ALBERT

Description: Thrombomodulin (TM) is a predominantly endothelial transmembrane glycoprotein that modulates hemostatic function through a domain that controls thrombin-mediated proteolysis and an N-terminal lectin-like domain that controls inflammatory processes. To test the hypothesis that TM is a determinant of malignancy and dissect the importance of these functional domains in cancer biology, metastatic potential was evaluated in TMPro mice expressing a mutant form of TM with reduced thrombin affinity and TMLeD mice lacking the N-terminal lectin-like domain. Studies of TMPro mice revealed that TM is a powerful determinant of hematogenous metastasis. TMPro mice exhibited a strongly prometastatic phenotype relative to control mice that was found to result from increased survival of tumor cells newly localized to the lung rather than any alteration in tumor growth. The impact of the TMPro mutation on metastasis was dependent on both tumor cell-associated tissue factor and thrombin procoagulant function. In contrast, expression of a mutant form of TM lacking the lectin-like domain had no significant impact on metastasis. These studies directly demonstrate for the first time that TM-mediated regulation of tumor cell-driven procoagulant function strongly influences metastatic potential and suggest that endothelial cell-associated modulators of hemostasis may represent novel therapeutic targets in limiting tumor dissemination.

Description: Introduction Elderly non-transplant eligible newly diagnosed multiple myeloma (nte-NDMM) patients also benefit from novel therapies, however, overall survival (OS) is inferior in unfit and frail compared to fit patients as defined by the International Myeloma Working Group (IMWG) frailty index. This is caused by a high discontinuation rate due to toxicity. Therefore, a less toxic effective treatment for unfit and frail patients is needed. In view of the favorable safety profile of ixazomib (Ixa) and daratumumab (Dara), we investigated the efficacy and feasibility of treatment with Ixa and Dara plus low dose dexamethasone (Ixa-Dara-dex) in unfit and frail patients. This trial was registered at www.trialregister.nlwww.trialregister.nl as NTR6297. Methods In this prospective multicenter phase II trial, treatment consisted of nine 28 day-induction cycles consisting of Ixa 4 mg (days 1, 8, 15), Dara 16 mg/kg (cycle 1-2: days 1, 8, 15, 22; cycle 3-6: days 1, 15; cycle 7-9: day 1) and dex (in combination with Dara; cycle 1-2: 20 mg; subsequent cycles 10 mg) followed by maintenance therapy with Ixa (days 1, 8, 15, 29, 36, 43) and Dara (day 1) of 8-week cycles, until progression for a maximum of 2 years. A pre-specified efficacy analysis was planned for the first eligible 23 unfit and 23 frail patients separately at the time the data of the first 9 cycles induction therapy was available. Inclusion criteria were unfit or frail NDMM patients according to the IMWG frailty index. Main exclusion criteria were severe cardiac dysfunction, chronic obstructive pulmonary disease with an FEV1

Description: Key Points REP is an active combination in MM patients refractory to lenalidomide. REP is an all-oral and generally well-tolerated regimen.

Description: Introduction A triplet combination including a proteasome inhibitor (PI) and an IMiD has shown significant efficacy in newly diagnosed multiple myeloma (NDMM) patients. A role for maintenance therapy with the PI bortezomib has been suggested in non-head to head comparisons. Therefore, we investigated the efficacy and feasibility of an oral regimen including induction therapy with ixazomib in combination with thalidomide and dexamethasone, followed by a randomization between maintenance therapy with ixazomib or placebo in elderly non-transplant eligible (nte) NDMM. We here report the final analysis of induction therapy and preliminary results of the randomization phase of the study. This trial was registered at www.trialregister.nl as NTR4910. Methods In this prospective multicenter phase II trial nte-NDMM 143 patients were treated with 9 28 day-cycles consisting of ixazomib 4 mg (day 1, 8, 15), thalidomide 100 mg (day 1-28) and dexamethasone 40 mg (day 1, 8, 15, 22) followed by randomization between either ixazomib or placebo (both day 1, 8, 15/28 days) until progression. Primary objectives were comparison of progression free survival (PFS) between maintenance therapy with ixazomib or placebo (hypothesized hazard ratio (HR) 0.39) and to determine the overall response rate (ORR) of induction therapy. Frailty was assessed by a modification of the IMWG frailty index based on age, the Charlson Comorbidity Index and the WHO performance as a proxy for (instrumental) Activities of Daily Living (scoring WHO 0 as 0 points, WHO 1 as 1 point, and WHO 2-3 as 2 points). High risk cytogenetics was defined as del17p, t(4;14) and/or t(14;16). Results The median follow up (FU) from registration is 26.4 months (range 0.9-41.0 months). Patient characteristics are presented in table 1. Following induction treatment ORR (i.e. ≥PR) was 81% (95% confidence interval (CI) 74-87%), ≥ VGPR 47% (95% CI 38-55%) and ≥ CR 9% (95% CI 5-15%). Age ≥76 years, frailty (unfit or frail) or high cytogenetic risk did not affect the rate and quality of response. Median PFS from registration for all patients was 14.3 months (95%-CI 11.8-16.8). Frailty did not affect PFS. The median PFS for high risk and standard risk disease was comparable; 12.4 months (95%-CI 7.3-20.0) versus 14.6 months (95%-CI 11.5-17.4) respectively. The OS from registration at 18 months was 85% (95% CI 77-90). This was 90% (95% CI 72-97), 92% (95% CI 78-97) and 74% (95% CI 61-84) for fit, unfit and frail patients respectively. Seventy-eight patients (55%) were randomized. The reasons for not being randomized were toxicity (17% [24/143]), progressive disease (15% [21/143]), death (3% [5/143]) and other reasons (10% [15/143]). Median FU from randomization is 18.6 months (range 9.0-31.5 months). Baseline characteristics of randomized patients separately are presented in table 1. Upgrade of response occurred in 13% of patients receiving placebo and 10% of patients receiving ixazomib. The median PFS from randomization was 8.4 months (95%-CI 3.0-13.8) in the placebo arm and 10.1 months (95%-CI 5.6-24.1) in the ixazomib arm (p=0.47, figure 1). The OS from randomization at 18 months was 92% (95%-CI 77-97) in the placebo arm and 100% in the ixazomib arm (p=0.85). Toxicity is presented in table 2. The incidence of neuropathy was low; 8% grade 3 (mainly during thalidomide treatment; 5%) and no grade 4. There was no new onset neuropathy during ixazomib maintenance. During induction 24/143 (17%) patients discontinued therapy due to toxicity; 11 thalidomide-related neurotoxicity, 3 infection, 3 skin toxicity, 2 gastro-intestinal (GI) toxicity and 5 other. During maintenance 4/38 (11%) in the placebo (3 neurotoxicity and 1 other) versus 4/39 (10%) in the ixazomib arm (3 neurotoxicity and 1 GI) discontinued therapy due to toxicity. Discontinuation due to toxicity was comparable across age and frailty groups. Conclusion Induction treatment with 9 cycles of ITd in nte NDMM results in a high ORR of 81%, with 47% ≥ VGPR, independent of age, frailty status and cytogenetic risk. Our placebo controlled randomized phase II trial did not show an improvement in response and PFS with ixazomib maintenance therapy until progression. Ixazomib maintenance did not result in additional toxicity as compared to placebo. Disclosures Zweegman: Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corp.: 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, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Schjesvold:Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy; Bayer: Consultancy; Adaptive: Consultancy; Janssen: Consultancy, Honoraria, Research Funding; Oncopeptides: Consultancy; Abbvie: Honoraria; Novartis: Honoraria. Levin:Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. van de Donk:Janssen Pharmceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Research Funding. Sonneveld:Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Karyopharm: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; BMS: Honoraria, Research Funding. Abildgaard:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding.

Description: T-cell acute lymphoblastic leukemia (T-ALL) is mostly characterized by specific chromosomal abnormalities, some occurring in a mutually exclusive manner possibly delineating specific T-ALL subgroups. One subgroup, including MLL-rearranged, CALM-AF10 or inv(7)(p15q34) cases, is characterized by elevated expression of HOXA genes. Using a gene expression based clustering analysis of 67 T-ALL cases with recurrent molecular genetic abnormalities and 25 samples lacking apparent aberrations, we identified 5 new cases with elevated HOXA levels. Using array-CGH, a cryptic and recurrent deletion, del(9)(q34.11q34.13), was exclusively identified in 3 of these 5 cases. This deletion results in a conserved SET-NUP214 fusion product, that was also identified in the T-ALL cell line LOUCY. SET-NUP214 binds in the promoter regions of specific HOXA genes, where it interacts with CMR1 and DOT1L leading to the transcriptional activation of HOXA genes. Targeted inhibition of SET-NUP214 by siRNA abolished expression of HOXA genes, inhibited proliferation and induced differentiation in LOUCY but not in other T-ALL lines. We conclude that SET-NUP214 contributes to the pathogenesis of T-ALL by enforcing T-cell differentiation arrest.

Description: Introduction Multiple Myeloma (MM) is a heterogeneous disease with diverse gene expression patterns (GEP) across patients. This has led to the development of various signatures allowing virtual karyotyping, defining different clusters of patients, and prognostication by high risk signatures (e.g. EMC92/SKY92). Several GEP datasets exist, but may have scaling/offset differences (batch effects) in the data, e.g. due to differences in reagents used, location, etc. Batch wise normalization approaches can reduce batch effects, and have allowed successful validation of those signatures across independent datasets. Batch wise normalization requires groups of patients that have a similar distribution of clinical characteristics, and hence cannot be applied on single patients. Here we demonstrate the validity of applying GEP algorithms on single patients using the MMprofiler, enabling the application of GEP in a routine clinical setting. Materials and Methods The MMprofiler GEP assay is a standardized assay from bone marrow to data analysis and result reporting. It was used for 77 MM patients that were enrolled in the HOVON87/NMSG18 trial (73 patients) or HOVON95/EMN02 trial (4 patients). A representative reference set of 30 HOVON patients was selected from which normalization parameters were derived, to be used for normalization of a single sample against this HOVON reference dataset. The remaining 47 samples served as an independent set of samples. In addition, we have also used the publicly available GEP data from 247 patients (MRC-IX trial) as independent samples. This MRC-IX dataset has been produced using different reagents and sample work-up procedures. Therefore, it is likely that a batch effect will exist relative to the HOVON reference dataset, which may influence correctness of single sample analyses. The GEP data from the 47 and 247 independent samples were normalized using two approaches. Firstly, by batch wise mean variance normalization (i.e. across the 47 and 247 patient batches separately). And secondly, by single sample normalization using the normalization parameters from the initial 30 HOVON samples. Subsequently, several classifiers (EMC92/SKY92 etc.) were applied to the data, and their results were compared between the two normalization approaches. Results Figure 1 shows the EMC92/SKY92 scores that were obtained after batch normalization (x-axis) and single sample normalization (y-axis). For the 47 HOVON samples there is a high degree of concordance with data points close to the identity line (y=x). Only 2 out of the 47 samples would switch assignment, which is not unexpected since those 2 samples are really close to the threshold (e.g. might also switch due to technical variation). For the MRC-IX dataset, based on single sample normalization more patients would be predicted as high risk (87 (35.2%) instead of 52 (21.0%), see Figure 1), which is caused by a positive offset (i.e. intersect with the y-axis) due to the batch effect. For the Virtual t(4;14) classifier, both datasets have a very high concordance with 0 out 47 HOVON samples, and 5 out of 247 MRC-IX samples (but really close to the threshold) switching assignment (see Figure 1). Hence, even in the presence of a potential batch effect in the MRC-IX dataset, the single sample predictions are accurate. These data suggest that single sample normalization of microarray GEP is possible but requires the strict standardization of the MMprofiler assay and algorithms. Conclusions Scores for the EMC92/SKY92 signature were nearly equivalent when derived from the data following single sample normalization and batch normalization in the Skyline generated data. In the external dataset, a much higher discrepancy was found, highlighting the need to use highly standardized methods to generate Affymetrix GeneChip results. Further validation of this method is planned, and will include replicate runs systematically controlled for various conditions. Acknowledgments This research was performed within the framework of CTMM, the Center for Translational Molecular Medicine, project BioCHIP grant 03O-102. Figure 1. Scatterplots and confusion matrices of the batch (x-axis, columns) and single sample scores (y-axis, rows) of the EMC92/SKY92 signature (left), and Virtual t(4;14) classifier (right). Scores above/below the threshold correspond to high risk/standard risk (EMC92/SKY92) and positive/negative (Virtual t(4;14)). Figure 1. Scatterplots and confusion matrices of the batch (x-axis, columns) and single sample scores (y-axis, rows) of the EMC92/SKY92 signature (left), and Virtual t(4;14) classifier (right). Scores above/below the threshold correspond to high risk/standard risk (EMC92/SKY92) and positive/negative (Virtual t(4;14)). Disclosures Van Vliet: SkylineDX: Employment. Dumee:SkylineDx: Employment. de Best:SkylineDx: Employment. Sonneveld:SkylineDx: Membership on an entity's Board of Directors or advisory committees. van Beers:SkylineDX: Employment.

Description: Abstract 4876 Background. In newly diagnosed acute myeloid leukemia (AML) gene expression (RNA) profiling (GEP) (1) on Affymetrix GeneChips identifies homogeneous clusters that correlate with all favorable cytogenetic subtypes t(15;17), t(8;21) and inv(16)/t(16;16) and favourable CEBPA gene double mutants (2). We validated the use of GEP to detect NPM1 type A/B/D with specifically designed probes and validated the prognostic value of qualitative (high vs low) assays for single genes (EVI1 and BAALC). Aims. To develop and validate an in vitro diagnostic (CE-IVD) microarray for use in newly diagnosed AML. Methods. A custom Affymetrix microarray, the AMLprofiler, was produced that contains a combination of generic and specially designed probes. The array was tested following hybridisation of 261 AML training cases. Next, the AMLprofiler was evaluated in an independent cohort of 267 unselected newly diagnosed cases of AML (Erasmus University Medical Center & University Ulm). Results. During validation in 267 independent cases the AMLprofiler identified 18/17 inv(16), 7/7 t(15;17) and 16/16 t(8;21) AML's and 70/71 NPM1A/B/D cases. There was one false-positive inv(16) namely a t(11;16) translocation concurrent with MYH11 overexpression, suggesting involvement of the 16p13.1 breakpoint as in bona fide inv(16). There was 1 false-negative case of NPM1 type-D, which motivated algorithm retraining and subsequent independent re-validation, resulting in detecting 68/66 NPM1AB/D mutants in 143 Normal Karyotype AML cases. One of the FP cases is a true and relevant but non-A/B/D type mutant. The EVI1 and BAALC cut points were validated in an independent clinical cohort resulting in p 〈 0.05 in the logrank test for OS between high versus low expressing intermediate cytogenetic risk cases. Finally, reproducibility of the AMLprofiler assay is demonstrated across 5 independent laboratories in four countries. Summary/conclusions. We report the development of an AML gene expression RNA microarray for diagnostic use that can be applied by physicians in their own laboratories, to detect core binding AML, PML, NPM1 A/B/D mutant, CEBPA double mutant, high EVI1 and low BAALC AML cases for diagnostic use Disclosures: van Beers: Skyline Diagnostics: Employment, Patents & Royalties. de Best:Skyline Diagnostics: Employment. van Vliet:Skyline Diagnostics: Employment. Brand:Skyline Diagnostics: Employment. Burgmer:Skyline Diagnostics: Employment. de Quartel:Skyline Diagnostics: Employment. Dumee:Skyline Diagnostics: Employment. Provoost:Skyline Diagnostics: Employment. Valk:Skyline Diagnostics: Equity Ownership. van der Spek:Skyline Diagnostics: Equity Ownership. Vietor:Skyline Diagnostics: Employment, Equity Ownership. Lowenberg:Skyline Diagnostics: Equity Ownership.

Description: Abstract SCI-18 Activated protein C (APC) is a natural anticoagulant that blocks the amplification of the coagulation cascade via inactivation of factors Va and VIIIa. The APC/PC pathway is initiated by complex formation of thrombin, thrombomodulin (TM), and the endothelial protein C receptor (EPCR) allowing the conversion of zymogen protein C into its activated form. Based on the well-accepted view that coagulation contributes to cancer progression and that anticoagulant treatment may benefit some cancer patient groups, it has been hypothesized that the natural anticoagulant protein C pathway may also play a role in cancer progression. Interestingly, it has recently been shown that endogenous APC limits experimental metastasis of B16 melanoma cells in mouse lungs. Notably, an APC-blocking antibody dramatically increased the number of experimental lung metastasis although not due to diminished anticoagulant activity of APC but largely due to reduced APC-driven S1P1-mediated VE-cadherin-dependent vascular barrier enhancement. In line with these findings repeated administration of recombinant human APC as well as transgenic overexpression of EPCR also diminished experimental metastasis of B16 melanoma cells. It may thus be tempting to speculate that recombinant APC could be a novel treatment strategy to limit cancer progression. However, APC has however a short half-life, needs intravenous administration, and is associated with severe bleeding complications, complicating the potential clinical application of these findings. In contrast to APC, zymogen PC has a longer half-life and is associated with significantly less bleeding complications. To prove or refute the hypothesis that zymogen PC may be an attractive alternative treatment option for APC in cancer patients, we recently compared the effect of continuous overexpression of murine APC or zymogen PC in the liver by viral-mediated gene transfer in experimental metastasis. Interestingly, both APC and zymogen PC overexpression was highly effective in limiting experimental metastasis. An APC variant (APC-5A) with reduced anticoagulant but normal signaling properties did not limit experimental metastasis, whereas the protective effect of zymogen PC remained even in the absence of protease activated receptor-1 (PAR-1), which is the main mediator of APCs cytoprotective effect. Zymogen PC may thus be a novel therapeutic target to limit cancer progression. In conclusion, the natural anticoagulant APC pathway may play an important role in limiting cancer cell extravasation and interventions seeking to modulate the PC system may ultimately benefit the cancer patient. The challenge is however to confirm these findings in alternative preclinical cancer models and eventually to translate our findings into a clinical setting. Disclosures: No relevant conflicts of interest to declare.