Transcription Kit (both Qiagen, Hilden, Germany). Expression levels of BAALC, ERG and WT1 were then analyzed using quantitative real-time RT-PCR with the same conditions and primers as used in the original test cohort and the same calibrator cDNA from cell lines was used for the analysis. The following gene expression levels were defined as negative risk factors in preceding studies: BAALC expression ≥25th percentile (BAALChigh), ERG expression ≥75th percentile (ERGhigh) and WT1 expression ≤25th percentile or ≥75th percentile (WT1low or high). The integrative risk score was calculated as described before: For the presence of one of the mentioned risk factors, one scoring point was assigned to a respective patient, i.e. a maximum of 3 points (one point for BAALChigh, ERGhigh and WT1low or high, respectively) and a minimum of 0 points (i.e. presenting with none of the aforementioned risk factors). Overall survival (OS), relapse free survival (RFS) and cumulative incidence of relapse (CIR) were calculated using the Kaplan-Meier method. Results: The expression of the three genes BAALC, ERG and WT1 compared to healthy controls were exactly the same as in the original cohort. Application of the molecular risk score on APL patients of the validation cohort clearly discriminated patients according to their risk comparable to the original APL cohort (Figure 1). Patients with 0 points had a very good prognosis with no deaths or relapses, whereas patients with 3 points (i.e. concurrent presence of all three risk factors) had a very poor outcome with an OS of 51%, a RFS of 50% and a CIR of 38%. The differences between patients with 1 and 2 points were less pronounced in the validation cohort. However, the statistical analyses in the validation cohort did not yield significance. As the main reason we assume that the validation cohort altogether showed a significantly improved OS and RFS compared to the original cohort which was treated a decade earlier, so differences between the subgroups could not be that pronounced. For both cohorts stratification by the Sanz Score did not show significant differences in outcome (analysis for RFS p=0.46 in original cohort and p=0.44 in validation cohort). Conclusion: A validated molecular-based integrative risk score was able to define subgroups of APL patients with different outcome independently of the Sanz score. The validation of the strong influence of the combination of molecular risk factors is particularly interesting as the new analyses of the three genes BAALC, ERG and WT1 separately did not confirm the strong results of the single analyses of each gene. The discrimination of patients according to the risk score is evident though. This argues for their integration in future studies. Figure 1 Comparison of the original cohort and the validation cohort. Discrimination by the integrative risk score (0-3points) for OS, RFS and CIR. Figure 1. Comparison of the original cohort and the validation cohort. Discrimination by the integrative risk score (0-3points) for OS, RFS and CIR. Disclosures No relevant conflicts of interest to declare.

Acute promyelocytic leukemia (APL) is a subtype of myeloid leukemia characterized by differentiation block at the promyelocyte stage. Besides the presence of chromosomal rearrangement t(15;17), leading to the formation of PML-RARA (promyelocytic leukemia-retinoic acid receptor alpha) fusion, other genetic alterations have also been implicated in APL. Here, we performed comprehensive mutational analysis of primary and relapse APL to identify somatic alterations, which cooperate with PML-RARA in the pathogenesis of APL. We explored the mutational landscape using whole-exome (n=12) and subsequent targeted sequencing of 398 genes in 153 primary and 69 relapse APL. Both primary and relapse APL harbored an average of eight non-silent somatic mutations per exome. We observed recurrent alterations of FLT3, WT1, NRAS and KRAS in the newly diagnosed APL, whereas mutations in other genes commonly mutated in myeloid leukemia were rarely detected. The molecular signature of APL relapse was characterized by emergence of frequent mutations in PML and RARA genes. Our sequencing data also demonstrates incidence of loss-of-function mutations in previously unidentified genes, ARID1B and ARID1A, both of which encode for key components of the SWI/SNF complex. We show that knockdown of ARID1B in APL cell line, NB4, results in large-scale activation of gene expression and reduced in vitro differentiation potential.

e18552Background: Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis resulting in peripheral cytopenia. In low risk MDS, a pro-apoptotic milieu was found with increased ...

We evaluated the prognostic value of BAALC expression in 86 patients with acute promyelocytic leukemia (APL). At 10 years, the overall survival (OS) was 66% in all patients and 75% in patients who achieved a complete remission (CR). Patients in the BAALC(low) group showed an OS of 87% as compared to 60% in the BAALC(high) group (p=0.019). This difference was more pronounced in treatment responders (92% vs. 70%; p=0.035). In multivariate analyses low BAALC expression retained its prognostic relevance. In conclusion, BAALC expression analysis might be useful in further risk stratification in APL patients.

Background: Desmoid tumors are neoplastic proliferations of connective tissues. The mutation status of the gene coding for catenin (cadherin-associated protein) beta 1 (CTNNB1) and trisomy 8 on the chromosomal level have been described to have prognostic relevance. Patients and Methods: In order to elucidate new molecular mechanisms underlying these tumors, we carried out a molecular analysis with a genome-wide human high-density single-nucleotide polymorphism (SNP) array, in 9 patients. Results: Single samples showed numerical aberrations on chromosomes (Chrs) 20 and 6 with either trisomy 20 or monosomy 6. No trisomy 8 could be detected. Recurrent heterozygous deletions were found in Chr 5q (including the APC gene locus, n = 3) and Chr 8p23 (n = 4, containing coding regions for the potential tumor suppressor gene CSMD1). This novel deletion in 8p23 showed an association with local recurrence. In addition, structural chromosomal changes (gain of Chrs 8 and 20) were found in a minority of cases. Conclusion: The genomic alteration affecting the candidate gene CSMD1 could be important in the development of desmoid tumors.

To search for new copy number alterations (CNAs) in acute promyelocytic leukemia (APL), we analyzed DNA from leukemic blasts of 93 acute promyelocytic leukemia (APL) patients with Genome-Wide SNP 6.0 arrays (SNP-A). We identified 259 CNAs consisting of 170 heterozygous deletions, 82 amplifications, and 7 regions of copy number neutral loss of heterozygosity. One of the most common CNAs was a deletion on chromosomal subband 1q31.3 in 13 of 93 (14%) patients encompassing the coding regions for the microRNAs mir181a1/b1. In multivariable analysis with the covariates age, white blood cell count, platelet count, and FLT3-ITD/FLT3 D835 mutations we found that after adjustment for patients' age (P < 0.0001), patients with 2 or more CNAs detected by SNP-A had a higher risk of death (hazard ratio = 5.942, P = 0.0015) than patients with 0 or 1 CNA. Deletions of 1q31.3 were associated with a higher number of CNAs (median 2 vs. 8, P < 0.0001) and were a strong independent prognostic factor for an increased risk of relapse (hazard ratio = 28.9, P = 0.0031). This study presents a comprehensive assessment of new CNAs as pathomechanistically relevant targets and possible prognostic factors which could refine risk stratification of APL. © 2012 Wiley Periodicals, Inc.

Introduction: Insulin-like growth factor binding proteins (IGFBP) are carriers of insulin-like growth factors (IGFs). They prolong their half-life and modulate their availability and activity. The IGF-signaling system has been shown to have an important role in various solid cancers and hematologic malignancies. High levels of IGFBP2 and IGFBP7 have been associated with chemoresistance, relapse and inferior survival in different leukemias. Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML), which has been reported to have increased expression of IGFBP2. However, there is no data on its impact on prognosis. In addition, no data exist on IGFBP7 in APL. The aim of this study was to elucidate the influence on prognosis of both candidate genes in APL patients. Methods: Expression levels of IGFBP2 und IGFBP7 were retrospectively analysed in bone marrow (BM) samples at the time of initial diagnosis from 69 APL patients (42 female, 27 male) after informed consent. Median age of patients was 46 years (range 19 to 82 years). All patients were diagnosed and treated in the German AML Cooperative Group (AMLCG) studies. Treatment consisted of simultaneous ATRA and double induction chemotherapy including high dose ara-C, one cycle of consolidation chemotherapy and 3 years monthly maintenance chemotherapy. In patients older than 60 years, the second induction cycle was at the discretion of the treating physician. Three patients (4%) received an induction of ATRA and an anthracycline without ara-C. BM samples of 22 healthy volunteers served as a control group. Multiplex reverse transcriptase quantitative real-time PCR (qRT-PCR) was performed on a LightCycler® 480 (Roche, Mannheim, Germany) PCR system. Glucose-6-phosphat isomerase was used as a housekeeping gene. For quantification of relative expression values a modified delta-delta CT calculation model according to Pfaffl was used after determination of PCR efficiencies. cDNA from the cell line K562 served as a calibrator in each run. All reactions were performed in triplicates. IGFBP2 expression groups were defined as follows: Patients with IGFBP2 expression below or equal the 25th percentile (IGFBP2low) were compared to patients with higher IGFBP2 expression (IGFBP2high). Overall survival (OS), relapse free survival (RFS) and the cumulative incidence of relapse (CIR) were calculated using the Kaplan-Meier method and a log-rank test was used to compare differences between the groups (p < 0.05). Results: Expression levels of IGFBP2 did not differ between APL patients and healthy controls. However, there was a significantly higher relapse rate in APL patients with low IGFBP2 expression (CIR: 25% in the IGFBP2low group vs. 5% in the IGFBP2high group; p=0.04). Accordingly, RFS of patients in the IGFBP2low group was also inferior (41% vs. 81% in the IGFBP2high group; p=0.0002; Fig. 1). The OS of patients who had responded to induction therapy was also influenced by IGFBP2 expression (OS of responders: 61% for IGFBP2low vs. 83% for IGFBP2high; p=0.02). However, there was no significant difference in the analysis of OS of all patients including patients who suffered early death. In contrast to these findings, IGFBP7 was expressed significantly lower in APL patients compared to healthy controls (p Conclusion: Of the two analysed IGFBP family members only IGFBP2 showed impact on the prognosis of APL patients. Remarkably, IGFBP2 was not overexpressed compared to healthy controls in our patient cohort. The reason might be that whole BM samples of healthy controls were used instead of subpopulations. Still, among the APL patients cohort its expression showed a strong influence on prognosis especially on relapse rate and RFS. To find low expression as a negative prognostic marker is surprising as for leukemias only high expression has been reported as a negative factor. However, IGFBP2 has been proposed to suppress tumor development through binding IGFs and preventing IGF-receptor driven tumorigenesis. This is supported by the fact that the IGFBP2 promotor is hypermethylated in various types of cancer. In summary, we identified low IGFBP2 expression as a novel prognostic marker for APL. Further investigations are warranted to clarify its possible role in leukemia. Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.

In a variety of malignant cells Prostate-apoptosis-response-gene-4 (Par-4) exhibits a pro-apoptotic influence sensitizing these cells to apoptosis-inducing agents by downregulating expression of Bcl-2. Considering the crucial role of Bcl-2 in the development of chemoresistance of acute myeloid leukemia (AML) cells, we here assessed the potential of Par-4 to down-regulate Bcl-2 and to induce apoptosis in the erythroleukemic cell line HEL. Testing a potential pro-apoptotic role of Par-4 upon incubation with various conventional chemotherapeutic drugs, novel agents such as the signal transduction inhibitor STI 571 and the histone deacetylase (HDAC)- inhibitor trichostatin A (TSA), as well as with the experimental substances Fas and TRAIL, we provide evidence that in the erythroleukemic cell line HEL expression of Par-4 is not sufficient to sensitize to any of these pro-apoptotic stimuli. We further demonstrate that – in contrast to previous reports in non-AML cells - Par-4 expression in HEL cells leads to an upregulation of Bcl-2. Moreover, Par-4-positive HEL cells exhibit a decreased level of the proapoptotic protein Bax as compared to Par-4- negative cells. In addition, Par-4 increases the expression of Daxx – whose downregulation is associated with augmented chemosensitivity – as well as expression of the procaspases-8, -9 and -10, whereas the levels of the procaspases-3 and -7 remain unaltered. In conclusion we here demonstrate that in the erythroleukemic cell line HEL – in contrast to other cell types – Par-4 fails to promote apoptosis and outline the underlying molecular mechanisms.