Citations

7547 Background: E1412 statistical design is based on results of lenalidomide/RCHOP (R2CHOP) vs RCHOP in ABC-DLBCL as determined by NanoString gene expression profiling (GEP). Central pathology review (CPR) was conducted to confirm diagnosis and to ensure adequate tissue for GEP. Initially, CPR occurred after randomization and treatment initiation. Due to high ineligibility rate (IR), the protocol was amended to include real-time CPR to determine patient eligibility prior to study enrollment. We describe the revision and how it affected the IR. Methods: Pre-amendment, CPR was done retrospectively. Post-amendment, CPR was done prior to enrollment, in real time, on a submitted tissue block, H&E, and CD20 slides. Based on CPR, if a diagnosis of DLBCL was confirmed, and sufficient tissue remained for GEP, a patient was deemed eligible and the submitter was notified by fax. Protocol goal was notification within 2 working days (WD) of receipt of materials at the CPR site. Results: Pre-amendment, 219 patients were enrolled. Material was typically received at the CPR site 6-9 months after patient registration. The IR with CPR was 36% for all those enrolled, and 26% for patients with adequate tissue for GEP. Post-amendment, 218 patients were submitted for CPR: 145 (67%) were eligible; 73 (33%) were ineligible. Reasons for ineligibility included insufficient tissue (n=27) or a diagnosis other than de novo DLBCL (n=46). Notification of eligibility occurred in a median of 2 WD (Mean 2 WD; Range 1-5 WD). 90% were notified within the protocol goal of 2 WD. GEP for all enrolled was completed within 6 weeks of CPR. Conclusions: The success of this novel, real-time CPR serves as a model for the future of NCTN DLBCL trials. When CPR is performed rapidly prior to enrollment, study slots may more accurately reflect the target population and eliminate excess costs. In the precision medicine era, rapid collection of relevant pathology and biomarker data is essential to trial success. Study Coordinated by ECOG-ACRIN Cancer Research Group (Robert L. Comis, MD and Mitchell D. Schnall, MD, PhD, Group Co-Chairs), supported by NCI grant # CA180820, CA180794, CA180790, CA180799, CA180833.

e15641 Background: CC pts with biliary stents or catheters are prone to have obstruction/infection and studies show 20-40% present with fever/or jaundice requiring urgent treatment for which there is no uniform guideline. We aimed to develop an expert panel consensus on this topic using the modified RAND/UCLA Delphi process to rate treatment appropriateness. Methods: We recruited 13 physician experts from relevant specialty, geography, and practice settings. Patient scenarios were developed and panelists rated the therapies before and after a face-to-face discussion. The appropriateness of various therapies was rated on a 1-9 scale and classified as appropriate, inappropriate, or uncertain. Scenarios with > 2 ratings of 1-3 (inappropriate) and > 2 ratings of 7-9 (appropriate) were considered to have disagreement and were not assigned an appropriateness rating. Results: Panelists were from all US regions (92%) and the UK (8%); had practiced for a mean 16.5 years (4-33 years). Panelists rated 480 scenarios before the meeting, but re-rated only 288 clinical scenarios as they felt that ongoing treatment with chemotherapy did not influence decision-making. Disagreement decreased from 37.5% before the meeting to 10.4% after. Consensus statements are summarized in the table below. Conclusions: The Delphi process produced consensus guidelines to fill an unmet need in urgent management of ascending cholangitis in pts with CC. (Support: The Cholangiocarcinoma Foundation). [Table: see text]

Abstract Castleman disease (CD) describes a group of heterogeneous hematologic disorders with characteristic histopathological features. CD can present with unicentric or multicentric (MCD) regions of lymph node enlargement. Some cases of MCD are caused by human herpesvirus-8 (HHV-8), whereas others are HHV-8–negative/idiopathic (iMCD). Treatment of iMCD is challenging, and outcomes can be poor because no uniform treatment guidelines exist, few systematic studies have been conducted, and no agreed upon response criteria have been described. The purpose of this paper is to establish consensus, evidence-based treatment guidelines based on the severity of iMCD to improve outcomes. An international Working Group of 42 experts from 10 countries was convened by the Castleman Disease Collaborative Network to establish consensus guidelines for the management of iMCD based on published literature, review of treatment effectiveness for 344 cases, and expert opinion. The anti–interleukin-6 monoclonal antibody siltuximab (or tocilizumab, if siltuximab is not available) with or without corticosteroids is the preferred first-line therapy for iMCD. In the most severe cases, adjuvant combination chemotherapy is recommended. Additional agents are recommended, tailored by disease severity, as second- and third-line therapies for treatment failures. Response criteria were formulated to facilitate the evaluation of treatment failure or success. These guidelines should help treating physicians to stratify patients based on disease severity in order to select the best available therapeutic option. An international registry for patients with CD (ACCELERATE, #NCT02817997) was established in October 2016 to collect patient outcomes to increase the evidence base for selection of therapies in the future.

There is considerable interest in harnessing innate immunity to treat Alzheimer’s disease (AD). Here, we explore whether a decoy receptor strategy using the ectodomain of select TLRs has therapeutic potential in AD. AAV-mediated expression of human TLR5 ectodomain (sTLR5) alone or fused to human IgG4 Fc (sTLR5Fc) results in robust attenuation of amyloid β (Aβ) accumulation in a mouse model of Alzheimer-type Aβ pathology. sTLR5Fc binds to oligomeric and fibrillar Aβ with high affinity, forms complexes with Aβ, and blocks Aβ toxicity. Oligomeric and fibrillar Aβ modulates flagellin-mediated activation of human TLR5 but does not, by itself, activate TLR5 signaling. Genetic analysis shows that rare protein coding variants in human TLR5 may be associated with a reduced risk of AD. Further, transcriptome analysis shows altered TLR gene expression in human AD. Collectively, our data suggest that TLR5 decoy receptor–based biologics represent a novel and safe Aβ-selective class of biotherapy in AD.

Abstract Lung cancer has the highest mortality across all cancers in the world. Epidermal growth factor receptor (EGFR) is commonly mutated in lung adenocarcinomas from Asian non-smoking females. These tumors usually respond to EGFR tyrosine kinase inhibitors (EGFR-TKI), but the outcomes vary in different patients. Though EGFR T790M, amplification of MET and other mechanisms have been shown to confer EGFR-TKI resistance, the molecular mechanisms in around 30% of patients are still unknown. To uncover novel candidate pathways of EGFR-TKI resistance, we analyzed the whole exome mutation profiles of pre-treatment, EGFR T790M-free lung adenocarcinomas with typical activating mutations (L858R, exon 19 deletions). Amongst 19 non-responding (NR) tumors without significant shrinkage after gefitinib or erlotinib treatment, 67 cancer-related genes showed coding region non-synonymous single nucleotide variations (SNV) or insertion-deletions (indels) but they were not detected in 22 responding tumors. Gene set enrichment analysis (GSEA) showed 14 of the 67 genes were involved in the EGFR and WNT signaling network (false discovery rate q=1.14 e-8 for EGFR and q=4.3 e-9 for WNT), including well-known TKI resistance-related genes PIK3CA, PTEN and NF1. Notably, ARID1A, which encodes a subunit of the chromatin remodeling complex, showed nonsense mutations in 2 NR but not responding tumors, which were validated by Sanger sequencing. More than 40% of ARID1A mutations in lung adenocarcinomas recorded in COSMIC were nonsense mutations or frameshift indels. Loss of function mutations of ARID1A have also been reported in various cancers, together suggesting ARID1A might be a tumor suppressor but its involvement in EGFR mutant lung cancers is unknown. To investigate the potential role of ARID1A, its expression was first studied using Kaplan-Meier plotter. Low expression of ARID1A is associated with significantly better overall survival than high expression level in lung adenocarcinoma patients (p=8.5 e-7). To test whether loss of ARID1A could cause TKI resistance, ARID1A was knocked down by shRNA in HCC827 lung cancer cell line harboring EGFR exon19 deletion. MTT cell viability assay using gefitinib showed increase of IC50. Western blot assay further showed ARID1A knockdown increased phosphorylation of AKT at Ser473. Together, the findings suggest loss of ARID1A could lead to EGFR bypass and promote activation of the downstream PI3K/AKT pathway, leading to EGFR TKI resistance. Overall, our findings suggest EGFR-TKI resistance mutations could be detected before TKI drug selection. Resistant gene mutations present in pre-treatment tumors could help to predict the treatment response. More specifically, our study identified a promising gene list involved in EGFR-TKI resistance, and suggested ARID1A loss could be a novel EGFR-TKI resistance mechanism. Citation Format: Xuyuan Gao, Hang Xu, James CM Ho, Oscar SH Chan, Feng Xu, Junwen Wang, Victor HF Lee, Vicky PC Tin, Zhijie Xiao, Siqi Wang, Judy WP Yam, Maria P Wong. EGFR-mutant lung adenocarcinomas mutation profiles reveal ARID1A might be a novel tyrosine kinase resistance pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-196.

Aims: Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disease thought to be caused by repetitive traumatic brain injury (TBI) and subconcussive injuries. While hyperphosphorylation of tau (p-Tau), which is attributed to astrocytic tangles (ATs) and neurofibrillary tangles, is known to be involved in CTE, there are limited neuropathological or molecular data. By utilizing repetitive mild TBI (rmTBI) mouse models, our aim was to examine the pathological changes of CTE-associated structures, specifically the ATs. Results: Our rmTBI mouse models showed symptoms of depressive behavior and memory deficit, alongside an increased p-Tau expression in their neurons and astrocytes in both the hippocampus and cortex. rmTBI induced oxidative stress in endothelial cells and nitric oxide (NO) generation in astrocytes, which were mediated by hypoxia and increased hypoxia-inducible factor 1-α (HIF1α). There was also correlated decreased regional cerebral tissue perfusion units, mild activation of astrocytes and NFκB phosphorylation, increased expression of inducible nitric oxide synthase (iNOS), increased endothelial nitric oxide synthase (eNOS) uncoupling with decreased tetrahydrobiopterin, and increased expression of nitrotyrosine, NADPH oxidase 2 (Nox2)/nuclear factor (erythroid-derived 2) factor 2 (Nrf2) signaling proteins. Combined, these effects induced peroxynitrite formation and hyperphosphorylation of tau in the hippocampus and cortex toward the formation of ATs. Innovation: Our model features molecular pathogenesis events of CTE with clinically relevant latency periods. In particular, this is the first demonstration of an increased astrocytic iNOS expression in an in vivo model. Conclusion: We propose a novel mechanism of uncoupled eNOS and NO contribution to Tau phosphorylation and AT formation in rmTBI brain, toward an increased molecular understanding of the pathophysiology of human CTE.