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The generation of specific humoral and cellular immune responses plays a pivotal role in the development of effective vaccines against tumors. Especially the presence of antigen-specific, cytotoxic T cells influences the outcome of therapeutic cancer vaccinations. Different strategies, ranging from delivering antigen-encoding mRNAs to peptides or full antigens, are accessible but often suffer from insufficient immunogenicity and require immune-boosting adjuvants as well as carrier platforms to ensure stability and adequate retention. Here, we introduce a pH-responsive nanogel platform as a two-component antitumor vaccine that is safe for intravenous application and elicits robust immune responses

Clinical epigenetics 14, 29 (2022). doi:10.1186/s13148-022-01245-3, Published by BioMed Central, [Erscheinungsort nicht ermittelbar]

Abstract Regulatory T cells (Tregs) suppress immune responses and thus contribute to immune homeostasis. On the downside, Tregs also limit immune responses against tumors promoting the progression of cancer. Among the many mechanisms implied in Treg-mediated suppression, the inhibition of dendritic cells (DCs) has been shown to be central in peripheral tolerance induction as well as in cancers. We have shown previously that the maintenance of peripheral T cell tolerance critically depends on cognate interactions between Tregs and DCs and that the CTL priming by unsuppressed steady state DCs is mediated via CD70. Here, we have investigated whether the CD70/CD27 axis is also involved in Treg-mediated suppression of anti-tumor immunity. Using a mixed bone marrow chimeric mouse model in which we can deplete regulatory T cells in a temporally controlled fashion, we show that Treg-expressed CD27 prevents the breakdown of peripheral tolerance and limits anti-tumor immunity. Furthermore, ablation of Treg expressed CD27 acts synergistically with PD-1 checkpoint inhibition to improve CTL mediated immunity against a solid tumor. Our data thus identify Treg-expressed CD27 as a potential target in cancer immunotherapy. Key messages Treg expressed CD27 maintains steady state DC tolerogenic Treg expressed CD27 limits anti-tumor immunity Ablation of Treg expressed CD27 synergizes with PD-1 blockade to improve CTL mediated tumor control

Dendritic cells (DCs) are important inducers and regulators of T-cell responses. They are able to activate and modulate the differentiation of CD4+ and CD8+ T cells. In the skin, there are at least five phenotypically distinct DC subpopulations that can be distinguished by differential expression of the cell surface markers CD207, CD103, and CD11b. Previous studies have suggested that dermal CD11b−CD207+ conventional type 1 DCs are indispensable for the priming of a skin homing cytotoxic T-lymphocyte response. However, conventional type 1 DCs are also the only skin DC subset capable of cross-presenting exogenous antigens on major histocompatibility complex class I. Thus, it remained unclear whether for antigens that do not require cross-presentation, such as viruses that infect DCs, other DC subtypes in the skin can contribute to cytotoxic T-lymphocyte priming. To address this question, we used a transgenic mouse model that allows inducible expression and presentation of a model antigen on selected subsets of dermal DCs. We show that for antigens presented via the conventional major histocompatibility complex class I presentation pathway, CD207– dermal DCs are fully competent to prime a skin homing cytotoxic T-lymphocyte response that is capable of protection against a local virus challenge and gives rise to skin resident memory CD8+ T cells.

Introduction: Mutations (muts) in JAK2, MPL, and CALR are genetic hallmarks in myeloproliferative neoplasms such as myelofibrosis (MF). Prognostication in MF is predominantly based on clinical parameters according to the Dynamic International Prognostic Scoring System (DIPSS). However, gene mutations become increasingly important allowing for a more precised assessment of prognosis. For instance, CALR mutated MF is associated with favorable prognosis, while mutations in distinct high molecular-risk (HMR) genes are considered adverse. Our multicenter phase-Ib/II MPNSG-0212 trial (NCT01644110) investigating ruxolitinib plus pomalidomide in a total cohort of 92 patients with advanced MF and anemia provides an ideal basis for investigating the genomic landscape and molecular risk in a well-defined study population. Aims & Methods: To assess the genomic landscape in MF patients treated within the MPNSG-0212 trial and to correlate the results with clinical parameters and overall survival (OS). So far, targeted next generation sequencing (NGS) of 269 candidate genes was performed in peripheral blood or bone marrow from 81/92 patients using libraries prepared with SureSelectXT HS (Agilent, Santa Clara, USA). NGS was carried out on a NextSeq550 (Illumina, San Diego, USA). Results: At study entry, median age of the 81 patients was 71 years (range 52-86), median Hb 8.6 g/dL (range 5.4-11.7 g/dl); 30% of patients were RBC transfusion-dependent; 67% had primary MF (PMF) and 33% secondary MF (SMF), respectively. According to DIPSS, the vast majority of the patients were categorized as intermediate-2 (63%) or high-risk (26%) MF; 11% were low- and intermediate-1 risk patients. Overall, 315 muts were identified in 80/81 (99%) patients with a median of 3 muts/patient (range 0-9). Recurrent muts (≥5%) were identified in JAK2 (60%), ASXL1 (30%), SRSF2 (21%), CALR (20%; type-1: 75% [n=12], type-2 and non-type-1/2: 12.5% [n=2] each), MPL (19%), SF3B1 (19%), TET2 (16%), U2AF1 (15%), CBL and EZH2 (10% each), IDH2 and DNMT3A (7% each), PHF6, ZRSR2, and CUX1 (5% each). The majority of the patients (95%) was characterized by the presence of a driver mut in JAK2, CALR, or MPL; 4/81 patients (5%) were triple negative (Figure 1). JAK2mut was associated with TET2mut (p=.047), whereas muts in CALR and TET2 were mutually exclusive (p=.05). CALRmut patients had less co-muts than patients with JAK2/MPL muts (mean 2.5 vs. 4.1, p=.007) and were mutually exclusive with muts in the spliceosome regulating genes SRSF2, SF3B1, U2AF1, and ZRSR2 (p=.009). Compared to MF with mutated JAK2 or MPL, MF patients with mutated CALR had a longer median OS (not reached vs. 3.1 years; p=.04). With regard to high molecular risk (HMR) muts, n=56 were detected in 38 patients (47%), with 40% (15/38) of the patients harboring ≥2 HMR muts. The most commonly mutated HMR genes were ASXL1 (43%; 24/56), followed by SRSF2 (30%), EZH2 (14%), IDH2 (11%), and IDH1 (2%). MPLmut but not JAK2mut or CALRmut were significantly associated with HMR mut (p=.023). HMR mut patients harbored more co-muts than HMR wt patients (median 5 vs. 3; p Conclusions: Our NGS data underline the genomic complexity of advanced MF. CALR mutations were only found in 20% of the patients that were characterized by less co-mutations, mutual exclusivity with spliceosome mutations, and with more favorable outcome suggesting a distinct disease biology. Almost 50% of patients showed mutations in HMR genes which were associated with an inferior OS in univariate and multivariate analyses. §Frank Stegelmann and Konstanze Döhner contributed equally to this work. Figure 1 Figure 1. Disclosures Koschmieder: Shire: Honoraria, Other; Alexion: Other: Travel support; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Geron: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; AOP Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Baxalta: Membership on an entity's Board of Directors or advisory committees, Other; Abbvie: Other: Travel support; CTI: Membership on an entity's Board of Directors or advisory committees, Other; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Image Biosciences: Other: Travel support; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karthos: Other: Travel support. Heidel: Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CTI: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene/BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AOP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hochhaus: Bristol-Myers Squibb: Research Funding; Pfizer: Research Funding; Incyte: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Hebart: AbbVie: Honoraria; AstraZeneca: Honoraria; BMS: Honoraria; Janssen: Honoraria; Roche: Honoraria. Isfort: Alexion: Other: Travel reimbursement; Roche: Other: Travel reimbursement; Amgen: Other: Travel reimbursement; Mundipharma: Other: Travel reimbursement; Hexal: Other: Travel reimbursement; BMS: Honoraria; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel reimbursement; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel reimbursement. Reiter: AOP Orphan Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Deciphera: Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Blueprint Medicines: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding. Waller: Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; Mylan: Consultancy; Alvotech: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees; Lilly: Membership on an entity's Board of Directors or advisory committees, Other: travel support; Chugai: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees, Other: travel support; Amgen: Membership on an entity's Board of Directors or advisory committees; IPSEN: Other: travel grant. Scheid: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Goethert: Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Travel support; Incyte: Consultancy, Honoraria, Other: Travel support; zr pharma&: Honoraria; BMS: Consultancy, Honoraria, Other: Travel support; AOP Orphan Pharmaceuticals: Honoraria, Other: travel support; Proteros Biostructures: Consultancy. Schafhausen: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Swedish Orphan Biovitrum AB: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Blueprint Medicines: Membership on an entity's Board of Directors or advisory committees. Radsak: Otsuka: Consultancy, Honoraria; Abbvie: Other: e.g. travel support; Astellas: Other: e.g. travel support; TEVA: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: e.g. travel support; Daiichi Sankyo: Consultancy, Honoraria, Other: e.g. travel support; Celgene/BMS: Consultancy, Honoraria, Other: e.g. travel support; Amgen: Other: e.g. travel support; Takeda: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Corat: Consultancy, Honoraria; Cogent Biosciences: Consultancy, Honoraria; JAZZ: Other: e.g. travel support. Gattermann: Takeda: Research Funding; Novartis: Honoraria; Celgene: Honoraria. von Bubnoff: Novartis: Honoraria; Takeda: Honoraria. Brümmendorf: Bristol Myers: Research Funding; Janssen: Honoraria; Novartis: Honoraria, Patents & Royalties, Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Repeat Diagnostics: Research Funding; Takepart Media: Honoraria. Döhner: Celgene: Honoraria, Research Funding; Agios: Honoraria, Research Funding; GEMoaB: Honoraria; Astex Pharmaceuticals: Honoraria; Astellas: Honoraria, Research Funding; Oxford Biomedica: Honoraria; Novartis: Honoraria, Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; Janssen: Honoraria; Helsinn: Honoraria; Gilead: Honoraria; AstraZeneca: Honoraria; Abbvie: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; Berlin-Chemie: Honoraria; Roche: Honoraria; Pfizer: Research Funding. Griesshammer: Amgen: Consultancy, Honoraria; AOP Orphan: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; CTI: Consultancy, Honoraria; Shire: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria. Stegelmann: BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Döhner: Abbvie: Consultancy, Honoraria; Janssen: Honoraria, Other: Advisory Board; Jazz Roche: Consultancy, Honoraria; Daiichi Sankyo: Honoraria, Other: Advisory Board; Astellas: Research Funding; Celgene/BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Agios and Astex: Research Funding. OffLabel Disclosure: Pomalidomide was shown to be active in patients with myelofibrosis in particular in the treatment of anemia (Tefferi et al 2009, Begna et al 2011, Mesa et al 2010)

A lipid-protein autoimmunity target Several autoimmune diseases, including systemic lupus erythematosus and primary antiphospholipid syndrome, are characterized by the presence of antiphospholipid antibodies (aPLs). These molecules can activate the complement and coagulation cascades, which contributes to pathologies such as thrombosis, stroke, and pregnancy complications. Müller-Calleja et al. found that endothelial protein C receptor (EPCR) in complex with lysobisphosphatidic acid (LBPA) is the cell-surface target for aPL and mediates its internalization (see the Perspective by Kaplan). aPL binding to EPCR-LBPA resulted in the activation of tissue factor–mediated coagulation and interferon-α production by dendritic cells. Interferon-α, in turn, fueled the expansion of B1a cells, which secrete aPLs. The specific blockade of this target in mice inhibited the development of aPL autoimmunity, offering hope for future therapies for these conditions. Science , this issue p. eaay1833 ; see also p. 1100

ERK3 is a ubiquitously expressed member of the atypical mitogen activated protein kinases (MAPKs) and the physiological significance of its short half-life remains unclear. By employing gastrointestinal 3D organoids, we detect that ERK3 protein levels steadily decrease during epithelial differentiation. ERK3 is not required for 3D growth of human gastric epithelium. However, ERK3 is stabilized and activated in tumorigenic cells, but deteriorates over time in primary cells in response to lipopolysaccharide (LPS). ERK3 is necessary for production of several cellular factors including interleukin-8 (IL-8), in both, normal and tumorigenic cells. Particularly, ERK3 is critical for AP-1 signaling through its interaction and regulation of c-Jun protein. The secretome of ERK3-deficient cells is defective in chemotaxis of neutrophils and monocytes both in vitro and in vivo. Further, knockdown of ERK3 reduces metastatic potential of invasive breast cancer cells. We unveil an ERK3-mediated regulation of IL-8 and epithelial secretome for chemotaxis.

Cells 9(9), 2034 (1-19) (2020). doi:10.3390/cells9092034, Hybrid nanoparticles from lipidic and polymeric components were assembled to serve as vehicles for the transfection of messenger RNA (mRNA) using different portions of the cationic lipid DOTAP (1,2-Dioleoyl-3-trimethylammonium-propane) and the cationic biopolymer protamine as model systems. Two different sequential assembly approaches in comparison with a direct single-step protocol were applied, and molecular organization in correlation with biological activity of the resulting nanoparticle systems was investigated. Differences in the structure of the nanoparticles were revealed by thorough physicochemical characterization including small angle neutron scattering (SANS), small angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM). All hybrid systems, combining lipid and polymer, displayed significantly increased transfection in comparison to lipid/mRNA and polymer/mRNA particles alone. For the hybrid nanoparticles, characteristic differences regarding the internal organization, release characteristics, and activity were determined depending on the assembly route. The systems with the highest transfection efficacy were characterized by a heterogenous internal organization, accompanied by facilitated release. Such a system could be best obtained by the single step protocol, starting with a lipid and polymer mixture for nanoparticle formation., Published by MDPI, Basel

Patients undergoing allogeneic hematopoietic stem cell transplantation have a high morbidity and mortality, especially after admission to intensive care unit (ICU) during peri-transplant period. The objective of this study was to identify new clinical and biological parameters and validate prognostic scores associated with ICU, short-and long-term survival. Significant differences between ICU survivors and ICU non-survivors for the clinical parameters invasive mechanical ventilation, urine output, heart rate, mean arterial pressure, and amount of vasopressors have been measured. Among prognostic scores (SOFA, SAPSII, PICAT, APACHE II, APACHE IV) assessing severity of disease and predicting outcome of critically ill patients on ICU, the APACHE II score has shown most significant difference (p = 0.002) and the highest discriminative power (area under the ROC curve (AUC) 0.74). An elevated level of lactate at day of admission was associated with poor survival on ICU and the most significant independent parameter (p

Dyskeratosis congenita (DKC) is a paradigmatic telomere disorder characterized by substantial and premature telomere shortening, bone marrow failure, and a dramatically increased risk of developing myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). DKC can occur as a late-onset, so-called cryptic form, with first manifestation in adults. Somatic MDS-related mutations are found in up to 35% of patients with acquired aplastic anemia (AA), especially in patients with short telomeres. The aim of our study was to investigate whether cryptic DKC is associated with an increased incidence of MDS-related somatic mutations, thereby linking the accelerated telomere shortening with the increased risk of MDS/AML. Samples from 15 adult patients (median age: 42 years, range: 23-60 years) with molecularly confirmed cryptic DKC were screened using next-generation gene panel sequencing to detect MDS-related somatic variants. Only one of the 15 patients (7%) demonstrated a clinically relevant MDS-related somatic variant. This incidence was dramatically lower than formerly described in acquired AA. Based on our data, we conclude that clonal evolution of subclones carrying MDS-related mutations is not the predominant mechanism for MDS/AML initiation in adult cryptic DKC patients.

Triggering receptor expressed on myeloid cells (TREM)-1 on polymorphonuclear neutrophils (PMN) regulates innate immune activation in infectious and non-infectious conditions. TREM-1 ligation activates phosphatidyl-inositol 3 kinase (PI3K) triggering all neutrophil effector functions. As idelalisib is a PI3K inhibitor in clinical use for the treatment of non-Hodgkin lymphomas, we asked whether this inhibitor affects PMN functionalities. We analyzed PMNs from healthy donors or lymphoma patients for oxidative burst, phagocytosis, activation markers and IL-8 release upon TREM-1 or TLR ligation ex vivo. In addition, we performed western blot analyses to characterize the signaling events inhibited by idelalisib and other PI3K inhibitors. Upon TREM-1 ligation, the oxidative burst, degranulation, L-selectin shedding and cytokine release were all strongly reduced in the presence of idelalisib along impaired phosphorylation of P38, AKT and ERK by western blot analyses. In line with this, PMNs from patients receiving idelalisib also displayed an impaired TREM-1 mediated PMN activation ex vivo. In conclusion, PI3K inhibitors might cause a neutropenia-like susceptibility to infections in patients by leading to impaired PMN functionality. This should be considered when evaluating patients for infections treated with such inhibitors in daily clinical routine.

Introduction: Telomere biology disorders (TBD) are caused by mutations affecting proper telomere maintenance resulting in premature telomere shortening. Telomere length (TL) assessment is currently being used for screening and diagnosis of TBD of which Dyskeratosis congenita (DKC) is the most prominent TBD subtype typically found in children and adolescents. In adults, TBDs are characterized by a broad spectrum of more "cryptic" diverging mono- or oligosymptomatic clinical manifestations such as bone marrow failure (BMF), hepatopathy or interstitial lung disease (ILD). However, despite growing general clinical awareness and exertion of improved TL screening strategies, insufficient data are available about the clinical course of adult, late-onset TBDs. Here, we present a series of 41 consecutive adult TBD cases from 2014 to 2021 identified through the Aachen Telomeropathy registry. Methods and Patients: Median follow-up of the cohort was 2.0 (range 0-6.2) years. In 39/41 patients TBD diagnosis was established based on coexistence of the following three criteria: 1.) Identification of pathogenic variant in a known TBD-related gene via next-generation panel sequencing (NGS) or sequential whole exome sequencing (WES). 2.) The presence of prematurely shortened TL below the 1% percentile (39/41) or 5% percentile (2/41) in the lymphocyte gate detected by flow-FISH and 3.) the presence of BMF or ILD as predominant clinical manifestation. In 2 out of 41 cases, WES did not identify a definitive pathogenic variant. Here, diagnosis of TBD was established due to short telomere below the 1% percentile, BMF and the presence of typical DKC stigmata, other TBD symptoms and a positive family history. Results: Mean age of our cohort was 35.9 ± 17.6 years. 49% (n=20) of patients were females. Results of the genetic screening revealed heterozygous pathogenic variants in TERC (n=14) and TERT (n=11) as the most frequent variants, followed by RTEL1 (n=6), TIN2 (n=1), CTC1 (n=1) and DKC1 (n=1). Homozygous or compound heterozygous pathogenic variants were found for CTC1 (n=2), NHP2 (n=2) or TCAB1 (n=1). 46% (n=19) of patients had a positive family history. BMF was the most frequent symptom with 93% (n=38) presenting with leukopenia, 78% (n=32) with anemia and 76% (n=31) with thrombocytopenia. ILD was suspected/confirmed clinically in 44% (n=18), hepatopathies in 29% (n=12) and cancer in 12% of the patients in past medical history (n=5, liposarcoma, breast cancer, Hodgkin lymphoma, diffuse large B-cell lymphoma, endometrial cancer). Symptoms of the typical DKC triad (leukoplakia, nail dystrophy, abnormal skin pigmentation) were observed in 41% (n=17). Of those, 76% (13/17) presented with only one or two clinical signs. Based on past medical history, the onset of first TBD manifestation was observed at a mean age of 26.9 ± 18.3 years. Time from first symptom observed to the diagnosis of TBD was 8.2 ± 9.5 years. 22% (n=9) patients died during follow-up with mean time of 11.7 ± 10.1 years from first manifestation of TBD to death. Regarding treatment, 39% (n=16) were listed for allogeneic stem cell transplantation (allo Tx), but only 38% (6/16) of these eventually received allo Tx. Immunosuppressive therapy with ATG and CSA was carried out in 12% (n=5) of the patients with no patient responding to treatment. Eltrombopag was given in 5% of cases (n=2) without response. 15% (n=6) received androgen treatment with danazol as the most frequently used drug in five of the six reported cases. All patients showed a response at least in one hematological lineage. Conclusions: Our data support the notion that despite the recent progress in screening and genetic diagnostics, late-onset TBD is still frequently underdiagnosed with several years from first manifestation of disease to diagnosis. Implementation of routine screening for TBD might improve the rate of correct TBD diagnosis and could help to avoid ineffective treatments. Disclosures Beier: Pfizer: Membership on an entity's Board of Directors or advisory committees; Jazz: Other: Travel reembursement; Alexion: Speakers Bureau. Roeth: Novartis: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Kira: Consultancy, Honoraria; Bioverativ, a Sanofi company: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Apellis Pharmaceuticals: Consultancy, Honoraria; Alexion Pharmaceuticals Inc.: Consultancy, Honoraria. Platzbecker: AbbVie: Honoraria; Novartis: Honoraria; Celgene/BMS: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Geron: Honoraria. Radsak: Novartis: Consultancy, Honoraria, Other: e.g. travel support; JAZZ: Other: e.g. travel support; Takeda: Consultancy, Honoraria; Celgene/BMS: Consultancy, Honoraria, Other: e.g. travel support; Daiichi Sankyo: Consultancy, Honoraria, Other: e.g. travel support; Astellas: Other: e.g. travel support; Incyte: Consultancy, Honoraria; Corat: Consultancy, Honoraria; Cogent Biosciences: Consultancy, Honoraria; TEVA: Consultancy, Honoraria; Otsuka: Consultancy, Honoraria; Amgen: Other: e.g. travel support; Abbvie: Other: e.g. travel support. Schafhausen: Blueprint Medicines: Membership on an entity's Board of Directors or advisory committees; Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Swedish Orphan Biovitrum AB: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Corbacioglu: Gentium/Jazz Pharmaceuticals: Consultancy, Honoraria. Heuser: AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria; BergenBio: Research Funding; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer Pharma AG: Research Funding; Astellas: Research Funding; Karyopharm: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolremo: Membership on an entity's Board of Directors or advisory committees. Koschmieder: Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Karthos: Other: Travel support; Shire: Honoraria, Other; CTI: Membership on an entity's Board of Directors or advisory committees, Other; Sanofi: Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Geron: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Alexion: Other: Travel support; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Baxalta: Membership on an entity's Board of Directors or advisory committees, Other; Abbvie: Other: Travel support; Image Biosciences: Other: Travel support; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; AOP Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding. Panse: Blueprint Medicines: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Chugai: Speakers Bureau; Pfizer: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Alexion: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Grunenthal: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Apellis Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Isfort: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel reimbursement; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel reimbursement; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Hexal: Other: Travel reimbursement; Mundipharma: Other: Travel reimbursement; Amgen: Other: Travel reimbursement; Roche: Other: Travel reimbursement; Alexion: Other: Travel reimbursement. Brummendorf: Bristol Myers: Research Funding; Janssen: Honoraria; Novartis: Honoraria, Patents & Royalties, Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Repeat Diagnostics: Research Funding; Takepart Media: Honoraria.

Myelodysplastic syndromes are characterised by ineffective erythropoiesis. Luspatercept (ACE-536) is a novel fusion protein that blocks transforming growth factor beta (TGF β) superfamily inhibitors of erythropoiesis, giving rise to a promising new investigative therapy. We aimed to assess the safety and efficacy of luspatercept in patients with anaemia due to lower-risk myelodysplastic syndromes.In this phase 2, multicentre, open-label, dose-finding study (PACE-MDS), with long-term extension, eligible patients were aged 18 years or older, had International Prognostic Scoring System-defined low or intermediate 1 risk myelodysplastic syndromes or non-proliferative chronic myelomonocytic leukaemia (white blood cell count13 000/μL), and had anaemia with or without red blood cell transfusion support. Enrolled patients were classified as having low transfusion burden, defined as requiring less than 4 red blood cell units in the 8 weeks before treatment (and baseline haemoglobin10 g/dL), or high transfusion burden, defined as requiring 4 or more red blood cell units in the 8 weeks before treatment. Patients received luspatercept subcutaneously once every 21 days at dose concentrations ranging from 0·125 mg/kg to 1·75 mg/kg bodyweight for five doses (over a maximum of 12 weeks). Patients in the expansion cohort were treated with 1·0 mg/kg luspatercept; dose titration up to 1·75 mg/kg was allowed, and patients could be treated with luspatercept for a maximum of 5 years. Patients in the base study were assessed for response and safety after 12 weeks in order to be considered for enrolment into the extension study. The primary endpoint was the proportion of patients achieving modified International Working Group-defined haematological improvement-erythroid (HI-E), defined as a haemoglobin concentration increase of 1·5 g/dL or higher from baseline for 14 days or longer in low transfusion burden patients, and a reduction in red blood cell transfusion of 4 or more red blood cell units or a 50% or higher reduction in red blood cell units over 8 weeks versus pre-treatment transfusion burden in high transfusion burden patients. Patient data were subcategorised by: luspatercept dose concentrations (0·125-0·5 mg/kg vs 0·75-1·75 mg/kg); pre-study transfusion burden (high transfusion burden vs low transfusion burden, defined as ≥4 vs4 red blood cell units per 8 weeks); pre-study serum erythropoietin concentration (200 IU/L, 200-500 IU/L, and500 IU/L); presence of 15% or more ring sideroblasts; and presence of SF3B1 mutations. Efficacy analyses were carried out on the efficacy evaluable and intention-to-treat populations. This trial is currently ongoing. This study is registered with ClinicalTrials.gov, numbers NCT01749514 and NCT02268383.Between Jan 21, 2013, and Feb 12, 2015, 58 patients with myelodysplastic syndromes were enrolled in the 12 week base study at nine treatment centres in Germany; 27 patients were enrolled in the dose-escalation cohorts (0·125-1·75 mg/kg) and 31 patients in the expansion cohort (1·0-1·75 mg/kg). 32 (63% [95% CI 48-76]) of 51 patients receiving higher dose luspatercept concentrations (0·75-1·75 mg/kg) achieved HI-E versus two (22% [95% CI 3-60]) of nine receiving lower dose concentrations (0·125-0·5 mg/kg). Three treatment-related grade 3 adverse events occurred in one patient each: myalgia (one [2%]), increased blast cell count (one [2%]), and general physical health deterioration (one [2%]). Two of these treatment-related grade 3 adverse events were reversible serious grade 3 adverse events: one patient (2%) had myalgia and one patient (2%) had general physical health deterioration.Luspatercept was well tolerated and effective for the treatment of anaemia in lower-risk myelodysplastic syndromes and so could therefore provide a novel therapeutic approach for the treatment of anaemia associated with lower-risk myelodysplastic syndromes; further studies are ongoing.Acceleron Pharma.

Background: Luspatercept, a first-in-class erythroid maturation agent, has been investigated in patients with LR-MDS and ring sideroblasts (RS) (MEDALIST; Fenaux and Platzbecker NEJM 2020) and in an ongoing Phase 3 trial regardless of RS status (COMMANDS, NCT03682536 ). The previously reported Phase 2 trial of luspatercept (Platzbecker Lanc Onc 2017) includes subtypes of LR-MDS with and without RS, regardless of prior ESA exposure, and various EPO levels. Aims: Evaluate the long-term safety and efficacy of luspatercept in LR-MDS. Methods: Patients were IPSS low/int-1, age ≥ 18 years, Hgb NCT01749514 ; NCT02268383 ). Results: As of 13July2019, 115 patients were enrolled, of whom 108 were treated with ≥0.75 mg/kg. 44/108 (41%) were non-RS; 47/108 (44%) had prior ESA; 45/108 (42%) had baseline transfusion burden of ≥4U RBC/8 weeks. Median duration of treatment (n=108) was 10.4 (0.7-57.3) months. IWG HI-E RR was 54% (58/108) overall; 36% (16/44) in non-RS, 68% (42/62) in RS+ (2 patients had unknown RS status); 53% (25/47) prior ESA, 54% (33/61) in ESA-naive; 54% (34/63) in 2 patients) were fatigue, headache, hypertension, arthralgia, bone pain, diarrhea, injection site erythema, myalgia, and peripheral edema. Conclusions: Consistent with previous reports, data from the long-term Phase 2 study of luspatercept in LR-MDS continues to show efficacy in a variety of subtypes and safety similar to previous and ongoing studies.

Background and Aims: In immunosuppressed individuals Aspergillus (A.) fumigatus is a frequent cause of invasive pulmonary aspergillosis (IPA) which is highly associated with relevant morbidity and mortality. Moreover, it often occurs in patients suffering from leukocyte-adhesion deficiency type 1 (LAD1) which is triggered by a functional loss of CD18 in ß2 integrin receptors as these receptors consist of an alpha subunit (CD11a-CD11d) and CD18 as the common beta subunit. ß2 integrin receptors are differentially expressed by leukocytes, and are required for cell-cell interaction, transendothelial migration, uptake of opsonized pathogens, and cell signaling processes. Here, we asked for the importance of CD11b/CD18 also termed MAC-1 which is required for phagocytosis of opsonized A. fumigatus conidia by polymorphonuclear neutrophils (PMN) for control of pulmonary A. fumigatus infection. Methods: We used a murine IPA model (C57BL/6) and challenged CD11b deficient (CD11b-/-) or wild type (WT) mice with A. fumigatus conidia intratracheally. Afterwards, some mice were sacrificed 24h after infection. In these mice PMN recruitment and cytokine patterns were examined by analyzing bronchoalveolar lavage fluid (BALF) and peripheral blood (PB) using flow cytometry, cytospin analysis, and cytometric bead array. Additionally, pulmonary fungal clearance and inflammation in murine lungs were analyzed by fungal culture assays and histopathologic examination using a scoring system. Furthermore, survival was studied with neutropenic animals serving as positive controls. To determine PMNs phagocytic activity and fungal killing capacity ex vivo, PMN were purified from bone marrow of CD11b-/- or WT mice by magnetic cell sorting using Ly6G specific antibodies. Afterwards, isolated PMN were stimulated with pacific blue-labeled tomato red-fluorescent modified A. fumigatus conidia and analyzed by flow cytometry. Results: We found that lung homogenates from CD11b-/- mice obtained 24h after infection showed an enhanced fungal burden as compared to lungs from WT mice. In contrast, lung tissue from infected CD11b-/- mice displayed impaired pulmonary inflammation as assessed by Hematoxilin-Eosin (HE) staining. Furthermore, the number of mucus-producing cells in bronchi of A. fumigatus infected CD11b-/- mice was decreased compared to cells in bronchi of WT mice. However, we observed markedly higher numbers of PMN in BALF of infected CD11b-/- mice compared to corresponding WT mice samples. In contrast, BALF derived from infected CD11b-/- mice contained lower levels of three different proinflammatory cytokines (TNF-α, IL-1α, IL-1β) compared to BALF from WT mice while levels of other cytokines and chemokines (IL-5, IL-6, IL-10, GM-CSF, CXCL1, CCL2) were comparable. In contrast, we measured higher levels of the chemokine CCL5 known as a relevant chemoattractant in innate and adaptive immune cells in BALF obtained from CD11b-/- mice. Interestingly, numbers of PMN, lymphocytes, and monocytes in the peripheral blood of A. fumigatus infected mice did not differ in a genotype-dependent manner. However, CD11b-/- mice PMN showed lower phagocytic activity than WT PMN, indicating an impaired capability to clear A. fumigatus. Nevertheless, CD11b-/- mice were finally characterized by similar long-term survival as WT mice after IPA induction while the PMN-depleted control mice died as expected. Conclusions: Our study demonstrates, that CD11b deficiency on myeloid cells affects the early course of IPA. This may be due to the importance of MAC-1 for PMN effector functions, and their interplay with DC and other leukocytes. Further work is necessary to elucidate the long-term course of IPA in CD11b-/- mice with regard to the interplay of PMN with dendritic cells, the efficacy of adaptive immune responses, and the potential pulmonary overexpression of CCL5. Beyond patients with LAD1 syndrome, we suggest our findings as being clinically relevant in other immunocompromised patients suffering from severe opportunistic infections. Disclosures Radsak: Celgene: Honoraria, Other: Travel grant; Jazz Pharmaceuticals: Other: Travel grant; TEVA: Consultancy; Gilead: Other: Travel grant; Takeda: Consultancy; Novartis: Consultancy, Honoraria; Daiichi Sankyo: Honoraria, Other: Travel grant.

There is a growing body of evidence for immunomodulatory side effects of antifungal agents on different immune cells, e.g., T cells. Therefore, the aim of our study was to clarify these interactions with regard to the effector functions of polymorphonuclear neutrophils (PMN). Human PMN were preincubated with fluconazole (FLC), voriconazole (VRC), posaconazole (POS), isavuconazole (ISA), caspofungin (CAS), micafungin (MFG), conventional amphotericin B (AMB), and liposomal amphotericin B (LAMB). PMN then were analyzed by flow cytometry for activation, degranulation, and phagocytosis and by dichlorofluorescein assay to detect reactive oxygen species (ROS). Additionally, interleukin-8 (IL-8) release was measured by enzyme-linked immunosorbent assay. POS led to enhanced activation, degranulation, and generation of ROS, whereas IL-8 release was reduced. In contrast, ISA-pretreated PMN showed decreased activation signaling, impaired degranulation, and lower generation of ROS. MFG caused enhanced expression of activation markers but impaired degranulation, phagocytosis, generation of ROS, and IL-8 release. CAS showed increased phagocytosis, whereas degranulation and generation of ROS were reduced. AMB led to activation of almost all effector functions besides impaired phagocytosis, whereas LAMB did not alter any effector functions. Independent from class, antifungal agents show variable influence on neutrophil effector functions in vitro. Whether this is clinically relevant needs to be clarified.

Background Patients with relapsed or refractory FLT3 internal tandem duplication (FLT3-ITD)-positive acute myeloid leukaemia have a poor prognosis, including high frequency of relapse, poorer response to salvage therapy, and shorter overall survival than those with FLT3 wild-type disease. We aimed to assess whether single-agent quizartinib, an oral, highly potent and selective type II FLT3 inhibitor, improves overall survival versus salvage chemotherapy. Methods QuANTUM-R is a randomised, controlled, phase 3 trial done at 152 hospitals and cancer centres in 19 countries. Eligible patients aged 18 years or older with ECOG performance status 0-2 with relapsed or refractory (duration of first composite complete remission 30 days if suspected to be a treatment-related event) for quizartinib (241 patients) and chemotherapy (94 patients) were sepsis or septic shock (46 patients [19%] for quizartinib vs 18 [19%] for chemotherapy), pneumonia (29 [12%] vs eight [9%]), and hypokalaemia (28 [12%] vs eight [9%]). The most frequent treatment-related serious adverse events were febrile neutropenia (18 patients [7%]), sepsis or septic shock (11 [5%]), QT prolongation (five [2%]), and nausea (five [2%]) in the quizartinib group, and febrile neutropenia (five [5%]), sepsis or septic shock (four [4%]), pneumonia (two [2%]), and pyrexia (two [2%]) in the chemotherapy group. Grade 3 QT prolongation in the quizartinib group was uncommon (eight [3%] by central reading, ten [4%] by investigator report); no grade 4 events occurred. There were 80 (33%) treatment-emergent deaths in the quizartinib group (31 [13%] of which were due to adverse events) and 16 (17%) in the chemotherapy group (nine [10%] of which were due to adverse events). Interpretation Treatment with quizartinib had a survival benefit versus salvage chemotherapy and had a manageable safety profile in patients with rapidly proliferative disease and very poor prognosis. Quizartinib could be considered a new standard of care. Given that there are only a few available treatment options, this study highlights the value of targeting the FLT3-ITD driver mutation with a highly potent and selective FLT3 inhibitor.

Biomaterials 192, 612 - 620 (2019). doi:10.1016/j.biomaterials.2018.10.020, mRNA pharmaceuticals represent a new class of therapeutics, with applications, in cancer vaccination, tumour therapy and protein substitution. Formulations are required to deliver messenger RNA (mRNA) to the target sites where induction of genetic transfection following receptor mediated cell uptake & translation is required.In the current study, the cationic polysaccharide diethylaminoethylen (DEAE) – Dextran was selected as a model system carrier for the investigation of polyplex nanoparticle formation together with mRNA as a function of the molar ratio of the components. The structure of the mRNA/Dextran colloids was investigated as a function of the polymer-to-mRNA ratio and correlated with the biological activity determined by cellular transfection with luciferase coding mRNA. Dynamic light scattering (DLS), small angle x-ray scattering (SAXS), and small angle neutron scattering (SANS) with deuterium contrast variation were used to achieve structural insight into the systems. Similarly to previously investigated lipid based systems, colloidally stable particles with confined size were obtained with either excess of positive or negative charge. Highest activity was obtained with positive charge excess. From the scattering experiments information on the internal organization inside the polymer/mRNA systems was derived. Indication for the presence of structural elements in the length scale of ten to 20 nm were found in the excess of dextran, which could be due to either excess or particulate polymer. Information on the molecular organization of the mRNA nanoparticle products may provide a valuable basis for defining critical quality attributes of drug products for pharmaceutical application., Published by Elsevier Science, Amsterdam [u.a.]

Transcutaneous immunization (TCI) is a novel vaccination strategy that utilizes skin-associated lymphatic tissue to induce immune responses. Employing T-cell epitopes and the TLR7 agonist imiquimod onto intact skin mounts strong primary, but limited memory CTL responses. To overcome this limitation, we developed a novel imiquimod-containing vaccination platform (IMI-Sol) rendering superior primary CD8+ and CD4+ T-cell responses. However, it has been unclear whether IMI-Sol per se is restricted in terms of memory formation and tumor protection. In our present work, we demonstrate that the combined administration of IMI-Sol and CD40 ligation unleashes fullblown specific T-cell responses in the priming and memory phase, strongly enhancing antitumor protection in mice. Interestingly, these effects were entirely CD4+ T cell independent, bypassing the necessity of helper T cells. Moreover, blockade of CD70 in vivo abrogated the boosting effect of CD40 ligation, indicating that the adjuvant effect of CD40 in TCI is mediated via CD70 on professional APCs. Furthermore, this work highlights the so far underappreciated importance of the CD70/CD27 interaction as a promising adjuvant target in TCI. Summing up, we demonstrate that the novel formulation IMI-Sol represents a powerful vaccination platform when applied in combination with sufficient adjuvant thereby overcoming current limitations of TCI.

Imiquimod, a toll-like receptor 7 (TLR7) agonist, is an active pharmaceutical ingredient (API) established for the topical treatment of several dermal cancerous and precancerous skin lesions. Within this work, the immunostimulatory effect of imiquimod is further exploited in a transcutaneous immunization (TCI) approach based on a solid nanoemulsion (SN) formulation. SN contains a combination of imiquimod with the model peptide antigen SIINFEKL as a novel approach to omit needle and syringe and optimize dermal antigen administration. Excipients including sucrose fatty acid esters and the pharmaceutically acceptable oils MCT (middle chain triglycerides), avocado oil, jojoba wax and squalene are high pressure homogenized together with the antigen SIINFEKL. Freeze drying was performed to eliminate water and to achieve spreadable properties of the formulation for dermal administration. The influence of the different oil components was assessed regarding in vitro drug permeation in a Franz diffusion cell model using a murine skin setup. In vivo performance in terms of cytotoxic T-cell response was assessed in a C57BL/6 mouse model. Whereas Aldara® cream contains imiquimod in a dissolved state, the SN formulations carry the active in a suspended state. This resulted in a reduction of imiquimod permeation across murine skin from the SN when compared to Aldara® cream. In spite of this permeation rate reduction, each SN induced an in vivo immune response by specific T-cell lysis. A stabilized solid nanosuspension containing squalene/tocopherol exhibited a significantly higher performance (p⩽0.05) in comparison with Aldara® cream. MCT based SN exerted an in vivo effect comparable to Aldara®. In conclusion, anhydrous highly dispersed vehicles containing imiquimod in a submicron particle size distribution can represent promising formulations for TCI. The choice of the oil component has a strong influence on SN performance, independent of in vitro drug permeation.

Undifferentiated pleomorphic sarcoma not otherwise specified belongs to the heterogeneous group of soft tissue tumors. It is preferentially located in the upper and lower extremities of the body, and surgical resection remains the only curative treatment. Preclinical animal models are crucial to improve the development of novel chemotherapeutic agents for the treatment of undifferentiated pleomorphic sarcoma. However, this approach has been hampered by the lack of reproducible animal models. The present study established two xenograft animal models generated from stable non-clonal cell cultures, and investigated the difference in chemotherapeutic effects on tumor growth between undifferentiated pleomorphic sarcoma in vivo and in vitro. The cell cultures were generated from freshly isolated tumor tissues of two patients with undifferentiated pleomorphic sarcoma. For the in vivo analysis, these cells were injected subcutaneously into immunodeficient mice. The mice were monitored for tumor appearance and treated with the most common or innovative chemotherapeutic agents available to date. Furthermore, the same drugs were administered to in vitro cell cultures. The most effective tumor growth inhibition in vitro was observed with doxorubicin and the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA), also known as vorinostat. In the in vivo xenograft mouse model, the combination of doxorubicin and the tyrosine kinase inhibitor pazopanib induced a significant tumor reduction. By contrast, treatment with vorinostat did not reduce the tumor growth. Taken together, the results obtained from drug testing in vitro differed significantly from the in vivo results. Therefore, the novel and reproducible xenograft animal model established in the present study demonstrated that in vivo models are required to test potential chemotherapeutic agents for the treatment of undifferentiated pleomorphic sarcoma prior to clinical use, since animal models are more similar to humans, compared with in vitro cell cultures.

The formation of monocyte-platelet aggregates and neutrophil-platelet aggregates (MPA and NPA, respectively) is influenced by inflammation, but also might contribute to an exacerbation of inflammatory responses in atherosclerotic plaque. The purpose of this study was to analyze MPA and NPA proportions in regard to different stages of peripheral arterial disease (PAD). Forty-five patients with intermittent claudication (IC) (3 groups: Rutherford (R)-1, R-2, and R-3; each n = 15), 20 patients with critical limb ischemia (CLI) (Rutherford 5 (40%) and 6 (60%)), and 20 healthy controls were studied. Analyses of monocyte (Mon) subpopulations (CD14++CD16- (classical) Mon1, CD14++CD16+ (intermediate) Mon2, CD14+CD16++ (non-classical) Mon3), MPA, and NPA was performed from whole blood by flow cytometry. Controls showed an increased proportion of the Mon1 subpopulation (p < 0.001), whereas CLI patients showed a significant increase of the Mon2 subpopulation compared to controls, R-1, or R-2 patients (p < 0.0001). For the Mon3 subpopulation, CLI and R-3 patients showed an increased proportion (p < 0.05). MPA formation with the proinflammatory Mon2 and Mon3 subpopulations was increased in CLI patients (both p < 0.01). Similarly, NPA was significantly increased in CLI patients (p < 0.05). Serological markers of inflammation and procoagulation (fibrinogen [r = 0.459, p < 0.001], soluble triggering receptor expressed on myeloid cells (sTREM-1) [r = 0.237, p < 0.05] and P-Selectin [r = 0.225, p < 0.05]) correlated directly with MPA formation on the Mon2 subpopulation. We found an association of inflammatory and procoagulatory markers with increased formation of MPA on the Mon2 subpopulation. Since R-3 patients also had significantly increased MPA, one can speculate that the inflammatory burden might promote an aggravation of the disease.

Neutrophil extracellular traps (NETs) are formed by polymorphonuclear neutrophils (PMN) and contribute to the innate host defense by binding and killing bacterial and fungal pathogens. Because NET formation depends on histone hypercitrullination by peptidylarginine deiminase 4 (PAD4), we used PAD4 gene deficient (Pad4-/-) mice in a mouse model of invasive pulmonary aspergillosis (IPA) to address the contribution of NETs to the innate host defense in vivo. After the induction (24 h) of IPA by i.t. infection with Aspergillus fumigatus conidia, Pad4-/- mice revealed lower fungal burden in the lungs, accompanied by less acute lung injury, TNFα and citH3 compared to wildtype controls. These findings suggest that release of NETs contributes to tissue damage and limits control of fungal outgrowth. Thus inhibition of NETosis might be a useful strategy to maintain neutrophil function and avoid lung damage in patients suffering from IPA, especially in those suffering from preexisting pulmonary disease.

Background: Anemia remains one cardinal symptom associated with reduced quality of life (QoL) in patients (pts) with myelofibrosis (MF) which is normally not being addressed by ruxolitinib (RUX). In our previous MPNSG-0109 trial, single-agent pomalidomide (POM) improved cytopenia in 14% (POM 0.5 mg QD) and 29% (POM 2.0 mg QD) of MF pts, respectively. In the MPNSG-0212 study, we sought to investigate the potential synergism of RUX plus POM to improve anemia and QoL in MF pts. Study Design: MPNSG-0212 is an ongoing multicenter, open-label, single-arm phase-Ib/II trial with a target population of 90 pts following a two-stage design (NCT01644110). Pts 1-40 in cohort 1 (co1) were treated with RUX (10 mg BID) plus low-dose POM (0.5 mg QD), while pts 41-90 in cohort 2 (co2) receive a step-wise dose increase of POM from 0.5 mg to 1 mg and 2 mg QD after 3 and 6 28-day-cycles, respectively. Primary endpoints are safety of the combination therapy, anemia response after 12 cycles (according to IWG-MRT and RBC transfusion independence [RBC-TI] criteria), and clinical benefit (CB) defined as stable disease plus i) hemoglobin (Hb) increase ≥1 g/dL in pts with RBC-TI or ii) doubling of RBC transfusion intervals and/or iii) significant (>25%) improvement of QoL as measured by the MPN-SAF questionnaire. Main inclusion criterion is MF with anemia (Hb Results: At data cut-off (31-May-2019), 79 pts were included. Data from 67 pts were available for evaluation (co1, n=40; co2, n=27). Baseline characteristics of the pts were as follows: median age 72 years (range 49-84), prior treatment in 53% (RUX in 22%, POM in 4%), median Hb level at study start 8.6 g/dL (range 5.4-11.7), RBC-TD in 28%, median spleen diameter measured by ultrasound 17.7 cm (range 12-36), presence of constitutional symptoms in 76%, and 91% intermediate-2 (61%) or high-risk (30%) pts according to DIPSS; 55% of pts in co1 had ≥1 high molecular risk mutation (ASXL1, SRSF2, EZH2, and/or IDH1/2). Median number of cycles until data cut-off was 12 (range 2-63) in co1 and 11 (range 2-21) in co2. In total, 502 adverse events (AE) mainly grade 1/2 were recorded: AE grade 1/2 in >20% of pts were fatigue (in 27% of pts), dyspnea (24%), diarrhea (22%), and muscle cramps (21%); AE grade ≥3 in >3% of pts was Hb decrease in the first weeks of treatment occurring in 25% of pts. In total, 87 serious AE (SAE), were recorded: most common SAE (in ≥3 pts) were pneumonia (in 15% of pts), leukemic transformation (9%), worsening of general condition (6%), CNS ischemia, and sepsis (4% each); 7 SAE (in 10% of pts) were grade 5. Number or severity of (S)AE was not increased in co2. Treatment interruptions of RUX and/or POM were necessary in 11 pts (27%) of co1 and 3 pts (11%) of co2; 2 pts stopped treatment permanently due to hematotoxicity. Increase of the POM dose to 1 mg and 2 mg QD was feasible in the majority of pts after 3 and 6 cycles, respectively. In co1, 18/40 pts (45%) continued treatment beyond cycle 12 because of an objective anemia response (7/40, 18%: clinical improvement [CI, Hb increase ≥2 g/dL] n=5, partial remission and RBC-TI n=1 each) or CB (11/40, 27%): Hb increase ≥1 g/dL and/or doubling of RBC transfusion intervals (n=4) or improvement of QoL according to MPN-SAF (n=7). In co2, 17/27 pts (63%) reached cycle 12 and 10/17 (59%) continued treatment: 2/10 (20%) experienced CI, whereas 8/10 (80%) fulfilled the CB criterion; 19/27 pts (70%) were still on treatment at the time of data cut-off. Among all 67 pts analyzed, 42% (28/67) were on treatment for more than 12 cycles and 24% (16/67) for more than 24 cycles; 3 pts (4%) were treated for more than 60 cycles due to sustained response or CB. Of note, mean Hb increased from 8.7 g/dL at baseline to 9.6 g/dL at end of cycle 18 and remained stable thereafter (Figure 1). Conclusions: Combination treatment using RUX plus POM is feasible in pts with poor-risk MF and resulted in an objective anemia response rate of 18% in co1. Of note, 42% of pts were treated with >12 cycles and showed a longer lasting stabilization of their disease with sustained improvement of Hb and QoL. Step-wise increase of the POM dose in co2 is safe and feasible with 70% of pts still on study treatment. Updated efficacy results of co2 with longer follow-up data will be presented at the meeting. Figure 1 Disclosures Stegelmann: Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Koschmieder:Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers-Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis Foundation: Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Ariad: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AOP Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; CTI: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Shire: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Isfort:Novartis: Consultancy, Honoraria, Other: Travel reimbursement; Pfizer: Consultancy, Honoraria, Other: Travel reimbursement; Ariad: Consultancy, Honoraria; BMS: Honoraria; Hexal: Other: Travel reimbursement; Amgen: Other: Travel reimbursement; Mundipharma: Other: Travel reimbursement; Roche: Other: Travel reimbursement; Alexion: Other: Travel reimbursement. Hochhaus:Pfizer: Research Funding; Novartis: Research Funding; BMS: Research Funding; Incyte: Research Funding; MSD: Research Funding. Göthert:Bristol-Myers Squibb: Consultancy, Honoraria, Other: Travel support; Incyte: Consultancy, Honoraria, Other: Travel support; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Travel support; Proteros Biostructures: Consultancy; AOP Orphan Pharmaceuticals: Honoraria, Other: Travel support. Schafhausen:Incyte: Consultancy, Equity Ownership, Honoraria; Novartis: Consultancy, Honoraria. Radsak:Daiichi Sankyo: Other: Travel Support, Advisory Boards; Novartis: Other: Travel Support, Advisory Boards; JAZZ: Other: Travel Support; Celgene: Other: Travel Support, Advisory Boards; Takeda: Other: Advisory Boards; Otsuka: Other: Advisory Boards. von Bubnoff:Novartis: Research Funding. Reiter:Blueprint: Consultancy, Honoraria, Other: Travel reimbursement; Novartis: Consultancy, Honoraria, Other: Travel reimbursement, Research Funding; Deciphera: Consultancy, Honoraria, Other: Travel reimbursement. Döhner:Celgene, Novartis, Sunesis: Honoraria, Research Funding; AbbVie, Agios, Amgen, Astellas, Astex, Celator, Janssen, Jazz, Seattle Genetics: Consultancy, Honoraria; AROG, Bristol Myers Squibb, Pfizer: Research Funding. Griesshammer:Novartis: Consultancy, Honoraria, Speakers Bureau. Döhner:Daiichi: Honoraria; Jazz: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Janssen: Honoraria; CTI Biopharma: Consultancy, Honoraria.

In this phase Ib/IIa study (ClinicalTrials.gov Identifier: NCT00850382) of the German-Austrian AML Study Group (AMLSG) the multikinase inhibitor dasatinib was added to intensive induction and consolidation chemotherapy and administered as single agent for 1-year maintenance in first-line treatment of adult patients with core-binding factor (CBF) acute myeloid leukemia (AML). The primary combined end point in this study was safety and feasibility, and included the rates of early (ED) and hypoplastic (HD) deaths, pleural/pericardial effusion 3°/4° and liver toxicity 3°/4°, and the rate of refractory disease. Secondary end points were cumulative incidence of relapse (CIR) and death in complete remission (CID), and overall survival (OS). Eighty-nine pts [median age 49.5 years, range: 19-73 years; t(8;21), n = 37; inv (16), n = 52] were included. No unexpected excess in toxicity was observed. The rates of ED/HD and CR/CRi were 4.5% (4/89) and 94% (84/89), respectively. The 4-year estimated CIR, CID, and OS were 33.1% [95%-CI (confidence interval), 22.7-43.4%], 6.0% (95% CI, 0.9-11.2%), and 74.7% (95% CI, 66.1-84.5%), respectively. On the basis of the acceptable toxicity profile and favorable outcome in the AMLSG 11-08 trial, a confirmatory randomized phase III trial with dasatinib in adults with CBF-AML is ongoing (ClinicalTrials.gov Identifier: NCT02013648).

SummaryThe antiphospholipid syndrome (APS) is an autoimmune disease characterised by thromboembolic events and/or pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). Here we show that three cofactor independent human monoclonal aPL can induce transcription of NLRP3 and caspase-1 resulting in inflammasome activation specific for NLRP3. This depends fully on activation of endosomal NADPH-oxidase-2 (NOX2) by aPL. Activation of NOX2 and subsequent inflammasome activation by aPL are independent from TLR2 or TLR4. While endosomal superoxide production induces caspase-1 and NLRP3 transcription, it does not affect prae-IL-1β transcription. Therefore, release of IL-1β occurs only after activation of additional pathways like TLR7/8 or TLR2. All effects exerted by the monoclonal aPL can be reproduced with IgG fractions of APS patients proving that the monoclonal aPL are representative for the APS. IgG fractions of healthy controls or patients suffering from systemic lupus erythematosus have no effect. In a mouse model of the APS we can show inflammasome activation in vivo. Furthermore, mononuclear cells isolated from patients with the APS show an increased expression of caspase-1 and NLRP3 which is accompanied by a three-fold increased serum concentration of IL-1β suggesting chronic inflammasome activation in APS patients. In summary, we provide further evidence that endosomal NOX2 can be activated by cofactor independent aPL. This leads to induction of the NLRP3 inflammasome. Our data indicate that cofactor independent aPL might contribute significantly to the pathogenesis of the APS.

Graft-versus-host disease (GVHD) is a frequent life-threatening complication after allogeneic hematopoietic stem cell transplantation (HSCT) and induced by donor-derived T cells that become activated by host antigen-presenting cells. To address the relevance of host dendritic cell (DC) populations in this disease, we used mouse strains deficient in CD11c(+) or CD8α(+) DC populations in a model of acute GVHD where bone marrow and T cells from BALB/c donors were transplanted into C57BL/6 hosts. Surprisingly, a strong increase in GVHD-related mortality was observed in the absence of CD11c(+) cells. Likewise, Batf3-deficient (Batf3(-/-)) mice that lack CD8α(+) DCs also displayed a strongly increased GVHD-related mortality. In the absence of CD8α(+) DCs, we detected an increased activation of the remaining DC populations after HSCT, leading to an enhanced priming of allogeneic T cells. Importantly, this was associated with reduced numbers of regulatory T cells and transforming growth factor-β levels, indicating an aggravated failure of peripheral tolerance mechanisms after HSCT in the absence of CD8α(+) DCs. In summary, our results indicate a critical role of CD8α(+) DCs as important inducers of regulatory T cell-mediated tolerance to control DC activation and T cell priming in the initiation phase of GVHD.

Infections and infectious complications are the major cause of morbidity and mortality in febrile neutropenic patients after autologous stem cell transplantation. Laboratory biomarkers are helpful for early identification of critically ill patients and optimal therapy management. Several studies in adult non-neutropenic patients proposed sTREM-1 as a superior biomarker for identification of septic patients as well as a predictor for survival in these patients compared with procalcitonin (PCT), C-reactive protein (CRP), or interleukin-8 (IL-8). Here, to assess the utility of PCT, CRP, IL-8, and sTREM-1 in febrile neutropenia, 44 patients presenting with febrile neutropenia after autologous stem cell transplantation were recruited in a single-center prospective pilot study. We analyzed PCT and CRP as well as IL-8 and sTREM-1 levels pre- and post-transplantation at defined time points. In 20 of 44 patients, concentration of sTREM-1 was under the detection level at appearance of febrile neutropenia. Mean levels of PCT, IL-8, and CRP were significantly increased in infections of critically ill patients who by dysfunction or failure of one or more organs/system depend on survival from advanced instruments of monitoring and therapy. However, all tested biomarkers could not distinguish between presence and absence of bloodstream infection. The combination of the biomarkers PCT and IL-8 achieved a high sensitivity of 90% and specificity of 74% for the identification of serious complications in febrile neutropenia, whereas the combination of CRP and PCT or IL-8 achieved a high sensitivity of 100%, but with the addition of a low specificity of 47or 41%. In conclusion, we found that the measurement of sTREM-1 concentration at presentation of febrile neutropenia is not useful to identify bacterial bloodstream infections and critically ill patients. PCT and IL-8 are useful biomarkers for the early identification of critically ill patients, compared to CRP and sTREM-1 in febrile neutropenia. PCT or IL-8 in combination with clinical parameters should be considered in routine measurement to identify critically ill patients as early as possible.

Background The epidermal application of the Toll Like Receptor 7 agonist imiquimod and a T-cell peptide epitope (transcutaneous immunization, TCI) mediates systemic peptide-specific cytotoxic T-cell (CTL) responses and leads to tumor protection in a prophylactic tumor setting. However, it does not accomplish memory formation or permanent defiance of tumors in a therapeutic set-up. As a distinct immunologic approach, CTLA-4 blockade augments systemic immune responses and has shown long-lasting effects in preclinical experiments as well as in clinical trials. Objective The study investigates the vaccination capacity of TCI in combination with the checkpoint inhibitor CTLA-4 in matters of primary response, memory formation and tumor protection and characterizes the role of regulatory T cells (Tregs). Methods After performing TCI with IMI-Sol (containing 5% Imiquimod) and the model epitope SIINFEKL, 6–8 week old C57BL/6 mice received anti-CTLA-4 antibody either s.c or i.p. The CTL responses and frequency of peptide specific CD8+ T-cells were then evaluated on day 8. To determine anti-tumor effects, a therapeutic tumor challenge with B16 OVA melanoma was performed. Results The combination of s.c. anti-CTLA-4 antibody and TCI leads to an enhanced systemic cytotoxic response, to memory formation and allows significantly improved survival in a tumor setting with B16 OVA melanoma. Towards the mechanism, we show that in this vaccination protocol the CTLA-4 antibody acts mainly Treg-independent. Conclusion We demonstrate that the combination of TCI with IMI-Sol and anti-CTLA-4 can confer potent immune responses and tumor-protection. These results might contribute to the development of advanced vaccination approaches targeting tumors or persistent infectious diseases.

Myelodysplastic Syndromes are oligo-clonal stem cell disorders that are associated with cytopenias in the peripheral blood. Major causes for morbidity and mortality in myelodysplastic syndromes (MDS) patients are infections mostly due to bacteria or fungi. Beside leucopenia per se in affected patients, function of white blood cells particularly that of neutrophils seems to be impaired. Here we summarize the available data on infections in MDS patients in general and particularly those treated with 5-azacitidine.

Background FLT3-ITD mutations occur in about 25% of patients (pts) with acute myeloid leukemia (AML) and are associated with poor outcomes. Pts with relapsed/refractory (R/R) FLT3-ITD AML have worse prognosis and high unmet medical need. Quizartinib (Q) is a potent and selective FLT3i with promising activity and a manageable safety profile. QuANTUM-R was a global, phase 3, randomized trial of Q vs chemotherapy (SC) in pts with R/R FLT3-ITD AML (NCT02039726). Methods Pts with R/R FLT3-ITD AML w/wo hematopoietic stem cell transplant (HSCT) were randomized to receive Q or a preselected investigator choice SC: low-dose cytarabine; mitoxantrone, etoposide, and intermediate-dose cytarabine (MEC); or fludarabine, cytarabine, and G-CSF with idarubicin (FLAG-IDA). Prior midostaurin was allowed. Pts receiving HSCT after Q could resume Q after HSCT. Primary and secondary endpoints were overall survival (OS) and event-free survival (EFS), respectively. Exploratory endpoints included response rate, time to and duration of response, and transplant rate. Results 367 pts were randomized; 245 to Q and 122 to SC. Median follow-up was 23.5 mo. OS hazard ratio (HR) of Q relative to SC was 0.76 (95% CI, 0.58-0.98; P=.0177). Median OS was 6.2 (95% CI, 5.3-7.2) vs 4.7 (95% CI, 4.0-5.5) mo in Q and SC arms, respectively. EFS HR was 0.90 (95% CI, 0.70-1.16; P=.1071); median EFS was 1.4 (95% CI, 0.0-1.9) vs 0.9 (95% CI, 0.4-1.3) mo, respectively. Sensitivity analyses and OS subgroup analyses supported Q vs SC. Composite complete response (CRc) was 48% and 27% in Q and SC arms, respectively. Transplant rate was 32% (Q) and 12% (SC). Median time to first CRc was 4.9 wk for Q. The most common grade ≥ 3 TEAEs in both arms were infections and those associated with cytopenia. Conclusion OS benefit was observed with single-agent Q vs SC in pts with R/R FLT3-ITD AML with a favorable Q safety profile, providing evidence of meaningful clinical benefit in pts with limited treatment options.

Introduction: FLT3-ITD mutations are among the most common molecular abnormalities in AML, occurring in ≈ 25% of pts. These driver mutations are associated with high leukemic burden and poor prognosis, eg, high risk of relapse, decreased response to salvage therapy, and shorter overall survival (OS). Pts with R/R FLT3-ITD AML have a worse prognosis and represent a population with high unmet medical need. Q is a once-daily, oral, highly potent and selective FLT3i shown in phase 2 trials to have promising single-agent antileukemic activity and a manageable safety profile. QuANTUM-R was the first global, phase 3, randomized controlled trial (NCT02039726) to show that an FLT3i prolonged OS compared with salvage chemotherapy (SC) in pts with R/R FLT3-ITD AML. Final efficacy and safety data from this pivotal phase 3 trial are reported. Methods: Pts aged ≥ 18 years with FLT3-ITD AML refractory to or relapsed (duration of first remission ≤ 6 mo) after standard AML therapy, w/wo hematopoietic stem cell transplant (HSCT) were randomized 2:1 to receive Q (60 mg [30-mg lead-in]) or 1 of 3 preselected investigator's choice (IC) SC: low-dose cytarabine (LoDAC); mitoxantrone, etoposide, and intermediate-dose cytarabine (MEC); or fludarabine, cytarabine, and granulocyte-colony stimulating factor (G-CSF) with idarubicin (FLAG-IDA). Up to 2 cycles of MEC or FLAG-IDA were permitted; Q and LoDAC were given until lack of benefit, unacceptable toxicity, or HSCT. Prior therapy with midostaurin was allowed, but all other FLT3i were not. Pts receiving HSCT in the Q arm could resume Q after HSCT. Primary and secondary endpoints were OS and event-free survival (EFS), respectively. Sensitivity analyses for OS and EFS were conducted: (1) using the per-protocol set (randomized and treated patients without major protocol deviations), (2) censoring at HSCT, (3) censoring at the use of other postbaseline FLT3i (for OS only). Predefined subgroup analyses of OS were also performed. Exploratory endpoints included response rates, duration of CRc, and transplant rate. Results: 367 pts were randomized; 245 to Q and 122 to IC SC (LoDAC, n=29; MEC, n=40; FLAG-IDA, n=53). Four pts randomized to Q and 28 pts randomized to SC did not receive therapy. Median follow-up was 23.5 mo. Six pts were still on initial Q treatment at data cutoff vs 0 in the SC arm. Treatment groups were well balanced for baseline characteristics, including age, response to prior therapy, transplant history, and FLT3-ITD allelic burden. OS hazard ratio (HR) of Q relative to SC was 0.76 (95% CI, 0.58-0.98; stratified log-rank test, 1-sided P=0.0177). Median OS was 6.2 (95% CI, 5.3-7.2) vs 4.7 (95% CI, 4.0-5.5) mo, with an estimated 12-mo OS probability of 27% vs 20% in Q and SC arms, respectively. EFS HR was 0.90 (95% CI, 0.70-1.16; stratified log-rank test, 1-sided P=0.1071); median EFS was 6.0 (95% CI, 0.1-8.3) vs 3.7 (95% CI, 0.4-5.9) wk, respectively. Sensitivity analyses of OS and EFS all supported benefit of quizartinib compared with SC, as did OS analyses across subgroups, including varying allelic ratio, prior HSCT, AML risk score, and response to prior therapy (Tables 1 and 2, Figure). CRc was 48% (95% CI, 42%-55%) and 27% (95% CI, 19%-36%) in Q and SC arms (nominal P=0.0001), respectively. Duration of CRc was 12.1 (95% CI, 10.4-27.1) vs 5.0 (95% CI, 3.3-12.6) wk. Transplant rate was 32% and 12% in Q and SC arms (nominal P Rates of treatment-emergent adverse events (TEAEs) were comparable between the 2 arms, despite higher total drug exposure in Q vs SC arms (101.9 vs 3.7 patient-years [pt-y], respectively). Exposure-adjusted TEAEs were 2.3 vs 25.2 per pt-y, respectively. Most common grade ≥ 3 TEAEs in both arms were infections and those associated with cytopenia. Only 2 pts discontinued Q due to QTcF prolongation. QTcF >500 ms (grade 3) by central laboratory was 3% in the Q arm; no grade 4 QTcF occurred. Q-treated pts post-HSCT had a similar AE profile to those overall. Conclusions: This report confirms the survival benefit observed with single-agent Q compared with SC in pts with R/R FLT3-ITD AML and the favorable Q safety profile, providing evidence of meaningful clinical benefit in pts who have few options. These results are paradigm changing in the R/R FLT3-ITD AML treatment setting. Disclosures Cortes: Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Astellas Pharma: Consultancy, Research Funding; Arog: Research Funding. Khaled:Juno: Other: Travel Funding; Daiichi: Consultancy; Alexion: Consultancy, Speakers Bureau. Perl:Arog: Consultancy; Pfizer: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy; NewLink Genetics: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy; AbbVie: Membership on an entity's Board of Directors or advisory committees; Actinium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Ganguly:Amgen: Consultancy; Janssen: Consultancy; Daiichi Sankyo: Research Funding; Seattle Genetics: Speakers Bureau. Russell:Daiichi Sankyo: Consultancy; Jazz Pharma: Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau. Kramer:Daiichi Sankyo: Consultancy; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding. Dombret:Daiichi Sankyo: Honoraria; Roche/Genentech: Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Pfizer: Honoraria; Ariad: Honoraria, Research Funding; Novartis: Honoraria; Celgene: Consultancy, Honoraria; Jazz Pharma: Honoraria, Research Funding; Agios: Honoraria; Sunesis: Honoraria; Karyopharm: Honoraria; Kite Pharma: Honoraria, Research Funding; Menarini: Honoraria; Astellas: Honoraria; Janssen: Honoraria; Servier: Honoraria; Seattle Genetics: Honoraria. Jonas:Accelerated Medical Diagnostics: Research Funding; Incyte: Research Funding; Esanex: Research Funding; LP Therapeutics: Research Funding; AbbVie: Consultancy, Research Funding; Daiichi Sankyo: Research Funding; Kalobios: Research Funding; Pharmacyclics: Research Funding; Celgene: Consultancy, Research Funding; Genentech/Roche: Research Funding; Glycomimetics: Research Funding; Tolero: Consultancy; Amgen: Consultancy; Forma: Research Funding. Leung:Novartis: Speakers Bureau; Daiichi: Research Funding. Mehta:Daiichi Sankyo: Honoraria. Montesinos:Daiichi Sankyo: Consultancy, Speakers Bureau; Novartis: Research Funding, Speakers Bureau. Radsak:Novartis: Consultancy, Honoraria; Jazz Pharmaceuticals: Other: Travel grant; TEVA: Consultancy; Daiichi Sankyo: Honoraria, Other: Travel grant; Gilead: Other: Travel grant; Celgene: Honoraria, Other: Travel grant; Takeda: Consultancy. Arunachalam:Daiichi Sankyo: Employment. Holmes:Daiichi Sankyo: Employment. Kobayashi:Daiichi Sankyo: Employment. Namuyinga:Daiichi Sankyo: Employment. Ge:Daiichi Sankyo: Employment. Yver:Daiichi Sankyo: Employment. Zhang:Daiichi Sankyo: Employment.

Background The Nod-like receptor NACHT, LRR, and PYD domain–containing protein 3 (NLRP3) and Bruton tyrosine kinase (BTK) are protagonists in innate and adaptive immunity, respectively. NLRP3 senses exogenous and endogenous insults, leading to inflammasome activation, which occurs spontaneously in patients with Muckle-Wells syndrome; BTK mutations cause the genetic immunodeficiency X-linked agammaglobulinemia (XLA). However, to date, few proteins that regulate NLRP3 inflammasome activity in human primary immune cells have been identified, and clinically promising pharmacologic targeting strategies remain elusive. Objective We sought to identify novel regulators of the NLRP3 inflammasome in human cells with a view to exploring interference with inflammasome activity at the level of such regulators. Methods After proteome-wide phosphoproteomics, the identified novel regulator BTK was studied in human and murine cells by using pharmacologic and genetic BTK ablation. Results Here we show that BTK is a critical regulator of NLRP3 inflammasome activation: pharmacologic (using the US Food and Drug Administration–approved inhibitor ibrutinib) and genetic (in patients with XLA and Btk knockout mice) BTK ablation in primary immune cells led to reduced IL-1β processing and secretion in response to nigericin and the Staphylococcus aureus toxin leukocidin AB (LukAB). BTK affected apoptosis-associated speck-like protein containing a CARD (ASC) speck formation and caspase-1 cleavage and interacted with NLRP3 and ASC. S aureus infection control in vivo and IL-1β release from cells of patients with Muckle-Wells syndrome were impaired by ibrutinib. Notably, IL-1β processing and release from immune cells isolated from patients with cancer receiving ibrutinib therapy were reduced. Conclusion Our data suggest that XLA might result in part from genetic inflammasome deficiency and that NLRP3 inflammasome–linked inflammation could potentially be targeted pharmacologically through BTK.