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Emerging evidence indicates the potential clinical significance of specific microbial signatures as diagnostic and prognostic biomarkers, in multiple cancers. However, to date, no studies have systematically interrogated circulating metagenome profiling in oesophageal adenocarcinoma (EAC) patients, particularly as novel non-invasive, early detection, surveillance and prognostic classifiers.Metagenome sequencing was performed on 81 serum specimens collected across EAC spectrum, with sequencing reads classified using Bracken and MetaPhlAn3. Followed by the Linear Discriminant Analysis effect size (LEfSe) method to identify microbial profiles between groups. Logistic regression and Kaplan-Meier analyses were used to build classifiers.A significant loss of alpha and beta diversity was identified in serum specimens from EAC patients. We observed a shift in microbial taxa between each group-at the phylum, genus, and species level-with Lactobacillus sakei as the most prominent species in gastroesophageal reflux (GERD) vs other patient groups. Interestingly, LEfSe analysis identified a complete loss of Lactobacillus (L. Sakei and L. Curvatus), Collinsella stercoris and Bacteroides stercoris but conversely a significant increase in Escherichia coli in patients with EAC. Finally, we developed a metagenome panel that discriminated EAC from GERD patients with an AUC value of 0.89 (95% CI: 0.78-0.95; P 0.001) and this panel in conjunction with the TNM stage was a robust predictor of overall survival (≥24 months; AUC = 0.84 (95% CI: 0.66-0.92; P = 0.006)).This study firstly describes unique blood-based microbial profiles in patients across EAC carcinogenesis, that are further utilised to establish a novel circulating diagnostic and prognostic metagenomic signature for EAC.Accumulating data indicates the clinical relevance of specific microbial signatures as diagnostic and prognostic biomarkers, in multiple cancers. However, to date, no studies have systematically interrogated circulating metagenome profiling in patients with oesophageal adenocarcinoma (EAC). Herein, we performed metagenome sequencing in serum specimens from EAC patients 81 collected across EAC spectrum and observed a significant loss of alpha and beta diversity, with a shift in microbial taxa between each group-at the phylum, genus, and species level-with Lactobacillus sakei as the most prominent species in gastroesophageal reflux (GERD) vs other patient groups. Interestingly, LEfSe analysis identified a complete loss of Lactobacillus (L. Sakei and L. Curvatus), Collinsella stercoris and Bacteroides stercoris but conversely a significant increase in Escherichia coli in patients with EAC. Finally, we developed a metagenome panel that discriminated EAC from GERD patients with an AUC value of 0.89 and this panel, in conjunction with the TNM stage, was a robust predictor of overall survival. This study for the first time describes unique blood-based microbial profiles in patients across EAC carcinogenesis, that are further utilised to establish a novel circulating diagnostic and prognostic metagenomic signature for EAC.

Esophageal adenocarcinoma (EAC) is a leading cause of cancer deaths. Pexidartinib, a multi-gene tyrosine kinase inhibitor, through targeting colony-stimulating factor 1 (CSF-1) receptor (CSF-1R), down modulates macrophage-mediated pro-survival tumor signaling. Previously, CSF-1R inhibitors have successfully shown to enhance antitumor activity of PD-1/PD-L1 inhibitors by suppressing tumor immune evasion, in solid tumors. In this study, we investigated the antitumor activity of pexidartinib alone or in combination with blockade of PD-1 in a de novo EAC rat model. Here, we showed limited toxicity with significant tumor shrinkage in pexidartinib treated animals compared to controls, single agent and in combination with a PD-1 inhibitor, AUNP-12. Suppression of CSF-1/CSF-1R axis resulted in enhanced infiltration of CD3 + CD8 + T cells with reduced M2 macrophage polarization, in the tumor microenvironment (TME). Endpoint tissue gene expression in pexidartinib treated animals demonstrated upregulation of BAX, Cas3, TNFα, IFNγ and IL6 and downregulation of Ki67, IL13, IL10, TGFβ and Arg1 (P

Purpose: To determine the safety and tolerability of olaparib with cisplatin and gemcitabine, establish the maximum tolerated dose (MTD), and evaluate the pharmacodynamic and pharmacokinetic profile of the combination.Experimental Design: We conducted a phase I study of olaparib with cisplatin and gemcitabine in patients with advanced solid tumors. Treatment at dose level 1 (DL1) consisted of olaparib 100 mg orally every 12 hours on days 1 to 4, gemcitabine 500 mg/m2 on days 3 and 10, and cisplatin 60 mg/m2 on day 3. PAR levels were measured in peripheral blood mononuclear cells (PBMC).Results: Dose-limiting toxicities (DLT) in two of three patients at DL1 included thrombocytopenia and febrile neutropenia. The protocol was amended to enroll patients treated with ≤2 prior severely myelosuppressive chemotherapy regimens and treated with olaparib 100 mg once daily on days 1 to 4 (DL−1). No DLTs were seen in six patients at DL−1. Because of persistent thrombocytopenia and neutropenia following a return to DL1, patients received 100 mg olaparib every 12 hours on day 1 only. No hematologic DLTs were observed; nonhematologic DLTs included gastrointestinal bleed, syncope, and hypoxia. Of 21 patients evaluable for response, two had partial response. Olaparib inhibited PARP in PBMCs and tumor tissue, although PAR levels were less effectively inhibited when olaparib was used for a short duration.Conclusions: Olaparib in combination with cisplatin and gemcitabine is associated with myelosuppression even at relatively low doses. Modified schedules of olaparib in chemotherapy naive patients will have to be explored with standard doses of chemotherapy. Clin Cancer Res; 18(8); 2344–51. ©2012 AACR.

Purpose: P-glycoprotein (Pgp) antagonists have been difficult to develop because of complex pharmacokinetic interactions and a failure to show meaningful results. Here we report the results of a pharmacokinetic and pharmacodynamic trial using a third-generation, potent, noncompetitive inhibitor of Pgp, tariquidar (XR9576), in combination with docetaxel.Experimental Design: In the first treatment cycle, the pharmacokinetics of docetaxel (40 mg/m2) were evaluated after day 1 and day 8 doses, which were administered with or without tariquidar (150 mg). 99mTc-sestamibi scanning and CD56+ mononuclear cell rhodamine efflux assays were conducted to assess Pgp inhibition. In subsequent cycles, 75 mg/m2 docetaxel was administered with 150 mg tariquidar every 3 weeks.Results: Forty-eight patients were enrolled onto the trial. Nonhematologic grade 3/4 toxicities in 235 cycles were minimal. Tariquidar inhibited Pgp-mediated rhodamine efflux from CD56+ cells and reduced 99mTc-sestamibi clearance from the liver. There was striking variability in basal sestamibi uptake; a 12% to 24% increase in visible lesions was noted in 8 of 10 patients with lung cancer. No significant difference in docetaxel disposition was observed in pairwise comparison with and without tariquidar. Four partial responses (PR) were seen (4/48); 3 in the non–small cell lung cancer (NSCLC) cohort, measuring 40%, 57%, and 67% by RECIST, and 1 PR in a patient with ovarian cancer.Conclusions: Tariquidar is well tolerated, with less observed systemic pharmacokinetic interaction than previous Pgp antagonists. Variable effects of tariquidar on retention of sestamibi in imageable lung cancers suggest that follow-up studies assessing tumor drug uptake in this patient population would be worthwhile. Clin Cancer Res; 17(3); 569–80. ©2010 AACR.

Purpose: Acquired EGFR T790M mutations are the most frequently identified resistance mechanism to EGFR tyrosine kinase inhibitors (TKI) in patients with EGFR-mutant lung cancers. ASP8273 is a third-generation EGFR TKI with antitumor activity in preclinical models of EGFR-mutant lung cancer that targets mutant EGFR, including EGFR T790M.Experimental Design: In this multicohort, phase I study (NCT02113813), escalating doses of ASP8273 (25–500 mg) were administered once daily to non–small cell lung cancer (NSCLC) patients with disease progression after prior treatment with an EGFR TKI. EGFR T790M was required for all cohorts, except the dose escalation cohort. Primary endpoints were safety/tolerability; secondary endpoints were determination of the RP2D, pharmacokinetic profile, and preliminary antitumor activity of ASP8273. Evaluation of the use of EGFR mutations in circulating free DNA (cfDNA) as a biomarker of ASP8273 treatment effects was an exploratory endpoint.Results: A total of 110 patients were treated with ASP8273 across dose escalation (n = 36), response–expansion (n = 36), RP2D (300 mg; n = 19) and food–effect (n = 19) cohorts. The most common treatment-emergent adverse events included diarrhea, nausea, fatigue, constipation, vomiting, and hyponatremia. Across all doses, in patients with EGFR T790M, the response rate was 30.7% (n = 27/88; 95% CI, 19.5%–44.5%), and median progression-free survival was 6.8 months (95% CI, 5.5–10.1 months). EGFR mutations in cfDNA, both the activating mutation and EGFR T790M, became undetectable in most patients in the setting of clinical response and reemerged upon disease progression.Conclusions: ASP8273 was well tolerated and promoted antitumor activity in patients with EGFR-mutant lung cancer with disease progression on prior EGFR TKI therapy. Clin Cancer Res; 23(24); 7467–73. ©2017 AACR.

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Supplementary Table 1. Pharmacokinetic Parameters of ASP8273 from Patients in Dose-Escalation Cohort (PKAS) ; Supplementary Figure 1. Study design; Supplementary Figure 2. Quantitative change in EGFR cfDNA from baseline to Cycle 2 in escalating dose levels of ASP8273; Supplementary Figure 3. Changes in Levels of Mutant EGFR cfDNA (Activating or T790M) in Patients after One Cycle of Treatment with ASP8273 by Best Overall Response; Supplementary Figure 4. Identification of EGFR activating mutations, EGFR T790M and EGFR C797S in cfDNA from patients with Emergence of acquired resistance to ASP8273.

Supplementary Figures S1-S2; Supplementary Tables S1-S3.

Purpose: Sorafenib, a multikinase inhibitor targeting Raf and VEGFR, has shown activity in unselected patients with non–small-cell lung cancer (NSCLC). At present there are no validated biomarkers indicative of sorafenib activity.Experimental Design: Patients received sorafenib 400 mg BID daily to determine activity and tolerability and to measure its biological effects. KRAS mutation status (N = 34), angiogenesis markers (VEGF, bFGF, FLT-1, PLGF-1) and imaging with DCE-MRI (dynamic contrast enhanced MRI) to determine early changes in tumor vascular characteristics were evaluated. Three parameters Ktrans, Kep, and Ve were measured by DCE-MRI at baseline and day 14 of cycle 1. Cytokine analysis was done on days 0, 14, 28, and 54.Results: Thirty-seven patients with previously treated stage IV NSCLC were enrolled in this single-center phase II trial. In 34 evaluable patients, 2 had partial responses and 20 had stable disease for 3 to 17 months, a disease control rate of 65%. The median progression-free survival (PFS) was 3.4 months, and median overall survival (OS) was 11.6 months. Toxicity was consistent with the known side effects of sorafenib. KRAS (32%) and EGFR mutations (22%) showed no correlation with response, PFS, or OS. Kep, was significant in predicting an improvement in OS (P = 0.035) and PFS (P = 0.029). Cytokine analysis demonstrated an improved OS for bFGF day 0 (6 pg/mL; P = 0.042), whereas a PFS benefit was seen with bFGF at day 28 (6; P = 0.028).Conclusions: KRAS and EGFR mutational status showed no correlation with response, PFS, or OS. Radiologic and cytokine changes may act as biomarkers indicative of early angiogenesis inhibition. Clin Cancer Res; 17(5); 1190–9. ©2011 AACR.

Purpose: To determine the maximum tolerated dose (MTD), toxicities, and pharmacokinetic/pharmacodynamic profile of the Hsp90 inhibitor PF-04929113 (SNX-5422) in patients with advanced solid tumors and lymphomas.Methods: This was a single-institution, phase I, dose-escalation study of PF-04929113 administered twice weekly. Endpoints included determination of dose-limiting toxicities (DLT), MTD, the safety profile of PF-04929113, pharmacodynamic assessment of PF-04929113 on Hsp70 induction, pharmacokinetic analysis of PF-04928473 (SNX-2112) and its prodrug PF-04929113, and assessment of response.Results: Thirty-three patients with advanced malignancies were treated. Dose escalation was continued up to 177 mg/m2 administered orally twice a week. One DLT (nonseptic arthritis) was noted. No grade 4 drug-related adverse events were seen; grade 3 adverse events included diarrhea (9%), nonseptic arthritis (3%), aspartate aminotransferase elevation (3%), and thrombocytopenia (3%). No objective responses were seen in 32 evaluable patients. Fifteen patients (47%) had stable disease; 17 patients (53%) had progressive disease. Pharmacokinetic data revealed rapid absorption, hepatic, and extrahepatic clearance, extensive tissue binding, and almost linear pharmacokinetics of the active drug PF-04928473. Pharmacodynamic studies confirmed inhibition of Hsp90 and a linear correlation between pharmacokinetic parameters and Hsp70 induction.Conclusions: PF-04929113 administered orally twice a week is well tolerated and inhibits its intended target Hsp90. No objective responses were seen, but long-lasting stabilizations were obtained. Although no clinically significant drug-related ocular toxicity was seen in this study, the development of PF-04929113 has been discontinued because of ocular toxicity seen in animal models and in a separate phase I study. Clin Cancer Res; 17(21); 6831–9. ©2011 AACR.

Supplementary Figures S1-S2; Supplementary Tables S1-S2.

A detailed understanding of the molecular and immunological changes that occur longitudinally across tumors exposed to immune checkpoint inhibitors is a significant knowledge gap in oncology. To address this unmet need, we created a statewide biospecimen collection and clinical informatics system to enable longitudinal tumor and immune profiling and to enhance translational research. The Texas Immuno-Oncology Biorepository (TIOB) consents patients to collect, process, store, and analyze serial biospecimens of tissue, blood, urine, and stool from a diverse population of over 100,000 cancer patients treated each year across the Baylor Scott & White Health system. Here we sought to demonstrate that these samples were fit for purpose with regard to downstream multi-omic assays. Plasma, urine, peripheral blood mononuclear cells, and stool samples from 11 enrolled patients were collected from various cancer types. RNA isolated from extracellular vesicles derived from plasma and urine was sufficient for transcriptomics. Peripheral blood mononuclear cells demonstrated excellent yield and viability. Ten of 11 stool samples produced RNA quality to enable microbiome characterization. Sample acquisition and processing methods are known to impact sample quality and performance. We demonstrate that consistent acquisition methodology, sample preparation, and sample storage employed by the TIOB can produce high-quality specimens, suited for employment in a wide array of multi-omic platforms, enabling comprehensive immune and molecular profiling.

Introduction: Preclinical studies suggest cooperativity between blocking the human epidermal growth factor receptor 2 (HER2) and the vascular endothelial growth factor (VEGF) pathways in gastroesophageal adenocarcinomas (GEAs). Methods:Patients with previously untreated advanced HER2 positive GEAs were treated with standard of care chemotherapy capecitabine 1,200 mg/m2 days 1-14 and oxaliplatin 130 mg/m2 day 1 (CAPOX) plus trastuzumab 6 mg/kg day 1, once every 3 weeks. Investigational agent bevacizumab (7.5 mg/kg, VEGF mAb) was added on day 1 of each cycle for all patients. The primary endpoint was radiographic objective response rate by RECIST 1.1. ctDNA was extracted and profiled from serially banked plasma samples (every other treatment cycle) using CLIA certified 152-gene next generation sequencing (NGS) panel assay, PredicineCARETM. Results:Sixty one patients were screened for the study of whom 24 were ineligible. Thirty-seven patients were enrolled, and one withdrew consent prior to starting. Thirty-six patients were evaluable for efficacy and safety. The median follow-up was 23.2 months (IQR: 11.0 - 46.9 months). All enrolled patients are now off study. Radiographic objective response rate was 81%. Median progression-free survival (PFS) and overall survival (OS) were 14.0 months (95% CI, 11.3 -36.4) and 23.2 months (95% CI, 16.6-36.4), respectively. The most common grade 3-4 toxicities were diarrhea, peripheral neuropathy, and hypertension. Baseline ctDNA profiling identified HER2 amplifications in 76.7% of tested cases (23/30). Baseline ctDNA based tumor fraction (TF) was highly prognostic and TF > 50th centile had a statistically significantly worse PFS of 11.3 months (95% CI 5.2-18) vs. 22.7 months (95% CI 18.1-NA), p value = 0.0013, and OS of 15.4 months (95% CI 8.0-27.6) vs. 28.0 months (95% CI 17.8-NA), p value = 0.022. 56.7% of cases (17/30) had alternative MAPK drivers present in pretreatment ctDNA, most commonly amplifications in EGFR, FGFR1, MET, and KRAS. Additional MAPK alterations were associated with worse PFS of 12.5 months (95% CI 5.2-NA) vs. 22.7 months (95% CI 8.5-NA), p-value = 0.0067, and OS of 16.5 months (95% CI 8.0-27.6) vs. 32.3 months (95% CI 17.8-NA), p-value = 0.015. 19 cases had plasma profiled at time of clinical resistance of whom 10 showed new oncogenic mutations not detectable in the matched baseline sample. These included mutations in MAPK pathway (KRAS, NRAS, BRAF, HER2; n = 1 each) and PI3K pathway (PTEN, PIK3CA; n = 1 each), suggesting a role in therapeutic resistance. Conclusions:The combination of CAPOX, trastuzumab and bevacizumab shows striking clinical activity comparable to novel triplet regimens that include PD1 blockade for HER2+ GEAs. Further evaluation of VEGF mAb in combination with chemoimmunotherapy and anti-PD1 regimens is warranted. Diagnostic ctDNA profiling identifies cases with high TF and alternative MAPK drivers who have worse outcomes. Serial measurement of ctDNA may allow early identification of novel genetic resistance mechanisms which can aid attempts at early intervention. Citation Format: Harshabad Singh, Kristen E. Lowder, Kevin Kapner, Ronan J. Kelly, Hui Zheng, Nadine J. McCleary, Thomas A. Abrams, Jennifer A. Chan, Eileen M. Regan, Samuel J. Klempner, Alison M. Hannigan, Lauren K. Brais, Elizabeth A. Andrews, Matthew B. Yurgelun, James M. Cleary, Douglas A. Rubinson, Lauren L. Ritterhouse, Garrett E. Maron, Andrew J. Aguirre, Lu Tan, Pan Du, Jeffrey A. Meyerhardt, Emma Gardecki, Jochen K. Lennerz, Shidong Jia, Brian M. Wolpin, Peter C. Enzinger. Long term results and ctDNA correlatives for CAPOX BETR: A multi-center phase II trial of capecitabine, oxaliplatin, bevacizumab and trastuzumab for previously untreated HER2 positive metastatic gastroesophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT155.

Introduction: There is a critical need to incorporate molecular assessments of minimal residual disease (MRD) during neoadjuvant immunotherapy, in order to identify individuals at high risk for disease recurrence based on analyses of circulating cell-free tumor DNA (ctDNA) landscapes. Here we employed longitudinal liquid biopsies to dynamically assess clinical outcomes with neoadjuvant immuno-chemoradiotherapy in patients with esophageal/gastroesophageal junction (E/GEJ) cancer. Methods: We utilized targeted error-correction sequencing to perform high-depth ctDNA next-generation sequencing for 141 serial plasma and 32 matched white blood cell (WBC) DNA samples from 32 patients with operable stage II/III E/GEJ cancer that received neoadjuvant immune checkpoint blockade (ICB) with chemoradiotherapy prior to surgery (NCT03044613). ctDNA analyses were performed at baseline, post-ICB induction, after completion of chemoradiotherapy (pre-op), and post-operatively (post-op). Using a tumor-agnostic WBC DNA-informed panel NGS approach we determined the cellular origin of plasma variants, filtering out germline and clonal hematopoiesis (CH) variants and evaluated ctDNA clonal dynamics over time. Molecular MRD was evaluated post-ICB, pre-op and post-op and correlated with recurrence-free (RFS) and overall survival (OS). Results: Twenty out of 32 patients had detectable ctDNA at any timepoint. Of the 12 patients with undetectable ctDNA, 9 had only CH- and/or germline-derived variants, while 3 patients had no detectable variants of any origin. ctDNA clearance post-ICB was correlated with tumor regression >80% at the time of resection (Fischer’s exact p=0.04). The subset of patients that did not attain complete pathologic response was heterogeneous with respect to ctDNA dynamics; such that ctDNA clearance pre-op identified patients with longer OS despite residual tumor of >0% at the time of resection (log rank p=0.06). Patients with undetectable ctDNA or ctDNA clearance pre-op had a longer RFS (log rank p=0.007) and OS (log rank p=0.03). Molecular MRD was associated with RFS and OS such that patients with ctDNA clearance post-op had longer RFS (log-rank p=0.007) and OS (log-rank p=0.017). Conclusion: ctDNA clearance post-ICB, pre-op and post-op reflects differential clinical outcomes for patients with E/GEJ cancer receiving neoadjuvant immuno-chemoradiotherapy. Understanding ctDNA dynamics and their relationship with pathological response and long-term outcomes can help identify patients at higher risk for recurrence and open a therapeutic window for future intervention. Citation Format: Blair V. Landon, Ronan J. Kelly, Ali H. Zaidi, Archana Balan, Jenna V. Canzoniero, Gavin Pereira, Zineb Belcaid, Russell K. Hales, K Ranh Voong, Richard J. Battafarano, Blair A. Jobe, Stephen C. Yang, Stephen Broderick, Jinny Ha, Kellie N. Smith, Elizabeth Thompson, Fyza Y. Shaikh, James R. White, Cynthia L. Sears, Eun J. Shin, Ali I. Amjad, Benny Weksler, Josephine L. Feliciano, Chen Hu, Vincent K. Lam, Valsamo Anagnostou. Circulating cell-free tumor DNA dynamics capture minimal residual disease with neoadjuvant immune checkpoint blockade plus chemoradiotherapy for patients with operable esophageal/gastroesophageal junction cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3374.

Introduction: Targeted next-generation sequencing (NGS) of cell-free DNA in plasma, referred to as liquid biopsy, has become a valuable diagnostic tool in clinical oncology. However, detection of variants related to clonal hematopoiesis (CH) is a major confounder that significantly impairs the clinical utility of liquid biopsies. Here we developed a machine-learning model to determine tumor versus CH origin of variants identified in plasma-only NGS. Methods: We assembled a training cohort of 352 variants identified by targeted deep plasma sequencing from 199 patients with stage I-IV breast, colorectal, esophageal, lung, and ovarian cancer, coupled with matched white blood cell (WBC) and tumor tissue NGS to allow determination of the reference origin for each plasma variant. We employed Extreme Gradient Boosting (XGBoost) to integrate fragment, variant, gene, and patient level features to predict tumor versus CH plasma variant origin, evaluating the performance of this approach within the training cohort using 10-fold cross-validation. We applied the fixed model to two independent validation cohorts: a small cell lung cancer (SCLC) cohort comprising of 74 variants from targeted plasma NGS from 26 patients and a multi-cancer cohort of 409 variants detected using the MSK-Impact panel from 74 patients with breast, colorectal, and prostate cancer. Results: Variant allele frequencies (VAF) did not differentiate tumor from CH variants, as the VAFs between tumor (median VAF 0.53%) and CH (median VAF 0.409%) variants in the training cohort were largely overlapping (area under the ROC curve-AUC 0.54, 95% confidence interval-CI 0.48-0.61). Similarly, individual fragmentomic features (mutant fragment length, cut points, and endpoint motifs) had limited ability to distinguish tumor from CH variants (AUC range 0.51-0.76). Using serial plasma samples, we identified stable statistical measures of differences in fragment feature distributions between mutant and wild type fragments; these were subsequently incorporated into an XGBoost machine-learning model along with variant, gene and patient features to predict tumor versus CH variant origin. Our model predicted variant origin with an AUC of 0.95 (95% CI 0.87-1) from 10-fold cross validation in the training cohort. The performance of the model was tested in independent SCLC and multi-cancer validation cohorts; the fixed model predicted plasma variant origin with an AUC of 0.87 (95% CI 0.73-1) and 0.89 (95% CI 0.86-0.92) respectively. Conclusion: We developed a machine-learning model that integrates patient, gene, variant and fragment features to predict tumor versus CH origin of plasma variants across solid tumors and NGS sequencing platforms. The ability to identify bona fide tumor variants in plasma-only sequencing fills a critical need in the clinical implementation of liquid biopsy-guided cancer therapy by reducing misinterpretation due to CH contamination. Citation Format: Jenna V. Canzoniero, Archana Balan, Jillian Phallen, Blair V. Landon, Lavanya Sivapalan, Benjamin Green, Zineb Belcaid, Susan C. Scott, Gavin Pereira, Vincent K. Lam, Ali H. Zaidi, Ronan J. Kelly, Christine L. Hann, Wade T. Iams, Christine M. Lovly, Patrick M. Forde, Gerrit A. Meijer, Geraldine R. Vink, Remond J. Fijneman, The MEDOCC Group, Victor E. Velculescu, Robert B. Scharpf, Valsamo Anagnostou. A machine learning approach to determine the cellular origin of variants in liquid biopsies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3366.

Background: Esophageal adenocarcinoma (EAC) is a deadly disease with limited treatment options. STING is a transmembrane protein that activates transcription of interferon genes, resulting in stimulation of APCs and enhanced CD8+ T-cell infiltration. The present study evaluates STING agonists, alone and in combination with radiation to determine durable anticancer activity in solid tumors. Materials and Methods: Esophagojejunostomy was performed on rats to induce reflux leading to the development of EAC. At 32 weeks post operatively, rats received intratumorally either 50 μg STING (ADU-S100) or placebo (PBS), +/– 16Gy radiation. Drug activity was evaluated by pre- and post- treatment MRI, histology, immunofluorescence and RT-PCR. Results: Mean MRI tumor volume decreased by 30.1% and 50.8% in ADU-S100 and ADU-S100 + radiation animals and increased by 76.7% and 152.4% in placebo and placebo + radiation animals, respectively (P < 0.0001). Downstream gene expression, pre- to on- and post- treatment, demonstrated significant upregulation of IFNβ, TNFα, IL-6, and CCL-2 in the treatment groups vs. placebo. On- or post- treatment, radiation alone, ADU-S100 alone, and ADU-S100 + radiation groups demonstrated enhanced PD-LI expression, induced by upregulation of CD8+ T-cells (p < 0.01). Conclusions: ADU-S100 +/– radiation exhibits potent antitumor activity and a promising immunomodulatory profile in a de novo EAC.

Aim: Study first-line (1L) treatment patterns and economic outcomes among patients with advanced metastatic gastric cancer (GC) and esophageal cancer (EC). Materials & methods: Newly diagnosed patients with systemic GC and EC treatments were identified between 1 January 2011 and 31 July 2017; costs were presented as per patient per month (PPPM) basis. Results: Study included 392 GC and 436 EC patients. Most frequently used 1L regimens were: 5-fluorouracil (5-FU) + oxaliplatin (22.5%) and epirubicin + cisplatin + 5-FU (ECF)/ECF modifications (21.9%) in patients with GC; and carboplatin + paclitaxel (29.6%) and 5-FU + oxaliplatin (11.5%) in EC patients. Mean all-cause costs were US$16,242 PPPM for GC, and $18,384 PPPM for EC during 1L treatment. Conclusion: GC and EC were resource intensive and costly. High costs and short treatment durations underscored a gap in care in 1L treatment.

INTRODUCTION: Dabrafenib plus trametinib was found to have robust antitumor activity in patients with BRAF V600E-mutant metastatic NSCLC (mNSCLC). We report updated survival analysis of a phase 2 study (NCT01336634) with a minimum of 5-year follow-up and updated genomic data.METHODS: Pretreated (cohort B) and treatment-naive (cohort C) patients with BRAF V600E-mutant mNSCLC received dabrafenib 150 mg twice daily and trametinib 2 mg once daily. The primary end point was investigator-assessed overall response rate per Response Evaluation Criteria in Solid Tumors version 1.1. Secondary end points were duration of response, progression-free survival, overall survival, and safety.RESULTS: At data cutoff, for cohorts B (57 patients) and C (36 patients), the median follow-up was 16.6 (range: 0.5-78.5) and 16.3 (range: 0.4-80) months, overall response rate (95% confidence interval [CI]) was 68.4% (54.8-80.1) and 63.9% (46.2-79.2), median progression-free survival (95% CI) was 10.2 (6.9-16.7) and 10.8 (7.0-14.5) months, and median overall survival (95% CI) was 18.2 (14.3-28.6) and 17.3 (12.3-40.2) months, respectively. The 4- and 5-year survival rates were 26% and 19% in pretreated patients and 34% and 22% in treatment-naive patients, respectively. A total of 17 patients (18%) were still alive. The most frequent adverse event was pyrexia (56%). Exploratory genomic analysis indicated that the presence of coexisting genomic alterations might influence clinical outcomes in these patients; however, these results require further investigation.CONCLUSIONS: Dabrafenib plus trametinib therapy was found to have substantial and durable clinical benefit, with a manageable safety profile, in patients with BRAF V600E-mutant mNSCLC, regardless of previous treatment.

Summary Background Margetuximab, a novel, investigational, Fc-engineered, anti-HER2 monoclonal antibody, is designed to more effectively potentiate innate immunity than trastuzumab. We aimed to evaluate the safety, tolerability, and antitumour activity of margetuximab plus pembrolizumab (an anti-PD-1 monoclonal antibody) in previously treated patients with HER2-positive gastro-oesophageal adenocarcinoma. Methods CP-MGAH22–05 was a single-arm, open-label, phase 1b–2 dose-escalation and cohort expansion study done at 11 academic centres in the USA and Canada and 15 centres in southeast Asia (Korea, Taiwan, and Singapore) that enrolled men and women aged 18 years or older with histologically proven, unresectable, locally advanced or metastatic, HER2-positive, PD-L1-unselected gastro-oesophageal adenocarcinoma, with an Eastern Cooperative Oncology Group performance status of 0 or 1, who had progressed after at least one previous line of therapy with trastuzumab plus chemotherapy in the locally advanced unresectable or metastatic setting. In the dose-escalation phase, nine patients were treated: three received margetuximab 10 mg/kg intravenously plus pembrolizumab 200 mg intravenously every 3 weeks and six received the recommended phase 2 dose of margetuximab 15 mg/kg plus pembrolizumab 200 mg intravenously every 3 weeks. An additional 86 patients were enrolled in the phase 2 cohort expansion and received the recommended phase 2 dose. The primary endpoints were safety and tolerability, assessed in the safety population (patients who received at least one dose of either margetuximab or pembrolizumab) and the objective response rate as assessed by the investigator according to both Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, in the response-evaluable population (patients with measurable disease at baseline and who received the recommended phase 2 dose of margetuximab and pembrolizumab). This trial is registered with ClinicalTrials.gov , NCT02689284 . Recruitment for the trial has completed and follow-up is ongoing. Findings Between Feb 11, 2016, and Oct 2, 2018, 95 patients were enrolled. Median follow-up was 19·9 months (IQR 10·7–23·1). The combination therapy showed acceptable safety and tolerability; there were no dose-limiting toxicities in the dose-escalation phase. The most common grade 3–4 treatment-related adverse events were anaemia (four [4%]) and infusion-related reactions (three [3%]). Serious treatment-related adverse events were reported in nine (9%) patients. No treatment-related deaths were reported. Objective responses were observed in 17 (18·48%; 95% CI 11·15–27·93) of 92 evaluable patients. Interpretation These findings serve as proof of concept of synergistic antitumour activity with the combination of an Fc-optimised anti-HER2 agent (margetuximab) along with anti-PD-1 checkpoint blockade (pembrolizumab). Funding MacroGenics.

Purpose: This randomized, multicenter, open-label, phase Ib/II study assessed durvalumab and tremelimumab in combination or as monotherapy for chemotherapy-refractory gastric cancer or gastroesophageal junction (GEJ) cancer. Patients and Methods: Second-line patients were randomized 2:2:1 to receive durvalumab plus tremelimumab (arm A), or durvalumab (arm B) or tremelimumab monotherapy (arm C), and third-line patients received durvalumab plus tremelimumab (arm D). A tumor-based IFNγ gene signature was prospectively evaluated as a potential predictive biomarker in second- and third-line patients receiving the combination (arm E). The coprimary endpoints were objective response rate and progression-free survival (PFS) rate at 6 months. Results: A total of 113 patients were treated: 6 in phase Ib and 107 (arm A, 27; arm B, 24; arm C, 12; arm D, 25; arm E, 19) in phase II. Overall response rates were 7.4%, 0%, 8.3%, 4.0%, and 15.8% in the five arms, respectively. PFS rates at 6 months were 6.1%, 0%, 20%, 15%, and 0%, and 12-month overall survival rates were 37.0%, 4.6%, 22.9%, 38.8%, and NA, respectively. Treatment-related grade 3/4 adverse events were reported in 17%, 4%, 42%, 16%, and 11% of patients, respectively. Conclusions: Response rates were low regardless of monotherapy or combination strategies. No new safety signals were identified. Including use of a tumor-based IFNγ signature and change in baseline and on-treatment circulating tumor DNA are clinically feasible and may be novel strategies to improve treatment response in this difficult-to-treat population.

Despite new therapeutic options, advanced gastric cancer remains associated with a poor prognosis compared with other cancers. Recent gains in the treatment of gastric cancer were accompanied by the identification of novel biomarkers associated with various cellular pathways and corresponding diagnostic technologies. It is expected that the standardization of clinical workflow and technological refinements in biomarker assessment will support greater personalization and further improve treatment outcomes. In this article, we review the current state of prognostic and predictive biomarkers in gastric cancer.

Background Although frequently used in the early pandemic, data on the effectiveness of COVID-19 convalescent plasma (CCP) remain mixed. We investigated the effectiveness and safety of CCP in hospitalized COVID-19 patients in real-world practices during the first two waves of the pandemic in a multi-hospital healthcare system in Texas. Methods and findings Among 11,322 hospitalized patients with confirmed COVID-19 infection from July 1, 2020 to April 15, 2021, we included patients who received CCP and matched them with those who did not receive CCP within ±2 days of the transfusion date across sites within strata of sex, age groups, days and use of dexamethasone from hospital admission to the match date, and oxygen requirements 4–12 hours prior to the match date. Cox proportional hazards model estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for effectiveness outcomes in a propensity score 1:1 matched cohort. Pre-defined safety outcomes were described. We included 1,245 patients each in the CCP treated and untreated groups. Oxygen support was required by 93% of patients at the baseline. The pre-defined primary effectiveness outcome of 28-day in-hospital all-cause mortality (HR = 0.85; 95%CI: 0.66,1.10) were similar between treatment groups. Sensitivity and stratified analyses found similar null results. CCP-treated patients were less likely to be discharged alive (HR = 0.82; 95%CI: 0.74, 0.91), and more likely to receive mechanical ventilation (HR = 1.48; 95%CI: 1.12, 1.96). Safety outcomes were rare and similar between treatment groups. Conclusion The findings in this large, matched cohort of patients hospitalized with COVID-19 and mostly requiring oxygen support at the time of treatment, do not support a clinical benefit in 28-day in-hospital all-cause mortality for CCP. Future studies should assess the potential benefits with specifically high-titer units in perhaps certain subgroups of patients (e.g. those with early disease or immunocompromised).

PURPOSE: With an increase in biomarker-directed therapies, tissue biopsy to identify targetable genomic and immunologic alterations has become the mainstay of managing patients with non–small-cell lung cancer (NSCLC); however, little is known about the associated economic impact and complication rate. This study assesses the frequency, complications, and costs of diagnostic and postprogression biopsy. METHODS: This retrospective, observational study was conducted using administrative claims data from more than 30 million commercially insured individuals in the United States (2006 to 2014). Data were analyzed for the overall population and by time of biopsy (diagnostic or postprogression biopsy). RESULTS: Of 20,013 eligible patients, 13,411 (67%) received a diagnostic biopsy, whereas only 2,056 (10%) received a postprogression biopsy (mean cost, $9,977 and $16,806, respectively). Complication rates were similar at diagnosis and after progression, on the day of biopsy (10% v 7%, respectively) and within 30 days (63% v 61%, respectively). Mean costs were higher among patients with a complication compared with those without a complication on the day of biopsy (diagnostic biopsy, $12,030 v $6,508, respectively; postprogression biopsy, $22,593 v $7,812, respectively), within 7 days of biopsy (diagnostic biopsy, $13,657 v $7,765, respectively; postprogression biopsy, $23,969 v $8,932, respectively), and within 30 days of biopsy (diagnostic biopsy, $24,968 v $15,988, respectively; postprogression biopsy, $30,293 v $12,494, respectively; P < .001 for all comparisons). CONCLUSION: From 2006 to 2014, postprogression biopsies were not common practice in NSCLC. Complication rates were similar at diagnosis and after progression, with mean costs higher among patients with a complication than those without a complication. With increasing demands for effective novel targeted therapies and safe testing methods, these data may be valuable in determining the budget impact and comparing complication rates with newer, less invasive molecular testing methods, including plasma circulating tumor DNA testing.

Objective The aim of the study was to investigate whether inhibition of Sonic Hedgehog (SHH) pathway would prevent progression of Barrett's Esophagus (BE) to esophageal adenocarcinoma. Background The hedgehog signaling pathway is a leading candidate as a molecular mediator of BE and esophageal adenocarcinoma (EAC). Repurposed use of existing off-patent, safe and tolerable drugs that can inhibit hedgehog, such as itraconazole, could prevent progression of BE to EAC. Methods The efficacy of itraconazole was investigated using a surgical rat reflux model of Barrett's Metaplasia (BM). Weekly intraperitoneal injections of saline (control group) or itraconazole (treatment group; 200 mg/kg) were started at 24 weeks postsurgery. Esophageal tissue was harvested at 40 weeks. The role of the Hh pathway was also evaluated clinically. Esophageal tissue was harvested after 40 weeks for pathological examination and evaluation of the SHH pathway by immunohistochemistry. Results BM was present in control animals 29 of 31 (93%) versus itraconazole 22 of 24 (91%). EAC was significantly lower in itraconazole 2 of 24 (8%) versus control 10 of 31 (32%), respectively (P = 0.033). Esophageal SHH levels were lower in itraconazole vs control (P = 0.12). In esophageal tissue from humans with recurrent or persistent dysplastic BE within 24 months of ablative treatment, strong SHH and Indian Hedgehog expression occurred in distal BE versus proximal squamous epithelium, odds ratio = 6.1 (95% confidence interval: 1.6, 23.4) and odds ratio = 6.4 (95% confidence interval: 1.2, 32.8), respectively. Conclusion Itraconazole significantly decreases EAC development and SHH expression in a preclinical animal model of BM. In humans, BE tissue expresses higher SHH, Indian Hedgehog, and bone morphogenic protein levels than normal squamous esophageal epithelium.

In patients with non–small-cell lung cancer treated with anti–PD-1/PD-L1 agents, no specific radiation parameter was significantly associated with immune-related (IR) pneumonitis. We identify on subset analysis of patients who developed IR pneumonitis and received chest radiation, patients were numerically more likely to have received chest radiation with curative intent than with palliative intent (89% vs. 11 that approached statistical significance. PURPOSE: To investigate the relationship between radiotherapy (RT), in particular chest RT, and development of immune-related (IR) pneumonitis in non–small-cell lung cancer (NSCLC) patients treated with anti–programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-LI). PATIENTS AND METHODS: Between June 2011 and July 2017, NSCLC patients treated with anti–PD-1/PD-L1 at a tertiary-care academic cancer center were identified. Patient, treatment, prior RT (intent, technique, timing, courses), and IR pneumonitis details were collected. Treating investigators diagnosed IR pneumonitis clinically. Diagnostic IR pneumonitis scans were overlaid with available chest RT plans to describe IR pneumonitis in relation to prior chest RT. We evaluated associations between patient, treatment, RT details, and development of IR pneumonitis by Fisher exact and Wilcoxon rank-sum tests. RESULTS: Of the 188 NSCLC patients we identified, median follow-up was 6.78 (range, 0.30–79.3) months and median age 66 (range, 39–91) years; 54% (n = 102) were male; and 42% (n = 79) had stage I-III NSCLC at initial diagnosis. Patients received anti–PD-1/PD-L1 monotherapy (n = 127, 68%) or PD-I/PD-LI -based combinations (n = 61, 32%). In the entire cohort, 70% (132/188) received any RT, 53% (100/188) chest RT, and 37% (70/188) curative-intent chest RT. Any grade IR pneumonitis occurred in 19% (36/188; 95% confidence interval, 13.8–25.6). Of those who developed IR pneumonitis and received chest RT (n = 19), patients were more likely to have received curative-intent versus palliative-intent chest RT (17/19, 89%, vs. 2/19, 11%; P = .051). Predominant IR pneumonitis appearances were ground-glass opacities outside high-dose chest RT regions. CONCLUSION: No RT parameter was significantly associated with IR pneumonitis. On subset analysis of patients who developed IR pneumonitis and who had received prior chest RT, IR pneumonitis was more common in patients who received curative-intent chest RT. Attention should be paid to NSCLC patients receiving curative-intent RT followed by anti –PD-I/PD-LI agents.

Treatment options and risk stratification for esophageal adenocarcinomas (EAC) currently rely on pathological criteria such as tumor staging. However, with advancement in immune modulated treatments, there is a need for accurate predictive biomarkers that will help identify high-risk patients and provide novel therapeutic targets. Hence, we analyzed as prognostic classifiers a host of histopathological parameters in conjunction with novel immune biomarkers. Specifically, gene expression levels for CXCL9, IDO1, LAG3, and TIM3 were established in treatment naive samples. Additionally, PD-L1 and CD8 positivity was determined by immunohistochemical staining. Based on our finding, a Cox model consisting of pathological complete response (CR), LAG3, and CXCL9 provided improved predictability for disease-free survival (DFS) compared to CR alone, and it demonstrated statistical significance for predictability of recurrence (p=0.0001). Likewise, for overall survival (OS), a Cox model constituted of TIM3, CR, and IDO1 performed better than CR alone, and it demonstrated statistical significance for predictability of survival (p = 0.0004). TIM3 was identified as the best predictor for OS (HR=4.43, p=0.0023). In conclusion, given the paucity of treatment options for EAC, evaluation of these biomarkers early in the disease course will lead to better risk stratification of patients and much needed alternatives for improved therapy.

Background ASP8273, a novel, small molecule, irreversible tyrosine kinase inhibitor (TKI) specifically inhibits the epidermal growth factor receptor (EGFR) in patients with activating mutations or EGFR T790M resistance mutations. The current study examines the efficacy, safety, and tolerability of ASP8273 versus erlotinib or gefitinib in patients with non-small-cell lung cancer (NSCLC) with activating EGFR mutations not previously treated with an EGFR inhibitor. Patients and methods This global, phase III, open-label, randomized study evaluated ASP8273 versus erlotinib/gefitinib in patients with locally advanced, metastatic, or unresectable stage IIIB/IV NSCLC with activating EGFR mutations. They were ineligible if they received prior chemotherapy for metastatic disease. The primary end point was progression-free survival (PFS), and secondary end points included overall survival, investigator-assessed PFS, best overall response rate (ORR), disease control rate, duration of response (DoR), and the safety/tolerability profile. Results Patients (n = 530) were randomized 1 : 1 to receive ASP8273 (n = 267) or erlotinib/gefitinib (n = 263). Patient demographics between both treatment groups were generally balanced. Median PFS was 9.3 months (95% CI 5.6–11.1 months) for patients receiving ASP8273 and 9.6 months (95% CI 8.8–NE) for the erlotinib/gefitinib group, with a hazard ratio of 1.611 (P = 0.992). The ORR in the ASP8273 group was 33% (95% CI 27.4–39.0) versus 47.9% (95% CI 41.7–54.1) in the erlotinib/gefitinib group. Median DoR was similar for both groups (9.2 months for ASP8273 versus 9.0 months for erlotinib/gefitinib). More grade ≥3 treatment-emergent adverse events (TEAEs) occurred in patients receiving ASP8273 than in those receiving erlotinib/gefitinib (54.7% versus 43.5%). An independent data monitoring committee carried out an interim safety analysis and recommended discontinuing the study due to toxicity and limited predicted efficacy of ASP8273 relative to erlotinib/gefitinib. Conclusions First-line ASP8273 did not show improved PFS or equivalent toxicities versus erlotinib/gefitinib. ClinicalTrial.gov number NCT02588261.

With increasing use of immune checkpoint inhibitors (ICIs) for advanced NSCLC, there is increasing recognition of immune-related adverse events associated with ICI use. We recently reported increased incidence of checkpoint inhibitor pneumonitis (CIP) in ICI-treated NSCLC patients. Since development of immune-related adverse events in other organ systems has been associated with either no change or even improvement in tumor response/cancer outcomes, we sought to better understand the impact of CIP development on overall survival in ICI-treated NSCLC patients. Using baseline and follow-up data collected on a cohort of 205 ICI-treated NSCLC patients, we used a multi-state modeling approach to understand the effect of developing CIP on the risk of death. We observed time-dependent changes in risk of developing and recovery from CIP, with an increased risk of both developing and recovering from CIP in the first year after initiating ICI. We found that developing CIP independently increased the risk of transitioning to death in both adjusted and unadjusted models. In the multivariate model, we found that the increase in mortality associated with CIP was only seen in patients with adenocarcinoma tumor histology. Collectively, these findings suggest that in NSCLC, development of CIP worsens survival in patients receiving immunotherapy.

Background: Preclinical and clinical data indicate that neoadjuvant chemoradiotherapy (CRT) may prime an anti-tumor immunological response in esophageal cancer driven by intratumoral CD8+ T cells and PD-L1 expression. LAG-3 is also highly expressed in esophagogastric cancers. The microbiome, a novel and potentially modifiable, biomarker of IO response, has not yet been examined in the neoadjuvant setting in esophageal cancer and is the goal of our study. Methods: Fecal samples were collected from patients with stage II/III esophageal or gastroesophageal junction carcinoma eligible for curative resection treated with the standard of care regimen of carboplatin paclitaxel (50mg/m2), radiation 50.4 Gy in 28 fractions and an Ivor-Lewis esophagectomy 6-10 weeks after last CRT and immunotherapy (IO) dose. Patients on arm A (n=11) received 2 cycles of induction with nivolumab plus 3 additional cycles on week 1, 3 and 5 of CRT. Patients on arm B (n=8) received nivolumab plus relatlimab on the same schedule (Clinical trial: NCT03044613). We examined longitudinal fecal samples from n=19 patients across both arms (n=90 samples) using 16S rRNA amplicon sequencing. Patients were classified based on pathological response: complete response (CR) and grades 1, 2, and 3 (G1, G2, G3) with increasing residual tumor visible in the resected specimen. Sequencing data was trimmed and filtered for contaminants, followed by high-resolution taxonomic assignment and normalization of reads across all samples. Analysis was performed using multiple metrics for alpha diversity and beta-diversity, with principal coordinates analysis/PERMANOVA, and pathway analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). Results: Patients with improved response in the neoadjuvant setting (CR/G1 vs G2/G3) grouped in distinct clusters using Bray-Curtis (p < 0.001). Patients with CR had higher alpha diversity, using both measures of richness and evenness, compared to patients with a G3 responses (p < 0.03). Specifically, family Bacteroidaceae and genus Bacteroides were enriched in patients with CR vs G3 (p < 0.02). At the species level, B. finegoldii, B. ovatus, and B. uniformis were enriched in patients with CR vs G3 (p < 0.02). In contrast, genus Klebsiella and Clostridium termitidis were enriched in patients with a poor response, G3 (p Conclusions: Patients with operable esophageal cancer and improved responses to combined CRT and IO had distinct microbiome profiles enriched in multiple Bacteroides species. Further analyses and validation efforts are underway to confirm metabolomic pathways. Citation Format: Fyza Y. Shaikh, James R. White, Ronan J. Kelly, Ali H. Zaidi, Jenna V. Canzoniero, Josephine L. Feliciano, Russell K. Hales, K Ranh Voong, Richard J. Battafarano, Blair A. Jobe, Stephen C. Yang, Stephen Broderick, Jinny Ha, Kellie N. Smith, Elizabeth Thompson, Eun J. Shin, Ali I. Amjad, Patrizia Guerrieri, Benny Weksler, Chen Hu, Valsamo Anagnostou, Vincent K. Lam, Cynthia L. Sears. Patients with operable esophageal cancer and improved responses to combined chemoradiotherapy and immunotherapy display distinct microbiome profiles enriched in multiple Bacteroides species [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1973.

The aim of this study was to assess the impact of chemoradiation on the immune microenvironment to influence and optimally design future neoadjuvant clinical trials.Programmed death (PD)-1 inhibitors in metastatic gastroesophageal cancer have demonstrated response rates of approximately 25% in programmed death ligand-1 (PD-L1+) tumors. Unfortunately, the majority of patients do not respond. Therefore, a rationale strategy of combining immunotherapeutic agents with chemoradiation in earlier stage esophageal cancer may prevent metastatic disease in patients.To determine the effects of chemoradiation on resected esophageal adenocarcinomas, we examined the immune microenvironment pre- and post-chemoradiation using immunohistochemistry, quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), and functional analysis of tumor-infiltrating lymphocytes. Additionally, to assess the duration and dependency of radiation-induced PD-L1 upregulation, a surgical rat reflux model of esophageal adenocarcinoma is used. First, tumor-bearing animals were dosed with single-fraction 13Gy or 16Gy radiation to determine safety, dose correlation, and PD-L1 upregulation using qRT-PCR post-radiation. Next, longitudinal PD-L1 expression levels within individual animals were determined using serial endoscopic biopsies at baseline, 1, 5, and 9 weeks post 16Gy radiation.The majority of cancers displayed enhanced interferon γ and activated CD8+ T lymphocytes at the tumor stroma interface. These tumors also demonstrated enhanced upregulation of PD-L1 and multiple other immune checkpoints including TIM3, GITR, IDO1, LAG3, OX40, and KIR. The animal model results indicated PD-L1 upregulation is dose-dependent and transiently elevated post radiation exposure.Collectively, these findings provide insights into the evolving immune landscape after chemoradiation and have significant implications for neoadjuvant trial designs that will combine radiotherapy with immune checkpoint inhibitors.

Approximately 9 months of the severe acute respiratory syndrome coronavius-2 (SARS-CoV-2 [COVID-19]) spreading across the globe has led to widespread COVID-19 acute hospitalizations and death. The rapidity and highly communicable nature of the SARS-CoV-2 outbreak has hampered the design and execution of definitive randomized, controlled trials of therapy outside of the clinic or hospital. In the absence of clinical trial results, physicians must use what has been learned about the pathophysiology of SARS-CoV-2 infection in determining early outpatient treatment of the illness with the aim of preventing hospitalization or death. This article outlines key pathophysiological principles that relate to the patient with early infection treated at home. Therapeutic approaches based on these principles include 1) reduction of reinoculation, 2) combination antiviral therapy, 3) immunomodulation, 4) antiplatelet/antithrombotic therapy, and 5) administration of oxygen, monitoring, and telemedicine. Future randomized trials testing the principles and agents discussed will undoubtedly refine and clarify their individual roles; however, we emphasize the immediate need for management guidance in the setting of widespread hospital resource consumption, morbidity, and mortality.

BACKGROUND: KRAS mutations are identified in approximately 25% of non-small cell lung cancer (NSCLC) cases and are associated with resistance to currently available targeted therapies. The MET oncogene may be implicated in malignant progression of KRAS-mutant tumors. In a pre-specified subset analysis of KRAS mutant cancers in an earlier phase 2 study of erlotinib plus the oral MET inhibitor tivantinib, combination therapy was associated with substantial clinical benefit compared to erlotinib alone (progression-free survival [PFS] HR 0.18; P

Background In the absence of a targeted oncogenic driver mutation or high programmed death-ligand 1 expression, systemic therapy with platinum-based doublet chemotherapy with or without bevacizumab has been the standard treatment in advanced or metastatic non-small cell lung cancer (NSCLC). Metformin has been shown to have antitumor effects via a variety of insulin-dependent and insulin-independent mechanisms and to be potentially synergistic with chemotherapy. Materials and Methods This open-label single-center phase II study (NCT01578551) enrolled patients with chemotherapy-naïve advanced or metastatic nonsquamous NSCLC and randomized them (3:1) to receive carboplatin, paclitaxel, and bevacizumab with (Arm A) or without (Arm B) concurrent metformin for four to six cycles followed by maintenance therapy with bevacizumab ± metformin continued until disease progression, intolerable toxicity, or study withdrawal. The primary outcome was 1-year progression free survival (PFS). Secondary outcomes included overall survival, response to therapy, and toxicity. Results A total of 25 patients were enrolled from August 2012 to April 2015, of whom 24 received at least one cycle of therapy administration. The study was stopped early due to slow accrual and changes in standard first-line therapy of advanced NSCLC. The 1-year PFS on Arm A (n = 18) was 47% (95% confidence interval [CI]: 25%–88%), which exceeded the historical control 1-year PFS of 15%. Median overall survival of patients treated on Arm A was 15.9 months (95% CI: 8.4–not available [NA]) and 13.9 months (95% CI: 12.7–NA) on Arm B. There were no significant differences in toxicity between the study arms. Conclusion To the authors' knowledge, this is the first study to show a significant benefit in PFS with the use of metformin in this patient population and is a signal of efficacy for metformin in advanced NSCLC. Implications for Practice The anticancer effects of metformin continue to be elucidated. To the authors' knowledge, this is the first trial in nondiabetic advanced non-small cell lung cancer patients to show a significant change in outcome with the addition of metformin to standard first-line chemotherapy. Well tolerated and widely available, metformin is a drug that should be considered for further study in the lung cancer treatment landscape.

PURPOSE/OBJECTIVE(S) Esophageal adenocarcinoma is the sixth leading cause of cancer-related deaths in the United States. For locally advanced patients, neoadjuvant chemoradiotherapy followed by surgery is the standard of care. Risk stratification relies heavily on clinicopathologic features, particularly pathologic response, which is inadequate. This highlights the need for the development of biomarkers that can help improve outcomes. Herein, we have developed 2 distinct biomarker signatures to either predict response to neoadjuvant therapy or stratify patients into risk categories for survival. MATERIALS/METHODS We assembled a cohort of 34 patients with locally advanced esophageal adenocarcinoma, with the majority (21) receiving concurrent chemoradiotherapy with carboplatin/paclitaxel. A capture based targeted sequencing was performed in paired biopsy specimens obtained at baseline, 3- and 6-weeks post-treatment. Differentially mutated gene analysis between responders and non-responders of treatment was performed to determine predictors of response. A univariate Cox proportional hazard regression was used to examine associations between gene mutation status and overall survival. A risk score was then calculated for each patient using a linear combination of univariate coefficient and mutation status of gene. RESULTS 15 patients (71%) receiving the CROSS regimen were classified as responders. Among responders to chemotherapy, the most frequently mutated genes were MKI67, SYNE1, PCLO, MSH3, RECQL4, NOTCH2, ILR7, CIITA, LRRK2 and EML4. Tumor mutation count was significantly reduced for these genes in post-treatment samples (P = 5.89E-03). We have identified a 3 gene signature based on mutations in EPHA5, BCL6, and ERBB2 that robustly predicts response to carboplatin/paclitaxel based neoadjuvant therapy. For this model, sensitivity is 84.6% and specificity is 100%. In the overall cohort, a 9 gene signature using APC, MAP3K6, ETS1, CSF3R, PDGFRB, GATA2, ARID1A, and FGF6, was also created that significantly stratifies patients into risk categories, prognosticating for improved relapse-free (P = 0.005) and overall survival (P = 3.325E-06). Sensitivity for this model is 73.33% and specificity is 94.74%. CONCLUSION We have identified a 3-gene signature (EPHA5, BCL6 and ERBB2) that is predictive of response to neoadjuvant therapy and a separate 9 gene classifier which prognosticates for survival outcomes. These provide significant potential for personalized management of locally advanced esophageal cancer.

Purpose: Acquired EGFR T790M mutations are the most frequently identified resistance mechanism to EGFR tyrosine kinase inhibitors (TKI) in patients with EGFR-mutant lung cancers. ASP8273 is a third-generation EGFR TKI with antitumor activity in preclinical models of EGFR-mutant lung cancer that targets mutant EGFR, including EGFR T790M. Experimental Design: In this multicohort, phase I study (NCT02113813), escalating doses of ASP8273 (25–500 mg) were administered once daily to non–small cell lung cancer (NSCLC) patients with disease progression after prior treatment with an EGFR TKI. EGFR T790M was required for all cohorts, except the dose escalation cohort. Primary endpoints were safety/tolerability; secondary endpoints were determination of the RP2D, pharmacokinetic profile, and preliminary antitumor activity of ASP8273. Evaluation of the use of EGFR mutations in circulating free DNA (cfDNA) as a biomarker of ASP8273 treatment effects was an exploratory endpoint. Results: A total of 110 patients were treated with ASP8273 across dose escalation (n = 36), response–expansion (n = 36), RP2D (300 mg; n = 19) and food–effect (n = 19) cohorts. The most common treatment-emergent adverse events included diarrhea, nausea, fatigue, constipation, vomiting, and hyponatremia. Across all doses, in patients with EGFR T790M, the response rate was 30.7% (n = 27/88; 95% CI, 19.5%–44.5%), and median progression-free survival was 6.8 months (95% CI, 5.5–10.1 months). EGFR mutations in cfDNA, both the activating mutation and EGFR T790M, became undetectable in most patients in the setting of clinical response and reemerged upon disease progression. Conclusions: ASP8273 was well tolerated and promoted antitumor activity in patients with EGFR-mutant lung cancer with disease progression on prior EGFR TKI therapy. Clin Cancer Res; 23(24); 7467–73. ©2017 AACR.

Esophageal adenocarcinoma (EAC) is a deadly disease with limited therapeutic options. In the present study, we determined the preclinical efficacy of CDK4/6 inhibitor abemaciclib for treatment of EAC. In vitro, apoptosis, proliferation, and pathway regulation were evaluated in OE19, OE33, and FLO1 EAC cell lines. In vivo, esophagojejunostomy was performed on rats to induce EAC. At 36 weeks post-surgery, MRI and endoscopic biopsy established baseline tumor volume and molecular correlates, respectively. Next, the study animals were randomized to 26mg/kg intraperitoneal abemaciclib treatment or vehicle control for 28 days. Pre and post treatment MRIs, histopathology, and qRT-PCR were utilized to determine response. Our results demonstrated treatment with abemaciclib lead to increased apoptosis, and decreased proliferation in OE19 (p=0.185), OE33 (p=0.048), and FLO1 (p=0.043) with anticipated downstream molecular inhibition. In vivo, 78.9% of treatment animals demonstrated >20% tumor volume decrease (placebo 0%). Mean tumor volume changed in the treatment arm by -65.5% (placebo +133.5%) (p

We examined the utility of serial liquid biopsies to monitor clonal dynamics and predict pathologic response in patients with esophageal/gastroesophageal junction (E/GEJ) cancer undergoing treatment with neoadjuvant immunotherapy and concurrent chemoradiation (CA209-906; NCT03044613). Methods: Using Targeted Error Correction sequencing (TEC-Seq), we performed high-depth next generation sequencing on 79 serial plasma samples from 16 patients with operable stage II/III E/GEJ cancer undergoing treatment with neoadjuvant nivolumab, followed by nivolumab plus chemo-radiation and surgery as part of the CA209-906 trial. Liquid biopsies were evaluated pre-treatment, after each of two cycles of neoadjuvant nivolumab, and after concurrent nivolumab and chemoradiation immediately prior to surgery, for an average of 4 time points per patient. Deep sequencing of matched leukocyte DNA and whole exome sequencing (WES) of pre-treatment tumors was performed. The origin of plasma variants was determined by comparison to tumor WES (tumor-derived) and leukocyte TEC-Seq (clonal hematopoiesis (CH)-derived or germline) and their clonal dynamics over time were evaluated. Resected tumors were reviewed by central pathology and percent residual tumor was estimated. Patients were followed for an average of 2 years post-surgery. Results: Eight of 16 patients had detectable circulating tumor-derived DNA (ctDNA) at any time point. Additionally, 13 CH-derived mutations were detected in plasma of 8 patients. The number of CH-derived mutations was correlated with increasing patient age. Identification and removal of CH-derived mutations via comparison to matched leukocyte sequencing allowed for accurate assessment of kinetics of bona fide tumor-derived mutations in plasma. Tumor mutation burden as determined by tumor WES was not associated with pathological response (mean baseline mutations per exome 90 vs 81 for patients with residual disease >20% and 20% (50% vs 23% with or without detectable ctDNA respectively). ctDNA clearance, defined as detectable ctDNA at one or more earlier time points that subsequently becomes undetectable before surgery, occurred in 5 patients and was associated with improved pathologic response (80% of patients with ctDNA clearance had residual tumor Conclusion: Comprehensive analyses of ctDNA from E/GEJ patients undergoing neoadjuvant immunotherapy with concurrent chemoradiation revealed ctDNA dynamics that were associated with pathologic response and disease recurrence. These approaches may be used to identify patients at high risk for disease progression. Citation Format: Jenna VanLiere Canzoniero, Vincent Lam, Zineb Belcaid, Mara Lanis, Lamia Rhymee, Blair Landon, Archana Balan, Kristen Marrone, Patrick Forde, Benjamin Levy, David Ettinger, Heather Schneider, Hanika Rodavia, Richard Battafarano, Stephen Yang, Stephen Broderick, Jinny Ha, Blair Jobe, Ali Zaidi, Elizabeth Thompson, Julie Brahmer, Victor Velculescu, Ronan Kelly, Josephine Feliciano, Valsamo Anagnostou. Liquid biopsy approaches for determining pathologic response to neoadjuvant immunotherapy in esophageal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 538.

4003 Background: In CheckMate 577 (NCT02743494), NIVO demonstrated a significant and clinically meaningful improvement in disease-free survival (DFS; primary endpoint) vs placebo (PBO) and was well tolerated in patients (pts) with resected (R0) stage II/III EC/GEJC who received neoadjuvant CRT and had residual pathologic disease. Median DFS doubled with NIVO vs PBO (22.4 vs 11.0 months; HR 0.69; 96.4% CI 0.56–0.86; P = 0.0003). Serious treatment-related adverse events (TRAEs) and TRAEs leading to discontinuation were reported for < 10% of pts with NIVO and 3% with PBO. Methods: Pts were randomized 2:1 to NIVO 240 mg or PBO Q2W for 16 weeks, followed by NIVO 480 mg or PBO Q4W. Here, we present additional efficacy, safety, and quality-of-life (QoL) data from CheckMate 577. Results: 794 pts were randomized (NIVO, 532; PBO, 262). Distant recurrence was reported for 29% vs 39% and locoregional recurrence for 12% vs 17% of pts in the NIVO vs PBO groups, respectively. Median distant metastasis-free survival was 28.3 vs 17.6 months with NIVO vs PBO (HR 0.74; 95% CI 0.60–0.92). Median progression-free survival 2 (PFS2; time from randomization to progression after subsequent systemic therapy, initiation of second subsequent systemic therapy, or death, whichever is earlier) was not reached with NIVO vs 32.1 months with PBO (HR 0.77; 95% CI 0.60–0.99). TRAEs with potential immunologic etiology (select TRAEs; sTRAEs) reported for NIVO are presented in the table. Results for the FACT-ECS and FACT-G7 showed similar trends for QoL improvement from baseline for NIVO and PBO during treatment and maintained benefit post-treatment. Conclusions: Adjuvant NIVO demonstrated clinically meaningful efficacy, an acceptable safety profile, and maintained QoL, providing further support for its use as a new standard of care for pts with resected EC/GEJC who received neoadjuvant CRT with residual pathologic disease. Clinical trial information: NCT02743494. [Table: see text]

4042 Background: Improving immunotherapy efficacy remains an unmet need in esophagogastric cancer and a deeper understanding of tumor and immune system dynamics during therapy may tailor immuno-oncology approaches. Methods: We performed whole exome sequencing (WES) and bulk RNA sequencing (RNAseq) of 70 serial tumor samples from 23 patients with stage II/III esophageal/gastroesophageal junction (E/GEJ) cancer treated on a phase 1B clinical trial with neoadjuvant nivolumab with or without relatlimab (anti-LAG-3) and chemoradiation followed by surgery (NCT03044613; CA209-906). Pathologic response was measured by tumor regression at the time of resection. Median follow up was 23 months post-surgery. Serial tumor samples were collected prior to therapy, after 2 cycles of induction immune checkpoint blockade (ICB), and at the time of resection. Twenty-two baseline tumor/normal DNA pairs were analyzed by WES and 48 serial tumor samples were analyzed by RNAseq. WES data was analyzed to identify somatic mutations, generate tumor mutation burden (TMB) estimates and assess the fraction of expressed mutations in conjunction with RNAseq data. Immune cell subset composition was determined by RNAseq data deconvolution by CIBERSORT and gene set enrichment analyses were performed utilizing GSEA. B-cell density was inferred by immunoglobulin rearrangements detected by RNAseq. Results: Gene set enrichment expression analyses revealed an upregulation of effector pro-inflammatory cytokines after induction ICB. Interferon-gamma, interferon-alpha and TNF-alpha related genes were significantly upregulated after induction ICB compared to baseline (p < 0.0001). In contrast, significant downregulation of E2F targets (p = 0.002), G2M checkpoint genes (p = 0.005) and DNA damage repair genes (p = 0.004) was observed post ICB; enrichment analyses were independent of response to therapy and treatment arm. While TMB was not predictive of pathologic response (p = 0.22), patients with tumors harboring a higher number of expressed mutations were more likely to achieve a pathologic complete response (pCR; p = 0.026). RNAseq deconvolution analyses revealed a higher B-cell density post ICB induction in tumors with pCR (p = 0.018). Furthermore, an increased baseline content of intra-tumoral activated M1 macrophages differentiated tumors from patients achieving a pCR (p = 0.0034), which was further exemplified post induction ICB. Conclusions: Neoadjuvant immunotherapy induces an inflammatory immune response in the tumor microenvironment that is linked with tumor elimination and pathologic response. Our findings highlight the importance of nuanced multi-omics analyses to understand the wiring of response to immunotherapy and guide therapy for E/GEJ cancer.

Aim To efficiently replicate the biology and pathogenesis of human esophageal adenocarcinoma (EAC) using the modified Levrat model of end-to-side esophagojejunostomy. Methods End-to-side esophagojejunostomy was performed on rats to induce gastroduodenoesophageal reflux to develop EAC. Animals were randomly selected and serially euthanized at 10 (n = 6), 17 (n = 8), 24 (n = 9), 31 (n = 6), 38 (n = 6), and 40 (n = 6) wk postoperatively. The esophagi were harvested for downstream histopathology and gene expression. Histological evaluation was completed to determine respective rates of carcinogenic development. Quantitative reverse transcription-polymerase chain reaction was performed to determine gene expression levels of MUC2, CK19, and CK20, and results were compared to determine significant differences throughout disease progression stages. Results The overall study mortality was 15%. Causes of mortality included anastomotic leak, gastrointestinal hemorrhage, stomach ulcer perforation, respiratory infection secondary to aspiration, and obstruction due to tumor or late anastomotic stricture. 10 wk following surgery, 100% of animals presented with esophagitis. Barrett's esophagus (BE) was first observed at 10 wk, and was present in 100% of animals by 17 wk. Dysplasia was confirmed in 87.5% of animals at 17 wk, and increased to 100% by 31 wk. EAC was first observed in 44.4% of animals at 24 wk and increased to 100% by 40 wk. In addition, two animals at 38-40 wk post-surgery had confirmed macro-metastases in the lung/liver and small intestine, respectively. MUC2 gene expression was progressively down-regulated from BE to dysplasia to EAC. Both CK19 and CK20 gene expression significantly increased in a stepwise manner from esophagitis to EAC. Conclusion Esophagojejunostomy was successfully replicated in rats with low mortality and a high tumor burden, which may facilitate broader adoption to study EAC development, progression, and therapeutics.