Falk, Gary W.

Abstract Barrett's esophagus (BE), a complication of gastroesophageal reflux disease (GERD), predisposes patients to esophageal adenocarcinoma (EAC). Reliable biomarkers for early detection and discovery of potential drug targets are urgently needed for improved BE and EAC patient outcomes. In this study, COX2 and TBXAS are highly expressed in BE and EAC patients accompanied by a pronounced elevation of circulating TXA2 levels in patient biopsy samples. Acetylsalicylic acid (ASA) suppressed BE and EAC growth by targeting the TXA2 pathway in a esophagoduodenostomy mouse model of reflux. Additionally, biopsies from patients showed that ASA substantially decreased serum TXA2 levels, resulting in reduced inflammation in a window opportunity clinical trial. Overall, this study establishes the importance of the COX1/2-driven TXA2 pathway in BE and EAC pathophysiology and lays the groundwork for introducing a TXA2-targeting strategy for EAC prevention and early detection. ASA targets the TXA2 pathway and suppresses BE and EAC. Citation Format: Tianshun Zhang, Qiushi Wang, Wei-Ya Ma, Keke Wang, Xiaoyu Chang, Michele L. Johnson, Ruihua Bai, Ann M. Bode, Nathan R. Foster, Gary W. Falk, Prasad G. Iyer, Zigang Dong. Inhibition of COX1/2-driven thromboxane A2 pathway suppresses Barrett's esophagus and esophageal adenocarcinoma development [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2593.

ABSTRACT Objectives: Clinical features of eosinophilic esophagitis (EoE) have been well‐described in the literature, however, characterization of features experienced by patients with other eosinophilic gastrointestinal diseases (EGIDs) is lacking. Using data collected from a patient contact registry, we sought to characterize and contrast patient‐reported gastrointestinal and extragastrointestinal symptoms and comorbidities in non‐EoE EGIDs, including eosinophilic gastritis, gastroenteritis and colitis, relative to EoE. Methods: We conducted a cross‐sectional study of contact registry data collected from 2015 to 2018. Statistical comparisons were made using chi‐square (categorical measures) and the Mann‐Whitney U test (continuous measures). Multivariable analyses were used to evaluate associations between treatment and feelings of isolation. Results: Of the 715 reporting an EGID diagnosis (n = 525 EoE; n = 190 non‐EoE EGID), a higher proportion of those with a non‐EoE EGID reported more frequent specific and nonspecific gastrointestinal symptoms, including nausea, abdominal pain, diarrhea, constipation, and bloating ( P < 0.01 for all). Participants with a non‐EoE EGID were more likely to report higher frequency of fatigue, isolation, and deep muscle or joint pain ( P < 0.01 for all). Specific food elimination and elemental formula treatments were associated with increased odds of more frequent (at least weekly) feelings of isolation for participants with EoE (adjusted odds rtaio [aOR]: 2.4; 95% confidence interval [CI]: 1.5‐‐4.1 for specific food elimination and adjusted OR: 1.9; 95% CI: 1.2‐‐3.3 for elemental formula). Conclusions: Significant differences exist in the symptoms and comorbidities experienced between those with EoE versus non‐EoE EGIDs. Additional investigation is needed to elucidate the factors that may contribute to the high disease burden of these poorly understood conditions.

INTRODUCTION: Eosinophilic gastrointestinal diseases (EGIDs) are a set of inflammatory diseases subclassified according to the site(s) of abnormal accumulation of eosinophils (eos) in the gastrointestinal (GI) tract such as eosinophilic esophagitis (EoE), gastroenteritis (EGE), and colitis. These conditions often decrease quality of life due to debilitating symptoms. While the pathogenesis of EGIDs is primarily thought to be driven by eos, there is increasing evidence for the involvement of mast cells (MCs). AIM: To characterize symptomatic patients (pts) with suspected EG/EGE who did not meet histopathologic entry criteria for mucosal eosinophilia for a Phase 2 randomized, double-blind, placebo-controlled study of AK002, an anti-Siglec-8 antibody. METHODS: To undergo screening endoscopy for this study, pts were required to report an average symptom score ≥3 (0 to 10 scale) for abdominal pain, nausea, and/or diarrhea on a daily patient-reported outcome questionnaire for ≥2 weeks and have no other known cause for GI symptoms. During the screening endoscopy, biopsies were systematically obtained from the stomach and duodenum, and read by a single pathologist. Eos counts (eos/hpf; hpf area = 0.237 mm 2 ) were assessed on H&E slides. To quantify MCs, immunohistochemistry for tryptase was performed. We quantified eos and MCs in the stomach and duodenum. Histopathologic entry criteria for the randomized study was ≥30 eos/hpf in 5 hpfs in the stomach (EG) and/or ≥30 eos/hpf in 3 hpfs in the duodenum (EGE). A literature review was conducted to determine normal MC counts in the GI tract. RESULTS: Eighty-eight pts underwent screening endoscopy based upon suspected EG/EGE and active symptoms, and 72 pts met histopathologic eos criteria. All pts whose eos did not meet entry criteria (n = 16) were found to have elevated MC counts (Figure 1; reported normal range = 12-19 MCs/hpf). In these pts, the mean gastric eos count was 6 eos/hpf in 5 hpfs and mean duodenal eos count was 15 eos/hpf in 3 hpfs. In contrast, these pts exhibited a mean gastric MC count of 47 MC/hpf in 5 hpfs and a mean duodenal MC count of 49 MC/hpf in 3 hpfs. Almost all symptomatic pts screened (87/88; 99%) had elevated MC counts. CONCLUSION: Data from this large randomized EG/EGE study showed that symptomatic pts with suspected EG/EGE had increased mucosal MCs with or without mucosal eosinophilia. These data suggest that MCs may play a role in pts with suspected EG/EGE and raise the possibility of a unique clinical presentation driven by MCs.

INTRODUCTION: Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease for which there is an unmet clinical need for new therapies. The safety and efficacy of budesonide oral suspension (BOS) for the treatment of EoE has been demonstrated in a previous phase 2 study. The current phase 3 study evaluated the efficacy and safety of BOS in a large cohort of patients with EoE. METHODS: This randomized, double-blind, placebo-controlled trial (SHP621-301; NCT02605837) investigated the safety and efficacy of BOS in patients (11–55 years) with EoE and dysphagia. Patients were randomized 2:1 to 2.0 mg BOS or placebo twice daily (b.i.d.) for 12 weeks (Figure 1). Co-primary endpoints were histologic (peak eosinophil count ≤6 eosinophils/high-powered field [eos/hpf]) and dysphagia symptom (≥30% decrease in symptoms as measured by the Dysphagia Symptom Questionnaire [DSQ]) responses after 12 weeks of therapy. Secondary endpoints included change in DSQ score and change in EoE Endoscopic Reference Score (EREFS) from baseline to final treatment period. Safety was also assessed. RESULTS: A total of 322 patients were randomized (BOS, n = 215; placebo, n = 107), of whom 318 patients received at least one dose of double-blind therapy (BOS, n = 213; placebo, n = 105) (Table 1). The primary outcomes were achieved, with significantly more histologic and symptom responders in the BOS-treated than the placebo-treated group (53.1% vs 1.0%, P < 0.001; 52.6% vs 39.1%, P = 0.024, respectively; Figure 2). Improvements in mean DSQ score from baseline to week 12 were significantly greater in the BOS group (n = 197) than the placebo group (n = 89) (−13.0 vs −9.1; P = 0.015). Similarly, improvements in mean EREFS scores were significantly greater with BOS (n = 202) than placebo (n = 93) (−4.0 vs −2.2; P < 0.001). In total, 61.0% of patients reported a treatment-emergent adverse event (TEAE) (BOS, 61.0%; placebo, 61.0%). Only 2.5% of patients experienced a TEAE leading to dose discontinuation (BOS, 1.4%; placebo, 4.8%). Few patients had severe or serious TEAEs on BOS or placebo. No life-threatening TEAEs were reported. CONCLUSION: This phase 3 trial demonstrated the efficacy of BOS as induction therapy for EoE. BOS resulted in significant improvements in histologic, symptomatic and endoscopic endpoints compared with placebo. The majority of TEAEs were mild to moderate and comparable between placebo and BOS. A double-blind, placebo-controlled maintenance study (SHP621-302) is ongoing.

AbstractBackgroundFamilial aggregation and segregation analysis studies have provided evidence of a genetic basis for esophageal adenocarcinoma (EAC) and its premalignant precursor, Barrett's esophagus (BE). We aim to demonstrate the utility of linkage analysis to identify the genomic regions that might contain the genetic variants that predispose individuals to this complex trait (BE and EAC).MethodsWe genotyped 144 individuals in 42 multiplex pedigrees chosen from 1000 singly ascertained BE/EAC pedigrees, and performed both model‐based and model‐free linkage analyses, using S.A.G.E. and other software. Segregation models were fitted, from the data on both the 42 pedigrees and the 1000 pedigrees, to determine parameters for performing model‐based linkage analysis. Model‐based and model‐free linkage analyses were conducted in two sets of pedigrees: the 42 pedigrees and a subset of 18 pedigrees with female affected members that are expected to be more genetically homogeneous. Genome‐wide associations were also tested in these families.ResultsLinkage analyses on the 42 pedigrees identified several regions consistently suggestive of linkage by different linkage analysis methods on chromosomes 2q31, 12q23, and 4p14. A linkage on 15q26 is the only consistent linkage region identified in the 18 female‐affected pedigrees, in which the linkage signal is higher than in the 42 pedigrees. Other tentative linkage signals are also reported.ConclusionOur linkage study of BE/EAC pedigrees identified linkage regions on chromosomes 2, 4, 12, and 15, with some reported associations located within our linkage peaks. Our linkage results can help prioritize association tests to delineate the genetic determinants underlying susceptibility to BE and EAC.

Abstract Background: Barrett's esophagus is often asymptomatic and only a small portion of Barrett's esophagus patients are currently diagnosed and under surveillance. Therefore, it is important to develop risk prediction models to identify high-risk individuals with Barrett's esophagus. Familial aggregation of Barrett's esophagus and esophageal adenocarcinoma, and the increased risk of esophageal adenocarcinoma for individuals with a family history, raise the necessity of including genetic factors in the prediction model. Methods to determine risk prediction models using both risk covariates and ascertained family data are not well developed. Methods: We developed a Barrett's Esophagus Translational Research Network (BETRNet) risk prediction model from 787 singly ascertained Barrett's esophagus pedigrees and 92 multiplex Barrett's esophagus pedigrees, fitting a multivariate logistic model that incorporates family history and clinical risk factors. The eight risk factors, age, sex, education level, parental status, smoking, heartburn frequency, regurgitation frequency, and use of acid suppressant, were included in the model. The prediction accuracy was evaluated on the training dataset and an independent validation dataset of 643 multiplex Barrett's esophagus pedigrees. Results: Our results indicate family information helps to predict Barrett's esophagus risk, and predicting in families improves both prediction calibration and discrimination accuracy. Conclusions: Our model can predict Barrett's esophagus risk for anyone with family members known to have, or not have, had Barrett's esophagus. It can predict risk for unrelated individuals without knowing any relatives' information. Impact: Our prediction model will shed light on effectively identifying high-risk individuals for Barrett's esophagus screening and surveillance, consequently allowing intervention at an early stage, and reducing mortality from esophageal adenocarcinoma. Cancer Epidemiol Biomarkers Prev; 25(5); 727–35. ©2016 AACR.

Abstract Background: In patients with Barrett's esophagus, chronic reflux injury and inflammation are associated with esophageal adenocarcinoma, one of the most rapidly increasing lethal cancers. Epidemiological and preclinical studies support decreased risk of esophageal adenocarcinoma with NSAID use. Gastroesophageal refluxate contents can promote carcinogenesis in Barrett's metaplasia by activating AKT, which up regulates COX-2 expression and prostaglandin biosynthesis. We recently noted that neoplastic transformation in Barrett's esophagus is associated with increased AKT expression, particularly isoform AKT1. The AIM of this study is to investigate the effect of NSAID (Aspirin) use in patients with Barrett's esophagus on AKT1 expression using frozen tissue from the randomized, phase II trial of aspirin and esomeprazole for esophageal cancer chemoprevention in Barrett's esophagus patients and to assess the functional consequences of AKT1 expression in-vitro. Methods and Results: In a subset of patients (12 of 120 patients) with Barrett's esophagus who were randomized to placebo, lower dose (81 mg) or higher dose (325 mg) Aspirin for 4 weeks, both PCR and Western blot revealed marked reduction in AKT1 expression in patients who received 325 mg of Aspirin daily compared to patients who received placebo. Our in-vitro experiments support that AKT1 expression is functionally relevant to the process of carcinogenesis in Barrett's epithelial cells. Using adenovirus to induce AKT1 expression, we show that increased AKT1 expression increases Barrett's epithelial cell growth, facilitates RAS-mediated transformation of pre-neoplastic epithelial cells and promotes colony formation. Since AKT1 is known as Warburg kinase and regulates cellular glucose uptake to support aerobic glycolysis during growth de-regulation and neoplasia, we examined the uptake of fluorescent deoxyglucose analog (2-NBDG) in Barrett's epithelial cells transduced with AKT1 adenovirus. At 48 hrs, compared to control, AKT1 overexpression resulted in increased glucose uptake both by metaplastic and neoplastic Barrett's epithelial cells. Transcriptional repression of AKT1 abrogated the 2-NBDG uptake by these cells. Finally, we did pathway specific qPCRs and noted that use of Aspirin is associated with altered expression of chromatin remodelers that could down-regulate AKT1 expression. Conclusion: Collectively, our results demonstrate that Aspirin mediated down-regulation of Warburg kinase AKT1 in patients with Barrett?s esophagus is a novel mechanism for the regulation of Barrett?s epithelial cell growth. The in-depth characterization of molecular mechanisms is currently underway. This abstract is also presented as Poster A82. Citation Format: Navtej S. Buttar, Gary W. Falk, Cathrine J. DeMars, Sonia Chowdhury, Ahmed Elebiary, Anamay Sharma, Sidhartha Chaudhry, Nathan R. Foster, Katie L. Allen Ziegler, Yvonne Romero, Norman E. Marcon, Thomas Schnell, Douglas A. Corley, Prateek Sharma, Marcia R. Cruz-Correa, Chin Hur, David E. Fleischer, Amitabh Chak, Kenneth R. DeVault, David S. Weinberg, Gary Della’Zanna, Ellen Richmond, Thomas C. Smyrk, Sumithra Mandrekar, Paul J. Limburg. Aspirin mediated downregulation of Warburg kinase AKT1 in patients with Barrett's esophagus: Implications in neoplastic transformation. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr PR-03.

Abstract Background and Aims: In patients with Barrett's esophagus (BE), reflux-induced injury promotes esophageal adenocarcinoma, presumably through cyclooxygenase 2 (COX-2) related pathways. Proton pump inhibitors (PPIs) and nonsteroidal anti-inflammatory drugs (NSAIDs) may interrupt reflux-associated carcinogenesis by reducing acid exposure and subsequent inflammation. However, clinical trial data regarding the chemopreventive efficacy of a PPI + NSAID combination are limited. The aim of this multi-center, randomized, phase II trial was to assess the effects of a 28-day intervention with esomeprazole 40 mg bid and aspirin 81 mg qd, 325 mg qd, or placebo qd on tissue prostaglandin E2 (PGE2) concentrations in BE patients. Methods: Using the infrastructure of the Cancer Prevention Network, participants (&gt; 18 years) with histologically confirmed non dysplastic BE were randomly assigned to receive one of three interventions for 28 days: (arm A) esomeprazole 40 mg bid+ aspirin 81 mg placebo qd + aspirin 325 mg placebo qd (n=42); (arm B) esomeprazole 40 mg bid+ aspirin 81 mg qd + aspirin placebo 325 qd (n=63); (arm C) esomeprazole 40 mg bid + aspirin 81 mg qd placebo + aspirin 325 mg qd (n=63). Esophageal biopsies were obtained pre- and post-intervention to assess change in PGE2 concentration as the primary endpoint. Results: In total, 122 participants were randomized, 121 (99%) completed the trial per protocol, and 115 (94%) were evaluated for the primary endpoint. Baseline characteristics were similar across intervention arms. The absolute change (mean + SD) in tissue PGE2 concentration was −67.6 (229.68) in Arm A, −120.9 (281.28) in Arm B (p = 0.10 vs Arm A) and −174.9 (263.62) in Arm C (p = 0.02 vs Arm A). Conclusions: In combination with esomeprazole 40 mg twice per day, aspirin 325 mg per day significantly reduced tissue PGE2 concentration in BE patients after a 28-day intervention, as compared to aspirin placebo. Given the relevance of PGE2 pathways in BE-associated carcinogenesis, further evaluation of this chemoprevention strategy in larger, more definitive phase III trials is warranted. Citation Information: Cancer Prev Res 2011;4(10 Suppl):CN06-03.