Citations

AbstractBackgroundMeasuring changes in the earliest phases of familial frontotemporal lobar degeneration (f‐FTLD) and estimating symptom onset has important implications for clinical care. Early stage clinical trials have begun for f‐FTD, but the low prevalence of f‐FTLD mutation carriers and heterogeneous symptomology challenges trial design. Bayesian disease progression models (DPM) incorporate clinical data, neuroimaging metrics, and fluid biomarker concentrations to estimate latent disease age, providing estimates of symptom onset and progression status. Such models may facilitate enrollment in studies (i.e., inclusion of presymptomatic individuals) and provide more powerful analysis methods for trials.MethodA Bayesian latent variable repeated measures model was used to estimate disease progression, conditional on latent disease age (proximity to symptom onset), in 275 participants with mutations in GRN (n=68), MAPT (n=80) and C9orf72 (n=127). Median follow‐up was one year (range: 0‐4). Jointly modeled longitudinal variables included neuropsychological scores, CDR®+NACC‐FTLD box score, 3T MRI frontotemporal brain volumes, and plasma levels of neurofilament light chain (NfL). Sample size estimates for detecting treatment effects were generated by varying thresholds of estimated proximity to symptom onset.ResultThe Bayesian DPM provided a clear picture of clinical and neurological progression within each mutation group. Neuroimaging and NfL captured early progression rates (1 SD from controls) 5‐10 years before symptom onset. After symptom onset, CDR®+NACC‐FTLD box score was the most sensitive measure of disease progression. GRN mutation carriers had the largest annual progression rates (and lowest variability) compared to MAPT and C9orf72. Between 5 years pre‐ and 10 years post‐onset, CDR®+NACC‐FTLD box score progressed by 2 units/year (SD=2.7) in GRN mutation carriers ‐ almost twice the rate of progression in MAPT (M=1.2;SD=2.5) and C9orf72 (M=1.1;SD=2.2) mutation carriers. Compared to a trial enrolling only early symptomatic cases (CDR®+NACC‐FTLD=0.5 or 1), utilizing latent disease age would facilitate enrollment of asymptomatic cases with the same power.ConclusionBased on an estimation of symptom onset, Bayesian DPMs suggest clinical trials in GRN mutation carriers would require the smallest sample sizes. Furthermore, leveraging these DPMs would allow novel, powerful trial designs that may facilitate greater participant enrollment.

CMML is a lethal myeloid neoplasm with no therapies that improve its dismal prognosis. Inhibition of BET family members has been proposed as a therapeutic strategy based on preclinical data identifying BRD4 as a therapeutic target in acute myeloid leukemia. However, despite potent on-target transcriptional remodeling, early phase clinical trials have demonstrated only modest activity secondary to a variety of resistance mechanisms. In ovarian cancer BET inhibitor (BETi) treated cells, compensatory upregulation and addiction to pro-survival kinase networks have been observed. Given that over 50% of CMML cases have mutations upregulating kinase signaling, we hypothesized that BETi resistance is mediated by these networks in CMML and can be targeted therapeutically. We tested this hypothesis by performing a limited screen of kinase inhibitors alone and in combination with the IC20 of the BETi INCB54329 in 8 human leukemia cell lines. This screen revealed that the IC50 of the PIM inhibitor (PIMi) INCB53914 decreased after co-treatment with BETi in a majority of the leukemia cell lines tested. Synergy was validated chemically in U937, TF1 and SKM1 leukemia cells using other selective inhibitors of BET and PIM. We next assessed the activity of the BET-PIM combination in 14-day colony formation assays with 10 unique CMML bone marrow mononuclear cell (BM-MNCs) patient samples(Fig. 1A). These studies revealed that combination therapy significantly suppressed clonogenicity versus BMNCs treated with vehicle or single drug alone. Finally, this synergy was validated in vivo in 36 patient derived xenografts (PDX) from 3 CMML patients, as manifest by reduced leukemic burden/engraftment in CMML PDX treated with combination therapy(Fig. 1B). To explore the mechanism by which BETi and PIMi therapeutically synergize we treated U937 and SKM1 leukemia cells with INCB54329 and measured mRNA and protein levels for all PIM isoforms. Surprisingly, we identified that PIM1 was increased following treatment with INCB54329, other BETi, or a JQ1-derived PROTAC (Fig. 1C). PIM1 upregulation was also manifest in INCB54329 persistor U937 leukemia cells generated by daily BETi treatment for 6 weeks. Testing across a broader panel of leukemia cell lines revealed an inverse correlation between PIM1 induction and decrease in the IC50 of PIMi following BETi treatment, suggesting PIM1 upregulation confers sensitivity to combination therapy. Consistent with this, isogenic SKM1 leukemia cells engineered to overexpress PIM1 were resistant to INCB54329 and were more sensitive to INCB53914 versus controls cells. Recent studies have demonstrated that inhibitory miRNAs, especially those located near super-enhancers, are suppressed by BET inhibition. Given that several miRNAs are known to control PIM1 expression, we hypothesized that paradoxical PIM1 upregulation following BETi treatment was due to down-regulation of select miRNAs. To test this, we treated our leukemia cell models with broad inhibitors of miRNA activity (i.e., AGO and Dicer inhibitors) and observed a dose dependent increase in PIM1 levels similar to that seen with BET inhibition(Fig. 1Di). Further, integrating public H3K27 CHIP-seq and miRNA super enhancer datasets and using computational prediction algorithms, we identified 6 candidate miRNAs that could regulate PIM1 and were predicted to be controlled by BET inhibitors. Of these, only miR-33a levels were reduced in a dose dependent manner in SKM1 cells by BETi treatment(Fig. 1Dii). This was confirmed by genetically silencing all BET proteins, which suppressed miR-33a levels in SKM1 leukemia cells. Finally, miR-33a mimics (but not control miRNAs) abolished BETi-induced upregulation of PIM1(Fig. 1Diii). Collectively, these studies established BET and PIM inhibition as a novel and potent combination therapy for CMML that is mediated by miR-33a-dependent upregulation of PIM1(Fig. 1E). Disclosures Liu: Incyte Corporation: Employment. Patnaik:Stem Line Pharmaceuticals.: Membership on an entity's Board of Directors or advisory committees. Lancet:Daiichi Sankyo: Consultancy, Other: fees for non-CME/CE services ; Agios, Biopath, Biosight, Boehringer Inglheim, Celator, Celgene, Janssen, Jazz Pharmaceuticals, Karyopharm, Novartis: Consultancy; Pfizer: Consultancy, Research Funding. Komrokji:Novartis: Speakers Bureau; JAZZ: Speakers Bureau; JAZZ: Consultancy; Agios: Consultancy; Incyte: Consultancy; DSI: Consultancy; pfizer: Consultancy; celgene: Consultancy. Epling-Burnette:Incyte Corporation: Research Funding. List:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Haura:Incyte Corporation: Research Funding. Reuther:Incyte Corporation: Research Funding. Koblish:Incyte Corporation: Employment.

Abstract Abstract 4723 Introduction: Combination G/A has been shown to be apromising investigational therapy for patients with metastatic pancreatic cancer. A randomized phase II trial was initiated to determine if ODSH, a low anticoagulant heparin derivative that blocks several pancreatic cancer cell survival pathways, would enhance the efficacy of G/A. Preliminary data from the first 10 patients administered ODSH demonstrated an unexpected and profound preservation of peripheral blood counts, despite the highly myelosuppressive G/A regimen they also received. Methods: Patients with previously untreated, metastatic pancreatic cancer were treated with G (1000 mg/m2) and A (125 mg/m2) on days 1, 8, and 15 every 28 days until either disease progression or unacceptable toxicities ensued. ODSH (4 mg/kg bolus followed by a 48 hr. continuous IV infusion at a dose of 0.375 mg/kg/hr for 48 hrs) was administered with each treatment. The first 10 patients received A/G plusODSH with plans for a randomized comparison between A/G with and without ODSH involving 50 patients. Patients were required to have ECOG 0–1 as well as adequate hematological and bilirubin level <1.5 ULN. G-CSF administration was permitted per investigator discretion. Here we present hematological data on the 10 patients treated with A/G plus ODSH. Results: 10 patients were administered up to 5 cycles of G/A plus ODSH. The patients had a median age of 66 years (range, 59 to 75 years) and 50% were male. The median platelet and neutrophil counts prior to each cycle are listed in Table 1. No patients had grade 3/4 thrombocytopenia during any of the cycles. Forty percent of patients had grade 3 neutropenia, but none had grade 4 during any of the cycles. Only 1 patient received 1 dose of G-CSF after day 15 in cycle #1. Conclusions: A previous trial of G/A in patients with previously untreated, metastatic pancreatic cancer reported grade 3/4 thrombocytopenia and neutropenia in 28% (19% grade 3 and 9% grade 4) and 75% (26% grade 3 and 49% grade 4) of patients, respectively (Von Hoff, J Clin Oncol, 2011). With the addition of ODSH to an equivalent chemotherapy regimen in a similar patient cohort, the current trial reported grade 3 thrombocytopenia and neutropenia in 0% and 40% of patients, respectively, with no patients having grade 4 thrombocytopenia or neutropenia. With successive cycles, median platelet counts were stable to improved and a trend existed for reduced neutropenia with ODSH treatment. An explanation for the apparent salutary effects of ODSH on marrow function may involve its interaction with platelet factor 4 (PF4). PF4 is released from the alpha-granules of injured megakaryocytes after chemotherapy delivery. Increased PF4 levels promote thrombocytopenia by inhibiting thrombopoietin production and megakaryopoiesis (Lambert, Blood, 2007; Lambert, Int J Radiation Oncology Biol Phys, 2011). The high molecular weight and strong negative charge of ODSH may result in avid binding to platelet factor 4 (PF4), possibly leading to decreased PF4 levels and more rapid post-chemotherapy platelet recovery (Joglekar, Thromb Haemost, 2012). PF4 may also facilitate neutrophil adhesion to endothelial cells, and reduced PF4 levels from ODSH binding may demarginate and preserve neutrophil values (Kasper, Blood, 2006). Further study of ODSH as a marrow protective agent in myelosuppressivechemotherapy regimens is warranted. Disclosures: Off Label Use: The use of nab-paclitaxel and ODSH in pancreatic cancer. Marcus:Paringenix: Employment, Equity Ownership. Quintana Diez:Paringenix, Inc.: Employment.

Mechanical ventilation is necessary to support patients with acute lung injury, but also exacerbates injury through mechanical stress–activated signaling pathways. We show that stretch applied to cultured human cells, and to mouse lungs in vivo, induces robust expression of metallothionein, a potent antioxidant and cytoprotective molecule critical for cellular zinc homeostasis. Furthermore, genetic deficiency of murine metallothionein genes exacerbated lung injury caused by high tidal volume mechanical ventilation, identifying an adaptive role for these genes in limiting lung injury. Stretch induction of metallothionein required zinc and the zinc-binding transcription factor MTF1. We further show that mouse dietary zinc deficiency potentiates ventilator-induced lung injury, and that plasma zinc levels are significantly reduced in human patients who go on to develop acute respiratory distress syndrome (ARDS) compared with healthy and non-ARDS intensive care unit (ICU) controls, as well as with other ICU patients without ARDS. Taken together, our findings identify a potentially novel adaptive response of the lung to stretch and a critical role for zinc in defining the lung’s tolerance for mechanical ventilation. These results demonstrate that failure of stretch-adaptive responses play an important role in exacerbating mechanical ventilator–induced lung injury, and identify zinc and metallothionein as targets for lung-protective interventions in patients requiring mechanical ventilation.

284 Background: ODSH, a low anticoagulant heparin derivative, interferes with several important pancreatic cancer cell survival pathways. A randomized phase II trial was initiated to determine if ODSH improves the activity of G/A, a promising pancreatic cancer investigational therapy. Preliminary data are presented here for the first 10 patients administered ODSH as part of an initial run-in phase prior to patient randomization. Methods: Patients with previously untreated, metastatic pancreatic cancer were treated with G (1,000 mg/m2) and A (125 mg/m2) plus ODSH (4 mg/kg bolus followed by a 48 hr. continuous IV infusion at a dose of 0.375 mg/kg/hr) on days 1, 8, and 15 every 28 days until disease progression or unacceptable toxicity. Patients were required to have ECOG ≤ 1 and appropriate blood and liver function levels. The primary endpoint was progression-free survival (PFS). Results: 10 patients (median age, 66 years) were administered up to 5 cycles of G/A plus ODSH. Per RECIST criteria, a partial response (PR) was achieved in 5 patients (50%) and the median PFS will exceed 6 months. Disease control (PR or stable disease for > 16 weeks) occurred in all 10 patients. Of 9 patients with baseline elevated CA 19-9 levels, 8 had > 60% reduction. ODSH was well tolerated and unexpectedly appeared to preserve marrow function as no patients had grade 3/4 thrombocytopenia or grade 4 neutropenia during any of the cycles. Conclusions: Although G/A and FOLFIRINOX are important advances, additional progress is necessary for metastatic pancreatic cancer patients. ODSH may interfere with pancreatic cancer invasion, metastasis, and chemo-resistance by inhibiting P- and L-selectins, heparanase, and the HMGB1-RAGE axis, respectively, suggesting that ODSH may enhance chemotherapy activity. This preliminary analysis in a small number of patients is encouraging and consistent with a previous report for this regimen (Von Hoff, J Clin Oncol, 2011). ODSH has also been very well tolerated and early data suggests that it may preserve platelet and neutrophil levels. Further follow-up of the ongoing randomized phase II trial is warranted. Clinical trial information: NCT01461915.

Introduction: Prior studies (predominantly from Europe) have demonstrated blood culture-negative endocarditis due to Bartonella. Our objective was to describe three cases of Bartonella quintana endocarditis identified within one year at a large hospital in Washington, DC, USA. Case presentation: We constructed a descriptive case series from a retrospective review of medical records from April to December 2013 at an 800-bed urban hospital. All three patients (ages: 52, 55 and 57 years) were undomiciled/homeless men with a history of alcoholism. Although they had negative blood cultures, echocardiography demonstrated aortic/mitral valve perforation and regurgitation in one patient, aortic/mitral valve vegetation with mitral regurgitation in the second patient, and aortic valve vegetation with regurgitation in the third patient. The patients had positive Bartonella quintana serum immunoglobulin G (IgG) with negative immunoglobulin M (IgM). PCR on DNA extracted from cardiac valves was positive for Bartonella, and DNA sequencing of PCR amplicons identified Bartonella quintana. Patients received treatment with doxycycline/rifampin or doxycycline/gentamicin. Conclusion: Clinicians should consider Bartonella endocarditis as a differential diagnosis in patients who fit elements of the Duke Criteria, as well as having a history of homelessness and alcoholism.

Exposure of the basal and midventricular septum through the aortic root to relieve obstruction in hypertrophic cardiomyopathy can be challenging. Inadequate myectomy will lead to persistent symptoms and disability. Adequate exposure of the obstructive left ventricular septum is of paramount importance in primary and redo myectomy. In selected patients, either at primary myectomy or at redo myectomy, septal excision can be approached through a left ventricular transapical incision when transaortic exposure is inadequate.