ALBERT

Description: The incidence of obesity continues to rise with over 50% of the world's population predicted to be overweight/obese by the year 2030. The global health impact of this trend is concerning given that obesity is a risk factor for developing cancers of varying etiologies. Alarmingly, the survival outcomes for obese patients with cancer are lower than those observed in lean patients. Obesity is characterized by the accumulation of adipocytes which alters drug dynamics and impacts the function of cancer and immune cells in the tumor microenvironment. Obesity-induced immune defects are troubling given the increasing use of immunotherapy in the treatment of malignancies. Here we show that adipocyte-secreted factors upregulate immunosuppressive mechanisms on human B-cell acute lymphoblastic leukemia (B-ALL) cells, attenuate the function of endogenous T-cells, and compromise the efficacy of T-cell based immunotherapies. To study the impact of adiposity on T-cell function, CD4+ and CD8+ T-cells were purified from the spleens of C57BL/6 mice and activated with PMA/Ionomycin for 72 hours in unconditioned media (UCM), bone marrow stromal-cell conditioned media (SCM), and adipocyte-conditioned media (ACM) followed by flow cytometry analysis for surface marker expression, cytokine production, and the induction of cytolytic mediators. Interestingly, T-cells activated in ACM, but not UCM or SCM, showed an attenuated phenotype highlighted by decreased CD44 and PD-1 expression, diminished cytokine production (IFN-γ/TNF-α) and reduced induction of cytolytic mediators (granzyme B/perforin). These observations were also true in obese, relative to lean, patients with B-ALL where we found that T-cells purified from the peripheral blood mononuclear cells (PBMCs) failed to produce significant levels of TNF-α when stimulated with PMA/Ionomycin. In all, these results demonstrate that adipocyte-secreted factors directly compromise the function of endogenous T-cells, which phenocopies T-cell defects observed in obese relative to lean pediatric patients with B-ALL. We next assessed the impact of adiposity on malignant cells by culturing human B-ALL cell lines in the conditioned mediums described above and performed flow cytometric analysis to assess their surface expression of the B-cell lineage antigen CD19 and proteins that modulate immunity. In addition to being a marker for B-cells, CD19 is the primary target of the T-cell based immunotherapies Blinatumomab and CAR T-cells directed against B-ALL cells. Surprisingly, when human B-ALL cells were co-cultured with adipocytes, every cell line tested (n=6) exhibited lower surface CD19 expression with 5 out 6 reaching statistical significance. Furthermore, adipocyte-secreted factors alone were sufficient to reduce CD19 surface levels on B-ALL cells in 2 of the 6 cell lines tested. Human B-ALL cells cultured in ACM, but not UCM or ACM, also upregulated their surface expression of the immunoinhibitory proteins HVEM, PD-L1, and PD-L2. These results demonstrate that adipocytes directly induce the downregulation of CD19 on human B-ALLs and increase their immune evasive capacity. Given these observations, we hypothesized that adipocyte-secreted factors would compromise T-cell-based immunotherapies targeting CD19-expressing B-ALL cells. To this end, primary human T-cells were engineered to express a CD19-directed chimeric antigen receptor (CAR). CAR T-cells and human B-ALL cells were separately pre-treated for 24 hours in UCM, SCM or ACM followed by co-culture for cytolytic analysis using Annexin-V/PI staining. Adipocyte-secreted factors significantly inhibited CAR T-cell mediated killing of CD19-expressing B-ALL cells at 4 hours. In addition to CAR T-cells, we tested the leukemia killing efficacy of the bispecific T-cell engager, Blinatumomab. After 3 days of culture, we found that Blinatumomab significantly increased the killing capacity of endogenous T-cells with 60-80% of B-ALL cells being killed after 3 days of culture in UCM and SCM. In contrast, we found that ACM significantly compromised the efficacy Blinatumomab with only 30% of B-ALL cells being killed over 3 days when co-cultured with human T-cells. Our pre-clinical data highlights the negative impact of an adipose-rich microenvironment on T-cell function and B-ALL immunogenicity, which subsequently compromises the efficacy of multiple classes of immunotherapies targeting CD19. Disclosures No relevant conflicts of interest to declare.

Description: Background:Advances in medical care have resulted in nearly 95% of all children with sickle cell disease (SCD) living to adulthood. Standardized transition programming does not currently exist, resulting in high rates of mortality and morbidity among young adults (YA) during the transition period. Mentoring and social support have been used to impact health behavior change. Medical student mentors can serve as mentors offering specialized support for YA. This study examined the feasibility and preliminary efficacy of a medical student mentor intervention to improve transition outcomes for YAs with SCD. Methods:24 YA with sickle cell disease and 9 medical student mentors enrolled in the intervention. Feasibility and acceptability of the intervention was assessed through enrollment rates, reasons for refusal, retention rates, engagement with the intervention, satisfaction, and reasons for drop-out. The preliminary efficacy of the intervention among patient participants was assessed using dependent t-tests to evaluate changes in transition readiness, health related quality of life, self-efficacy, SCD knowledge medication adherence, and health literacy. Among medical student mentor participants, changes in attitudes towards chronic illness and SCD knowledge were explored. Results:Patient participants demonstrated adequate enrollment (63.2%), retention (75.0%), and adherence to the intervention (88.3%) and rated the intervention components highly. Patient participants demonstrated significant improvements in transition readiness (p= .001), self-efficacy (p= .002), medication adherence (p= .02), and health literacy (p= .05). Medical students also demonstrated significant improvements in SCD knowledge (p= .01). Discussion:A medical student mentor intervention to facilitate transition from pediatric to adult care for young adults with SCD is both feasible and acceptable to patients and medical students. Preliminary evidence suggests such an intervention may provide dual benefit for both patients and students. A randomized controlled trial is needed to evaluate efficacy. Disclosures No relevant conflicts of interest to declare.

Description: INTRODUCTION Anti-CD19 CAR T-cell immunotherapy is promising for patients with relapsed/refractory CLL. Hypogammaglobinemia can result from normal CD19+ B-cell depletion by CAR-T cells. CLL patients are already at risk for infections due to impaired immune function, lymphodepletion prior to CAR-T cells infusion, and immunosuppressive therapies. Intravenous immunoglobulin (IVIG) is used to manage hypogammaglobulinemia, although standard criteria for IVIG administration in this setting has not been established. We studied the incidence of hypogammaglobinemia and report infectious complications, risk factors, IVIG use, and clinical outcomes for CLL patients treated with anti-CD19 CAR-T cells. METHODS Adult CLL patients who received CD19-directed CAR-T therapy in 3 clinical trials (NCT01029366, NCT01747486, NCT02640209) from July 2010 to February 2020 were included. We reviewed demographics, available IgG levels, IVIG use, and clinical outcomes with a particular focus on infectious complications. Hypogammaglobulinemia was defined as IgG

Description: Despite advances that have greatly improved the overall survival of pediatric B cell acute lymphoblastic leukemia (B-ALL), it remains one of the leading causes of cancer-related death in children. Immunotherapy has shown efficacy in treatment of refractory disease, highlighting the need for greater understanding of the immune evasion mechanisms underlying this disease so that additional immune modulating therapeutic strategies can be developed. Siglec-15 (Sig15) was recently reported to have immune modulatory functions in the context of solid tumors. We have found that SIGLEC15 is overexpressed at the RNA level in primary B cell acute lymphoblastic leukemia (B-ALL), acute myelogenous leukemia (AML), and diffuse large B cell lymphoma as compared to healthy donor controls. As compared to healthy donor PBMCs, we have confirmed higher expression of Sig15 at the RNA and protein levels through RT-qPCR, immunoblotting, and flow cytometry across a panel of human B-ALL, AML, DLBCL, and T cell acute lymphoblastic leukemia (T-ALL) cell lines. Knockout of Sig15 expression in a BCR-ABL1+ murine model of B-ALL engrafted in immunocompetent and Rag1-/- immunodeficient recipients resulted in leukemia clearance in immunocompetent, but not immunodeficient, recipients and 100% survival (Figure 1). These data suggest a prominent role for Sig15 in the suppression of adaptive immune response to B-ALL as well as other hematological malignancies. Additional studies suggest that SIGLEC15 expression is positively regulated by NFκB signaling, which is known to be constitutively activated in certain B-ALL subsets. Importantly, we have observed release of a soluble form of Sig15 (sSig15) from B-ALL cells, which is regulated by PKC and calcineurin-mediated signaling. To discover translational application, we measured sSig15 in the plasma of both healthy and pediatric leukemia patients and found significantly higher levels of sSig15 as compared to healthy individuals (Figure 2; LLD = 5 pg/ml; **P

Description: Introduction: High-grade B cell lymphoma (HGBCL) with rearrangements of MYC in addition to either BCL2 or BCL6 (DHL) generally has a poor prognosis for response to conventional therapies. Nevertheless, current studies of responses to anti-CD19 CAR-T cell therapies (CAR-T) have not demonstrated poorer overall response rates (ORR) in patients with DHL (Locke Lancet Oncol 2019, Schuster NEJM 2019). Double expressor diffuse large B-cell lymphoma (DEL), which lacks the chromosomal rearrangements of DHL but overexpresses MYC and BCL2 proteins by immunohistochemistry, has been similarly associated with poor outcomes, including after autologous and allogeneic stem cell transplantation (Herrera JCO 2017; Kawashima Biol Blood Marrow Transplant, 2018). DEL and DHL each have a different cell of origin and biology; DEL is typically activated B cell-like phenotype, whereas DHL typically have germinal center-like phenotype. To our knowledge, the association of DEL and outcomes with CAR-T has not been assessed. We aimed to assess whether DEL is associated with outcome after CAR-T. Methods: We retrospectively reviewed the records of 75 consecutive patients with aggressive B-cell lymphomas treated with commercial CAR-T therapy at the University of Pennsylvania between April 2018 and October 2019. We included all patients with either diffuse large B cell lymphoma or HGBCL who had both: a) fluorescence in situ hybridization testing for MYC, BCL2 and BCL6 chromosomal rearrangements, and b) immunohistochemical staining (IHC) for MYC and BCL2. Patients who had both MYC and BCL2 and/or BCL6 chromosomal rearrangements were classified as DHL; patients with IHC expression of both MYC in 〉 40% and BCL2 in 〉 50% of tumor cells without meeting criteria for DHL were classified as DEL. Patient characteristics were collected. Fisher's exact test was used to compare overall response rate (ORR) and log-rank test was used for comparison of progression-free survival (PFS). Results: Seventy-five eligible cases of aggressive B-cell lymphoma were identified; 9 were excluded due to non-DLBCL or HGBCL subtype and 16 were excluded due to insufficient characterization of tissue to assess DHL and DEL status. Fifty patients were eligible for analysis; 18 patients (36%) met criteria for DEL, 10 patients (20%) met criteria for DHL, and the remaining 44% of patients had neither DEL nor DHL (non-DEL/DHL). Tisagenlecleucel was administered to 39 patients, whereas axicabtagene ciloleucel was administered to 11 patients. Median age at leukapheresis was 65 years (range: 35-81). LDH, administration of bridging therapy, and ECOG performance status (PS) did not significantly differ between the three groups. Median follow-up for the entire cohort was 15.9 months. For all patients, best ORR was 54% (27/50 patients), median PFS was 3.7 months (95%CI: 2.8-NE), and median OS was not reached. Best ORR was 56% (10/18) for DEL patients, 50% (5/10) for DHL patients, and 55% (12/22) for patients with non-DEL/DHL. ORR did not differ between these groups (p=1.0). There was no difference in PFS (see Figure, p=0.90), OS (p=0.61), or RD (p=0.38) between the three groups. At 16 months, 69% of responding DEL continue in CR (95%CI: 30-89%), 72% of non-DEL/DHL (95%CI: 35-90%) continue in CR, and 100% of DHL (95%CI: NE) continue in CR. Conclusions: The proportion of patients with DEL in our study was similar to that reported for patients with diffuse large B-cell lymphoma in the literature. There were no significant differences between DEL, DHL, and non-DEL/DHL groups with regard to the proportion of patients with elevated LDH, bridging therapy, or ECOG PS. Although DHL and DEL have a negative prognostic impact on response to salvage therapies and hematopoietic stem cell transplant, neither DHL nor DEL status was associated with inferior response to anti-CD19 commercial CAR-T products. We demonstrate that patients with DEL can achieve prolonged responses after CAR-T. Moreover, neither DEL nor DHL status appeared to impact PFS, OS, or RD outcomes after commercial CAR-T. Figure Disclosures Chong: BMS: Membership on an entity's Board of Directors or advisory committees; Tessa: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; KITE Pharma: Membership on an entity's Board of Directors or advisory committees. Landsburg:Curis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Triphase: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Speakers Bureau; Takeda: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Gerson:Loxo: Research Funding; Genentech: Consultancy; Pharmacyclics: Consultancy; Abbvie: Consultancy. Svoboda:Atara: Consultancy; Genmab: Consultancy; TG: Research Funding; Adaptive: Consultancy; Astra-Zeneca: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Imbrium: Consultancy; Seattle Genetics: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Merck: Research Funding; Incyte: Research Funding. Dwivedy Nasta:Merck: Membership on an entity's Board of Directors or advisory committees; Roche: Research Funding; Debiopharm: Research Funding; Forty Seven: Research Funding; Incyte: Research Funding; Atara: Research Funding; Rafael Pharmaceuticals: Research Funding. Barta:Atara: Honoraria; Pfizer: Honoraria; Janssen: Honoraria; Seattle Genetics: Honoraria, Research Funding; Monsanto: Consultancy. Garfall:Novartis: Research Funding; Tmunity: Consultancy, Other: Personal fees, Research Funding; Amgen: Research Funding; Kite Pharma: Other: Personal fees; Janssen: Consultancy, Research Funding; GSK: Consultancy; Surface Oncology: Consultancy. Ruella:UPenn/Novartis: Patents & Royalties; Abclon, BMS, NanoString: Consultancy; Abclon: Consultancy, Research Funding. Frey:Amgen: Consultancy, Honoraria; Kite Pharma: Consultancy, Honoraria; Syntax: Consultancy, Honoraria. Porter:Incyte: Other: Advisory board; Novartis: Honoraria, Other: Advisory board, Patents & Royalties: CAR T cells for CD19+ malignancies, Research Funding; Janssen: Other: Advisory board; Genentech/Roche: Current equity holder in publicly-traded company, Other: Spouse employment (ended Sept 2020); her salary includes stock/options; Glenmark: Other: Advisory board; National Marrow Donor Program: Membership on an entity's Board of Directors or advisory committees; American Board of Internal Medicine: Other: Member, exam writing committee (end date Oct 2019); Tmunity: Patents & Royalties; Adicet bio: Other: Advisory board; Kite/Gilead: Other: Advisory board. Schuster:AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria; Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding.

Description: Introduction Betibeglogene autotemcel (beti-cel; LentiGlobin for β-thalassemia) gene therapy is being evaluated for the treatment of transfusion-dependent β-thalassemia (TDT). Initial positive results of beti-cel in the phase 3 studies, HGB-207 (NCT02906202; non-β0/β0 genotypes) and HGB-212 (NCT03207009; β0/β0, β0/β+ IVS-I-110 and β+ IVS-I-110/β+ IVS-I-110 genotypes), showed 10/12 adult patients achieved transfusion independence. The studies expanded enrollment to include adolescents and children. We present interim results from pediatric patients

Description: Introduction Individuals with sickle cell disease (SCD) experience recurrent acute vaso-occlusive events (VOE) beginning in infancy, that can be prevented with hydroxyurea therapy (Wang W. Lancet 2011), while chronic organ dysfunction becomes evident in adolescence and progresses with age. Nutritional insufficiencies and deficiencies occur in SCD (e.g., zinc, vitamin D and B6), and are associated with greater frequency of VOE (McCaskill M. Nutrients 2018, Martyres D. PBC 2016, Schall J. J Pediatr 2004). While infants and young children (age 1.0 miles from a supermarket was 37% and 16%, respectively. Living in a household without a vehicle and located 〉0.5 miles from a supermarket was associated with increased hospitalizations and ACU (Figure 1). The odds ratio (OR) of experiencing 〉0 hospitalizations or ACU were 1.3 (95%CI: 1.0-1.8) or 1.5 (95%CI: 1.1-2.0), for those living in a household without a vehicle and 〉0.5 miles from a supermarket, respectively. Living in a household with children and 〉1.0 mile from a supermarket was associated with high risk of experiencing 〉0 hospitalizations (OR: 1.5; 95%CI: 1.2-1.8) and 〉0 ACU (OR: 1.3; 95%CI: 1.1-1.7) (Figure 2). The accuracy of predicting a SCD-related acute event by age 6 years significantly improved when adding markers of poor food access to the predictive model (AUC increase: ≥0.06, p=0.01) (Figure 3). Conclusion Living in food deserts limits access to affordable and nutritious foods. Food deserts are associated with poor health outcomes among pre-school children with SCD. The prediction of acute care utilization in young childhood increases when food access is considered. Treatment with hydroxyurea did not mitigate the effects of reduced food access on the frequency of acute care utilization of young children with SCD. Disclosures Estepp: ASH, NHLBI: Research Funding; Daiichi Sankyo, Esperion, Global Blood Therapeutics: Consultancy; Global Blood Therapeutics, Forma Therapeutics, Pfizer, Eli Lilly and Co: Research Funding. Hankins:LINKS Incorporate Foundation: Research Funding; National Heart, Lung, and Blood Institute: Honoraria, Research Funding; Novartis: Research Funding; UptoDate: Consultancy; MJH Life Sciences: Consultancy, Patents & Royalties; Global Blood Therapeutics: Consultancy, Research Funding; American Society of Pediatric Hematology/Oncology: Honoraria.

Description: Introduction: Patients (pts) with transfusion-dependent (TD) β-thalassemia may require long-term red blood cell transfusions (RBCT) that can lead to iron overload and associated complications, which impact negatively on health-related quality of life (HRQoL). Administration of RBCT provides transient relief from anemia-related symptoms associated with β-thalassemia; reduction of RBCT may increase anemia-related symptoms and thereby worsen HRQoL. The phase 3 BELIEVE study (NCT02604433) showed that the first-in-class erythroid maturation agent luspatercept provided clinically meaningful reduction in RBCT burden, but the impact of luspatercept on HRQoL is not well understood. This analysis assessed the effect of luspatercept plus best supportive care (BSC, including RBCT, iron chelation therapy) vs placebo (PBO) plus BSC on HRQoL in pts with TD β-thalassemia. Methods: Pts received luspatercept (starting dose 1.0 mg/kg with titration up to 1.25 mg/kg every 3 weeks) or PBO, subcutaneously for ≥ 48 weeks plus BSC. HRQoL was assessed using the generic 36-item Short Form Health Survey (SF-36) and the thalassemia-specific Transfusion-dependent Quality of Life questionnaire (TranQol), at screening (≤ 4 weeks prior to first study dose) and every 12 weeks up to 48 weeks of treatment. The HRQoL evaluable population included all pts who completed the HRQoL assessment at screening and ≥ 1 post-screening assessment visit. The TranQol and SF-36 were considered complete if ≥ 75% and ≥ 50% of items, respectively, were answered at a given time point. The primary analysis assessed changes from baseline between groups up to Week 48. The primary domains of interest were: TranQol total score and Physical Health (PH); and the SF-36 Physical Component Summary (PCS), Physical Functioning (PF), and General Health (GH). Other domains were considered exploratory domains. Changes from baseline were compared using ANCOVA models adjusting for baseline domain scores and geographic region. In exploratory analyses, the proportion of pts achieving a clinically meaningful improvement in domain scores were compared between pts on luspatercept achieving a clinical response (≥ 50% reduction in RBCT burden over 12 weeks; ≥ 33% reduction in RBCT burden over 12 weeks; transfusion independence [TI] any 8 weeks; or TI any 12 weeks), and PBO. Results: 336 pts were randomized to treatment; 224 to luspatercept and 112 to PBO. The HRQoL evaluable population was 212 (94.6%) in the luspatercept arm and 104 (92.9%) in the PBO arm. HRQoL questionnaire compliance rates among pts still on treatment were 〉 87.5% for both questionnaires at Week 48. Baseline HRQoL scores were similar to the US general population for most SF-36 domains, although GH, Role-Emotional, and Role-Physical domain scores were impaired in the BELIEVE population. Mean scores on all primary and exploratory domains were stable over time in both treatment groups and did not differ between treatment groups at Week 24 and 48. When considering responders to luspatercept, pts receiving luspatercept and achieving a ≥ 50% reduction in RBCT burden over 12 weeks were significantly more likely than pts receiving PBO to have a clinically meaningful improvement in PCS (31.1% vs 16.5%; P = 0.024), and PF (30.0% vs 13.2%; P = 0.007) at Week 48 (Table). Statistically significant differences between luspatercept and PBO were also seen among pts achieving TI for any 8 or any 12 weeks for some SF-36 domains, but no statistical difference was seen in pts achieving a ≥ 33% reduction in RBCT burden for either SF-36 or TranQol domains although the proportion of pts with improved scores was higher with luspatercept, especially at Week 48. Conclusions: Overall, the addition of luspatercept to BSC reduced transfusion burden while sustaining TranQol and SF-36 HRQoL scores over time through Week 48 compared with those receiving PBO. Pts with TD β-thalassemia responding to luspatercept were more likely to achieve clinically meaningful improvements in HRQoL compared with PBO. Disclosures Cappellini: Genzyme/Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; CRISPR Therapeutics, Novartis, Vifor Pharma: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria. Taher:Silence Therapeutics: Consultancy; Vifor Pharma: Consultancy, Research Funding; Ionis Pharmaceuticals: Consultancy; BMS: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding. Piga:BMS: Research Funding; Novartis: Research Funding. Shah:Novartis, BMS: Consultancy, Honoraria, Speakers Bureau; Bluebird Bio: Consultancy, Honoraria; IQVIA: Consultancy, Membership on an entity's Board of Directors or advisory committees. Voskaridou:ADDMEDICA Company: Consultancy, Research Funding; BMS: Consultancy, Research Funding; ACCELERON Company: Consultancy, Research Funding; PROTAGONIST Company: Research Funding; GENESIS Company: Consultancy, Research Funding; NOVARTIS Company: Research Funding. Viprakasit:Agios Pharmaceuticals, Ionis Pharmaceuticals, La Jolla Pharmaceuticals, Protagonist Therapeutics, Vifor Pharma: Consultancy, Research Funding; BMS, Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Porter:Silence Therapeutics: Honoraria; La Jolla Pharmaceuticals: Honoraria; Vifor Pharmaceuticals: Honoraria; Protagonist Therapeutics: Honoraria; BMS: Consultancy, Honoraria; Agios Pharmaceuticals: Consultancy, Honoraria; bluebird bio, Inc.: Consultancy, Honoraria. Hermine:AB Science: Consultancy, Current equity holder in publicly-traded company, Honoraria, Patents & Royalties, Research Funding; BMS, Alexion, Novartis, Inatherys: Research Funding. Neufeld:Takeda: Consultancy; Octapharma: Consultancy; Novo Nordsik: Consultancy; genetech: Consultancy; Bayer: Other: DSMB; Imara Pharma: Other: DSMB service; ApoPharma/Chiezi: Other: DSMB service; Pfizer: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Acceleron Pharma: Consultancy, Other: DSMB. Thompson:BMS: Consultancy, Research Funding; Baxalta: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; CRISPR/Vertex: Research Funding; bluebird bio, Inc.: Consultancy, Research Funding; Biomarin: Research Funding. Tang:BMS: Current Employment, Current equity holder in publicly-traded company. Yu:Evidera: Current Employment. Guo:BMS: Consultancy. Shetty:BMS: Current Employment, Current equity holder in publicly-traded company. Miteva:BMS: Current Employment. Zinger:Celgene, a Bristol Myers Squibb company: Current Employment. Backstrom:Acceleron Pharma: Current Employment, Current equity holder in publicly-traded company; BMS: Current equity holder in publicly-traded company. Oliva:Abbvie: Consultancy; Amgen: Consultancy; Novartis: Consultancy; BMS: Consultancy, Honoraria, Patents & Royalties, Speakers Bureau; Alexion: Consultancy; Apellis: Consultancy.

Description: Introduction: While advances in front-line conventional chemotherapy have increased the likelihood of attaining remission in pediatric AML, relapse rates remain high (25-35%), and novel therapies are needed (Zhang, Savage et al. 2019). The clinical and molecular heterogeneity of AML makes it complex to study and creates challenges for the development of novel therapies (Bolouri, Farrar et al. 2018). It is important to identify cells and pathways underlying relapse to facilitate development of novel therapies. Single-cell RNA Sequencing (scRNA-Seq) allows in-depth analysis of the heterogeneous AML landscape to provide a detailed view of the tumor microenvironment, revealing populations of blasts and immune cells which may be relevant to relapse or complete remission. Methods: We analyzed ~36,500 cells from 14 pediatric AML bone marrow samples in our institutional biorepository, spanning different AML subtypes and 3 healthy children to generate a comprehensive scRNA-Seq landscape of immature AML-associated blasts and microenvironment cells. Samples collected at the time of diagnosis (Dx), end of induction (EOI), and relapse (Rel) were used to generate scRNA-Seq data using a droplet-based barcoding technique (Panigrahy, Gartung et al. 2019). After normalization of scRNA-Seq data, the cell clusters were identified using principal component analysis and Uniform Manifold Approximation and Projection (UMAP) approach (Becht et al, 2018). Differential expression, pathways and systems biology analysis between relapsed and remission patients reveal differences for specific cell clusters (Panigrahy, Gartung et al. 2019). To determine the clinical outcome association of our AML blast specific markers, survival analysis was performed on AML TARGET data (https://ocg.cancer.gov/programs/target) using cox proportional hazard survival approach. To characterize AML blast cells with high accuracy, we used support vector machine (SVM), an Artificial Intelligence based feature extraction and model development approach (Bhasin, Ndebele et al. 2016). Results:ScRNA-Seq analysis of paired Dx and EOI samples using UMAP identified three blast cell clusters with significant gene expression differences among different patients, indicating heterogeneity of AML blast cells (Fig 1a, b). Comparative analysis of the three Dx enriched blast cell clusters with other cells identified a "core blast cell signature" with overexpression of genes like AZU1, CLEC11A, FLT3, and NREP (Fig 1c). These core AML-blast genes were linked to significant activation of the Wnt/Ca2+, Phospholipase C, and integrin signaling pathways (Z score 〉2 and P-value

Description: B[ e ] supergiants are a rare and unusual class of massive and luminous stars, characterised by opaque circumstellar envelopes. GG Carinae is a binary whose primary component is a B[ e ] supergiant and whose variability has remained unsatisfactorily explained. Using photometric data from ASAS, OMC, and ASAS-SN, and spectroscopic data from the Global Jet Watch and FEROS to study visible emission lines, we focus on the variability of the system at its ∼31-day orbital period and constrain the stellar parameters of the primary. There is one photometric minimum per orbital period and, in the emission line spectroscopy, we find a correlation between the amplitude of radial velocity variations and the initial energy of the line species. The spectral behaviour is consistent with the emission lines forming in the primary’s wind, with the variable amplitudes between line species being caused by the less energetic lines forming at larger radii on average. By modelling the atmosphere of the primary, we are able to model the radial velocity variations of the wind lines in order to constrain the orbit of the binary. We find that the binary is even more eccentric than previously believed (e = 0.5 ± 0.03). Using this orbital solution, the system is brightest at periastron and dimmest at apastron, and the shape of the photometric variations at the orbital period can be well described by the variable accretion by the secondary of the primary’s wind. We suggest that the evolutionary history of GG Carinae may need to be reevaluated in a binary context.