bluuebunny/crossref_metadata_2025_split huggingface dataset:
Agelastatin A (AgA), a Marine Sponge Derived Alkaloid, Inhibits Wnt/Beta-Catenin Signaling and Selectively Induces Apoptosis in Chronic Lymphocytic Leukemia Independently of p53
Authors: Choi Michael Y. , Cardenas Johanna Melo , Lu Desheng , Yu Jian , Stout E. Paige , Wu Raymond P. , Horton John M , Gomez Allison , Diaz-Perez Julio A. , Carson Dennis A. , Molinski Tadeusz F. , Kipps Thomas J. , Castro Januario E. 
Published: October 2019

Abstract
Abstract 1786
The Wnt/beta-catenin pathway is highly active in chronic lymphocytic leukemia (CLL) and confers an anti-apoptotic effect in vitro and possibly also in vivo. As such, inhibition of this pathway represents a potential therapeutic target.
Here we report preclinical studies using agelastatin A (AgA), a naturally occurring alkaloid extracted from the marine sponges Agelas dendromorpha and Cymbastella sp. We tested AgA using SW480 cells transfected with a beta-catenin dependent reporter gene expression system. Using this assay, we found that AgA is a potent Wnt signaling inhibitor with IC50 of 12nM. AgA also inhibits the expression of reporter genes in HEK293 cells cotransfected with either Wnt1 or mutated (dominant-active) beta-catenin, suggesting that its mechanism of action is independent of the beta-catenin degradation complex. Moreover, real time-PCR results show that Lef1, a classic Wnt/beta-catenin target gene highly expressed in CLL, is down-regulated in primary CLL cells incubated with AgA at nanomolar concentrations.
AgA, but not structurally related compounds agelastatin C and agelastatin D, selectively induces apoptosis in CLL B-cells (mean IC50 = 56nM) compared with peripheral blood mononuclear cells from healthy volunteers (mean IC50 = 250nM). Interestingly, AgA induces apoptosis at nanomolar concentrations even in samples from CLL patients who had no clinical response to fludarabine, samples with 17p deletion or TP53 gene mutations, and samples in which p53 deficiency was determined by in vitro chemoresistance and absence of inducible p21, CD95, and DR5 after irradiation (Figure 1). In addition, AgA induces apoptosis on CLL cells that are maintained in co-culture conditions with stromal cells, which typically increases leukemia cell viability. This suggests that AgA is capable of disrupting pro-survival signals derived from the microenvironment, including Wnt mediated activation.
In conclusion, AgA has potent activity against CLL cells in vitro. Our studies show that AgA inhibits Wnt/beta-catenin signaling at nanomolar concentrations, induces apoptosis in CLL cells independently of p53, and is able to disrupt pro-survival signaling derived from stromal cell support. AgA warrants further studies and clinical development for the treatment of CLL and potentially other malignancies associated with Wnt/beta-catenin signaling.

Disclosures:
No relevant conflicts of interest to declare.
Outcomes of Myeloma Patients on Hemodialysis in the Era of Novel Therapies: An Analysis of the US Renal Data System
Authors: Weiss Brendan M , Hurst Frank , Agodoa Lawrence , Abbott Kevin C 
Published: October 2019

Abstract
Abstract 1803

Background.
Historically, severe renal failure requiring hemodialysis (HD) complicates multiple myeloma (MM) in 2–13% of patients. Recent epidemiologic studies show marked improvements in the survival of MM in the era of autologous transplantation and novel agents (post-1995). It is not clear how these therapies, which are feasible on HD, have affected the outcome of MM patients on HD. We have performed the first study of outcomes of MM patients on HD treated during the era of novel therapies. Methods. Patients who were initiated on dialysis whose primary cause of ESRD was listed as MM between 1989–2008 were included using the US Renal Data System (USRDS) database, which incorporates extensive baseline and follow-up demographic and clinical data on all patients accessing the Medicare ESRD program in the United States. The patients were divided into three time periods based on the introduction of novel therapies: 1989–1994, 1995–2000 and 2001–2008. Survival was calculated using dates of dialysis initiation, death, or end of study period and compared using Cox regression analysis. Results. The characteristics of the patients are shown in the table. After 1995 MM patients initiated on HD were older, had significantly more co-morbidities, poorer functional status and a lower albumin. The patients in 1989–1994 had markedly lower rates of co-morbidities than the general USRDS population. The median survival was 1.77, 0.74 and 0.69 years (p<0.0001) in 198994, 1995–2000, and 2001–2008, respectively. The rates of survival at 1 and 5 years were significantly lower in the two latter time periods. Adjusting for age, hemoglobin, albumin, and co-morbidities, the latter time periods were associated with a HR for death of 3.21 [95% CI 2.18–4.73, p<0.001] and 3.22 [2.18-4.74, p <0.001)], respectively. Conclusions. Patients with MM initiated on HD in the era of novel therapies have significantly more co-morbidities and worse survival. Given the effectiveness of novel therapies, it is likely that MM patients requiring HD in the era of novel therapies represent a population with aggressive, treatment refractory disease for whom alternative approaches are needed. An analysis of therapies delivered to this population is planned.

Disclosures:
No relevant conflicts of interest to declare.
CD34+/CD38− Acute Myelogenous Leukemia Cells Aberrantly Express Aurora Kinase A
Authors: Yang Jing , Ikezoe Takayuki , Furihata Mutsuo , Nishioka Chie , Yokoyama Akihito 
Published: October 2019

Abstract
Abstract 1886
Aurora kinase A (AURKA) plays a pivotal role in the mitotic processes during cell division. We previously showed that AURKA was aberrantly expressed in hematological malignant cells including those from acute myelogenous leukemia (AML) and acute lymphoblastic leukemia, compared with CD34+ hematopoietic stem/progenitor cells isolated from healthy volunteers. This study found that freshly isolated CD34+/CD38− cells from individuals with AML (n=12) in which leukemia stem cells were supposed to be enriched expressed a greater amount of AURKA than their CD34+/CD38+ counterparts, as measured by real time RT-PCR. Blockade of AURKA by the specific inhibitor MLN8237 significantly inhibited proliferation and induced apoptosis of CD34+/CD38− AML cells, as assessed by the clonogenic assay and detection of the cleaved form of poly (ADP-ribose) polymerase by Western blot analysis, respectively. In addition, exposure of CD34+/CD38− AML cells to MLN8237 down-regulated levels of Bcl-2 family proteins and increased Bax/Bcl-2 expression ratio. Moreover, inhibition of AURKA by MLN8237 (30mg/kg for 14 consecutive days) impaired engraftment of CD34+/CD38− AML cells in severely immunocompromised mice (n=5, 49±32% in control vs 18±16% in MLN8237 treated mice, P<0.05), and prolonged their overall survival (P<0.05), compared with vehicle treated mice. Taken together, AURKA may be a promising molecular target to eliminate chemotherapy-resistant CD34+/CD38− AML cells.

Disclosures:
No relevant conflicts of interest to declare.
Janus Kinase-2 Inhibition Induces Durable Tolerance to Alloantigen by Dendritic Cell-Stimulated Human T Cells, Yet Preserves Immunity to Recall Antigen
Authors: Betts Brian C. , Abdel-Wahab Omar , Curran Shane A , St. Angelo Erin T , Koppikar Priya , Heller Glenn , Levine Ross L , Young James W 
Published: October 2019

Abstract
Abstract 1903
Janus kinase 2 (JAK2) conveys signals from receptor binding by several inflammatory cytokines, including IL-6, IL-12, and IL-23, via phosphorylation of signal transducer and activator of transcription 3 (STAT3). These cytokines promote the development and expansion of T helper 1 (Th1) cells, which use IL-12, and Th17 cells, which use IL-6 and IL-23. Th1 and Th17 cells can in turn induce alloreactive end organ damage in GvHD. JAK2 is therefore a principle gatekeeper of alloreactivity and inflammation, and it represents an attractive target to control GvHD. We demonstrate that TG101348, a synthetic small molecule, highly selective JAK2 inhibitor, when present during initial and secondary encounters between human T cells and allogeneic monocyte-derived dendritic cells (moDCs), induces durable, profound, and specific T cell tolerance on reexposure to the same alloantigens. TG101348 ablates IL-6/JAK2-mediated phosphorylation of STAT3 in T cells (24% v 0%, P<0.05, n=5) but has no off-target effects on IL-2 or IL-15/JAK3/pSTAT5-dependent signaling, which would interfere with Tregs and other effector T cell responses. JAK2 inhibition preserves Treg numbers and thereby enhances the ratio of CD4+ Tregs to CD8+CD25+ effector T cells in favor of Tregs (Treg:Effector 1:2 vs 1:1, P<0.05, n=5). JAK2 inhibition also reduces the production of IL-6 (255 vs 157 pg/ml, P<0.05, n=5) and TNF-alpha (50 vs 15 pg/ml, P<0.05, n=4) in allogeneic MLRs, impairing the activation of central and effector memory T cells as well as the expansion of responder Th1 (24% vs 14%, P<0.05, n=4) and Th17 (2% vs 1%, P<0.05, n=4). T cells, stimulated by moDCs in the presence of TG101348, demonstrate a marked reduction in proliferative capacity upon reexposure to fresh allogeneic moDCs from the original stimulating party, even in the absence of the JAK2 inhibitor during the secondary MLR (P<0.05, n=4). Responses to stimulation de novo by influenza matrix peptide (fluMP), a pathogenic nominal antigen, remain intact (P=NS, n=4). Conversely, TG101348 also inhibits secondary MLR responses by T cells, which have already been sensitized to alloantigens in a primary MLR without the JAK2 inhibitor (P<0.05, n=4). The durable tolerance against full HLA disparities in each of these settings provides preclinical data in vitro that JAK2 represents a relevant biologic target for preventing or treating graft-versus-host disease (GvHD), or even solid organ allograft rejection, without broader immune impairment.

Disclosures:
No relevant conflicts of interest to declare.
Effect of Plerixafor on Graft Lymphocyte Subsets in NHL Patients Mobilizing Poorly with Chemotherapy Plus G-CSF
Authors: Jantunen Esa , Varmavuo Ville , Kuittinen Taru , Nousiainen Tapio , Mäntymaa Pentti 
Published: October 2019

Abstract
Abstract 1929
A combination of chemotherapy plus G-CSF (chemomobilization) is commonly used to mobilize CD34+ cells to circulation. Mobilization of CD34+ cells is poor or suboptimal in 20–30 % of patients. Plerixafor, a CXCR4 antagonist, increases the mobilization of CD34+ cells and may also have effect on graft composition subsequently collected. There are no data on lymphocyte subsets in the grafts collected after chemomobilization plus pre-emptively given plerixafor.
We have analyzed lymphocyte subsets (CD3, CD4, CD8, NK cells, CD19) in grafts collected on the next morning after plerixafor injection in 13 chemomobilized patients with non-Hodgkin lymphoma. As controls we had the first collections from 13 NHL patients mobilized with chemotherapy plus G-CSF and with yield of 2–6 × 106/kg CD34+ cells with 1–2 aphaereses.
The median CD34+ content of the analyzed grafts was 1.45 × 106/kg in the plerixafor group compared to 1.8 × 106/kg in the controls (p=n.s.). The number of T-cell subsets and NK cells were significantly higher in plerixafor mobilized grafts (Table 1). CD19+ B cells were infrequent in both groups.Table 1.Lymphocyte subsets of the grafts.Stem cell collection with plerixafor, median (range)Stem cell collection without plerixafor, median (range)Significance pGraft volume (ml)100 (43–190)80 (45–140)0.280Graft sample preservation time (days)299 (31–450)291 (103–397)0.898CD34+ cell content (x 106/ kg) after 7-AAD1.45 (0.40–4.40)1.80 (0.31–4.74)0.858CD3+ cell content (x 106/kg)75.3 (14.6–327.3)21.3 (9.1–159.4)0.004CD4+ cell content (x 106/kg)32.7 (10.6–132.8)12.4 (6.9–51.5)0.002CD8+ cell content (x 106/kg)33.4 (4.2–200.5)8.8 (2.2–125.0)0.006CD19+ cell content (x 106/kg)0 (0–0)0 (0–0)NANK cell content (x 106/kg)5.1 (0.2–30.40)1.5 (0.3–8.0)0.045CD4+/CD8+ cell ratio0.98 (0.34–3.04)1.41 (0.28–5.06)0.2287-AAD, 7-Aminoactinomycin D; NK, natural killer.
All except one patient has received high-dose therapy with blood stem cell support. The median CD34+ cell dose was 3.1 × 106/kg in plerixafor treated group and 3.3 × 106/kg in the control group, respectively. Time to neutrophil engraftment was comparable between the groups. There were two patients in the plerixafor group with late platelet engraftment (1 and 6 months).
Addition of plerixafor to chemomobilization in poor mobilizers results in increased content of T lymphocytes and NK cells in the graft but do not appear to mobilize B lymphocytes. Whether higher T cell and NK cell content are associated with more rapid immune reconstitution and survival should be evaluated in larger patient series with longer follow-up.

Disclosures:
Jantunen: Genzyme: Honoraria. Kuittinen:Roche: Consultancy.
A Phase 1 Open Label, Dose Escalation Study of Nilotinib in Steroid Dependent/Refractory Chronic Graft-Versus-Host Disease
Authors: Chen George L. , Carpenter Paul A. , Broady Raewyn , Gregory Tara B. , Arai Sally , Johnston Laura , Flowers Mary E.D. , Beumer Jan H. , Mendolsohn Jodie , Zhou Xin , Perloff Spenser H. , Otani Joanne M , Miklos David B 
Published: October 2019

Abstract
Abstract 1986
Imatinib is clinically active in cGvHD. Nilotinib, a tyrosine kinase inhibitor, targets the same receptors as imatinib but with different affinities. These targets and their IC50s are: DDR1 3.7 nM, DDR2 5.2 nM, ABL 25 nM, PDGFRA 53 nM, KIT 158 nM, and NQO2 1800 nM. We hypothesized that nilotinib is safe, tolerable, and clinically efficacious in cGvHD. We present preliminary safety and pharmacokinetic data from a phase 1 trial of nilotinib for steroid dependent/refractory cGvHD.

Methods.
All subjects had extensive steroid dependent/refractory cGVHD treated previously with ≥ 2 agents. Previous treatment with imatinib was allowed. Steroid refractory was defined as progressive cGVHD despite prednisone ≥ 0.5 mg/kg/d for ≥ 1 month; steroid dependence was cGVHD requiring prednisone ≥0.25 mg/kg/d for ≥ 3 months. This was a dose escalation trial with 4 sequential dose levels: 200 mg daily, 200 mg twice daily, 400 mg daily, and 400 mg twice daily followed by a dose extension phase at the maximum tolerated dose (MTD). Enrollment followed a standard 3+3 design. Steroids and two other immunosuppressants were allowed. Steroids were tapered as tolerated and other immunosuppressant dosing remained constant. Safety was determined by the observation of adverse events graded according to CTCAE v. 4.0 criteria. Trough plasma nilotinib concentrations were determined by HPLC before the daytime day 8 dose.

Results.
Median age was 49 years (range 23–75). Mean time to study enrollment from transplant was 3.3 years (range 1.7–7.8) and from cGVHD diagnosis 2.9 years (range 0.4–6.6). Sixteen subjects have been enrolled and 14 are evaluable. The median follow-up is 4.5 months (range 0.1–8.0). The MTD was reached at 200 mg daily. The maximum administered dose (MAD) was 200 mg twice daily. The dose limiting toxicities (DLTs) were grade 3 Pneumocystis pneumonia and grade 3 asymptomatic lipase elevation. Grade 2–3 adverse events possibly/probably attributed to nilotinib are shown below; no grade 4–5 adverse events attributed to nilotinib have occurred to date. Median trough plasma concentration of nilotinib 1 week after drug initiation at the MTD was 997 nM (range 661–1380, n=3) and at the MAD was 3110 nM (range 1210–4200, n=3). Trough nilotinib concentrations were higher at the MAD and were associated with DLT occurrence.

Conclusions.
200 mg daily is the MTD in the cGvHD population. Safety and clinical effect at the MTD is being evaluated in an ongoing 35 subject extension study. The MTD results in a trough plasma concentration that may be adequate to inhibit the nilotinib receptor targets except for NQO2. Confirmatory pharmacodynamic studies are planned.

Disclosures:
Off Label Use: Nilotinib for treatment of chronic graft versus host disease.
Modification of An Interactive Surface in the C1 Domain Reduces Immune Responses to FVIII in a Mouse Model of Hemophilia A
Authors: Wroblewska Aleksandra , van Haren Simon D , Herczenik Eszter , Rusiecka Aleksandra , Kaijen Paul H , ten Brinke Anja , Mertens Koen , Voorberg Jan 
Published: October 2019

Abstract
Abstract 199FN2
The X-chromosome-linked bleeding disorder hemophilia A is caused by the absence or dysfunction of blood coagulation factor VIII (FVIII) which can be corrected by regular intravenous administration of FVIII. Development of antibodies directed against FVIII (referred to as FVIII inhibitors) is common complication in hemophilia care. The formation of FVIII-neutralizing antibodies in hemophilia A patients is initiated by the endocytosis of FVIII by professional antigen-presenting cells. Endocytosis of FVIII by human monocyte-derived dendritic cells can be significantly blocked by monoclonal antibody KM33, directed towards the C1 domain of FVIII. We have previously shown that C1 domain residues 2092 and 2093 are required for KM33 binding to FVIII (Meems et al., 2009). However, replacement of both these residues by Ala did not completely abolish KM33 binding. We created an additional C1 domain variant which included an arginine at position 2090. A FVIII variant in which three residues, 2090, 2092 and 2093 were substituted by alanine, showed only minimal binding to KM33. Functional analysis revealed that this variant designated FVIII-2090/2092/2093 retains pro-coagulant activity as measured by a chromogenic assay. FVIII-2090/2092/2093 displayed a strongly reduced internalization by human monocyte-derived dendritic cells and macrophages, as well as murine bone marrow-derived dendritic cells. These results emphasize a role for C1 domain residues 2090, 2092 and 2093 in FVIII endocytosis by antigen-presenting cells. We subsequently investigated the in vivo ability of this variant to induce inhibitors in FVIII−/− mice (E17KO). We show that E17KO mice treated with the FVIII variant have significantly lower anti-FVIII antibody titers when compared to mice treated with wild type FVIII. In accordance with these findings reduced numbers of FVIII-specific antibody-secreting cells were detected in the spleen of mice treated with FVIII-2090/2092/2093. Also, FVIII-specific CD4+ T cell responses of splenocytes derived from FVIII-2090/2092/2093 infused mice were greatly reduced when compared to that of splenocytes derived from wild type FVIII infused mice. These findings show that alanine substitutions at positions 2090, 2092 and 2093 result in a FVIII molecule that is significantly less immunogenic when compared to wild type FVIII. Collectively, our data suggest that FVIII variants displaying a reduced uptake by antigen-presenting cells show a reduced immunogenicity in vivo. Based on our findings we hypothesize that FVIII variants displaying a reduced uptake by antigen-presenting cells provide a novel therapeutic approach to reduce inhibitor development in patients with hemophilia A.

Disclosures:
No relevant conflicts of interest to declare.
A Retrospective Observational Study of Annual Healthcare Costs for Patients with Forms of Myeloproliferative Neoplasms (MPN)
Authors: Price Gregory L , Pohl Gerhardt M , Xie Jin , Walgren Richard A 
Published: October 2019

Abstract
Abstract 2060

Background:
Three subtypes of MPN (myelofibrosis (MF), polycythemia vera (PV) and essential thrombocythemia (ET)) are characterized by activation of JAK2 signaling, with the majority having the JAK2 V617F mutation. Median survival in these subtypes ranges from months to years for MF (Gangat JCO 2011) and up to a decade or more for some patients with PV and ET. Some symptomatic treatment options exist, but with the exception of hematopoietic stem cell transplant, none are curative. Little is known about healthcare costs associated with these diseases.

Objective:
To compare annual medical and pharmacy costs in three subtypes of MPN patients (MF, PV, ET) to matched non-cancer controls using a large US commercial claims database.

Methods:
Data were drawn from the Thomson Reuters MarketScan database, which contains claims for insured employees, retirees and dependents from approximately 100 US payers. Index date was the first claim with an MPN diagnosis code in the time period 2005 to 2008. Eligible patients had one year continuous enrollment post-index with no evidence of non-AML secondary malignancy. Controls had one year of continuous enrollment after their match date and were matched to patients in a ratio of 5:1 based on gender, year of birth, geographic region and insurance type (Comprehensive, Health Maintenance Organization, Preferred Provider Organization, etc.). Controls were excluded if they had a service claim with a diagnosis for cancer or a pharmacy claim for chemotherapy. Costs were based on total gross payments to the provider, which equals the amount eligible for payment under the medical plan terms after applying rules for discounts, but before applying coordination of benefits, copayments and deductibles. Total cost was the sum of MPN and non-MPN related medical costs which included inpatient, outpatient and emergency room service and pharmacy. Pharmacy included injectable and non-injectable chemotherapy, supportive care and other prescription drug costs.

Results:
A total of 25,145 MPN patients (MF: 509, PV: 16,165, ET: 8,471) were included and assigned matching controls. The mean cost (standard deviation) for cases and controls are shown in the table.
Medical and Pharmacy Costs:

Conclusions:
Annual medical and pharmaceutical costs for patients with MPNs are 2 to 6 times those of matched non-cancer patients and represent medical management challenges and payer burden. Outpatient visits accounted for about half of the total healthcare costs, followed by inpatient visits, pharmaceutical costs and ER visits.

Disclosures:
Price: Elil Lilly and Company: Employment; Eli Lilly and Company: Equity Ownership. Pohl:Eli Lilly and Company: Employment; Eli Lilly and Company: Equity Ownership. Xie:Eli Lilly and Company: Employment; Eli Lilly and Company: Equity Ownership. Walgren:Eli Lilly and Company: Employment; Eli Lilly and Company: Equity Ownership.